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.

Employees of long-term care facilities (LTCFs) who have contact with residents should be vaccinated against influenza annually to reduce influenza incidence among residents. This investigation estimated the magnitude of the benefit of this recommendation.

The New Mexico Department of Health implemented active surveillance in all of its 75 LTCFs during influenza seasons 2006-2007 and 2007-2008. Information about the number of laboratory-confirmed cases of influenza and the proportion vaccinated of both residents and direct-care employees in each facility was collected monthly. LTCFs reporting at least 1 case of influenza (defined alternately by laboratory confirmation or symptoms of influenza-like illness [ILI]) among residents were compared with LTCFs reporting no cases of influenza. Regression modeling was used to obtain adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for the association between employee vaccination coverage and the occurrence of influenza outbreaks. Covariates included vaccination coverage among residents, the staff-to-resident ratio, and the proportion of filled beds.

Seventeen influenza outbreaks were reported during this 2-year period of surveillance. Eleven of these were laboratory confirmed (n = 21 residents) and 6 were defined by ILI (n = 40 residents). Mean influenza vaccination coverage among direct-care employees was 51% in facilities reporting outbreaks and 60% in facilities not reporting outbreaks (P = .12). Increased vaccination coverage among direct-care employees was associated with fewer reported outbreaks of laboratory-confirmed influenza (aOR, 0.97 [95% CI, 0.95-0.99]) and ILI (aOR, 0.98 [95% CI, 0.96-1.00]).

High vaccination coverage among direct-care employees helps to prevent influenza in LTCFs.

Limited data on the risk of peripherally inserted central venous catheter-associated bloodstream infections (PICC BSIs) in hospitalized patients are available. In 2007, dedicated intravenous therapy nurses were no longer available to place difficult peripheral intravenous catheters or provide PICC care Barnes-Jewish Hospital.

To determine the hospital-wide incidence of PICC BSIs and to assess the effect of discontinuing intravenous therapy service on PICC use and PICC BSI rates.

A 1,252-bed tertiary care teaching hospital.

A 31-month retrospective cohort study was performed. PICC BSIs were defined using National Healthcare Safety Network criteria.

In total, 163 PICC BSIs were identified (3.13 BSIs per 1,000 catheter-days). PICC use was higher in intensive care units (ICUs) than non-ICU areas (PICC utilization ratio, 0.109 vs 0.059 catheter-days per patient-day for ICU vs non-ICU; rate ratio [RR], 1.84 [95% confidence interval {CI}, 1.78-1.91]). PICC BSI rates were higher in ICUs (4.79 vs 2.79 episodes per 1,000 catheter-days; RR, 1.7 [95% CI, 1.10-2.61]). PICC use increased hospital-wide after the intravenous therapy service was discontinued (0.049 vs 0.097 catheter-days per patient-day; P = .01), but PICC BSI rates did not change (2.68 vs 3.63 episodes per 1,000 catheter-days; P = .06). Of PICC BSIs, 73% occurred in non-ICU patients.

PICC use and PICC BSI rates were higher in ICUs; however, most of the PICC BSIs occurred in non-ICU areas. Reduction in intravenous therapy services was associated with increased PICC use across the hospital, but PICC BSI rates did not increase.

Central line-associated bloodstream infections (CLABSIs) frequently complicate the use of central venous catheters (CVCs) among pediatric patients with cancer. Our objectives were to describe the microbiology and identify risk factors for hospital-onset CLABSI in this patient population.

Retrospective case-control study.

Oncology and stem cell transplant units of a freestanding, 396-bed quaternary care pediatric hospital.

Case subjects (N = 54) were patients with a diagnosis of malignancy and/or stem cell transplant recipients with CLABSI occurring during admission. Controls (N = 108) were identified using risk set sampling of hospitalizations among patients with a CVC, matched on date of admission.

Multivariate conditional logistic regression was used to identify independent predictors of CLABSI.

