To compare the occurrence of Clostridium difficile among inpatients infected with human immunodeficiency virus (HPV) in two different hospitals.

Prospective, observational study.

Specialized HPV inpatient units.

HIV-infected inpatients at Cook County Hospital (CCH) and Rush Presbyterian St. Luke's Medical Center (RPSLMC).

A clinical and epidemiologic assessment of patient risk factors for C. difficile was performed. C. difficile isolates found on stool, rectal, and environmental cultures were typed by pulsed-field gel electrophoresis.

Twenty-seven percent of patients admitted to CCH versus 4% of patients admitted to RPSLMC had positive cultures for C. difficile (P = .001). At CCH, 14.7% of environmental cultures were positive versus 2.9% at RPSLMC (P = .002). Risk factors for C. difficile acquisition included hospitalization at CCH, more severe HrV, use of acyclovir and H2-blockers, and longer hospital stay. Patients admitted to CCH were taking more antibiotics, had longer hospital stays, and more frequently had a history of C. difficile infection. During the study, two strains (CD1A and CD4) extensively contaminated the CCH environment. However, only CD1A caused an outbreak.

The C. difficile acquisition rate at CCH was sevenfold higher than that at RPSLMC, and CCH had a more contaminated environment Differences in patient acquisition rates likely reflect a greater prevalence of traditional C. difficile risk factors and a concurrent outbreak at CCH. Although two strains heavily contaminated the environment at CCH, only one caused an outbreak, suggesting that factors other than the environment are important in initiating C. difficile outbreak.

To determine the epidemiology and relatedness of Clostridium difficile isolates in two geographically separated hospitals in a large metropolitan area, each with unique patients and personnel.

Observational descriptive molecular epidemiology of clinical C. difficile isolates.

Two tertiary-care hospitals in Chicago.

Consecutive C. difficile isolates from the clinical laboratory of a Veterans Affairs hospital during a 13-month period were typed by restriction endonuclease analysis (REA). During an overlapping 3-month period, stool specimens that tested positive for C. difficile toxin from patients at a nearby county hospital were cultured and the recovered isolates typed by the same method.

Nineteen (68%) of 28 nosocomial isolates at the smaller, Veterans Affairs hospital belonged to REA group K. Within this group of closely related strains, 9 distinct REA types were recognized. Twenty-one (72%) of 29 nosocomial isolates at the larger, county hospital also belonged to group K. However, the predominant REA types within group K differed markedly at each institution.

These findings demonstrate a high degree of similarity among nosocomial C. difficile strains from different hospitals in the same city and suggest the possibility of an extended outbreak of a prototype group K strain with subsequent genetic drift at the two different institutions.

To determine the diagnostic accuracy of an index of underlying disease severity (Horn's index) in identifying patients with a high probability of having nosocomial Clostridium difficile diarrhea as a complication of antimicrobial therapy.

A prospective cohort study of 252 adult patients admitted to the hospital and receiving antibiotics. Risk factors for C. difficile diarrhea were first determined retrospectively in a different cohort of 300 hospitalized patients (primary cobort) and then prospectively in this cohort of 252 hospitalized patients receiving antibiotics (secondary cohort). At the time of hospital admission, disease was rated by clinicians as mild (1), moderate (2), severe (3), or extremely severe (4) using a modified Horn's index. Multivariable logistic regression analysis was used to determine the odds ratio (OR) for C. difficile diarrhea associated with increasing levels of disease severity.

An urban teaching hospital affiliated with a medical school in Boston, Massachusetts.

The incidence of nosocomial C. difficile diarrhea was 8.7% in the primary cohort and 11% in the secondary cohort. In the prospective cohort study (secondary cohort), the OR for C. difficile diarrhea associated with extremely severe disease was 17.6 (95% confidence interval, 5.8 to 53.5). The sensitivity, specificity, and positive and negative predictive values of a Horn's index score of 3 or more (severe to extremely severe disease) as a predictor of nosocomial C. difficile diarrhea were 79%, 73%, 27%, and 96%, respectively.

