Antibiotic-Resistance Patterns and Prevalence of CTX-M25 Type Extended-Spectrum β-lactamases in Escherichia coli and Klebsiella pneumonia In Patients with Leukemia

Background and Objectives: Bacterial infections are the most common cause of morbidity and mortality in patients with leukemia after undergoing intensive chemotherapy. Extended-spectrum beta-lactamase of CTX-M25 type is considered as an important mechanism resistant to cephalosporin in the gram-negative patogene and is wildly growing. Enterobacteriaceae species are able to produce extended-spectrum beta-lactamases (ESBLs). The aim of this study was to investigate the prevalence of CTX-M25 genes in isolated Escherichia coli and Klebsiella pneumoniae in patients with leukemia in Shariati hospitals. Materials and Methods: This study was carried out on the 80 E. coli and Klebsiella pneumoniae strains isolated. Then, the susceptibility of isolates to 8 selected antibiotics was tested using disc diffusion method. Later, the ESBL producer strains were confirmed using combined discs method. Finally, the blaCTX-M25 gene was determined using PCR . Results: Of the 80 isolates, 63 % and 58% showed resistance to Cefotaxime and Ceftriaxone respectively, 51(63%) isolates were ESBL producers. PCR showed that 0(0%) of isolates contained CTX-M25 gene . Conclusion: Resistance to various beta-lactam antibiotics, in particular, the cephalosporins is a serious concern.