To compare mortality following isolation of influenza A to mortality following isolation of other respiratory viruses in a nursing home.

The Wisconsin Veterans Home, a 688-bed skilled nursing facility for veterans and their spouses.

All residents with respiratory viral isolates obtained between 1988 and 1999.

Thirty-day mortality was determined following each culture-proven illness.

Thirty-day mortality following isolation of viral respiratory pathogens was 4.7% (15/322) for influenza A 5.4% (7/129) for influenza B; 6.1% (3/49) for parainfluenza type 1; 0% (0/26) for parainfluenza types 2,3, and 4; 0% (0/26) for respiratory syncytial virus (RSV); and 1.6% (1/61) for rhinovirus.

Mortality following isolation of certain other respiratory viruses may be comparable to that following influenza A (although influenza A mortality might be higher without vaccination and antiviral agents). The use of uniform secretion precautions for all viral respiratory illness deserves consideration in nursing homes.

Coagulase-negative staphylococci (CNS) are the major cause of nosocomial bloodstream infection. Emergence of vancomycin resistance among CNS is a serious public health concern, because CNS usually are multidrug-resistant, and glycopeptide antibiotics, among which only vancomycin is available in the United States, are the only remaining effective therapy. In this report, we describe the first bloodstream infection in the United States associated with a Staphylococcus epidermidis strain with decreased susceptibility to vancomycin.

We reviewed the hospital's microbiology records for all CNS strains, reviewed the patient's medical and laboratory records, and obtained all available CNS isolates with decreased susceptibility to vancomycin. Blood cultures were processed and CNS isolates identified by using standard methods; antimicrobial susceptibility was determined by using minimum inhibitory concentration (MIC) and disk-diffusion methods. Nares cultures were obtained from exposed healthcare workers (HCWs) to identify possible colonization by CNS with decreased susceptibility to vancomycin.

The bloodstream infection by an S epidermidis strain with decreased susceptibility to vancomycin occurred in a 49-year-old woman with carcinoma. She had two blood cultures positive for CNS; both isolates were S epidermidis. Although susceptible to vancomycin by the disk-diffusion method (16-17 mm), the isolates were intermediate by MIC (8-6 μg/mL). The patient had received an extended course of vancomycin therapy; she died of her underlying disease. No HCW was colonized by CNS with decreased susceptibility to vancomycin.

This is the first report in the United States of bloodstream infection due to S epidermidis with decreased susceptibility to vancomycin. Contact precautions likely played a role in preventing nosocomial transmission of this strain, and disk-diffusion methods may be inadequate to detect CNS with decreased susceptibility to vancomycin.

To determine the attributable hospital stay and costs for nosocomial methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S aureus (MRSA) primary bloodstream infections (BSIs).

Pairwise-matched (1:1) nested case-control study.

University-based tertiary-care medical center.

Patients admitted between December 1993 and March 1995 were eligible. Cases were defined as patients with a primary nosocomial S aureus BSI; controls were selected according to a priori matching criteria.

Length of hospital stay and total and variable direct costs of hospitalization.

The median hospital stay attributable to primary nosocomial MSSA BSI was 4 days, compared with 12 days for MRSA (P=.023). Attributable median total cost for MSSA primary nosocomial BSIs was $9,661 versus $27,083 for MRSA nosocomial infections (P=.043).

Nosocomial primary BSI due to S aureus significantly prolongs the hospital stay. Primary nosocomial BSIs due to MRSA result in an approximate threefold increase in direct cost, compared with those due to MSSA.

To describe a pseudoepidemic of infectious scleritis following eye surgery.

Retrospective cohort study with selected procedural and laboratory investigations.

Twenty-one patients with postoperative scleritis were identified during a 2-month outbreak. Neither an infectious etiology nor a causative pre-, intra-, or postoperative exposure was found. The clinical findings, when carefully reviewed, were consistent with poor surgical-wound closure.

The art of clinical diagnosis involves the subjective interpretation of clinical history, physical findings, and laboratory results. A repeated error in the interpretation of clinical findings can simulate an outbreak of disease. Clinicians may be reluctant to concede misdiagnosis

To determine the cause and mode of transmission of a cluster of infections due to Enterobacter cloacae.

Retrospective cohort study in a neonatal intensive-care unit (NICU) from December 1996 to January 1997; environmental and laboratory investigations.

