Occurrence and transferability of β-lactam resistance in Enterobacteriaceae isolated in Children's University Hospital in Bratislava

Occurrence and transferability of beta-lactam resistance in 30 multi-resistant Escherichia coli, Klebsiella spp., Enterobacter spp., Pantoea agglomerans, Citrobacter freundii and Serratia marcescens strains isolated from children between 0 and 3 years of age is presented. The strains were resistant to ampicillin (30), cefoxitin (22), cefotaxime (30), ceftriaxone (30), ceftazidime (30) and aztreonam (28), but susceptible to cefepime (30) and imipenem (26). Twenty-eight of 30 isolates possessed a transferable resistance confirmed by conjugation and isolation of 79-89-kb plasmids. The beta-lactam resistance was due to production of beta-lactamases and ceftazidime proved to be stronger beta-lactamase inductor than ceftriaxone. Twenty-five clinical isolates expressed transferable extended spectrum beta-lactamases, and chromosomally encoded AmpC beta-lactamase.