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In this study, we aimed to identify the genetic lineages of Mycobacterium tuberculosis isolates in Isfahan via the mycobacterial interspersed repetitive-unit-variable number tandem repeat typing method based on 15 loci. Forty-nine M. tuberculosis isolates were collected between 2013 and 2015 from Tuberculosis patients in Mollahadi Sabzevari Tuberculosis Center in Isfahan. All isolates were typed by 15-locus MIRU-VNTR typing. The highest percentage of isolates, 44.89 % (22/49), belonged to the Euro-American lineage, while the frequencies of the East-African-Indian, East-Asian, and Indo-Oceanic lineages were 28.57 % (14/49), 24.4 % (12/49), and 2.04 % (1/49), respectively. Among the 22 isolates of the Euro-American lineage, those belonging to the NEW-1 sub-lineage were most prevalent (24.4 %). Approximately, the same proportion of isolates belonging to the Delhi/CAS, Beijing, and NEW-1 sub-lineages were identified in Iranian and Afghan immigrant patients. The Delhi/CAS and Beijing sub-lineage isolates were prevalent among patients who had been previously treated for TB. Results showed that all of the 49 MIRU-VNTR patterns were unique and the clustering rate of the 15-locus MIRU-VNTR was 0.0 (minimum recent transmission). The results of this study show that the lineages of M. tuberculosis isolates in Isfahan are similar to those reported in the Eastern Mediterranean region (indicative of the epidemiological relationship between the countries in the region). The low clustering rate in our results reveals that transmission of tuberculosis in Isfahan is, in most cases, a reactivation of previous tuberculosis infection and the role of recently transmitted disease is minor.

doi:10.3906/sag-1305-6

Background: We are witnessing the increasing use of antibiotics and the upward trend of resistant nosocomial infections. Therefore, identifying pathogens and determining the local patterns of antibiotic resistance are the health system's priorities in any region. Objectives: The current study aimed to investigate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the Intensive Care Unit (ICU) and Non-ICU wards, the toxic shock syndrome toxin-1 (TSST-1), alpha-toxin (Hla), and pantone-valentine leucocidin (PVL) genes in S. aureus strains, and antibiotic resistance patterns to provide a clinical guide for clinicians in Southwest Iran. Methods: Staphylococcus aureus was isolated from clinical specimens between 2018 and 2020. Methicillin-resistant S. aureus was detected by cefoxitin screening. Then, the antimicrobial resistance of all isolates was tested with the disk diffusion (DD) and the minimum inhibitory concentration (MIC) methods. Virulence genes, including TSST-1, Hla, and PVL, were evaluated by the PCR method. Results: Of 186 S. aureus strains isolated from various specimens, 51 (27.4%) were MRSA, with a 26.8% rate in the ICU. All isolates were susceptible to vancomycin, teicoplanin, linezolid, daptomycin, and quinupristin-dalfopristin. The penicillin-resistant S. aureus proportion was 93.5% (174/186), and more than 50% of all S. aureus isolates were resistant to fluoroquinolones. The incidence rates of virulence factors, including TSST-1, Hla, and PVL genes in MRSA, were 3.9%, 39.2%, and 2%, respectively. Conclusions: It is recommended to start empiric treatment against MRSA in case of severe infections in the ICU with either quinupristin-dalfopristin, daptomycin, vancomycin, teicoplanin, or linezolid until the culture and antibiotic susceptibility test results are available. Nevertheless, following the antibiotic resistance pattern is necessary to start treatment for other infections.

Background:Nontuberculous mycobacteria (NTM) are a group of opportunistic pathogens and these are widely dispersed in water and soil resources. Identification of mycobacteria isolates by conventional methods including biochemical tests, growth rates, colony pigmentation, and presence of acid-fast bacilli is widely used, but these methods are time-consuming, labor-intensive, and may sometimes remain inconclusive.Materials and Methods:The DNA was extracted from NTM cultures using CTAB, Chelex, Chelex + Nonidet P-40, FTA® Elute card, and boiling The quantity and quality of the DNA extracted via these methods were determined using UV-photometer at 260 and 280 nm, and polymerase chain reaction (PCR) amplification of the heat-shock protein 65 gene with serially diluted DNA samples.Results:The CTAB method showed more positive results at 1:10–1:100,000 at which the DNA amount was substantial. With the Chelex method of DNA extraction, PCR amplification was detected at 1:10 and 1:1000 dilutions.Conclusions:According to the electrophoresis results, the CTAB and Chelex DNA extraction methods were more successful in comparison with the others as regard producing suitable concentrations of DNA with the minimum use of PCR inhibitor.

