Publications by authors named "Azar Dokht Khosravi"

41 Publications

Investigation of the , , , , and efflux pump genes expression among multidrug-resistant clinical isolates.

Heliyon 2021 Jul 12;7(7):e07566. Epub 2021 Jul 12.

Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Background: Different resistance mechanisms for multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) have been reported. Although mutations in target genes are the main cause of drug resistance, efflux pumps (Eps) also play an important role in this process. Here, we investigated the overexpression of five putative EP genes plus gene mutations in MDR-TB clinical isolates.

Methods: A total of 27 (Mtb) clinical isolates including, 22 MDR and 5 sensitive isolates were analyzed. Minimum inhibitory concentrations (MIC) were determined in the absence and presence of efflux inhibitor. The expression level of 5 EP genes (, , , , ) was investigated by quantitative real time PCR (RT-qPCR). DNA sequencing of , , and promoter was done.

Results: Among the 22 MDR-TB isolates, 13 (59.1%) showed significant overexpression (>4-fold) for at least one EP gene. The expression levels of 5 genes were significantly higher (P < 0.05) in MDR-TB isolates than sensitive isolates. The (22.7%), and (18.2%) were found to be the most commonly overexpressed EPs. The observed MICs were as follows: RIF (2 to >128 μg/ml) and INH (2-32 μg/ml). After efflux pump inhibitor exposure, 10/22 (45.45%) isolates showed a decrease in MIC of INH, and 17/22 (77.27%) isolates showed a decrease in MIC of RIF. Of the isolates that overexpressed, 4 isolates lacked mutation in , , and genes and 10 ones lacked mutation in and .

Conclusion: The results showed that overexpression of EP genes in Mtb isolates, besides target gene mutations can contribute to the development of MDR phenotype.
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http://dx.doi.org/10.1016/j.heliyon.2021.e07566DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8318855PMC
July 2021

Genotypic and phenotypic prevalence of Nocardia species in Iran: First systematic review and meta-analysis of data accumulated over years 1992-2021.

PLoS One 2021 22;16(7):e0254840. Epub 2021 Jul 22.

Pain Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Background: Nocardia species belong to the aerobic actinomycetes group of bacteria which are gram-positive and partially acid-fast Bacilli. These bacteria may sometimes be associated with nosocomial infections. Nocardia diseases are not required to be reported to public health authorities in Iran. Hence, the present study was designed to determine the prevalence of human Nocardia spp. in Iran by using a systematic review and meta-analysis according to the preferred reporting items for systematic reviews and meta-Analyses statement.

Methods: The data of the prevalence of Nocardia species were collected from databases such as Embase, PubMed/MEDLINE via Ovid, Web of Science, Scopus and Google Scholar as well as national Iranian databases, including SID, Magiran. Analyses were conducted by STATA 14.0.

Results: The meta-analyses showed that the proportion of Nocardia spp. in Iranian studies varied from 1.71(1.17, 2.24) to 0.46(0.09, 0.83). N. asteroides (21% [95% CI 1.17, 2.24]), N. cyriacigeorgica (17% [95% CI 0.99, 1.77]), N. facanica (10% [95% CI 0.75, 1.00]) were considered to be common causative agents.

Conclusions: Our study presents that despite the fact that Nocardia spp. are normally are saprophytic organisms, are currently accounts as emerging pathogens due to an increase in immunocompromised patients among Iranian populations. Considering our results, the establishment of advanced diagnostic facilities for the rapid detection of Nocardia infections are required for optimal therapeutic strategies of Nocardia spp. in Iran. Our findings could help the programmatic management of the disease within the context of Nocardia control programs.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0254840PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8297923PMC
July 2021

Linezolid resistance among multidrug-resistant Mycobacterium tuberculosis clinical isolates in Iran.

Acta Microbiol Immunol Hung 2021 Jun 24. Epub 2021 Jun 24.

1Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

The management of multidrug-resistant (MDR) and extensively drug-resistant tuberculosis (XDR-TB) presents a main challenge and the drug options for treating these infections are very limited. Linezolid (LNZ) has recently been approved for the treatment of MDR and XDR-TB. But, there are narrow data on genotypic and phenotypic LNZ resistance in clinical isolates. So, we aimed to determine the prevalence of LNZ resistance and to identify the mutations associated with LNZ resistance among clinical MDR-TB isolates. The minimum inhibitory concentration (MIC) values of LNZ for 22 MDR-TB isolates were determined by broth microdilution method. All MDR-TB isolates were sequenced in the rrl and rplC genes conferring LNZ resistance. LNZ resistance was found in 3 (13.6%) of 22 MDR-TB isolates. The MICs of LNZ were 8 μg/mL for two isolates and 16 μg/mL for one isolate. The 421 (A/G) and 449 (T/A) mutations in rplC gene were detected in one of the LNZ-resistant isolates. There was no mutation in rrl gene. The results reveal that the prevalence of LNZ-resistant isolates is 13.6% among MDR-TB isolates and drug susceptibility testing (DST) against LNZ is useful in the management of complicated and drug-resistant cases. However, further studies could identify other possible genetic mechanism of resistance in TB.
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http://dx.doi.org/10.1556/030.2021.01490DOI Listing
June 2021

Molecular Identification, and Characterization of Strains Isolated from Four Tuberculosis Regional Reference Laboratories in Iran During 2016-2018.

Infect Drug Resist 2020 7;13:2171-2180. Epub 2020 Jul 7.

Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Background: Non-tuberculous mycobacterial (NTM) infections are growing concern in many countries around the globe including Iran. Among them, ( causes both pulmonary and extra-pulmonary infections. Despite the high prevalence of isolates in Iran, unfortunately little is known about the epidemiological aspects of infection. Hence, the aim of the present study was to investigate the molecular identification, determination of subtypes variation and geographic distribution of clinical isolates of isolates.

Methods: In the present study, 108 clinical pulmonary isolates suspected to NTM were collected from four Tuberculosis Regional Reference Laboratories in Iran during 2016-2018. The isolates were confirmed as NTM using conventional and molecular methods. Among them, isolates were subjected to gene sequencing. For determination of subtyping of isolates, polymerase chain reaction-restriction enzyme analysis (PCR-REA) based on the gene was performed.

Results: Based on the gene sequence analysis, 33 (30.5%) isolates were identified as species, compared to 31 (28.7%) isolates using phenotypic methods. The subtype I was the most frequent subtype (n=24; 72.7%), followed by subtype II (n=8; 24.2%).

