To characterize the temporal progression of the monthly incidence of Clostridium difficile infections (CDIs) and to determine whether the incidence of CDI is related to the incidence of seasonal influenza.

A retrospective study of patients in the Nationwide Inpatient Sample during the period from 1998 through 2005.

We identified all hospitalizations with a primary or secondary diagnosis of CDI with use of International Classification of Diseases, 9th Revision, Clinical Modification codes, and we did the same for influenza. The incidence of CDI was modeled as an autoregression about a linear trend. To investigate the association of CDI with influenza, we compared national and regional CDI and influenza series data and calculated cross-correlation functions with data that had been prewhitened (filtered to remove temporal patterns common to both series). To estimate the burden of seasonal CDI, we developed a proportional measure of seasonal CDI.

Time-series analysis of the monthly number of CDI cases reveals a distinct positive linear trend and a clear pattern of seasonal variation (R2 = 0.98). The cross-correlation functions indicate that influenza activity precedes CDI activity on both a national and regional basis. The average burden of seasonal (ie, winter) CDI is 23%.

The epidemiologic characteristics of CDI follow a pattern that is seasonal and associated with influenza, which is likely due to antimicrobial use during influenza seasons. Approximately 23% of average monthly CDI during the peak 3 winter months could be eliminated if CDI remained at summer levels.

Assessments of infectious disease spread in hospitals seldom account for interfacility patient sharing. This is particularly important for pathogens with prolonged incubation periods or carrier states.

We quantified patient sharing among all 32 hospitals in Orange County (OC), California, using hospital discharge data. Same-day transfers between hospitals were considered “direct” transfers, and events in which patients were shared between hospitals after an intervening stay at home or elsewhere were considered “indirect” patient-sharing events. We assessed the frequency of readmissions to another OC hospital within various time points from discharge and examined interhospital sharing of patients with Clostridium difficile infection.

In 2005, OC hospitals had 319,918 admissions. Twenty-nine percent of patients were admitted at least twice, with a median interval between discharge and readmission of 53 days. Of the patients with 2 or more admissions, 75% were admitted to more than 1 hospital. Ninety-four percent of interhospital patient sharing occurred indirectly. When we used 10 shared patients as a measure of potential interhospital exposure, 6 (19%) of 32 hospitals “exposed” more than 50% of all OC hospitals within 6 months, and 17 (53%) exposed more than 50% within 12 months. Hospitals shared 1 or more patient with a median of 28 other hospitals. When we evaluated patients with C. difficile infection, 25% were readmitted within 12 weeks; 41% were readmitted to different hospitals, and less than 30% of these readmissions were direct transfers.

In a large metropolitan county, interhospital patient sharing was a potential avenue for transmission of infectious agents. Indirect sharing with an intervening stay at home or elsewhere composed the bulk of potential exposures and occurred unbeknownst to hospitals.

We sought to identify risk factors for central line-associated bloodstream infection (CLABSI) to describe children who might benefit from adjunctive interventions.

Case-control study of children admitted to the medical-surgical intensive care unit (ICU) or cardiac ICU from January 1, 2004, through December 31, 2007.

Children's Hospital Boston is a freestanding, 396-bed quaternary care pediatric hospital with a 29-bed medical-surgical ICU and a 24-bed cardiac ICU.

Case patients were patients with CLABSI who were identified by means of prospective surveillance. Control subjects were patients with a central venous catheter who were matched by ICU admission date.

Multivariate conditional logistic regression models were used to identify independent risk factors for CLABSI and to derive and to validate a prediction rule.

Two hundred three case patients were matched with 406 control subjects. Independent predictors of CLABSI included duration of ICU central access (odds ratio [OR] for 15 or more days, 18.41 [95% confidence interval {CI} 4.10-82.56]; P < .001), central venous catheter placement in the ICU (OR for 2 or more ICU-placed catheters, 8.63 [95% CI, 2.63-28.38]; P = .001), nonoperative cardiovascular disease (OR, 7.44 [95% CI, 2.13-25.98]; P = .012), presence of gastrostomy tube (OR, 3.48 [95% CI, 1.55-7.79]; P = .003), receipt of parenteral nutrition (OR, 3.12 [95% CI, 1.55-6.32]; P= .002), and receipt of blood transfusion (OR, 2.55 [95% CI, 1.21-5.36]; P = .014). By use of risk factors known before central venous catheter placement, our model predicted CLABSI with a positive predictive value of 54% and a negative predictive value of 79%.

Duration of central access, receipt of parenteral nutrition, and receipt of blood transfusion were confirmed as risk factors for CLABSI among children in the ICU. Newly identified risk factors include presence of gastrostomy tube, nonoperative cardiovascular disease, and ICU placement of central venous catheter. Children with these risk factors may be candidates for adjunctive interventions for CLABSI prevention.

