To determine the timing of community-onset Clostridium difficile–associated disease (CDAD) relative to the patient's last healthcare facility discharge, the association of postdischarge cases with healthcare facility–onset cases, and the influence of postdischarge cases on overall rates and interhospital comparison of rates of CDAD.

Retrospective cohort study for the period January 1, 2005, through December 31, 2005.

Catchment areas of 6 acute care hospitals in North Carolina.

We reviewed medical and laboratory records to determine the date of symptom onset, the dates of hospitalization, and stool C. difficile toxin assay results for patients with CDAD who had diarrhea and positive toxin–assay results. Cases were classified as healthcare facility–onset if they were diagnosed more than 48 hours after admission. Cases were defined as community-onset if they were diagnosed in the community or within 48 hours after admission, and were also classified on the basis of the time since the last discharge: if within 4 weeks, community-onset, healthcare facility–associated (CO-HCFA); if 4-12 weeks, indeterminate exposure; and if more than 12 weeks, community-associated. Pearson's correlation coefficient was used to assess the association between monthly rates of healthcare facility–onset, healthcare facility–associated (HO-HCFA) cases and CO-HCFA cases. We performed interhospital rate comparisons using HO-HCFA cases only and using both HO-HCFA and CO-HCFA cases.

Of 1046 CDAD cases, 442 (42%) were HO-HCFA cases and 604 (58%) were community-onset cases. Of the 604 community-onset cases, 94 (15%) were CO-HCFA, 40 (7%) were of indeterminate exposure, and 208 (34%) community-associated. A modest correlation was found between monthly rates of HO-HCFA cases and CO-HCFA cases across the 6 hospitals (r = 0.63, P<.001). Interhospital rankings changed for 6 of 11 months if CO-HCFA cases were included.

A substantial proportion of community-onset cases of CDAD occur less than 4 weeks after discharge from a healthcare facility, and inclusion of CO-HCFA cases influences interhospital comparisons. Our findings support the use of a proposed definition of healthcare facility–associated CDAD that includes cases that occur within 4 weeks after discharge.

To describe variability in rates of antibacterial use in a large sample of US hospitals and to create risk-adjusted models for interhospital comparison.

We retrospectively surveyed the use of 87 antibacterial agents on the basis of electronic claims data from 130 medical-surgical hospitals in the United States for the period August 2002 to July 2003; these records represented 1,798,084 adult inpatients. Hospitals were assigned randomly to the derivation data set (65 hospitals) or the validation data set (65 hospitals). Multivariable models predicting rates of antibacterial use were created using the derivation data set. These models were then used to predict rates of antibacterial use in the validation data set, which was compared with observed rates of antibacterial use. Rates of antibacterial use was measured in days of therapy per 1,000 patient-days.

Across the surveyed hospitals, a mean of 59.3% of patients received at least 1 dose of an antimicrobial agent during hospitalization (range for individual hospitals, 44.4%-73.6%). The mean total rate of antibacterial use was 789.8 days of therapy per 1,000 patient-days (range, 454.4-1,153.4). The best model for the total rate of antibacterial use explained 31% of the variance in rates of antibacterial use and included the number of hospital beds, the number of days in the intensive care unit per 1,000 patient-days, the number of surgeries per 1,000 discharges, and the number of cases of pneumonia, bacteremia, and urinary tract infection per 1,000 discharges. Five hospitals in the validation data set were identified as having outlier rates on the basis of observed antibacterial use greater than the upper bound of the 90% prediction interval for predicted antibacterial use in that hospital.

Most adult inpatients receive antimicrobial agents during their hospitalization, but there is substantial variability between hospitals in the volume of antibacterials used. Risk-adjusted models can explain a significant proportion of this variation and allow for comparisons between hospitals for benchmarking purposes.

To determine whether methodological differences explain divergent results in case-control studies examining surgery as a risk factor for Creutzfeldt-Jakob disease (CJD).

After case-control studies were systematically identified using PubMed, we performed a homogeneity analysis and applied models to effect sizes (odds ratio [OR] with 95% confidence interval [CI]) using 2 parameters: type of control subject used and consistency of data ascertainment. The hospitals and communities were located in Europe, Japan, and Australia. Patients were CJD case subjects and age- and sex-matched control subjects in the hospital or community. Because of the natural history of the disease, CJD subjects are not considered reliable sources of information for these studies. Therefore, individuals who are considered close to the subjects and who have knowledge of their medical history, including spouses and relatives, are necessarily identified as proxy informants for the surgical record of the case subjects.