These findings provide a means of early stratification of hospitalized patients receiving antibiotics according to their risk for nosocomial C. difficile diarrhea. Patients with severe to extremely severe disease at the time of admission may benefit from careful monitoring of antibiotic prescribing and early attention to infection control issues. In the future, these “high-risk” patients may benefit from prophylaxis studies of novel agents being developed to prevent C. difficile diarrhea.

We report surveillance of nosocomial diarrhea in children at our institution during the past decade and note different epidemiology of diarrhea due to viruses and Clostridium difficile.

A prospective cohort study.

A university-affiliated pediatric hospital with 180 beds serving an urban area and providing referral care for the Maritime Provinces of Canada.

Children younger than 18 years.

Surveillance was conducted from 1991 to 1999 using personal contact with personnel and review of microbiology and medical records. Nosocomial diarrhea was defined as loose stools occurring more than 48 hours after admission, with at least two loose stools in 12 hours and no likely non-infectious cause.

Nosocomial diarrhea was the third most common nosocomial infection (217 of 1,466; 15%), after bloodstream and respiratory infections, with from 0.5 to 1 episode per 1,000 patient-days. Of 217 nosocomial diarrhea episodes, 122 (56%) had identified pathogens: C. difficile (39 of 122; 32%), rotavirus (38 of 122; 31%), adenovirus (36 of 122; 30%), and other viral (9 of 122; 7%). The median age was 1.3 years (range, 11 days to 17.9 years), 0.80 year for children with viral diarrhea, 3.9 years for children with C. difficile, and 1.5 years for children with diarrhea without a causative organism identified (P< .0001). Most children with nosocomial diarrhea were incontinent (diapered) at the time of their first episode (138 of 185; 75%), but preexisting incontinence was more common in those with viral diarrhea (93%) compared with those with no organism identified (71%) or those with C. difficile-associated diarrhea (CDAD) (49%) (P< .0001).

C. difficile is the single most common cause of nosocomial diarrhea in our tertiary-care center, although all viral pathogens account for 69% of cases. Diapered status appears to be a risk factor for CDAD in children, and CDAD occurs more often in older children than viral nosocomial diarrhea. Further characterization of risk factors for, and morbidity associated with, nosocomial CDAD in children is warranted.

In December 1999, an outbreak of diarrhea was reported in a general hospital neonatal medium care unit (NMCU) caused by a novel strain of rotavirus with genotype P[6], G9. An investigation was conducted to determine risk factors for illness among neonates.

Rotavirus diagnosis was by latex agglutination and typing by reverse transcriptase polymerase chain reaction. A case-control study was performed using data collected from medical records on exposures in a 3-day period before illness (cases) or a random 3-day period (controls). Environmental swabs were tested for rotavirus. Antenatal blood samples from mothers and blood samples provided by hospital staff were analyzed for rotavirus antibodies.

Fifty-six cases of rotaviral illness were confirmed by latex agglutination. Forty-seven of these were among 118 neonates exposed to the NMCU (attack rate, 40%). There was a 4-week period with no clinical cases in the course of the outbreak. Increased frequency (s≥ 15 times in 3 days) of ungloved nasogastric feeding was a significant risk factor (adjusted odds ratio, 8.79), controlling for birth weight and gestational age. Environmental sampling showed persistence of the virus on ward surfaces despite cleaning. None of 24 NMCU staff members had high levels of antibodies against P[6], G9. Three (8%) of 38 mothers had high antibody levels; 2 had infants who became ill. The outbreak ended with a 7-day ward closure, disinfection, and introduction of gloved nasogastric feeding.

Case-control studies can be successful in identifying risk factors for nosocomial outbreaks of diarrhea. High levels of rotavirus antibodies in mothers may not protect infants. The environment may be the most important reservoir of rotavirus during outbreaks.

To describe a nosocomial outbreak of Salmonella serotype Saintpaul gastroenteritis and to explore risk factors for infection.

Case-control study.

A 208-bed, university-affiliated children's hospital.

Patients hospitalized at Children's Hospital and Regional Medical Center, Seattle, Washington, during February 2001 who had stool specimens obtained for culture at least 24 hours after admission. Case-patients (n = 11) were patients with an indistinguishable strain of Salmonella Saintpaul cultured from their stool. Control-patients (n = 41) were patients hospitalized for problems other than gastroenteritis whose stool cultures were negative for Salmonella.

