Clostridium difficile-associated diarrhea (CDAD) causes substantial healthcare-associated morbidity. Unlike other common healthcare-associated pathogens, little comparative information is available about CDAD rates in hospitalized patients.

To determine CDAD rates per 10,000 patient-days and per 1,000 hospital admissions at 7 geographically diverse tertiary-care centers from 2000 to 2003, and to survey participating centers on methods of CDAD surveillance and case definition.

Each center provided specific information for the study period, including case numbers, patient-days, and hospital characteristics. Case definitions and laboratory diagnoses of healthcare-associated CDAD were determined by each institution. Within institutions, case definitions remained consistent during the study period.

Overall, mean annual case rates of CDAD were 12.1 per 10,000 patient-days (range, 3.1 to 25.1) and 7.4 per 1,000 hospital admissions (range, 3.1 to 13.1). No significant increases were observed in CDAD case rates during the 4-year interval, either at individual centers or in the Prevention Epicenter hospitals as a whole. Prevention Epicenter hospitals differed in their CDAD case definitions. Different case definitions used by the hospitals applied to a fixed data set resulted in a 30% difference in rates. No associations were identified between diagnostic test or case definition used and the relative rate of CDAD at a specific medical center.

Rates of CDAD vary widely at tertiary-care centers across the United States. No significant increases in case rates were identified. The varying clinical and laboratory approaches to diagnosis complicated comparisons between hospitals. To facilitate benchmarking and comparisons between institutions, we recommend development of a more standardized case definition.

Clostridium difficile-associated diarrhea (CDAD) is an important infection in hospital settings. Its impact on outpatient care has not been well defined.

To examine risk factors of ambulatory cancer patients with CDAD.

Case-control study.

Memorial Sloan-Kettering Cancer Center, a tertiary-care hospital.

Cases of CDAD among oncology outpatients from January 1999 through December 2000 were identified via positive C. difficile toxin assay results on stool specimens sent from clinics or the emergency department. A 1:3 matched case-control study examined exposures associated with CDAD.

Forty-eight episodes of CDAD were identified in cancer outpatients. The mean age was 51 years; 44% were female. Forty-one (85%) had received antibiotics within 60 days of diagnosis, completing courses a median of 16.5 days prior to diagnosis. Case-patients received longer courses of first-generation cephalosporins (4.8 vs 3.2 days; P = .03) and fluoroquinolones (23.6 vs 8 days; P < .01) than did control-patients. Those receiving clindamycin were 3.9-fold more likely to develop CDAD (P < .01). For each additional day of clindamycin or third-generation cephalosporin exposure, patients were 1.29- and 1.26-fold more likely to develop CDAD (P < .01 and .04, respectively). The 38 CDAD patients hospitalized during the risk period (79.2%) spent more time as inpatients than did control-patients (19.3 vs 9.7 days; P <. 001).

Antibiotic use, especially with cephalosporins and clindamycin, and prolonged hospitalization contributed to the development of CDAD. Outpatient CDAD appears to be most strongly related to inpatient exposures; reasons for the delayed development of symptoms are unknown.

Clostridium difficile is the most common cause of infectious nosocomial diarrhea and can be found in up to 30% of asymptomatic hospitalized patients. Our primary aim was to compare the clinical characteristics of hospitalized patients who received antibiotics and developed C. difficile-associated diarrhea (CDAD) with those of hospitalized patients who received antibiotics and did not develop the disease.

Case-control study comprising inpatients at a single institution.

Case-patients were defined as patients who had diarrhea and tested positive for C. difficile. Control-patients (matched 4:1 to case-patients) were defined as patients who received antibiotics for at least 5 days and did not develop CDAD.

On univariate analysis, nine variables were associated with CDAD. Only three of the variables, need for intensive care, length of stay, and macrolide antibiotic use, were found to be significant (P < .05) on logistic regression analysis. The odds ratios for status as a CDAD case were 3.68 (CI95, 1.44 to 9.40) for stay in the intensive care unit and 1.03 (CI95, 1.02 to 1.05) for each day of hospital stay. Receipt of macrolide antibiotics reduced risk significantly; the odds ratio was 0.23 (CI95, 0.19 to 0.87).

We identified need for intensive care and length of stay as important risk factors for the development of CDAD. We also identified macrolide antibiotic use as protective against its development. Patients receiving intensive care may represent a population to study for targeted prophylaxis.

To examine the usefulness of temporal and spatial analysis in identifying nosocomial transmission of Clostridium difficile among pediatric patients hospitalized on four wards at The Children's Hospital of Central California from September 8,1998, to January 16,1999.

