To determine whether copper incorporated into hospital ward furnishings and equipment can reduce their surface microbial load.

A crossover study.

Acute care medical ward with 19 beds at a large university hospital.

Fourteen types of frequent-touch items made of copper alloy were installed in various locations on an acute care medical ward. These included door handles and push plates, toilet seats and flush handles, grab rails, light switches and pull cord toggles, sockets, overbed tables, dressing trolleys, commodes, taps, and sink fittings. Their surfaces and those of equivalent standard items on the same ward were sampled once weekly for 24 weeks. The copper and standard items were switched over after 12 weeks of sampling to reduce bias in usage patterns. The total aerobic microbial counts and the presence of indicator microorganisms were determined.

Eight of the 14 copper item types had microbial counts on their surfaces that were significantly lower than counts on standard materials. The other 6 copper item types had reduced microbial numbers on their surfaces, compared with microbial counts on standard items, but the reduction did not reach statistical significance. Indicator microorganisms were recovered from both types of surfaces; however, significantly fewer copper surfaces were contaminated with vancomycin-resistant enterococci, methicillin-susceptible Staphylococcus aureus, and coliforms, compared with standard surfaces.

Copper alloys (greater than or equal to 58% copper), when incorporated into various hospital furnishings and fittings, reduce the surface microorganisms. The use of copper in combination with optimal infection-prevention strategies may therefore further reduce the risk that patients will acquire infection in healthcare environments.

Infect Control Hosp Epidemiol 2012;33(1):3-9

Hospitalized patients are at increased risk for acquisition of methicillin-resistant Staphylococcus aureus (MRSA). As hospital length of stay shortens, hospital-acquired MRSA events may be more likely to be detected after discharge.

We assessed the impact of attributing MRSA cases discovered within 30 days after discharge to the most recent hospitalization and identified patient characteristics associated with MRSA detection after discharge.

Retrospective cohort study.

Twenty-seven acute care hospitals in Orange County, California.

Adult acute care admissions (2002–2007).

Using a countywide hospital data set containing diagnostic codes with present-on-admission (POA) indicators, we identified the first admission with a MRSA code for each patient. This incident MRSA admission was defined as predischarge-detected (pre-DD) hospital-onset MRSA (HO-MRSA) when MRSA was not POA. If MRSA was POA and a prior admission occurred within 30 days, this prior admission was assigned postdischarge-detected (post-DD) HO-MRSA. We evaluated the impact of including post-DD HO-MRSA in the calculation of hospital HO-MRSA incidence using signed-rank tests and reviewed changes in hospital rankings. We conducted multivariate comparisons of patient characteristics of pre-DD versus post-DD HO-MRSA patients.

Among 1,217,253 at-risk hospitalizations, the inclusion of post-DD HO-MRSA tripled the median hospital HO-MRSA incidence, from 12.2 to 35.7 cases per 10,000 at-risk admissions (P<.0001). Hospital ranking changed substantially when including post-DD HO-MRSA. Patients with shorter stays were more likely to have post-DD MRSA.

On the basis of administrative claims data, the inclusion of post-DD HO-MRSA significantly increased the estimated HO-MRSA incidence and altered hospital rankings. This finding underscores the limitations of single-facility data when deriving HO-MRSA incidence and rank.

Infect Control Hosp Epidemiol 2012;33(2):114-121

To describe rates and pathogen distribution of device-associated infections (DAIs) in neonatal intensive care unit (NICU) patients and compare differences in infection rates by hospital type (children's vs general hospitals).

Neonates in NICUs participating in the National Healthcare Safety Network from 2006 through 2008.

We analyzed central line–associated bloodstream infections (CLABSIs), umbilical catheter–associated bloodstream infections (UCABs), and ventilator-associated pneumonia (VAP) among 304 NICUs. Differences in pooled mean incidence rates were examined using Poisson regression; nonparametric tests for comparing medians and rate distributions were used.