The recent emergence of carbapenem resistance among Enterobacteriaceae is a major threat for hospitalized patients, and effective strategies are needed.

To assess the effect of an intensified intervention, which included active surveillance, on the incidence of infection with carbapenem-resistant Klebsiella pneumoniae.

Sheba Medical Center, a 1,600-bed tertiary care teaching hospital in Tel Hashomer, Israel.

Quasi-experimental study.

The medical records of all the patients who acquired a carbapenem-resistant K. pneumoniae infection during 2006 were reviewed. An intensified intervention was initiated in May 2007. In addition to contact precautions, active surveillance was initiated in high-risk units. The incidence of clinical carbapenem-resistant K. pneumoniae infection over time was measured, and interrupted time-series analysis was performed.

The incidence of clinical carbapenem-resistant K. pneumoniae infection increased 6.42-fold from the first quarter of 2006 up to the initiation of the intervention. In 2006, of the 120 patients whose clinical microbiologic culture results were positive for carbapenem-resistant K. pneumoniae, 67 (56%) developed a nosocomial infection. During the intervention period, the rate of carbapenem-resistant K. pneumoniae rectal colonization was 9%. Of the 390 patients with carbapenem-resistant K. pneumoniae colonization or infection, 204 (52%) were identified by screening cultures. There were a total of 12,391 days of contact precautions, and of these, 4,713 (38%) were added as a result of active surveillance. After initiation of infection control measures, we observed a significant decrease in the incidence of carbapenem-resistant K. pneumoniae infection.

The use of active surveillance and contact precautions, as part of a multifactorial intervention, may be an effective strategy to decrease rates of nosocomial transmission of carbapenem-resistant K. pneumoniae colonization or infection.

Surveillance of nosocomial infections (NIs) is well established in many countries but often does not include gastrointestinal infections. We sought to determine the proportion of NIs among all hospitalized cases for the 4 most prevalent types of gastrointestinal infections in Germany.

We analyzed all notifications of laboratory-confirmed or epidemiologically linked gastrointestinal infections due to norovirus, rotavirus, Salmonella species, and Campylobacter species reported to the Robert Koch Institute in Berlin, Germany, from 2002 through 2008. Infections were considered nosocomial if disease onset was more than 2 days after hospitalization for norovirus, rotavirus, and Salmonella infection and more than 5 days after hospitalization for Campylobacter infection.

During the study period, 710,725 norovirus, 394,500 rotavirus, 395,736 Salmonella, and 405,234 Campylobacter gastrointestinal infections were reported. Excluding cases for which nosocomial status could not be determined, we identified 39,424 (49%) of 80,650 norovirus, 11,592 (14%) of 83,451 rotavirus, 3,432 (8%) of 43,348 Salmonella, and 645 (2%) of 33,503 Campylobacter gastrointestinal infections as definite nosocomial cases. Multivariate analysis confirmed higher risk of gastrointestinal NIs for patients aged more than 70 years (relative risk [RR], 7.0 [95% confidence interval {CI}, 6.7–7.2]; P < .001) and residents of western states (RR, 1.3 [95% CI, 1.2–1.3]; P < .001) and lower risk for female patients (RR, 0.9 [95% CI, 0.9–0.9; P < .001). Yearly NI proportions remained stable except for norovirus.

The investigated gastrointestinal NIs in Germany do not show a clear trend, but they are at high level, revealing potential for public health action and improvement of hospital infection control mainly among older patients. National prevalence studies on gastrointestinal NIs would be of additional value to give more insight on how and where to improve hospital infection control.

To characterize the current economic burden of ventilator-associated pneumonia (VAP) and to determine which services increase the cost of VAP in North American hospitals.

We performed a retrospective, matched cohort analysis of mechanically ventilated patients enrolled in the North American Silver-Coated Endotracheal Tube (NASCENT) study, a prospective, randomized study conducted from 2002 to 2006 in 54 medical centers, including 45 teaching institutions (83.3%).

Case patients with microbiologically confirmed VAP (n = 30) were identified from 542 study participants with claims data and were matched by use of a primary diagnostic code, and subsequently by the Acute Physiology and Chronic Health Evaluation II score, to control patients without VAP (n = 90). Costs were estimated by applying hospital-specific cost-to-charge ratios based on all-payer inpatient costs associated with VAP diagnosis-related groups.

Median total charges per patient were $198,200 for case patients and $96,540 for matched control patients (P <.001); corresponding median hospital costs were $76,730 for case patients and $41,250 for control patients (P = .001). After adjusting for diagnosis-related group payments, median losses to hospitals were $32,140 for case patients and $19,360 for control patients (P = .151). The median duration of intubation was longer for case patients than for control patients (10.1 days vs 4.7 days; P < .001), as were the median duration of intensive care unit stay (18.5 days vs 8.0 days; P < .001) and the median duration of hospitalization (26.5 days vs 14.0 days; P < .001). Examples of services likely to be directly related to VAP and having higher median costs for case patients were hospital care (P < .05) and respiratory therapy (P < .05).

