We evaluated 4 important outcomes associated with postoperative nosocomial infection: costs, mortality, excess length of stay, and utilization of healthcare resources.

The outcomes for patients who underwent general, cardiothoracic, and neurosurgical operations were recorded during a previous clinical trial. Multivariable analyses including significant covariates were conducted to determine whether nosocomial infection significantly affected the outcomes.

A large tertiary care medical center and an affiliated Veterans Affairs Medical Center.

A total of 3,864 surgical patients.

The overall nosocomial infection rate was 11.3%. Important covariates included age, Karnofsky score, McCabe and Jackson classification of the severity of underlying disease, National Nosocomial Infection Surveillance system risk index, and number of comorbidities. After accounting for covariates, nosocomial infection was associated with increased postoperative length of stay, increased costs, increased hospital readmission rate, and increased use of antimicrobial agents in the outpatient setting. Nosocomial infection was not associated independently with a significantly increased risk of death in this surgical population.

Postoperative nosocomial infection was associated with increased costs of care and with increased utilization of medical resources. To accurately assess the effects of nosocomial infections, one must take into account important covariates. Surgeons seeking to decrease the cost of care and resource utilization must identify ways to decrease the rate of postoperative nosocomial infection.

To evaluate the influence of performance of active surveillance cultures for methicillin-resistant Staphylococcus aureus (MRSA) on the incidence of nosocomial MRSA bacteremia in an endemic hospital.

Before-after trial.

A 700-bed hospital.

All patients admitted to the hospital who were at high risk for MRSA bacteremia.

Performance of surveillance cultures for detection of MRSA were recommended for all patients at high risk, and contact isolation was implemented for patients with positive results of culture. Each MRSA-positive patient received one course of eradication treatment. We compared the total number of surveillance cultures, the percentage of surveillance cultures with positive results, and the number of MRSA bacteremia cases before the intervention (from January 2002 through February 2003) after the start of the intervention (from July 2003 through October 2004).

The number of surveillance cultures performed increased from a mean of 272.57 cultures/month before the intervention to 865.83 cultures/month after the intervention. The percentage of surveillance cultures with positive results increased from 3.13% before to 5.22% after the intervention (P<.001). The mean number of MRSA bacteremia cases per month decreased from 3.6 cases before the intervention to 1.8 cases after the intervention (P< 0.001).

Active surveillance culture is important for identifying hidden reservoirs of MRSA. Contact isolation can prevent new colonization and infection and lead to a significant reduction of morbidity and healthcare costs.

To describe an infection control network (the Duke Infection Control Outreach Network [DICON]) and its impact on nosocomial infection rates in community hospitals.

Prospective cohort study of rates of nosocomial infections and exposures of employees to bloodborne pathogens in hospitals during the first 3 years of their affiliation with DICON. Attributable cost and mortality estimates were obtained from published studies.

Twelve community hospitals in North Carolina and Virginia.

During the first 3 years of hospital affiliation with DICON, annual rates of nosocomial bloodstream infections at study hospitals decreased by 23% (P = .009). Annual rates of nosocomial infection and colonization due to methicillin-resistant Staphylococcus aureus decreased by 22% (P = .002), and rates of ventilator-associated pneumonia decreased by 40% (P = .001). Rates of exposure of employees to bloodborne pathogens decreased by 18% (P = .003).

The establishment of an infection control network within a group of community hospitals was associated with substantial decreases in nosocomial infection rates. Standard surveillance methods, frequent data analysis and feedback, and interventions based on guidelines and protocols from the Centers for Disease Control and Prevention were the principal strategies used to achieve these reductions. In addition to lessening the adverse clinical outcomes due to nosocomial infections, these reductions substantially decreased the economic burden of infection: the decline in nosocomial bloodstream infections and ventilator-associated pneumonia alone yielded potential savings of $578,307 to $2,195,954 per year at the study hospitals.

Hospitalized premature infants are particularly vulnerable to morbidity and mortality from pertussis. Effective prevention and investigative and control measures are not well described.

