We studied hospital costs associated with healthcare worker (HCW) respiratory protection and respirator fit-testing programs recommended by the Centers for Disease Control and Prevention (CDC) and mandated by the Occupational Safety and Health Administration to decrease nosocomial or occupational Mycobacterium tuberculosis (TB).

The number and cost of high-efficiency particulate air (HEPA)-filter and dust-mist (DM) respirators for 1989 to 1994 were obtained from study hospital purchasing departments, and the costs of HCW fit-testing and education programs for 1994 were estimated from information provided by infection control practitioners. Costs of N-class respirator programs were estimated for study hospitals using retrospective cost analysis and an observational study.

Four urban hospitals with, and one rural community hospital without, documented nosocomial or occupational transmission of multidrug-resistant TB.

During the study period, four of five hospitals introduced HEPA and DM respirators and respirator education and fit-testing programs. Median costs in 1994 were $83,900 (range, $2,000-$223,000) for respirators and $17,187 (range, $8,736-$26,175) for respiratory fit-testing programs. The projected median annual cost of N95 respirators was $62,023 (range, $270-$422,526).

Compliance with CDC TB guidelines may require a substantial investment. However, outlays for respirators and education and fit-testing programs are more reasonable than would be suggested by analyses that estimated the costs of preventing one case of nosocomial TB

To use DNA fingerprinting to characterize nosocomial spread of Mycobacterium tuberculosis following hospitalization of a patient with acquired immunodeficiency syndrome and active pulmonary tuberculosis, for whom respiratory isolation was not initiated promptly.

Epidemiological investigation.

A tertiary-care medical center in Tennessee.

Patients and healthcare workers potentially exposed to the infectious patient in 1992.

Of 172 healthcare workers exposed, 35 (20%) were judged to have acquired tuberculous infection. Risk of acquisition was greatest for nurses and medical receptionists. Active tuberculosis later developed in one healthcare worker and one hospitalized patient. Nosocomial transmission was supported by epidemiological evidence and DNA fingerprinting. The outbreak strain of Mycobacterium tuberculosis differed from other isolates at this hospital, but its DNA hybridization pattern was highly similar to that of the multidrug-resistant outbreak strain W that has been prevalent in New York City, suggesting a common strain ancestry. However, the Tennessee isolates were susceptible to all first-line antituberculous agents.

This report suggests the possibility that a molecular characteristic(s) shared by these successful outbreak strains is associated with increased transmissibility or pathogenicity and emphasizes the need for continued vigilance for tuberculosis in the nosocomial setting.

To determine the frequency of, and risk factors for, infections associated with intra-arterial catheters used for cancer chemotherapy.

Between September 1992 and September 1995, we conducted a surveillance study of all 807 intra-arterial catheters placed for chemotherapy at our center. The insertion site was disinfected with povidone iodine and alcohol, and the arterial catheter was placed using maximal sterile barrier precautions. Upon removal, all intravascular segments were submitted for semiquantitative culture.

No episodes of catheter-related bloodstream infection (95% confidence interval [CI95], 0%-1.6%) were observed. However, the risk of colonization (>15 colony-forming units) of arterial catheters was 15% (CI95, 12%-17%). Retrospective risk-factor analysis conducted on 224 intra-arterial catheters placed for chemotherapy in 1993 showed that colonization was associated significantly with duration of catheterization (median of 1 day for culture-negative catheters vs median of 4 days for culture-positive catheters, P<.001). Age, gender, prior radiotherapy, underlying cancer, neutropenia, and hypoalbuminemia were not associated with catheter colonization.

Intra-arterial catheters for cancer chemotherapy placed under maximal sterile barrier precautions for a short period of time are associated with a very low risk of bloodstream infection.

To describe investigations into an increase in hemodialysis-related bacteremia that occurred in our hospital in the first 6 months of 1996.

Hemodialysis unit in a tertiary-care medical center.

Prospective surveillance for hemodialysis bacteremia has been performed for several years. Cases that occurred in 1995 were compared to cases in the first 6 months of 1996. Unit data on dialysis runs and method of dialysis access were used to calculate rates. Nested polymerase chain reaction (PCR) was used to type 18 Staphylococcus aureus isolates from 1996. A case-control study comparing 80 randomly selected hemodialysis patients from 1995 and 1996 was performed to examine infection risk factors.

