Anorectal carriage as a possible primary source of vaginal colonization by group B Streptococcus was investigated. The study was performed during two separate periods and included 789 pregnant women and 422 neonates. Specimens from multiple sites were obtained for culture from all women and infants and were streaked onto blood agar plates containing 8 mug of gentamicin sulfate/ml and 15 mug of nalidixic acid/ml, which allow selective growth of streptococci. Cultures positive for group B streptococci were obtained from 162 (20.5%) of the pregnant women and from 50 (11.8%) of the neonates. Rectal cultures were positive for streptococci in 142 (17.9%) of the women, and vaginal cultures gave positive results in 81 (10.2%). The higher incidence of positive results in rectal as opposed to vaginal cultures (ratio of 2:1) was encountered during all phases of the study. This finding suggests that the gastrointestinal tract may be the primary site of colonization by group B Streptococcus and that vaginal colonization may represent contamination from this source.

This study was designed to determine whether Staphylococcus saprophyticus was an important cause of urinary tract infection (UTI), as has been reported by European, but not by American, investigators, S. saprophyticus was the second most common cause of UTI in young (mean age, 20 years), sexually active female outpatients without known preexisting kidney disease or preceding manipulation of the urinary tract. Most cases presented as acute cystitis, but frank pyelonephritis and UTI in pregnant females were observed. The organism was rarely found as a contaminant in urine cultures. When present in the mucocutaneous flora of the anal-urogenital area, the organism was significantly associated with UTI by the same organism. These results show that S. saprophyticus should be accepted as an important urinary tract pathogen of young female patients in the United States. A simple adequate laboratory identification may be based on resistance to novobiocin (disk diffusion test), absence of hemolysis and coagulase, and intense pigment production (65% of strains yellow, 35% white).

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Factors affecting the adherence of group B streptococci to human vaginal epithelial cells in vitro were examined. Maximal adherence was achieved within 15 min of incubation of bacteria with epithelial cells. Adherence was temperature and pH dependent; maximal adherence occurred at 370C and pH 5.5. Killing of streptococci with ultraviolet light or penicillin did not affect adherence. Similarly, adherence was not altered by preincubating epithelial cells at 650C for 30 mi. Thus neither bacterial nor epithelial cell viability appears to be a prerequisite for adherence. Preincubation of streptococci at 650C for 30 min resulted in a marked decrease in adherence, whereas preincubation of group B streptococci with neuraminidase was associated with a significant increase in adherence. The adherence of strains belonging to five different group B streptococcal serotypes was not altered by group-specific or type-specific rabbit antisera. These findings suggest that the site for adherence on the bacterial cell wall is heat sensitive and is masked by sialic acid, but is not related to either group-specific or type-specific antigens.

The 0-1 bacteriophage test of Cherry et al. (1954) for the presumptive identification of salmonellae in the diagnostic laboratory was investigated. A phage lysate with a titer of 1012 plaque-forming units per ml was found to be optimal. This preparation lysed 98.2% of Salmonella strains tested, while maintaining its high specificity for salmonellae. Gram-negative organisms other than salmonellae were resistant to the 0-1 phage; however, 5.9% of Escherichia coli strains tested were susceptible. The 0-1 phage test is a simple, rapid, inexpensive, sensitive, and specific procedure for the identification of salmonellae in the diagnostic laboratory. A presumptive identification is obtained 1 day earlier than with conventional biochemical tests.

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