To study the epidemiology of Acinetobacter baumanii during a period of increased seasonal prevalence.

Descriptive molecular and clinical epidemiologic study of A baumanii isolates from 1990 through 1992.

A 770-bed urban, acute, tertiary-care university hospital.

During 1990 through 1992, the rate of A baumanii isolations was 30.4 per 1,000 culture isolations during the summer, compared to 12.6 per 1,000 culture isolations during the fall, winter, and spring (P<.000001). There were 320 isolates identified among 260 patients during this time. Eighty-one patients with isolates available were identified for evaluation; they ranged in age from 2 months to 95 years. Pulsed-field gel electrophoresis (PFGE) typing showed that 59 (83%) of 71 typed isolates had distinct PFGE patterns. There were three small clusters of isolates with the same PFGE patterns, suggesting cross-transmission in those instances.

A seasonally increased prevalence of A baumanii largely associated with device-related nosocomial infections in severely ill patients was noted over a 3-year period. Although there were isolated instances of cross-transmission, most isolates had distinct PFGE patterns. Clonal dissemination of a single strain was not responsible for the seasonal increased prevalence of A baumanii. PFGE typing was useful in directing control efforts.

To characterize risk factors for outbreak-associated influenza illness and death in a nursing home.

Outbreak investigation with predetermined and concurrently determined risk information.

A nursing home service in a multiward chronic care hospital, Honolulu, Oahu, 1989 to 1990.

Elderly nursing home patients receiving long-term care.

Influenza vaccination, amantadine administration, and infection control measures.

Neither routine infection control measures nor vaccination prevented illness, complications, or death in a nursing home outbreak of influenza A. The 55% case-fatality rate resulted from severe pneumonia. Influenza transmission may have been mediated by staff via either contaminated hands or fomites.

Data from this and other outbreaks suggest that recommendations for preventing nosocomial influenza in the nation’s 1.5 million nursing home residents should be reconsidered.

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.

To evaluate the impact of a coordinated approach for the isolation, diagnosis, and treatment of patients with tuberculosis.

Retrospective cohort study.

Bronx-Lebanon Hospital Center, an inner-city hospital in the South Bronx, New York City.

Patients with smear-positive, culture-confirmed pulmonary tuberculosis.

Institution of a coordinated tuberculosis team.

Admissions of 46 patients before and 39 patients after the formation of a tuberculosis team were reviewed. Before institution of the tuberculosis team, 35% of patients were isolated within 24 hours of presentation, 41% never were isolated, and the mean number of days patients were not isolated was 19. After implementation of the tuberculosis team, 59% of patients were isolated within 24 hours, only 5% were never isolated, and the mean number of days patients were not isolated was 3.5. These differences were statistically significant. There also was a corresponding decrease in length of hospitalization. In addition, there were noticeable improvements in patient and staff morale and attitudes.

The tuberculosis team likely has decreased the risk of nosocomial tuberculosis transmission by increasing the proportion of infectious tuberculosis patients admitted into AFB isolation and by reducing (by 780) the number of days out of isolation while smear positive. There also were concomitant financial savings.

DNA amplification by the polymerase chain reaction (PCR) of human cytomegalovirus (CMV) nucleotide sequences recently has been reported for differentiation of CMV strains.

Retrospective study.

Evaluate the strain patterns of 15 CMV-positive buffy coat specimens from five pediatric bone marrow transplant patients.

Pediatric bone marrow transplant unit.

We performed PCR using primers corresponding to two distinct regions of the CMV genome, the major immediate-early (MIE) region and the a-sequence region, with subsequent restriction enzyme analysis of the amplified products.

Restriction enzyme analysis with Hae III and Hinf I of products amplified with nested PCR for the MIE region revealed distinguishable digestion patterns between patients but similar patterns for samples from each patient. All were distinct from the CMV Towne laboratory control strain. In contrast to these results, amplification of specimens with a-sequence primers, followed by restriction enzyme analysis, did not allow differentiation between all patients.

Our results indicate that nested amplification directly from buffy coat specimens using primers for the CMV MIE gene allows rapid CMV strain characterization that is useful for laboratory quality control and epidemiological studies. Distinct CMV strains were found in each patient, suggesting horizontal transmission was not responsible for acquisition of CMV infection in these patients.

To determine the prevalence of tuberculin reactivity among all new employees at a hospital in New York City.

Prospective measurement of purified protein derivative (PPD) status in consecutive new employees at a hospital in New York City from 1991 to 1993. All employees are tested as part of a pre-employment physical, assuring complete compliance. Aplisol (Parke-Davis, Morris Plains, NJ) was used in 1991 and 1992, and Tubersol (Connaught, Swiftwater, PA) in 1993. Tests were applied and interpreted by trained employee health personnel.

Of 313 consecutive new employees, comprising all job categories, 40% were PPD positive at time of initial hire, including 20% of US-born and 70% of foreign-born employees. Of 114 persons who had received BCG vaccination, 67% were PPD positive. By multivariate regression analysis, age, BCG vaccination history, and foreign country of birth were independent predictors of a reactive PPD test.

The high prevalence of tuberculin reactivity may reflect high rates of Mycobacterium tuberculosis infection and disease in the community, complicating interpretation of the efficacy of Centers for Disease Control and Prevention (CDC) guidelines to prevent the spread of tuberculosis in healthcare facilities.

To determine if an attachable silver-impregnated cuff is effective in reducing subclavian hemodialysis catheter-related infections.

Prospective, randomized, nonblinded study.

Community teaching hospital.

One hundred one acute and chronic renal failure patients requiring subclavian venipuncture and catheterization. After randomization, 47 patients underwent subclavian catheterization with a silver-impregnated cuff (Ag-CC), and 54 patients had routine catheter (RC) placements.

Multiple presumed predictor variables for catheter-related infections, exit site infection rate, bacteremia rates, and semiquantitative cultures of all catheters.

There were no significant differences between the AG-CC and the RC groups for catheter colonization, exit site infection, catheter sepsis, any catheter-related infections, or the incidence of infections within the first 7 or 14 days. Although the differences did not achieve statistical significance, the RC group was more likely to experience catheter colonization (20.4% versus 14.9%) and exit site infection (5.6% versus 2.1%). However, the RC group contained nearly twice as many intensive care (ICU) patients (44% versus 23%; P=.027), and ICU subjects were twice as likely to acquire catheter infection (P<.002).

Although the sample size was insufficient to exclude Type 2 errors, it appears that the attachable silver-impregnated cuff did not reduce subclavian catheter-related infections in our patient population.