Antibiotic Resistance and Genotypes of Nosocomial Strains of Acinetobacter baumannii in Kazakhstan

The aim of this study was to determine the prevalence of A. baumannii antibiotic-resistant strains in Kazakhstan and to characterize genotypes related to epidemic "high-risk" clones. Two hundred and twenty four A. baumannii isolates from four cities of Kazakhstan in 2011-2019 were studied. Antibiotic susceptibility testing was performed by using broth microdilutions method according to EUCAST (v 11.0) recommendations. The presence of bla(OXA-23-like), bla(OXA-24/40-like,) bla(OXA-58-like,) bla(VIM,) bla(IMP,) and bla(NDM) genes was determined by PCR. Genotyping was performed using high-throughput real-time PCR detection of 21 SNPs at 10 chromosomal loci used in existing MLST schemes. Resistance rates to imipenem, meropenem, amikacin, gentamicin, and ciprofloxacin were 81.3%, 78.6%, 79.9%, 65.2%, and 89.3%, respectively. No colistin resistant isolates were detected. The values of the MIC 50% and the MIC 90% of tigecycline were 0.125 mg/L, only four isolates (1.8%) had the ECOFF value >0.5 mg/L. The presence of acquired carbapenemase genes was found in 82.2% strains, including bla(OXA-23-like) (78.6%) or bla(OXA-58-like) (3.6%) genes. The spreading of carbapenem resistant A. baumannii strains in Kazakhstan was associated with epidemic "high-risk" clonal groups, predominantly, CG208(92)(OXF)/CG2(PAS) (80.8%) and less often CG231(109)(OXF)/CG1(PAS) (1.8%).