Conclusion: We indicated that the rate of isolation with clinical significance appears to be increasing in Iran, especially in highly industrialized cities. The high rate of subtype I may suggest that this genotype has a particular potency for colonization, and a higher epidemiological potential for causing infection in humans. More studies are needed to provide a better understanding of the biology and pathogenicity of subtype I.
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http://dx.doi.org/10.2147/IDR.S245295DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7354002PMC
July 2020

Prevalence of Extended-Spectrum Beta-Lactamase-Producing Causing Bloodstream Infections in Cancer Patients from Southwest of Iran.

Infect Drug Resist 2020 6;13:1319-1326. Epub 2020 May 6.

Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Introduction: This study aimed to evaluate the frequency rate of extended-spectrum beta-lactamase-producing (ESBL-PE) causing bloodstream infections (BSIs) in cancer patients referred to one of the major referral hospitals in Ahvaz city, southwest Iran.

Materials And Methods: In this study, 1700 blood cultures were collected from 610 cancer patients suspected to have BSI from October 2016 to August 2017 referred to the Shafa cancer hospital, Ahvaz, southwest of Iran. The blood culture bottles were incubated aerobically at 35-37ºC for 24 hours and then sub-cultured on routine microbiology culture media. The bacterial colonies were identified using standard tests. The antibiotic susceptibility testing was achieved by the disc-diffusion method. The phenotypic detection of ESBLs was carried out by the combination disc-diffusion test (CDDT). Finally, the polymerase chain reaction (PCR) was performed to investigate the presence of , , and genes.

Results: The prevalence of BSI in cancer patients was 16.4% (100/610). Gram-negative rods with rate of 74% (74/100) were the most prevalent bacteria. The frequency of family was 21% including (n: 8), (n: 6), spp. (n: 5), (n: 1), and (n: 1). All isolates were multidrug-resistant (resistance to three or more antibiotics). The results of CDDT showed that 42.8% (9/21) of isolates had a positive ESBL test of which 100% (9/9) indicated positive band for at least one of the ESBL genes by PCR method. The and genes were detected in 38% (8/21) and 23.8% (5/21) of isolates, respectively, while the and were not detected in any isolates.

Conclusion: Based on the results, surveillance, and antibiotic stewardship programs should be implemented for cancer patients to prevent the spread of more ESBL-PE that have limited therapeutically choices.
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http://dx.doi.org/10.2147/IDR.S254357DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7212769PMC
May 2020

Investigation of SCCmec types I-IV in clinical isolates of methicillin-resistant coagulase-negative staphylococci in Ahvaz, Southwest Iran.

Biosci Rep 2020 05;40(5)

Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Today methicillin resistant coagulase-negative staphylococci (MR-CoNS) are important in terms of causing significant nosocomial infections. Besides, MR-CoNS are confirmed as the reservoir of SCCmec elements that carry mecA (methicillin-resistant) gene. Hence, the present study was designed to evaluate the susceptibility pattern, prevalence and diversity of SCCmec types I, II, III, and IV in MR-CoNS strains. In this cross-sectional study, 44 clinical isolates of MR-CoNS were identified using the cefoxitin disc method and further confirmation by polymerase chain reaction (PCR) amplification of the mecA gene. Antimicrobial susceptibility of isolates was investigated by disc diffusion. The identification of CoNS was done by amplification and sequencing of the tuf gene. Multiplex PCR method was done for the determination of SCCmec types. In the present study, the Staphylococcus epidermidis and Staphylococcus haemolyticus were the most predominant isolates with a prevalence of 45.4%. The highest resistance rates were observed against erythromycin (84.1%) and clindamycin (75%). Multiplex PCR revealed the SCCmec type I as the predominant type in the present study. Our study showed that there was no significant relationship between the presence of different types of SCCmec elements and resistance to antibiotics. The present study highlighted a frequent prevalence of MR-CoNS harboring SCCmec type genes in Ahvaz, southwest of Iran. Thus, the molecular typing and periodical monitoring of their drug resistance pattern should be considered in national stewardship programs to designing useful antibiotic prescription strategies.
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http://dx.doi.org/10.1042/BSR20200847DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7214399PMC
May 2020

Comparison Of And Efflux Pump Genes Expression In Drug-Susceptible And -Resistant Strains Isolated From Tuberculosis Patients In Iran.

Infect Drug Resist 2019 5;12:3437-3444. Epub 2019 Nov 5.

Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Background: Among different resistance mechanisms in (MTB), efflux pumps may have a role in drug-resistance property of MTB. So, the aim of this study was to compare the relative overexpression of two important efflux pump genes, and , among MTB isolates from TB patients.

Methods: A total of 37 clinical isolates of confirmed MTB isolates were analyzed. Drug susceptibility testing (DST) was performed using the conventional proportional method. Real-time semiquantitative PCR profiling of the efflux pump genes of and was performed for clinical isolates. The receiver operating curve (ROC) analysis for differentiation of resistant from susceptible isolates on the basis of efflux pump expression fold changes was also performed.

Results: According to DST, 16 rifampin (RIF) monoresistant, 3 isoniazid (INH) monoresistant, 5 multidrug-resistant (MDR) and 13 pan-susceptible isolates of MTB were evaluated for gene expression. The highest values of and gene expression fold changes were seen in MDR isolates, which were significant in comparison with susceptible isolates and H37Rv reference strain. By using comparative ROC analysis, the obtained cutoff point for and gene overexpression was the folds of >1.6 and >2.3, respectively.

Conclusion: The results of the present study confirm the role of DrrA-DrrB efflux pump in antibiotic resistance in clinical MTB isolates. As the large number of efflux pumps are located in the cell envelope of MTB, we cannot correlate a single efflux pump overexpression to the drug-resistance phenotype, unless all the pumps simultaneously investigated.
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http://dx.doi.org/10.2147/IDR.S221823DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6842285PMC
November 2019

Investigation of the prevalence of genes conferring resistance to carbapenems in isolates from burn patients.

Infect Drug Resist 2019 7;12:1153-1159. Epub 2019 May 7.

Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Currently, the rate of hospital-acquired infections due to drug-resistant strains shows an increasing trend and remains one of the principal reasons for mortalilty in burn patients. This study aimed to investigate the prevalence of genes conferring resistance to carbapenems in isolates from burn patients. A total of 50 isolates were tested for antibiotic susceptibility and presence of multidrug-resistant (MDR) and extensively drug resistant (XDR) isolates, using phenotypic tests. Screening for genes conferring resistance to carbapenems was investigated by multiplex PCR method. Susceptibility testing demonstrated the highest resistance against amikacin, ceftazidime (n=44/88% each), and gentamicin (84%), while colistin sulfate was the most effective antibiotic. The rate of MDR and XDR isolates was revealed as 50% and 40% respectively. We detected the following carbapenemase genes: (32%), followed by (18%), and (14%). This study revealed a high antibiotic resistance in isolates with a total of 40% and 50% MDR and XDR isolates respectively, and 70% carbapenem resistance. The prevalence of carbapenem conferring genes tested among carbapenem-resistant isolates was demonstrated as 65.7%. Due to the prevalence of strains carrying and genes in our hospital, more attention and implementation of effective control measures against nosocomial infection are recommended.
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http://dx.doi.org/10.2147/IDR.S197752DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6511252PMC
May 2019

Isolation and characterization of from environmental and clinical sources by culture and PCR-RFLP methods.

