Publications by authors named "Amidou Samie"

67 Publications

Synthesis, Characterization and In Vitro Antibacterial Evaluation of Conjugated Silver Nanoparticles.

Nanomaterials (Basel) 2021 Jun 15;11(6). Epub 2021 Jun 15.

School of Mathematics and Natural Science, Microbiology Department, University of Venda, Private Bag x5050, Thohoyandou 0950, South Africa.

In the present study, silver nanoparticles (AgNPs) were synthesized using both the chemical and biological methods and conjugated with extracts. These were then characterized and evaluated for antimicrobial activities against multi-drug resistant pathogens, such as methicillin-resistant (MRSA), and . Nanoparticles were analyzed with UV-visible spectrophotometer, transmission electron microscopy (TEM), and energy dispersive X-ray analysis (EDX). Silver nanoparticles, extracts, and the conjugates were also analyzed with Fourier transform infrared spectroscopy (FTIR). As a result, quasi-sphere-shaped AgNPs with sizes ranging from 5 to 33 nm and spherically shaped AgNPs with sizes ranging from 3 to 25 nm were formed from chemical and biological synthesis, respectively. A well diffusion assay showed that the activity of silver nanoparticles was most improved with acetone extract against all tested bacteria with diameters in the range of 19-24 mm. The lowest MIC value of 0.0063 mg/mL against MRSA was observed when biologically synthesized AgNPs were conjugated with acetone and water extracts. Chemically synthesized silver nanoparticles showed the lowest MIC value of 0.0063 mg/mL against when conjugated with acetone and methanol extracts. This study indicates that silver nanoparticles conjugated with tubers extracts exhibit strong antibacterial activities against multi-drug resistant bacterial pathogens. Therefore, biosynthesized conjugates could be utilized as antimicrobial agents for effective disease management due to the synergistic antibacterial activity that was observed.
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http://dx.doi.org/10.3390/nano11061568DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8232158PMC
June 2021

Molecular epidemiology of Microsporidia among HIV-positive and HIV-negative patients in the Limpopo province, South Africa.

J Infect Dev Ctries 2021 May 31;15(5):710-718. Epub 2021 May 31.

Department of Medical Laboratory Sciences, College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates.

Introduction: Human microsporidiosis represents an important and rapidly emerging opportunistic disease. The present study investigated the prevalence of microsporidia among HIV positive and HIV negative patients with or without diarrhoea in Vhembe and Mopani Districts in the Limpopo Province.

Methodology: A total of 170 stool samples were collected from these patients and microsporidia species was detected using a Real-Time PCR targeting a conserved region of the small ribosomal subunit rRNA (SSU-rRNA) gene of Enterocytozoon bieneusi, Encephalitozoon intestinalis, Encephalitozoon hellem, and Encephalitozoon cuniculi.

Results: Fifty six (32.9%) were positive for microsporidia. The prevalence was higher in HIV negative patients (36.6%) while 24.1% of patients who were HIV positive had microsporidia. Microsporidia was more common among patients aged between 1 and 10 years (52.6%). However among the HIV positive patients, microsporidia prevalence was higher among those that were not taking antiretrovirals (ARVs) compared to those who were on ARVs, (36.6%) and (24.1%), respectively. Microsporidia was also noted to be significantly associated with diarrheal and stomach pains; p = 0.02 and p = 0.048, respectively. Furthermore, microsporidia infections was more prevalent among patients who had animals at home (p = 0.037).

Conclusions: Study has shown a high prevalence of microsporidia among patients attending primary health centers in the Mopani District for the first time. Prevalence of microsporidia was higher among HIV negative and HIV positive patients who were not on ARV treatment. Keeping animals in the household appeared to be a risk of getting infected with microsporidia. Further studies are needed to determine the genetic characteristics of these organisms in the study population.
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http://dx.doi.org/10.3855/jidc.12988DOI Listing
May 2021

Enhanced passive surveillance dengue infection among febrile children: Prevalence, co-infections and associated factors in Cameroon.

PLoS Negl Trop Dis 2021 04 16;15(4):e0009316. Epub 2021 Apr 16.

"Chantal Biya" International Reference Centre for Research on HIV and AIDS Prevention and Management (CIRCB), Yaoundé, Cameroon.

Dengue virus (DENV) causes a spectrum of diseases ranging from asymptomatic, mild febrile to a life-threatening illness: dengue hemorrhagic fever. The main clinical symptom of dengue is fever, similar to that of malaria. The prevalence of dengue virus infection, alone or in association with other endemic infectious diseases in children in Cameroon is unknown. The aim of this study was to determine the prevalence of dengue, malaria and HIV in children presenting with fever and associated risk factors. Dengue overall prevalence was 20.2%, Malaria cases were 52.7% and HIV cases represented 12.6%. The prevalence of dengue-HIV co-infection was 6.0% and that of Malaria-dengue co-infection was 19.5%. Triple infection prevalence was 4.3%. Dengue virus infection is present in children and HIV-Dengue or Dengue- Malaria co-infections are common. Dengue peak prevalence was between August and October. Sex and age were not associated with dengue and dengue co-infections. However, malaria as well as HIV were significantly associated with dengue (P = 0.001 and 0.028 respectively). The diagnosis of dengue and Malaria should be carried out routinely for better management of fever.
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http://dx.doi.org/10.1371/journal.pntd.0009316DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8051767PMC
April 2021

Seasonality of drinking water sources and the impact of drinking water source on enteric infections among children in Limpopo, South Africa.

Int J Hyg Environ Health 2021 Jan 23;231:113640. Epub 2020 Oct 23.

Department of Public Health Sciences, University of Virginia, Charlottesville, VA, 22908, USA; Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, 22908, USA. Electronic address:

Enteric infections and water-related illnesses are more frequent during times of relative water abundance, especially in regions that experience bimodal rainfall patterns. However, it is unclear how seasonal changes in water availability and drinking water source types affect enteric infections in young children. This study investigated seasonal shifts in primary drinking water source type and the effect of water source type on enteric pathogen prevalence in stool samples from 404 children below age 5 in rural communities in Limpopo Province, South Africa. From wet to dry season, 4.6% (n = 16) of households switched from a source with a higher risk of contamination to a source with lower risk, with the majority switching to municipal water during the dry season. In contrast, 2.6% (n = 9) of households switched from a source with a lower risk of contamination to a source with higher risk. 74.5% (n = 301) of the total households experienced interruptions in their water supply, regardless of source type. There were no significant differences in enteric pathogen prevalence between drinking water sources. Intermittent municipal water distribution and household water use and storage practices may have a larger impact on enteric infections than water source type. The limited differences in enteric pathogen prevalence in children by water source could also be due to other exposure pathways in addition to drinking water, for example through direct contact and food-borne transmission.
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http://dx.doi.org/10.1016/j.ijheh.2020.113640DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7736504PMC
January 2021

Duration of Postdiarrheal Enteric Pathogen Carriage in Young Children in Low-resource Settings.