The majority of CLABSI isolates were gram-positive bacteria (58%). The most frequently isolated organism was Enterococcus faecium, and 6 of 9 isolates were resistant to vancomycin. In multivariate analyses, independent risk factors for CLABSI included platelet transfusion within the prior week (odds ratio [OR], 10.90 [95% confidence interval (CI), 3.02-39.38]; P<.001) and CVC placement within the previous month (<1 week vs ≥1 month: OR, 11.71 [95% CI, 1.98-69.20]; P = .02; ≥1 week and <1 month vs ≥1 month: OR, 7.37 [95% CI, 1.85-29.36]; P = .004).

Adjunctive measures to prevent CLABSI among pediatric oncology patients may be most beneficial in the month following CVC insertion and in patients requiring frequent platelet transfusions. Vancomycin-resistant enterococci may be an emerging cause of CLABSI in hospitalized pediatric oncology patients and are unlikely to be treated by typical empiric antimicrobial regimens.

To investigate potential sources and risks associated with multidrug-resistant (MDR) bacteria in a deployed US military hospital.

Retrospective analysis of factors associated with recovery of MDR bacteria, supplemented by environmental sampling.

The largest US military hospital in Afghanistan.

US and Afghan patients with positive bacterial culture results, from September 2007 through August 2008.

Microbiologic, demographic, and clinical data were analyzed. Potential risk factors included admission diagnosis or mechanism of injury, length of stay, gender, age, and nationality (US or Afghan). Environmental sampling of selected hospital high-touch surfaces and equipment was performed to help elucidate whether environmental MDR bacteria were contributing to nosocomial spread.

A total of 266 patients had 411 bacterial isolates that were identified during the study period, including 211 MDR bacteria (51%). Gram-negative bacteria were common among Afghan patients (241 [76%] of 319), and 70% of these were classified as MDR. This included 58% of bacteria recovered from Afghan patients within 48 hours of hospital admission. The most common gram-negative bacteria were Escherichia coli (53% were MDR), Acinetobacter (90% were MDR), and Klebsiella (63% were MDR). Almost one-half of potential extended-spectrum β-lactamase (ESBL) producers were community acquired. Of 100 environmental swab samples, 18 yielded MDR bacteria, including 10 that were Acinetobacter, but no potential ESBL-producing bacteria.

Gram-negative bacteria from Afghan patients had high rates of antimicrobial resistance. Patients experiencing Complex trauma and prolonged hospital stays likely contribute to the presence of MDR bacteria in this facility. However, many of these patients had community-acquired cases, which implies high rates of colonization prior to hospital admission.

Recent outbreaks of Clostridium difficile infection (CDI) have been difficult to control, and data indicate that the importance of different sources of transmission may have changed. Our objectives were to evaluate the contributions of asymptomatic and symptomatic C. difficile carriers to new colonizations and to determine the most important epidemiological factors influencing C. difficile transmission.

Retrospective cohort study of all patients admitted to medical wards at a large tertiary care hospital in the United States in the calendar year 2008.

Data from six medical wards and published literature were used to develop a compartmental model of C. difficile transmission. Patients could be in one of five transition states in the model: resistant to colonization (R), susceptible to colonization (S), asymptomatically colonized without protection against CDI (C-), asymptomatically colonized with protection against CDI (C+), and diseased (ie, with CDI; D).

The contributions of C-, C+, and D patients to new colonizations were similar. The simulated basic reproduction number ranged from 0.55 to 1.99, with a median of 1.04. These values suggest that transmission within the ward alone from patients with CDI cannot sustain new C. difficile colonizations and therefore that the admission of colonized patients plays an important role in sustaining transmission in the ward. The epidemiological parameters that ranked as the most influential were the proportion of admitted C- patients and the transmission coefficient for asymptomatic carriers.

Our study underscores the need to further evaluate the role of asymptomatically colonized patients in C. difficile transmission in healthcare settings.

