ETIOLOGIC AGENTS OF INFECTIOUS DIARRHEA - IMPLICATIONS FOR REQUESTS FOR MICROBIAL CULTURE

Gastrointestinal infections remain a frequent disease worldwide, In or der to increase our knowledge of the epidemiology for our patient popu lation, we retrospectively analyzed the results obtained for stool sam ples received at the clinical microbiology laboratory of the Universit y Hospital of Geneva during a 4-year period, A total of 13,965 specime ns from 7,124 patients (1.96 specimens per patient) were cultured, yie lding 369 (2.6%) Salmonella spp., 408 (2.9%) Campylobacter spp., and 7 9 (0.6%) Shigella spp, The cumulative positivity rate of 6.1% decrease d to 2.7% when patients received antimicrobial agents (P < 0.001), The positivity rate for 5,912 specimens obtained from patients hospitaliz ed for less than or equal to 3 days was 12.6%, whereas it dropped to 1 .4% for patients hospitalized for >3 days (P < 0.001), Of 3,837 stool samples originating from pediatric patients, 8.8% were positive, and 5 .1% of 10,128 samples from adults were positive (P < 0.001), The cytot oxin of Clostridium difficile was detected in 379 of 3,723 samples ana lyzed (10.2%), and rotaviruses were detected in 190 of 1,601 samples ( 11.9%). We recommend that the use of cultures for enteric bacterial pa thogens be restricted to patients hospitalized for less than or equal to 3 days, with the exceptions of follow-up samples, specimens from im munocompromised patients, and patients whose first sample was culture negative or in the rare event of nosocomial food-borne outbreaks, For patients under antimicrobial therapy, testing for cytotoxin of C. diff icile should primarily be requested; this analysis should also be acce pted for samples from patients not receiving antimicrobial agents at t he time of specimen collection, By applying these restrictions, we cou ld have saved at least $5,000 annually.