Microbiology
Shabnam khavandi; Mohsen Arzanlou; Roghayeh Teimourpour; Hadi Peeridogaheh
Abstract
Background & Objective: Carbapenem-resistant is Gram-negative bacteria representing a worldwide public health problem. The present study aims to survey the phenotypic and genotypic characteristics of carbapenem-resistant Escherichia coli isolates collected from hospitalized patients and outpatients ...
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Background & Objective: Carbapenem-resistant is Gram-negative bacteria representing a worldwide public health problem. The present study aims to survey the phenotypic and genotypic characteristics of carbapenem-resistant Escherichia coli isolates collected from hospitalized patients and outpatients in Ardabil province, Iran.Methods: Two hundred samples were collected from the patients who had already been referred to the hospitals in Ardabil, Iran, from January to June 2017. Each patient's social and demographic data were recorded in the first step. The resistance profile of all E. coli isolates against imipenem and meropenem antibiotics were determined using the Kirby-Bauer disk diffusion method. Moreover, the broth microdilution method determined the Minimum Inhibitory Concentration (MIC) of E. coli isolates to imipenem. The Carbapenem Inactivation Method (CIM) and Carba NP test were employed for screening carbapenem-resistant strains. The frequency of carbapenem-encoding genes was determined using Polymerase Chain Reaction (PCR) method. The Enterobacterial Repetitive Intergenic Consensus (ERIC)-PCR analysis was used to evaluate the genetic relatedness of E. coli isolates.Results: Out of 200 urine samples, 66% (n = 132) of the samples were collected from women. The patients' age varied from 1 month to 93 years. Results of the disk diffusion method revealed that 33% (n=66/200) of E. coli isolates were resistant to imipenem. However, imipenem resistance was detected in 37% (n = 74/200) of the E. coli isolates using broth microdilution method. All E. coli isolates were negative in CIM and Carba NP tests. Moreover, we could not detect any carbapenemase encoding genes among E. coli isolates. The ERIC-PCR method revealed the E. coli strains were classified into 39 clusters with 80% similarity.Conclusion: It appears that E. coli is the most common cause of urinary tract infection in Ardabil province.
Microbiology
Helia Ostad Asadolah-Malayeri; Mojdeh Hakemi-Vala; Kambiz Davari
Volume 11, Issue 4 , October 2016, , Pages 345-353
Abstract
Background: This study aimed to evaluate the role of efflux pump regulator and OXA-23 genes in imipenem resistance Acinetobacter baumannii strains isolated from hospitalized patients in Tehran, Iran. Methods: This study was conducted on 60 A. baumannii isolates collected from patients admitted to the ...
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Background: This study aimed to evaluate the role of efflux pump regulator and OXA-23 genes in imipenem resistance Acinetobacter baumannii strains isolated from hospitalized patients in Tehran, Iran. Methods: This study was conducted on 60 A. baumannii isolates collected from patients admitted to the Shahid Motahari and Taleghani Hospitals in Tehran during 2013-14. Antibiotic susceptibility tests (AST) and minimal inhibitory concentration (MIC) was determined by broth micro dilution methods according to CLSI 2014 guidelines. The frequency of efflux pump adeRS and OXA-23 genes were detected by PCR and further sequencing. Results: The resistance of A. baumannii isolates to tested antibiotics was 100% to cefotaxime, ceftazidime, ceftriaxone, ciprofloxacin, cefepime, piperacillin, meropenem, co-trimoxazole and piperacillin/tazobactam, 97% to imipenem, 94% to gentamicin, 83% to amikacin, 76% to tetracycline, and 0.0% to colistin. The MIC of 58 (96.6%) strains to imipenem was highly decreased in the presence of efflux pump inhibitor (PaβN), by 4 to 64 folds. The adeR and adeS genes were detected in 36 (60%) and 59 (98.3%), respectively and the frequency of OXA-23 gene was 57 (95%) of isolates. Conclusion: Existence of adeRS and OXA-23 genes in more than 50% of A. baumannii isolates in this study shows the presumptiverole of efflux pump in simultaneous of carbapenemase production. Therefore, using new strategies are required in order to stop the vertical or horizontal exchanges mentioned genes from the resistant A. baumannii isolates to sensitive strains.