In vitro bactericidal activities of antimicrobial agents and morphologic changes on Prevotella bivia.

Prevotella bivia is common in pelvic inflammatory diseases. Parenteral antimicrobial agents have been widely used against those infections. We investigated the bactericidal activities of three cephalosporins, i.e. cefluprenam (CFLP), ceftazidime (CAZ) and cefotaxime (CTX) and of two other antimicrobial agents, i.e. clindamycin (CLDM) and imipenem (IPM) against P. bivia. We also investigated the in vitro morphological changes induced by these agents in P. bivia. Cephalosporins exhibited bactericidal activities against P. bivia and induced time- and concentration-dependent morphological changes in P. bivia (filamentation). CLDM and IPM also had bactericidal activities, but induced different morphologic alterations: formation of spheroblasts and lysis. These results confirm the fact that each antimicrobial agent has characteristic aspects.