Combined use of phage typing, enterococcinotyping and species differentiation of group D streptococci as an effective epidemiological tool.

Ninety-five group D streptococcal isolates from the feces of 95 healthy persons were compared with 157 group D streptococcal isolates from 38 patients of the surgical intensive care unit (sICU). The typing systems consisted of phage typing, enterococcinotyping and species differentiation. Strains isolated from fecal specimens showed high individuality (66 combination types) whereas strains from the sICU revealed strongly uniform types (32 combination types, three types comprised 83 isolates, i.e. 52.8%). Endogenous colonization was demonstrated by isolation of strains from different locations (throat, trachea, wounds, blood, urine, drains, catheters, and vaginal swabs) from the same patient, and routes of transmission of the same strains to several patients were traced. The combination of three systems revealed a good discrimination between isolates of fecal and extrafecal specimens. The investigation detected highly preferred types in strains of extrafecal origin which were rarely isolated from fecal specimens. This may indicate that only strains with special characters preferably were able to colonize extraintestinal sites.