Evaluation of thymol effect on antimicrobial susceptibility and biofilm production in clinical Enterobacter spp . producing ESBLs and KPC enzymes

ABSTRACTBackground Multidrug-resistant Enterobacter strains that harbour Klebsiella pneumoniae carbapenemase and Extended Spectrum β-Lactamases genes are a therapeutic challenge in hospitals that have made infection control and antibiotic therapy difficult and use of natural compounds such as thymol is interesting in the treatment of infections.Methods Sixty-seven Enterobacter spp. isolates were obtained from patients admitted to hospitals in Hamadan and Tehran. Antimicrobial susceptibility, ESBLs and KPC genes detection and biofilm production of isolates were measured.Findings The results showed that the highest and lowest antibiotic resistance were related to ceftazidime (82.1%) and tigecycline (3%), respectively. Also, 79.1% of the isolates were MDR. The highest presence of genes was related to TEM (100%), SHV (82%), CTX-M (77%) and KPC (8.96%) genes. The MIC and MBIC of thymol were obtained 8-31 μg/ml and16-62 μg/ml, respectively.Conclusion Use of thymol, as an aid in antibiotic therapy is recommended.KEYWORDS: Thymolantimicrobial susceptibilitybiofilm productionenterobacterbeta lactamase AcknowledgmentsThe authors are thankful to the Research and Technology of Hamadan University of Medical Sciences, Hamadan, Iran for their financial support.Disclosure statementNo potential conflict of interest was reported by the author(s).Authors’ contributionsR. Y and M. T designed the study. Sh. Kh, and M. T contributed to the experimental studies and drafted the work. Sh. Kh, and M. T contributed to the sample collections. All authors read and approved the final manuscript.Ethical approvalThis study was approved by the Ethics Committee of Hamadan University of Medical Sciences, Hamadan, Iran (Ethical approval No. IR.UMSHA.REC.1399.283).Additional informationFundingThis study was funded by Hamadan University of Medical Sciences, Hamadan, Iran (Grant No. 9910307582).