Bacteriology and changes in antibiotic susceptibility in adults with community-acquired perforated appendicitis

Abstract

This study evaluated bacterial etiology and antibiotic susceptibility in patients diagnosed with community-acquired perforated appendicitis over a 12-year-period. We retrospectively reviewed records of adult patients diagnosed with perforated appendicitis at an 800-bed teaching hospital between January 2000 and December 2011. In total, 415 culture-positive perforated appendicitis cases were analyzed. Escherichia coli was the most common pathogen (277/415, 66.7%), followed by Streptococcus species (61/415, 14.7%). The susceptibility of E. coli to ampicillin, piperacillin/tazobactam, ceftriaxone, cefepime, amikacin, gentamicin, and imipenem was 35.1%, 97.1%, 97.0%, 98.2%, 98.9%, 81.8%, and 100%, respectively. The overall susceptibility of E. coli to quinolones (ciprofloxacin or levofloxacin) was 78.7%. During the study period, univariate logistic regression analysis showed a significant decrease in E. coli susceptibility to quinolones (OR = 0.91, 95% CI 0.84-0.99, P = 0.040). We therefore do not recommend quinolones as empirical therapy for community-acquired perforated appendicitis.

Figure 1. Change of antimicrobial susceptibility among E. coli during the 12-year-period.

AMP, ampicillin; AZT, aztreonam; TZP, piperacillin/tazobactam; CFZ, cefazolin; FOX, cefoxitin; CRO, ceftriaxone; FEP, cefepime; QUI, quinolone; TMX, trimethoprim/sulfamethoxazole; AMK, amikacin; GM, gentamicin; TOB, tobramycin; IPM, imipenem. * During the study period, there was a significant decrease in antimicrobial susceptibility on univariate logistic regression analysis (P = 0.040).