Clin Infect Dis 2021 06;72(11):e806-e814

Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, USA.

Background: Prolonged enteropathogen shedding after diarrhea complicates the identification of etiology in subsequent episodes and is an important driver of pathogen transmission. A standardized approach has not been applied to estimate the duration of shedding for a wide range of pathogens.

Methods: We used a multisite birth cohort of children 0-24 months of age from whom diarrheal and monthly nondiarrheal stools were previously tested by quantitative polymerase chain reaction for 29 enteropathogens. We modeled the probability of detection of the etiologic pathogen before and after diarrhea using a log-normal accelerated failure time survival model and estimated the median duration of pathogen carriage as well as differences in subclinical pathogen carriage 60 days after diarrhea onset in comparison to a prediarrhea baseline.

Results: We analyzed 3247 etiologic episodes of diarrhea for the 9 pathogens with the highest attributable burdens of diarrhea. The median duration of postdiarrheal carriage varied widely by pathogen, from about 1 week for rotavirus (median, 8.1 days [95% confidence interval {CI}, 6.2-9.6]) to >1 month for Cryptosporidium (39.5 days [95% CI, 30.6-49.0]). The largest increases in subclinical pathogen carriage before and after diarrhea were seen for Cryptosporidium (prevalence difference between 30 days prior and 60 days after diarrhea onset, 0.30 [95% CI, .23-.39]) and Shigella (prevalence difference, 0.21 [95% CI, .16-.27]).

Conclusions: Postdiarrheal shedding was widely variable between pathogens, with strikingly prolonged shedding seen for Cryptosporidium and Shigella. Targeted antimicrobial therapy and vaccination for these pathogens may have a relatively large impact on transmission.
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http://dx.doi.org/10.1093/cid/ciaa1528DOI Listing
June 2021

Impact of Low-Cost Point-of-Use Water Treatment Technologies on Enteric Infections and Growth among Children in Limpopo, South Africa.

Am J Trop Med Hyg 2020 10;103(4):1405-1415

Department of Public Health Sciences, University of Virginia, Charlottesville, Virginia.

Enteric infections early in life have been associated with poor linear growth among children in low-resource settings. Point-of-use water treatment technologies provide effective and low-cost solutions to reduce exposure to enteropathogens from drinking water, but it is unknown whether the use of these technologies translates to improvements in child growth. We conducted a community-based randomized controlled trial of two water treatment technologies to estimate their effects on child growth in Limpopo, South Africa. We randomized 404 households with a child younger than 3 years to receive a silver-impregnated ceramic water filter, a silver-impregnated ceramic tablet, a safe-storage water container alone, or no intervention, and these households were followed up quarterly for 2 years. We estimated the effects of the interventions on linear and ponderal growth, enteric infections assessed by quantitative molecular diagnostics, and diarrhea prevalence. The silver-impregnated ceramic water filters and tablets consistently achieved approximately 1.2 and 3 log reductions, respectively, in total coliform bacteria in drinking water samples. However, the filters and tablets were not associated with differences in height (height-for-age -score differences compared with no intervention: 0.06, 95% CI: -0.29, 0.40, and 0.00, 95% CI: -0.35, 0.35, respectively). There were also no effects of the interventions on weight, diarrhea prevalence, or enteric infections. Despite their effectiveness in treating drinking water, the use of the silver-impregnated ceramic water filters and tablets did not reduce enteric infections or improve child growth. More transformative water, sanitation, and hygiene interventions that better prevent enteric infections are likely needed to improve long-term child growth outcomes.
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http://dx.doi.org/10.4269/ajtmh.20-0228DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7543807PMC
October 2020

Epidemiology of Shigella infections and diarrhea in the first two years of life using culture-independent diagnostics in 8 low-resource settings.

PLoS Negl Trop Dis 2020 08 17;14(8):e0008536. Epub 2020 Aug 17.

Department of Pediatrics and Child Health and Biological & Biomedical Sciences, Aga Khan University, Karachi, Pakistan.

Culture-independent diagnostics have revealed a larger burden of Shigella among children in low-resource settings than previously recognized. We further characterized the epidemiology of Shigella in the first two years of life in a multisite birth cohort. We tested 41,405 diarrheal and monthly non-diarrheal stools from 1,715 children for Shigella by quantitative PCR. To assess risk factors, clinical factors related to age and culture positivity, and associations with inflammatory biomarkers, we used log-binomial regression with generalized estimating equations. The prevalence of Shigella varied from 4.9%-17.8% in non-diarrheal stools across sites, and the incidence of Shigella-attributable diarrhea was 31.8 cases (95% CI: 29.6, 34.2) per 100 child-years. The sensitivity of culture compared to qPCR was 6.6% and increased to 27.8% in Shigella-attributable dysentery. Shigella diarrhea episodes were more likely to be severe and less likely to be culture positive in younger children. Older age (RR: 1.75, 95% CI: 1.70, 1.81 per 6-month increase in age), unimproved sanitation (RR: 1.15, 95% CI: 1.03, 1.29), low maternal education (<10 years, RR: 1.14, 95% CI: 1.03, 1.26), initiating complementary foods before 3 months (RR: 1.10, 95% CI: 1.01, 1.20), and malnutrition (RR: 0.91, 95% CI: 0.88, 0.95 per unit increase in weight-for-age z-score) were risk factors for Shigella. There was a linear dose-response between Shigella quantity and myeloperoxidase concentrations. The burden of Shigella varied widely across sites, but uniformly increased through the second year of life and was associated with intestinal inflammation. Culture missed most clinically relevant cases of severe diarrhea and dysentery.
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http://dx.doi.org/10.1371/journal.pntd.0008536DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7451981PMC
August 2020

Functionalization and antimicrobial evaluation of ampicillin, penicillin and vancomycin with Pyrenacantha grandiflora Baill and silver nanoparticles.

Sci Rep 2020 07 14;10(1):11596. Epub 2020 Jul 14.

Molecular Parasitology and Opportunistic Infections Program, Department of Microbiology, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, Thohoyandou, 0950, South Africa.

Some antibiotics have lost their efficacy over common infections and this has led to the search for new antibiotics and chemically altering existing ones for a better control of infectious diseases. In the present study, Pyrenacantha grandiflora tubers extracts were conjugated with ampicillin, penicillin, vancomycin and silver nanoparticles and their antimicrobial activity was evaluated against Escherichia coli, Staphylococcus aureus and Klebsiella Pneumoniae. The reactions were confirmed by formation of new functional groups that were identified by Fourier transmission infrared spectroscopy (FTIR). Minimum inhibitory concentrations were determined using the microdilution assay. Minimum bactericidal concentrations and the fractional inhibition concentration index were also determined. FTIR analysis indicated different functional group associated with conjugation. The activity of ampicillin was improved when conjugated with silver nanoparticles against K. pneumonia and E. coli. Vancomycin showed improvement of activity when conjugated to silver nanoparticles against K. pneumonia. Penicillin was improved by acetone extracts and vancomycin showed to be more effective when conjugated with silver nanoparticles and water extracts. The conjugation of P. grandiflora with penicillin, ampicillin and vancomycin in the presence of silver nanoparticles improved their biological activities. Therefore, the conjugates are medicinally important and can be used to improve the activity of existing antibiotics.
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http://dx.doi.org/10.1038/s41598-020-68290-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7360584PMC
July 2020

Antimicrobial activity of selected plants against fungal species isolated from South African AIDS patients and their antigonococcal activity.

