In April 2009, 2009 pandemic influenza A (H1N1) (hereafter, pH1N1) virus was identified in California, which caused widespread illness throughout the United States. We evaluated pH1N1 transmission among exposed healthcare personnel (HCP) and assessed the use and effectiveness of personal protective equipment (PPE) early in the outbreak.

Cohort study.

Two hospitals and 1 outpatient clinic in Southern California during March 28-April 24, 2009.

Sixty-three HCP exposed to 6 of the first 8 cases of laboratory-confirmed pH1N1 in the United States.

Baseline and follow-up questionnaires were used to collect demographic, epidemiologic, and clinical data. Paired serum samples were obtained to test for pH1N1-specific antibodies by microneutralization and hemagglutination-inhibition assays. Serology results were compared with HCP work setting, role, and self-reported PPE use.

Possible healthcare-associated pH1N1 transmission was identified in 9 (14%) of 63 exposed HCP; 6 (67%) of 9 seropositive HCP had asymptomatic infection. The highest attack rates occurred among outpatient HCP (6/19 [32%]) and among allied health staff (eg, technicians; 8/33 [24%]). Use of mask or N95 respirator was associated with remaining seronegative (P = .047). Adherence to PPE recommendations for preventing transmission of influenza virus and other respiratory pathogens was inadequate, particularly in outpatient settings.

pH1N1 transmission likely occurred in healthcare settings early in the pandemic associated with inadequate PPE use. Organizational support for a comprehensive approach to infectious hazards, including infection prevention training for inpatient- and outpatient-based HCP, is essential to improve HCP and patient safety.

To devise a local strategy for eradication of a hospital-wide outbreak caused by carbapenem-resistant Klebsiella pneumoniae (CRKP).

Quasi-experimental, before-and-after, interrupted time-series study.

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

Retrospectively, all relevant data were collected from the medical records of patients with CRKP infections from May 2006 through April 2007, the preintervention period. From May 1, 2007, through May 1, 2010, the postintervention period, the intervention was applied and prospectively followed. The 5 key elements of this strategy were an emergency department flagging system, the building of a cohort ward, the eradication of clusters, environmental and personnel hand cultures, and a carbapenem-restriction policy. The demographic and clinical parameters of patients colonized by and/or infected with CRKP were collected from medical records.

A total of 10,680 rectal cultures were performed for 8,376 patients; 433 (5.16%) and 370 (4.4%) were CRKP-colonized and CRKP-infected patients, respectively, and 789 (98%) of 803 patients were admitted to the CRKP cohort ward. The CRKP infection density was reduced from 5.26 to 0.18 per 10,000 patient-days (P<.001), and no nosocomial CRKP infections were diagnosed. Twenty-three percent of environmental cultures were found to be positive. Meropenem use was reduced from 283 ± 70.92 to 118 ± 74.32 defined daily doses per 1,000 patient-days (P<.001).

This intervention produced an enormous impact on patient location, surveillance cultures, and antibiotic policies and a massive investment in infection control resources.

Multidrug-resistant Acinetobacter baumannii (MDRAB) is difficult to treat and eradicate. Several reports describe isolation and environmental cleaning strategies that controlled hospital MDRAB outbreaks. Such interventions were insufficient to interrupt MDRAB transmission in 2 intensive care unit-based outbreaks in our hospital. We describe strategies that were associated with termination of MDRAB outbreaks at the National Institutes of Health Clinical Center.

In response to MDRAB outbreaks in 2007 and 2009, we implemented multiple interventions, including stakeholder meetings, enhanced isolation precautions, active microbial surveillance, cohorting, and extensive environmental cleaning. We conducted a case-control study to analyze risk factors for acquiring MDRAB. In each outbreak, infection control adherence monitors were placed in MDRAB cohort areas to observe and correct staff infection control behavior.

