Nadia M. Elsheshtawy*, Shimaa A. Abdel Salam
The extended- spectrum β-lactamase producing Gram Negative bacteria are widely spread worldwide. Productions of these enzymes cause bacterial resistance to beta-lactam antibiotics as penicillin and cephalosporins. These enzymes act by hydrolyzing these antibiotics. Many ESBL variants are known that have been classified into nine different structural and evolutionary families based upon alteration of the amino acid configuration around the enzyme active site such as TEM, SHV, CTX-M, PER, VEB, GES, BES, TLA, and OXA.
Aim: To determine the distribution of ESBL (blaTEM and blaCTX-M) genes among the Gram negative isolates collected from urine samples in Intensive care units of Ain Shams University Hospitals.
Materials and Methods: The study was conducted on 40 Gram negative isolates, isolated from urine samples from Intensive care units of Ain Shams University Hospitals from July 2018 till December 2018. All the isolates were subjected to conventional microbiological identification methods, Antimicrobial susceptibility testing by disc diffusion test, followed by Polymerase chain reaction for detection of blaTEM and blaCTX-M ESBL genes.
Results: In this study, Phenotypic detection of ESBL among the isolates showed that 8 (20%) isolates were ESBL producers by double disc method and 32 (80%) non ESBL producers. ESBL gene (blaTEM ) was found in 15 isolates (37.5%) and ESBL gene (blaCTX-M) was found in 8 isolates (20%) and five isolates were positive for both genes.
Conclusion: Traditional Phenotypic tests for ESBL production cannot detect the ESBL subtype and cannot detect those genes whose expression is masked. Therefore, the genotypic method is suggested as the method of choice for detection of ESBL-producing strains among gram negative bacteria. The distribution of blaTEM was (37.5%) and blaCTX-M was (20%) and five isolates were positive for both gene.
Published Date: 2021-03-09;