The hemodialysis bacteremia rate was 1.2 per 1,000 runs in 1995 and 2.8 per 1,000 in the first 6 months of 1996 (P=.0009). The 25 cases in 1995 and 32 in the first half of 1996 were similar in age, gender, means of vascular access, and micro-bial etiology. Central venous catheter (CVC) access accounted for >90% of cases in both time periods. S aureus was the most common microbial etiology (53% of the 1996 cases). PCR typing of S aureus isolates from 1996 demonstrated five different strains, the most common having six isolates. The use of CVCs as a means of vascular access abruptly increased in the unit in January 1996, from <30% of dialysis runs in 1995 to >40% in 1996 (P<.001), associated with structural changes in healthcare delivery in the region resulting in delays in performing surgical procedures, such as creation of vascular grafts and fistulae.

A marked increase in hemodialysis bacteremia occurred in 1996, associated with increased reliance on CVCs for vascular access in hemodialysis patients during a period of healthcare restructuring.

To describe the effect of infection control interventions on the incidence of vancomycin-resistant enterococci (VRE), the utility of pharyngeal cultures for surveillance for VRE colonization, and the cost of barrier precautions.

Evaluation of the occurrence of VRE infection or colonization, rates of vancomycin use, results of surveillance cultures before and after interventions, and the cost of increased barrier precautions.

University of Massachusetts Medical Center, a 347-bed tertiary-care teaching hospital with eight intensive-care units, one burn unit, and one bone marrow transplant unit.

Patients in the intensive-care units and staff who were involved with patients colonized or infected with VRE.

Infection control interventions included placement of patients with VRE in private rooms, strict contact isolation, cohorting of patient and nursing staff, prohibiting of equipment sharing, and monitoring of compliance with the vancomycin restriction policy, with hand washing, and of the adequacy of environmental cleaning. Both rectal and pharyngeal cultures were obtained from patients at the beginning of the outbreak, and the utility of pharyngeal cultures was evaluated. The cost of barrier precautions was estimated by comparing the cost of glove and gown use before and after the outbreak began.

The interventions decreased the number of new cases of VRE, but total eradication of VRE was not achieved. Compliance with the room-cleaning protocol was 91% (141/155 observations). Hand washing following interaction with patients who were not in isolation was 51%, vs 100% for patients in isolation. Overall, handwashing compliance was 71% (319/449): 56% (130/231) for physicians and 86% (187/218) for nurses (P<.0001). The mean number of doses of vancomycin dispensed per 1,000 patient days decreased from 145 to 114 per 1,000 patient days (P<.001). Compliance with vancomycin-use guidelines was 85%. Forty-six (77%) of 60 surveillance rectal swabs yielded enterococci, as compared to only 4 (11%) of 36 pharyngeal cultures (P<.0001). Expenses on glove and gowns alone increased by over $11,000 per year since the epidemic began.

Implementation of the various infection control measures did not eradicate VRE cases from the hospital. Rectal cultures were more useful than pharyngeal cultures for surveillance of VRE. Controlling VRE epidemics can be costly.

To reduce the use of amoxicillin-clavulanate after high-resistance rates in Escherichia coli were detected.

Intervention study; the interventions were introduced successively over a 4-year period while closely monitoring the resistance patterns.

A 260-bed acute-care hospital in Switzerland.

Introduction of therapeutic guidelines for specific departments or indications, which proposed alternative antibiotics to amoxicillin-clavulanate. The perioperative prophylactic use of amoxicillin-clavulanate was eliminated completely.

The absolute amount of amoxicillin-clavulanate consumed decreased by 23%, from 24.8 g per 100 patient days in 1992 to 18.5 g per 100 patient days in 1995. The number of courses, a parameter that takes the prophylactic use into account, decreased by 62% from 2.3 per 100 patient days in 1992 to 0.9 per 100 patient days in 1995. The percentage of sensitive strains increased from 54.9% (n=512) in 1992 and 54.0% (n=506) in 1993 to 72.1% (n=546) in 1994 and 83.1% (n=668) in 1995. No major changes were detected for other antimicrobials, such as cotrimoxazole, tetracycline, or cefuroxime, used in this 4-year period.

A decrease in the use of amoxicillin-clavulanate was followed by an increase in susceptibility of E coli to it. It was not possible to prove a causative relationship. Only a temporal association was discovered. The reduction of the use of amoxicillin-clavulanate was achieved through the implementation of treatment guidelines, facilitated through a close collaboration among the clinical pharmacists, the infection control practitioner, the microbiology laboratory, and the physicians in charge of the respective departments.