J Complement Integr Med 2020 Sep 23;17(3). Epub 2020 Sep 23.

PrivateBag X5050, South Africa.

Background Sexually transmitted infections continue to be a major health concern in sub-Saharan Africa where antimicrobial drugs are becoming ineffective due to increasing resistance. Many healthcare seekers in lower socio-economic settings depend on invasive alien plants administered by traditional health practitioners to treat sexually transmitted infections. Methods Roots of selected plants were analysed for phytoconstituents using standard methods. Both the disc diffusion model and microdilution technique were used to determine the inhibition zone and minimum inhibitory concentration (MIC) of plant extracts against six clinical fungal strains and standard strain of Neisseria gonorrhoea. One-way ANOVA was used to find significant differences. Results Different phytoconstituents such as alkaloids, steroids, cardiac glycosides, terpenes, flavonoids, tannins and saponins were qualitatively detected, depending on plant species. Acetone extracted the highest number of phytoconstituents in Senna didymobotrya, while methanol revealed most from Ricinus communis. Senna didymobotrya showed significant inhibition against Candida glabrata, C. krusei, C. parapsilosis and C. tropicalis. Dichloromethane extract of Catharanthus roseus and methanol extract of S. didymobotrya demonstrated excellent MIC values of 0.03 and 0.08 mg/mL, respectively, against C. glabrata. Catharanthus roseus, Opuntia ficus-indica and Ricinus communis demonstrated moderate to good antigonococcal activity, with all exhibiting more than 63% inhibition. Catharanthus roseus had the best antigonococcal activity with a moderate MIC value of 0.63 mg/mL. Conclusion Some of the plant extracts demonstrated potency towards clinically isolated fungal strains and against N. gonorrhoea, which validate the notion that some of the species need further pharmacological studies for isolation and characterisation of active compounds.
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http://dx.doi.org/10.1515/jcim-2019-0087DOI Listing
September 2020

Prevalence and distribution of Entamoeba species in a rural community in northern South Africa.

Food Waterborne Parasitol 2020 Mar 20;18:e00076. Epub 2020 Feb 20.

Medical Laboratory Sciences Department, College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates.

Amoebiasis occurs worldwide and affects about 20-50 million people annually. Stool samples were collected from patients attending different rural clinics in Northern South Africa in the present study. Microscopic examination was performed for the initial detection of parasites. A multiplex PCR protocol based on the small subunit rRNA gene of , , and , was used for the differential detection of the three species (collectively referred to as complex). A total of 170 participants were recruited in the study, with a mean age of 35.9 ± 17.8 years and a median of 37.0 years. The prevalence of species was found to be 34.7% and 33% by PCR and microscopy, respectively. had a prevalence of 4.1%, 14.7% and 15.9%. Of the three species, only was significantly associated with diarrhoea and was more prevalent among HIV patients even in the absence of diarrhoea while the other two were not, although the difference was not significant ( > 0.05). This is the first study in South Africa to describe the prevalence of . was significantly associated with abdominal pains ( = 0.003). Further studies are needed to clarify the role of and in abdominal pain and diarrhoea.
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http://dx.doi.org/10.1016/j.fawpar.2020.e00076DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7058707PMC
March 2020

Prevalence and genetic characterization of in relation to diarrhea in Limpopo and Gauteng provinces, South Africa.

Parasite Epidemiol Control 2020 May 31;9:e00140. Epub 2020 Jan 31.

Deputy Pro Vice Chancellor Academics and Quality, Botho University, Botho Education Park, Kgale, Gaborone, Botswana.

Background: Very few studies have determined the prevalence and assemblage distribution of in South Africa. The present study aimed to ascertain the prevalence of infection and the spread of the various assemblages in two communities in South Africa - Giyani, Limpopo province (rural community) and Pretoria Guateng province (urban community).

Methods: Prevalence was determined by immunological and molecular methods analyzing a total of 516 stool samples collected from patients visiting different health centres in Giyani and Pretoria. For immunological assays, samples were screened by ELISA to detect antigen. Furthermore, a semi nested PCR amplifying the triose phosphate isomerase (tpi) gene was used to differentiate between the two most common human assemblages (A and B).

Findings: Of the 516 participants, 40 (7.75%) were identified as positive by ELISA. A statistically significant correlation was observed between the stool texture and infection (ᵡ = 10.533;  = .005). was significantly associated with watery stool types in females  = .008. Furthermore, a significant association was also noticed between the origin of samples (ᵡ = 9.725;  = .002). No significant correlation between age and gender was noted. Regarding the age groups, most people who were infected were between 3 and 20 years. A statistically significant association was seen ( = .001) with the distribution of the pathogen with the stool type. The prevalence of infection was higher in watery stool samples (71.4%) in Giyani region (rural) whereas in Pretoria, high prevalence was found in loose stool samples (6.2%). Generally, the distribution was statistically significant in the stool type collected for the study ( = .005). Genotyping revealed more assemblage B (17.8%) than assemblage A (1.7%). Furthermore, 21.0% of the samples exhibited single infection while 4.2% had mixed infections. Assemblage B was more common in Giyani than in urban Pretoria.

Conclusions: The study confirms as an important cause of diarrhea in the concerned communities with people in rural areas more at risk compared to those in urban areas with higher prevalence among younger patients. Therefore, health education campaigns should target young age groups.
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http://dx.doi.org/10.1016/j.parepi.2020.e00140DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7016452PMC
May 2020

Protection From Natural Immunity Against Enteric Infections and Etiology-Specific Diarrhea in a Longitudinal Birth Cohort.

J Infect Dis 2020 11;222(11):1858-1868

Division of Infectious Diseases & International Health, University of Virginia, Charlottesville, Virgina, USA.

Background: The degree of protection conferred by natural immunity is unknown for many enteropathogens, but it is important to support the development of enteric vaccines.

Methods: We used the Andersen-Gill extension of the Cox model to estimate the effects of previous infections on the incidence of subsequent subclinical infections and diarrhea in children under 2 using quantitative molecular diagnostics in the MAL-ED cohort. We used cross-pathogen negative control associations to correct bias due to confounding by unmeasured heterogeneity of exposure and susceptibility.

