Resumen

GARCIA ROMERO, Ibonne Aydee et al. Molecular characterizacion of multi-cephalosporin resistan Enterobacter cloacae isolates from a third level hospital in Bogota-Colombia. rev.fac.med. [online]. 2005, vol.53, n.3, pp.148-159. ISSN 0120-0011.

Background. Enterobacter species were normal in gastrointestinal tract, but nowadays, its biology has changed and there are nosocomial agents with antibiotics resistance. Objective. To make an epidemiological and molecular characterization of 20 isolates of Enterobacter cloacae with third generation cephalosporin resistance, from a hospital of third level in Bogotá-Colombia. Material and methods. Isolates were identified with Microscan and VITEK, Enterobacter asbureae was utilized as an inter-specie control. Resistance was confirmed by agar diffusion and by BLEE techniques. Isoelectric points were determined by ultrasound lyses and genotypication by Versalovic´s system for gram negative bacteria. Results. The isolates collected over the course of a year caused 15 cases of intra-hospital infection and two colonisations. All isolates presented resistance to cefotaxime, ceftazidime, ceftriaxone, aztreonam and ciprofloxacin, 95% to amikacin, gentamicin and chloramphenicol, 75% to trimethoprim/ sulphamethoxazole, 20% to cefepime and all were sensitive to imipenem. Two isolates were confirmed as extended spectre â-Iactamase (ESBL) producers by microbiologic al combined disktechnique; two â-Iactamases having 5.4 and 8.2 isoelectric points (pI) were presented by isoelectric focusing. Between 2 and 4 â-Iactamases having 5.4, 6.0, 7.0, 8.2 and >8.2 pl were detected in the 18 isolates which were not inhibited by clavulanic acid. Third-generation cephalosporin-resistance was attributed to AmpC hyper-production; pl values suggested simultaneous SHV and TEM â lactamase production. Genotyping by three rep- PCR methodologies (ERIC, REP and BOX) grouped the population studied into 7clones; 6 were constitute d by a single isolate and the predominant E1/B1/R1 clone grouped 14 isolates causing infection in 10 patients. This work led to a multiresistant Enterobacter cloacae clone being detected, considered endemic for the institution, in the studied surgical patients it was una predominantly cause of intrahospital infection. Conclusion. We detected a clone of Enterobacter cloacae with multi-cephalosporin resistance, has an endemic strain in a hospital of third level in Bogotá, who caused nosocomial infection, in special of surgical patients.

Palabras clave : enterobacter cloacae; cephalosporins; beta-lactamases; ampholyte mixtures; clone cells; infection; cross infection.

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