RESUMEN
During a national surveillance program on Group B streptococci (GBS) maternal carriage and neonatal infections, a GBS strain isolated from a pregnant woman's vagino-rectal swab was non typable by either serological or molecular methods. Further molecular characterization demonstrated that the strain lacked the entire capsular locus, possibly by a recombination event that excised a 14,1 Kbase pairs genomic fragment extending from the regulatory protein cpsX gene to the neuA gene. The natural loss of the capsular locus by GBS isolated from a human has never been described so far. Such an event, while possibly a dead-end from the evolutionary point of view, leaves a still able-to-colonize organism unrecognizable by the vaccines currently under development.
Asunto(s)
Cápsulas Bacterianas/genética , Polisacáridos Bacterianos/metabolismo , Streptococcus agalactiae/genética , Cartilla de ADN , Femenino , Humanos , Embarazo , Complicaciones Infecciosas del Embarazo/microbiología , ARN Ribosómico 16S/genética , Mapeo Restrictivo , Análisis de Secuencia de ADN , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/clasificación , Streptococcus agalactiae/aislamiento & purificación , Vagina/microbiologíaRESUMEN
During an area-based study, 75 group B streptococcus (GBS) strains isolated both from early-onset disease (EOD, 37 strains) and from late-onset disease (LOD, 38 strains) were analysed for serotype, pulsed field gel electrophoresis (PFGE) and multilocus sequence typing profiles, protein markers and antibiotic resistance. Serotype III, possessing the rib gene, was the most frequent (54 strains, 72%) and responsible for 89.5% and 54% of LOD and EOD, respectively. Forty-six serotype III strains belonged to the same PFGE type and clonal complex 17, already described as an over-represented clone in neonatal invasive GBS infections. Other serotypes were Ia (9.3%), II (6.7%), Ib (5.3%), V (5.3%) and IV (1.3%). Seventeen PFGE groups were identified comprising strains with related sequence types; conversely, strains displaying the same sequence type could belong to different PFGE groups. When both neonate and maternal strains from vaginorectal swabs and/or milk were available (eight cases), they were indistinguishable. Resistance to erythromycin (12%) was associated with a constitutive resistance to clindamycin in five cases (four carrying the erm(B) gene and one both the erm(B) and mef(E) genes) and with an inducible clindamycin resistance in two cases (one possessing the erm(A) gene, the other the erm(T) gene). Two isolates displayed the M phenotype (mef(E) gene). All strains but five were resistant to tetracycline, mostly mediated by the tet(M) gene (97.1%). The study underlined the importance of an active surveillance system for the elucidation of a GBS population structure causing neonatal infections and allowed the detection of rare antibiotic resistance determinants [erm(T)].
Asunto(s)
Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/patología , Streptococcus agalactiae/aislamiento & purificación , Antibacterianos/farmacología , Proteínas Bacterianas/análisis , Proteínas Bacterianas/genética , Clindamicina/farmacología , Análisis por Conglomerados , Dermatoglifia del ADN , ADN Bacteriano/genética , Farmacorresistencia Bacteriana , Electroforesis en Gel de Campo Pulsado , Eritromicina/farmacología , Genotipo , Humanos , Lactante , Recién Nacido , Italia/epidemiología , Pruebas de Sensibilidad Microbiana , Epidemiología Molecular , Tipificación de Secuencias Multilocus , Fenotipo , Proteoma/análisis , Serotipificación , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/clasificación , Streptococcus agalactiae/genética , Streptococcus agalactiae/inmunología , Tetraciclina/farmacologíaRESUMEN
Enterococci are opportunistic pathogens which today represent one of the leading causes of nosocomial infections. We have examined a collection of 52 Enterococcus faecalis isolated from orthopedic infections to determine if they were characterized by a specific pattern of virulence factors. The isolates were evaluated for biofilm formation, presence of genes coding the enterococcal surface protein (esp) and gelatinase (gelE), as well as for gelatinase production. While the rate of esp-positive isolates was comparable to that found among strains from other clinical sources, we found a significantly higher rate of strong biofilm formers and gelatinase producers. Particularly high was the rate of gelE-carrying strains expressing the gene. Data suggest that these two factors in particular may play an important role in enterococcal infections associated with biomaterials.
