Publications by authors named "Mohammed El-Mowafy"

17 Publications

  • Page 1 of 1

Metabolic Influences of Gut Microbiota Dysbiosis on Inflammatory Bowel Disease.

Front Physiol 2021 27;12:715506. Epub 2021 Sep 27.

Faculty of Health Sciences, School of Nutrition Sciences, University of Ottawa, Ottawa, ON, Canada.

Inflammatory bowel diseases (IBD) are chronic medical disorders characterized by recurrent gastrointestinal inflammation. While the etiology of IBD is still unknown, the pathogenesis of the disease results from perturbations in both gut microbiota and the host immune system. Gut microbiota dysbiosis in IBD is characterized by depleted diversity, reduced abundance of short chain fatty acids (SCFAs) producers and enriched proinflammatory microbes such as adherent/invasive and HS producers. This dysbiosis may contribute to the inflammation through affecting either the immune system or a metabolic pathway. The immune responses to gut microbiota in IBD are extensively discussed. In this review, we highlight the main metabolic pathways that regulate the host-microbiota interaction. We also discuss the reported findings indicating that the microbial dysbiosis during IBD has a potential metabolic impact on colonocytes and this may underlie the disease progression. Moreover, we present the host metabolic defectiveness that adds to the impact of symbiont dysbiosis on the disease progression. This will raise the possibility that gut microbiota dysbiosis associated with IBD results in functional perturbations of host-microbiota interactions, and consequently modulates the disease development. Finally, we shed light on the possible therapeutic approaches of IBD through targeting gut microbiome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fphys.2021.715506DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8502967PMC
September 2021

Ingestion of mannose ameliorates thioacetamide-induced intrahepatic oxidative stress, inflammation and fibrosis in rats.

Life Sci 2021 Oct 9:120040. Epub 2021 Oct 9.

Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt. Electronic address:

Background And Aims: The monosaccharide mannose has gained recent interest for its beneficial effect against certain inflammatory disorders. Nevertheless, the influence of mannose on experimentally-induced liver fibrosis and the ensued inflammation is still not fully clear to date.

Main Methods: The current study investigated the outcomes of treating rats with mannose (0.2 ml of 20% w/v, oral gavage) 30 min before the twice weekly intoxication with thioacetamide (TAA) (200 mg/kg, intraperitoneal) for a total period of 8 weeks.

Key Findings: The data indicated that mannose markedly dampened TAA-induced liver fibrosis, as indicated by lowering the fibrotic bridges shown by Masson's trichrome staining. This effect was consistent with reducing TAA-induced hepatocellular injury, as evidenced biochemically (serum ALT and AST activities) and pathologically (necroinflammation score). These hepatoprotective effects mediated by mannose were attributed to i) reversing TAA-induced rise in malondialdehyde (MDA) and decrease in reduced glutathione (GSH) expressions in the liver, ii) limiting TAA-induced release of the proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), iii) impairing TAA-induced activation of hepatic stellate cells by downregulating α-smooth muscle actin expression (α-SMA) and, and importantly, iv) dampening TAA-induced fibrogenesis driven by transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF).

Significance: Mannose may be an auspicious candidate for preventing oxidative stress, inflammation and fibrogenesis in the liver.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.lfs.2021.120040DOI Listing
October 2021

Antimicrobial resistance and virulence characteristics in ERIC-PCR typed biofilm forming isolates of P. aeruginosa.

Microb Pathog 2021 Sep 11;158:105042. Epub 2021 Jun 11.

Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt.

Pseudomonas aeruginosa is a serious pathogen particularly in immunocompromised patients. In this work, 103 clinical isolates of P. aeruginosa were collected and classified into weak, moderate, and strong biofilm producers according to their biofilm forming abilities via tissue culture plate method. The antimicrobial resistance and the presence of different virulence genes were investigated via disc diffusion method and polymerase chain reaction respectively. Moreover, ERIC-PCR typing was performed to investigate the genetic diversity among the clinical isolates. No significant correlation was observed between biofilm formation and resistance to each antimicrobial agent. Similar observation was detected concerning the multidrug resistance and biofilm formation. Regarding virulence genes, algD gene was harbored by all isolates (100%). Only pelA and phzM were significantly prevalent in strong biofilm producers. Additionally, the mean virulence score was higher in strong biofilm producers (9.33) than moderate (8.62) and weak (7) biofilm producers. Moreover, there was a significant correlation between the overall virulence score of the isolates and its ability to form biofilm. ERIC-PCR genotyping revealed the presence of 99 different ERIC patterns based on 70% similarity, and the different ERIC patterns were categorized into 8 clusters. 100% similarity indicates the possibility of cross-colonization in P. aeruginosa infections.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.micpath.2021.105042DOI Listing
September 2021

