To compare and contrast the epidemiology of polymicrobial and monomicrobial bloodstream infections (BSIs) in newborn intensive care unit (NICU) patients.

Retrospective, matched case-control study.

The Yale-New Haven Hospital NICU from 1989 through 2006.

NICU patients with BSIs.

Each neonate with polymicrobial BSI (case patient) was matched to one neonate with monomicrobial BSI (control patient), by birth date, weight, and sex; and univariate and multivariate analyses were performed.

One hundred five cases of polymicrobial BSI were identified in 102 infants, representing 10% of all neonatal BSIs in our institution. Coagulase-negative staphylococci were the most common organisms recovered from culture. Infants with polymicrobial BSI had later onset of infection than infants with monomicrobial BSI (mean day of life, 37.5 vs 24.0; P< .001). Polymicrobial BSI occurred more frequently among infants with a severe underlying condition than in those without such a condition (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.1-3.2) and among infants requiring an indwelling central venous catheter for a prolonged duration (mean, 16.9 days, compared with 9.8 days for infants with monomicrobial BSI; P = .001). Multivariate analysis revealed that later onset of infection (adjusted OR [aOR], 1.02; 95% CI, 1.00-1.04) and presence of a severe underlying condition (aOR, 1.91; 95% CI, 1.12-3.38) were independent risk factors for polymicrobial BSI. No differences in outcome or mortality were observed.

Changes in the microbiology and epidemiology of NICU-related polymicrobial BSI have occurred since the last North American review. In the present study, although differences were observed, most risk factors and outcomes were similar between monomicrobial BSI and polymicrobial BSI. Epidemiologic surveillance is critical to identify trends associated with neonatal polymicrobial BSI, particularly those that may impact preventative strategies, diagnostic measures, and therapeutic interventions.

The symptoms of influenza infection in outpatients are well described. The Centers for Disease Control and Prevention (CDC) definition of an influenza-like illness (ILI) includes fever and cough or sore throat. Few data exist on the clinical presentation of influenza in hospitalized patients, which may be distinct from the clinical presentation of influenza in ambulatory patients because of underlying medical conditions and medications.

Retrospective case-control study.

A 1,250-bed urban teaching hospital.

A total of 369 patients were admitted to the general medicine wards during 3 consecutive influenza seasons (2001-2004): 123 case patients with laboratory-confirmed influenza that was diagnosed during routine medical care and 246 control patients with active surveillance culture results negative for influenza.

Data on demographic characteristics, comorbidities, and signs and symptoms were obtained from a review of the medical records of the case and control patients. Analysis included stratified analysis and logistic regression.

Cough, coryza, sore throat, and fever were more common in patients with influenza infection. The CDC's definition of an ILI had a sensitivity of 43% and specificity of 86% in the study population, with a crude odds ratio (OR) of 4.7 (95% confidence interval [CI], 2.8-7.8). The sensitivity of the CDC's definition of an ILI decreased to 21% among asthmatic patients, who had similar rates of fever and/or ILI with or without influenza. By logistic regression, ILI was strongly associated with influenza infection in patients without asthma (adjusted OR, 7.5 [95% CI, 4.1-13.7]) but not in patients with asthma (adjusted OR, 1.1 [95% CI, 0.13-10]). The positive predictive value of an ILI in asthmatic patients was 50%.

The CDC's definition of an ILI lacks sensitivity among hospitalized patients, and the presence of an ILI is not associated with influenza infection in asthmatic patients.

The use of a clinical prediction score to improve the practice of instituting airborne-transmission precautions in patients with suspected tuberculosis holds promise for increasing appropriate isolation and decreasing unnecessary isolation. The objective of this study was to derive and validate a clinical prediction score for patients with suspected tuberculosis.

We used a case—control study design to evaluate differences between patients with a diagnosis of tuberculosis and those placed under airborne precautions who had negative culture results. We developed risk scores based on a multivariable analysis of independently significant factors associated with tuberculosis. Subsequently, we evaluated the sensitivity and specificity of the score in a separate (validation) cohort of patients.

