Genotypic and Phenotypic characteristics different types of efflux pump in acinetobacterbaumannii isolated from patients in ICU in alzahra hospital, Isfahan, 1396

Background: In recent years, due to the extensive use of antibiotics, the emergence of multiple drug-resistant (MDR) strains has dramatically increased that lead to limited efficiency of many commonly used antibiotics. In the present study, we investigate the distribution and involvement of drug efflux system in conferring resistance to amikacin in MDR isolates of Acinetobacterbaumanniiobtained from hospitalized patients. Methods: This cross-sectional study was carried out between March 2017 and June 2017 among 80 MDR A. baumannii isolates obtained from hospitalized patients in Alzahra hospital, Isfahan, Iran.A. baumannii isolates were identified by standard microbiologic procedure and confirmed by specific PCR primers. Minimum inhibitory concentration (MIC) was determined by agar dilution method according to CLSI guidelines. The presence of effluxgenes was detected by PCR method. Results: Antibiotic susceptibility results showed 39 (48.8%) of isolates had a MIC ≥32µg/mL and were amikacin-resistant. Totally, 41 isolates which had an amikacin MIC ≥2 μg/mL were tested for reduction of MIC in the presence of 25 μg/mL efflux pumps inhibitor. After treatment inhibitor, 25 (61%) isolates had ≥2 fold and 15 (36.6%) isolates had 4 fold reduction toward MIC of amikacin. Of 80 MDR A. baumannii isolates, the presence of AdeA, AdeB, AdeC, AdeM and AdeS genes were 100%, 96.3%, 96.3%, 98.8%, and 95%, respectively. Conclusion: In summary, significant involvement of drug efflux system in conferring resistance to amikacin along with high distribution of efflux genes suggests an alternative therapy using antibiotics in combination with efflux inhibitors in the fight against MDR isolates.

کلیدواژه ها:

Acinetobacterbaumannii ، MDR ، Amikacin ، Efflux pumps ، AdeABC genes