To compare a surveillance definition of nosocomial bloodstream infections requiring only microbiology data to the Centers for Disease Control and Prevention's (CDC) current definition.

Six teaching hospitals.

We classified a representative sample of 73 positive blood cultures from six hospitals growing common skin contaminant isolates using a definition for bacteremia requiring only microbiology data and the CDC definition for primary bloodstream infection (National Nosocomial Infections Surveillance [NNIS] System review method). The classifications assigned during routine prospective surveillance also were noted, and the time required to classify isolates by the two methods was compared.

Among 65 blood cultures growing common skin contaminant isolates obtained from adults, the agreement rate between the microbiology data method and the NNIS review method was 91%. Agreement was significantly poorer for the eight blood cultures growing common skin contaminant isolates obtained from pediatric patients. The microbiology data method requires approximately 20 minutes less time per isolate than does routine surveillance.

A definition based on microbiology data alone yields the same result as the CDC's definition in the large majority of instances. It is more resource-efficient than the CDC's current definition

To demonstrate the limits of comparison of national prevalence rates of nosocomial infections.

Critical analysis of prevalence rates and methods of the Nosocomial Infections in Germany (NIDEP) study and other prevalence surveys with particular attention to the selection of patients, the qualification and training of the investigators, and the methods of identifying nosocomial infections.

The lowest prevalence rate was found in Germany (3.5 %), the highest in Belgium (9.3 %). These differences may not be accurate, because variations in methods allow for differing explanations.

Because of numerous methodological factors, comparison of infection rates between countries should be avoided. In contrast to other prevalence studies, the methodology of the German-NIDEP study permits registration of only certain infections, which is the main reason for the low rate.

To determine whether an investigator effect remained on the first German study on the prevalence of nosocomial infections Nosokomiale Infektionen in Deutschland Erfassung und Prävention (NIDEP), despite extensive validation efforts.

Two validation methods were applied: bedside validation and validation by case studies. In both cases, the results of the four investigators were compared with the diagnosis of gold standard observers.

Validation measures were applied before, intermittently, during, and at the end of the surveillance period in 72 acute-care hospitals with 14,966 patients.

The overall sensitivity in the bedside-validation periods was 89.0%; the overall specificity was 99.5%. For validation by case studies, overall sensitivity was 95.6%, and overall specificity was 92.8%. At the end of the surveillance, a remarkable investigator effect was found.

Despite validation results that were assessed as satisfactory, based on available literature, an investigator effect was observed. This underlines the need for data validation and the formulation of recommendations for data validation. Clarification of the Centers for Disease Control and Prevention criteria for pneumonia and primary bloodstream infection and the inclusion of some diagnostic test results may reduce or prevent an investigator effect in future studies.

To identify risk factors for Klebsiella pneumoniae bloodstream infections (BSI) in neonates in a hospital in the Kingdom of Saudi Arabia (KSA).

Two case-control studies among hospitalized neonates during February 15-May 14, 1991, and a procedural and microbiological investigation.

Hospital A, a maternity and children's hospital in KSA.

Case patients had a blood culture positive for K pneumoniae after >2 days of hospitalization and had no evidence of a nonblood primary site of infection.

When the 20 case patients were compared with controls, hospitalization in a critical-care unit (odds ratio [OR], 5.5; 95% confidence interval [CI95], 1.20-51.1; P=.03) was identified as a risk factor. When the case patients were compared with a second set of controls matched by critical-care status, receipt of a particular intravenous fluid (D10%/0.2NS; OR, 11.0; CI95, 1.42-85.2; P=.009) or a blood product (OR undefined; P=.04) were identified as risk factors. Infusates were administered via umbilical catheters for most case and control patients (19/20 vs 15/20, P>.05); catheters were manipulated more frequently in patients in criticalcare units. Umbilical catheter tip, skin, or mucus membrane K pneumoniae colonization occurred in 47% and 53% of evaluated case and control patients, respectively. Available K pneumoniae isolates from blood cultures and colonization sites had identical antimicrobial susceptibility patterns. Emphasis on handwashing, careful preparation and administration of infusates, and aseptic technique for catheter insertion, maintenance, and manipulation was temporally associated with resolution of the epidemic.

This outbreak was probably due to infusion therapy practices that led to BSI in nursery patients colonized with K pneumoniae. Both catheter-related infections and extrinsic contamination of infusates may have occurred. Hospital personnel should be aware of their potential to spread nosocomial pathogens from person to person and should implement Centers for Disease Control and Prevention recommendations to decrease nosocomial BSIs.