Prevalence of cefotaxime resistance in group B streptococcus isolates from Osaka, Japan

First Molecular Characterization of Group B Streptococci with Reduced Penicillin Susceptibility

“…In the present study, however, the 14 clinical isolates, which were donated by geographically separate hospitals and which were not genetically related, obviously showed properties of "insusceptibility" to penicillin G. The MIC measurements revealed that the 14 clinical isolates investigated have MICs indicating penicillin-insusceptible properties (MICs, 0.25 to 1.0 g/ml) greater than the MIC criteria for "susceptibility" to penicillin G (MICs, Յ0.12 g/ml) for beta-hemolytic streptococci established by the CLSI. Previously, although several susceptibility test studies have indeed mentioned the existence of ␤-lactaminsusceptible GBS strains (3,8,19), none have intensively identified the GBS strains and investigated the resistance mechanisms on a molecular basis. Therefore, we definitely reidentified the GBS clinical isolates using several different methods, including Gram staining, 16S rRNA gene fingerprinting, biochemical analysis, the CAMP test, and surface antigen analysis.…”

Genetic Heterogeneity in pbp Genes among Clinically Isolated Group B Streptococci with Reduced Penicillin Susceptibility

“…Although this study did not focus on quinolone-resistant strains, a trend toward increasing fluoroquinolone MICs has clearly been noted among recently emerged strains. However, confirmed resistance to ␤-lactams, including penicillin, has not been recognized among GBS isolates, although strains with reduced susceptibilities have been described in several reports (7,16,22). This is exemplified by the fact that the CLSI lists interpretive criteria for susceptibility for strains of beta-hemolytic streptococci, that is, MICs of Յ0.12 g/ml, Յ0.25 g/ml, and Յ0.5 g/ml, only for penicillin, ampicillin, and cephems (cefotaxime, cefepime, and ceftriaxone) and meropenem, respectively; and it comments that strains with MICs greater than those breakpoints have not been observed (5).…”

“…Resistance to this agent has so far not been reported among GBS isolates, while survey studies have shown a high prevalence of resistance to macrolides, followed by fluoroquinolones, among invasive and noninvasive isolates (3,9,14,18,24,40). However, a trend toward an increase in the MICs of ␤-lactam antibiotics has occasionally been noted in recent reports (7,16,22), although no detailed analysis of the molecular mechanism associated with the loss of susceptibility had been conducted before the recently described studies (6,19). This phenomenon elicits concern for the future prevalence of GBS strains with increased resistance to ␤-lactams, as has been noted for Streptococcus pneumoniae, in which penicillin-intermediate resistant pneumococcal strains were reported in the late 1960s (1,13), followed by the reporting of more highly resistant strains (MICs, Ն2 g/ml) whose drug resistance expanded not only to ␤-lactams but also to other antimicrobial agents in the late 1970s (2,20).…”

Clinical Microbiology of Bacterial and Fungal Sepsis in Very-Low-Birth-Weight Infants

“…Emergence of penicillin resistance among GBS has not become a problem in the United States; however, approximately 20 to 40% of GBS isolates in some centers are resistant to clindamycin or erythromycin (particularly type V strains) (261,307). A recent report from Japan describes clinical GBS isolates with intermediate sensitivity and with resistance to penicillin (329), but the clinical significance of this finding is unclear. Because of the risk of emerging resistance and the failure of intrapartum antibiotics to prevent GBS LONS as well as some cases of EONS, efforts to develop a multivalent GBS vaccine are ongoing (24).…”