Anaerobic bacteria and bacterial infections: perspectives on treatment and resistance in Italy.

Results of laboratory tests of 2,000 samples obtained from 1984 to 1987 from patients with suspected anaerobic infections and the clinical experience of these patients are reported. Of these samples, 395 were positive for anaerobes; 36.5% of these 395 samples contained single organisms, and 63.5% contained a mixture of anaerobes and aerobes. Abdominal infections were the infections most frequently caused by anaerobes. The Bacteroides fragilis group and strains of Peptostreptococcus were the microorganisms most frequently isolated. In addition, 300 anaerobes isolated from clinical samples at three Italian hospitals were tested for susceptibility to 10 antibiotics (aztreonam, cefotaxime, cefoxitin, ceftazidime, ceftriaxone, clindamycin, imipenem, metronidazole, penicillin, and piperacillin). Imipenem and metronidazole proved to be the most active agents, with low and similar values for the 50% and 90% minimal inhibitory concentrations (MICs). No microorganism showed resistance to these agents. After imipenem and metronidazole, clindamycin was the most effective agent tested. All other antibiotics tested showed elevated MICs against Bacteroides species and Clostridium difficile. In Italy, cefoxitin still maintains satisfactory activity against the majority of anaerobes tested.