Bacterial Interference by Group B Streptococci with Aerobic and Anaerobic Genital Tract Streptococci and Nonstreptococcal Aerobic Bacteria of the Female Genital Tract

Abstract

Target groups composed of 10 isolates of each of the following: S. viri dans, non-hemolytic streptococci not group B or D, group A streptococci, group B streptococci, peptostreptococci, coagulase-negative staphylococci, S. aureus, G. vagi nalis, E. coli, 9 enterococci, 9 group C or G streptococci; 7 lactobacilli and 7 diphtheroids were tested for inhibition by a test panel of a group of 10 or 41 group B streptococci (GBS). The GBS did not inhibit the growth of E. coli, coagulase nega tive staphylococci or S. aureus. They uniformly inhibited the groups A, B, C and G streptococci, lactobacilli and G. vaginalis. One isolate of diphtheroids was inhibited by 37 of 41 GBS; the other six isolates were uniformly inhibited. Variable inhibition was observed with the viridans streptococci, non-group B or D streptococci and en terococci; however, inhibition or noninhibition was uniform for a given isolate against the entire group B streptococcal test panel. The 23 isolates of the group B streptococci from neonates or adults with septicemia, did not differ from isolates from patients with only local disease in their ability to inhibit other species tested. The group B streptococci uniformly inhibited the aerobic lactobacilli, diphtheroids and G. vaginalis but had no effect on the coagulase-negative staphylococci, S. au reus or E. coli. These studies suggest that group B streptococci may be significant regulators of the female genital tract bacterial flora. (Thai J Obstet Gynaecol 1991;3:.45-52.)