Objective: To evaluate the potential contribution of “extrinsic” contamination of intravenous fluids in hospital bacteremia and infection.

Design: Prospective cross-sectional survey of infusate contamination, December 1992 to December 1993.

Setting: A pediatric department (1,500 admissions per year) in a general, urban teaching hospital, serving low-income patients.

Samples and Patients: Infusate samples (0.5 to 1.0 mL) from the injection port used by the staff were taken for cultures from all febrile or septic patients in hospital wards. At least four samples were taken each day; if no febrile or septic patients were available, other patients were sampled at convenience.

Results: A 6.8% positive culture rate (87 contaminates in 1,277 infusates) was obtained, without significant differences among the wards. Gram-negative organisms were recovered from 56 samples (62.9%), mainly of the tribe Klebsielleae (56.1%). Coagulase-negative staphylococci were isolated in 30 samples (33.7%). There was no significant difference between the febrile-septic group and the asymptomatic group in the rate of infusate contamination (P=.59). In eight patients, the same organisms were recovered from infusate and blood culture. The overall bacteremia rate was 2.5 per 100 discharges.

Conclusions: Compared to previous reports, higher infusate contamination rates and different organisms (mainly gram-negative) were observed. In hospitals of underdeveloped countries, nosocomial infection control frequently is disregarded. Infusate contamination may be common and could lead to gram-negative bacteremia. In such settings, it seems advisable to perform surveillance studies to identify infusate contamination, because a single infusate contamination could be a signal for an epidemic.

Objective: To determine the cause(s) of an outbreak of gram-negative bacteremia (GNB) in open-heart–surgery (OHS) patients at hospital A.

Design: Case-control and cohort studies and an environmental survey.

Results: Nine patients developed GNB with Enterobacter cloacae (6), Pseudomonas aeruginosa (5), Klebsiella pneumoniae (3), Serratia marcescens (2), or Klebsiella oxytoca (1) following OHS; five of nine patients had polymicrobial bacteremia. When the GNB patients were compared with randomly selected OHS patients, having had the first procedure of the day (8 of 9 versus 12 of 27, P=.02), longer cardiopulmonary bypass (median, 122 versus 83 minutes, P=.01) or cross-clamp times (median, 75 versus 42 minutes, P=.008), intraoperative dopamine infusion (9 of 9 versus 15 of 27, P=.01), or exposure to scrub nurse 6 (6 of 9 versus 4 of 27, P=.001) were identified as risk factors. When stratified by length of the procedure, only being the first procedure of the day and exposure to scrub nurse 6 remained significant. First procedures used pressure-monitoring equipment that was assembled before surgery and left open and uncovered overnight in the operating room, whereas other procedures used pressure-monitoring equipment assembled immediately before the procedure. At night, operating rooms were cleaned by maintenance personnel who used a disinfectant-water solution sprayed through a hose connected to an automatic diluting system. Observation of the use of this hose documented that this solution could have contacted and entered uncovered pressure-monitoring equipment left in the operating room. Water samples from the hose revealed no disinfectant, but grew P aeruginosa. The outbreak was terminated by setting up pressure-monitoring equipment immediately before the procedure and discontinuing use of the hose-disinfectant system.

Conclusions: This outbreak most likely resulted from contamination of uncovered preassembled pressure-monitoring equipment by water from a malfunctioning spray disinfectant device. Pressure-monitoring equipment should be assembled immediately before use and protected from possible environmental contamination.

Objective: To evaluate the epidemiology of, and control measures for, vancomycin-resistant Enterococcus (VRE) in a renal unit.

Design: A 3-month, prospective, prevalence culture survey of patients on a 24-bed renal unit.

Setting: A 975-bed community teaching hospital.

Patients: Patients admitted to the renal unit over a 3-month period. Patients identified with VRE were each matched with four patients without VRE isolated over the study period.

Interventions/Control Measures: Resistant-organism barrier precautions. To eradicate carriage of VRE, two patients with VRE stool colonization were treated with 5 days of oral doxycycline (100 mg twice per day) and rifampin (300 mg/day).

