Actividad sialidasa en mujeres con vaginosis bacteriana / Sialidase activity in women with bacterial vaginosis

La vaginosis bacteriana (VB) es un síndrome caracterizado por el sobrecrecimiento bacteriano deflora endógena Gram negativa, que desplaza a la flora lactobacilar normal. Dentro de las enzimasbacterianas, las sialidasas han sido consideradas factores de virulencia de muchos microorganismos patógenosque colonizan las distintas mucosas. Su presencia en fluidos vaginales puede estar correlacionada con VB. Elpropósito de este estudio fue comprobar la actividad de dicha enzima en mujeres con este síndrome y sin evidenciaclínica de infección genital. Se estudiaron 112 mujeres (51 fueron pacientes con VB y 61 mujeres conflora colonizante habitual). Para la cuantificación de la actividad sialidasa se empleó la técnica basada en lahidrólisis enzimática de un derivado ácido del ácido metoxifenil acetil murámico. En la población estudiada seencontró que ambos grupos mostraron valores comprendidos entre 0.5 a 5.1 nmoles de metoxifenol, mientrasque 11 de 52 pacientes con VB (21.17%), registraron valores superiores a 5.1 nmoles. La presencia de actividadsialidasa solamente no es índice de VB, excepto para valores mayores de 5.5 nmoles de metoxifenol, producidosen la reacción enzimática.

Bacterial vaginosis (VB) is a syndromecharacterized by overgrowth of endogenous Gram negative bacterial flora and the lack of the normalflora. Within bacterial enzymes, sialidases have been considered a virulence factor of many pathogenic microorganismscolonizing the different mucous membranes. Their presence in vaginal discharges can be correlatedwith VB. The aim of this study was to detect the activity of this enzyme in women with this syndrome andwithout clinical evidence of genital infection. Out of a total 112 women studied, 51 were patients with VB andthe other 61 women presented normal vaginal flora. For the quantification of enzyme activity, the technique basedon the enzymatic hydrolysis of a derivative acid of the acetyl metoxifenil muramic acid was used. In the studiedpopulation both groups shared values from 0.5 to 5.1 nmoles of metoxifenol, whereas only 11 out of 52 patientswith VB (21.17%), registered more than 5.1 nmoles. The presence of sialidase activity is not enough to confirmVB, except for values greater than 5.5 nmoles of the metoxifenol produced in the enzymatic reaction.

Phenotypic and getotypic study of Streptococcus agalactiae in vagina of pregnant women in Argentina

Streptococcus agalactiae (GBS) is a leading cause of serious neonatal infection. In this study we determine the prevalence, serotype distribution and genomic diversity of GBS in vagina of pregnant women.Vaginal swabs of 531 pregnant women were cultured on Columbia Agar Base Blood, GBS Agar Base and Todd Hewitt Broth. GBS were characterized by group and type-specific agglutination. Genomic polymorphism was studied by random amplification of DNA (RAPD). Seventeen patients (3.2 percent) were positive for GBS, resulting serotype III the most frequent. RAPD detected 16 different RAPD profiles from 21 GBS studied, revealing a good discriminatory power. In this sense, this method showed different genotype from GBS serotype III recovered from successive samples of two patients, suggesting reinfection. In conclusion, the combination of RAPD and serotyping appear promising for epidemiological studies. Finally, findings of reinfection after therapy during pregnancy, led us to suggest performing prenatal GBS screening and intrapartum prophylaxis in order to reduce neonatal risk.

Characterization of clinical isolates of Streptococcus agalactiae by random amplified polymorphic DNA using degenerate oligonucleotides

Epidemioiogicai studies of Streptococcus agalactiae strains have been limited by the lack of sensitive and discriminatory methods for comparing clinical isolates. Serotyping, albeit a widely used methodology, has been shown to possess low capability to distinguish between epidemiologically related and unrelated isolates. We have employed here a random amplification of polymorphic DNA (RAPD) assay, using degenerate oligonucleotides as primers, to characterize S. agalactiae isolates from related or unrelated clinical samples. Epidemioiogically-related isolates (mother-infant pairs) showed identical profiles by this methodology. On the contrary, 12 epidemioiogically-unrelated isolates (ciassified into 5 different serotypes) resulted in ll distinct RAPD patterns. This suggests that the proposed modified RAPD assay provides a highly discriminatory tool for the analysis of genomic diversity among isolates from pathogenic organisms.

Esquema simplificado de identificacion de las especies de staphylococcus coagulasa-negativa aislados de infecciones humanas / Identificacion simplified scheme for coagulase-negative staphylococcus strains isolated from human infections

Neste trabalho se identificaram 100 cepas de estafilococos coagulasa negativa de diferentes mostras clínicas. Buscando a correlaçäo entre homologia de DNA e características fenotípicas foi dividido em 2 grandes grupos pela sensibilidade à novobiocina e agregando a detecçäo de beta-galactosidasa e oxidasa em que se determinou 4 grupos (quadro 1): grupo de espécies de S. epidermidis, grupo de espécies de S.simulans: grupo de espécies de S. sapiophyticus e grupo de espécie de S. sciuri que säo factíveis de resolver em todo laboratório de microbiologia clínica. Por agregado de outras provas simples: detecçäo de ureasa, fosfatasa alcalina e beta-glucosidasa e detecçäo de aeróbica de acidez de maltosa, trehalosa e manitol se determinam as espécies de grupo S. epidermidis (quadro 2). Geralmente dada a maior frequência do S. epidermidis suficiente somente a detecäo de ureasa e fosfatasa. As espécies do grupo S. simulans se identificam com a determinaçäo de ureasa: fosfatasa alcalina e acidez de manitol (quadro 3): com a realizaçäo de ureasa e acidificaçäo de sacarosa e arabinosa se estabelece as espécies do grupo S. saprophyticus e unicamente por meio da rafinosa as espécies do grupo S. sciuri (quadro 5). A correlaçäo destas mínimas provas obtidas em nossas determinaçöes com as numerosissimas realizadas segundo apresenta o Manual de Bergey 9a. ediçäo, nos permite considerar a aplicabilidade deste esquema simples e rápido para diferenciar as espécies coagulasa negativa do gênero Staphyloccocus na maioria dos laboratórios de bacteriologia clínica