Results: Prior rotavirus infection was associated with a 50% lower hazard (calibrated hazard ratio [cHR], 0.50; 95% confidence interval [CI], 0.41-0.62) of subsequent rotavirus diarrhea. Strong protection was evident against Cryptosporidium diarrhea (cHR, 0.32; 95% CI, 0.20-0.51). There was also protection due to prior infections for norovirus GII (cHR against diarrhea, 0.67; 95% CI, 0.49-0.91), astrovirus (cHR, 0.62; 95% CI, 0.48-0.81), and Shigella (cHR, 0.79; 95% CI, 0.65-0.95). Minimal protection was observed for other bacteria, adenovirus 40/41, and sapovirus.

Conclusions: Natural immunity was generally stronger for the enteric viruses than bacteria, potentially due to less antigenic diversity. Vaccines against major causes of diarrhea may be feasible but likely need to be more immunogenic than natural infection.
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http://dx.doi.org/10.1093/infdis/jiaa031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7653087PMC
November 2020

Distribution and Potential Effects of 17β-Estradiol (E2) on Aeromonas Diversity in Wastewater and Fish Samples.

Pak J Biol Sci 2020 Jan;23(3):278-286

Background And Objective: Recently, there has been evidence for the accumulation of steroid hormones in the water environment with negative consequences on fish and humans. However, there is paucity of information on how the steroid hormones influence the microbial community in environmental waters. The objective of this study was to determine the occurrence of 17β-estradiol (E2) and its potential influence on the diversity of Aeromonas spp.

Materials And Methods: Wastewater samples were obtained from sewage treatment plants in northern South Africa and fish samples were collected from the Nandoni dam. Aeromonas spp. were isolated using microbiological methods and PCR protocols were used for their identification. A commercial Elisa kit was used for measuring the concentration of 17β-estradiol (E2) from the wastewater samples as well as the fish samples.

Results: 17β-estradiol (E2) was found in high concentration in sewage samples varying from 0.32-348.6 pg mL-1 while in fish samples, it ranged from 1.1-73.6 pg mL-1. There was a tendency of samples with high E2 concentrations to have higher diversity of Aeromonas spp., implying that steroid hormones may serve as nutrient for Aeromonas spp. Aeromonas hydrophila was the most prevalent species (71%), followed by A. sobria with (68%).

Conclusion: The presence of Aeromonas spp. in environmental waters and fish that is consumed by the local community poses a serious health concern. The high content of E2 in treated wastewater is of serious concern as well. For the first time, the present study showed a positive impact of E2 on Aeromonas growth.
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http://dx.doi.org/10.3923/pjbs.2020.278.286DOI Listing
January 2020

Determinants of Campylobacter infection and association with growth and enteric inflammation in children under 2 years of age in low-resource settings.

Sci Rep 2019 11 20;9(1):17124. Epub 2019 Nov 20.

Nutrition and Clinical Services Division, icddr,b, Dhaka, Bangladesh.

Campylobacter species infections have been associated with malnutrition and intestinal inflammation among children in low-resource settings. However, it remains unclear whether that association is specific to Campylobacter jejuni/coli. The aim of this study was to assess the association between both all Campylobacter species infections and Campylobacter jejuni/coli infections on growth and enteric inflammation in children aged 1-24 months. We analyzed data from 1715 children followed from birth until 24 months of age in the MAL-ED birth cohort study, including detection of Campylobacter species by enzyme immunoassay and Campylobacter jejuni/coli by quantitative PCR in stool samples. Myeloperoxidase (MPO) concentration in stool, used as a quantitative index of enteric inflammation, was measured. The incidence rate per 100 child-months of infections with Campylobacter jejuni/coli and Campylobacter species during 1-24 month follow up were 17.7 and 29.6 respectively. Female sex of child, shorter duration of exclusive breastfeeding, lower maternal age, mother having less than 3 living children, maternal educational level of <6 years, lack of routine treatment of drinking water, and unimproved sanitation were associated with Campylobacter jejuni/coli infection. The cumulative burden of both Campylobacter jejuni/coli infections and Campylobacter species were associated with poor growth and increased intestinal inflammation.
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http://dx.doi.org/10.1038/s41598-019-53533-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6868199PMC
November 2019

Molecular Subtyping of Blastocystis from Diverse Animals in the United Arab Emirates.

Protist 2019 11 27;170(5):125679. Epub 2019 Aug 27.

Medical Laboratory Sciences Department, College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates. Electronic address:

The contribution of Blastocystis from non-human hosts to zoonotic transmission is only partly known. The objective of this study was to determine the distribution of Blastocystis genetic subtypes in different animal species in United Arab Emirates. A total of 114 stool samples were tested using PCR of the small subunit (SSU) rRNA gene and sequence analysis. Twenty-three Blastocystis-positive samples were identified. The following detection rates were observed: cattle, 22.7%; sheep, 63.6%; rabbits, 33.3%; rodents, 37.5%; reptiles, 21.2%. Four subtypes were identified in this study; ST4, ST10, ST14, and ST17; ST10 was isolated from sheep and cattle, corroborating previous data indicating that these are natural hosts for this subtype. Cases of mixed subtype colonization were also detected. Conspicuously, we found ST14 in rabbits. The discovery of ST17 in a squirrel indicates a novel host for this subtype. Furthermore, the discovery of ST4 in rodents suggests that these may serve as reservoir for human Blastocystis ST4 colonization. Six tortoises and one iguana were positive for Blastocystis. In conclusion, this is the first report of Blastocystis infection in various animals in the UAE. Apart from ST4, no potentially zoonotic subtypes were detected.
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http://dx.doi.org/10.1016/j.protis.2019.125679DOI Listing
November 2019

Prevalence of Virulence Genes in Enteroaggregative Isolates from Young Children from Rural South Africa.

Am J Trop Med Hyg 2019 11;101(5):1027-1033

Department of Microbiology, University of Venda, Thohoyandou, South Africa.

In this study, we report on the prevalence of 19 virulence genes in enteroaggregative (EAEC) isolates from northern South Africa. Stool samples obtained prospectively from 97 children from 1 to 12 months of age were analyzed, and EAEC isolates were confirmed based on the presence of or genes. We investigated 177 enteroaggregative isolates for the prevalence of virulence genes using multiplex polymerase chain reaction. The chromosomal gene was detected at higher frequency (48.0%) compared with (26.0%). The gene encoding the open reading frame was the most prevalent putative virulence trait detected among the isolates (150/177; 84.7%). None of the genes was statistically associated with diarrhea ( > 0.05). Detection rates were higher during 7-12 month of life with an association observed for the gene and the age group 7-12 months ( = 0.04). Winter was the season with the highest detection rates. Our data reveal a high prevalence of , , and in South African EAEC isolates. Specific genes may provide additional markers for the study of disease associations with age and season of sample collection.
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http://dx.doi.org/10.4269/ajtmh.19-0192DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6838558PMC
November 2019

Dataset on preliminary phytochemical analysis and antioxidant activity of selected invasive alien plant species used in the treatment of sexually transmitted infections in Waterberg district, South Africa.

