B. G. Viswanath^1,, G. Jyothi Lakshmi¹, K. Nagamani¹, N. V. N. Reddy², G. Prakash Rao³, S. S. S. Srinivas³, Abhijeet M. Dashetwar⁴, Manjula⁵

Polymicrobial infections are predominated by anaerobes accompanied by facultative anaerobes and aerobes. Failure in providing appropriate antibiotic coverage for anaerobes in mixed aerobic, anaerobic infections and increasing resistance to antimicrobial agents among anaerobic bacteria lead to increased morbidity and mortality. Antibiotic resistance among clinically important obligate anaerobic bacteria is going unnoticed because of inadequate isolation, identification, and susceptibility testing. The increasing resistance among several species emphasizes the need to survey the susceptibility patterns of anaerobic organisms. The aims of this study were, firstly, to determine the most common anaerobic bacteria originating from several abscesses and, secondly, to analyze their susceptibility patterns. This prospective study included 50 samples, either pus aspirates or tissue sections from patients with deep visceral abscesses, attending surgical and medical departments over a period of one year. Both aerobic and anaerobic cultures were done, and all isolates were subjected to antibiotic sensitivity using Kirby-Bauer disc diffusion method. A total of 33 samples showed the presence of obligate anaerobes with a rate of isolation of 66%.The obligate anaerobes isolated were Bacteroides, Prevotella, Fusobacterium, Porphyromonas, Peptococcus, Peptostreptococcus and Bifidobacterium species. Bacteroides showed resistance to penicillin G (76.9%), ciprofloxacin (61.5%), erythromycin (61.5%), metronidazole (46.1%), amoxicillin & clavulanic acid (46.1%) and clindamycin (38.4%). Prevotella showed resistance to penicillin G (69.2%), erythromycin (30.7%), metronidazole (15.3%) and clindamycin (7.6%). Porphyromonas, Peptostreptococcus, and Bifidobacterium showed susceptibility to all the drugs tested. Fusobacterium showed resistance to penicillin G (63.6%), metronidazole (54.5%), ciprofloxacin (36.3%) and erythromycin (27.2%). Peptococcus showed resistance only to ciprofloxacin (33.3%). As the anaerobic bacteria play a significant role in critical infections, all the preliminary laboratory measures are to be taken for their isolation such as proper sample collection, using appropriate media for their growth, and system for anaerobiosis. Their sensitivity pattern has to be studied as there are several reports of the emergence of resistance to various antibiotics. This antibiogram pattern helps the clinician to treat these infections with appropriate & effective therapy resulting in excellent clinical outcomes.

abscess, obligate anaerobes, antibiotic susceptibility testing, antimicrobial resistanc