Natural variability in surface antigen and reverse transcriptase domain of hepatitis B virus in treatment-naïve chronic HBV-infected Egyptian patients.

Virus Res 2021 Sep 6;302:198422. Epub 2021 Apr 6.

Microbiology and Immunology Department, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt. Electronic address:

Hepatitis B virus (HBV) infection is a serious health problem not only in Egypt, but also worldwide. We collected 57 serum samples from treatment-naïve chronic HBV-infected Egyptians. The DNA segment encoding HBV surface antigen (HBsAg) and reverse transcriptase (RT) domain was partially sequenced. Our data revealed that all viral isolates belonged to genotype D with ayw2 as the predominant serotype (89 %). Regarding HBsAg, 45 substitutions were detected in the collected isolates. Eleven substitutions were found in the major hydrophilic region, including two novel ones (M103T and G130E) that were not correlated before with genotype D. Additionally, 11 occult samples (19 %) were detected, in which the predominant mutations of HBsAg were S143L (7 samples) followed by D144A and T125M (4 samples each). Concerning the RT domain, 26 isolates (45 %) harbored 19 natural mutations that were reported to be associated with antiviral resistance. Eleven different mutations were not correlated previously with genotype D. The most predominant mutation was Y124H (47 samples, 82 %). Interestingly, such mutation was detected in 91 % of the previous reported sequences of HBV isolates collected in Egypt (157 sequences). Furthermore, our study illustrated the presence of viral quasispecies in the HBsAg (10 samples, 17.5 %) and RT domain (9 samples, 15.7 %). In conclusion, we elucidated the presence of natural substitutions in HBsAg and RT domain of HBV isolates obtained from treatment-naïve chronic HBV-infected Egyptian patients. Additionally, we detected viral quasispecies and revealed Y124H as a characteristic substitution in the RT domain for HBV isolates in Egypt. Moreover, novel substitutions in HBsAg and RT domain were reported with genotype D.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.virusres.2021.198422DOI Listing
September 2021

Serum Soluble Fibrinogen-Like Protein 2 Represents a Novel Biomarker for Differentiation Between Acute and Chronic Egyptian Hepatitis B Virus-Infected Patients.

J Interferon Cytokine Res 2021 02;41(2):52-59

Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.

Hepatitis B virus (HBV) infection is considered as one of the most serious public health problems worldwide including Egypt. Soluble fibrinogen-like protein 2 (sFGL2) is a well-known immunomodulator that is produced by the T cells and has a strong inhibitory effect on the proliferation of T cells and maturation of dendritic cells (DC). In the current study, serum levels of sFGL2 were assessed utilizing enzyme-linked immunosorbent assay (ELISA) technique among 20 acute HBV-infected patients, 55 chronic HBV-infected patients and 15 healthy individuals. In addition, serum levels of soluble FAS ligand (sFASL), soluble FAS receptor (sFAS) as well as interferon-γ (IFN-γ) were assessed and correlated to the levels of sFGL2. According to our results, serum levels of sFGL2 were significantly higher in the acute HBV-infected patients than in the chronic HBV-infected patients and healthy individuals. On the other hand, the serum levels of sFASL, sFAS and IFN-γ were significantly higher in the chronic than in acute HBV-infected patients. Also, serum sFGL2 levels were negatively correlated with the serum levels of sFASL, sFAS, IFN-γ and albumin as well as hemoglobin concentration. Furthermore, serum sFGL2 levels were positively correlated with the activities of ALT and AST and total bilirubin levels in serum. Thus, the current work highlights the possibility of utilizing serum sFGL2 level as a novel biomarker for the differentiation between acute and chronic Egyptian HBV-infected patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/jir.2020.0118DOI Listing
February 2021

Changes of Gut-Microbiota-Liver Axis in Hepatitis C Virus Infection.

