Surgical-site infections, the third most common class of nosocomial infections, cause substantial morbidity and mortality and increase hospital costs. Surveillance programs can lead to reductions in surgical-site infection rates of 35% to 50%. Herein, we will discuss the practical aspects of implementing a hospital-based surveillance program for surgical-site infections. We will review surveillance methods, patient populations that should be screened, and interventions that could reduce infection rates.

Healthcare professionals often are presented with data that appear to indicate an upward or downward trend over time. For example, admissions of acquired immunodeficiency syndrome (AIDS) patients appear to be increasing, cesarean section rates appear to be decreasing, or nosocomial pneumonia rates appear to be increasing. Critical decisions sometimes are based on such trends, which often are presented without a statistical analysis. Those responsible for decision making may be left wondering whether these apparent trends represent only chance variation. Graphs showing trends over time generally present one of three kinds of outcome data: counts (eg, three AIDS admissions), proportions (eg, 10 cesarean sections per 100 total deliveries), or person-time data (eg, 13 cases of nosocomial pneumonia per 10,000 patient days). Using familiar examples and a minimum of technical language, we illustrate the analysis of time trends.

Nosocomial pneumonia is defined as an infection of lung parenchyma that was neither present nor incubating at the time of the patient's admission to the hospital. In the United States, hospital-acquired pneumonia is the second most common nosocomial infection and accounts for the most deaths from nosocomial infection. We describe how infection control personnel can use targeted surveillance to identify clusters of cases and to prevent pneumonia. We also discuss common pathogens that cause nosocomial pneumonia; ventilator-associated pneumonia; and strategies for prevention of hospital-acquired pneumonia.

Awareness is growing of the role of pertussis infection among adolescents and adults, and of the possibility of nosocomial transmission. However, pertussis remains difficult to diagnose. We report a case of nosocomially acquired pertussis in a healthcare worker, diagnosed by polymerase chain reaction. The high sensitivity and rapid turnaround time for this test is useful to confirm the diagnosis when advising a healthcare worker to refrain from working.

Vancomycin-resistant enterococci (VRE) often contaminate the hospital environment. We examined the activity of commonly used disinfectants against eight strains of VRE, using a quantitative suspension test method. Isopropyl alcohol and sodium hypochlorite were highly effective. Hydrogen peroxide was ineffective for all strains. After 10 minutes of incubation (the manufacturers' recommended time of exposure), three phenolic and three quaternary ammonium compounds also were highly effective. After 3 minutes of exposure, however, occasional failures did occur. With the exception of 3% hydrogen peroxide, most disinfectants appear to be active against VRE.

Decision analysis offers powerful techniques to understand and evaluate uncertain clinical situations better. Decision analytic models are appearing with increasing frequency in health policy planning, clinical information and decision-support computer systems, evaluations of clinical pathways, development of clinical practice or utilization review guidelines, and epidemiologic research. This article describes the structure, application, and limitations of the more popular decision analytic methods, including decision trees, Markov models, Monte Carlo simulation, survival and hazard functions, fuzzy logic, and sensitivity analysis. Understanding the nature of these methods will help readers to assess better the appropriateness of their use in published reports.

The rate of purified protein derivative (PPD) conversion in workers at our hospital increased to 1.7% in 1991. After implementation of mandatory respiratory isolation of patients with community-acquired pneumonia, the rate dropped to 0.6%. This policy may protect workers in institutions where the majority of patients with pneumonia have risk factors for tuberculosis.

Over a 1-week period, Neisseria meningitidis serogroup B was recovered from two patients in the intensive-care unit (ICU). A cross-infection was presumed when one patient developed invasive meningococcal disease and another patient was found to be colonized. Investigation by molecular typing showed that these cases were not related, demonstrating the value of molecular typing when investigating potential cross-infections in a closed environment such as the ICU.

An outbreak of gastroenteritis caused by Norwalk-like virus occurred in two areas of the hospital: area 1, consisting of three adjacent and interconnected wards, with mostly elderly patients; and area 2, an acute ward in a separate building with elderly patients. In area 1, 40 patients and 20 staff were affected; in area 2, 18 patients and 14 staff were affected. Infection control measures were instituted in consultation with the government health authority. These measures did not appear to affect the course of the outbreak, but may have prevented spread to other wards.

In a prospective study, cultures were obtained of all intravascular catheters removed from children in an intensivecare unit. Of 366 catheters removed from 217 children, 110 (30%) were found to be colonized, most commonly with coagulase-negative staphylococci. Despite the high rate of colonization, there were only nine instances (2%) of catheter-related bacteremia.