Distribution of Antimicrobial Resistant Genes in Acinetobacter calcoaceticus-baumannii Complex Isolated from Clinical Specimens in Chungcheong, Korea

충청지역의 임상검체로부터 분리된 Acinetobacter calcoaceticus-baumannii Complex를 대상으로 항균제 내성 유전자 비교분석 성지연 극동대학교 임상병리학과 Species that belong to the Acinetobacter calcoaceticus-baumannii (Acb) complex are major causes of hospital-acquired infections.They are important opportunistic pathogens.These species are usually multidrug resistant (MDR), and the therapeutic options to treat the infections caused by these species are limited.In the present study, we investigated fluoroquinolone resistance mechanisms in 53 ciprofloxacin resistant Acinetobacter species isolates in Chungcheong, Korea.Antimicrobial susceptibilities were determined using the disk-diffusion method.Detections of genes and identification of mutations associated with fluoroquinolone resistance were carried out using PCR and DNA sequencing.In our study, 47 out of 53 ciprofloxacin resistant Acinetobacter isolates harbored sense mutations at the 83rd residue (serine to leucine) in the gyrA gene as well as at the 80th residue (serine to leucine) in the parC gene.Among the 47 isolates harboring sense mutations in gyrA and parC gene, 44 isolates were A. baumannii and 3 isolates were A. pittii.Plasmid-mediated quinolone resistance (PMQR) determinants were detected in isolates in our study.Among the 46 ciprofloxacin resistant A. baumannii isolates, 41 showed type A, B, or F banding patterns on their REP-PCR profiles.This result suggests that clonal relation and horizontal spreading of the bacterial isolates have been around hospitals in Chungcheong area.To prevent colonization and disseminations of fluoroquinolone resistance Acb complex isolates, continuous investigation and monitoring of antimicrobial resistant determinants of MDR isolates are needed.