Data Brief 2019 Aug 17;25:104281. Epub 2019 Jul 17.

Department of Microbiology, School of Mathematics and Natural Sciences, University of Venda, Private Bag X5050, Thohoyandou, South Africa.

The current dataset follows the published article [1]. The dataset provides preliminary phytochemical analysis and antioxidant activity of selected invasive alien plant used by Bapedi Traditional Health Practitioners to treat sexually transmitted infections (STIs). It was evident that seven STIs are treated with herbal remedies of the documented plant species. Informational on the medicinal plant uses and the use categories of sexually transmitted infections are presented on table 1. Table 2 shows the yield of plant extracts. Detailed data on phytochemical analysis and antioxidant activity are presented on Fig 1 and 2 respectively. Rf values of separated compounds are provided in Table 3. The data contains both qualitative and quantitative information.
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http://dx.doi.org/10.1016/j.dib.2019.104281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6669344PMC
August 2019

Mechanochemically Activated Aluminosilicate Clay Soils and their Application for Defluoridation and Pathogen Removal from Groundwater.

Int J Environ Res Public Health 2019 02 22;16(4). Epub 2019 Feb 22.

Department of Microbiology, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa.

In this study, aluminosilicate rich clay soils were prepared through mechanochemical activation. The chemical and mineralogical properties were investigated using X-Ray Fluorescence (XRF) and X-ray diffraction (XRD). The functional groups, morphology and surface area were evaluated using Fourier Transform Infra-Red (FTIR), Scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. Batch experiments were used to evaluate its defluoridation efficiency while antibacterial activities were assessed using well diffusion method. Maximum adsorption capacity was found to be 1.87 mg/g with 32% fluoride removal. Fluoride adsorption was found to reduce in the presence of Cl, PO₄ and CO₃ while it increased in the presence of SO₄ and NO₃. Adsorption data fitted well to Freundlich isotherms, hence, confirming heterogeneous multilayer adsorption. Kinetic studies revealed that fluoride adsorption fitted well to pseudo-second order model. The sorption of F onto the clays' surface followed intra-particle diffusion mode. High correlation coefficient indicates that the sorption process was greatly controlled by particle diffusion while it is minimal in pore diffusion model. Antibacterial studies revealed no zone of inhibition for all the activated clays, hence indicating that they are not active against the bacterial strains of used in this study. The results showed activated clays' potential for defluoridation. Its effectiveness in pathogen removal is limited. Hence further modifications of the clays' surfaces are hereby recommended.
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http://dx.doi.org/10.3390/ijerph16040654DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6407019PMC
February 2019

Challenges to Sustainable Safe Drinking Water: A Case Study of Water Quality and Use across Seasons in Rural Communities in Limpopo Province, South Africa.

Water (Basel) 2018 Feb 7;10(2). Epub 2018 Feb 7.

Division of Infectious Diseases & International Health, University of Virginia, Charlottesville, VA 22908, USA;

Consumption of microbial-contaminated water can result in diarrheal illnesses and enteropathy with the heaviest impact upon children below the age of five. We aimed to provide a comprehensive analysis of water quality in a low-resource setting in Limpopo province, South Africa. Surveys were conducted in 405 households in rural communities of Limpopo province to determine their water-use practices, perceptions of water quality, and household water-treatment methods. Drinking water samples were tested from households for microbiological contamination. Water from potential natural sources were tested for physicochemical and microbiological quality in the dry and wet seasons. Most households had their primary water source piped into their yard or used an intermittent public tap. Approximately one third of caregivers perceived that they could get sick from drinking water. All natural water sources tested positive for fecal contamination at some point during each season. The treated municipal supply never tested positive for fecal contamination; however, the treated system does not reach all residents in the valley; furthermore, frequent shutdowns of the treatment systems and intermittent distribution make the treated water unreliable. The increased water quantity in the wet season correlates with increased treated water from municipal taps and a decrease in the average contaminant levels in household water. This research suggests that wet season increases in water quantity result in more treated water in the region and that is reflected in residents' water-use practices.
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http://dx.doi.org/10.3390/w10020159DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6310213PMC
February 2018

Use of quantitative molecular diagnostic methods to assess the aetiology, burden, and clinical characteristics of diarrhoea in children in low-resource settings: a reanalysis of the MAL-ED cohort study.

Lancet Glob Health 2018 12 1;6(12):e1309-e1318. Epub 2018 Oct 1.

Fogarty International Center, National Institutes of Health, Bethesda, MD, USA.

Background: Optimum management of childhood diarrhoea in low-resource settings has been hampered by insufficient data on aetiology, burden, and associated clinical characteristics. We used quantitative diagnostic methods to reassess and refine estimates of diarrhoea aetiology from the Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) cohort study.

Methods: We re-analysed stool specimens from the multisite MAL-ED cohort study of children aged 0-2 years done at eight locations (Dhaka, Bangladesh; Vellore, India; Bhaktapur, Nepal; Naushero Feroze, Pakistan; Venda, South Africa; Haydom, Tanzania; Fortaleza, Brazil; and Loreto, Peru), which included active surveillance for diarrhoea and routine non-diarrhoeal stool collection. We used quantitative PCR to test for 29 enteropathogens, calculated population-level pathogen-specific attributable burdens, derived stringent quantitative cutoffs to identify aetiology for individual episodes, and created aetiology prediction scores using clinical characteristics.

Findings: We analysed 6625 diarrhoeal and 30 968 non-diarrhoeal surveillance stools from 1715 children. Overall, 64·9% of diarrhoea episodes (95% CI 62·6-71·2) could be attributed to an aetiology by quantitative PCR compared with 32·8% (30·8-38·7) using the original study microbiology. Viral diarrhoea (36·4% of overall incidence, 95% CI 33·6-39·5) was more common than bacterial (25·0%, 23·4-28·4) and parasitic diarrhoea (3·5%, 3·0-5·2). Ten pathogens accounted for 95·7% of attributable diarrhoea: Shigella (26·1 attributable episodes per 100 child-years, 95% CI 23·8-29·9), sapovirus (22·8, 18·9-27·5), rotavirus (20·7, 18·8-23·0), adenovirus 40/41 (19·0, 16·8-23·0), enterotoxigenic Escherichia coli (18·8, 16·5-23·8), norovirus (15·4, 13·5-20·1), astrovirus (15·0, 12·0-19·5), Campylobacter jejuni or C coli (12·1, 8·5-17·2), Cryptosporidium (5·8, 4·3-8·3), and typical enteropathogenic E coli (5·4, 2·8-9·3). 86·2% of the attributable incidence for Shigella was non-dysenteric. A prediction score for shigellosis was more accurate (sensitivity 50·4% [95% CI 46·7-54·1], specificity 84·0% [83·0-84·9]) than current guidelines, which recommend treatment only of bloody diarrhoea to cover Shigella (sensitivity 14·5% [95% CI 12·1-17·3], specificity 96·5% [96·0-97·0]).