Pooled mean incidence rates by birth weight category (750 g or less, 751–1,000 g, 1,001–1,500 g, 1,501–2,500 g, and more than 2,500 g, respectively) were 3.94, 3.09, 2.25, 1.90, and 1.60 for CLABSI; 4.52, 2.77, 1.70, 0.91, and 0.92 for UCAB; and 2.36, 2.08, 1.28, 0.86, and 0.72 for VAP. When rates of infection between hospital types were compared, only pooled mean VAP rates were significantly lower in children's hospitals than in general hospitals among neonates weighing 1,000 g or less; no significant differences in medians or rate distributions were noted. Pathogen frequencies were coagulase-negative staphylococci (28%), Staphylococcus aureus (19%), and Candida species (13%) for bloodstream infections and Pseudomonas species (16%), S. aureus (15%), and Klebsiella species (14%) for VAP. Of 673 S. aureus isolates with susceptibility results, 33% were methicillin resistant.

Neonates weighing 750 g or less had the highest DAI incidence. With the exception of VAP, pooled mean NICU incidence rates did not differ between children's and general hospitals. Pathogens associated with these infections can pose treatment challenges; continued efforts at prevention need to be applied to all NICU settings.

Privacy curtains that separate patient care areas in hospitals may play an important role in the transmission of healthcare-associated pathogens. The aim of this randomized, controlled trial was to assess the effectiveness in a clinical setting of curtains incorporating a complex element compound (CEC) with antimicrobial properties.

Twenty-one rooms in a surgical intensive care unit (ICU) and 9 rooms in a medical ICU were randomly selected to receive either a new standard curtain or a new identical-looking CEC curtain. Fifteen rooms received CEC curtains and 15 received standard curtains.

Cultures were performed of samples that were collected from curtains twice a week for 4 weeks (23 days). Contamination was determined according to standard microbiologic methods. Time to contamination was assessed with the Wilcoxon rank-sum test and survival analysis. Incidence rates of contamination were compared using Poisson regression.

The median time to first contamination was 7 times longer for CEC curtains than for standard curtains (14 vs 2 days; P< .01). CEC curtains were significantly less contaminated than standard curtains according to earlier culture results but not significantly different for later culture results. Fourteen CEC curtains and 13 standard curtains were contaminated at least once (P = 1.0). The adjusted rate of contamination was 29% lower among CEC versus standard curtains, but this was not statistically significant (rate ratio, 0.71; 95% CI, 0.48–1.07).

CEC privacy curtains increase the time to first contamination as compared with standard curtains. Use of privacy curtains with antimicrobial properties could increase the time between washings and may potentially play a role in decreasing pathogen transmission.

Peripheral venous catheters (PVCs) can be associated with serious infectious complications. We evaluated the effect of education and feedback on process measures to improve PVC care and infectious complications.

Quasi-experimental controlled crossover study with sampling before and after education.

An 804-bed tertiary care teaching hospital.

Nurses and patients in 10 non-intensive care units.

We implemented a process to improve PVC care in 10 non-intensive care units. The 4 periods (each 3 months in duration) included a preintervention period and a staggered educational intervention among nurses. During intervention period 1, 5 units participated in the intervention (group A), and 5 units served as a control group (group B). Group B underwent the intervention during intervention period 2, and both groups A and B received feedback on performance during intervention period 3. Process measures were evaluated twice monthly, and feedback was given to nurses directly and to the unit manager on a monthly basis.

During the preintervention period, there were no significant differences between groups A and B. Of 4,904 intravascular catheters evaluated, 4,434 (90.4%) were peripheral. By the end of the study, there were significant improvements in processes, compared with the preintervention period, including accurate documentation of dressing (from 442 cases [38%] to 718 cases [59%]; P<.0001), catheter dressing being intact (from 968 cases [88.5%] to 1,024 cases [95.2%]; P<.0001), and correct demonstration of scrubbing the hub before infusion (from 161 demonstrations [54%] to 316 demonstrations [95%]; P <.0001). There was a significant reduction in PVC-associated bloodstream infection, from 2.2 cases per 10,000 patient-days during the preintervention period (5 cases) to 0.44 cases per 10,000 patient days during the 3 intervention periods (3 cases; P = .016).