Biology (Basel) 2021 Jan 13;10(1). Epub 2021 Jan 13.

Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.

The gut-liver-axis is a bidirectional coordination between the gut, including microbial residents, the gut microbiota, from one side and the liver on the other side. Any disturbance in this crosstalk may lead to a disease status that impacts the functionality of both the gut and the liver. A major cause of liver disorders is hepatitis C virus (HCV) infection that has been illustrated to be associated with gut microbiota dysbiosis at different stages of the disease progression. This dysbiosis may start a cycle of inflammation and metabolic disturbance that impacts the gut and liver health and contributes to the disease progression. This review discusses the latest literature addressing this interplay between the gut microbiota and the liver in HCV infection from both directions. Additionally, we highlight the contribution of gut microbiota to the metabolism of antivirals used in HCV treatment regimens and the impact of these medications on the microbiota composition. This review shed light on the potential of the gut microbiota manipulation as an alternative therapeutic approach to control the liver complications post HCV infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/biology10010055DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7828638PMC
January 2021

Exercise-induced downregulation of serum interleukin-6 and tumor necrosis factor-alpha in Egyptian handball players.

Saudi J Biol Sci 2021 Jan 5;28(1):724-730. Epub 2020 Nov 5.

Microbiology & Immunology Department, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.

Muscles of candidates work at various grades of intensity during handball exercises according to the pace of exercise. The movement pattern involves large number of contractions, feints, dodges and numerous changes in movements, all of which are highly responsible for changes in trainer's organs, including the immune system. In this study, inflammatory mediators involving interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) in serum of 18 Egyptian male handball players, selected from Tanta club handball under 21 year's old team, were analyzed. The analysis was established on samples collected just before and immediately after intermediate reasonable exercise via enzyme linked immunosorbent assay (ELISA). Moreover, white blood cells (WBCs) count and other hematological markers including hemoglobin %, hematocrit value, and platelet count were assessed. Our results demonstrated a significant decrease in the levels of IL-6 and TNF-α after exercise compared to those before exercise. This was coupled with an increase in WBCs and platelets count. It is also noteworthy that there was a significant positive correlation between serum levels of IL-6 and TNF-α in the study subjects coupled with a significant negative correlation between IL-6 and WBCs after the exercise. Therefore, it is concluded that intermediate reasonable exercises result in decreased levels of IL-6 and TNF-α, which result in decreasing of the inflammation and help in healing and rapid recovery of muscles of the candidates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.sjbs.2020.10.065DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7783837PMC
January 2021

Alterations of the Treatment-Naive Gut Microbiome in Newly Diagnosed Hepatitis C Virus Infection.

ACS Infect Dis 2021 05 29;7(5):1059-1068. Epub 2020 Oct 29.

Faculty of Health Sciences, School of Nutrition Sciences, University of Ottawa, Ottawa, Ontario K1H8M5, Canada.

Gut microbiota dysbiosis has been linked to many heath disorders including hepatitis C virus (HCV) infection. However, profiles of the gut microbiota alterations in HCV are inconsistent in the literature and are affected by the treatment regimens. Using samples collected prior to treatment from newly diagnosed patients, we characterized the gut microbiota structure in HCV patients as compared to healthy controls. Treatment-naive HCV microbiota showed increased diversity, an increased abundance of , , , , and Ruminococcaceae, and a lower abundance of , , , , , Enterobacteriaceae, Erysipelotrichaceae, Rikenellaceae, and . Predicted community metagenomic functions showed a depletion of carbohydrate and lipid metabolism in HCV microbiota along with perturbations of amino acid metabolism. Receiver-operating characteristic analysis identified five disease-specific operational taxonomic units (OTUs) as potential biomarkers of HCV infections. Collectively, our findings reveal the alteration of gut microbiota in treatment naive HCV patients and suggest that gut microbiota may hold diagnostic promise in HCV infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsinfecdis.0c00432DOI Listing
May 2021

Diagnostic and prognostic value of hematological and immunological markers in COVID-19 infection: A meta-analysis of 6320 patients.