60 infants hospitalized in the NICU during the outbreak period.

Odds ratios (OR) linking E cloacae colonization or infection and various exposures. All available E cloacae isolates were typed and characterized by contour-clamped homogenous electric-field electrophoresis to confirm possible cross-transmission.

Of eight case-patients, two had bacteremia; one, pneumonia; one, soft-tissue infection; and four, respiratory colonization. Infants weighing <2,000 g and born before week 33 of gestation were more likely to become cases (P<.001). Multivariate analysis indicated that the use of multidose vials was independently associated with E cloacae carriage (OR, 16.3; 95% confidence interval [CI95], 1.8-∞ P=011). Molecular studies demonstrated three epidemic clones. Cross-transmission was facilitated by understaffing and overcrowding (up to 25 neonates in a unit designed for 15), with an increased risk of E cloacae carriage during the outbreak compared to periods without understaffing and overcrowding (relative risk, 5.97; CI95, 2.2-16.4). Concurrent observation of healthcare worker (HCW) handwashing practices indicated poor compliance. The outbreak was terminated after decrease of work load, increase of hand antisepsis, and reinforcement of single-dose medication.

Several factors caused and aggravated this outbreak: (1) introduction of E cloacae into the NICU, likely by two previously colonized infants; (2) further transmission by HCWs' hands, facilitated by substantial overcrowding and understaffing in the unit; (3) possible contamination of multidose vials with E cloacae. Overcrowding and understaffing in periods of increased work load may result in outbreaks of nosocomial infections and should be avoided.

To investigate relationships between the incidence of methicillin-resistant Staphylococcus aureus (MRSA) and the use of different classes of antimicrobials in Belgian hospitals.

Using Pearson correlation coefficients, the number of new nosocomial MRSA-colonized or -infected patients in the second half of 1994 and the first half of 1995 reported by the national MRSA surveillance program was compared with use of various antimicrobial classes as reported by the National Institute for Sickness and Disability Insurance. Relationships between different classes of antimicrobials were evaluated in a correlation matrix. MRSA incidence, antimicrobial use, and potential confounding factors were included in a multiple linear regression analysis.

50 hospitals in Belgium.

The use of a number of different classes of antimicrobials was interrelated. In the multivariate analysis, the incidence of nosocomial MRSA increased with increasing use of ceftazidime and cefsulodin (P=.0003), amoxicillin with clavulanic acid (P=.02), and quinolones (P=.005). No association was found between MRSA incidence and total antimicrobial use.

The relationships between antimicrobial use and MRSA are complex. Interventions aimed at promoting more rational prescribing patterns should be supported by adequate experimental and epidemiological evidence. Advice for preventing and controlling MRSA has focused mainly on hygienic measures and precautions to avoid cross-transmission; the role of relieving antimicrobial pressure needs to be clarified.

To assess possible transmission modes of, and risk factors for, gastroenteritis associated with Norwalk-like viruses (NLVs) in a geriatric long-term-care facility.

During a prolonged outbreak of acute gastroenteritis, epidemiological data on illness among residents and employees were collected in conjunction with stool, vomitus, and environmental specimens for viral testing. NLVs were identified by electron microscopy in stool and vomitus specimens, and further characterized by reverse-transcriptase polymerase chain reaction and nucleotide sequencing. Potential risk factors were examined through medical-record review, personal interview, and a self-administered questionnaire sent to all employees.

During the outbreak period, 52 (57%) of 91 residents and 34 (35%) of 90 employees developed acute gastroenteritis. Four case-residents were hospitalized; three residents died at the facility shortly after onset of illness. A point source was not identified; no association between food or water consumption and gastroenteritis was identified. A single NLV strain genetically related to Toronto virus was the only pathogen identified. Residents were at significantly higher risk of gastroenteritis if they were physically debilitated (relative risk [RR], 3.5; 95% confidence interval [CI95], 1.0-12.9), as were employees exposed to residents with acute gastroenteritis (RR, 2.6; CI95, 1.1-6.5) or ill household members (RR, 2.3; CI95, 1.4-3.6). Adherence to infection control measures among the nursing staff may have reduced the risk of gastroenteritis, but the reduction did not reach statistical significance.