Overall, the effect sizes lacked homogeneity (P<.0001). Three studies that used control subjects from the community revealed a significantly elevated risk of CJD for patients who underwent surgery (OR, 1.82; 95% CI, 1.41-2.35 [P<.0001 ]), whereas 3 investigations that used control subjects from the hospital revealed a significantly reduced risk (OR, 0.69; 95% CI, 0.52-0.90 [P = .0069]). Two studies that used proxy informants to acquire information about case subjects and control subjects (consistent ascertainment) found that the risk of CJD was significantly lower in those subjects who underwent surgery (OR, 0.65; 95% CI, 0.48-0.87 [P = .0043]). Conversely, 4 studies in which proxy informants acted only on behalf of case subjects (inconsistent data ascertainment) found a significant positive association between surgery and CJD (OR, 1.67; 95% CI, 1.32-2.12 [P<.0001 ]). Both models fit the data very well, leaving no remaining variance in effect sizes to explain.

Variation in the type of control subjects used and in exposure assessment in case-control studies may partially explain conflicting data regarding the association between surgery and CJD. However, there was almost complete confounding of these 2 parameters, making interpretation more difficult. Planning of future investigations must carefully consider these design elements.

To describe rates of surgical site infection (SSI) after hip replacement and to use these data to provide a simple mechanism for identifying poorly performing hospitals that takes into account variations in sample size.

Prospective surveillance study.

A total of 125 acute care hospitals in England that participated in mandatory SSI surveillance from April 1, 2004 through March 31, 2005.

Patients who underwent total hip replacement (THR) or hip hemiarthroplasty (HH).

A standard data set was collected for all eligible operations at participating hospitals for a minimum of 3 months annually. Defined methods were used to identify SSIs that occurred during the inpatient stay. Data were checked for quality and accuracy, and funnel plots were constructed by plotting the incidence of SSI against the number of operations.

Data were collected on 16,765 THRs and 5,395 HHs. The cumulative SSI incidence rates were 1.26% for THR and 4.06% for HH; the incidence densities were 1.38 SSIs per 1,000 postoperative inpatient days for THR and 2.3 SSIs per 1,000 postoperative inpatient days for HH. The risk of infection associated with revision surgery was significantly higher than that associated with primary surgery (2.7% [95% confidence interval, 2.0%-3.5%] vs. 1.1% [95% confidence interval, 1.0%-1.2%];P = .003). Rates varied considerably among hospitals. Nineteen hospitals had rates above the 90th percentile. However, the use of funnel plots to adjust for the precision of estimated SSI rates identified 7 hospitals that warranted further investigation, including 2 with crude rates below the 90th percentile.

Funnel plots of rates of SSI after hip replacement provide a valuable method of presenting hospital performance data, clearly identifying hospitals with unusually high or low rates while adjusting for the precision of the estimated rate. This information can be used to target and support local interventions to reduce the risk of infection.

To evaluate whether the adjusted rates of surgical site infection (SSI) and urinary tract infection (UTI) after cesarean delivery decrease in maternity units that perform active healthcare-associated infection surveillance.

Trend analysis by means of multiple logistic regression.

A total of 80 maternity units participating in the Mater Sud-Est surveillance network.

A total of 37,074 cesarean deliveries were included in the surveillance from January 1, 1997, through December 31, 2003.

We used a logistic regression model to estimate risk-adjusted post–cesarean delivery infection odds ratios. The variables included were the maternity units' annual rate of operative procedures, the level of dispensed neonatal care, the year of delivery, maternal risk factors, and the characteristics of cesarean delivery. The trend of risk-adjusted odds ratios for SSI and UTI during the study period was studied by linear regression.

The crude rates of SSI and UTI after cesarean delivery were 1.5% (571 of 37,074 patients) and 1.8% (685 of 37,074 patients), respectively. During the study period, the decrease in SSI and UTI adjusted odds ratios was statistically significant (R = −0.823 [P = .023] and R = −0.906 [P = .005], respectively).

