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Biomedical subjects

R P Wenzel

Publications and source records attributed to R P Wenzel.

At least 199 records · Page 11Linked to original sources
PubMed1988

Hospital-acquired candidemia. The attributable mortality and excess length of stay.

Between 1977 and 1984, estimates of hospital-acquired bloodstream infections caused by Candida species increased in the United States from 0.5 to 1.5 per 10,000 admissions (National Nosocomial Infection Study data). We examined crude and attributable mortality rates and excess length of stay in 88 closely matched pairs of cases and controls with illnesses occurring between July 1983 and December 1986. The crude mortality rates for cases and controls were 57% and 19%, respectively; thus the attributable mortality rate was 38% with a 95% confidence interval of 26% to 49%. The risk ratio was 2.94 with a 95% confidence interval of 1.95 to 4.43. The median length of stay was 48 days for all cases and 40 days for all controls. An analysis of the length of stay for the 34 matched pairs that survived showed a median of 70 days for cases and 40 days for controls. Candida bloodstream infections represented 10% of all nosocomial bloodstream infections in the period studied at our University Hospital; they are associated with a significant medical and economic burden well above that expected of the underlying diseases alone.

Adolescent↗
PubMed1988

Organization and operation of the hospital-infection-control program of the University of Iowa Hospitals and Clinics.

The University of Iowa Hospitals and Clinics is located in the center of the United States in Eastern Iowa, has 1,000 hospital beds, and is the largest university owned teaching hospital in the country. Over 35,000 patients are admitted each year. The infection control efforts began in 1969 and were broadened in 1976 with the establishment and implementation of the Program of Epidemiology directed by W.J. Hierholzer, Jr., M.D., hospital epidemiologist. Hospital-wide surveillance is routinely performed by three and a half full-time equivalent LPN practitioners who assess problems and evaluate data essential to realistic identification of nosocomial infection rates, implementation of controls and evaluation of control measures. Nosocomial infection surveillance, utilizing modified CDC criteria, has been performed since July 1976. Ward rounds are made by staff, utilizing nursing care and medication Kardex's, microbiology, hematology and X-ray reports. Importantly, the surveillance system is being validated by concurrent prospective surveys to determine the sensitivity and specificity of reporting data. Outbreaks/epidemics of infections, such as Legionella pneumonia, diarrhea of unknown species, and wounds, as well as burns from manufactured changes in cautery grounds, have been identified and controlled before they have become major epidemics. Surveillance has identified one epidemic per 10,000 patients admitted.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross Infection↗
PubMed1988

Prospective evaluation of the Gen-Probe assay for detection of legionellae in respiratory specimens.

A prospective evaluation of a DNA probe assay for detection of Legionella species was performed on 427 consecutive respiratory specimens submitted over an 18-month period. The Gen-Probe assay utilizing both low (greater than or equal to 4.0) and high (greater than 7.0) ratio threshold values was compared to direct fluorescent antibody staining (DFA) as a predictor of isolation of Legionella on culture. The highest sensitivity (63%) was obtained with the lower threshold ratio, but was not significantly different from the result obtained with a threshold ratio of greater than 7.0 (50%, p = 0.722) or DFA results (44%, p = 0.479). The specificity of the DNA probe assay was improved with the high threshold (99%) compared either to the low threshold ratio (95%, p = 0.002) or DFA (97%, p = 0.055). When the DNA probe was compared to DFA and/or Legionella isolation on culture, a significantly lower specificity (97% versus 99%, p = 0.0006) and higher sensitivity (74% versus 37%, p = 0.013) was obtained with a threshold value of greater than or equal to 4.0 than greater than 7.0. Ten of 20 specimens with a DNA probe ratio between 4.0 and 7.0 were DFA positive, although only two were isolated on culture. The DFA assay and both probe threshold ratios have a high negative predictive value when compared to culture. However, only the threshold ratio of greater than 7.0 has a sufficiently high positive predictive value to be useful alone.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA Probes↗
PubMed1988

Bacterial colonization and phlebitis-associated risk with transparent polyurethane film for peripheral intravenous site dressings.

Previous studies of various brands of polyurethane dressings have noted differences in the rates of catheter colonization. We compared Bioclusive transparent polyurethane (TP) dressing with a cotton gauze (CG) dressing on peripheral intravenous (IV) access sites for the incidence of phlebitis, catheter tip colonization, skin colonization, and catheter-related bacteremia. The study, involving 598 ward patients, was case controlled, prospective, and randomized for a period of 4 months. Each patient was entered into the study only once, and all dressings were applied by a member of the IV therapy team. No significant difference was seen for phlebitis rate (TP: 9.8% vs. CG: 7.6%) or catheter tip colonization, defined as greater than 15 colony forming units (CFU) (5.7% vs. 4.4%) by a semiquantitative technique. Cultures of specimens from the skin and catheter tips of the majority of patients (91%) showed no growth. An association was found between those patients with greater than 15 CFU isolated from catheter tips and those with phlebitis (p = 0.022). No documented catheter-related bacteremia occurred in either study group.