Within our population, we found 4 clinical factors associated with tuberculosis: chronic symptoms (odds ratio [OR], 10.2 [95% confidence interval {CI}, 2.95-35.4]), upper lobe disease on chest radiograph (OR, 5.27 [95% CI, 1.6-17.23]), foreign-born status (OR, 7.01 [95% CI, 2.1-23.8]), and immunocompromised state other than human immunodeficiency virus infection (OR, 8.14 [95% CI, 2.08-31.8]). Shortness of breath (OR, 0.13 [95% CI, 0.04-0.45]) was found to be associated with non-tuberculosis diagnoses and considered a negative predictor in the model. Using a cut-off point to maximize sensitivity, we applied the prediction rule to the validation cohort, resulting in a sensitivity of 97% and a specificity of 42%.

The tuberculosis prediction rule derived from our patient population could improve utilization of airborne precautions. Clinical prediction rules continue to show their utility for improvement in isolation practices in different demographic areas.

To determine what practices are used by hospitals to prevent ventilator-associated pneumonia (VAP) and, through qualitative methods, to understand more fully why hospitals use certain practices and not others.

Mixed-methods, sequential explanatory study.

We mailed a survey to the lead infection control professionals at 719 US hospitals (119 Department of Veterans Affairs [VA] hospitals and 600 non-VA hospitals), to determine what practices are used to prevent VAP. We then selected 14 hospitals for an in-depth qualitative investigation, to ascertain why certain infection control practices are used and others not, interviewing 86 staff members and visiting 6 hospitals.

The survey response rate was 72%; 83% of hospitals reported using semirecumbent positioning, and only 21% reported using subglottic secretion drainage. Multivariable analyses indicated collaborative initiatives were associated with the use of semirecumbent positioning but provided little guidance regarding the use of subglottic secretion drainage. Qualitative analysis, however, revealed 3 themes: (1) collaboratives strongly influence the use of semirecumbent positioning but have little effect on the use of subglottic secretion drainage; (2) nurses play a major role in the use of semirecumbent positioning, but they are only minimally involved with the use of subglottic secretion drainage; and (3) there is considerable debate about the evidence supporting subglottic secretion drainage, despite a meta-analysis of 5 randomized trials of subglottic secretion drainage that generally supported this preventive practice, compared with only 2 published randomized trials of semirecumbent positioning, one of which concluded that it was ineffective at preventing the development of VAP.

Semirecumbent positioning is commonly used to prevent VAP, whereas subglottic secretion drainage is used far less often. We need to understand better how evidence related to prevention practices is identified, interpreted, and used to ensure that research findings are reliably translated into clinical practice.

To validate the National Nosocomial Infection Surveillance (NNIS) risk index as a tool to account for differences in case mix when reporting rates of complex surgical site infection (SSI).

Prospective cohort study.

Twenty-four community hospitals in the southeastern United States.

We identified surgical procedures performed between January 1, 2005, and June 30, 2007. The Goodman-Kruskal gamma or G statistic was used to determine the correlation between the NNIS risk index score and the rates of complex SSI (not including superficial incisional SSI). Procedure-specific analyses were performed for SSI after abdominal hysterectomy, cardiothoracic procedures, colon procedures, insertion of a hip prosthesis, insertion of a knee prosthesis, and vascular procedures.

A total of 2,257 SSIs were identified during the study period (overall rate, 1.19 SSIs per 100 procedures), of which 1,093 (48.4%) were complex (0.58 complex SSIs per 100 procedures). There were 45 complex SSIs identified following 7,032 abdominal hysterectomies (rate, 0.64 SSIs per 100 procedures); 63 following 5,318 cardiothoracic procedures (1.18 SSIs per 100 procedures); 139 following 5,144 colon procedures (2.70 SSIs per 100 procedures); 63 following 6,639 hip prosthesis insertions (0.94 SSIs per 100 procedures); 73 following 9,658 knee prosthesis insertions (0.76 SSIs per 100 procedures); and 55 following 6,575 vascular procedures (0.84 SSIs per 100 procedures). All 6 procedure-specific rates of complex SSI were significantly correlated with increasing NNIS risk index score (P< .05).

Some experts recommend reporting rates of complex SSI to overcome the widely acknowledged detection bias associated with superficial incisional infection. Furthermore, it is necessary to compensate for case-mix differences in patient populations, to ensure that intrahospital comparisons are meaningful. Our results indicate that the NNIS risk index is a reasonable method for the risk stratification of complex SSIs for several commonly performed procedures.