The frequency of genes encoding three putative group B streptococcal virulence factors among invasive and colonizing isolates

BACKGROUND: Group B Streptococcus (GBS) causes severe infections in very young infants and invasive disease in pregnant women and adults with underlying medical conditions. GBS pathogenicity varies between and within serotypes, with considerable variation in genetic content between strains. Three proteins, Rib encoded by rib, and alpha and beta C proteins encoded by bca and bac, respectively, have been suggested as potential vaccine candidates for GBS. It is not known, however, whether these genes occur more frequently in invasive versus colonizing GBS strains. METHODS: We screened 162 invasive and 338 colonizing GBS strains from different collections using dot blot hybridization to assess the frequency of bca, bac and rib. All strains were defined by serotyping for capsular type, and frequency differences were tested using the Chi square test. RESULTS: Genes encoding the beta C protein (bac) and Rib (rib) occurred at similar frequencies among invasive and colonizing isolates, bac (20% vs. 23%), and rib (28% vs. 20%), while the alpha (bca) C protein was more frequently found in colonizing strains (46%) vs, invasive (29%). Invasive strains were associated with specific serotype/gene combinations. CONCLUSION: Novel virulence factors must be identified to better understand GBS disease

Inibição da formação de abscesso abdominal em rato: mortalidade por sepse Inhibition of abdominal abscess formation in rat: Mortality by sepsis

RACIONAL: Atribui-se aos abscessos intra-abdominais e às aderências peritoniais a função de isolar os processos sépticos e proteger o organismo da bacteremia. Por outro lado, esses fenômenos também dificultam o afluxo de fatores imunitários e antibióticos para a região infectada. OBJETIVO: Avaliar o efeito da prevenção de abscessos na sobrevida após peritonite bacteriana. MÉTODOS: Foram estudados 30 ratos Wistar machos que receberam solução de fezes a 50% intra-abdominal e que foram distribuídos em três grupos (n = 10). Grupo 1: controle (solução de fezes); grupo 2: solução de fezes mais solução salina a 0,9%; grupo 3: solução de fezes mais carboximetilcelulose a 1%, para inibir a formação de aderências. Os três grupos foram divididos em dois subgrupos (n = 5): subgrupo A: nova laparotomia, após 4 dias, para inspeção da cavidade abdominal; e subgrupo B: acompanhamento durante 30 dias para avaliação da mortalidade e da causa de morte. A análise estatística utilizou o teste exato de Fisher. RESULTADOS: O acréscimo de solução salina a 0,9% não aumentou a mortalidade do grupo. Entretanto, no grupo em que se acrescentou a solução de carboximetilcelulose, houve menor formação de abscessos, que também foram mais tênues e a mortalidade aumentou em relação ao grupo controle. CONCLUSÃO: A inibição na formação de aderências peritoniais e de abscessos acompanha-se de maior mortalidade decorrente do processo séptico intra-abdominal generalizado

The genetic diversity and phenotypic characterisation of Streptococcus agalactiae isolates from Rio de Janeiro, Brazil

Streptococcus agalactiae isolates are more common among pregnant women, neonates and nonpregnant adults with underlying diseases compared to other demographic groups. In this study, we evaluate the genetic and phenotypic diversity in S. agalactiae strains from Rio de Janeiro (RJ) that were isolated from asymptomatic carriers. We analysed these S. agalactiae strains using pulsed-field gel electrophoresis (PFGE), serotyping and antimicrobial susceptibility testing, as well as by determining the macrolide resistance phenotype, and detecting the presence of the ermA/B, mefA/E and lnuB genes. The serotypes Ia, II, III and V were the most prevalent serotypes observed. The 60 strains analysed were susceptible to penicillin, vancomycin and levofloxacin. Resistance to clindamycin, chloramphenicol, erythromycin, rifampin and tetracycline was observed. Among the erythromycin and/or clindamycin resistant strains, the ermA, ermB and mefA/E genes were detected and the constitutive macrolides, lincosamides and streptogramin B-type resistance was the most prevalent phenotype observed. The lnuB gene was not detected in any of the strains studied. We found 56 PFGE electrophoretic profiles and only 22 of them were allocated in polymorphism patterns. This work presents data on the genetic diversity and prevalent capsular serotypes among RJ isolates. Approximately 85% of these strains came from pregnant women; therefore, these data may be helpful in developing future prophylaxis and treatment strategies for neonatal syndromes in RJ