Molecular characterization resistance in MDR (Multi drug resistance) acinetobacter strains isolated from invasive infections, comparison of the relationship between strains with karakterizasyonu, suşlar arası klonal ilişkinin PFGE (Pulse field gel elektrophoresis) and MLST (Multi locus sequencing typing )

There are major difficulties in the treatment and prevention of acinetobacter infections, which are among the factors of HCAI (Healthcare associated Infections) that cause high mortality and morbidity as well as loss of labor force, psychological and economic burden. Acinetobacter infections frequently encountered in intensive care units with epidemic outbreaks of MDR and are thought to be spreading with drug resistant strains in all current publications. The most important strategy to prevent the spread of increasing resistance in recent years is the establishment of surveillance systems. The aim of this study is to investigate the molecular characterization of the resistance mechanisms of MDR or Pan-drug A.baumannii isolates and community-acquired strains isolated from polyclinic patient samples, to determine clonal relationships between strains, to compare international isolates and to investigate the spread of resistance in hospital and community. In this study, we evaluated A.baumannii strain isolated from samples collected from patients receiving treatment from different clinical services, intensive care units and outpatient clinics for 18 months from two separate tertiary hospitals in two major cities in the Mediterranean region where population movement was intense. After identification of the isolates by automated systems in both centers, we confirmed them with conventional methods and with blaOXA-51 gene positivity in our center. As 3 of the 160 isolates from two centers were negative for blaOXA-51, we conducted the study with 157 isolates. We evaluated the clonal relationships between isolates by PFGE method and used MLST method for comparisons with international isolates. As a result of PCR-based studies to determine the molecular mechanisms of antibiotic resistance, we detected that from the 157 isolates, 139 (88.5%) were blaOXA-23, 76 (48.4 % )were blaOXA-235, 19 (12.1 %) were blaOXA-24 positive. While in 74 (47.1 %)of them blaOXA-23 and blaOXA-235 were both positive, we found that from 19 blaOXA-24 positive isolates, 1 was both blaOXA-24 and blaOXA-235, 7 were both blaOXA-23 and blaOXA-24 positive and in 8 of them were containing this 3 genes together. Also we found that previously unworked blaOXA-23 gene in our country, was the highest detected carbepenamase gene after blaOXA-23. In addition, we found 56 (35.7%) of the isolates were positive for TEM gene. Also, adeC gene was detected in all isolates, while adeB, adeR, adeA, adeS genes were 96.8 %, 95.5 %, 90.4 % and 74.5 % respectively. When aminoglycoside resistance examined, armA methylase gene was detected at the highest rate (68.2 %), while the highest ratio of AME genes (49 %) was found to have aph (3)1. We found that the pmrA gene associated with colistin resistance was 95.5% positive. As a result of PFGE analysis of 157 isolates, 79 different pulsotypes were detected, 149 isolates were clustered in 14 different PFGE groups (A-Y) with 85 % similarity level, while 8 isolates were totally unrelated. C group (n = 43), G group (n =27), D group (n = 21) were the main groups, especially in the C group we observed that the intensive care isolates were clustered. The clonal relationship detected in 94.9 % of the isolates suggested that the distribution of A.baumannii isolates did not produce major differences. In our study, as a result of MLST analysis of 41 randomly selected isolates, we found that 2 isolates belong to ST718, 1 isolate belongs to ST158 sequence type, while the remaining 38 isolates have ST-2 sequence type which is known to be the most common sequence type in Europe. We think that this study will shade light on the strategies to be developed for the treatment and the prevention of A. baumannii infections in Turkey.While the epidemic clones in our country are not known clearly, we concluded that the CC-2 clone, which is known to be the most common in Europe, is also the most common clone in our country.