Drug-resistant tuberculosis is considered a major universal problem. Based on knowledge on certain mutations occurring in Mycobacterium tuberculosis genome, drug resistance could be detected timely. The goal of this study was to determine the prevalence of the most common mutations likely to result from resistance to streptomycin in M. tuberculosis isolates, as well as genetic patterns of rpsL and rrs genes, in the province of Isfahan, Iran.Clinical specimens were collected from individuals suspected of tuberculosis who referred to the Tuberculosis Center of Isfahan among whom 205 isolates were diagnosed with M. tuberculosis by conventional methods. The minimum inhibitory concentration of streptomycin in these isolates was determined with proportion method using Lowenstein-Jensen medium from which 10 isolates were recognized with streptomycin-resistant tuberculosis. The nucleotide sequence of rpsL and 530 loop of rrs genes were analyzed in all streptomycin-resistant isolates, in addition to five randomly selected streptomycin-susceptible isolates.Six (6/10‚ 60%) streptomycin-resistant isolates represented a mutation in either rpsL gene and/or rrs530 loop. Four (40%) isolates showed rpsL mutations (codons 43 and 88), and two (20%) of them alterations in rrs gene (A514C and C517T). However‚ no mutation was found in streptomycin-susceptible isolates in either of the genes.The study could successfully highlight the positive effects of rpsL and rrs mutations as molecular markers of streptomycin resistance in M. tuberculosis strains. Diversity and presence or absence of mutations suggested possible circulation of a variety of strains and the role of additional mechanisms contributing to strstreptomycin resistance in various regions.

Background and Objectives: Today, because of the spread of drug resistance and the prevalence of infectious diseases, the use of medicinal plants has increased. So, in this study, the antibacterial effect of hydroalcoholic extract of Oak jaft and Echium amoenum was investigated on Shigella flexneri. Methods: In this study, hydroalcoholic extracts were extracted by maceration method and concentrated by rotary evaporator then dried immediately. Next, the antimicrobial effect of different dilutions of extracts on Shigella flexneri was investigated by disk diffusion and micro broth dilution methods and compared with two antibiotics, ciprofloxacin and trimethoprim-sulfamethoxazole. Results: The results showed that in proportion to the increase in the concentration of oak jaft extract, its antibacterial effect on Shigella flexneri also increased and 3.9 and 7.8 mg/ml of the extract were obtained by MIC and MBC dilution micro broth method, respectively. In the case of Echium amoenum extract, bacteria were grown at all dilutions (except the main stock of the extract (250 mg/ml)) and the extract had no antimicrobial effect on Shigella flexneri. Conclusion: According to the results of this study, oak jaft extract had a good inhibitory effect on Shigella flexneri and in comparison, with ciprofloxacin antibiotic, a similar inhibitory effect was observed and in comparison, with trimethoprim sulfamethoxazole, more inhibitory effect was observed.

Background: Due to the increase in microbial resistance, nosocomial multidrug resistance infections, including ventilator-associated pneumonia (VAP), are presently one of the main causes of death in hospitals since they are difficult to treat. Objectives: This study aimed to investigate the bacterial etiology of VAP and their microbial resistance pattern in Dezful Hospital, southwest of Iran. Methods: In this cross-sectional study, 131 bacterial isolates were isolated from the respiratory secretions of the patients with VAP in ICU wards. Antibiotic susceptibility testing (AST) of all isolates was carried out after the identification. Then the extended-spectrum beta-lactamases (ESBLs), carbapenemase, and metallobetalactamase were identified by phenotyping and genotyping. Results: The most frequent isolates were Staphylococcus aureus (30.5%), Acinetobacter baumannii (25.2%), and Klebsiella pneumoniae (24.4%). All strains of S. aureus were sensitive to vancomycin, ticoplanin, quinupristin-dalfopristin, and linezolid. Escherichia coli and Klebsiella showed high resistance to cephalosporins. More than 93% of Acinetobacter isolates were resistant to carbapenem and quinolones. The overall prevalence of ESBLs and carbapenemase producing bacteria were 80.43% and 73.6%, respectively. The most frequent ESBLs gene was blaCTX-M gene (78.3%) followed by blaAMP-C gene (67.5%), blaSHV gene (64.8%), and blaTEM gene (54%). Conclusions: In sum, there was a possibility that the treatment of nosocomial multidrug resistant infections such as VAP would become a major challenge. Therefore, it was recommended that AST results should always be considered when selecting the appropriate treatment regimen. Furthermore, it was found important to emphasize the principles of antibiotic stewardship and to constantly monitor the pattern of microbial susceptibility.