Asunto(s)
Biopelículas/crecimiento & desarrollo , Enterococcus faecalis/patogenicidad , Gelatinasas/metabolismo , Infecciones por Bacterias Grampositivas/microbiología , Equipo Ortopédico/microbiología , Factores de Virulencia , Enterococcus faecalis/clasificación , Enterococcus faecalis/genética , Enterococcus faecalis/aislamiento & purificación , Gelatinasas/genética , Genes Bacterianos , Infecciones por Bacterias Grampositivas/diagnóstico , Virulencia/genéticaRESUMEN
BACKGROUND & OBJECTIVES: An association between the onset or recrudescence of some neuropsychiatric disorders in children such as tic disorders and group A streptococcal (GAS) infections has been suggested. No information is available on the characterization of GAS strains associated with such disorders. The present study was undertaken to characterize the GAS strains isolated from children with tic disorders and to determine and correlate the antistreptolysin O (ASO) titre with the presence of GAS. METHODS: During 1996-2001, 368 children with tic disorders were investigated for possible exposition to streptococcal antigens. All children, at the time of the first visit and during the follow up visits were apparently healthy and showed no clinical evidence of streptococcal infections or post streptococcal sequelae. Blood and throat swab samples were collected and serological and bacteriological tests done. The isolates obtained were investigated for T pattern, M protein and emm type, as well as for the production of protease. RESULTS: Of the 800 throat swabs studied 100, corresponding to 67 patients, were positive for GAS; 49 children were found positive for GAS only once during the study, 18 had more than one sample positive for different serotypes, 8 were positive twice or more for the same type. ASO titres of these children were, in general, elevated. Five types, namely type M12, 3, 13, 11, 1, accounted for 39 per cent of the isolates, M12 being the most common, but a large number of different types were also found. A large number of isolates (62%) showed an elevated prodution of protease in the casein plate assay. INTERPRETATION & CONCLUSION: Despite the high level of ASO titres found, the results were not in favour of a particular virulence or invasivity of the isolates. Only a few colonies per sample were found indicating that factors different from the microbial virulence play a role in this type of disease.
Asunto(s)
Streptococcus pyogenes/aislamiento & purificación , Trastornos de Tic/microbiología , Adolescente , Niño , Preescolar , Femenino , Humanos , Masculino , Streptococcus pyogenes/clasificaciónRESUMEN
In late May 1994, following reports of an outbreak of group A beta-haemolytic streptococcus (GAS) in the United Kingdom, the Istituto Superiore di Sanita (ISS) set up a surveillance system for systemic invasive GAS disease. The surveillance system was als
Asunto(s)
Infecciones Estreptocócicas/epidemiología , Streptococcus pyogenes , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Bacteriemia/epidemiología , Niño , Preescolar , Fascitis Necrotizante/epidemiología , Humanos , Lactante , Italia/epidemiología , Meningitis Bacterianas/epidemiología , Persona de Mediana Edad , Miositis/epidemiología , Serotipificación , Choque Séptico/epidemiología , Infecciones Estreptocócicas/microbiología , Streptococcus pyogenes/clasificaciónRESUMEN
The efficacy and safety of a 3-day course of azithromycin oral suspension (10 mg/kg of body weight once daily) were compared with those of penicillin V (50,000 U/kg/day in two divided doses) in children aged 3 to 12 years for the treatment of symptomatic pharyngitis caused by the group A beta-hemolytic streptococcus (GABHS). For the 154 evaluable patients, the original infecting strain of GABHS was eliminated at the end of follow-up (34 to 36 days after treatment started) from 67 (85.8%) of 78 penicillin-treated patients and 41 (53.9%) of 76 azithromycin-treated patients (P < 0.0001). Overall clinical success was achieved in 71 (91.0%) of 78 penicillin V-treated patients and 57 (75.0%) of 76 azithromycin-treated patients (P < 0.05). Potential drug-related adverse events were reported for 5.5 and 8.6% of the penicillin V- and azithromycin-treated patients, respectively (P = 0.6). In the present study, a once-daily (10 mg/kg), 3-day oral regimen of azithromycin was as safe as a 10-day course of penicillin but did not represent an effective alternative to penicillin for the treatment of GABHS pharyngitis, even for those children with azithromycin-susceptible strains.