PLoS One 2020 21;15(8):e0238160. Epub 2020 Aug 21.

Division of Endocrine and Oncologic Surgery, Department of Surgery, Tulane University, School of Medicine, New Orleans, Los Angeles, United States of America.

Objective: Evidence-based characterization of the diagnostic and prognostic value of the hematological and immunological markers related to the epidemic of Coronavirus Disease 2019 (COVID-19) is critical to understand the clinical course of the infection and to assess in development and validation of biomarkers.

Methods: Based on systematic search in Web of Science, PubMed, Scopus, and Science Direct up to April 22, 2020, a total of 52 eligible articles with 6,320 laboratory-confirmed COVID-19 cohorts were included. Pairwise comparison between severe versus mild disease, Intensive Care Unit (ICU) versus general ward admission and expired versus survivors were performed for 36 laboratory parameters. The pooled standardized mean difference (SMD) and 95% confidence intervals (CI) were calculated using the DerSimonian Laird method/random effects model and converted to the Odds ratio (OR). The decision tree algorithm was employed to identify the key risk factor(s) attributed to severe COVID-19 disease.

Results: Cohorts with elevated levels of white blood cells (WBCs) (OR = 1.75), neutrophil count (OR = 2.62), D-dimer (OR = 3.97), prolonged prothrombin time (PT) (OR = 1.82), fibrinogen (OR = 3.14), erythrocyte sedimentation rate (OR = 1.60), procalcitonin (OR = 4.76), IL-6 (OR = 2.10), and IL-10 (OR = 4.93) had higher odds of progression to severe phenotype. Decision tree model (sensitivity = 100%, specificity = 81%) showed the high performance of neutrophil count at a cut-off value of more than 3.74x109/L for identifying patients at high risk of severe COVID-19. Likewise, ICU admission was associated with higher levels of WBCs (OR = 5.21), neutrophils (OR = 6.25), D-dimer (OR = 4.19), and prolonged PT (OR = 2.18). Patients with high IL-6 (OR = 13.87), CRP (OR = 7.09), D-dimer (OR = 6.36), and neutrophils (OR = 6.25) had the highest likelihood of mortality.

Conclusions: Several hematological and immunological markers, in particular neutrophilic count, could be helpful to be included within the routine panel for COVID-19 infection evaluation to ensure risk stratification and effective management.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0238160PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7446892PMC
September 2020

Association of cardiac biomarkers and comorbidities with increased mortality, severity, and cardiac injury in COVID-19 patients: A meta-regression and decision tree analysis.

J Med Virol 2020 11 6;92(11):2473-2488. Epub 2020 Jul 6.

Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.

Background: Coronavirus disease-2019 (COVID-19) has a deleterious effect on several systems, including the cardiovascular system. We aim to systematically explore the association of COVID-19 severity and mortality rate with the history of cardiovascular diseases and/or other comorbidities and cardiac injury laboratory markers.

Methods: The standardized mean difference (SMD) or odds ratio (OR) and 95% confidence intervals (CIs) were applied to estimate pooled results from the 56 studies. The prognostic performance of cardiac markers for predicting adverse outcomes and to select the best cutoff threshold was estimated by receiver operating characteristic curve analysis. Decision tree analysis by combining cardiac markers with demographic and clinical features was applied to predict mortality and severity in patients with COVID-19.

Results: A meta-analysis of 17 794 patients showed patients with high cardiac troponin I (OR = 5.22, 95% CI = 3.73-7.31, P < .001) and aspartate aminotransferase (AST) levels (OR = 3.64, 95% CI = 2.84-4.66, P < .001) were more likely to develop adverse outcomes. High troponin I more than 13.75 ng/L combined with either advanced age more than 60 years or elevated AST level more than 27.72 U/L was the best model to predict poor outcomes.

Conclusions: COVID-19 severity and mortality are complicated by myocardial injury. Assessment of cardiac injury biomarkers may improve the identification of those patients at the highest risk and potentially lead to improved therapeutic approaches.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jmv.26166DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7307124PMC
November 2020

Effects of Lysozyme, Proteinase K, and Cephalosporins on Biofilm Formation by Clinical Isolates of .

