Bacterial Profile and Antimicrobial Resistance to Commonly Used Antimicrobials in Intra-Abdominal Infections in Two Teaching Hospitals

Abstract

Problem statement: Intra-abdominal infections are associated with significant morbidity and mortality. The resulting infection is typically polymicrobial and comprised of both aerobic and anaerobic microbes, which need systemic antimicrobial therapy. Since the bacteriology and antimicrobial susceptibility of postoperative intra abdominal infections were not determined in Iran, so this study was performed to evaluate the antimicrobial susceptibility patterns among aerobic bacteria isolated from post-operative intra-abdominal selected samples in 2 teaching hospitals in Kerman, Iran. Approach: the peritoneal sample of 174 patients which undergone abdominal surgery were cultured by routine microbiological methods for aerobic microorganisms. Antimicrobial susceptibility testing was performed to 4 commonly used antibacterials (Ampicillin, Cefazolin, Gentamicin and Ciprofloxacin) using disc diffusion method according to the NCCLS guidelines. Results: Escherichia coli (E. coli) was the most frequent microorganism which was isolated from 70.6% of peritoneal cultures, followed by Klebsiella pneumonia (13.7%), Pseudomonas aeruginosa (10.8%) and Proteus mirabilis (4.9%). E. coli which was the most common isolate was highly susceptible to ciprofloxacin (84.6%) and gentamicin (76.9%).The resistance rate of E. coli isolates to ampicillin was very high, i.e, 80.8% of E. coli isolates were resistant to ampicillin. The resistance rate for pseudomonas and Klebsiella spp. to commonly used antimicrobials varied from 25% to ciprofloxacin to 100% to ampicillin. Conclusion: E. coli was the most common isolate in post-operative peritoneal cultures. The results showed the relatively high resistance rate of the isolated microorganisms to commonly used antimicrobials, especially to ampicillin. So the choice of antimicrobial therapy must be based on the susceptibility tests and also take into account the risk of inadequate and in appropriate antimicrobial therapy and emergence of bacterial resistance to commonly used antimicrobials.