Streptococcus agalactiae in pregnant women: phenotypic and genotypic characters.

OBJECTIVE: Streptococcus agalactiae (GBS) is considered a leading cause of neonatal sepsis. We evaluated the phenotypic and genotypic characters of 73 S. agalactiae strains isolated from different women at the 35-37 weeks of pregnancy. METHODS: Isolates were characterized by serotyping (direct agglutination) and by pulsed-field-gel-electrophoresis (PFGE). Resistance to antimicrobials (penicillin, macrolides, lincosamides, quinolones and tetracyclines) was assessed. RESULTS: All isolates were serologically typeable and ascribable to one of the six tested serotypes (Ia, Ib, II, III, IV, and V) and many strains of the same serotype were genetically heterogeneous. Strains belonging to serotypes III, V and Ia were the most prevalent and the most resistant to macrolides. CONCLUSIONS: This work reports GBS colonization rate (about 18%) and the prevalent capsular serotypes among pregnant women in Turin (Italy). Penicillin and erythromycin can be still considered the first and second choice drugs for prophylaxis and treatment of early-onset GBS infections in our district. The relevance of phenotypic and genotypic characterization of strains to monitor and control Streptococcus agalactiae infections is briefly discussed.

Discrepancy between Helicobacter pylori stool antigen assay and urea breath test in the detection of Helicobacter pylori infection.

BACKGROUND: The reference diagnostic methods available for detection of Helicobacter pylori infection are either invasive (histology) or expensive and highly sophisticated (Urea Breath Test). A new enzyme immunoassay, which can be easily performed in any laboratory, has been developed to detect Helicobacter pylori in stool specimens (HpSA-Meridian Diagnostics, Cincinnati, USA). Aim of the study was to compare HpSA to Urea Breath Test. PATIENTS AND METHODS: A total of 125 patients (52 never treated for Helicobacter pylori infection and 73 after Helicobacter pylori eradication therapy) referring to our Department, underwent both tests within two weeks. RESULTS: Contrasting results between the two tests were found in 30% of cases: in 19% of the untreated patients and in 37% of the treated patients (p<0.001). The main discrepancy consisted in positive HpSA associated with negative Urea Breath Test. Mean HpSA value in such conditions was 0.273 optical density, while in patients with both positive tests, it was 1.192 optical density. In untreated, but not in treated patients, raising the HpSA cut off value significantly decreased the percentage of conflicting results. CONCLUSIONS: Some disagreement was detected between HpSA and Urea Breath Test results, especially in treated patients. Possible explanations for our findings are a low HpSA cut off value together with the identification of Helicobacter pylori coccoid forms by the immunoassay but not by the urease based Urea Breath Test. The higher percentage of discrepancy detected in treated patients might support this hypothesis.