New advances in the use of antimicrobial agents in surgery: intra-abdominal infections

Treatment of anaerobic infection

Anaerobic bacteria are the predominant flora in the normal human skin and mucous membranes and are, therefore, a common cause of endogenous infections. Since anaerobic infections are generally polymicrobial, where anaerobes are mixed with aerobic organisms, therapy should provide coverage of both types of pathogens. The isolation of anaerobes requires appropriate methods of collection, transportation and cultivation of specimens. The lack of use of any of these methods can lead to inadequate recovery of anaerobes and inappropriate therapy. Treatment of anaerobic infection is complicated by the slow growth of these organisms and the growing resistance of anaerobic bacteria to antimicrobials. The primary role of antimicrobials is to limit the local and systemic spread of infection. Surgical drainage is of primary importance. This includes debriding of necrotic tissue, draining the pus, improving circulation, alleviating obstruction and increasing tissue oxygenation. The most effective antimicrobials against anaerobic organisms are metronidazole, the carbapenems (imipenem, meropenem and ertapenem), chloramphenicol, the combinations of a penicillin and a beta-lactamase inhibitor (ampicillin or ticarcillin plus clavulanate, amoxicillin plus sulbactam, and piperacillin plus tazobactam), tigecycline and clindamycin.

Ciprofloxacin/metronidazole versus β-lactam-based treatment of intra-abdominal infections: a meta-analysis of comparative trials

Intra-abdominal infections are polymicrobial and result in substantial morbidity and mortality. The combination of ciprofloxacin/metronidazole as well as several beta-lactam-based regimens are among the commonly used regimens for the treatment of patients with such infections. Thus, we sought to review the evidence from available comparative clinical trials studying ciprofloxacin/metronidazole versus broad-spectrum beta-lactam-based regimens in the treatment of intra-abdominal infections. Studies for the meta-analysis were retrieved from searches of the PubMed database. Five available comparative trials (four randomised controlled trials and one non-randomised comparative trial) including 1431 patients with intra-abdominal infections were included in the meta-analysis. There was a statistically significant difference between the compared arms with regard to cure in favour of the ciprofloxacin/metronidazole combination (odds ratio (OR)=1.69, 95% confidence interval (CI) 1.20-2.39). There was no statistically significant difference between the compared arms with regard to total mortality (OR=1.10, 95% CI 0.71-1.69), mortality attributable to infection (OR=1.42, 95% CI 0.66-3.06) and toxicity (OR=1.25, 95% CI 0.66-2.35). In conclusion, pooled data from the available comparative trials suggest that the ciprofloxacin/metronidazole combination may be superior to beta-lactam-based therapeutic regimens in the treatment of intra-abdominal infections with regard to cure of infections, although no difference in mortality was found.