Education and real-time feedback to nurses increases and sustains compliance with processes to reduce the risk of infection from PVCs.

The goal of this study was to develop a prognostic scoring system for the development of prosthetic joint infection (PJI) that could risk-stratify patients undergoing total hip (THA) or total knee (TKA) arthroplasties.

Previously reported case-control study.

Tertiary referral care setting from 2001 through 2006.

A derivation data set of 339 cases and 339 controls was used to develop 2 scores. A baseline score and a 1-month-postsurgery risk score were computed as a function of the relative contributions of risk factors for each model. Points were assigned for the presence of each factor and then summed to get a subject's risk score.

The following risk factors were detected from multivariable modeling and incorporated into the baseline Mayo PJI risk score: body mass index, prior other operation on the index joint, prior arthroplasty, immunosuppression, ASA score, and procedure duration (c index, 0.722). The 1-month-postsurgery risk score contained the same variables in addition to postoperative wound drainage (c index, 0.716).

The baseline score might help with risk stratification in relation to public reporting and reimbursement as well as targeted prevention strategies in patients undergoing THA or TKA. The application of the 1-month-postsurgery PJI risk score to patients undergoing THA or TKA might benefit those undergoing workup for PJI.

Define optimum vascular catheter connector valve disinfection practices under laboratory and clinical conditions.

Prospective observational clinical survey and laboratory assessment of disinfection procedures.

All adult inpatients at an academic healthcare center.

In the clinical setting, contamination of needleless connectors was assessed in 6 weekly prevalence surveys in which the connector valves from central venous catheters (CVCs) in situ were cultured by pressing the connector diaphragm to an agar plate. Before culture, valves were disinfected by scrubbing the diaphragm with a 70% isopropyl alcohol pledget for 0, 5, 10, 15, or 30 seconds. In the laboratory, the diaphragms on 150 unused sterile connector valves were inoculated with 103, 105, or 108 colony-forming units of Staphylococcus epidermidis and allowed to dry. After disinfection of the diaphragms by scrubbing with a 70% isopropyl alcohol pledget for 0, 5, 10, 15, or 30 seconds, the valves were sampled by pressing the diaphragm to an agar plate.

In the clinical setting, 363 connector valves from patients with CVCs were sampled, and 66.7% of nondisinfected valves revealed bacterial contamination. After 5-second disinfection with an alcohol pledget, only 1 (1.4%) of 71 yielded microbial growth (P < .005). In the laboratory, at the 103 and 105 inoculum, all connector valves yielded sterile cultures when scrubbed for 5 or more seconds (P < .001). At the 108 inoculum, 2 (20%) of 10 connector valves yielded minimal growth of S. epidermidis.

A 5-second scrub with a 70% isopropyl alcohol pledget yields adequate disinfection of a split-septum intravascular catheter connector valve under clinical and laboratory conditions.

To identify risk factors associated with methicillin-resistant Staphylococcus aureus (MRSA) acquisition in long-term care facility (LTCF) residents.

Multicenter, prospective cohort followed over 6 months.

Three Veterans Affairs (VA) LTCFs.

All current and new residents except those with short stay (<2 weeks).

MRSA carriage was assessed by serial nares cultures and classified into 3 groups: persistent (all cultures positive), intermittent (at least 1 but not all cultures positive), and noncarrier (no cultures positive). MRSA acquisition was defined by an initial negative culture followed by more than 2 positive cultures with no subsequent negative cultures. Epidemiologic data were collected to identify risk factors, and MRSA isolates were typed by pulsed-field gel electrophoresis (PFGE).