To compare 8 severity score indices for Clostridium difficile infection (CDI).

Prospective observational study.

This study was conducted from July through October 2006. All hospitalized patients in 3 university-affiliated hospitals with a positive fecal Clostridium difficile toxin assay result were evaluated. Infection was considered severe if patients had at least 1 of the following clinical events during their hospitalization: (1) death attributed to CDI within 30 days after diagnosis, (2) colectomy necessitated by CDI, or (3) intensive care unit admission for management of complications attributed to CDI. Severity was assessed on the basis of 8 severity score indices, using published criteria for severe CDI as the benchmark. The 8 severity score indices studied were Beth Israel, University of Pittsburgh Medical Center version 1, University of Pittsburgh Medical Center version 2, Hines VA, modified University of Illinois, University of Calgary version 1, University of Calgary version 2, and University of Temple.

Of 184 patients with CDI evaluated, 19 had severe cases and 165 had nonsevere cases, as assessed on the basis of the defined severe CDI criteria. Sensitivities of the 8 severity score indices studied ranged from 63.2% to 84.2%, and specificities ranged from 59.4% to 93.9%. The Hines VA index had the highest kappa score (0.69 [95% confidence interval, 0.54-0.83]), followed by the University of Pittsburgh Medical Center version 1 index. Independent risk factors for severe CDI determined by multivariate analysis were abdominal distention (P = .007), fever (temperature, 38.0°C or above; P = .042), white blood cell count of at least 20,000 cells/mm3 (P = .035), and hypoalbuminemia (serum albumin level less than 3 mg/dL; P = .029).

The Hines VA CDI severity score index appeared to display the strongest correlation for predicting more severe forms of CDI.

The objectives of this study were to determine the incidence density and the occurrence of horizontal spread of highly resistant gram-negative rods (HR-GNRs) in Dutch hospitals. The factors that influence these outcome measures were also investigated.

All patients with HR-GNRs, as determined by sample testing, who were hospitalized in 1 of 18 hospitals during a 6-month period (April through October 2007) were included in this study. For all available isolates, the species was identified, susceptibility was determined (including the presence of extended-spectrum β-lactamases [ESBLs]), and molecular typing was performed. On the basis of a combination of species identification, molecular typing, and epidemiological data, the occurrence of nosocomial transmission was determined.

The mean incidence density of patients with HR-GNRs was 55 per 100,000 patient-days (cumulative incidence, 39 per 10,000 patients admitted). A facility being a university hospital was a statistically significant (P = .03) independent determinant of a higher incidence of patients with HR-GNRs. The majority of HR-GNR isolates were ESBL producers. The adjusted transmission index—the ratio between secondary and primary cases—in the participating hospitals ranged from 0.0 to 0.2. The overall adjusted transmission index of HR-GNRs was 0.07. No determinants for a higher transmission index were identified.

The nosocomial transmission rate of HR-GNRs was relatively low in all hospitals where well-established transmission-based precautions were used. The incidence density of patients with HR-GNRs was higher in university hospitals, probably due to the patient population and the complexity of the care provided.

Controversy exists over whether Clostridium difficile infection (CDI) commonly occurs in long-term care facility residents who have not been recently transferred from an acute care hospital.

To assess the incidence and outcome of CDI in a long-term care facility.

Retrospective cohort study in a 262-bed long-term care Veterans Affairs facility in Pittsburgh, Pennsylvania, for the period January 2004 through June 2010. CDI was identified by positive stool C. difficile toxin assay and acute diarrhea. Patients were categorized as hospital-associated CDI (HACDI) or long-term care facility–associated CDI (LACDI) and followed for 6 months.

