Antimicrobial Susceptibility Profile of Clinical Isolates of Peptostreptococcus anaerobius

Gram-positive anaerobic cocci (GPAC) which are commonly known as Peptococci or Peptostreptococci belong to the genus Peptostreptococcus. Peptostreptococcus anaerobius is one of the most common GPAC known to be associated with infections of the abdominal cavity and the female genitourinary tract. The present study aims at determining the antimicrobial susceptibility profile of P. anaerobius isolates against various antimicrobials. This study was conducted over a period of three years from January 2015 to December 2017 in the Department of Microbiology of a tertiary care teaching hospital. Specimens like pus aspirates, soft tissue and body fluids were included in the study. P. anaerobius isolates were identified by standard methods and confirmed by automated mass spectrometry. Minimum inhibitory concentration was determined by the reference agar dilution method for different anti-anaerobic agents. A total of 30 P. anaerobius isolates were obtained from various infections with majority (n=21, 70%) of the isolates being recovered from infections of the anatomical sites below the waistline. All isolates showed excellent anti-anaerobic activity against metronidazole, penicillin G, cefoxitin and chloramphenicol. Clindamycin resistance was noted in 53.3% (n=16) of P. anaerobius isolates. None of the isolates were b-lactamase producers. Metronidazole which is considered as the empirical therapy of choice for anaerobic infections was found to have excellent activity.Significant resistance was noted towards clindamycin which is commonly used as an alternative to metronidazole in suspected anaerobic infections. Routine sensitivity testing of clinical isolates of anaerobes seems to be the need of the hour for effective patient management.