Distribución de genes codificadores de β-lactamasas de espectro extendido en aislamientos de Klebsiella pneumoniae de hospitales de Bogotá, D.C., Colombia

Introduction. Extended spectrum β-lactamases (ESBL) are the most widely distributed enzymes in Enterobacteriaceae of Latin America and are key enzymes in resistance to antibiotics in common use. However, in Colombia, little information is available concerning the identity of genes coding for these enzymes in Klebsiella pneumoniae. Objective. The bla genes were identified in K. pneumoniae isolated from hospitals in Bogota D.C., Colombia. Materials and methods. One hundred seventy-seven isolates of ESBL producers were collected from 10 hospitals in Bogota between 2003 and 2005. Antibiotic susceptibility was determined by disk diffusion, and the number of β-lactamases in each isolate was assessed by isoelectric focusing. blaCTX-M, blaSHV and blaTEM were identified by PCR and subsequent sequencing. Results. Besides, the resitenance to third generation cephalosporins, 44.7 % and 49.7 % were resistant to amikacyn and thrimetoprim-sulaphametoxazole respectively. Lower resistance rates to other antibiotics were observed as well. An average of three β-lactamases were detected by isoelectric focusing, and the genes blaCTX-M-12 (56.0%) and blaSHV-12 (33.3%) were the most prevalent. blaSHV-5 (11.8%), blaCTX-M-1 (4.0%), blaSHV-27 (2.8%), blaSHV-2 (2.8%), blaCTX-M-2 (1.7%) and blaCTX-M-15 (0.6%) were present in smaller percentages. In addition, three genes were identified that coded for narrow spectrum β-lactamases. Conclusion. Eleven bla genes were identified, eight of which were ESBL-coding. The diversity of the bla genes suggested a continuing exposure of K. pneumoniae to strong antibiotic pressures in Bogota hospitals.