The annual rate of CDI varied between 0.11 and 0.23 per 1,000 resident-days for HACDI patients and between 0.04 and 0.28 per 1,000 resident-days for LACDI patients. We identified 162 patients, 96 patients (59.3%) with HACDI and 66 patients (40.7%) with LACDI. Median age was 74 and 77 years, respectively, for HACDI and LACDI (P = .055) patients. There were more patients with at least 1 relapse of CDI during 6 months of follow up in LACDI patients (32/66, 48.5%) than in HACDI patients (28/96, 29.2%; P = .009). Logistic regression showed that ages of at least 75 years (odds ratio [OR], 2.33; 95% confidence interval [CI], 1.07–5.07; P = .033), more than 2 transfers to an acute care hospital (OR, 7.88; 95% CI, 1.88–32.95; P = .005), and LACDI (OR, 3.15; 95% CI, 1.41–7.05; P = .005) were associated with relapse of CDI.

Forty percent of CDI cases were acquired within the long-term care facility, indicating a substantial degree of transmission. Optimal strategies to prevent CDI in the long-term care facility are needed.

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 document successful substantial increases in healthcare worker influenza vaccination rates and to identify reasons for success and failure.

(1) Four-year longitudinal characterization of facility vaccination rates, (2) Web-based facility-level questionnaire for influenza coordinators to identify success factors in year 3, and (3) semistructured telephone interviews of influenza coordinators at facilities with substantial increases or declines in year 4.

National single-payer hospital (healthcare) system with 153 hospitals in 5 levels of complexity.

Facility leadership staff.

(1) Vaccination data collected from management sources (doses from pharmacies, denominator data from payrolls); (2) a Web-based survey aligned with a previously administered instrument (Wisconsin Health Department), piloted in-house, modified to reflect national strategies and improvements; and (3) semistructured telephone interviews with influenza coordinators at facilities that improved or worsened by more than 20% between the 2007–2008 and 2008–2009 influenza seasons.

Vaccination acceptance rates improved from 45% of healthcare workers in 2005–2006 to 66.5% in 2008–2009. Facilities with lower complexity had higher vaccination rates. No individual factors were associated with improved performance.

Sustained management attention can lead to improvements in healthcare worker influenza vaccination rates. Wavering of attention, though, may lead to rapid loss of effectiveness. Declination statements in this system did not contribute to vaccine acceptance.

Carbapenem-resistant Enterobacteriaceae (CRE) are rapidly emerging in hospitals in the United States and are posing a significant threat. To better understand the transmission dynamics and the acquisition of resistant strains, a thorough analysis of epidemiologic and molecular characteristics was performed.

CRE isolated at Detroit Medical Center were analyzed from September 2008 to September 2009. blaKPC genes were investigated by polymerase chain reaction (PCR), and repetitive extragenic palindromic PCR (rep-PCR) was used to determine genetic similarity among strains. Epidemiologic and outcomes analyses were performed.

Ninety-two unique patient CRE isolates were recovered. Sixty-eight strains (74%) were Klebsiella pneumoniae, 7 were Klebsiella oxytoca, 15 were Enterobacter species, and 2 were Escherichia coli. Fifteen isolates (16%) were resistant to Colistin, 14 (16%) were resistant to tigecycline, and 2 were resistant to all antimicrobials tested. The mean ± standard deviation age of patients was 63 ± 2 years. Sixty patients (68%) were admitted to the hospital from long-term care facilities. Only 70% of patients received effective antimicrobial therapy when infection was suspected, with a mean time to appropriate therapy of 120 ± 23 hours following sample culturing. The mean length of hospitalization after sample culturing was 18.6 ± 2.5 days. Of 57 inpatients, 18 (32%) died in the hospital. Independent predictors for mortality were intensive care unit stay (odds ratio [OR], 15.8; P = .003) and co-colonization with CRE and either Acinetobacter baumannii or Pseudomonas aeruginosa (OR, 17.2; P = .006). Among K. pneumoniae CRE, rep-PCR revealed 2 genetically related strains that comprised 70% and 20% of isolates, respectively.

In this large U.S. cohort of patients with CRE infection, which reflects the modern continuum of medical care, co-colonization with CRE and A. baumannii or P. aeruginosa was associated with increased mortality. Two predominant clones of K. pneumoniae accounted for the majority of cases of CRE infection.

