Investigation of blactx-m beta-lactamase resistance genes in extended spectrum beta-lactamase producing grams negative enterobacteria

Introductıon and Aim: In recent years, the most frequently encountered causative agent of community and nosocomial infections is the extended spectrum beta lactamase (ESBL) producing bacteria belonging to the Enterobacteriaceae family. The resistance to the beta lactam has been progressively increasing. It is important to detect the beta-lactam resistance in the Enterobacteriaceae family because of the difficulties faced in the provision of therapy. For his reason, we decided to investigate the most frequently isolated resistance gene (blaCTX-M) bearing type of the ESBL-producing bacteria, which has caused recent pandemics, in order to contribute to the regional epidemiological database. Materials and Methods: Clinical isolates included in this study were from the Clinical Microbiology Laboratory of the Medical School of the Recep Tayyip Erdogan University Hospital, which receives routine specimens from polyclinics, wards and ICU cases. The 276 tests included in this study were clinical isolates collected between 27 October 2010 and 28 February 2012, which were single samples from each patient and were defined as ESBL in accordance with the screening results. The ESBL diagnosis was confirmed by the combined disc diffusion method and the double disc synergy test, and the antibiotic susceptibility tests were carried out in line with the criteria of CLSI ( Clinical And Laboratory Standards for Antimicrobial Susceptibility Testing) . The beta lactamase resistance blaCTX-M genes were amplified by multiplex PCR employing two different sets of primers. Results: Of the 276 clinical isolates included in the study, 206 ( 74,6 %) were E. coli and 61 ( 22,2 %) were Klebsiella spp. The ward and polyclinic distribution of the isolates was found to be the same. 194 ( 70,2 %) of the isolates were found to contain blaCTX-M beta lactamase resistance genes. While the most frequent CTX-M group was CTX-M-1 ( 79,8 % ), there was none of the CTX-M-8 type. In the antibiotic sensitivity tests, > 90 % resistance to third generation cephalosporins was detected. Resistance to ciprofloxacin (from Quinolones) and trimetoprim/sulfamethoxazole was found to be over 50%. No carbapenem-resistant isolate was found. Discussion and Conclusion: In Turkey and in the world, the increase in the ESBL production in general and that of CTX-M resistance of plasmid origin in particular, and the dramatic increase in the resistance to the beta lactam antibiotics have necessitated some preventative actions. Accurate determination of the genotype and phenotype of ESBL, the requirement of the issueing of new policies on the use of antibiotics, and the conduction of epidemiological studies fort he constitution of databases is inescapable. In conclusion, more studies and continuous training in this subject are impotant requirements. Key Words: Extended Spectrum Beta lactamase, CTX-M Enzymes, Enterobacteriaceae