Patients in two acute care university hospitals were entered into the study using the following method: twenty patients were selected each day from all floors/units in each hospital until the hospital communities had been surveyed only once. A total of 762 hospital patients were identified for the study, and the history of each patient was then abstracted from their charts. The data were analyzed as an historical cohort study design. The two hospital samples were compared to show the effects of the non-random sampling method using one hospital as a comparison group for the other. Expected associations between nosocomial infection and known risk factors were compared and contrasted between the hospitals using cumulative incidence rates and relative risk ratios. The average length of stay of the group of patients in each hospital was extended from a mean of ten days to a mean of 30 days. The only significant difference between the two hospital cohorts was an age effect. The advantages and disadvantages of this method for selecting a long staying cohort at high risk for nosocomial infection in acute care facilities are detailed.

Subcutaneous abscesses occurred at hip and deltoid injection sites in 13 student nurse assistants following practice injections. Mycobacterium chelonei was isolated from three cases and was the presumptive pathogen in other temporally clustered cases with similar clinical findings. A 1,000 cc bottle of 0.9 N saline used as a source for practice injection solution was the apparent source of the organism.

Presenting findings included tenderness (7), swelling (7), fever (3), adenopathy (1) and weight loss (1). All cases were characterized by long incubation periods (6 to 16 weeks) and delayed resolution (mean 8.8 months), and required surgical drainage or wedge excision for therapy. Antituberculous therapy was administered in three cases. Complications were limited to scarring in seven cases with keloid formation in two and persistent pain in three cases. This outbreak reinforces the importance of penetrating trauma in this cutaneous mycobacterial infection and emphasizes the emergence of this organism as an important nosocomial pathogen.

Review of necropsy reports for evidence of undiagnosed antemortem infection is included by the Joint Commission on Accreditation of Hospitals as an element of an effective hospital infection control program. We reviewed records of 155 patients autopsied at St. Paul-Ramsey Medical Center between January 1, 1980 and March 31, 1981. In 13 patients (8%), there was a discrepancy between documentation of infection during the patient's hospitalization and at autopsy. However, in none of these cases was this information useful in our infection control program. We doubt the effectiveness of necropsy review as a tool for nosocomial infection control.

Environmental transmission of Clostridium difficile, the causative agent of antibiotic-associated pseudomembranous colitis (PMC), has been supported by animal studies and implicated in spread of C. difficile among leukemic children receiving non-absorbable antibiotics. We report antibiotic-associated C. difficile-related colitis in two adults who shared a commode chair during hospitalization.