Interdiscip Perspect Infect Dis 2020 8;2020:6156720. Epub 2020 Feb 8.

Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt.

is an opportunistic pathogen that can form biofilms, which confer resistance to immune clearance and antibacterial treatment. Therefore, effective strategies to prevent biofilm formation are warranted. Here, 103 . clinical isolates were quantitatively screened for biofilm formation ability via the tissue culture plate method. The effects of lysozyme (hydrolytic enzyme) and proteinase K (protease) on biofilm formation were evaluated at different concentrations. Lysozyme (30 g/mL), but not proteinase K, significantly inhibited biofilm formation (19% inhibition). Treatment of 24-hour-old biofilms of . isolates with 50 times the minimum inhibitory concentrations (MICs) of ceftazidime and cefepime significantly decreased the biofilm mass by 32.8% and 44%, respectively. Moreover, the exposure of 24-hour-old biofilms of . isolates to lysozyme (30 g/mL) and 50 times MICs of ceftazidime or cefepime resulted in a significant reduction in biofilm mass as compared with the exposure to lysozyme or either antibacterial agent alone. The best antibiofilm effect (49.3%) was observed with the combination of lysozyme (30 g/mL) and 50 times MIC of cefepime. The promising antibiofilm activity observed after treatment with 50 times MIC of ceftazidime or cefepime alone or in combination with lysozyme (30 g/mL) is indicative of a novel strategy to eradicate pseudomonal biofilms in intravascular devices and contact lenses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2020/6156720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7031717PMC
February 2020

Correlation of Serum Soluble Fibrinogen-Like Protein 2 with Soluble FAS Ligand and Interferon Gamma in Egyptian Hepatitis C Virus-Infected Patients and Hepatocellular Carcinoma Patients.

J Interferon Cytokine Res 2017 08 13;37(8):342-347. Epub 2017 Jun 13.

3 Department of Tropical Medicine, Faculty of Medicine, Mansoura University , Mansoura, Egypt .

Infection with hepatitis C virus (HCV) remains one of the serious human diseases worldwide, especially in Egypt, which can lead to cirrhosis or hepatocellular carcinoma (HCC). However, the exact molecular mechanism of HCC progress in HCV-infected patients remains unclear. Soluble fibrinogen-like protein 2 (sFGL2) is a modulator of the immune response that is secreted by T cells and inhibits maturation of dendritic cells and T cell proliferation. In the current study, serum sFGL2 levels were analyzed by enzyme-linked immunosorbent assay (ELISA) technique in 30 chronic HCV-infected patients (HCV group), 30 chronic HCV-infected patients with HCC (HCC group), and 12 healthy individuals (control group). Moreover, serum levels of soluble FAS ligand (sFASL) and interferon gamma (IFN-γ) were analyzed and correlated with sFGL2 levels. According to our results, serum sFGL2 levels were significantly elevated in all patients with chronic HCV infection. However, HCC patients showed lower sFGL2 levels than HCV-infected patients without HCC incidence. In addition, serum sFASL levels were significantly elevated in both HCV and HCC groups, whereas serum IFN-γ levels were only elevated in the HCC group. Interestingly, sFGL2 correlated positively with serum total bilirubin level and negatively with serum levels of sFASL, IFN-γ, and albumin in HCV and HCC groups. Thus, conclusively, sFGL2 level increases in Egyptian HCV-infected and HCC patients. Taken together, the current work may open future possibility of designing new treatment strategies for HCV infection targeting sFGL2 and its immunosuppressive effect.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/jir.2016.0128DOI Listing
August 2017

Molecular analysis of Hepatitis B virus sub-genotypes and incidence of preS1/preS2 region mutations in HBV-infected Egyptian patients from Mansoura.

J Med Virol 2017 09 23;89(9):1559-1566. Epub 2017 May 23.

Faculty of Medicine, Department of Tropical Medicine, Mansoura University, Mansoura, Egypt.

