Infections in Iran

Currently some parasitic and viral infections, tuberculosis, brucellosis and hospital-acquired infections are challenging issues in Iran. Despite decreasing the rate of some infectious diseases in Iran in recent years, improved sanitation, active surveillance, comprehensive infection control strategies and monitoring appropriate use of antibiotics are indispensable. © 2018 The Autho

A frequency and molecular typing study of methicillin-resistant staphylococcus aureus isolates in teaching hospitals in Shahrekord, southwestern Iran

Methicillin-resistant Staphylococcus aureus (MRSA) remains a significant public health problem and treatment challenge. Objectives: This study was conducted to determine the frequency, molecular types, and drug resistance of S. aureus isolated from nasal carriers in two teaching hospitals (Hajar and Kashani) in Shahrekord, southwestern Iran. Methods: In this cross-sectional study, 262 nasal specimens were obtained from healthcare staff. The disk-diffusion method was used to detect MRSA. Nine antibiotic disks were used to determine the antibiotic susceptibility pattern. Staphylococcal cassette chromosome mec (SCCmec) types were identified by the multiplex polymerase chain reaction (PCR). The data analysis was performed using Fisher’s exact test with SPSS software. Results: Forty-eight (18.8%) specimens were identified as S. aureus, of which 30 (11.45%) specimens were methicillin resistant. The nasal colonization rate of the MRSA isolates was not associated with age or gender (P > 0.05). The highest resistance (33%) recorded was to rifampin, and all the isolates were susceptible to quinupristin-dalfopristin, vancomycin, and linezolid. The SCCmec results showed that 16.7%, 6.7%, 20%, and 56.6% of MRSA isolates were types I, II, III, and IV, respectively. Conclusions: Nasal isolates of MRSA were prevalent among hospital staff. The highest level of resistance was to rifampin, and all the isolates were susceptible to quinupristin-dalfopristin, vancomycin, and linezolid. SCCmec type 4 was the most frequent MRSA isolate. © 2016, Ahvaz Jundishapur University of Medical Sciences

Molecular epidemiology and nitrofurantoin resistance determinants of nitrofurantoin-non-susceptible Escherichia coli isolated from urinary tract infections

Objectives: The worldwide emergence of multidrug-resistant uropathogens has resulted in the revival of old antibiotics such as nitrofurantoin (NIT) for the treatment of uncomplicated urinary tract infections (UTIs). This study aimed to identify determinants of NIT resistance and to investigate the genetic diversity of NIT-resistant (NIT-R) Escherichia coli isolates. Methods: Six NIT-R and three NIT-susceptible clinical E. coli isolates from patients with UTI were studied. The susceptibility of the isolates to various classes of antibiotics was evaluated by disk diffusion. The presence of plasmid-encoded efflux pump genes (oqxA and oqxB) was investigated by PCR. Nucleotide sequences of the nfsA, nfsB and ribE genes were determined. The genetic relatedness of the NIT-R isolates was evaluated by multilocus sequence typing (MLST). Results: All six NIT-R isolates were characterised with high-level NIT resistance (MIC � 512 mg/L) and they belonged to five distinct STs including ST131 (n = 2), ST73, ST405, ST10 and ST354 (n = 1 each). Amikacin, carbapenems, minocycline, tigecycline and fosfomycin were the most active agents against the studied uropathogens. The oqxA and oqxB genes were not detected in any isolate. All NIT-R isolates harboured inactivating genetic alterations in nfsA and nfsB NfsA H11Y, S33N, S38Y, W212R substitutions, �g638 (frameshift), �a64-g73 (frameshift) and NfsB F84S, P45S, W94Stop, E197Stop substitutions, �nfsB locus. The ribE gene of most isolates was unaffected, except for one isolate co-harbouring a deleterious RibE G85C substitution and NfsA/B alterations. Conclusion: NIT resistance in the studied E. coli isolates was mainly mediated by nfsA and nfsB alterations. © 201

Development of a new DNA extraction protocol for PFGE typing of Mycobacterium tuberculosis complex.

A modified pulsed-field gel electrophoresis (PFGE) protocol was developed and applied to clinical isolates of Mycobacterium tuberculosis complex to reduce the cost of using lyticase. This protocol reduces the expense of PFGE typing of Mycobacterium tuberculosis complex as it removes the use of lyticase during the spheroplast formation from these bacteri

Microbiological qualification of air, water and dialysate in a haemodialysis centre; a new focus on Legionella spp.

Background and Objectives: The microbiological monitoring of the water used for haemodialysis is important especially for Legionella and non-fermentative bacteria since patients with end stage renal disease (ESRD) are suffering from deteriorated function of immune system. Materials and Methods: A total 50 water and dialysate samples were weekly collected over a period of 10 weeks from 5 sites. Total and faecal coliforms were determined by utilizing the most probable number (MPN) method. For isolation of Legionella, water samples were inoculated on a BCYE medium. DNA extraction was performed and was used to amplify 16S rRNA gene of Legionella species. Airborne bacteria were sampled using a single stage Andersen air sampler. Results: Out of total 50 water samples, 24 samples had bacterial contamination. The highest rate of Legionella contamination was observed in the storage tank (67 cfu/ml). Legionella was not isolated from the dialysate effluent samples. The highest rate of total bacterial count was related to the dialysate effluent and the maximum total count of coliforms was related to the reverse osmosis. The isolated bacteria were Gram-negative bacilli (mostly Pseudomonas isolates), Gram-positive cocci (mostly Micrococcus spp.) and Gram-positive bacilli (mostly Bacillus spp.). Six samples were contaminated with coliforms. No faecal coliform was isolated from the samples. Conclusion: These results indicated that dialysis machine is an important source of contaminations such as Staphylococcus, Pseudomonas and Legionella. Therefore an efficient prevention program is needed to eliminate bacterial contamination of dialysis water system. Moreover, in haemodialysis centres, periodic surveillance programs for microbiological qualification can lead to a better planning for disinfection of haemodialysis water systems. © 2016, Tehran University of Medical Science. All rights reserved