Iran J Microbiol 2019 Feb;11(1):7-12

Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Background And Objectives: Due to the widespread distribution of in environmental and animal sources and serious clinical complications in human, this study was aimed to isolate from water and clinical specimens by culture and PCR methods and to investigate the presence of and virulence genes.

Materials And Methods: Water and clinical samples of vaginal and fecal were screened for the presence of by phenotypic and standard biochemical tests. PCR amplification was performed on extracted DNA using primers based on the and genes. A 733-bp fragment of gene was used for investigation of polymorphism using RFLP analysis.

Results: In total, 45 phenotypically and molecularly confirmed strains were isolated from different sources including 30 (16.7%) from water, 9 (11.3%) from vaginal swabs and 6 (7.5%) from fecal samples. RFLP analysis of PCR products using and restriction enzymes, generated two profiles with 8 to 10 bands ranging in size from 15 to 210 bp. The majority of water and clinical isolates were classified in profile 2.

Conclusion: We demonstrated 45 isolates from tested water and clinical samples by phenotypic and molecular tests. The majority of the isolates were classified in the same RFLP profile, showing the water as a potential source of clinical complications in patients in the region of study.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6462272PMC
February 2019

Characterization of the most common gene mutations associated with ethambutol resistance in isolates from Iran.

Infect Drug Resist 2019 6;12:579-584. Epub 2019 Mar 6.

Khuzestan Tuberculosis Regional Reference Laboratory, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Introduction: Ethambutol (Emb) is one of the first-line drugs in the standard combination therapy for tuberculosis; however, due to the rapid increase in Emb resistance among clinical isolates of (MTB), early detection of Emb resistance is desirable. As the operon is considered involved in resistance to Emb, this study aimed to analyze the most common mutations within the operon among MTB isolates from Iran to find any correlations of these mutations with Emb resistance.

Methods: A total of 307 clinical isolates of MTB were screened for Emb resistance by phenotypic drug-susceptibility testing. PCR amplification was performed on extracted DNA from all Emb-resistant and randomly selected Emb-susceptible isolates using sets of primers for various gene loci of , , and , followed by sequencing for the detection of most common alterations.

Results: In total, ten isolates showed resistance to Emb by phenotypic susceptibility testing (3.25%). The mutation rate in ten Emb-resistant MTB strains was 20% (n=2), comprising one mutation in (10%), at codon 306 Met-Val and one in (10%) at codon 270 Thr-Ile. A nonsynonymous mutation in the gene in one of the randomly selected Emb-susceptible isolates located in codon 330 Leu-Leu was also noticed.

Conclusion: The majority of our Emb-resistant isolates (n=8, 80%) did not demonstrate the sequences investigated within the operon. As such, these mutations solely are insufficient for the development of complete resistance to Emb in MTB isolates. Additional mechanisms of resistance other than mutations in these sequences studied within the operon should also be considered.
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http://dx.doi.org/10.2147/IDR.S196800DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6411316PMC
March 2019

Prevalence of nontuberculous mycobacteria and high efficacy of d-cycloserine and its synergistic effect with clarithromycin against and .

Infect Drug Resist 2018 7;11:2521-2532. Epub 2018 Dec 7.

Tuberculosis Research Center, Hormozgan University of Medical Sciences, Bandar Abbas, Iran.

Background: The prevalence of pulmonary disease caused by nontuberculous mycobacteria (NTM) is reportedly on the rise in the world. Some of the species are resistant to various antibiotics; hence, limited treatment options are available. The aims of this study were to investigate the prevalence of NTM and to determine the effect of d-cycloserine against and isolated from clinical specimens to find out the synergistic effect of d-cycloserine and clarithromycin.

Methods: A total of 95 nonduplicate pulmonary isolates of NTM were collected from three major Regional Tuberculosis (TB) Centers. NTM isolates were identified by conventional tests and PCR sequence analysis of the gene. PCR sequencing of was performed for detecting the inducible resistance to macrolides. In vitro susceptibilities and activities of d-cycloserine-clarithromycin combinations were accessed using the broth microdilution method.

Results: Among 714-positive acid-fast bacilli from TB-suspected cases, 95 isolates were identified as NTM (13.3%). The prevalence of identified isolates was as follows: 46 (48.4%), 16 (16.8%), 15 (15.7%), 7 (7.3%), 4 (4.2%), 3 (3.2%), 2 (2.1%), and 2 (2.1%). In addition, sequence analysis could identify all NTM isolates. The effect of d-cycloserine was better than that of clarithromycin. The synergistic effect of d-cycloserine with clarithromycin was observed for six (100%) and five (71.5%) strains of and , respectively.

Conclusion: In the present study, we demonstrated a wide range of NTM in processed samples from different provinces of Iran. Our observations indicated that d-cycloserine was very active against and ; hence, d-cycloserine, either alone or in combination with clarithromycin, may be promising for the treatment of - and associated diseases.
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http://dx.doi.org/10.2147/IDR.S187554DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6290872PMC
December 2018

Molecular detection of rifampin, isoniazid, and ofloxacin resistance in Iranian isolates of by high-resolution melting analysis.

Infect Drug Resist 2018 18;11:1819-1829. Epub 2018 Oct 18.

Tehran Tuberculosis Regional Reference Laboratory, Tehran University of Medical Sciences, Tehran, Iran.

Background: The emergence of drug resistance among (MTB) strains is a serious health concern worldwide. The development of rapid molecular diagnostic methods in recent years has a significant impact on the early detection of resistance to major anti-TB drugs in MTB isolates, which helps in employing appropriate treatment regimen and prevents the spread of drug-resistant strains. This study was designed to evaluate the efficacy of real-time PCR and high-resolution melting (HRM) curve analysis for the determination of resistance to rifampin (RIF), isoniazid (INH), and ofloxacin (OFX) in MTB isolates and to investigate their resistance-related mutations.

Methods: HRM analysis was performed to screen 52 (32 drug-resistant and 20 fully susceptible) MTB clinical isolates for mutations in , , , and genes. The HRM results were then confirmed by DNA sequencing.