Adult↗
PubMed1988

Influence of in vitro susceptibility testing conditions on the anti-candidal activity of LY121019.

LY121019 is a new antifungal antimicrobic that is structurally similar to the lipopeptide agents echinocandin B and aculeacin A. Because of the importance of in vitro test conditions on the activity of other antifungal agents, we studied the effects of inoculum size, time and temperature of incubation, pH, and medium composition on the in vitro activity of LY121019 against Candida albicans, Candida tropicalis, and Candida parapsilosis. LY121019 was highly active against Candida albicans and Candida tropicalis and inactive against Candida parapsilosis. The in vitro activity of LY121019 is marked by a paradoxical dose-response with isolates of Candida albicans and Candida tropicalis and is influenced by choice of inoculum size, time and temperature of incubation, medium composition, and pH. We recommend the use of an inoculum size of less than 10(5) organisms/ml, a defined medium buffered to a pH of 7.0, and incubation at 30 degrees C for 24 hr for future in vitro studies of LY121019.

Amphotericin B↗
PubMed1988

Is there infection control without surveillance?

A brief historical review of hospital surveillance data is presented. It is suggested that routine surveillance of nosocomial infections is important to identify problems for correction, to order priorities, and to influence rates favorably.

Cross Infection↗
PubMed1987

Neonatal intensive care unit bacteremia: emergence of gram-positive bacteria as major pathogens.

An outbreak of nosocomial Staphylococcus epidermidis bacteremia in a neonatal intensive care unit in 1981 was epidemiologically linked to use of Broviac central venous catheters (p = 0.05) and prompted a review of nosocomial infection surveillance data for the previous 6 years, which indicated a striking shift from gram-negative to gram-positive bacteria, especially coagulase-negative staphylococci, as major bloodstream pathogens. In a case-control study with 68 patients with bacteremia between 1979 and September 1981 and 64 control patients, stratified by birth weight, three risk factors were identified: use of Broviac central venous catheters, surgical procedures, and intravenous hyperalimentation. The risk factors varied with the birth weight category. In the group of cases and controls with birth weights less than 1500 gm, only the use of Broviac catheters, which are usually left in the superior vena cava for several weeks, was associated with subsequent bacteremia (odds ratio = 7.1, p = 0.001). These observations, as well as the temporal association of the introduction of Broviac catheters with the subsequent shifts in causes to gram-positive organisms, suggest that the long-term indwelling vascular access devices contributed greatly to the changing pattern.

Catheters, Indwelling↗
PubMed1987

Emergence of coagulase negative staphylococci as major nosocomial bloodstream pathogens.

Over an eight year period, 1975 to 1982, 1,843 nosocomial bloodstream infections were identified by routine prospective surveillance at the University of Virginia Hospital (106/10,000 admissions). Despite a decline in overall bloodstream infection rates during the study period (P = .085), bloodstream infections due to gram positive organisms increased from 29 (1975-1978) to 43/10,000 (1979-1982), (P less than 0.001). Notably, rates for coagulase negative staphylococci increased from 5.2 (1975-1978) to 12.4/10,000 (1979-1982), (P less than 0.001). In 1982, coagulase negative staphylococci accounted for 17% of all bloodstream infections and were the most frequently isolated pathogens. Sixty-four percent of patients with coagulase negative staphylococci were in critical care units versus 41% with other bloodstream infections (P less than .05). The recognition of coagulase negative staphylococci as significant bloodstream pathogens markedly alters the clinician's approach to nosocomial septicemia.

Coagulase↗
PubMed1987

A measurement of the efficacy of nosocomial infection control using the 95 per cent confidence interval for infection rates.

From 1981 through 1985, the authors studied the changes in monthly nosocomial infection rates at the University of Virginia Hospital in Charlottesville, Virginia using the 95% confidence interval for infection rates as a marker of the efficacy of infection control activities. For a 99-month baseline period, monthly infection rates were calculated and the 95% confidence interval was established. In the 60 study months, each monthly rate was compared with the 95% confidence interval for that particular month. At the end of each study year, the monthly infection rates were incorporated into the existing confidence interval. Of 60 monthly rates during the study period, 30 were below the confidence interval (p less than 0.00001), two were above the confidence interval (p = 0.23), and 28 were within the confidence interval. Since there was no reduction in surveillance activity, patient case-mix index, or laboratory sensitivity for organism recovery, these results suggest that monthly nosocomial infection rates at this hospital have decreased when compared with the baseline period. The use of the 95% confidence interval may provide a measure of the efficacy of infection control activities, suggest temporal intervals requiring more intensive infection surveillance, and provide a method for examining the variability in monthly infection rates.

Cross Infection↗
PubMed1987

Etiologic organisms as independent predictors of death and morbidity associated with bloodstream infections.

