To develop prediction algorithms for the presence of a central vascular catheter in hospitalized patients with use of data present in an electronic health record. Such algorithms could be used for measurement of device utilization rates and for clinical decision support rules.

Criterion standard.

John H. Stroger, Jr, Hospital of Cook County, a 464-bed public hospital in Chicago, Illinois.

Patients admitted to the medical intensive care unit from May 31, 2005 through June 26, 2006 (derivation data set, May 31, 2005-September 28, 2005; validation data set, September 29, 2005-June 28, 2006).

Covariates were collected from the electronic medical record for each patient; the outcome variable was presence of a central vascular device. Multivariate models were developed using the derivation set and the generalized estimating equation. Three models, each with increasing database requirements, were validated using the validation set. Device utilization ratios and performance characteristics were calculated.

Although Charlson score and duration of intensive care unit stay were significant predictors in all models, factors that indicated use or presence of a central line were also important. Device utilization rates derived from the algorithmic models were as accurate as those obtained using manual sampling.

Automated calculation of central vascular catheter use is both feasible and accurate, providing estimates statistically similar to those obtained using manual surveillance. Prediction modeling of central vascular catheter use may enable automated surveillance of bloodstream infections and enhance important prevention interventions, such as timely removal of unnecessary central lines.

To evaluate the effectiveness of a positive deviance strategy for the improvement of hand hygiene compliance in 2 adult step-down units.

A 9-month, controlled trial comparing the effect of positive deviance on compliance with hand hygiene.

Two 20-bed step-down units at a tertiary care private hospital.

The first phase of our study was a 3-month baseline period (from April to June 2008) in which hand hygiene episodes were counted by use of electronic handwashing counters. From July to September 2008 (ie, the second phase), a positive deviance strategy was implemented in the east unit; the west unit was the control unit. During the period from October to December 2008 (ie, the third phase), positive deviance was applied in both units.

During the first phase, there was no statistically significant difference between the 2 step-down units in the number of episodes of hand hygiene per 1,000 patient-days or in the incidence density of healthcare-associated infections (HAIs) per 1,000 patient-days. During the second phase, there were 62,000 hand hygiene episodes per 1,000 patient-days in the east unit and 33,570 hand hygiene episodes per 1,000 patient-days in the west unit (P < .01). The incidence density of HAIs per 1,000 patient-days was 6.5 in the east unit and 12.7 in the west unit (P = .04). During the third phase, there was no statistically significant difference in hand hygiene episodes per 1,000 patient-days (P = .16) or in incidence density of HAIs per 1,000 patient-days.

A positive deviance strategy yielded a significant improvement in hand hygiene, which was associated with a decrease in the overall incidence of HAIs.

Current guidelines for control of Clostridium difficile infection (CDI) suggest that contact precautions be discontinued after diarrhea resolves. However, limited information is available regarding the frequency of skin contamination and environmental shedding of C. difficile during and after treatment.

We conducted a 9-month prospective, observational study involving 52 patients receiving therapy for CDI. Stool samples, skin (chest and abdomen) samples, and samples from environmental sites were cultured for C. difficile before, during, and after treatment. Polymerase chain reaction ribotyping was performed to determine the relatedness of stool, skin, and environmental isolates.

Fifty-two patients with CDI were studied. C. difficile was suppressed to undetectable levels in stool samples from most patients during treatment; however, 1-4 weeks after treatment, 56% of patients who had samples tested were asymptomatic carriers of C. difficile. The frequencies of skin contamination and environmental shedding remained high at the time of resolution of diarrhea (60% and 37%, respectively), were lower at the end of treatment (32% and 14%, respectively), and again increased 1-4 weeks after treatment (58% and 50%, respectively). Skin and environmental contamination after treatment was associated with use of antibiotics for non-CDI indications. Ninety-four percent of skin isolates and 82% of environmental isolates were genetically identical to concurrent stool isolates.

Skin contamination and environmental shedding of C. difficile often persist at the time of resolution of diarrhea, and recurrent shedding is common 1-4 weeks after therapy. These results provide support for the recommendation that contact precautions be continued until hospital discharge if rates of CDI remain high despite implementation of standard infection-control measures.

Vancomycin-resistant Enterococcus (VRE) bloodstream infections (BSIs) are associated with increased morbidity and mortality.