Results: In total, 32 phenotypically resistant isolates, comprising 18 RIF-, 16 INH-, and five OFX- resistant strains, were investigated. HRM analysis successfully identified 15 out of 18 mutations in , 14 out of 16 mutations in and , and four out of five mutations in conferring resistance to RIF, INH, and OFX, respectively. The obtained sensitivity and specificity, respectively, for HRM in comparison with phenotypic susceptibility testing were found to be 83.3% and 100% for RIF, 87.5% and 100% for INH, and 80% and 100% for OFX. In five resistant strains (12.8%), no mutation was detected by using HRM and DNA sequencing.

Conclusion: HRM assay is a rapid, accurate, and cost-effective method possessing high sensitivity and specificity for the determination of antibiotic resistance among MTB clinical isolates and screening of their associated mutations. This method can generate results in a shorter period of time than taken by the phenotypic susceptibility testing and also allows for timely treatment and prevention of the emergence of possible MDR strains.
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http://dx.doi.org/10.2147/IDR.S178831DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6202043PMC
October 2018

Application of gene sequence analysis for the identification of species of coagulase-negative staphylococci in clinical samples and evaluation of their antimicrobial resistance pattern.

Infect Drug Resist 2018 22;11:1275-1282. Epub 2018 Aug 22.

Department of Biostatistics and Epidemiology, School of Health, Kerman University of Medical Sciences, Kerman, Iran.

Introduction: Coagulase-negative staphylococci (CoNS) are normal inhabitants of human skin and mucous membranes. However, CoNS represent one of the major nosocomial pathogens, especially in immunocompromised patients. The increasing incidence of CoNS and mainly methicillin-resistant strains underlines the need for an accurate identification of Staphylococcus isolates at the species level. Analysis of the gene proved to be an accurate tool for the species identification of CoNS. The aims of this study were to identify the CoNS species by gene-based polymerase chain reaction method and sequencing, and to determine the frequency of CoNS clinical isolates resistant to methicillin (MRCoNS) and other antibiotics.

Methods: A total of 200 staphylococci isolates were collected from various clinical samples. Phenotyping methods were used for initial identification followed by polymerase chain reaction amplification of gene with subsequent sequencing. The phylogenetic relationships among species were analyzed using the neighbor-joining method based on the partial gene sequence of . Microbroth dilution test was used for screening methicillin resistance, and disk diffusion susceptibility testing was performed for evaluation of antibiotic resistance among the isolates.

Results: In the present study, 125 isolates were identified as CoNS; among them, 54(43.2%) and 50 (40.0%) were demonstrated as the most prevalent species. Resistance to methicillin was detected in 54.4% of the CoNS based on microbroth dilution method. In disk diffusion susceptibility testing, the greatest resistance of CoNS was demonstrated for cefoxitin (65.4%), cotrimethoxazole (54.4%), and clindamycin (49.6%), while daptomycin (87.2%) and linezolid (83.2%) showed the greatest effectiveness for CoNS isolates.

Conclusion: Our results confirmed the predominance of and among CoNS isolates. The high prevalence of MRCoNS strains is a serious concern and strongly suggests the need for control program measures in our hospitals in order to reduce MRCoNS infections, especially in immunocompromised patients.
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http://dx.doi.org/10.2147/IDR.S172144DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6112803PMC
August 2018

rpoB gene mutations among Mycobacterium tuberculosis isolates from extrapulmonary sites.

APMIS 2018 Mar;126(3):241-247

Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, USA.

The aim of this study was to analyze mutations occurring in the rpoB gene of Mycobacterium tuberculosis (MTB) isolates from clinical samples of extrapulmonary tuberculosis (EPTB). Seventy formalin-fixed, paraffin-embedded samples and fresh tissue samples from confirmed EPTB cases were analyzed. Nested PCR based on the rpoB gene was performed on the extracted DNAs, combined with cloning and subsequent sequencing. Sixty-seven (95.7%) samples were positive for nester PCR. Sequence analysis of the 81 bp region of the rpoB gene demonstrated mutations in 41 (61.2%) of 67 sequenced samples. Several point mutations including deletion mutations at codons 510, 512, 513 and 515, with 45% and 51% of the mutations in codons 512 and 513 respectively were seen, along with 26% replacement mutations at codons 509, 513, 514, 518, 520, 524 and 531. The most common alteration was Gln → His, at codon 513, presented in 30 (75.6%) isolates. This study demonstrated sequence alterations in codon 513 of the 81 bp region of the rpoB gene as the most common mutation occurred in 75.6% of molecularly confirmed rifampin-resistant strains. In addition, simultaneous mutation at codons 512 and 513 was demonstrated in 34.3% of the isolates.
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http://dx.doi.org/10.1111/apm.12804DOI Listing
March 2018

Distribution of genes encoding resistance to aminoglycoside modifying enzymes in methicillin-resistant Staphylococcus aureus (MRSA) strains.

Kaohsiung J Med Sci 2017 Dec 26;33(12):587-593. Epub 2017 Aug 26.

Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Electronic address:

Today Methicillin-Resistant Staphylococcus aureus (MRSA) have acquired multiple resistance to a wide range of antibiotics including aminoglycosides. So, this study was aimed to investigate the rate of aminoglycoside resistance and the frequency of aminoglycoside resistance mediated genes of aac(Ia)-2, aph(3)-IIIa and ant(4')-Ia among MRSA strains. A total of 467 staphylococci isolates were collected from various clinical samples. S. aureus strains were identified by standard culture and identification criteria and investigating of presence of 16S rRNA and nuc genes. Cefoxitin disk diffusion, and oxacillin-salt agar screening methods were used to detect the MRSA strains with subsequent molecular identification for the presence of mecA gene. Antibiotic susceptibility of MRSA strains against aminoglycoside antibiotics was evaluated by using agar disk diffusion method. Multiplex PCR for the presence of aac(Ia)-2, aph(3)-IIIa and ant(4')-Ia encoding genes for aminoglycosides were performed for MRSA strains. From total staphylococci tested isolates, 262 (56.1%) were identified as S. aureus, of which 161 (61.45%) were detected as MRSA and all comprised mecA gene. The resistance pattern of MRSA strains to aminoglycoside antibiotics were: gentamicin 136 (84.5%); amikacin 125 (77.6%); kanamycin 139 (86.3%); tobramycin 132 (82%); and neomycin 155 (96.3%). The frequency of aac(Ia)-2, aph(3)-IIIa, and ant(4')-Ia genes among MRSA strains, were 64%, 42% and 11.8% respectively. In conclusion, as MRSA strains are of great concern in human infections, the results of present study could provide a useful resource for health sectors for choosing appropriate antibiotics for the effective treatment of infections due to MRSA strains.
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http://dx.doi.org/10.1016/j.kjms.2017.08.001DOI Listing
December 2017

Genetic diversity of multidrug-resistant Mycobacterium tuberculosis strains isolated from tuberculosis patients in Iran using MIRU-VNTR technique.