Reductions of 48% in the SSI rate and 52% in the UTI rate were observed in the maternity units. These unbiased trends could be related to progress in preventive practices as a result of the increased dissemination of national standards and a collaborative surveillance with benchmarking of rates.

To describe the epidemiology of hospital-acquired infections (HAIs) in veterans with spinal cord injury and disorder (SCI&D).

Retrospective medical record review.

Midwestern Department of Veterans Affairs spinal cord injury center.

A total of 226 patients with SCI&D hospitalized at least once during a 2-year period (October 1, 2001, through September 30, 2003).

A total of 549 hospitalizations were included in the analysis (mean duration of hospitalization, 33.7 days); an HAI occurred during 182 (33.2%) of these hospitalizations. A total of 657 HAIs occurred during 18,517 patient-days in the hospital (incidence rate, 35.5 HAIs per 1,000 patient-days). Almost half of the 226 patients had at least 1 HAI; the mean number of HAIs among these patients was 6.0 HAIs per patient. The most common HAIs were urinary tract infection (164 [25.0%] of the 657 HAIs; incidence rate, 8.9 cases per 1,000 patient-days), bloodstream infection (111 [16.9%]; incidence rate, 6.0 cases per 1,000 patient-days), and bone and joint infection (103 [15.7%]; incidence rate, 5.6 cases per 1,000 patient-days). The most common culture isolates were gram-positive bacteria (1,082 [45.6%] of 2,307 isolates), including Staphylococcus aureus, and gram-negative bacteria (1,033 [43.6%] of isolates), including Pseudomonas aeruginosa. Multivariate regression demonstrated that predictors of HAI were longer length of hospital stay (P = .002), community-acquired infection (P = .007), and use of a urinary invasive device (P = .01) or respiratory invasive device (P = .04).

The overall incidence of HAIs in persons with SCI&D was higher than that reported for other populations, confirming the increased risk of HAI in persons with spinal cord injury. The increased risk associated with longer length of stay and with community-acquired infection suggests that strategies are needed to reduce the duration of hospitalization and to effectively treat community-acquired infection, to decrease infection rates. There is significant room for improvement in reducing the incidence of HAIs in this population.

To better define the pathogenesis of catheter-related bloodstream infection (BSI) in neonates with peripherally inserted central venous catheters (PICCs) to guide the development of more effective strategies for prevention.

Prospective nested cohort study.

Level III neonatal intensive care unit in a community hospital.

During a randomized trial to assess the safety and efficacy of a prophylactic vancomycin-heparin catheter-lock solution for the prevention of catheter-related BSI in neonates with PICCs, we performed cultures of peripheral and catheter-drawn blood samples, and quantitative cultures of catheter hub samples if BSI was suspected clinically. We performed semiquantitative cultures of the catheter tip and the catheter hub and the skin at the insertion site when the catheter was removed. Molecular subtyping by pulsed-field electrophoresis was used to determine the probable pathogenesis of all BSIs due to coagulase-negative staphylococci (CoNS); for BSIs caused by other microorganisms, epidemiologic concordance was based on speciation and antibiograms. Catheter-related BSI was considered extraluminally acquired if concordance was demonstrable solely between isolates recovered from the catheter tip and the blood, independent of concordance with isolates recovered from the insertion site. Catheter-related BSI was considered intraluminally acquired if concordance was demonstrated only between isolates recovered from the catheter hub and the blood. The source of the infection was considered indeterminate if both concordance patterns were present.

Nosocomial BSI was identified in 23 of the 82 neonates in the cohort. Fifteen of these infections, 14 of which were caused by CoNS, were considered definite or probable catheter-related BSIs. Catheter-related BSI was intraluminally acquired in 10 (67%) of 15 patients, extraluminally acquired in 3 (20%), and indeterminate in 2 (13%).

Most catheter-related BSIs in neonates with PICCs are caused by CoNS and derive from intraluminal contamination. Strategies for prevention of catheter-related BSI directed at this predominant mechanism of infection are most likely to be effective.

To investigate the epidemiology of multidrug-resistant Enterobacteriaceae (MDRE) in hospitalized infants.

From 2000 through 2005, active surveillance cultures for MDRE were performed for patients admitted to a 40-bed neonatal intensive care unit (NICU) that provides care for critically ill infants 6 months of age or younger. MDRE epidemiology and the genetic relatedness of MDRE strains determined by repetitive-sequence polymerase chain reaction were analyzed.