To determine the hospital costs and length of stay attributable to VRE BSI and vancomycin-sensitive Enterococcus (VSE) BSI and the independent effect of vancomycin resistance on hospital costs.

A retrospective cohort study was conducted of 21,154 nonsurgical patients admitted to an academic medical center during the period from 2002 through 2003. Using administrative data, attributable hospital costs (adjusted for inflation to 2007 US dollars) and length of stay were estimated with multivariate generalized least-squares (GLS) models and propensity score-matched pairs.

The cohort included 94 patients with VRE BSI and 182 patients with VSE BSI. After adjustment for demographics, comorbidities, procedures, nonenterococcal BSI, and early mortality, the costs attributable to VRE BSI were $4,479 (95% confidence interval [CI], $3,500-$5,732) in the standard GLS model and $4,036 (95% CI, $3,170-$5,140) in the propensity score-weighted GLS model, and the costs attributable to VSE BSI were $2,250 (95% CI, $l,758-$2,880) in the standard GLS model and $2,023 (95% CI, $1,588-$2,575) in the propensity score-weighted GLS model. The median values of the difference in costs between matched pairs were $9,949 (95% CI, $1,579-$24,693) for VRE BSI and $5,282 (95% CI, $2,042-$8,043) for VSE BSI. The costs attributable to vancomycin resistance were $1,713 (95% CI, $1,338-$2,192) in the standard GLS model and $1,546 (95% CI, $1,214-$1,968) in the propensity score-weighted GLS model. Depending on the statistical method used, attributable length of stay estimates ranged from 2.2 to 3.5 days for patients with VRE BSI and from 1.1 to 2.2 days for patients with VSE BSI.

VRE BSI and VSE BSI were independently associated with increased hospital costs and increased length of stay. Vancomycin resistance was associated with increased costs.

Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging concern in infectious disease practice. Although MRSA infections occur in a wide variety of anatomic sites, the majority of studies considering the risk factors for methicillin resistance among S. aureus infections have focused on MRSA bacteremia.

To describe risk factors associated with methicillin resistance among S. aureus infections at different anatomic sites.

We collected information on the demographic and clinical characteristics of patients examined at the Atlanta Veterans Affairs Medical Center with S. aureus infections during the period from June 2007 through May 2008. We used multivariate logistic regression to describe factors significantly associated with methicillin resistance.

There were 568 cases of S. aureus infection among 528 patients. We identified 352 cases (62%) of MRSA infection and 216 cases (38%) of methicillin-sensitive S. aureus infection. The adjusted odds of methicillin resistance were higher among infections that occurred among patients who had a prior history of MRSA infection (odds ratio [OR], 3.9 [95% confidence interval {CI}, 2.3–6.4]) or resided in a long-term care facility during the past 12 months (OR, 2.0 [95% CI, 1.0-4.0]) but were lower for infections that occurred among patients who had undergone a biopsy procedure during the past 12 months (OR, 0.7 [95% CI, 0.6-0.9]). Most cases of infection were community-onset infections (523 [92%] of 568 cases), and about one-half (278 [49%]) were not healthcare associated.

Compared with previous studies of methicillin resistance among patients with S. aureus bacteremia, we found similar factors to be associated with methicillin resistance among S. aureus isolates recovered from more diverse anatomic sites of infection. Of note, nearly one-half of our cases of MRSA infection were not healthcare associated.

To evaluate the prevalence of and risk factors for extranasal methicillin-resistant Staphylococcus aureus (MRSA) colonization and its relationship to nasal colonization among veterans hospitalized for acute care.

Prospective observational study.

Veterans Affairs (VA) acute care hospital in Boston, Massachusetts.

Convenience sample of 150 patients hospitalized within the previous 36 hours and screened for nasal MRSA who were not known to have an active MRSA infection or MRSA isolates recovered from a wound during the past 12 months.

Potential risk factors for MRSA colonization were assessed, and oropharynx, axilla, hand, perirectal, wound, and catheter insertion site samples were obtained for culture. MRSA was identified in chromogenic agar and confirmed by use of routine culture techniques. Nasal MRSA colonization was detected by means of polymerase chain reaction (PCR).