VAP was associated with increased hospital costs, longer duration of hospital stay, and a higher number of hospital services being affected, which underscores the need for bundled measures to prevent VAP.

NASCENT study ClinicalTrials.gov Identifier: NCT00148642.

The strength of the association between intensive care unit (ICU)-acquired nosocomial infections (NIs) and mortality might differ according to the methodological approach taken.

TO assess the association between ICU-acquired NIs and mortality using the concept of population-attributable fraction (PAF) for patient deaths caused by ICU-acquired NIs in a large cohort of critically ill patients.

Eleven ICUs of a French university hospital.

We analyzed surveillance data on ICU-acquired NIs collected prospectively during the period from 1995 through 2003. The primary outcome was mortality from ICU-acquired NI stratified by site of infection. A matched-pair, case-control study was performed. Each patient who died before ICU discharge was defined as a case patient, and each patient who survived to ICU discharge was denned as a control patient. The PAF was calculated after adjustment for confounders by use of conditional logistic regression analysis.

Among 8,068 ICU patients, a total of 1,725 deceased patients were successfully matched with 1,725 control Patients. The adjusted PAF due to ICU-acquired NI for patients who died before ICU discharge was 14.6% (95% confidence interval [CI], 14.4%—14.8%). Stratified by the type of infection, the PAF was 6.1% (95% CI, 5.7%–6.5%) for pulmonary infection, 3.2% (95% CI, 2.8%–3.5%) for central venous catheter infection, 1.7% (95% CI, 0.9%–2.5%) for bloodstream infection, and 0.0% (95% CI, –0.4% to 0.4%) for urinary tract infection.

ICU-acquired NI had an important effect on mortality. However, the statistical association between ICU-acquired NI and mortality tended to be less pronounced in findings based on the PAF than in study findings based on estimates of relative risk. Therefore, the choice of methods does matter when the burden of NI needs to be assessed.

To investigate an outbreak of healthcare-associated Burkholderia cepacia complex (BCC) primary bloodstream infections (BCC-BSI).

Case-crossover study in a public hospital, a university hospital and a private hospital in Rio de Janeiro, Brazil, from March 2006 to May 2006.

Twenty-five patients with BCC-BSI.

After determining the date BCC-BSI symptoms started for each patient, 3 time intervals of data collection were defined, each one with a duration of 3 days: the case period, starting just before BCC-BSI symptoms onset; the control period, starting 6 days before BCC-BSI symptoms onset; and the washout period, comprising the 3 days between the case period and the control period. Exposures evaluated were intravascular solutions and invasive devices and procedures. Potential risk factors were identified by using the McNemar χ2 adjusted test. Cultures of samples of potentially contaminated solutions were performed. BCC strain typing was performed by pulsed-field gel electrophoresis using Spel.

The statistical analysis revealed that the use of bromopride and dipyrone was associated with BCC-BSI. A total of 21 clinical isolates from 17 (68%) of the 25 patients and an isolate obtained from the bromopride vial were available for strain typing. Six pulsotypes were detected. A predominant pulsotype (A) accounted for 11 isolates obtained from 11 patients (65%) in the 3 study hospitals.

Our investigation, using a case-crossover design, of an outbreak of BCC-BSI infections concluded it was polyclonal but likely caused by infusion of contaminated bromopride. The epidemiological finding was validated by microbiological analysis. After recall of contaminated bromopride vials by the manufacturer, the outbreak was controlled.

Adherence to hand hygiene among healthcare workers (HCWs) is widely believed to be a key factor in reducing the spread of healthcare-associated infection. The objective of this study was to evaluate the impact of a multifaceted intervention to increase rates of adherence to hand hygiene among HCWs and to assess the effect on the incidence of hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) colonization.

Cluster-randomized controlled trial.

Thirty hospital units in 3 tertiary care hospitals in Hamilton, Ontario, Canada.

After a 3-month baseline period of data collection, 15 units were randomly assigned to the intervention arm (with performance feedback, small-group teaching seminars, and posters) and 15 units to usual practice. Hand hygiene was observed during randomly selected 15-minute periods on each unit, and the incidence of MRSA colonization was measured using weekly surveillance specimens from June 2007 through May 2008.

We found that 3,812 (48.2%) of 7,901 opportunities for hand hygiene in the intervention group resulted in adherence, compared with 3,205 (42.6%) of 7,526 opportunities in the control group (P < .001; independent t test). There was no reduction in the incidence of hospital-acquired MRSA colonization in the intervention group.