Stool specimens obtained from the clinical microbiology laboratory during the study period were tested by culture and latex agglutination for C. difficile. Polymerase chain reaction was used to identify toxin genes. Isolates obtained were mapped to a grid for each ward and were analyzed using the Knox test. Results were compared with DNA fingerprints generated by arbitrarily primed polymerase chain reaction.

Total occupancy of these 4 wards was 438 during the study period. Stool specimens were available for 256 (58%) of these patients, yielding 67 C. difficile isolates and generating 2,211 case pairs for analysis by the Knox test. After stratification by toxin status, 5 clustered pairs of toxigenic isolates were identified on 1 of the wards by this method. Fingerprint analysis identified 4 clusters with indistinguishable banding patterns on 2 of the 4 wards. Two of the identified clusters were toxigenic and 2 were nontoxigenic. None of these clusters corresponded to clusters identified by the Knox test.

The Knox test is an ineffective method for identifying cases resulting from nosocomial transmission of C. difficile in a pediatric setting due to the persistence of C. difficile spores and the unique environment of a pediatric hospital. Molecular analysis remains the most effective method.

To describe the epidemiology of nosocomial coagulase-negative staphylococci (CoNS) bacteremia and to evaluate the clinical significance of a single blood culture positive for CoNS.

A 3-year retrospective cohort study based on data prospectively collected through hospital-wide surveillance. Bacteremia was defined according to CDC criteria, except that a single blood culture growing CoNS was not systematically considered as a contaminant. All clinically significant blood cultures positive for CoNS nosocomial bacteremia were considered for analysis.

A large university teaching hospital in Geneva, Switzerland.

A total of 2,660 positive blood cultures were identified. Of these, 1,108 (41.7%) were nosocomial; CoNS were recovered from 411 nosocomial episodes (37.1%). Two hundred thirty-four episodes of CoNS bacteremia in the presence of signs of sepsis were considered clinically relevant and analyzed. Crude mortality and associated mortality were 24.4% and 12.8%, respectively. Associated mortality was similar among patients with one positive blood culture and those with two or more (16.2% vs 10.8%, respectively; P = .3). Mortality rates after bacteremia for patients with a single positive blood culture and for those with two or more were 15.3% and 7.0%, respectively, at day 14 (RR, 2.2; CI%, 0.87-5.46) and 20.8% and 11.3%, respectively, at day 28 (RR, 1.9; CI95, 0.9-3.8). On multivariate analysis, only age and a rapidly fatal disease were independently associated with death.

CoNS bacteremia harbor a significant mortality and a single positive blood culture in the presence of signs of sepsis should be considered as clinically relevant.

To determine the efficacy and tolerability of octenidine hydrochloride, a non-alcoholic skin antiseptic, for the care of central venous catheter (CVC) insertion sites.

Prospective, observational study.

Bone marrow transplantation unit of a university hospital.

All consecutive patients with a nontunneled CVC were enrolled prospectively after informed consent.

Octenidine hydrochloride (0.1%) was applied for disinfection at the CVC insertion site during dressing changes. The following cultures were performed weekly as well as at the occurrence of any systemic inflammatory response syndrome criteria: cultures of the skin surrounding the CVC entry site, cultures of the three-way hub connected to the CVC, blood cultures, and cultures of the CVC tip on removal. Enhanced microbiological methods (skin swabs of a 24-cm2 standardized area, roll plate, and sonication of catheter tips) were applied.

One hundred thirty-five CVCs were inserted in 62 patients during the study period and remained for a mean period of 19.1 days, corresponding to 2,462 catheter-days. Bacterial density at the insertion site declined substantially over time, and most cultures became negative 2 weeks after insertion. Only 6 patients had a documented catheter-related bloodstream infection. The incidence density was 2.39 catheter infections per 1,000 catheter-days. No side effects were noted with application of the antiseptic.

Disinfection with a skin antiseptic that contains octenidine hydrochloride is highly active and well tolerated. It leads to a decrease in skin colonization over time and may be a new option for CVC care.

Products containing alcohol are commonly used with intravascular devices at insertion, to remove lipids from occluded intravascular devices used during parenteral nutrition, and increasingly for the prevention and treatment of intravascular device-related bloodstream infection. The effects of alcohol on the integrity of intravascular devices remain unknown.

Two types of widely used commercial peripherally inserted central catheters, one made of polyether-urethane and one made of silicone, were exposed to a 70% etha-nol lock solution for up to 10 weeks. Mechanical testing was performed to identify force-at-break, stress, strain, modulus of elasticity, modulus of toughness, and wall area of ethanol-exposed and control catheters.

No significant differences between exposed and unexposed catheters were identified for any of the mechanical parameters tested except for a marginal reduction in the modulus of elasticity for both polyetherurethane and silicone catheters and minor increases in the wall area of polyetherurethane catheters.