Kaohsiung J Med Sci 2017 Nov 13;33(11):550-557. Epub 2017 Jul 13.

Department of Microbiology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.

Tuberculosis (TB) is considered as one of the most important infectious diseases in the world, and recent rise and spread of multidrug-resistant (MDR) Mycobacterium tuberculosis (MTB) strains, have made the matter worsened. Due to the importance of TB prevalence in Iran, this study was designed to investigate the genetic diversity among MDR strains of MTB by MIRU-VNTR typing scheme. A total of 88 drug resistant M. tuberculosis isolates belong to pulmonary TB cases were collected from several TB reference centers of Iran. Drug susceptibility testing for Isoniazid and Rifampin was performed using the agar proportion method and MDR isolates were underwent genotyping by using 12-locus- based MIRU-VNTR typing. On performing proportion method, 22 isolates were identified as MDR. By typing of MDR isolates using 12-loci MIRU-VNTR technique, high diversity were demonstrated in MDR strains and these were classified into 20 distinct MIRU-VNTR genotypes. MIRU loci 10 and 26 were the most discriminatory loci with 8 and 7 alleles respectively; while MIRU loci 2, 20, 24 and 39 were found to be the least discriminatory with 1-2 alleles each. We noticed a mixed infection in isolate 53, as this isolate comprised simultaneous two alleles in MIRU loci 40, 10, 16 and 39. In conclusion, this result represents MIRU-VNTR typing as a useful tool for studying genetic diversity of MDR-MTB in regional settings, and will help the health sectors to construct a preventive program for MDR-TB. Additionally, it can detect mixed infection which can facilitate management of treatment.
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http://dx.doi.org/10.1016/j.kjms.2017.06.011DOI Listing
November 2017

The frequency of class1 and 2 integrons in Pseudomonas aeruginosa strains isolated from burn patients in a burn center of Ahvaz, Iran.

PLoS One 2017 15;12(8):e0183061. Epub 2017 Aug 15.

Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Background: Pseudomonas aeruginosa is an opportunistic pathogen with the ability to cause severe nosocomial infections and remains a major problem in burn patients. This organism shows a remarkable antimicrobial resistance and is often resistant to multiple antibiotics. Integron genes as mobile genetic elements are playing an important role in the spread of P. aeruginosa antibiotic resistance. This study was aimed to investigate the occurrence of class 1, and 2 integron genes (int1, int2), among P. aeruginosa strains isolated from patients with burn infections.

Methods: In total 93 clinical isolates of P. aeruginosa were screened. The antimicrobial susceptibilities of 9 common antimicrobial agents were tested against the isolates using disk diffusion method. PCR amplification was performed on extracted DNAs for the detection of int1, and int2 genes using the set of specific primers.

Results: The majority of P. aeruginosa isolates were from wound infection (69.9%). In disk diffusion method, most isolates showed remarkable resistance to tested antibiotics with highest against gentamicin (94.62%) and ciprofloxacin (93.55%). PCR amplification revealed that 89(95.7%) of P. aeruginosa strains carried int1, but none of them harbored int2 genes. The distribution of int1 gene was highest in blood (100%), followed by wound isolates (95.38%).

Conclusions: We demonstrated a high antimicrobial resistance among P. aeruginosa isolates in our setting. int1 was prevalent and seems to play an important role in multidrug resistance among the isolates. So, performance of antibiotic surveillance programs is necessary for choosing the appropriate therapy and management of infection control practices.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0183061PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5557579PMC
October 2017

Frequency of rrs and rpsL mutations in streptomycin-resistant Mycobacterium tuberculosis isolates from Iranian patients.

J Glob Antimicrob Resist 2017 06 9;9:51-56. Epub 2017 Apr 9.

Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Objectives: Streptomycin (SM) is one of the most effective drugs for the treatment of multidrug-resistant (MDR) tuberculosis. However, resistance to SM is increasingly reported, mainly due to mutations in the rpsL and rrs genes. This study was designed with the aim of determining the nature of SM resistance and the type and frequency of rpsL and rrs mutations among SM-resistant Mycobacterium tuberculosis (MTB) isolates from Iran.

Methods: A total of 100 clinical monoresistant and MDR MTB isolates were subjected to drug susceptibility testing (DST) for SM. SM-resistant isolates were genotyped by MIRU-VNTR typing. Fragments of the rpsL and rrs genes were amplified to investigate the most common mutations, with subsequent sequence analysis.

Results: By DST, 32 isolates (32%) were identified as SM-resistant, of which 50% (16/32) were MDR. By MIRU-VNTR typing, the SM-resistant isolates were classified into 20 different MIRU types and 8 clusters, with Beijing (22%) being the most prevalent genotype. Mutations in the rrs and rpsL genes were identified in 14 (44%) and 10 (31%) of the 32 SM-resistant isolates, respectively. The most common mutations were at rpsL nucleotide 128 (AAG→AGG, Lys43Arg), found in 7 SM-resistant isolates (22%) and nucleotide 263 (A→G, Lys88Arg) in 3 SM-resistant isolates (9%).

Conclusions: The results suggest an association between rpsL mutation and SM-resistant strains of Beijing genotype. The existence of SM resistance in 25% of isolates without mutation in rrs and rpsL suggests the occurrence of further mechanisms associated with SM resistance in these isolates.
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http://dx.doi.org/10.1016/j.jgar.2017.01.005DOI Listing
June 2017

The frequency of genes encoding exotoxin A and exoenzyme S in Pseudomonas aeruginosa strains isolated from burn patients.

Burns 2016 Aug 2;42(5):1116-1120. Epub 2016 Jun 2.

Dept. of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Background: Pseudomonas aeruginosa infections have emerged as a major infectious disease threat in recent decades with infection particularly in immunocompromised hosts. P. aeruginosa possesses several virulence factors with involvement in pathogenesis. The aim of this study was to examine the prevalence of virulence genes of toxA and toxS and to analyze their relation to antimicrobial resistance of the isolates.

Methods: In total 185 clinical isolates of P. aeruginosa were collected from burn patients. Antimicrobial susceptibility testing was done by disk diffusion method. PCR amplification was performed on extracted DNA from the isolates and the presence of encoding genes for exotoxin A (toxA) and exoenzyme S (toxS) were investigated by using specific primers.

Results: In disk diffusion method, the isolates showed high sensitivity to colistin sulfate (100%) followed by imipenem (41.9%). The most prevalent resistance was seen against ceftazidime (90.5%) and gentamicin (88.5%). Multidrug resistance (MDR) demonstrated in 113 isolates (76.35%). According to PCR amplification, 133 (89.8%) and 127 (85.8%) isolates possessed toxA and toxS genes respectively. The frequencies of genes among MDR strains were 102 (76.6%) for toxA and 98 (77.1%) for toxS. Eighty five MDR isolates possessed both genes (73.9%). The non-MDR strains (23.65%), harbored lower prevalence of simultaneous toxA and toxS genes (26%) compared to MDR strains.