Nasal swab samples analyzed by use of PCR yielded results positive for MRSA in 16 (11%) of 150 patients. Extranasal cultures yielded positive results for 3 (2%) of 134 patients who tested negative for nasal MRSA colonization and for 9 (56%) of 16 patients who tested positive for nasal MRSA colonization (odds ratio [OR], 56.1 [95% confidence interval {CI}, 12.4-254.6]; P <.001). The oropharynx was the most commonly colonized extranasal site (10 patients [7%]). Independent risk factors for extranasal MRSA colonization included nasal MRSA colonization (OR, 66.9 [95% CI, 11.8-379.7]; P <.001) and end-stage hepatic disease (OR, 98.5 [95% CI, 3.1-3,112.4]; P = .01).

Extranasal MRSA colonization is infrequent among veterans admitted for acute care to VA Boston Healthcare System. Extranasal MRSA colonization was strongly associated with nasal MRSA colonization, which suggests that the VA MRSA Prevention Initiative is not missing a large number of MRSA-colonized patients by focusing on nasal-only screening.

Pseudomonas aeruginosa is one of the most common gram-negative hospital-acquired pathogens. Resistance of this organism to imipenem complicates treatment.

To elucidate the risk factors for imipenem-resistant P. aeruginosa (IRPA) infection or colonization and to identify the effect of resistance on clinical and economic outcomes.

Longitudinal trends in prevalence of IRPA from 2 centers were characterized during the period from 1989 through 2006. For P. aeruginosa isolates obtained during the period from 2001 through 2006, a case-control study was conducted to investigate the association between prior carbapenem use and IRPA infection or colonization, and a cohort study was performed to identify the effect of IRPA infection or colonization on mortality, length of stay after culture, and hospital cost after culture.

From 1989 through 2006, the proportion of P. aeruginosa isolates demonstrating resistance to imipenem increased from 13% to 20% (P< .001, trend). During the period from 2001 through 2006, there were 2,542 unique patients with P. aeruginosa isolates, and 253 (10.0%) had IRPA isolates. Prior carbapenem use was independently associated with IRPA infection or colonization (adjusted odds ratio [OR], 7.92 [95% confidence interval {CI}, 4.78-13.11]). Patients with an IRPA isolate recovered had higher in-hospital mortality than did patients with an imipenem-susceptible P. aeruginosa isolate (17.4% vs 13.4%; P = .01). IRPA infection or colonization was an independent risk factor for mortality among patients with isolates recovered from blood (adjusted OR, 5.43 [95% CI, 1.72-17.10]; P = .004) but not among patients with isolates recovered from other anatomic sites (adjusted OR, 0.78 [95% CI, 0.51-1.21]; P = .27). Isolation of IRPA was associated with longer hospital stay after culture (P<.001) and greater hospital cost after culture (P<.001) than was isolation of an imipenem-susceptible strain. In multivariable analysis, IRPA infection or colonization remained an independent risk factor for both longer hospital stay after culture (coefficient, 0.20 [95% CI, 0.04-0.36]; P = .02) and greater hospital cost after culture (coefficient, 0.30 [95% CI, 0.06-0.54]; P = .02).

The prevalence of IRPA infection or colonization has increased significantly, with important implications for both clinical and economic outcomes. Interventions to curb this continued increase and strategies to optimize therapy are urgently needed.

To describe an outbreak of infection associated with an infrequently implicated pathogen, Elizabethkingia meningoseptica, in an increasingly prominent setting for health care of severely ill patients, the long-term acute care hospital.

Outbreak investigation.

Long-term acute care hospital with 55 patients, most of whom were mechanically ventilated.

We defined a case as E. meningoseptica isolated from any patient specimen source from December 2007 through April 2008, conducted an investigation of case patients, obtained environmental specimens, and performed microbiologic testing.

Nineteen patients had E. meningoseptica infection, and 8 died. All case patients had been admitted with respiratory failure that required mechanical ventilation. Among the 8 individuals who died, the time from collection of the first specimen positive for E. meningoseptica to death ranged from 6 to 43 days (median, 16 days). Environmental sampling was performed on 106 surfaces; E. meningoseptica was isolated from only one swab. Three related pulsed-field gel electrophoresis patterns were identified in patient isolates; the environmental isolate yielded a fourth, unrelated pattern.

Long-term acute care hospitals with mechanically ventilated patients could serve as an important transmission setting for E. meningoseptica. This multidrug-resistant bacterium could pose additional risk when patients are transferred between long-term acute care hospitals and acute care hospitals.

