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Frequency of isolation of anaerobic bacteria from surgical infections and their antimicrobial resistance pattern

Abstract number: P2064

Giannopoulou P., Kyratsa A., Grafakos I., Zambou A., Salem Z., Zafiropoulou A., Trikka-Graphakos E.

Objectives: To estimate the frequency of anaerobic bacteria and their susceptibility pattern during an 18 month period(2006–2007).

Methods: 1760 specimens were studied retrospectively from intraabdominal wounds, diabetic foot ulcers, soft tissue, bone and joint infections, intrapelvic abscesses, peritoneal fluid infections, burns and other infectious sites. All samples were cultured according to conventional methods in aerobic and anaerobic conditions. Antibiotic susceptibility testing was performed by E-test(AB Biodisk, Sweden).

Results: 167(7.3%)anaerobic bacteria were isolated from 129 anaerobic cultures. 27 anaerobic cultures were polymicrobial. 42(25.1%) strains of Gram(+) anaerobic bacteria were isolated (22 Clostridium spp., 13 Peptostreptococcus spp., 4 Eubacterium spp., 3 Propionibacterium acnes) and 125(74.8%) strains of Gram(-) anaerobic bacteria (57 Bacteroides fragilis, 36 Bacteroides non-fragilis group, 20 Prevotella spp., 4 Fusobacterium spp., 4 Veillonella spp., 4 Porphyromonas spp.). 50 strains were isolated from soft tissue infections, 31 from intraabdominal wounds, 25 from peritoneal fluid infections, 24 from intrapelvic abscesses, 9 from diabetic foot, 9 from bone and joint infections, 8 from burns and 11 from other sites. Susceptibility testing was performed to metronidazole, penicillin, piperacillin-tazobactam, imipenem, cefoxitin, ceftriaxone, clindamycin, tetracycline and erythromycin. All isolates were susceptible to imipenem and piperacillin-tazobactam. Resistance to metronidazole was found in 4 isolates (Prevotella spp., Porphyromonas spp.). Bacteroides spp. isolates showed high sensitivity to b-lactamase inhibitors, metronidazole, imipenem and high resistance to clindamycin, tetracycline and erythromycin.

Conclusions: (1) Frequency of isolation of anaerobic bacteria in surgical infections was 7.3% with most common pathogen: Bacteroides spp. (mainly B. fragilis), followed by Clostridium and Prevotella spp. (2) Penicillin remains the drug of choice for clostridial infections, with metronidazole and imipenem as alternatives. High resistance to clindamycin, tetracycline and erythromycin was observed. Resistance of Gram(-) anaerobic bacteria to imipenem and metronidazole is an emerging problem.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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