Frequency of antibiotic-associated diarrhoea in 2462 antibiotic-treated hospitalized patients: a prospective study

The frequency of antibiotic-associated diarrhoea (AAD) and Clostridium diff icile-associated diarrhoea (CdAD) was prospectively determined in a populat ion of 2462 patients recruited from five Swedish hospitals, including divis ions for infectious diseases, orthopaedics, surgery, geriatrics, nephrology and internal medicine. AAD developed in 4.9% of the treated patients. Faec al samples were obtained from 69% of patients with AAD and 55.4% were posit ive for C. difficile cytotoxin B. The frequency of AAD varied from 1.8 to 6 .9% at the participating centres (P < 0.001). The frequency of AAD also var ied considerably between medical disciplines and wards within different hos pitals and was highest in the nephrology and geriatric units (6.7 and 7.1%, respectively). There was no difference in frequency of AAD when analysed w ith respect to gender or age. Medical interventions (laxative treatment, en doscopy and abdominal surgery) or presence of one concomitant disease (diab etes, malignancy, chronic renal disease and inflammatory bowel disease) did not significantly affect the frequency of AAD, whereas patients suffering from two or more of these illnesses had significantly (P = 0.001) higher fr equencies of AAD. Patients treated with antibiotics for <less than or equal to>3 days had a significantly (P = 0.009) lower frequency of AAD than thos e treated for longer periods. Treatment with cephalosporins, clindamycin or broad-spectrum penicillins was associated with an increased risk of AAD. W ith specimens from one centre, 62.5% of tested patients with AAD and 33.8% of asymptomatic patients were positive for cytotoxin B. Although C. diffici le cytotoxin B in stool samples was significantly associated with AAD IP = 0.003), the causal relationship with diarrhoea is not always evident.