Hepatitis B virus (HBV) is one of the major causes of viral hepatitis worldwide. Despite the prevalence of HBV infection in Egypt, few studies have focused on sub-genotyping of the virus. Moreover, no studies are available regarding the mutational analysis of the preS1/preS2 region of the viral genome, or its impact on hepatocellular carcinoma (HCC) development in Egypt. In this study, we have analyzed the sub-genotypes and incidence of mutations in the preS1/preS2 region of HBV present in HBV-infected patients, from Mansoura city (located in the center of Nile Delta region of Egypt), via partial sequencing of this specific region. Moreover, we have investigated the impact of these mutations on HCC development by measuring serum alpha fetoprotein (AFP) level and abdominal ultrasound examination of the HBV-infected patients. According to our results, all samples were genotype D in which sub-genotype D1 was predominant. In addition, the results revealed mutations in the preS1/preS2 region, which could result in either immature preS1 protein or completely inhibit the translation of the preS2 protein. However, there was no incidence of HCC development in patients infected with mutated HBV in the preS1/preS2 region. In summary, for the first time our work has proved the predominance of sub-genotype D1 among HBV-infected Egyptian patients in Mansoura city, Nile Delta region, Egypt, and incidence of mutations in the preS1/preS2 region of HBV genome. This current study opens up research opportunities to discuss the impact of HBV mutations on the development of HCC in Egypt.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jmv.24828DOI Listing
September 2017

Emergence of Multidrug-Resistant New Delhi Metallo-β-Lactamase-1-Producing Klebsiella pneumoniae in Egypt.

Microb Drug Resist 2017 Jun 30;23(4):480-487. Epub 2016 Aug 30.

2 Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University , Mansoura, Egypt .

Despite expansion of the New Delhi metallo-β-lactamase-1 (NDM-1) worldwide, the incident of outbreaks regarding Egypt is still uncommon. In this survey, we denounce the emanation of multidrug-resistant NDM-1-producing Klebsiella pneumoniae in Egypt. We have reclaimed 46 unrepeatable carbapenem-resistant K. pneumoniae isolates at El-demerdash hospital, Ain Shams University, Cairo, Egypt. All the isolates showed a decreased sensitivity to imipenem and meropenem via the disc diffusion method. Among the isolates, 10 were proven as NDM-1 producers by utilizing the phenotypic methods (modified Hodge test and EDTA synergistic test) and specific PCR detection of NDM-1 encoding gene, bla. The isolates hosting the bla showed an elevated resistance to several classes of β-lactam and non β-lactam antibiotics. All bla-harboring isolates have showed positivity for one or more other plasmid-mediated bla genes; in addition, the isolates carried class 1 integron. Enterobacterial repetitive intergenic consensus (ERIC)-PCR results revealed that majority of the isolates, including the NDM-1 producers, are unrelated to each other. This highlights the danger of horizontal transfer of plasmids encoding for such carbapenemases, including NDM-1, between the isolates of K. pneumoniae. In summary, this study has confirmed the incidence of bla together with other bla genes among the K. pneumoniae isolates in Egypt. Control and prevention of infection can be achieved through early detection of resistance genes among bacterial isolates; through limiting the dispersal of these organisms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/mdr.2016.0003DOI Listing
June 2017

Effect of Tyrosol and Farnesol on Virulence and Antibiotic Resistance of Clinical Isolates of Pseudomonas aeruginosa.

Biomed Res Int 2015 29;2015:456463. Epub 2015 Dec 29.

Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.

Mixed-species biofilms could create a protected environment that allows for survival to external antimicrobials and allows different bacterial-fungal interactions. Pseudomonas aeruginosa-Candida albicans coexistence is an example for such mixed-species community. Numerous reports demonstrated how P. aeruginosa or its metabolites could influence the growth, morphogenesis, and virulence of C. albicans. In this study, we investigated how the C. albicans quorum sensing compounds, tyrosol and farnesol, might affect Egyptian clinical isolates of P. aeruginosa regarding growth, antibiotic sensitivity, and virulence. We could demonstrate that tyrosol possesses an antibacterial activity against P. aeruginosa (10 µM inhibited more than 50% of growth after 16 h cultivation). Moreover, we could show for the first time that tyrosol strongly inhibits the production of the virulence factors hemolysin and protease in P. aeruginosa, whereas farnesol inhibits, to lower extent, hemolysin production in this bacterial pathogen. Cumulatively, tyrosol is expected to strongly affect P. aeruginosa in mixed microbial biofilm.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2015/456463DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4710896PMC
October 2016

Deletion of the HAMP domains from the histidine kinase CaNik1p of Candida albicans or treatment with fungicides activates the MAP kinase Hog1p in S. cerevisiae transformants.