Interpretation: Quantitative molecular diagnostics improved estimates of pathogen-specific burdens of childhood diarrhoea in the community setting. Viral causes predominated, including a substantial burden of sapovirus; however, Shigella had the highest overall burden with a high incidence in the second year of life. These data could improve the management of diarrhoea in these low-resource settings.

Funding: Bill & Melinda Gates Foundation.
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http://dx.doi.org/10.1016/S2214-109X(18)30349-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6227251PMC
December 2018

Use of quantitative molecular diagnostic methods to investigate the effect of enteropathogen infections on linear growth in children in low-resource settings: longitudinal analysis of results from the MAL-ED cohort study.

Lancet Glob Health 2018 12 1;6(12):e1319-e1328. Epub 2018 Oct 1.

Foundation for the National Institutes of Health, Bethesda, MD, USA.

Background: Enteropathogen infections in early childhood not only cause diarrhoea but contribute to poor growth. We used molecular diagnostics to assess whether particular enteropathogens were associated with linear growth across seven low-resource settings.

Methods: We used quantitative PCR to detect 29 enteropathogens in diarrhoeal and non-diarrhoeal stools collected from children in the first 2 years of life obtained during the Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) multisite cohort study. Length was measured monthly. We estimated associations between aetiology-specific diarrhoea and subclinical enteropathogen infection and quantity and attained length in 3 month intervals, at age 2 and 5 years, and used a longitudinal model to account for temporality and time-dependent confounding.

Findings: Among 1469 children who completed 2 year follow-up, 35 622 stool samples were tested and yielded valid results. Diarrhoeal episodes attributed to bacteria and parasites, but not viruses, were associated with small decreases in length after 3 months and at age 2 years. Substantial decrements in length at 2 years were associated with subclinical, non-diarrhoeal, infection with Shigella (length-for-age Z score [LAZ] reduction -0·14, 95% CI -0·27 to -0·01), enteroaggregative Escherichia coli (-0·21, -0·37 to -0·05), Campylobacter (-0·17, -0·32 to -0·01), and Giardia (-0·17, -0·30 to -0·05). Norovirus, Cryptosporidium, typical enteropathogenic E coli, and Enterocytozoon bieneusi were also associated with small decrements in LAZ. Shigella and E bieneusi were associated with the largest decreases in LAZ per log increase in quantity per g of stool (-0·13 LAZ, 95% CI -0·22 to -0·03 for Shigella; -0·14, -0·26 to -0·02 for E bieneusi). Based on these models, interventions that successfully decrease exposure to Shigella, enteroaggregative E coli, Campylobacter, and Giardia could increase mean length of children by 0·12-0·37 LAZ (0·4-1·2 cm) at the MAL-ED sites.

Interpretation: Subclinical infection and quantity of pathogens, particularly Shigella, enteroaggregative E coli, Campylobacter, and Giardia, had a substantial negative association with linear growth, which was sustained during the first 2 years of life, and in some cases, to 5 years. Successfully reducing exposure to certain pathogens might reduce global stunting.

Funding: Bill & Melinda Gates Foundation.
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http://dx.doi.org/10.1016/S2214-109X(18)30351-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6227248PMC
December 2018

PREVALENCE OF SPP. AMONG ASYMPTOMATIC HEALTHY EXPATRIATE WORKERS IN SHARJAH, UNITED ARAB EMIRATES.

Afr J Infect Dis 2018 18;12(2):7-13. Epub 2018 Jun 18.

University of Venda, Department of Microbiology, Thohoyandou, South Africa.

Background: Epidemiological data on infections in the United Arab Emirates (UAE) is scarce. Therefore, the main objective of this study was to determine the prevalence of species among a community of expatriates in Sharjah, UAE working in different sectors, including the food industry, house maids and other domestic occupations.

Materials And Methods: One hundred and thirty four stool samples were collected from asymptomatic individuals presenting to the Sharjah Municipality Public Health Clinic (SMPHC) for screening of intestinal parasites for work permission purposes between 2009 and 2011. Demographic information such as age, sex, and country of origin was collected. Genomic DNA extracted from the stool samples were tested for species using real-time PCR (qPCR).

Results: Twenty-six individuals (19.4%) were positive for sp. by PCR. The infection rate was found to be highest in Afghan nationals (33%; 3/9) compared with the rest of the study population; yet, no significant association existed between nationality and infection rate. Moreover, no association was observed between infection rate and gender (χ = 2.439; P = 0.118), nor infection rate and age group (χ = 1.219; P = 0.544).

Conclusion: Infection by sp. was common in the study group, and further studies are needed within the native Emirati population before any conclusions can be made about foreigners potentially transmitting the parasite. Furthermore, data provided in this study could help determine its public and veterinary significance particularly in outbreaks in the country.
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http://dx.doi.org/10.21010/ajid.v12i2.2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6085736PMC
June 2018

Epidemiology and Risk Factors for Cryptosporidiosis in Children From 8 Low-income Sites: Results From the MAL-ED Study.

Clin Infect Dis 2018 11;67(11):1660-1669

Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland.

Background: Cryptosporidium species are enteric protozoa that cause significant morbidity and mortality in children worldwide. We characterized the epidemiology of Cryptosporidium in children from 8 resource-limited sites in Africa, Asia, and South America.

Methods: Children were enrolled within 17 days of birth and followed twice weekly for 24 months. Diarrheal and monthly surveillance stool samples were tested for Cryptosporidium by enzyme-linked immunosorbent assay. Socioeconomic data were collected by survey, and anthropometry was measured monthly.

Results: Sixty-five percent (962/1486) of children had a Cryptosporidium infection and 54% (802/1486) had at least 1 Cryptosporidium-associated diarrheal episode. Cryptosporidium diarrhea was more likely to be associated with dehydration (16.5% vs 8.3%, P < .01). Rates of Cryptosporidium diarrhea were highest in the Peru (10.9%) and Pakistan (9.2%) sites. In multivariable regression analysis, overcrowding at home was a significant risk factor for infection in the Bangladesh site (odds ratio, 2.3 [95% confidence interval {CI}, 1.2-4.6]). Multiple linear regression demonstrated a decreased length-for-age z score at 24 months in Cryptosporidium-positive children in the India (β = -.26 [95% CI, -.51 to -.01]) and Bangladesh (β = -.20 [95% CI, -.44 to .05]) sites.

Conclusions: This multicountry cohort study confirmed the association of Cryptosporidium infection with stunting in 2 South Asian sites, highlighting the significance of cryptosporidiosis as a risk factor for poor growth. We observed that the rate, age of onset, and number of repeat infections varied per site; future interventions should be targeted per region to maximize success.
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http://dx.doi.org/10.1093/cid/ciy355DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6233690PMC
November 2018

Enteroaggregative Escherichia coli Subclinical Infection and Coinfections and Impaired Child Growth in the MAL-ED Cohort Study.