To investigate the mode of transmission of and assess control measures for an outbreak of carbapenem-resistant (multidrug-resistant) Acinetobacter baumannii infection involving 6 premature infants.

An outbreak investigation based on medical record review was performed for each neonate during the outbreak (from November 2008 through January 2009) in conjunction with an infection control investigation.

A 36-bed, level 3 neonatal intensive care unit in a university-affiliated teaching hospital in Detroit, Michigan.

Specimens were obtained for surveillance cultures from all infants in the unit. In addition, geographic cohorting of affected infants and their nursing staff, contact isolation, re-emphasis of adherence to infection control practices, environmental cleaning, and use of educational modules were implemented to control the outbreak.

Six infants (age, 10-197 days) with multidrug-resistant A. baumannii infection were identified. All 6 infants were premature (gestational age, 23-30 weeks) and had extremely low birth weights (birth weight, 1000 g or less). Conditions included conjunctivitis (2 infants), pneumonia (4 infants), and bacteremia (1 infant). One infant died of causes not attributed to infection with the organism; the remaining 5 infants were discharged home. All surveillance cultures of unaffected infants yielded negative results.

The spread of multidrug-resistant A. baumannii infection was suspected to be due to staff members who spread the pathogen through close contact with infants. Clinical staff recognition of the importance of multidrug-resistant A. baumannii recovery from neonatal intensive care unit patients, geographic cohorting of infected patients, enhanced infection control practices, and staff education resulted in control of the spread of the organism.

Cephalosporins are recommended for antibiotic prophylaxis to prevent cardiothoracic surgical site infections (SSIs) except in patients with β-lactam allergy or in settings with a “high” prevalence of methicillin-resistant Staphylococcus aureus (MRSA) among S. aureus isolates (hereafter, “MRSA prevalence”); however, “high” remains undefined. We sought to identify the MRSA prevalence at which glycopeptide prophylaxis would minimize SSIs relative to β-lactam prophylaxis.

We developed a decision analysis model to estimate SSI likelihood when either glycopeptides or β-lactams were used for prophylaxis in cardiothoracic surgery. Event probabilities were derived from a systematic literature review. A similar cost-minimization model was also developed.

At 0% MRSA prevalence, SSI probability was 3.64% with glycopeptide prophylaxis and 3.49% with β-lactam prophylaxis. At MRSA prevalences of 10%, 20%, 30%, or 40%, SSI probabilities with glycopeptide prophylaxis did not change, but they were 3.98%, 4.48%, 4.97%, and 5.47% with β-lactam prophylaxis. The threshold of MRSA prevalence at which glycopeptide prophylaxis minimized SSI probability and cost was 3%. In sensitivity analyses, variations in most model estimates only modestly affected the threshold.

Glycopeptide prophylaxis minimizes the risk of SSIs and cost when MRSA prevalence exceeds 3%. At very low MRSA prevalence (between 3% and 10%), the SSI minimization provided by glycopeptide prophylaxis is small and may be within the error of the model. Given the current MRSA prevalence in most community and healthcare settings, clinicians should consider routine prophylaxis with vancomycin. Our findings may have important policy implications, as benefits in cardiothoracic surgery antibiotic prophylaxis must be weighed against the limitations of increased glycopeptide use.

Nosocomial outbreaks of norovirus infection pose a great challenge to the infection control team.

Between November 1, 2009, and February 28, 2010, strategic infection control measures were implemented in a hospital network. In addition to timely staff education and promotion of directly observed hand hygiene, reverse-transcription polymerase chain reaction for norovirus was performed as an added test by the microbiology laboratory for all fecal specimens irrespective of the request for testing. Laboratory-confirmed cases were followed up by the infection control team for timely intervention. The incidence of hospital-acquired norovirus infection per 1,000 potentially infectious patient-days was compared with the corresponding period in the preceding 12 months, and the incidence in the other 6 hospital networks in Hong Kong was chosen as the concurrent control. Phylogenetic analysis of norovirus isolates was performed.

