Determination of associated antimicrobial resistance in Klebsiella spp, Escherichia coli, and Enterobacter spp clinical isolates at a public hospital in Goiania city, Brazil.

Abstract

The determination in the level of associated resistance in bacterial pathogens
to several classes of drugs has great importance in therapeutic protocols. A
retrospective analysis of the in vitro susceptibility for a range of antimicrobials was
carried out to quantify the associated resistance to one antimicrobial in the presence
and absence of resistance to each of the other ones. Escherichia coli (n = 515),
Klebsiella spp (n = 653) and Enterobacter spp (n = 507) isolates, from January
2006 to December 2008, were used. Among ESBL-producing Klebsiella spp and
E. coli isolates (54.7% - 357/653 and 15.3% - 79/515, respectively), significant
rates of associated resistance to the unrelated antimicrobials: aminoglycosides,
ciprofloxacin and trimethoprim-sulfamethoxazole were observed. The resistance in
Enterobacter spp to cefepime was associated with a marked increase in resistance
to all other agents tested (superior to 80 %), including quinolones, aminoglycosides
and sulfamethoxazole-trimethoprim, with exception to ampicillin-sulbactam
(58.7%). These results clearly indicate that associated resistance is not limited to
particular drug combinations, but is a general event that demonstrate the necessity
of greater caution regarding empirical therapy, because it's a relevant clinical
problem regarding the therapeutic options that are affected by the presence of
associated resistance to unrelated drugs.