J Pediatr Gastroenterol Nutr 2018 02;66(2):325-333

Haydom Lutheran Hospital, Moshi, Tanzania.

Objective: We evaluated the impact of subclinical enteroaggregative Escherichia coli (EAEC) infection alone and in combination with other pathogens in the first 6 months of life on child growth.

Methods: Nondiarrheal samples from 1684 children across 8 Multisite Birth Cohort Study, Malnutrition and Enteric Diseases (MAL-ED) sites in Asia, Africa, and Latin America were tested monthly; more than 90% of children were followed-up twice weekly for the first 6 months of life.

Results: Children with subclinical EAEC infection did not show altered growth between enrollment and 6 months. Conversely, EAEC coinfection with any other pathogen was negatively associated with delta weight-for-length (P < 0.05) and weight-for-age (P > 0.05) z scores between 0 and 6 months. The presence of 2 or more pathogens without EAEC was not significantly associated with delta weight-for-length and weight-for-age. The most frequent EAEC coinfections included Campylobacter spp, heat-labile toxin-producing enterotoxigenic E coli, Cryptosporidium spp, and atypical enteropathogenic E coli. Myeloperoxidase levels were increased with EAEC coinfection (P < 0.05). EAEC pathogen codetection was associated with lower neopterin levels compared to those of no-pathogen control children (P < 0.05). Mothers of children with EAEC coinfections had lower levels of education, poorer hygiene and sanitation, lower socioeconomic status, and lower breast-feeding rates compared to mothers of children in whom no pathogen was detected (P < 0.05).

Conclusions: These data emphasize the public health importance of subclinical EAEC infection in early infancy in association with other pathogens and the need for improved maternal and child care, hygiene, sanitation, and socioeconomic factors.
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http://dx.doi.org/10.1097/MPG.0000000000001717DOI Listing
February 2018

Astrovirus Infection and Diarrhea in 8 Countries.

Pediatrics 2018 01 19;141(1). Epub 2017 Dec 19.

Asociación Benéfica PRISMA, Iquitos, Peru;

Background And Objectives: Astroviruses are important drivers of viral gastroenteritis but remain understudied in community settings and low- and middle-income countries. We present data from 8 countries with high prevalence of diarrhea and undernutrition to describe astrovirus epidemiology and assess evidence for protective immunity among children 0 to 2 years of age.

Methods: We used 25 898 surveillance stools and 7077 diarrheal stools contributed by 2082 children for enteropathogen testing, and longitudinal statistical analysis to describe incidence, risk factors, and protective immunity.

Results: Thirty-five percent of children experienced astrovirus infections. Prevalence in diarrheal stools was 5.6%, and severity exceeded all enteropathogens except rotavirus. Incidence of infection and diarrhea were 2.12 and 0.88 episodes per 100 child-months, respectively. Children with astrovirus infection had 2.30 times the odds of experiencing diarrhea after adjustment for covariates (95% confidence interval [CI], 2.01-2.62; < .001). Undernutrition was a risk factor: odds of infection and diarrhea were reduced by 10% and 13%, respectively, per increase in length-for-age score (infection: odds ratio, 0.90 [95% CI, 0.85-0.96]; < .001; diarrhea: odds ratio, 0.87 [95% CI, 0.79-0.96]; = .006). Some evidence of protective immunity to infection was detected (hazard ratio, 0.84 [95% CI, 0.71-1.00], = .052), although this was heterogeneous between sites and significant in India and Peru.

Conclusions: Astrovirus is an overlooked cause of diarrhea among vulnerable children worldwide. With the evidence presented here, we highlight the need for future research as well as the potential for astrovirus to be a target for vaccine development.
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http://dx.doi.org/10.1542/peds.2017-1326DOI Listing
January 2018

Entamoeba Species in South Africa: Correlations With the Host Microbiome, Parasite Burdens, and First Description of Entamoeba bangladeshi Outside of Asia.

J Infect Dis 2017 12;216(12):1592-1600

Department of Medicine/Division of Infectious Diseases, University of Virginia, Charlottesville.

Background: Diarrhea is frequent in communities without clean water, which include low-income South African populations in Giyani and Pretoria. In these populations, the amount of diarrhea caused by Entamoeba histolytica, inclusive of all ages, sexes, and human immunodeficiency virus status, is uncertain. Infection with E. histolytica can modulate the host microbiota, and a key species indicative of this is the Prevotella copri pathobiont.

Methods: A cross-sectional study of patients attending gastroenterology clinics was conducted to determine the frequency and burden of 4 Entamoeba species and P. copri.

Results: Entamoeba species were present in 27% of patients (129/484), with E. histolytica detected in 8.5% (41), E. dispar in 8% (38), E. bangladeshi in 4.75% (23), and E. moshkovskii in 0%. This is the first description of E. bangladeshi outside Bangladesh. In E. histolytica-positive samples, the levels of both the parasite and P. copri were lower in nondiarrheal samples, validating the results of a study in Bangladesh (P = .0034). By contrast, in E. histolytica-negative samples positive for either of the nonpathogenic species E. dispar or E. bangladeshi, neither P. copri nor Entamoeba levels were linked to gastrointestinal status.

Conclusions: Nonmorphologic identification of this parasite is essential. In South Africa, 3 morphologically identical Entamoeba were common, but only E. histolytica was linked to both disease and changes in the microbiota.
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http://dx.doi.org/10.1093/infdis/jix535DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5853652PMC
December 2017

Epidemiology of enteroaggregative Escherichia coli infections and associated outcomes in the MAL-ED birth cohort.

PLoS Negl Trop Dis 2017 Jul 24;11(7):e0005798. Epub 2017 Jul 24.

Clinical Research Unit and Institute of Biomedicine, Federal University of Ceara, Fortaleza, Brazil.

Background: Enteroaggregative E. coli (EAEC) have been associated with mildly inflammatory diarrhea in outbreaks and in travelers and have been increasingly recognized as enteric pathogens in young children with and without overt diarrhea. We examined the risk factors for EAEC infections and their associations with environmental enteropathy biomarkers and growth outcomes over the first two years of life in eight low-resource settings of the MAL-ED study.

Methods: EAEC infections were detected by PCR gene probes for aatA and aaiC virulence traits in 27,094 non-diarrheal surveillance stools and 7,692 diarrheal stools from 2,092 children in the MAL-ED birth cohort. We identified risk factors for EAEC and estimated the associations of EAEC with diarrhea, enteropathy biomarker concentrations, and both short-term (one to three months) and long-term (to two years of age) growth.

Results: Overall, 9,581 samples (27.5%) were positive for EAEC, and almost all children had at least one detection (94.8%) by two years of age. Exclusive breastfeeding, higher enrollment weight, and macrolide use within the preceding 15 days were protective. Although not associated with diarrhea, EAEC infections were weakly associated with biomarkers of intestinal inflammation and more strongly with reduced length at two years of age (LAZ difference associated with high frequency of EAEC detections: -0.30, 95% CI: -0.44, -0.16).