Conclusion: The present study established a higher frequency of MDR among P. aeruginosa isolates from burn patients. It was found that the frequency of both toxA &S genes were significantly higher in MDR strains P. aeruginosa strains.
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http://dx.doi.org/10.1016/j.burns.2016.02.012DOI Listing
August 2016

Prevalence of Non-Tuberculous Mycobacteria in Hospital Waters of Major Cities of Khuzestan Province, Iran.

Front Cell Infect Microbiol 2016 13;6:42. Epub 2016 Apr 13.

Department of Virology, School of Medicine, Ahvaz Jundishapur University of Medical Science Ahvaz, Iran.

Non-tuberculous mycobacteria (NTM) are among the emerging pathogens in immunocompromised individuals including hospitalized patients. So, it is important to consider hospitals water supplies as a source for infection. The aim of this study was to determine the prevalence of NTM in the hospital aquatic systems of Khuzestan, South west of Iran. In total, 258 hospital water samples were collected and examined. After initial sample processing, sediment of each sample were inoculated into two Lowenstein-Jensen medium. The positive cultures were studied with phenotypic tests including growth rate, colony morphology, and pigmentation, with subsequent PCR- restriction enzyme analysis (PRA) and rpoB gene sequence analysis. Mycobacterial strains were isolated from 77 samples (29.8%), comprising 52 (70.1%) rapid growing, and 25 (32.4%) slow growing mycobacteria. Based on the overall results, M. fortuitum (44.1%) was the most common mycobacterial species in hospital water samples, followed by M. gordonae (n = 13, 16.8%) and M. senegalense (n = 5, 7.7%). In conclusion, current study demonstrated the NTM strains as one of the major parts of hospital water supplies with probable potential source for nosocomial infections. This finding also help to shed light on to the dynamics of the distribution and diversity of NTM in the water system of hospitals in the region of study.
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http://dx.doi.org/10.3389/fcimb.2016.00042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4829604PMC
November 2016

Identification of clinical isolates of Acinetobacter baumannii from Iran and study of their heterogeneity.

J Chin Med Assoc 2016 Jul 4;79(7):382-6. Epub 2016 Apr 4.

Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Background: Acinetobacter baumannii has become one of the most serious causative agents of nosocomial infections due to its significant ability to survive on hospital surfaces. It is mainly an emerging opportunistic pathogen infecting patients in intensive care units. This study was aimed to identify the clinical isolates of A. baumannii and to investigate their heterogeneity using polymerase chain reaction (PCR)-based typing methods.

Methods: A total of 197 nonduplicate isolates recovered from a wide range of clinical samples were subjected to conventional cultural and biochemical tests. For those isolates that were preliminary identified as A. baumannii, rpoB-based PCR with subsequent restriction fragment length polymorphism (RFLP) using two restriction enzymes (TagI and HaeIII) was performed to investigate the genetic diversity of the strains and their presumptive relationships with different clinical presentation of the disease caused by this pathogen.

Results: In total, 50 isolates (25.4%) were identified as A. baumannii using conventional phenotypic methods with subsequent confirmation by rpoB sequencing. RFLP analysis demonstrated five different restriction enzyme patterns, designated as A-E clusters. Most A. baumannii isolates were categorized under Cluster A (32%). We found no significant relationship between clinical presentation and the clustering of the isolates.

Conclusion: This study showed that the rpoB region possesses high discriminatory power to identify the isolates to the species level. This marker showed high interspecies variability that might be useful for strain typing. The results also suggest the possibility of the existence of a predominant clone of A. baumannii among infected patients in Iran.
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http://dx.doi.org/10.1016/j.jcma.2016.01.012DOI Listing
July 2016

Genotyping of multidrug-resistant strains of Pseudomonas aeruginosa isolated from burn and wound infections by ERIC-PCR.

Acta Cir Bras 2016 Mar;31(3):206-11

Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Purpose: To determine the genetic diversity of MDR P. aeruginosa strains isolated from burn and wound infections in Ahvaz, Iran, by ERIC-PCR.

Methods: From total 99 strains of P. aeruginosa defined as MDR by using drug susceptibility testing, 66 were subjected to ERIC-PCR analysis, comprises 53 strains isolated from burn infection, and 13 randomly selected strains from wound infection with higher resistance to combinations of more numbers of drugs.

Results: Eight clusters (I to VIII), and 50 single clones were generated for tested MDR isolates analyzed by ERIC-PCR. The high heterogeneity was observed among the isolates from burn infections including 16 isolates which were categorized in eight clusters and 37 single clones. The isolates in clusters II, III, VI, VIII showed 100% similarity.

Conclusions: The high level of genotypic heterogeneity in P. aeruginosa strains demonstrated no genetic correlation between them. Extremely high drug resistance in isolates from burn, suggests that efficient control measures and proper antibiotic policy should be observed.
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http://dx.doi.org/10.1590/S0102-865020160030000009DOI Listing
March 2016

Prevalence of Escherichia coli O157:H7 in Children with Bloody Diarrhea Referring to Abuzar Teaching Hospital, Ahvaz, Iran.

J Clin Diagn Res 2016 Jan 1;10(1):DC13-5. Epub 2016 Jan 1.

Professor, Department of Pediatric, School of Medicine, Ahvaz Jundishapour University of Medical Sciences , Ahvaz, Iran .

Introduction: Escherichia coli O157: H7 are recognized as important aetiological agents of diarrhea in children, particularly in developed countries.

Aim: The aim of the study was to determine the rates of detection of E. coli O157: H7strains among children in Ahvaz, Iran.

Materials And Methods: From June 2010 to December 2010, 137 diarrheal stool samples of children were collected. E.coli was identified by standard microbiological techniques. O157 or O157:H7 subtypes discerned by serological tests.

Results: Of the 137 E. coli isolates, enteropathogens were found in 53 (38.7%) of the patients as follow: Shigella spp. (75.5%), EPEC (enteropathogenic E. coli) (16.9%), Campylobacter spp. (3.8%) and Salmonella spp. (3.8%). None of the isolated E. coli was O157:H7 serotype.

Conclusion: This shows that non-O157:H7 E. coli are the major cause of paediatric infections in this region of Iran.
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http://dx.doi.org/10.7860/JCDR/2016/16689.7134DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4740593PMC
January 2016

Molecular Identification of Clinical Isolates of Mycobacterium fortuitum by Random Amplified Polymorphic DNA (RAPD) Polymerase Chain Reaction and ERIC PCR.