Risk factors were evaluated using the chisquare test or Fisher's exact test. Continuous variables were compared using the Mann–Whitney U test. A multivariable analysis was performed using logistic regression. The predictor of interest was the receipt of enteral feeding formula mixed by the hospital.

Case-patients were more likely than control-patients to have received formula mixed by the hospital (OR, 4.2; 95% confidence interval, 1.04 to 17.16). Other variables evaluated were not significant predictors of Salmonella Saintpaul infection.

Formula mixed by the hospital appears to have been the source of this Salmonella outbreak. Strict sanitation measures must be ensured in formula preparation and delivery, and bacterial pathogens should be included in the differential diagnosis for nosocomial gastroenteritis.

When the incidence of methicillin-susceptible Staphylococcus aureus (MSSA) infection or colonization increased in our neonatal intensive care unit (NICU), we sought to further our understanding of the relationship among colonization with MSSA, endemic infection, and clonal spread.

A retrospective cohort study was used to determine risk factors for acquisition of a predominant clone of MSSA (clone “B”).

A 45-bed, university-affiliated, level III-IV NICU.

Infants hospitalized in the NICU from October 1999 to September 2000.

Infection control strategies included surveillance cultures of infants, cohorting infected or colonized infants, contact precautions, universal glove use, mupirocin treatment of the anterior nares of all infants in the NICU, and a hexachlorophene bath for infants weighing 1,500 g or more.

During the 1-year study period, three periods of increased incidence of MSSA colonization or infection, ranging from 6.4 to 13.5 cases per 1,000 patient-days per month, were observed. Molecular typing using pulsed-field gel electrophoresis demonstrated two predominant clones, clone “B” and clone “G,” corresponding to two periods of increased incidence. Multivariate analysis demonstrated that length of stay (OR, 1.035; 95% confidence interval [CI95], 1.008 to 1.062; P = .010) (increased risk per day) and the use of H2-blockers (OR, 20.44; CI95, 2.48 to 168.26; P = .005) were risk factors for either colonization or infection with clone “B,” and that the use of peripheral catheters was protective (OR, 0.06; CI95, 0.01 to 0.43; P = .005).

Control of MSSA represents unique challenges as colonization is expected, endemic infections are tolerated, and surveillance efforts generally focus on multidrug-resistant pathogens. Future studies should address cost-effective surveillance strategies for endemic infections.

In Oregon in 1994, a population-based study of 66 nonpsychiatric hospitals indicated that 40% of vancomycin orders were inappropriate according to Centers for Disease Control and Prevention guidelines. We repeated the study to determine whether vancomycin use had been affected by pharmacy policies implemented following the 1994 study.

We surveyed pharmacists in nonpsychiatric hospitals in Oregon regarding vancomycin use policies in their hospitals. Using pharmacy records, we identified and abstracted the charts of all patients in Oregon hospitals receiving vancomycin during a 3-week period to determine appropriate use of vancomycin.

Thirteen (20%) of 64 hospitals had implemented a vancomycin restriction policy since 1994; none of the remaining hospitals in the study had a policy. In 1999, hospitals with vancomycin restriction policies had substantially decreased rates of inappropriate vancomycin use compared with hospitals without such policies (1.0 vs 1.8 orders per 1,000 patient-days; P = .01). Compared with 1994 baseline rates of inappropriate use, hospitals that adopted policies experienced a decrease (from 1.5 orders per 1,000 patient-days in 1994 to 1.0 in 1999; P= .13), whereas hospitals without policies experienced a statistically significant increase (from 0.9 orders per 1,000 patient-days in 1994 to 1.8 in 1999; P = .001). Restriction policies were most effective at reducing rates of inappropriate use for treatment of confirmed gram-positive infections and prophylaxis.

Vancomycin restriction policies were associated with a decrease in inappropriate therapeutic and prophylactic vancomycin use, but had no effect on inappropriate empiric use. Hospitals considering limits regarding inappropriate use should consider implementation of institution-based vancomycin restriction policies as part of an overall strategy.