Antibiotic prophylaxis and the risk of Clostridium difficile-associated diarrhoea

To test the hypothesis that extended antibiotic prophylaxis increases the r isk of Clostridium difficile-associated diarrhoea (CDAD), we conducted a re trospective cohort study of 2641 patients under-going cardiovascular surger y. Main outcome measures were the duration of prophylaxis (<48 h vs. > 48 h ) and the occurrence of CDAD. CDAD occurred in 31 patients (1.2%), who were significantly older (70+/-9 y vs. 66+/-10 y; P=0.03), received more therap eutic antibiotics (2.2+/-1.9 vs. 0.4+/-0.9; P<0.001) and had a longer posto perative hospital stay (26+/-19 d vs. 9+/-8 d; P < 0.001) than non-cases. A fter adjusting for confounding, we did not observe an association between p rolonged prophylaxis and CDAD [adjusted odds ratio (AOR), 0.8; CI, 0.4-1.8] . In contrast, three independent predictors were identified: increasing len gth of hospital stay (AOR per one-day-increment, 1.03; CI, 1.01-1.05), and treatment with third generation cephalosporins (AOR, 5.9; CI, 2.2-16.0) or beta -lactam-beta -lactamase inhibitor combinations (AOR, 4.6; CI, 1.7-12.3 ). Our results did not confirm that extended prophylaxis after clean surger y increases the risk of CDAD, which remains an uncommon postoperative compl ication, associated even with short antibiotic exposure. (C) 2001 The Hospi tal Infection Society.