RESUMO
Susceptibility to penicillin, vancomycin, imipenem, streptomycin, kanamycin and gentamicin was tested in 130 clinical isolates of Enterococcus spp. by an agar dilution method. Penicillin resistance (MIC > 8 mg/l) was only observed among strains of Enterococcus faecium and Enterococcus raffinosus. Thirty-nine percent of the penicillin-resistant enterococci showed low-level resistance to at least one of the three aminoglycosides tested (gentamicin, kanamycin and streptomycin). Six Enterococcus strains (5 E. faecium and 1 E. raffinosus) with low-level resistance to gentamicin and different MICs for penicillin were tested for antibiotic synergy using time-killing curves. When penicillin concentrations equal to or higher than the MICs were used, synergism was established, even when highly penicillin-resistant strains (MIC > 200 mg/l) were tested. No synergy was observed when penicillin concentrations were below the MICs.
Assuntos
Antibacterianos/farmacologia , Enterococcus/efeitos dos fármacos , Resistência às Penicilinas , Penicilinas/farmacologia , Aminoglicosídeos , Sinergismo Farmacológico , Enterococcus/classificação , Humanos , Testes de Sensibilidade Microbiana , Especificidade da Espécie , Vancomicina/farmacologiaAssuntos
Cefuroxima/farmacologia , Testes de Sensibilidade Microbiana/métodos , Streptococcus pneumoniae/efeitos dos fármacos , Resistência às Cefalosporinas , Criança , Interpretação Estatística de Dados , Erros de Diagnóstico , Estudos de Avaliação como Assunto , Humanos , Testes de Sensibilidade Microbiana/estatística & dados numéricos , Infecções Pneumocócicas/tratamento farmacológico , Infecções Pneumocócicas/microbiologia , Streptococcus pneumoniae/isolamento & purificaçãoRESUMO
Four strains that were moderately susceptible to penicillin and/or ampicillin were found among 54 consecutive isolates of meningococci recovered from patients in one pediatric hospital in Argentina from October 1991 to December 1992. Disk diffusion tests performed with 2 U of penicillin failed to detect one strain. These findings suggest that attention should be paid to changes in the susceptibility patterns of meningococci in order to anticipate therapeutic failures in the future.
Assuntos
Ampicilina/farmacologia , Neisseria meningitidis/efeitos dos fármacos , Neisseria meningitidis/isolamento & purificação , Penicilinas/farmacologia , Argentina , Humanos , Meningite Meningocócica/sangue , Meningite Meningocócica/líquido cefalorraquidiano , Testes de Sensibilidade MicrobianaRESUMO
Six beta-lactamase-producing (Bla+) isolates of Enterococcus faecalis recovered over a 17-month period from an Argentinian pediatric hospital were found to have identical or almost identical chromosomal restriction patterns by pulsed-field gel electrophoresis, although the plasmid patterns were different. These isolates, like Bla+ enterococci in the United States, hybridized to a staphylococcal Bla gene probe. The presence of a single strain was somewhat surprising, since all isolates transferred Bla by conjugation.
Assuntos
Enterococcus faecalis/isolamento & purificação , Gentamicinas/farmacologia , Hospitais Pediátricos , beta-Lactamases/metabolismo , Argentina , Resistência Microbiana a Medicamentos , Enterococcus faecalis/enzimologia , Enterococcus faecalis/genética , Genoma Bacteriano , Humanos , Hibridização Genética , PlasmídeosRESUMO
Of the 90 strains of Enterococcus spp. isolated in an Argentine laboratory in the period from January to July 1989, three were identified as beta-lactamase-producing Enterococcus faecalis. According to the literature reviewed, these appear to be the first beta-lactamase-positive strains of Enterococcus isolated outside the USA. They differed from most beta-lactamase-producing strains already described in that they were susceptible to low concentrations of macrolides. All three strains were resistant to high concentrations of aminoglycosides.