We studied 385 episodes of nosocomial bloodstream infections occurring over 45 months to ascertain if the etiologic organisms were independent predictors of death and morbidity. Independent predictors of death included respiratory failure, oliguria, metabolic acidosis, hypotension, increased age, antibiotic therapy in cases where susceptibility data were unknown, and infection with Pseudomonas aeruginosa. If parameters associated with septic shock were excluded, increased age, severity of disease, and infection with Candida spp. or P. aeruginosa predicted death. Infection with P. aeruginosa, Enterococcus, and Klebsiella pneumoniae predicted hypotension; severity of disease, polymicrobial infection, and infection with Candida spp., Enterococcus, Enterobacter, or Serratia marcescens predicted oliguria; infection with Candida spp. or P. aeruginosa, increased age, severity of disease, and inability to meet hospital financial obligations without assistance predicted respiratory failure. Inability to meet hospital financial obligations without assistance and severity of disease predicted hypothermia; infection with Candida spp. or P. aeruginosa and sex (male) predicted metabolic acidosis.

Acidosis↗
PubMed1987

Rabies pre-exposure prophylaxis using intradermal human diploid cell vaccine: immunologic efficacy and cost-effectiveness in a university medical center and a review of selected literature.

The authors studied the antigenicity of intradermal human diploid cell rabies vaccine administered to 40 laboratory workers considered to be at-risk at the University of Virginia Medical Center. A 1-year postvaccination serology was determined for 20 of those 40, all of whom demonstrated an antirabies titer greater than or equal to 1:50 by the raped fluorescent focus inhibition test. By 2 years' postvaccination, 5 of 40 subjects had "unprotective levels" (less than 1:5), whereas 35 had titers greater than or equal to 1:5, and none had a titer greater than or equal to 1:50. Booster doses given to four subjects whose titers had declined produced a 1-month postvaccination antirabies titer greater than or equal to 1:50 in all cases. Vaccine administration by the intradermal rather than the intramuscular route resulted in a cost savings of $120 (U.S.) per employee. This data indicate that the intradermal administration of human diploid cell vaccine for rabies pre-exposure prophylaxis achieves an immunologic response thought to be protective while providing a substantial cost savings when compared with the intramuscular route of administration. Those who receive primary pre-exposure rabies vaccination should have serologic confirmation of immunologic protection every 2 years with a booster dose given to subjects demonstrating a titer less than 1:5.

Adolescent↗
PubMed1987

Gram-negative bacilli as nontransient flora on the hands of hospital personnel.

The possibility that gram-negative bacilli (GNB) are part of the nontransient flora on hands was examined by using a broth rinse technique to detect low titers of GNB after a hygienic hand wash with soap and water. A total of 100 nurses who had direct patient contact and 40 controls without patient contact had a similar rate of recovery of GNB (46 and 55%, respectively). GNB persisted on the hands of 10 nurses throughout five successive hand washes with soap and water. Hand cultures were obtained daily from 12 nurses before and after a work shift in a surgical intensive care unit. GNB were recovered from 57% of individuals before patient contact and from only 24% after the work shift. Nontransient GNB on the hands of hospital personnel are a potential reservoir for hospital strains, and patient contact is not an obvious source for the acquisition of nontransient GNB.

Acinetobacter↗
PubMed1987

The epidemiology of Legionella pneumophila infections.

The study of outbreaks of Legionella pneumophila has been essential in understanding the organism, the disease, and its pathogenesis. Early epidemics defined the clinical spectrum: Pontiac fever is an acute, self-limited, febrile illness with an attack rate of 95% to 100% and an incubation period of 36 hours. In contrast, legionnaires' disease is a life-threatening bronchopneumonia with an attack rate of 2% to 7% and an incubation period of two to ten days. Three times as many males as females are affected with legionnaires' disease, and age, cigarette smoking, and chronic medical disease (particularly immunosuppression) appear to be separate risk factors. Furthermore, L pneumophila is responsible for approximately 1% to 3% of community-acquired pneumonias, 13% of those acquired in the hospital and as many as 26% of atypical pneumonias. Diverse environmental reservoirs have been identified, including cooling systems, potable or domestic water systems, respiratory therapy devices, industrial coolants, and whirlpool spas. Hot water temperature, stagnant water, sediment, and the presence of other microorganisms are important factors in the amplification of the Legionellaceae. Although airborne transmission has been widely suggested, aspiration may be an important mode in certain patients. Regional and national surveillance may identify common sources and allow the introduction of early control measures. The latter have included primarily pulse and continuous hyperchlorination and super-heating hot water systems to 50 to 60 degrees C. Experimental data suggest that ozone and UV light may be useful in the future. Additionally, cooling towers and evaporative condensers have been decontaminated and maintained with a variety of biocides. The prevention of outbreaks requires thoughtful planning, redesign, and good engineering practices.

Disease Outbreaks↗