To identify the source of nosocomial pertussis in a 2-month-old premature infant in a neonatal intermediate care nursery (ICN) and to critically review the investigation and outbreak control measures.

An ICN and a neonatal intensive care unit.

We queried healthcare workers (HCWs) and family members about cough illness and contacted potentially exposed patients to determine whether they had symptoms of pertussis. Culture and polymerase chain reaction (PCR) testing for Bordetella pertussis were performed by the hospital laboratory with specimens collected from symptomatic patients and HCWs. Levels of pertussis toxin immunoglobulin G antibodies were measured in HCWs with cough of at least 14 days' duration at a public health laboratory. Extensive control measures were instituted.

Four ICN HCWs met the clinical case definition for presence of pertussis. Serologic test results were positive for 3 of the HCWs. The primary case patient was a 36-year-old HCW with a cough illness of 3-weeks' duration that was accompanied by paroxysms, whoop, posttussive emesis, and pneumothorax. Among the 4 affected HCWs, the duration of cough illness prior to identification of the infant index patient ranged from 11 to 25 days. Outbreak control measures included isolation of the infant case patient, furlough and treatment of symptomatic HCWs, administration of chemoprophylaxis to contacts, and surveillance for additional cases. Seventy-two infant patients and 72 HCWs were exposed and were given antibiotic prophylaxis. One additional case of pertussis, confirmed by PCR and culture, occurred in a resident physician who declined prophylaxis; she had cared for the index patient but had no contact with symptomatic HCWs.

HCWs or patients may serve as the source of pertussis in nosocomial outbreaks, which can result in substantial morbidity and outlay of resources for control measures. Our review suggested that a diagnosis of pertussis should be an early consideration for HCWs with cough illness. Targeted pertussis immunization of HCWs, employee health policies that provide for testing and furlough of HCWs with prolonged cough, and monitoring of HCWs for compliance with infection control measures could reduce the morbidity and costs associated with pertussis outbreaks. These measures will require evaluation of their effectiveness.

To evaluate individuals at high risk for tuberculosis exposure who had a history of a positive tuberculin skin test (TST) result in order to determine the prevalence of unsuspected negative TST results. To confirm these findings with the QuantiFERON-TB test (QFT), an in vitro whole-blood assay that measures tuberculin-induced secretion of interferon-γ.

This survey was conducted from November 2001 through December 2003 at 3 sites where TST screening is regularly done. Detailed histories and reviews of medical records were performed. TSTs were placed and read by 2 experienced healthcare workers, and blood was drawn for QFT. Any subject with a negative result of an initial TST during the study (induration diameter, <10 mm) underwent a second TST and a second QFT. The TST-negative group comprised individuals for whom both TSTs had an induration diameter of <10 mm. The confirmed-negative group comprised individuals for whom both TSTs yielded no detectable induration and results of both QFTs were negative.

A total of 67 immunocompetent subjects with positive results of a previous TST were enrolled in the study. Of 56 subjects who completed the TST protocol, 25 (44.6%; 95% confidence interval [CI], 31.6%-57.6%) were TST negative (P<.001). Of 31 subjects who completed the TST protocol and the QFT protocol, 8 (25.8%; 95% CI, 10.4%-41.2%) were confirmed negative (P<.005).

A significant proportion of subjects with positive results of a previous TST were TST negative in this study, and a subset of these were confirmed negative. These individuals' TST status may have reverted or may never have been positive. It will be important in future studies to determine whether such individuals lack immunity to tuberculosis and whether they should be considered for reentry into tuberculosis screening programs.

Surveillance of surgical site infections (SSIs) is effective in reducing the rates of these complications, but it is extremely time-consuming and, consequently, underused. We determined the sensitivity and specificity of a computer-assisted surveillance system, compared with a conventional method involving review of medical records, and the time saved with the computer-assisted system.