To characterize the degree of colonization with multidrug-resistant organisms (MDROs) among patients admitted to a long-term acute care hospital.

Ecologie Study.

A 70-bed long-term acute care hospital (a hospital within a hospital) in the greater Chicago area.

As part of an infection control initiative, specimens were collected from all consecutively admitted patients for culture of MDROs within 72 hours of admission. Cultures from July 28, 2005, through November 1, 2008, were analyzed on the basis of the bodily site from which the isolate was recovered and the organisms identified. If MDROs were yielded by culture of specimens that were obtained from 24 hours to 30 days after collection of the patient's original set of specimens, these MDROs were removed from the analysis. In addition, repeat rectal swab samples were collected for culture at 2 weeks after admission for all consecutive patients admitted from January 1 through March 31, 2007.

A total of 1,739 patients with a total of 5,198 specimens met entry criteria. Of the corresponding 5,198 surveillance cultures, 1,580 (30%) were positive for MDROs. Of the 1,739 patients, 947 (54%) had a culture-positive specimen recovered from any site. Vancomycin-resistant Enterococcus was the organism most commonly isolated in cultures of rectal swab samples (in 38% of such cultures) and wounds (in 18% of such cultures). The rate of rectal carriage of vancomycin-resistant Enterococcus increased from 29% in 2005 to 44% in 2008.

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 determine independent risk factors for endometritis after low transverse cesarean delivery.

We performed a retrospective case-control study during the period from July 1999 through June 2001 in a large tertiary care academic hospital. Endometritis was defined as fever beginning more than 24 hours or continuing for at least 24 hours after delivery plus fundal tenderness in the absence of other causes for fever. Independent risk factors for endometritis were determined by means of multivariable logistic regression. A fractional polynomial method was used to examine risk of endometritis associated with the continuous variable, duration of rupture of membranes.

Endometritis was identified in 124 (7.7%) of 1,605 women within 30 days after low transverse cesarean delivery. Independent risk factors for endometritis included younger age (odds ratio [OR], 0.93 [95% confidence interval {CI}, 0.90-0.97]) and anemia or perioperative blood transfusion (OR, 2.18 [CI, 1.30-3.68] ). Risk of endometritis was marginally associated with a proxy for low socioeconomic status, lack of private health insurance (OR, 1.72 [CI, 0.99-3.00]); with amniotomy (OR, 1.69 [CI, 0.97-2.95]); and with longer duration of rupture of membranes.

Risk of endometritis was independently associated with younger age and anemia and was marginally associated with lack of private health insurance and amniotomy. The odds of endometritis increased approximately 1.7-fold within 1 hour after rupture of membranes, but increased duration of rupture was only marginally associated with increased risk. Knowledge of these risk factors can guide selective use of prophylactic antibiotics during labor and heighten awareness of the risk in subgroups at highest risk of infection.

In patients with smear-positive pulmonary tuberculosis who are hospitalized or reside in congregate settings, guidelines recommend airborne infection isolation until sputum smear results are negative. Studies have identified factors associated with delayed sputum smear and culture conversion in patients with tuberculosis. Because these studies did not use methods of survival analysis, estimates of time to sputum smear conversion that are based on initial patient characteristics are not available. The ability to predict time to sputum smear conversion could be useful for programmatic planning and patient counseling.

We performed a cohort study using survival analysis to identify factors associated with time to sputum smear and culture conversion. We defined the time to sputum smear conversion as the time elapsed from the start of treatment to the first date of sustained conversion.

Ninety-eight patients had sputum smear samples positive for acid-fast bacilli. Lower initial smear grade (on 1+ to 4+ scale) and absence of cavitation on chest radiograph were associated with earlier sputum smear conversion in bivariate analysis. In multiple regression analysis, initial smear grade (hazard ratio, 0.45; 95% confidence interval, 0.35-0.57) and drug resistance (hazard ratio, 2.30; 95% confidence interval, 1.08-4.89) remained statistically significant; a model comprising only initial smear grade performed almost as well. Predictors of sputum culture conversion were similar.

Initial smear grade was the strongest predictor of time to sputum smear and culture conversion in patients with pulmonary tuberculosis and may be a useful predictor for programmatic planning and patient counseling.