J Clin Diagn Res 2015 Dec 1;9(12):DC01-5. Epub 2015 Dec 1.

Assistant Professor, Department of Immunology, Islamic Azad University , Jahrom Branch, Iran .

Backgrounds: Non tuberculous mycobacteria (NTM) are of importance now-a-days due to their increasing virulence outbreaks and emerging antibiotic resistance. Since the most common NTM in Iran is reportedly Mycobacterium fortuitum, the present study was designed with the aim of molecular identification of clinical isolates of M. foruitum to analyse their heterogeneity.

Materials And Methods: A total of 81 isolates of NTM isolated from various samples were collected. The clinical isolates were assigned to species M. fortuitum by using conventional and molecular methods. The DNA banding patterns of ERIC- PCR and RAPD- PCR were analysed by using Bionumeric 7.5 software.

Results: Out of 81 tested NTM, 36 strains of M. fortuitum were identified. 33 isolates were selected for molecular typing in this study. Based on RAPD and ERIC analysis, M. fortuitum isolates were divided into 3 and 6 clusters, respectively. Most of the isolates were distributed into types of II RAPD (20 members/ 60.6 %) and V (14 members/ 42.4% with sub cluster I & II) of ERIC. In RAPD analysis, the major fragments were 300 bp, followed by fragment 1000. In ERIC analysis, the major fragments were 280 bp followed by fragment 1200 bp.

Conclusion: In conclusion, though the results from this study represented higher discriminatory power of ERIC, however the combination of RAPD and ERIC analysis were able to sufficiently discriminate the genotypic diversity, infection control, and gain useful epidemiological information regarding M. fortuitum isolates.
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http://dx.doi.org/10.7860/JCDR/2015/15504.6909DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4717685PMC
December 2015

Molecular Methods for Identification of Acinetobacter Species by Partial Sequencing of the rpoB and 16S rRNA Genes.

J Clin Diagn Res 2015 Jul 1;9(7):DC09-13. Epub 2015 Jul 1.

Research Assistant, Department of Microbiology Unit, Masoud Medical Laboratory , Tehran, Iran .

Background: Acinetobacter spp. is a diverse group of Gram-negative bacteria which are ubiquitous in soil and water, and an important cause of nosocomial infections. The purpose of this study was to identify a collection of Acinetobacter spp. clinical isolates accurately and to investigate their antibiotic susceptibility patterns.

Materials And Methods: A total of 197 non-duplicate clinical isolates of Acinetobacter spp. isolates identified using conventional biochemical tests. The molecular technique of PCR-RFLP and sequence analysis of rpoB and 16S rRNA genes was applied for species identification. Antimicrobial susceptibility test was performed with a disk diffusion assay.

Results: Based on 16S rRNA and rpoB genes analysis separately, most of clinical isolates can be identified with high bootstrap values. However, the identity of the isolate 555T was uncertain due to high similarity of A. grimontii and A. junii. Identification by concatenation of 16S rRNA and rpoB confirmed the identity of clinical isolates of Acenitobacer to species level confidently. Accordingly, the isolate 555T assigned as A. grimontii due to 100% similarity to A. grimontii. Moreover, this isolate showed 98.64% to A. junii. Besides, the identity of the isolates 218T and 364T was confirmed as Genomic species 3 and A. calcoaceticus respectively. So, the majority of Acinetobacter spp. isolates, were identified as: A. baumannii (131 isolates, 66%), A. calcoaceticus (9 isolates, 4.5%), and A. genomosp 16 (8 isolates, 4%). The rest of identified species showed the lower frequencies. In susceptibility test, 105 isolates (53%), presented high antibiotic resistance of 90% to ceftriaxone, piperacillin, piperacillin tazobactam, amikacin, and 81% to ciprofloxacin.

Conclusion: Sequence analysis of the 16S rRNA and rpoB spacer simultaneously was able to do identification of Acinetobacter spp. to species level. A.baumannii was identified as the most prevalent species with high antibiotic resistance. Other species showed lower frequencies ranged from 4 to 9 strains.
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http://dx.doi.org/10.7860/JCDR/2015/13867.6188DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4572958PMC
July 2015

Application of Deletion- Targeted Multiplex PCR technique for detection of Mycobacterium tuberculosis Beijing strains in samples from tuberculosis patients.

Iran J Microbiol 2014 Oct;6(5):330-4

Department of Statistics, Mathematical Science and Computer Faculty, Shahid Chamran University, Ahvaz, Iran.

Background And Objective: Molecular epidemiological studies have shown that certain genotypes of Mycobacterium tuberculosis (MTB) are over-represented in limited geographical regions, suggesting of evolution of certain genotypes with increasing virulence and pathogenicity. Beijing strain of MTB was initially described by its potential to cause outbreaks worldwide and its association with drug resistance. Due to tuberculosis (TB)-related mortality which is associated with Beijing genotype, this study was designed with the aim to detect the MTB Beijing genotype in the region of study.

Materials And Methods: A total of 170 clinical isolates of MTB were collected from the TB reference laboratory of Khuzestan province, Iran, over one year period from February 2010 to February 2011. Phenotypic tests were used for preliminary detection of MTB. Culture positive MTB isolates were confirmed by multiplex PCR based on IS6110 gene with subsequent screening for resistance to isoniazid (INH), and rifampin (RIF) by PCR using relevant primers. Three set of primers were used to differentiate Beijing from non-Beijing strains by using Deletion- Targeted Multiplex (DTM) PCR.

Results: From 160 PCR-confirmed MTB isolates, 18 (11.25%) showed mutation in katG gene related to INH resistance and 20 (12.5%), associated with mutation in rpoB gene related to RIF resistance, and 8 (5%) were detected as Beijing strain using multiplex PCR. The majority of detected Beijing strains (6/8[75%]) comprised mutation in katG gene with the prevalent mutation specifically in codon 315. In 4 Beijing strains (2.5%), mutation in rpoB gene were also detected.

Conclusion: Using DTM- PCR, the rate of Beijing strains in the region of study was determined as 5%. Although for detection of MTB antimicrobial resistance, it is advised to use a combination of conventional antimicrobial susceptibility testing and molecular techniques, however for time saving, it seems that DTM-PCR, is a simple technique for use in areas of the world where Beijing strains are highly prevalent.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4385573PMC
October 2014

"Multidrug-resistant tuberculosis" may be nontuberculous mycobacteria.

Eur J Intern Med 2015 May 14;26(4):279-84. Epub 2015 Mar 14.