In the absence of evidence for food-borne or waterborne transmission, NLVs likely spread among residents and employees of a long-term-care facility through person-to-person or airborne droplet transmission. Rapid notification of local health officials, collection of clinical specimens, and institution of infection control measures are necessary if viral gastroenteritis transmission is to be limited in institutional settings

To determine the cost-effectiveness of a policy of screening high-risk patients for methicillin-resistant Staphylococcus aureus (MRSA) colonization on admission to hospital.

980-bed university-affiliated tertiary-care hospital.

Between June 1996 and May 1997, patients directly transferred from another hospital or nursing home, or who had been hospitalized in the previous 3 months, were screened for MRSA within 72 hours of hospital admission.

Nasal, perineal, and wound swabs were obtained for MRSA screening using standard laboratory methods. Laboratory and nursing costs associated with screening patients for MRSA on admission to hospital were calculated. The costs associated with the implementation of recommended infection control measures for patients with MRSA also were determined.

3,673 specimens were obtained from 1,743 patients. MRSA was found on admission in 23 patients (1.3%), representing 36% of the 64 patients with MRSA identified in the hospital during the year. MRSA-colonized patients were more likely to have been transferred from a nursing home (odds ratio [OR], 6.4; P=.04) or to have had a previous history of MRSA colonization (OR, 13.1; P=.05). Laboratory and nursing costs were found to be $8.34 per specimen, for a total cost of $30,632 during the year. The average cost of implementing recommended infection control measures for patients colonized with MRSA was approximately $5,235 per patient.

If early identification of MRSA in colonized patients prevents nosocomial transmission of the organism to as few as six new patients, the screening program would save money.

To help define the scope of nosocomial legionnaire's disease (LD) and to assess use of recommended diagnostic methods and transmission control practices.

We surveyed 253 hospitals participating in the National Nosocomial Infections Surveillance (NNIS) System. The anonymous survey included questions about episodes of nosocomial LD, environmental sampling practices, maintenance of hospital water systems, and diagnostic techniques.

Of 192 hospitals that responded, 29% reported at least one episode of nosocomial ID from 1990 through 1996, and 61% of these reported at least two episodes. Of 79 hospitals with transplant programs, 42% reported nosocomial LD, compared with 20% of hospitals without transplant programs. Environmental sampling had been conducted by 55% of hospitals, including 79% of those reporting nosocomial LD. Legionella were isolated in 34% that sampled potable water and 19% that sampled cooling system reservoirs. Supplemental potable-water decontamination systems were installed in 20% of hospitals. Only 19% routinely performed testing for legionellosis among patients at high risk for nosocomial LD.

Nosocomial LD is relatively common among NNIS hospitals, especially those performing organ transplants. Environmental sampling for Legionella is a common practice among NNIS hospitals, and Legionella often are isolated from sampled hospital cooling towers and hospital potable-water systems. Hospitals have responded to suspected nosocomial LD infection with a variety of water sampling and control strategies; some have not attempted to sample or decontaminate water systems despite identified transmission.

To determine, among patients undergoing continuous ambulatory peritoneal dialysis (CAPD) who were Staphylococcus aureus nasal carriers, if periodic brief “pulses” of nasal mupirocin calcium ointment 2% after completion of a mupirocin eradication protocol would maintain these patients free of carriage.

Noncomparative, nonblinded study with historical controls.

A county medical center.

Patients in a CAPD program during the period April 1996 to May 1998.

All patients in the CAPD program had monthly nasal cultures for S aureus. After informed consent, S aureus nasal carriers were administered mupirocin to the nares twice a day for 5 days followed by nasal mupirocin twice monthly. Peritonitis and exit-site infection rates were monitored independently by CAPD nursing staff. Patients were monitored monthly for adverse effects of mupirocin and compliance with the maintenance regimen.

Twenty-four patients in the CAPD program were enrolled in the study and had a median duration of follow-up of 8.5 months. Fifteen (63%) of the 24 patients remained free of nasal carriage on follow-up cultures. Of the 9 patients with positive nasal cultures during the study, 8 had only one positive culture. There was no significant difference in the mean yearly peritonitis rate or S aureus peritonitis rate (January 1995-May 1998). However, there was a significant decrease in the mean yearly exit-site infection rates both overall (from 8.8 episodes per 100 patients dialyzed per month in 1995 to 4.0 in 1998; P=.008) and due to S aureus (from 5.6 in 1995 to 0.9 in 1998; P=.03). Adverse effects of nasal mupirocin were mild overall; 1 patient was removed from the study due to an allergic reaction to mupirocin.