Conclusions: Asymptomatic EAEC infections were common early in life and were associated with linear growth shortfalls. Associations with intestinal inflammation were small in magnitude, but suggest a pathway for the growth impact. Increasing the duration of exclusive breastfeeding may help prevent these potentially inflammatory infections and reduce the long-term impact of early exposure to EAEC.
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http://dx.doi.org/10.1371/journal.pntd.0005798DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5542697PMC
July 2017

Infant Nutritional Status, Feeding Practices, Enteropathogen Exposure, Socioeconomic Status, and Illness Are Associated with Gut Barrier Function As Assessed by the Lactulose Mannitol Test in the MAL-ED Birth Cohort.

Am J Trop Med Hyg 2017 Jul;97(1):281-290

Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.

The lactulose mannitol (LM) dual sugar permeability test is the most commonly used test of environmental enteropathy in developing countries. However, there is a large but conflicting literature on its association with enteric infection and host nutritional status. We conducted a longitudinal cohort using a single field protocol and comparable laboratory procedures to examine intestinal permeability in multiple, geographically diverse pediatric populations. Using a previously published systematic review to guide the selection of factors potentially associated with LM test results, we examined the relationships between these factors and mucosal breach, represented by percent lactulose excretion; absorptive area, represented by percent mannitol excretion; and gut barrier function, represented by the L/M ratio. A total of 6,602 LM tests were conducted in 1,980 children at 3, 6, 9, and 15 months old; percent lactulose excretion, percent mannitol excretion, and the L/M ratio were expressed as age- and sex-specific normalized values using the Brazil cohort as the reference population. Among the factors considered, recent severe diarrhea, lower socioeconomic status, and recent asymptomatic enteropathogen infections were associated with decreased percent mannitol excretion and higher L/M ratios. Poorer concurrent weight-for-age, infection, and recent breastfeeding were associated with increased percent lactulose excretion and increased L/M ratios. Our results support previously reported associations between the L/M ratio and factors related to child nutritional status and enteropathogen exposure. These results were remarkably consistent across sites and support the hypothesis that the frequency of these exposures in communities living in poverty leads to alterations in gut barrier function.
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http://dx.doi.org/10.4269/ajtmh.16-0830DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5508897PMC
July 2017

PREVALENCE OF IGG AND IGM AND ASSOCIATED RISK FACTORS AMONG HIV-POSITIVE AND HIV-NEGATIVE PATIENTS IN VHEMBE DISTRICT OF SOUTH AFRICA.

Afr J Infect Dis 2017 8;11(2):1-9. Epub 2017 Jun 8.

Molecular Parasitology and Opportunistic Infections Program, Department of Microbiology, School of Mathematical and Natural Sciences, University of Venda, South Africa.

Background: is a zoonotic parasite that has arisen as an important opportunistic infection that causes morbidity and mortality especially in HIV positive patients. This study was carried out to determine the sero-prevalence of (IgG and IgM) and the associated risk factors among HIV positive and negative patients in Northern South Africa.

Materials And Methods: The study was conducted in the Vhembe District in Limpopo province from April 2012 to January 2013. A well-structured questionnaire was used to collect socio-demographic information and possible risk factor information on toxoplasmosis from participants. A total of 161 blood samples of both HIV positive and negative patients visiting the local clinics in the Vhembe district were collected. Serum samples were tested for IgG and IgM against using commercially available ELISA protocol.

Results: The prevalence of IgG was 31.7% while that of IgM was 4.9%. The prevalence of IgG was higher in HIV positive patients (38%) compared to 16.7% among HIV negative patients (p=0.001). IgG antibodies were more common in patients who were not taking ARV's (46.2%) compared to those who were taking ARV's (35.2%) (P<0.001).

Conclusions: The present study has shown a high prevalence of (IgG) among patients attending different HIV clinics in the Vhembe district with no current infections among pregnant women. In addition to the sero-positive status of the patient to HIV, other significant risk factors for toxoplasmosis included high viral load, non-adherence to ARV therapy and age (>25 years).
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http://dx.doi.org/10.21010/ajid.v11i2.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5476807PMC
June 2017

Age and Sex Normalization of Intestinal Permeability Measures for the Improved Assessment of Enteropathy in Infancy and Early Childhood: Results From the MAL-ED Study.

J Pediatr Gastroenterol Nutr 2017 07;65(1):31-39

*Department of International Health, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore †Fogarty International Center/National Institutes of Health, Bethesda, MD ‡Department of Global Community Health and Behavioral Sciences, Tulane University, New Orleans, LA §University of Virginia, Charlottesville, VA ¶ICDDR, b, Dhaka, Bangladesh ||Christian Medical College, Vellore, India **University of Venda, Thohoyandou, South Africa ††Center of Excellence in Women and Child Health, the Aga Khan University, Karachi, Pakistan ‡‡Haydom Lutheran Hospital, Haydom, Tanzania §§Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN ¶¶Universidade Federal do Ceara, Fortaleza, Brazil ||||A.B. PRISMA, Iquitos, Peru ***Walter Reed/AFRIMS Research Unit, Kathmandu, Nepal †††Immunochemical Core Laboratory, Mayo Clinic, Rochester, MN ‡‡‡Pain Consultants of Oregon, Eugene, OR §§§Foundation for the NIH, Bethesda, MD.

Objectives: The aim of the study was to describe changes in intestinal permeability in early childhood in diverse epidemiologic settings.

Methods: In a birth cohort study, the lactulose:mannitol (L:M) test was administered to 1980 children at 4 time points in the first 24 months of life in 8 countries. Data from the Brazil site with an incidence of diarrhea similar to that seen in the United States and no growth faltering was used as an internal study reference to derive age- and sex-specific z scores for mannitol and lactulose recoveries and the L:M ratio.

Results: A total of 6602 tests demonstrated mannitol recovery, lactulose recovery, and the L:M ratio were associated with country, sex, and age. There was heterogeneity in the recovery of both probes between sites with mean mannitol recovery ranging for 1.34% to 5.88%, lactulose recovery of 0.19% to 0.58%, and L:M ratios 0.10 to 0.17 in boys of 3 months of age across different sites. We observed strong sex-specific differences in both mannitol and lactulose recovery, with boys having higher recovery of both probes. Alterations in intestinal barrier function increased in most sites from 3 to 9 months of age and plateaued or diminished from 9 to 15 months of age.

Conclusions: Alterations in recovery of the probes differ markedly in different epidemiologic contexts in children living in the developing world. The rate of change in the L:M-z ratio was most rapid and consistently disparate from the reference standard in the period between 6 and 9 months of age, suggesting that this is a critical period of physiologic impact of enteropathy in these populations.
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http://dx.doi.org/10.1097/MPG.0000000000001610DOI Listing
July 2017