Among 412 residents at 3 LTCFs, overall MRSA prevalence was 58%, with similar distributions of carriage at all 3 facilities: 20% persistent, 39% intermittent, 41% noncarriers. Of 254 residents with an initial negative swab, 25 (10%) acquired MRSA over the 6 months; rates were similar at all 3 LTCFs, with no clusters evident. Multivariable analysis demonstrated that receipt of systemic antimicrobials during the study was the only significant risk factor for MRSA acquisition (odds ratio, 7.8 [95% confidence interval, 2.1–28.6]; P = .002). MRSA strains from acquisitions were related by PFGE to those from a roommate in 9/25 (36%) cases; 6 of these 9 roommate sources were persistent carriers.

MRSA colonization prevalence was high at 3 separate VA LTCFs. MRSA acquisition was strongly associated with antimicrobial exposure. Roommate sources were often persistent carriers, but transmission from roommates accounted for only approximately one-third of MRSA acquisitions.

The diagnosis of central line-associated bloodstream infections (CLABSIs) is often controversial, and existing guidelines differ in important ways.

To determine both the range of practices involved in obtaining blood culture samples and how central line-associated infections are diagnosed and to obtain members' opinions regarding the process of designating bloodstream infections as publicly reportable CLABSIs.

Electronic and paper 11-question survey of infectious-diseases physician members of the Infectious Diseases Society of America Emerging Infections Network (IDSA EIN).

All 1,364 IDSA EIN members were invited to participate.

692 (51%) members responded; 52% of respondents with adult practices reported that more than half of the blood culture samples for intensive care unit (ICU) patients with central lines were drawn through existing lines. A sizable majority of respondents used time to positivity, differential time to positivity when paired blood cultures are used, and quantitative culture of catheter tips when diagnosing CLABSI or determining the source of that bacteremia. When determining whether a bacteremia met the reportable CLABSI definition, a majority used a decision method that involved clinical judgment.

Our survey documents a strong preference for drawing 1 set of blood culture samples from a peripheral line and 1 from the central line when evaluating fever in an ICU patient, as recommended by IDSA guidelines and in contrast to current Centers for Disease Control and Prevention recommendations. Our data show substantial variability when infectious-diseases physicians were asked to determine whether bloodstream infections were primary bacteremias, and therefore subject to public reporting by National Healthcare Safety Network guidelines, or secondary bacteremias, which are not reportable.

To describe a pseudo-outbreak associated with loose bronchoscope biopsy ports caused by inadequate bronchoscope repair practices by third-party vendors and to alert healthcare personnel to assess bronchoscope repair practices.

Outbreak investigation.

A 925-bed tertiary care hospital in Baltimore, Maryland.

Patients who underwent bronchoscopy with certain bronchoscopes after they had been repaired by a third-party vendor.

An epidemiologic investigation was conducted to determine the cause of Pseudomonas putida growth in 4 bronchoalveolar lavage (BAL) specimens within a 3-day period in May 2008. All bronchoscopes were inspected, and cultures were obtained from bronchoscopes and the environment. Bronchoscope cleaning and maintenance practices were reviewed. Microbiologic results from BAL specimens and medical records were reviewed to find additional cases.

All 4 case patients had undergone bronchoscopy with one of 2 bronchoscopes, both of which had loose biopsy ports. Bronchoscope cultures grew P. putida, Pseudomonas aeruginosa, and Stenotrophomonas. The P. putida strains from the bronchoscopes matched those from the patients. Specimens from 12 additional patients who underwent bronchoscopy with these bronchoscopes grew P. putida, P. aeruginosa, or Stenotrophomonas. No patients developed clinical signs or symptoms of infection, but 7 were treated with antibiotics. Investigation revealed that the implicated bronchoscopes had been sent to an external vendor for repair; examination by the manufacturer revealed irregularities in repairs and nonstandard part replacements.

