The molecular identification of resistance of gram negative bacteria, which are mostly isolated from hospital infecitons, against beta lactam antibiotics, aminoglycosides and colistin.

The increase in colistin resistance in addition to the development of co-resistance to carbapenems and aminoglycosides in Gram-negative bacteria, which are the causative agents of nosocomial infections, is worrying. In this study we aimed to determine the relationship between the resistance against beta lactam antibiotics, aminoglycosides and colistin and the resistance genes in Gram negative bacteria which are mostly isolated from nosocomials Isolated from Adana Sehir Hospital as a nosocomial infection agent of 101 K. pneumoniae, 93 E. coli, 61 P. aeruginosa and 85 A. baumannii, totally 340 strains which are isolated from various policlinics, services and intensive care units, probable beta lactamase genes, plasmid-mediated methyltransferase genes responsible for aminoglycoside resistance and mcr-1 gene which is responsible for colistin resistance are investigated with PCR and verified with sequence typing method. The probable relationship in type of the resistant strains is investigated with Pulse Field Gel Electrophoresis (PFGE) phylogenetically. In addition the high resistance against to carbapenems and aminoglycoside, the resistance against to colistin was recorded as 18.2 %. The rate of strains which are resistant strains against both carbapenem and aminoglycoside together was 53.5%; the rate of resistant strains against both aminoglycoside and colistin together was 14.4%. While the blaCTX-M-1, the highly determined resistance gene, blaOXA-48 like, which is most often determined resistance gene for carbapenease and rmtH, which is mostly isolated resistance gene for methyltranferases were found. Plasmid-mediated mcr-1 gene is isolated from only one E. coli strain. It was observed that resistance genes affected the antibiotic resistance risks statistically significantly. It was determined that blaCTXM-9, blaOXA-48 like and blaOXA-51 like genes increased the resistance risk in colistin-resistant isolates and isolates that developed resistance against carbapenem and colistin together. blaCTXM-9, blaOXA-48 like, blaOXA-51 like and rmtH genes were found to increase the resistance risk in isolates that developed resistance together against carbapenem, aminoglycoside and colistin, and in isolates that developed resistance against aminoglycoside and colistin together. According to PFGE analysis results, resistance profiles of closely related strains were different from each other. We think that early detection of these resistance genes, which can be carried together on the same plasmids in Gram-negative bacteria isolates, and knowing their relationship with the risk of developing resistance to antibiotics will contribute to the development of rational antibiotic use policies. In addition, our study is the first in our country to identify the plasmid-mediated mcr-1 gene responsible for colistin resistance in human clinical E. coli isolates.