Occurrence of extended-spectrum beta-lactamases in Enterobacteriaceae isolated from hospitalized patients in Curitiba, southern Brazil.
Production of extended-spectrum beta-lactamases (ESBL) by enterobacteria is an important resistance mechanism against antimicrobial beta-lactamics. We tested 498 bacterial strains isolated from two tertiary-care teaching hospitals for ESBL production, using screening breakpoints for aztreonam and third generation cephalosporins, according to CLSI recommendations. Among these isolates, 155 were positive for the ESBL screening test, and 121 (78%) were confirmed by the clavulanic acid combination disk method. We found a high frequency of ESBL (24%) among Enterobacteriaceae, with a frequency of 57.4% for Klebsiella pneumoniae, 21.4% for Klebsiella oxytoca, and 7.2% for E. coli. In other members of Enterobacteriaceae, non-Klebsiella and non-E. coli, the prevalence was 21.6%. Ceftriaxone and cefotaxime showed a higher sensitivity in the screening test (99.2%) when compared to ceftazidime, aztreonam and cefpodoxime. However, cefotaxime/cefotaxime plus clavulanic acid showed a higher sensitivity in the confirmatory test (96.7%).
Nogueira
Keite da Silva
Kda S
Laboratory of Bacteriology, Federal University of Parana, Curitiba, PR, Brazil .
Higuti
Ilma Hiroko
IH
do Nascimento
Agnaldo José
AJ
Terasawa
Larissa Bail
LB
de Oliveira
Simone
S
Matos
Adriana Pereira
AP
de Souza
Helena Aguilar Peres Homem de Mello
HA
Cogo
Laura Lúcia
LL
Dalla Costa
Libera Maria
LM
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001398:Aztreonam / Q000494:pharmacology; D001938:Brazil; D002511:Cephalosporins / Q000494:pharmacology; D019818:Clavulanic Acid / Q000494:pharmacology; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification; D006785:Hospitals, University; D006801:Humans; D008826:Microbial Sensitivity Tests; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D019818:Clavulanic Acid; D001618:beta-Lactamases; D001398:Aztreonam