Third-party vendors without access to proprietary information may contribute to mechanical malfunction of medical devices, which can lead to contamination and incomplete disinfection.

Infect Control Hosp Epidemiol 2012;33(3):224-229

The incidence of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in the United States decreased during 2005–2008, but noninvasive community-associated MRSA (CA-MRSA) infections also frequently lead to hospitalization. We estimated the incidence of all MRSA infections among inpatients at US academic medical centers (AMCs) per 1,000 admissions during 2003–2008.

Retrospective cohort study.

Hospitalized patients at 90% of nonprofit US AMCs during 2003–2008.

Administrative data on MRSA infections from a hospital discharge database (University HealthSystem Consortium [UHC]) were adjusted for underreporting of the MRSA V09.0 International Classification of Diseases, Ninth Revision, Clinical Modification code and validated using chart reviews for patients with known MRSA infections in 2004–2005, 2006, and 2007.

The mean sensitivity of administrative data for MRSA infections at the University of Chicago Medical Center in three 12-month periods during 2004–2007 was 59.1%. On the basis of estimates of billing data sensitivity from the literature and the University of Chicago Medical Center, the number of MRSA infections per 1,000 hospital discharges at US AMCs increased from 20.9 (range, 11.1–47.7) in 2003 to 41.7 (range, 21.9–94.0) in 2008. At the University of Chicago Medical Center, among infections cultured more than 3 days prior to hospital discharge, CA-MRSA infections were more likely to be captured in the UHC billing-derived data than were healthcare-associated MRSA infections.

The number of hospital admissions for any MRSA infection per 1,000 hospital admissions overall increased during 2003–2008. Use of unadjusted administrative hospital discharge data or surveillance for invasive disease far underestimates the number of MRSA infections among hospitalized patients.

To assess the effectiveness of selective digestive decontamination (SDD) for eradicating carbapenem-resistant Klebsiella pneumoniae (CRKP) oropharyngeal and gastrointestinal carriage.

A randomized, double-blind, placebo-controlled trial with 7 weeks of follow-up per patient.

A 1,000-bed tertiary-care university hospital.

Adults with CRKP-positive rectal swab cultures.

Patients were blindly randomized (1:1) over a 20-month period. The SDD arm received oral gentamicin and polymyxin E gel (0.5 g 4 times per day) and oral solutions of gentamicin (80 mg 4 times per day) and polymyxin E (1 × 106 units 4 times per day for 7 days). The placebo arm received oral placebo gel 4 times per day and 2 placebo oral solutions 4 times per day for 7 days. Strict contact precautions were applied. Samples obtained from the throat, groin, and urine were also cultured.

Forty patients (mean age ± standard deviation, 71 ± 16 years; 65% male) were included. At screening, greater than or equal to 30% of oropharyngeal, greater than or equal to 60% of skin, and greater than or equal to 35% of urine cultures yielded CRKP isolates. All throat cultures became negative in the SDD arm after 3 days (P< .0001). The percentages of rectal cultures that were positive for CRKP were significandy reduced at 2 weeks. At that time, 16.1% of rectal cultures in the placebo arm and 61.1% in the SDD arm were negative (odds ratio, 0.13; 95% confidence interval, 0.02–0.74; P<.0016). A difference between the percentages in the 2 arms was still maintained at 6 weeks (33.3% vs 58.5%). Groin colonization prevalence did not change in either arm, and the prevalence of urine colonization increased in the placebo arm.

This SDD regimen could be a suitable decolonization therapy for selected patients colonized with CRKP, such as transplant recipients or immunocompromised patients pending chemotherapy and patients who require major intestinal or oropharyngeal surgery. Moreover, in outbreaks caused by CRKP infections that are uncontrolled by routine infection control measures, SDD could provide additional infection containment.

Infect Control Hosp Epidemiol 2012;33(1):14-19