Prior Antimicrobial Use Research Articles

Clostridium Difficile-Associated Diarrhea and Colitis

To review and summarize the status of diagnosis, epidemiology, infection control, and treatment of Clostridium difficile-associated disease (CDAD). A case definition of CDAD should include the presence of symptoms (usually diarrhea) and at least one of the following positive tests: endoscopy revealing pseudomembranes, stool cytotoxicity test for toxin B, stool enzyme immunoassay for toxin A or B, or stool culture for C difficile (preferably with confirmation of organism toxicity if a direct stool toxin test is negative or not done). Testing of asymptomatic patients, including those who are asymptomatic after treatment, is not recommended other than for epidemiologic purposes. Lower gastrointestinal endoscopy is the only diagnostic test for pseudomembranous colitis, but it is expensive, invasive, and insensitive (51% to 55%) for the diagnosis of CDAD. Stool culture is the most sensitive laboratory test currently in clinical use, but it is not as specific as the cell cytotoxicity assay. C difficile is the most frequently identified cause of nosocomial diarrhea. The majority of C difficile infections are acquired nosocomially, and most patients remain asymptomatic following acquisition. Antimicrobial exposure is the greatest risk factor for patients, especially clindamycin, cephalosporins, and penicillins, although virtually every antimicrobial has been implicated. Cases of CDAD unassociated with prior antimicrobial or antineoplastic use are very rare. Hands of personnel, as well as a variety of environmental sites within institutions, have been found to be contaminated with C difficile, which can persist as spores for many months. Contaminated commodes, bathing tubs, and electronic thermometers have been implicated as sources of C difficile. Symptomatic and asymptomatic infected patients are the major reservoirs and sources for environmental contamination. Both genotypic and phenotypic typing systems for C difficile are available and have enhanced epidemiologic investigation greatly. Successful infection control measures designed to prevent horizontal transmission include the use of gloves in handling body substances and replacement of electronic thermometers with disposable devices. Isolation, cohorting, handwashing, environmental disinfection, and treatment of asymptomatic carriers are recommended practices for which convincing data of efficacy are not available. The most successful control measure directed at reduction in symptomatic disease has been antimicrobial restriction. Treatment of symptomatic (but not asymptomatic) patients with metronidazole or vancomycin for 10 days is effective; metronidazole may be preferred to reduce risk of vancomycin resistance among other organisms in hospitals. Recurrence of symptoms occurs in 7% to 20% of patients and is due to both relapse and reinfection. Over 90% of first recurrences can be treated successfully in the same manner as initial cases. Combination treatment with vancomycin plus rifampin or the addition orally of the yeast Saccharomyces boulardii to vancomycin or metronidazole treatment has been shown to prevent subsequent diarrhea in patients with recurrent disease.

Laboratory diagnosis of Haemophilus ducreyi: Sensitivity of culture media

Laboratory confirmation of the clinical diagnosis of chancroid requires the isolation of Haemophilus ducreyi . Enriched gonococcal (GcHbS) and Mueller-Hinton agar (MHHb) both support the growth of most strains of H. ducreyi . In this study we compared the isolation rate of H. ducreyi on McHbs and MHHb media in 111 men with genital ulcer disease. A second culture was obtained in 84 men at 48 hr in order to determine the reproducibility of H. ducreyi culture. The sensitivity of a single and a sequential pair of cultures on GcHbS was 67% and 74%, respectively, on men with presumed chancroid. The sensitivity of the MHHb as a single culture was 53%. Using both media for the initial culture of genital ulcers, and repeating the culture on GcHbs at 48 hr, increased the sensitivity of the isolation of H. ducreyi to 92% in men who had no prior antimicrobial use and who had no laboratory evidence of primary syphilis.

Clostridium difficile

• We examined 45 (80%) of 56 consecutive adult patients with malignant hematologic disorders who were hospitalized during a 15-week period at Emory University Hospital, Atlanta. Stool samples for<i>Clostridium difficile</i>culture and cytotoxin assay were obtained on admission and then weekly during each patient's hospitalization. On admission, four patients had detectable<i>C difficile</i>in their stool samples, which was associated with prior antimicrobial use but not with prior cancer chemotherapy. One of the four patients with positive stool samples also had toxin present in the stool sample and was the only one with diarrhea. Eight (36%) of 22 patients hospitalized for one or more weeks had<i>C difficile</i>isolated from at least one stool specimen. The positive cultures showed no clustering in time, and no risk factors were identified for colonization. Only seven of 15 culture-positive stool samples and three of seven toxin-positive samples were associated with diarrhea. (<i>Arch Intern Med</i>1984;144:967-969)

Clostridium difficile. Colonization and toxin production in a cohort of patients with malignant hematologic disorders.

We examined 45 (80%) of 56 consecutive adult patients with malignant hematologic disorders who were hospitalized during a 15-week period at Emory University Hospital, Atlanta. Stool samples for Clostridium difficile culture and cytotoxin assay were obtained on admission and then weekly during each patient's hospitalization. On admission, four patients had detectable C difficile in their stool samples, which was associated with prior antimicrobial use but not with prior cancer chemotherapy. One of the four patients with positive stool samples also had toxin present in the stool sample and was the only one with diarrhea. Eight (36%) of 22 patients hospitalized for one or more weeks had C difficile isolated from at least one stool specimen. The positive cultures showed no clustering in time, and no risk factors were identified for colonization. Only seven of 15 culture-positive stool samples and three of seven toxin-positive samples were associated with diarrhea.