Determination of colistin resistance in acinetobacter species and investigation of mcr resistance genes

Acinetobacter species, which are quite common in nature, are serious pathogens that can live in many environments and foods, are associated with the health system and cause epidemics. Acinetobacter spp. is one of the most important causes of hospital infections and causes concerns because it can persist in hospital environments for a long time and can quickly become resistant to antibiotics. The rapid spread of multidrug-resistant Acinetobacter spp. infections has brought the use of colistin into question. In current studies, increasing resistance rates against colistin in Acinetobacter spp. isolates are noteworthy. Colistin resistance can be transmitted via plasmid-borne colistin resistance (mcr) genes or chromosomally. In our study, we aimed to determine colistin resistance in Acinetobacter spp. isolates using liquid disk elution and broth microdilution methods and to detect mcr (1-5) resistance genes by PCR method. 49 Acinetobacter spp. strains isolated from various clinical samples taken from patients applying to Van YYU Dursun Odabaş Medical Center were included in the study. Identification of strains and their resistance to other antibiotics were determined by Phoenix M50 (Becton Dickinson, USA) automated system. For colistin resistance, the results were compared by working with Disk Elution and Broth Microdilution Methods. The presence of mcr (1-5) genes transferred by plasmid in 49 Acinetobacter spp. strains was investigated by PCR method. As a result, it was determined that Acinetobacter spp strains had high resistance rates to amikacin, gentamicin, levofloxacin, ciprofloxacin, trimethoprim-sulfamethoxazole, imipenem and meropenem. Colistin resistance was found to be 12.2% by the reference method broth microdilution. All strains were found to be susceptible by the liquid disk elution method. The liquid disk elution method failed to detect colistin resistance when compared to BMD. The mcr (1-5) resistance genes, which are transmitted via plasmid for colistin resistance, were not found in any of the 49 strains.