Division of Pulmonary and Critical Care, University of Illinois at Chicago, Chicago, IL, USA. Electronic address:

Introduction: Multidrug resistant tuberculosis (MDR-TB) presents a great challenge to public health, especially for developing countries. Some nontuberculous mycobacteria (NTM) cause the similar clinical and radiological characteristics with tuberculosis. We aimed to identify the frequency of NTM infections among subjects who were suspected to have MDR-TB due to lack of response to anti-TB treatment.

Methods: This retrospective study evaluated patients with suspected MDR-TB due to lack of sputum conversion after 2-3 month therapy with first line anti-TB treatment from 2009 through 2014. Cultures for mycobacteria were performed and identification was done to species level by phenotypic and molecular tests. The outcome of the patients with NTM disease and related risk factors for poor outcome were evaluated.

Results: Out of 117 consecutive strains isolated from suspected MDR-TB subjects, 35 (30%) strains were identified as NTM by using conventional and molecular approaches. Of these patients with positive NTM cultures, 32 (27%) patients met ATS/IDSA diagnostic criteria. Out of 32, 29 (90%) individuals with confirmed NTM diseases had underlying disorders including 8 subjects with malignancy, 5 with organ transplantations, and 4 with the human immunodeficiency virus. No known underlying disorder was found in 3 (9%) subjects. Treatment outcomes were available for 27 subjects, 17 (63%) of whom were cured and 10 (37%) had poor outcome including 6 (60%) who failed and 4 (40%) who died during treatment.

Conclusion: The high costs to the patient and society should lead health care providers to consider NTM in all patients suspected of having TB.
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http://dx.doi.org/10.1016/j.ejim.2015.03.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4414892PMC
May 2015

Nocardia co-infection in patients with pulmonary tuberculosis.

Jundishapur J Microbiol 2014 Dec 1;7(12):e12495. Epub 2014 Dec 1.

Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran.

Background: Tuberculosis (TB) remains as one of the most serious infectious diseases in the world. Pulmonary tuberculosis can occur with other pulmonary diseases caused by opportunistic organisms such as Nocardia spp. particularly in immunocompromised patients. Therefore, diagnosis of co-infection at the early stage of the disease could be lifesaving.

Objectives: The goal of this study was to detect Mycobacterium tuberculosis and Nocardia spp. in sputum specimens in order to assess the concomitant nocardiosis and tuberculosis in patients with suspected pulmonary tuberculosis.

Patients And Methods: From March 2011 to April 2012, 189 sputum specimens were obtained from patients who were suspected of having pulmonary tuberculosis. Out of 189 samples, 32 of the samples belonged to hospitalized HIV-infected patients. Samples were examined by Gram and Ziehl-Nelsen staining, culture and PCR methods.

Results: From 157 sputum specimens, positive samples by acid fast staining, culture and PCR for M. tuberculosis were reported for 7.6% (12/157), 10.1% (16/157) and 7% (11/157) of samples, respectively. No results were obtained by the described methods for Nocardia spp. Among 32 samples of HIV-infected patients, four (12.5%) had positive results for acid fast staining, culture and PCR detecting M. tuberculosis while only two samples had positive results for Nocardia spp. by PCR and no results were reported by culture, Gram and acid fast staining for this organism.

Conclusions: Concurrent pulmonary nocardiosis and tuberculosis is frequent in HIV-infected patients. Rapid and sensitive methods such as PCR are recommended for detection of such co-infections.
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http://dx.doi.org/10.5812/jjm.12495DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4335542PMC
December 2014

Bacterial urinary tract infection in renal transplant recipients and their antibiotic resistance pattern: A four-year study.

Iran J Microbiol 2014 Apr;6(2):74-8

Medicinal Plants Research Center, Yasuj University of Medical Sciences, Yasuj, Iran ; Health Research Institute, Infectious and Tropical Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Background And Objective: Urinary tract infections (UTIs) are the most common infections in renal transplant recipients and are considered a potential cause of bacteremia, sepsis, and affects graft outcomes. The aim of the present study was to determine the incidence of UTI among renal transplant recipients and investigation of antimicrobial susceptibility pattern of causative agents.

Materials And Methods: In total, 1165 patients from March 2009 to December 2012, in transplant center of Golestan Hospital, Ahvaz, Iran, were investigated. Qualitative urine cultures were performed for all cases, causative microorganisms were identified and colony count was performed according to the standard protocol. Antibiotic susceptibility testing was then performed to determine the susceptibility pattern of recovered bacteria from confirmed UTIs.

Results: UTI was diagnosed in 391 patients(33.56%). Gram-negative bacteria were the most prevalent isolated microorganisms with E. coli (43.53%), followed by Enterobacter spp. (35.37%) as the major organisms. Among Gram positives, Coagulase-negative Staphylococci was isolated from 6.8% of cases. The rate of resistance to all tested antibiotics was highest in Enterobacter spp., however the most common resistance were seen against cefixime, cephalotin, and cotrimoxazole in all tested gram negatives.

Conclusion: the rate of UTIs among renal transplant recipients was noticeable in this study with high antibiotic resistance. Multi-resistant bacterial infections are potentially life-threatening emerging problem in renal transplantation. Prophylactic measures must be applied to patients at greater risk.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4281663PMC
April 2014

Identification of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from burn patients by multiplex PCR.

Burns 2015 May 23;41(3):590-4. Epub 2014 Oct 23.

Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS) as important human pathogens are causes of nosocomial infections worldwide. Burn patients are at a higher risk of local and systemic infections with these microorganisms.

Objective: A screening method for MRSA by using a multiplex polymerase chain reaction (PCR) targeting the 16S ribosomal RNA (rRNA), mecA, and nuc genes was developed. The aim of the present study was to investigate the potential of this PCR assay for the detection of MRSA strains in samples from burn patients.

Methods: During an 11-month period, 230 isolates (53.11%) of Staphylococcus spp. were collected from burn patients. The isolates were identified as S. aureus by using standard culture and biochemical tests. DNA was extracted from bacterial colonies and multiplex PCR was used to detect MRSA and MRCoNS strains.

Results: Of the staphylococci isolates, 149 (64.9%) were identified as S. aureus and 81 (35.21%) were described as CoNS. Among the latter, 51 (62.97%) were reported to be MRCoNS. From the total S. aureus isolates, 132 (88.6%) were detected as MRSA and 17 (11.4%) were methicillin-susceptible S. aureus (MSSA). The presence of the mecA gene in all isolates was confirmed by using multiplex PCR as a gold standard method.

Conclusion: This study presented a high MRSA rate in the region under investigation. The 16S rRNA-mecA-nuc multiplex PCR is a good tool for the rapid characterization of MRSA strains. This paper emphasizes the need for preventive measures and choosing effective antimicrobials against MRSA and MRCoNS infections in the burn units.
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http://dx.doi.org/10.1016/j.burns.2014.08.018DOI Listing
May 2015
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