comparison of beta-lactamase profiles and epidemiology of multi-drug resistant acinetobacter baumannii isolates in southwest turkey: 2011 vs. 2019 study

Background: the most significant problem encountered with hospital infections caused by multi-drug resistant acinetobacter baumanniiisolates is the difficulty in treatment. defining resistance mechanisms is important for the development of treatment strategies. objectives: the aim of this study was to investigate the beta-lactamase genes and clonal relationship in multi-drug resistant a. baumanniiisolates in mugla, turkey, as no data are currently available for this province. methods: total 96 multi-drug resistant a. baumanniiisolates obtained from hospitalized patients, between 2011 - 2012 period (n = 61) and in year 2019 (n = 35) were investigated and compared for antibiotic susceptibilities, beta-lactamase enzyme encoding genes by polymerase chain reaction (pcr) method. repetitive extragenic palindromic (rep) pcr was made for dendrogram analysis to illustrate hierarchical relationship between isolates. results: overall, 74.0% of the isolates were obtained from patients in intensive care units. all multi-drug resistant isolates were found resistant to ciprofloxacin, piperacillin, piperacillin-tazobactam, meropenem, and imipenem by the disk diffusion method. the minimum inhibitory concentration values indicated that all isolates were resistant to imipenem, while colistin resistance was determined as 21.9%. the is aba-iinsertion element was present in all isolates. blaoxa-23-likewas present in 96.9%, and blaoxa-24-likewas detected in three (3.1%) isolates. blandmpositivity was shown in 5.2% of isolates. the indistinguishable or closely related isolates ratio was detected as 29.5% for the 2011 - 2012 period and 80% for 2019. conclusions: our findings showed that antibiotic resistance rates were high in a. baumannii, particularly isolated from intensive care unit patients in mugla province. the prevalence of beta-lactamase and metallo-beta-lactamase genes has been increasing year by year, with the blaoxa-23-likegene region being the most prevalent. additionally, the co-existence of these genes among strains is also on the rise. these findings from two different periods may provide useful reference data for future studies.