These data indicate that exposure to a 70% ethanol lock solution does not appreciably alter the integrity of selected commercial polyetherurethane and silicone catheters. Given the greatly expanded use of alcoholic solutions with intravascular devices of all types, we believe that manufacturers would be well advised to subject their catheters and other intravascular devices to formal testing of the type employed in this study.

To determine whether the conventional rate for central venous catheter (CVC)-associated bloodstream infection (BSI) accurately reflects risk for patients exposed for a variety of in situ periods.

Intensive care unit patients (n = 1,375) were monitored for 7,467 CVC-days. They were monitored until catheter removal, until diagnosis of CVC-associated BSI, or for 24 hours after discharge.

The BSI rate was 3.7 per 1,000 CVC-days. Ninety-three percent of these patients had CVCs in situ for 1-15 days. These patients were exposed to 59.7% of all CVC-days; the remaining 7% were exposed to 40.3% of all CVC-days. BSI rates stratified by exposure periods of 1-5 and 6-15 days were 2.1 and 4.5 per 1,000 CVC-days, respectively. The rates for 16-30 and 31-320 days were 10.2 and 2.1 per 1,000 CVC-days, respectively. The probability of BSI with a CVC in situ was 6 in 100 by day 15, 14 in 100 by day 25, 21 in 100 by day 30, and 53 in 100 by day 320.

The conventional aggregated rate better reflects the risk for the majority of patients rather than for patients exposed to the majority of CVC-days. It does not reflect the true probability of risk for all exposures, especially beyond 30 days. CVCs in situ from 1 to 15 days had less risk of BSI than CVCs in situ more than 15 days, which may explain why scheduled CVC replacement at days 5 to 7 has not been found beneficial.

To assess the efficacy of a standard cleaning and sterilization protocol employed during reuse of cardiac electrophysiology catheters on the infectivity of duck hepatitis B virus (DHBV; a surrogate for human hepatitis B virus), bovine viral diarrhea virus (BVDV; a surrogate for human hepatitis B virus), and human Coxsackie type B3 virus (CB3).

Public health virology laboratory.

Studies were performed on the distal, electrode-containing segments of 120 electrophysiology catheters previously used in up to 10 clinical procedures. Catheter segments were immersed for 1 hour in blood infected with high titers of DHBV, BVDV, or CB3. After air drying for 2 hours, subgroups of 8 catheters were subjected to no treatment, washing in general-purpose detergent, washing in enzyme cleaner, sterilization in ethylene oxide, or the full protocol of sequential detergent-enzyme cleaner-ethylene oxide exposure. Presence of residual virus was assessed by nucleic acid detection and infectivity studies.

DHBV nucleic acid was detected on catheters after individual steps and the full protocol, whereas BVDV and CB3 nucleic acids were detected after individual steps but not the full protocol. These findings were associated with the presence of infectious DHBV and CB3, but not BVDV, on catheters after washing in detergent or enzyme cleaner. However, ethylene oxide alone or the full protocol reduced infectivity of all three viruses to undetectable levels.

These experimental studies provide strong evidence that appropriate cleaning and sterilization of reused electrophysiology catheters inactivates blood-borne viruses such as hepatitis B and C and Coxsackie type B3.

To assess data on the epidemiology of nosocomial infection (N1) among neurologic intensive care patients.

Prospective periodic surveillance study.

An 8-bed neurologic intensive care unit (ICU).

All those admitted for more than 24 hours during five 3-month periods between January 1999 and March 2003.

Standardized surveillance within the German infection surveillance system.

Three hundred thirty-eight patients with a total of 2,867 patient-days and a mean length of stay of 8.5 days were enrolled during the 15-month study period. A total of 71 NIs were identified among 52 patients. Urinary tract infections (UTIs) were the most frequent N1 (36.6%), followed by pneumonia (29.6%) and bloodstream infections (BSIs) (15.5%). The overall incidence and incidence density of NIs were 21.0 per 100 patients and 24.8 per 1,000 patient-days, respectively. Incidence densities were 9.8 UTIs per 1,000 urinary catheter-days (CI95, 6.4-14.4), 5.6 BSIs per 1,000 central venous catheter-days (CI95, 2.8-10.0), and 12.8 cases of pneumonia per 1,000 ventilation-days (CI95, 8.0-19.7). Device-associated UTI and pneumonia rates were in the upper range of national and international reference data for medical ICUs, despite the intensive infection control and prevention program in operation in the hospital.

Neurologic intensive care patients have relatively high rates of device-associated nosocomial pneumonia and UTI. For a valid comparison of surveillance data and implementation of targeted prevention strategies, we would strongly recommend provision of national benchmarks for the neurologic ICU setting.