Between May 2007 and December 2009, 63 patients acquired nosocomial MDRAB; 57 (90%) acquired 1 or more of 4 outbreak strains. Of 347 environmental cultures, only 2 grew outbreak strains of MDRAB from areas other than MDRAB patient rooms. Adherence monitors recorded 1,330 isolation room entries in 2007, of which 8% required interventions. In 2009, around-the-clock monitors recorded 4,892 staff observations, including 127 (2.6%) instances of nonadherence with precautions, requiring 68 interventions (1.4%). Physicians were responsible for more violations than other staff (58% of hand hygiene violations and 37% of violations relating to gown and glove use). Each outbreak terminated in temporal association with initiation of adherence monitoring.

Although labor intensive, adherence monitoring may be useful as part of a multifaceted strategy to limit nosocomial transmission of MDRAB.

In November 2009, routine sampling of endoscopes performed to monitor the effectiveness of the endoscope-cleaning procedure at our hospital detected Pseudomonas aeruginosa. Herein we report the results of the subsequent investigation.

The investigation included environmental cultures for source investigation, molecular analysis by pulsed-field gel electrophoresis (PFGE) to reveal the identity of the strains, and determination of the bactericidal activity of the glutaraldehyde-based disinfectant used for automated endoscope reprocessing. In addition, patient outcome was analyzed by medical chart review, and incidence rates of clinical samples with P. aeruginosa were compared.

The University Hospital of Basel is an 855-bed tertiary care center in Basel, Switzerland. Approximately 1,700 flexible bronchoscopic, 2,500 gastroscopic, 1,400 colonoscopic, 140 endoscopic retrograde cholangiopancreatographic, and 140 endosonographic procedures are performed annually.

P. aeruginosa was detected in samples obtained from endoscopes in November 2009 for the first time since the initiation of surveillance in 2006. It was found in the rinsing water and in the drain of 1 of the 2 automated endoscope reprocessors. PFGE revealed 2 distinct P. aeruginosa strains, one in each reprocessor. The glutaraldehyde-based disinfectant showed no activity against the 2 pseudo-outbreak strains when used in the recommended concentration under standard conditions. After medical chart review, 6 patients with lower respiratory tract and bloodstream infections were identified as having a possible epidemiological link to the pseudo-outbreak strain.

This is the first description of a pseudo-outbreak caused by P. aeruginosa with reduced susceptibility to an aldehyde-based disinfectant routinely used in the automated processing of endoscopes.

Seven organ/space surgical site infections (SSIs) that occurred after arthroscopic procedures and were due to Pseudomonas aeruginosa of indistinguishable pulsed-field gel electrophoresis (PFGE) patterns occurred at hospital X in Texas from April 22, 2009, through May 7, 2009.

To determine the source of the outbreak and prevent future infections.

Infection control observations and a case-control study.

Laboratory records were reviewed for case finding. A case-control study was conducted. A case patient was defined as someone who underwent knee or shoulder arthroscopy at hospital X during the outbreak period and subsequently developed organ/space SSI due toP. aeruginosa. Cultures of environmental and surgical equipment samples were performed, and selected isolates were analyzed by PFGE. Surgical instrument reprocessing practices were reviewed, and surgical instrument lumens were inspected with a borescope after reprocessing to assess cleanliness.

The case-control study did not identify any significant patient-related or operator-related risk factors. P. aeruginosa grew from 62 of 388 environmental samples. An isolate from the gross decontamination sink had a PFGE pattern that was indistinguishable from that of the case patient isolates. All surgical instrument cultures showed no growth. Endoscopic evaluation of reprocessed arthroscopic equipment revealed retained tissue in the lumen of both the inflow/outflow cannulae and arthroscopic shaver handpiece. No additional cases occurred after changes in instrument reprocessing protocols were implemented. After this outbreak, the US Food and Drug Administration released a safety alert about the concern regarding retained tissue within arthroscopic shavers.

These SSIs were likely related to surgical instrument contamination with P. aeruginosa during instrument reprocessing. Retained tissue in inflow/outflow cannulae and shaver handpieces could have allowed bacteria to survive sterilization procedures.

To compare fluorescent markers with aerobic colony counts (ACCs) and an adenosine triphosphate (ATP) bioluminescence assay system for assessing terminal cleaning practices.

A prospective observational survey.

A 500-bed university-affiliated community teaching hospital.

