An outbreak of acute gastroenteritis (AGE) occurred in a 201-bed geriatric convalescent facility in Los Angeles County during December 1988 through January 1989. The attack rate was 55% among residents and 25% among employees. Illnesses were characterized by vomiting and diarrhea to a lesser extent, and the absence of fever. Bacterial and parasitic tests in a sample of patients were negative. A 27nm small round structured virus (SRSV) was identified in one of 30 stools studied by immune electron microscopy (IEM). While rotavirus and influenza A and B were found in three, one and three cases, respectively, no alternative etiologic agent could be demonstrated for most cases. The outbreak met Centers for Disease Control (CDC) clinical and epidemiologic criteria for Norwalk-like gastroenteritis. The death rate of residents was not elevated beyond baseline during the outbreak; however, one healthy employee had diarrhea and dehydration and died after developing an arrhythmia. An autopsy showed moderate, diffuse lymphocytic and neutrophilic myocarditis, and viral studies found influenza A in left ventricular tissue. Fourteen (25%) of 57 employee cases worked in occupations without routine stool or patient contact. At least nine of these employees lacked evidence of direct fecal contact, and transmission of infection in these cases may have been airborne. (Infect Control Hosp Epidemiol. 1990;11:459-464.)

The impact of recently recommended hospital infection control guidelines on Canadian acute-care hospitals is unknown. A confidential cross-sectional mailed survey of all acute-care Canadian hospitals was conducted to determine rates of receipt and adoption of published guidelines for Universal Precautions (UP) or Body Substance Isolation (BSI), rationale for adoption and knowledge of costs and benefits. Five hundred and seventy-nine of 943 sites (61%) responded (exceeding 80% in urban centers); 94% among hospitals with at least 300 beds and 57% among those under 300 beds. Seventy-four percent of responders claimed adoption of UP (65%) or BSI (9%), staff protection being their primary motivation. Adoption of either UP or BSI was associated with size (p<.001), increasing progressively from 45% in the smallest group (~25 beds) to 64% in the largest (2500 beds). Many hospitals introduced modifications and some substituted names other than UP or BSI in adopting a new strategy. In practice, UP and BSI now mean different things in different hospitals, and the distinction between them has become blurred. Furthermore, only 5% claiming adoption of a new strategy adopted all of the fundamental policies expected under UP or BSI. Receipt of guidelines was also correlated with size: one-third of hospitals under 200 beds had not received key publications defining UP and BSI. Only 19% claiming adoption of a new strategy indicated knowledge of cost implications. These results suggest a need for closer collaboration among hospitals and government agencies in developing uniform infection control policies, and for systematic evaluation of the cost and effectiveness of new strategies. (Infect Control Hosp Epidemiol. 1990;11:465-472.)

During the 1984–1985 influenza season, outbreaks of influenza A (H3N2) occurred in three Connecticut nursing homes. Influenza vaccination rates were 67% (96 out of 144), 35% (30 out of 85) and 69% (332 out of 483), respectively. The relative risk of illness for vaccinated compared to unvaccinated residents was 1.8 (95% confidence interval, 0.6, 5.9), 1.6 (95% confidence interval, 0.8, 3.0) and 1.1 (95% confidence interval, 0.8, 1.7) for each of the three nursing homes, respectively. In the third outbreak, 22 vaccinated residents without clinical illness had a geometric mean titer of hemagglutination-inhibition (HI) antibody of 20. Although low, this titer was significantly higher than that of nine unvaccinated residents without clinical illness (12, p<.05); only three (14%) vaccinated residents had HI titers of 340. These results suggest that levels of HI antibody in vaccinated residents were not protective at the time of the third outbreak, four to five months after vaccination. In general, the study of vaccine effectiveness in nursing homes is limited by sample size and statistical power. Despite these limits, the retrospective investigation of influenza outbreaks in nursing homes is often the only practical way to evaluate influenza vaccine effectiveness in the elderly on a yearly basis.

Methicillin-resistant Staphylococcus aureus (MRSA) has been an endemic nosocomial pathogen at the VA medical center (VAMC) in Providence, Rhode Island since 1981. From 1985 to 1987, more than 30% of all unique S aureus isolates were methicillin resistant. To evaluate the frequency of acquisition of MRSA isolates by healthcare workers, we compared the antimicrobial susceptibility patterns, multilocus enzyme genotypes and plasmid profiles of isolates recovered from nasal and hand cultures from VAMC nurses and house staff on rotation at the VAMC with those of clinical isolates from patients at the VAMC and four other affiliated hospitals. Fifty-six percent of ward nurses cultured (n = 112) were colonized with S aureus, of which 65% was methicillin resistant. Six isolates of MRSA were identified on the initial culturing of house staff (n=65); 16 MRSA isolates were recovered at the end of a four-week rotation (p<.02). Phenotypic and genotypic analyses demonstrated that numerous distinct MRSA strains were recovered in the study period. The incidence of MRSA among clinical isolates at the VAMC and affiliated institutions was remarkably constant throughout the three-year study period. Moreover, despite regularly sharing resident physicians, interns and medical students, MRSA isolates were uncommonly recovered at the other university-affiliated hospitals. Our study failed to reveal evidence of significant interhospital transmission of MRSA isolates by healthcare workers. While healthcare workers may contribute to the dissemination of MRSA within institutions, they appear to be less important in spreading MRSA between institutions (Infect Control Hosp Epidemiol. 1990;11:479-485.).

Aztreonam, the first licensed monobactam in the United States, is a β-lactam antimicrobial agent with a unique structure and in vitro spectrum of activity. The drug is active only against gram-negative aerobic bacteria in vitro, thus resembling the spectrum of aminoglycosides, but displays the safety profile typical of β-lactam agents. Due to these properties, aztreonam may prove useful in the therapy of various nosocomial infections. This review outlines the salient features of aztreonam and suggests areas of appropriate usage.

Strongyloides stercoralis is a common nematode causing helminthic infections in humans. Strongyloidiasis is principally distributed in the tropics and subtropics. In the United States, a prevalence of 0.4% to 4% has been estimated in southeastern states. Like many other parasitic infections, strongyloidiasis most often is asymptomatic unless the patient becomes immunosuppressed. Immunosuppression can lead to an overwhelming autoinfection, which is highly fatal. This hyperinfection often occurs in hospitalized patients and may be confused with other nosocomial infections. This report will review the salient aspects of strongyloidiasis.