Results: Seven patients with VRE (8 isolates) were identified. Five isolates were Enterococcus faecium (vancomycin MIC=16 to 256 μg/mL), two were Enterococcus faecalis (MICs=16 and 124 μg/mL), and one was Enterococcus gallinarum (MIC=8.0 μg/mL). Eradication of carriage with VRE was accomplished in two patients treated with doxycycline and rifampin. In the final 30 days of the culture survey and at 9 months, there were no further patients with VRE identified.

Conclusions: Resistant-organism precautions and elimination of patient carriage may be useful measures for controlling the spread of low-prevalence endemic vancomycin-resistant Enterococcus.

Objective: To determine trends in rates of nosocomial infections in Spanish hospitals.

Design: Prospective prevalence studies, performed yearly from 1990 through 1994.

Setting: A convenience sample of acute-care Spanish hospitals.

Participants and Patients: The number of hospitals and patients included were as follows: 1990, 125 hospitals and 38,489 patients; 1991, 136 and 42,185; 1992, 163 and 44,343; 1993, 171 and 46,983; 1994, 186 and 49,689. A core sample of 74 hospitals, which participated in all five surveys and included a mean of 23,871 patients per year, was analyzed separately.

Results: The overall prevalence rate of patients with nosocomial infections in the five studies was as follows: 1990, 8.5%; 1991, 7.8%; 1992, 7.3%; 1993, 7.1%; and 1994, 7.2%. The prevalence rate of patients with nosocomial infection in the core sample of 74 hospitals was 8.9%, 8.0%, 7.4%, 7.6%, and 7.6%, respectively (test for trend, P=.0001). Patients admitted to intensive care units had a 22.8% prevalence rate of nosocomial infection in 1994. The most common nosocomial infections by primary site were urinary tract infection and surgical site infections, followed by respiratory tract infections and bacteremia. More than 60% of all infections were supported by a microbiological diagnosis.

Conclusions: The EPINE project provides a uniform tool for performing limited surveillance of nosocomial infections in most Spanish acute-care hospitals. Its use helps to spread an accepted set of definitions and methods for nosocomial infection control in the Spanish healthcare system. The surveys indicate that the prevalence of nosocomial infections has been reduced over the last 5 years in a core sample of Spanish hospitals.

The laboratory plays a major role in the epidemiology program's efforts to minimize nosocomial infections in healthcare institutions. This article will describe some of the interactions between the laboratory and the epidemiology program, and will identify resources and procedures that the laboratory needs to achieve epidemiologic goals.

Nosocomial infections appear to be increased in patients with acquired immunodeficiency syndrome (AIDS), compared to individuals with asymptomatic infection due to human immunodeficiency virus (HIV). Risk factors for bacterial colonization and infection include immunosuppression, prior treatment with some antibiotics, increased hospitalizations with longer lengths of stay, greater exposure to invasive devices such as indwelling intravenous or urinary catheters, and the degree of immunosuppression. Data suggest that other infectious agents such as Pneumocystis carinii, Mycobacterium tuberculosis, Mycobacterium avium complex, and Cryptosporidium may be acquired in healthcare facilities. Diagnosis and management of nosocomial infections in HIV-infected persons may be complicated by an atypical presentation, increased rates of relapse following treatment, presence of multiple infections, and early discharge from the inpatient setting. Accurate assessment of nosocomial infections and outbreaks in the hospital is complicated by limited data on the risk of transmission of both traditional and unusual pathogens in this population. Furthermore, some patients may acquire nosocomial pathogens during their initial hospitalization and present later with infections that normally would be classified as community acquired. Therefore, there probably is an underestimation of current nosocomial infection rates, and perhaps “hospital-associated” or “healthcare-facility–associated” might be more accurate terms for these infections (Infect Control Hosp Epidemiol 1996;17:304-318).

Public health professionals often are asked to investigate apparent clusters of human health events, or “disease clusters.” A cluster is an excess of cases in space (a geographic cluster), in time (a temporal cluster), or in both space and time. This is part I of an introductory-level review of the analysis of disease clusters for physicians and health professionals concerned with infection surveillance in hospitals. It reviews the status of the field with the hope of expanding the use of cluster analysis methods for the routine surveillance of infectious diseases in the hospital environment.