BMC Microbiol 2013 Sep 17;13:209. Epub 2013 Sep 17.

AG Biological Systems Analysis, Helmholtz Centre for Infection Research (HZI), Inhoffenstr, 7, 38124 Braunschweig, Germany.

Background: Microorganisms use two-component signal transduction (TCST) systems to regulate the response of the organism to changes of environmental conditions. Such systems are absent from mammalian cells and are thus of interest as drug targets. Fungal TCST systems are usually composed of a hybrid histidine kinase, comprising the histidine kinase (HisKA) domain and a receiver domain, a histidine phosphotransfer protein and a response regulator. Among the 11 groups of fungal histidine kinases, group III histidine kinases are of particular relevance as they are essential for the activity of different groups of fungicides. A characteristic feature is the N-terminal amino acid repeat domain comprising multiple HAMP domains, of which the function is still largely unknown. In Candida albicans, a fungal human pathogen, three histidine kinases were identified, of which CaNik1p is a group III histidine kinase. Heterologous expression of this protein in Sacchromyces cerevisiae conferred susceptibility to different fungicides. Fungicide activity was associated with phosphorylation of the mitogen activated protein kinase Hog1p.

Results: We have constructed mutated versions of CaNik1p, from which either all HAMP domains were deleted (CaNik1pΔHAMP) or in which the histidine kinase or the receiver domains were not-functional. Expression of CaNIK1ΔHAMP in S. cerevisiae led to severe growth inhibition. Normal growth could be restored by either replacing the phosphate-accepting histidine residue in CaNik1pΔHAMP or by expressing CaNIK1ΔHAMP in S. cerevisiae mutants, in which single genes encoding several components of the HOG pathway were deleted. Expression of proteins with non-functional histidine kinase or receiver domains resulted in complete loss of susceptibility to antifungals, such as fludioxonil. Conditions leading to growth inhibition of transformants also led to phosphorylation of the MAP kinase Hog1p.

Conclusion: Our results show that functional histidine kinase and receiver domains of CaNik1p were essential for antifungal susceptibility and for activation of the Hog1p. Moreover, for the first time we show that deletion of all HAMP domains from CaNik1p led to activation of Hog1p without an external stimulus. This phenotype was similar to the effects obtained upon treatment with fungicides, as in both cases growth inhibition correlated with Hog1p activation and was dependent on the functionality of the conserved phosphate-accepting histidine residue.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1471-2180-13-209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3848655PMC
September 2013

A novel functional assay for fungal histidine kinases group III reveals the role of HAMP domains for fungicide sensitivity.

J Biotechnol 2012 Jan 22;157(1):268-77. Epub 2011 Sep 22.

Helmholtz Centre for Infection Research, Department of Biological Systems Analysis, Inhoffenstr.7, 38124 Braunschweig, Germany.

Signal transduction systems comprising histidine kinases are suggested as new molecular targets of antibiotics. The important human fungal pathogen Candida albicans possesses three histidine kinases, one of which is the type III histidine kinase CaNik1, which activates the MAP kinase Hog1. We established a screening system for inhibitors of this class of histidine kinases by functional expression of the CaNIK1 gene in S. cerevisiae. This transformant was susceptible to fungicides to which the wild type strain was resistant, such as fludioxonil and ambruticin. Growth inhibition correlated with phosphorylation of Hog1 and was dependent on an intact Hog1 pathway. At the N-terminus the histidine kinase CaNik1 has four amino acid repeats of 92 amino acids each and one truncated repeat of 72 amino acids. Within these repeats we identified 9 HAMP domains with a paired structure. We constructed mutants in which one or two pairs of these domains were deleted. S. cerevisiae transformants expressing the full-length CaNIK1 showed the highest sensitivity to the fungicides, any truncation reduced the susceptibility of the transformants to the fungicides. This indicates that the HAMP domains are decisive for the mode of action of the antifungal compounds.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jbiotec.2011.09.017DOI Listing
January 2012
-->