Among CAPD patients who were S aureus nasal carriers, periodic brief treatment with nasal mupirocin after an initial eradication regimen kept them free of carriage, for the most part, with few adverse effects. The pulse mupirocin regimen offers simplicity and possibly better compliance, as well as minimizing exposure to this agent, thereby possibly reducing the risk of resistance. Further studies are warranted to compare this regimen to other commonly used mupirocin maintenance regimens in dialysis patients.

To evaluate the in vitro activity of antiseptics and detergents against Candida.

One strain each of Candida albicans, Candida tropicalis, Candida lusitaniae, Candida parapsilosis, Candida kefyr, Candida glabrata, and an American Type Culture Collection strain of Escherichia coli (control) were studied. Clinical isolates were obtained from patients in a bone marrow unit of a large tertiary hospital. Antiseptic and disinfectant agents studied were used in the hospital where isolates were identified for cleaning of inanimate surfaces or hand washing. In vitro susceptibility was determined using a broth macrodilution method with exposure times to antiseptic or disinfectant agent of 15 seconds to 4 minutes and concentrations of agents that ranged from undiluted to 1:10,000 dilution.

A 900-bed teaching hospital.

Of disinfectants tested, Vestal and Sparquat inhibited growth of all species at dilutions of ≤1:100 at all contact times for all species. Clorox showed inhibition of growth at 1:100 dilution after 30 seconds of contact time for all isolates. Of antiseptics studied, Hibiclens inhibited growth of all species except C tropicalis at dilutions of ≤1:100 at all contact times and for C tropicalis after 60 seconds. Clinidine inhibited growth of all species at dilutions of ≤1:100 at all contact times for all species with the exception of C glabrata and C tropicalis, which grew at the undiluted concentration. Ultradex failed to demonstrate killing of any species for any dilutions tested.

The results of this study show varying degrees of in vitro inhibition of growth by a variety of antiseptics and disinfectants against clinical isolates of Candida species from hospitalized patients.

To evaluate the usefulness of repeated prevalence surveys to determine trends in the rates of nosocomial infections and to detect changes in risk factors (eg, use of invasive devices) associated with nosocomial infections.

Ten annual prevalence surveys were conducted by trained infection control practitioners between 1985 and 1995 for acute-care patients on the medical, surgical, pediatric, and obstetric-gynecologic services at a 900-bed, tertiary-care, teaching hospital with 750 acute-care beds. The same methods of chart review and concurrent reporting from nursing, the microbiology and clinical laboratory, and the pharmacy were used each year to collect data on the prevalence of nosocomial infections, invasive-device utilization, and abnormal laboratory indicators. Although data were collected on a single day, a period-prevalence study approach was used, because charts were reviewed for any infection data occurring within the 7 days prior to the survey.

The hospital census for acute-care patients, as measured by the prevalence surveys, declined sharply over the 10 years, from 673 to 575 patients (P=.02). However, the medical service census increased from 150 to 188 patients (P=.01). During the same period, there was a significant decrease in the mean length of stay, from 7.3 to 6.0 days (P=.01), and a concomitant increase in the mean diagnosis-related-group case-mix index, from 1.03 to 1.24 (P=.001). Overall, nosocomial infection rates remained unchanged over the study period (mean of 9.85 infections per 100 patients), but rates of nosocomial bloodstream infection increased from 0.0% in 1985 to 2.3% in 1995 (P=.05). Nosocomial infection rates were significantly higher on the medical and surgical services than on other services (P<.001). Utilization rates increased significantly for Foley catheters (9.0% to 16.0%, P=.002) and ventilators (5.0% to 8.0%, P=.05).

Despite apparent increases in the severity of illness of our patients, overall rates of nosocomial infection remained stable during a decade of study. Rates of nosocomial bloodstream infection increased, in parallel with National Nosocomial Infection Surveillance System data. We found repeated prevalence surveys to be useful in following trends and rates of infection, device utilization, and abnormal laboratory values among patients at our institution. Such methodologies can be valuable and low-cost components of a comprehensive infection surveillance, prevention, and control program and other potential quality-improvement initiatives, because they enable better annual planning of departmental strategies to meet hospital needs