RESUMO
We report on the first isolation of an extended-spectrum beta-lactamase-producing Leclercia adecarboxylata strain from the bloodstream in a 58-year-old man with acute myeloid leukemia. The strain, resistant to ceftazidime, cefotaxime, and aztreonam, produces the SHV-12 beta-lactamase, one of the most common variants found in Italian nosocomial isolates of Enterobacteriaceae.
Assuntos
Sangue/microbiologia , Infecções por Enterobacteriaceae/microbiologia , Enterobacteriaceae/isolamento & purificação , Leucemia Mieloide/complicações , Resistência beta-Lactâmica , beta-Lactamases/metabolismo , Doença Aguda , Antibacterianos/farmacologia , Aztreonam/farmacologia , Bacteriemia/microbiologia , Ceftazidima/farmacologia , Meios de Cultura , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/enzimologia , Humanos , Leucemia Mieloide/microbiologia , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-IdadeRESUMO
Seven Klebsiella pneumoniae and four Klebsiella oxytoca clinical isolates with different levels of resistance to ciprofloxacin were studied. Mutations in the topoisomerase genes were found in almost all strains, but the contribution of a multidrug efflux system homologous to AcrAB in Escherichia coli was also observed. Overexpression of this efflux system was demonstrated by immunoblotting with antibodies against E. coli AcrA.
Assuntos
Anti-Infecciosos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Klebsiella oxytoca/genética , Klebsiella pneumoniae/genética , Ciprofloxacina/metabolismo , Ciprofloxacina/farmacologia , DNA Topoisomerases Tipo I/genética , Klebsiella oxytoca/efeitos dos fármacos , Klebsiella oxytoca/metabolismo , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/metabolismo , Testes de Sensibilidade MicrobianaRESUMO
A study was conducted to evaluate the new VITEK 2 system (bioMérieux) for identification and antibiotic susceptibility testing of gram-positive cocci. Clinical isolates of Staphylococcus aureus (n = 100), coagulase-negative staphylococci (CNS) (n = 100), Enterococcus spp. (n = 89), Streptococcus agalactiae (n = 29), and Streptococcus pneumoniae (n = 66) were examined with the ID-GPC identification card and with the AST-P515 (for staphylococci), AST-P516 (for enterococci and S. agalactiae) and AST-P506 (for pneumococci) susceptibility cards. The identification comparison methods were the API Staph for staphylococci and the API 20 Strep for streptococci and enterococci; for antimicrobial susceptibility testing, the agar dilution method according to the procedure of the National Committee for Clinical Laboratory Standards (NCCLS) was used. The VITEK 2 system correctly identified to the species level (only one choice or after simple supplementary tests) 99% of S. aureus, 96.5% of S. agalactiae, 96.9% of S. pneumoniae, 92.7% of Enterococcus faecalis, 91.3% of Staphylococcus haemolyticus, and 88% of Staphylococcus epidermidis but was least able to identify Enterococcus faecium (71.4% correct). More than 90% of gram-positive cocci were identified within 3 h. According to the NCCLS breakpoints, antimicrobial susceptibility testing with the VITEK 2 system gave 96% correct category agreement, 0.82% very major errors, 0.17% major errors, and 2.7% minor errors. Antimicrobial susceptibility testing showed category agreement from 94 to 100% for S. aureus, from 90 to 100% for CNS, from 91 to 100% for enterococci, from 96 to 100% for S. agalactiae, and from 91 to 100% for S. pneumoniae. Microorganism-antibiotic combinations that gave very major errors were CNS-erythromycin, CNS-oxacillin, enterococci-teicoplanin, and enterococci-high-concentration gentamicin. Major errors were observed for CNS-oxacillin and S. agalactiae-tetracycline combinations. In conclusion the results of this study indicate that the VITEK 2 system represents an accurate and acceptable means for performing identification and antibiotic susceptibility tests with medically relevant gram-positive cocci.