Of the 988 patients who were tested, 242 (25%) were positive for norovirus; 114 (47%) of those 242 patients had norovirus detected by our added test. Compared with the corresponding period in the preceding 12 months, the incidence of hospital-acquired norovirus infection decreased from 131 to 16 cases per 1,000 potentially infectious patient-days (P < .001 ), although the number of hospital-acquired infections was low in both the study period (n = 8) and the historical control periods (n = 11). The incidence of hospital-acquired norovirus infection in our hospital network (0.03 cases per 1,000 patient-days) was significantly lower than that of the concurrent control (0.06 cases per 1,000 patient-days) (P = .015). Forty-three (93%) of 46 norovirus isolates sequenced belonged to the genogroup II.4 variant.

Strategic infection control measures with an added test maybe useful in controlling nosocomial transmission of norovirus.

To establish whether continuous subglottic suctioning (CSS) could be cost-effective.

Cost-benefit analysis, based on a hypothetical replacement of conventional ventilation (CV) with CSS.

A surgical intensive care unit (SICU) of a tertiary care university hospital in France.

All consecutive patients receiving ventilation in the SICU in 2006.

Efficacy data for CSS were obtained from the literature and applied to the SICU of our hospital. Costs for CV and CSS were provided by the hospital pharmacy; costs for ventilator-associated pneumonia (VAP) were obtained from the literature. The cost per averted VAP episode was calculated, and a sensitivity analysis was performed on VAP incidence and on the number of tubes required for each patient.

At our SICU in 2006, 416 patients received mechanical ventilation for 3,487 ventilation-days, and 32 VAP episodes were observed (7.9 episodes per 100 ventilated patients; incidence density, 9.2 episodes per 10,000 ventilation-days). Based on the hypothesis of a 29% reduction in the risk of VAP with CSS than CV, 9 VAP episodes could have been averted. The additional cost of CSS for 2006 was estimated to be €10,585.34. The cost per averted VAP episode was €1,176.15. Assuming a VAP cost of €4,387, a total of 3 averted VAP episodes would neutralize the additional cost. For a low VAP incidence of 6.6%, the cost per averted VAP would be €1,323. If each patient required 2 tubes during ventilation, the cost would be €1,383.69 per averted VAP episode.

Replacement of CV with CSS was cost-effective even when assuming the most pessimistic scenario of VAP incidence and costs.

Manual surveillance for central line-associated bloodstream infections (CLABSIs) by infection prevention practitioners is time-consuming and often limited to intensive care units (ICUs). An automated surveillance system using existing databases with patient-level variables and microbiology data was investigated.

Patients with a positive blood culture in 4 non-ICU wards at Barnes-Jewish Hospital between July 1, 2005, and December 31, 2006, were evaluated. CLABSI determination for these patients was made via 2 sources; a manual chart review and an automated review from electronically available data. Agreement between these 2 sources was used to develop the best-fit electronic algorithm that used a set of rules to identify a CLABSI. Sensitivity, specificity, predictive values, and Pearson's correlation were calculated for the various rule sets, using manual chart review as the reference standard.

During the study period, 391 positive blood cultures from 331 patients were evaluated. Eighty-five (22%) of these were confirmed to be CLABSI by manual chart review. The best-fit model included presence of a catheter, blood culture positive for known pathogen or blood culture with a common skin contaminant confirmed by a second positive culture and the presence of fever, and no positive cultures with the same organism from another sterile site. The best-performing rule set had an overall sensitivity of 95.2%, specificity of 97.5%, positive predictive value of 90%, and negative predictive value of 99.2% compared with intensive manual surveillance.

Although CLABSIs were slightly overpredicted by electronic surveillance compared with manual chart review, the method offers the possibility of performing acceptably good surveillance in areas where resources do not allow for traditional manual surveillance.

