RESUMEN
Streptococcus mitis/oralis group isolates with reduced carbapenem susceptibility have been reported, but its isolation rate in Japan is unknown. We collected 356 clinical α-hemolytic streptococcal isolates and identified 142 of them as S. mitis/oralis using partial sodA sequencing. The rate of meropenem non-susceptibility was 17.6% (25/142). All 25 carbapenem-non-susceptible isolates harbored amino acid substitutions in/near the conserved motifs in PBP1A, PBP2B, and PBP2X. Carbapenem non-susceptibility is common among S. mitis/oralis group isolates in Japan.
Asunto(s)
Carbapenémicos , Streptococcus mitis , Proteínas de Unión a las Penicilinas/genética , Streptococcus mitis/genética , Streptococcus mitis/metabolismo , Carbapenémicos/farmacología , Japón , Sustitución de Aminoácidos , Pruebas de Sensibilidad Microbiana , Streptococcus/metabolismo , Estreptococos Viridans/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismoRESUMEN
We evaluated the feasibility and efficacy of a commercially available methicillin-resistant Staphylococcus aureus (MRSA)-selective agar, chromID(™) MRSA, to detect group B streptococci with reduced penicillin susceptibility (PRGBS) in this study. The results showed 72.4% (21/29) sensitivity and 98.4% (60/61) specificity to detect PRGBS using this method.
Asunto(s)
Técnicas Bacteriológicas/métodos , Medios de Cultivo/química , Infecciones Estreptocócicas/diagnóstico , Streptococcus agalactiae/efectos de los fármacos , Streptococcus agalactiae/aislamiento & purificación , Resistencia betalactámica , Agar , Sensibilidad y EspecificidadRESUMEN
Penicillins remain first-line agents for treatment of group B Streptococcus (Streptococcus agalactiae; GBS) infections; however, several reports have confirmed the existence of GBS with reduced penicillin susceptibility (PRGBS). Because no selective agar plates for detection of PRGBS are available to date, in this investigation, we developed the selective agar plate for detection of PRGBS. We used 19 genetically well-confirmed PRGBS isolates and 38 penicillin-susceptible GBS isolates identified in Japan. For preparation of trial PRGBS-selective agar plates, we added 1 of antimicrobial agents (among oxacillin, ceftizoxime, and ceftibuten) to a well-established GBS-selective agar plate. Among 12 trial PRGBS-selective agar plates, Muller-Hinton agar containing 128 µg/mL ceftibuten with 5% sheep blood, 8 µg/mL gentamicin, and 12 µg/mL nalidixic acid was the most appropriate selective agar for PRGBS, showing 100% sensitivity and 81.6% specificity. In cases of potential nosocomial spread of PRGBS, the selective agar plate could be useful and reliable.