Methicillin-Resistant Staphylococcus epidermidis in Iran: A Systematic Review and Meta-Analysis

Objective: Methicillin-resistant Staphylococcus epidermidis (MRSE) remains one of the most prevalent drug-resistant bacteria causing health care infections. Limited data are available about how the frequency of MRSE changed in Iran over the past years. The current study aimed at determining the frequency of MRSE in different cities of Iran. Methods: Databases including Web of Sciences, Scopus, Embase, Medline, and Iranian databases were searched to find studies addressing the frequency of MRSE in Iran published from Mar 2006 to Jan 2016. The data were analyzed using comprehensive meta-analysis version 2.2 (Biostat). Of the 139 records identified in the databases, 15 studies met the inclusion criteria. Results: The analyses showed that the frequency of MRSE infections was 73.9% [95% confidence interval (95% CI) 61.4 - 83.4] among culture-positive cases of S. epidermidis in different parts of Iran. The frequency of MRSE was higher in the studies conducted from 2011 to 2015, based on further stratified analyses. Conclusions: The regular surveillance on antimicrobial susceptibility pattern and formulation of definite antibiotic policy may control high rate of MRSE associated infections in Iran. Moreover, rapid and reliable diagnosis of MRSE isolates and regular screening of the personnel and surfaces of hospitals in terms of MRSE are indispensable

Rapid Detection of Rifampicin- and Isoniazid-Resistant Mycobacterium tuberculosis using TaqMan Allelic Discrimination

Objectives: Multidrug-resistant tuberculosis (MDR-TB) is a global problem that many countries are challenged with. Rapid and accurate detection of MDR-TB is critical for appropriate treatment and controlling of TB. The aim of the present study was to evaluate the TaqMan allelic discrimination without minor groove binder (MGB) as a rapid, efficient, and low-cost method for detection of drug resistant strains of Mycobacterium tuberculosis. Methods: A total of 112 M. tuberculosis isolates from cases with diagnosed TB were subjected to drug susceptibility testing (DST), using the proportion method. Resistant isolates were tested for characterization of mutations in the rpoB and KatG genes by TaqMan genotyping. Results: Of 112 M. tuberculosis isolates for which DST was performed, three, one, and two isolates were MDR, rifampin (RIF) resistant, and isoniazid (INH) resistant, respectively. According to the threshold cycle (Ct) and curve pattern of mutants, TaqMan probes detect all of the mutations in the analyzed genes (katG 315, AGC�ACC, rpoB 531, TCG�TTG, and rpoB 531, TCG�TGG). Conclusion: The present study suggests that drug-resistant strains of M. tuberculosis can be detected by pattern's curve or Ct with TaqMan probes without MGB in real-time polymerase chain reaction (PCR). © 2016

Mutation in mgrB is the major colistin resistance mechanism in Klebsiella pneumoniae clinical isolates in Tehran, Iran

Colistin is considered as one of a last resort antimicrobial agent against multidrug-resistant Gramnegative bacteria including Escherichia coli and Klebsiella pneumoniae. However, the recent emergence of colistin resistance (ColR) worldwide that severely restricts therapeutic options is a serious threat to global public health. In this study we have investigated the molecular determinants in ColR K. pneumoniae isolates collected from clinical specimens. A total of 98 E. coli and 195 K. pneumoniae clinical isolates were collected from two hospitals from August 2018 to December 2019 in Tehran, Iran. Colistin susceptibility and minimum inhibitory concentrations (MIC) were determined according to the Clinical and Laboratory Standards Institute by disk diffusion method, and microdilution method, respectively. For isolates with colistin MIC >= 4 mu g mL(-1), PCR was performed for the detection of mcr-1 to mcr-4 genes. Moreover, nucleotide sequences of mgrB, phoP, phoQ, pmrA, and pmrB genes were determined by sequencing. Finally, the transcriptional level of pmrK and pmrC genes was evaluated by quantitative reverse transcription PCR (RT-qPCR). None of the E. coli isolates were resistant to colistin while 21 out 195 K. pneumoniae isolates were identified as resistant, 19 of which carried mutation in the mgrB gene. Three different mutations were observed in the pmrB gene in 3 K. pneumoniae isolates. None of the ColR isolates showed alternations in pmrA, phoP, and phoQ genes. Furthermore, none of the plasmid-encoding genes were detected. Transcriptional level of the pmrK gene increased in all ColR isolates meanwhile, pmrC overexpression was detected in 16 out 21 (76.19%) isolates. Eventually, all ColR isolates were susceptible to tigecycline. Our results demonstrated that the alternation of mgrB gene is the main mechanism related to colistin resistance among ColR K. pneumoniae isolates in this study