To determine the prevalence of health care-associated infection (HAI) in older people in acute care hospitals, detailing the specific types of HAI and specialties in which these are most prevalent.

Secondary analysis of the Scottish National Healthcare Associated Infection Prevalence Survey data set.

All inpatients in acute care (n = 11,090) in all acute care hospitals in Scotland (n = 45).

The study found a linear relationship between prevalence of HAI and increasing age (P<.0001) in hospital inpatients in Scotland. Urinary tract infections and gastrointestinal infections represented the largest burden of HAI in the 75–84- and over-85-year age groups, and surgical-site infections represented the largest burden in inpatients under 75 years of age. The prevalence of urinary catheterization was higher in each of the over-65 age groups (P<.0001). Importantly, this study reveals that a high prevalence of HAI in inpatients over the age of 65 years is found across a range of specialties within acute hospital care. An increased prevalence of HAI was observed in medical, orthopedic, and surgical specialties.

HAI is an important outcome indicator of acute inpatient hospital care, and our analysis demonstrates that HAI prevalence increases linearly with increasing age (P<.0001). Focusing interventions on preventing urinary tract infection and gastrointestinal infections would have the biggest public health benefit. To ensure patient safety, the importance of age as a risk factor for HAI cannot be overemphasized to those working in all areas of acute care.

Since hospitals in a region often share patients, an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) infection in one hospital could affect other hospitals.

Using extensive data collected from Orange County (OC), California, we developed a detailed agent-based model to represent patient movement among all OC hospitals. Experiments simulated MRSA outbreaks in various wards, institutions, and regions. Sensitivity analysis varied lengths of stay, intraward transmission coefficients (β), MRSA loss rate, probability of patient transfer or readmission, and time to readmission.

Each simulated outbreak eventually affected all of the hospitals in the network, with effects depending on the outbreak size and location. Increasing MRSA prevalence at a single hospital (from 5% to 15%) resulted in a 2.9% average increase in relative prevalence at all other hospitals (ranging from no effect to 46.4%). Single-hospital intensive care unit outbreaks (modeled increase from 5% to 15%) caused a 1.4% average relative increase in all other OC hospitals (ranging from no effect to 12.7%).

MRSA outbreaks may rarely be confined to a single hospital but instead may affect all of the hospitals in a region. This suggests that prevention and control strategies and policies should account for the interconnectedness of health care facilities.

To describe the identification, management, and clinical characteristics of hospitalized patients with influenza-like illness (ILI) during the peak period of activity of the 2009 pandemic strain of influenza A virus subtype H1N1 (2009 H1N1).

Retrospective review of electronic medical records.

Hospitalized patients who presented to the emergency department during the period October 18 through November 14, 2009, at 4 hospitals in Cook County, Illinois, with the capacity to perform real-time reverse-transcriptase polymerase chain reaction testing for influenza.

Vital signs and notes recorded within 1 calendar day after emergency department arrival were reviewed for signs and symptoms consistent with ILI. Cases of ILI were classified as recognized by healthcare providers if an influenza test was performed or if influenza was mentioned as a possible diagnosis in the physician notes. Logistic regression was used to determine the patient attributes and symptoms that were associated with ILI recognition and with influenza infection.

We identified 460 ILI case patients, of whom 412 (90%) had ILI recognized by healthcare providers, 389 (85%) were placed under airborne or droplet isolation precautions, and 243 (53%) were treated with antiviral medication. Of 401 ILI case patients tested for influenza, 91 (23%) had a positive result. Fourteen (3%) ILI case patients and none of the case patients who tested positive for influenza had sore throat in the absence of cough.

Healthcare providers identified a high proportion of hospitalized ILI case patients. Further improvements in disease detection can be made through the use of advanced electronic health records and efficient diagnostic tests. Future studies should evaluate the inclusion of sore throat in the ILI case definition.