Active surveillance cultures revealed that 759 (23%) of 3,370 NICU infants (or approximately 1 in 5) developed MDRE colonization or infection and that 613 (72%) of the 853 isolates with epidemiologic data available were healthcare acquired. MDRE colonization occurred more frequently (in 653 infants [86%]) than did MDRE infection (in 106 [14%]). Of the 653 infants with MDRE colonization, 119 (18%) eventually became infected, with 29 (4%) acquiring sterile site infections. The most commonly isolated organisms were the Enterobacter species, accounting for 612 (71%) of the 862 isolates. Molecular epidemiologic analysis revealed that genetic-relatedness clustering (related clusters defined as having a genetic similarity coefficient greater than 95%) varied depending on microbial species. Clustering was detected for 36 (78%) of the 46 Enterobacter aerogenes isolates, 22 (45%) of the 49 Enterobacter cloacae isolates, and 13 (59%) of the 22 Klebsiella pneumoniae isolates.

Hospitalized infants are at significant risk of acquiring MDRE, specifically Enterobacter species, at the study institution. Active surveillance cultures identified colonized patients who likely contributed to the institutional reservoir of MDRE. Molecular epidemiologic studies suggest that both patient-to-patient transmission and de novo acquisition of resistance play a role in the acquisition of these organisms, and that the clinical significance of such acquisition varies by species. The high percentage of E. aerogenes isolates that demonstrated genetic clustering suggests that monitoring the prevalence of this organism could serve as a useful measure of compliance with infection control procedures.

To determine the rate of influenza vaccination and the factors associated with the vaccination's acceptance among nurses in Hong Kong.

Cross-sectional survey.

Nurses practicing between 2003 and 2007.

A questionnaire was sent to all nurses registered with any of the 3 nursing associations that participated in this study.

A total of 941 completed questionnaires were available for analysis, though not all nurses responded to every question (response rate, 33.5%-36.3%). Vaccination rates in 2006 and 2007 were 57.2% and 46.2%, respectively. Nurses who were vaccinated in 2006 were more likely to get vaccinated in 2007 (P<.01); 56% of the nurses perceived influenza vaccine as being effective against influenza. The perceived effectiveness of influenza vaccine was a consistent predictor of rates of vaccination in 2006 (odds ratio [OR], 8.47 [95% confidence interval {CI}, 6.13-11.70]; P<.01) and 2007 (OR, 6.05 [95% CI, 3.79-9.67]; P<.01). Concern about contracting avian influenza was a predictor of the vaccination rate in 2006 but not in 2007 (OR, 1.47 [95% CI, 1.03-2.09]; P<.05), as was the perceived lack of control over avian influenza infection (OR, 1.52 [95% CI, 1.06-2.18]; P<.05).

The overall influenza vaccination rate for nurses in Hong Kong was about 50%. It was affected by the perceived threat of an impending outbreak. The attitudes of nurses toward the effectiveness of and rationale for vaccination were a major barrier to increasing the rate of vaccination.

To assess published hand hygiene behavioral interventions that employed a social marketing framework and to recommend improvements to future interventions.

We performed a systematic literature review by searching the PubMed database and the Cumulative Index to Nursing and Allied Health Literature for published articles about hand hygiene behavioral interventions in healthcare facilities, schools, and community settings. Our analysis included articles that describe multifaceted interventions and evaluated them with predefined social marketing benchmark criteria.

Of 53 interventions analyzed in this review, 16 (30.2%) employed primary formative audience research, 5 (9.4%) incorporated social or behavioral theories, 27 (50.9%) employed segmentation and targeting of the audience, 44 (83.0%) used components of the “marketing mix,” 3 (5.7%) considered the influence of competing behaviors, 7 (13.2%) cultivated relationships with the target audience, and 15 (28.3%) provided simple behavioral messages. Thirty-five (66.0%) of the interventions demonstrated a significant improvement in performance, but only 21 (39.6%) were considered to have a strong evaluative design. The median duration of the interventions was 8.0 months.

From a social marketing perspective, the promotion of hand hygiene could be improved in several ways. The effectiveness of social marketing in hand hygiene promotion should be tested in future interventions.