In a convenience sample of 100 hospital rooms, 5 high-touch surfaces were marked with fluorescent markers before terminal cleaning and checked after cleaning to see whether the marker had been entirely or partially removed. ACC and ATP readings were performed on the same surfaces before and after terminal cleaning.

Overall, 378 (76%) of 500 surfaces were classified as having been cleaned according to fluorescent markers, compared with 384 (77%) according to ACC criteria and 225 (45%) according to ATP criteria. Of 382 surfaces classified as not clean according to ATP criteria before terminal cleaning, those with the marker removed were significantly more likely than those with the marker partially removed to be classified as clean according to ATP criteria (P = .003).

Fluorescent markers are useful in determining how frequently high-touch surfaces are wiped during terminal cleaning. However, contaminated surfaces classified as clean according to fluorescent marker criteria after terminal cleaning were significantly less likely to be classified as clean according to ACC and ATP assays.

Wearing of gloves reduces transmission of organisms by healthcare workers' hands but is not a substitute for hand hygiene. Results of previous studies have varied as to whether hand hygiene is worse when gloves are worn. Most studies have been small and used nonstandardized assessments of glove use and hand hygiene. We sought to observe whether gloves were worn when appropriate and whether hand hygiene compliance differed when gloves were worn.

Observational study.

Healthcare workers in 56 medical or care of the elderly wards and intensive care units in 15 hospitals across England and Wales.

We observed hand hygiene and glove usage (7,578 moments for hand hygiene) during 249 one-hour sessions. Observers also recorded whether gloves were or were not worn for individual contacts.

Gloves were used in 1,983 (26.2%) of the 7,578 moments for hand hygiene and in 551 (16.7%) of 3,292 low-risk contacts; gloves were not used in 141 (21.1%) of 669 high-risk contacts. The rate of hand hygiene compliance with glove use was 41.4% (415 of 1,002 moments), and the rate without glove use was 50.0% (1,344 of 2,686 moments). After adjusting for ward, healthcare worker type, contact risk level, and whether the hand hygiene opportunity occurred before or after a patient contact, glove use was strongly associated with lower levels of hand hygiene (adjusted odds ratio, 0.65 [95% confidence interval, 0.54-0.79]; P<.0001).

The rate of glove usage is lower than previously reported. Gloves are often worn when not indicated and vice versa. The rate of compliance with hand hygiene was significantly lower when gloves were worn. Hand hygiene campaigns should consider placing greater emphasis on the World Health Organization indications for gloving and associated hand hygiene.

National Research Register N0256159318.

Describe central line-associated bloodstream infection (CLA-BSI) epidemiology in pediatric intensive care units (PICUs).

Descriptive study (29 PICUs); cohort study (18 PICUs).

PICUs in a national improvement collaborative.

Patients admitted October 2006 to December 2007 with 1 or more central lines.

CLA-BSIs were prospectively identified using the National Healthcare Safety Network definition and then readjudicated using the revised 2008 definition. Risk factors for CLA-BSI were examined using age-adjusted, time-varying Cox proportional hazards models.

In the descriptive study, the CLA-BSI incidence was 3.1/1,000 central line-days; readjudication with the revised definition resulted in a 17% decrease. In the cohort study, the readjudicated incidence was 2.0/1,000 central line-days. Ninety-nine percent of patients were CLA-BSI-free through day 7, after which the daily risk of CLA-BSI doubled to 0.27% per day. Compared with patients with respiratory diagnoses (most prevalent category), CLA-BSI risk was higher in patients with gastrointestinal diagnoses (hazard ratio [HR], 2.7 [95% confidence interval {CI}, 1.43-5.16]; P<.002) and oncologic diagnoses (HR, 2.6 [CI, 1.06-6.45]; P=.037). Among all patients, including those with more than 1 central line, CLA-BSI risk was lower among patients with a central line inserted in the jugular vein (HR, 0.43 [CI, 0.30-0.95]; P<.03).

The 2008 CLA-BSI definition change decreased the measured incidence. The daily CLA-BSI risk was very low in patients during the first 7 days of catheterization but doubled thereafter. The risk of CLA-BSI was lower in patients with lines inserted in the jugular vein and higher in patients with gastrointestinal and oncologic diagnoses. These patients are target populations for additional study and intervention.