Among HCWs in Ontario tertiary care hospitals, the rate of adherence to hand hygiene had a statistically significant increase of 6% with a multifaceted intervention, but the incidence of MRSA colonization was not reduced.

To determine blood culture contamination rates after skin antisepsis with Chlorhexidine, compared with povidone-iodine.

Retrospective, quasi-experimental study.

Emergency department of a tertiary care children's hospital.

Children aged 2-36 months with peripheral blood culture results from February 2004 to June 2008. Control patients were children younger than 2 months with peripheral blood culture results.

Blood culture contamination rates were compared using segmented regression analysis of time-series data among 3 patient groups: (1) patients aged 2-36 months during the 26-month preintervention period, in which 10% povidone-iodine was used for skin antisepsis before blood culture; (2) patients aged 2-36 months during the 26-month postintervention period, in which 3% Chlorhexidine gluconate was used; and (3) patients younger than 2 months not exposed to the Chlorhexidine intervention (ie, the control group).

Results from 11,595 eligible blood cultures were reviewed (4,942 from the preintervention group, 4,274 from the postintervention group, and 2,379 from the control group). For children aged 2-36 months, the blood culture contamination rate decreased from 24.81 to 17.19 contaminated cultures per 1,000 cultures (P < .05) after implementation of Chlorhexidine. This decrease of 7.62 contaminated cultures per 1,000 cultures (95% confidence interval, —0.781 to —15.16) represented a 30% relative decrease from the preintervention period and was sustained over the entire postintervention period. No change in contamination rate was observed in the control group (P = .337).

Skin antisepsis with Chlorhexidine significantly reduces the blood culture contamination rate among young children, as compared with povidone-iodine.

Surgical site infection (SSI) after coronary artery bypass graft (CABG) surgery is an increasing healthcare problem. Investigators from Australia proposed a new, 3-point scale that assesses SSI risk on the basis of diagnosis of diabetes mellitus and body mass index.

To validate the Australian Clinical Risk Index among patients undergoing CABG surgery in the United States.

Nested case-control study involving patients undergoing CABG surgery at 9 hospitals during 1991-2002.

Case patients were those who developed SSIs after CABG surgery. Control subjects were matched to case patients on the basis of hospital, age, and procedure date.

Odds ratios (ORs) for SSIs were calculated for the comparison of case patients with control subjects for all risk categories determined using the Australian Clinical Risk Index and National Nosocomial Infections Surveillance System (NNIS) risk index. An adjusted area under the curve was used to compare predictive values among risk indices.

Four hundred sixty patients were studied, including 269 patients with SSI and 191 control subjects. NNIS risk group 2 was associated with increased rate of SSI (OR, 1.79; 95% confidence interval [CI], 1.19-2.67). No patient had an NNIS risk index of 3. The remaining NNIS categories were not predictive of infection. In contrast, an increase in Australian Clinical Risk Index was associated with an increase in risk of SSI (category 2: OR, 2.39 [95% CI, 1.33-4.29]; category 3: OR, 4.46 [95% CI, 1.83-10.85]).

The NNIS risk index predicts the risk of SSI associated with many procedures, but it has limited use in predicting the risk of SSI after CABG surgery. The new Australian Clinical Risk Index stratified patients into discrete groups associated with increased risk of SSI. Data from our study support the use of this new risk index in the US population.

To characterize the clinical outcomes of patients with bloodstream infection caused by carbapenem-resistant Acinetobacter baumannii during a 2-state monoclonal outbreak.

Multicenter observational study.

Four tertiary care hospitals and 1 long-term acute care hospital.

A retrospective medical chart review was conducted for all consecutive patients during the period January 1, 2005, through April 30, 2006, for whom 1 or more blood cultures yielded carbapenem-resistant A. baumannii.

We identified 86 patients from the 16-month study period. Their mortality rate was 41%; of the 35 patients who died, one-third (13) had positive blood culture results for carbapenem-resistant A. baumannii at the time of death. Risk factors associated with mortality were intensive care unit stay, malignancy, and presence of fever and/or hypotension at the time blood sample for culture was obtained. Only 5 patients received adequate empirical antibiotic treatment, but the choice of treatment did not affect mortality.

Fifty-seven patients (66.2%) had a single positive blood culture result for carbapenem-resistant A. baumannii; the only factor associated with a single positive blood culture result was the presence of decubitus ulcers. Interestingly, during the study period, a transition from single to multiple positive blood culture results was observed. Four patients, 3 of whom were in a burn intensive care unit, were bacteremic for more than 30 days (range, 36–86 days).

To our knowledge, this is the first time a study has described 2 patterns of bloodstream infection with A. baumannii: single versus multiple positive blood culture results, as well as a subset of patients with prolonged bacteremia.