Evaluation of antibiotic susceptibility, prevalence of extended-spectrum beta-lactamase (ESBL), antimicrobial resistance (MDR), and biofilm formation ability in clinically isolated Escherichia coli

BACKGROUND AND OBJECTIVESEscherichia coli (E. coli) is an opportunistic bacterium with high prevalence that has high antimicrobial resistance (AMR). Investigating the sensitivity pattern, biofilm formation ability and presence of colistin-resistant mcr-۱, ۲ genes in multi-drug resistant (MDR) E. coli bacteria is one of the main goals of this study. After biochemical and molecular confirmation tests, sensitivity test, biofilm formation and minimum inhibitory concentration to colistin were performed on ۱۰۰ E. coli isolates.MATERIALS AND METHODSSample collection and identification of ۱۰۰ bacterial isolates was done. Antibiotic susceptibility testing was performed based on disc diffusion method. ESBL phenotypes were detected through the results of the Antibiogram. Semi- quantitative biofilm formation assay was done. MIC for colistin antibiotic was measured using microtiter plate assay.Total DNA was extracted. Molecular detection of the target genes was performed. Statistical analysis was done.RESULTS AND DISCUSSIONDisc diffusion method showed that the highest sensitivity was against imipenem (۹۸%), amikacin (۹۶%) and gentamicin (۸۱%), respectively. Among the isolated E. coli, ۴۷ strains (۴۷%) were determined as extreme beta-lactamase (ESBL) phenotype that respectively, ۴۵%, ۶۴%, ۸۵% of them are able to forming weak, moderate and strong biofilm, and ۵۳% of they were unable to produce biofilms. ۷۲ (۷۲%) were determined as MDR, ۵۹ strains (۹۴.۸۱%) of MIC>۲ are resistant and ۱ strain (۱۰۰%) of MIC≤۲ are sensitive to colistin. mcr-۱ gene was found in ۲۶ (۳۶.۱۱%) colistin-resistant strains and ۱ (۱.۳۸%) colistin-sensitive isolate. ۳۷.۴۹% of MDR positives have mcr-۱ and no mcr-۲ gene was detected in the isolates. Half of the mcr-۱ are able to produce biofilm.CONCLUSIONA high level of resistance was observed in ampicillin, trimethoprim sulfamethoxanole and colistin which can be prevented with community awareness and appropriate health policies.

کلیدواژه ها:

Eshershia coli ، Antibiotic resistant ، Colistin