A prospective study was conducted from January 1 to December 31, 2001. With the computer-assisted method, screening for SSIs relied on identification in the laboratory database of positive results of microbiological tests of surgical-site specimens; confirmation was obtained via computer-generated questionnaires completed by the surgeon in charge of the patient. In the conventional method, SSIs were identified by exhaustive chart review. The time spent on surveillance was recorded for both methods.

A 25-bed gastrointestinal surgery unit in a tertiary care hospital.

A total of 766 consecutive patients who underwent gastrointestinal surgery.

The sensitivity of the computer-assisted method was 84.3% (95% confidence interval, 0.66-0.94); the specificity was 99.9%. For the 807 surgical procedures in the study, 197 had an SSI identified by culture of a surgical-site specimen. After elimination of 63 duplicate cultures with positive results, 134 questionnaires were sent to the surgeons, who confirmed 27 SSIs. The conventional method identified 32 SSIs. The computer-assisted method required 60% less time than the conventional method (90 hours vs 223 hours).

Surveillance for SSIs using computer-assisted, laboratory-based screening and case confirmation by surgeons is as efficient as and far less time-consuming than the conventional method of chart review. This method permits routine surveillance for SSIs with reliable accuracy.

Some policy makers have embraced public reporting of healthcare-associated infections (HAIs) as a strategy for improving patient safety and reducing healthcare costs. We compared the accuracy of 2 methods of identifying cases of HAI: review of administrative data and targeted active surveillance.

A cross-sectional prospective study was performed during a 9-month period in 2004 at the Children's Hospital of Philadelphia, a 418-bed academic pediatric hospital. “True HAI” cases were defined as those that met the definitions of the National Nosocomial Infections Surveillance System and that were detected by a trained infection control professional on review of the medical record. We examined the sensitivity and the positive and negative predictive values of identifying HAI cases by review of administrative data and by targeted active surveillance.

We found similar sensitivities for identification of HAI cases by review of administrative data (61%) and by targeted active surveillance (76%). However, the positive predictive value of identifying HAI cases by review of administrative data was poor (20%), whereas that of targeted active surveillance was 100%.

The positive predictive value of identifying HAI cases by targeted active surveillance is very high. Additional investigation is needed to define the optimal detection method for institutions that provide HAI data for comparative analysis.

To identify risk factors for infection with imipenem-resistant Pseudomonas aeruginosa and determine the impact of imipenem resistance on clinical and economic outcomes among patients infected with P. aeruginosa.

An ecologic study, a case-control study, and a retrospective cohort study.

A 625-bed tertiary care medical center.

All patients who had an inpatient clinical culture positive for P. aeruginosa between January 1, 1999, and December 31, 2000.

From 1991 through 2000, the annual prevalence of imipenem resistance among P. aeruginosa isolates increased significantly (P<.001 by the χ2 test for trend). Among 879 patients infected with P. aeruginosa during 1999-2000, a total of 142 had imipenem-resistant P. aeruginosa infection (the case group), whereas 737 had imipenem-susceptible P. aeruginosa infection (the control group). The only independent risk factor for imipenem-resistant P. aeruginosa infection was prior fluoroquinolone use (adjusted odds ratio, 2.52 [95% confidence interval {CI}, 1.61-3.92]; P<.001). Compared with patients infected with imipenem-susceptible P. aeruginosa, patients infected with imipenem-resistant P. aeruginosa had longer subsequent hospitalization durations (15.5 days vs 9 days; P = .02) and greater hospital costs ($81,330 vs $48,381; P<.001). The mortality rate among patients infected with imipenem-resistant P. aeruginosa was 31.1%, compared with 16.7% for patients infected with imipenem-susceptible P. aeruginosa (relative risk, 1.86 [95% CI, 1.38-2.51]; P<.001). In multivariable analyses, there remained an independent association between infection with imipenem-resistant P. aeruginosa and mortality.

The prevalence of imipenem resistance among P. aeruginosa strains has increased markedly in recent years and has had a significant impact on both clinical and economic outcomes. Our results suggest that curtailing use of other antibiotics (particularly fluoroquinolones) may be important in attempts to curb further emergence of imipenem resistance.