Streptococcus anginosus of the urogenital tract: evidence of the same strain across anatomical sites of the same females.

BACKGROUND: Streptococcus anginosus has been found to colonize multiple anatomical sites of the human body, including the oral cavity, gastrointestinal tract, skin, vagina, blood, and urinary tract. It is frequently isolated from catheterized urine samples obtained from adult females most often with lower urinary tract symptoms, but also on occasion from those without symptoms. Our prior genome analysis of 166 S. anginosus genomes identified two distinct groups, one - which we here call group Urinae - exhibits a tropism for the urinary tract.

RESULTS: Here we sequenced 100 isolates collected from different urogenital sites, including isolates from urine (both catheterized and voided) samples, urethral swabs, perineal swabs, vaginal swabs, and a foreskin swab. These sequenced isolates, as well as 15 isolates previously sequenced by our group, were collected from 50 unique individuals, with isolates from multiple anatomic sites for 26 of these individuals. The majority (89.57%) of the isolates were representatives of the Urinae group and were found in all sample types. Expanding our prior statistical method, we determined that, for 11 females, the same strain of Urinae was isolated from more than one of the urogenital sites.

CONCLUSIONS: The identification of S. anginosus group Urinae strains from all urogenital sites sampled signifies that the tropism of this group is not restricted to the urinary tract. Rather, it seems to be a common constituent of the urogenital tract. The identification of the same strain shared across urogenital sample sites from the same individual suggests that the female urogenital sites in fact have interconnected microbiota.