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R P Wenzel

Publications and source records attributed to R P Wenzel.

At least 181 records · Page 10Linked to original sources
PubMed1989

Coagulase-negative staphylococcal bacteremia. Mortality and hospital stay.

OBJECTIVE: To determine the attributable mortality and the excess length of hospital stay resulting from coagulase-negative staphylococcal bacteremia. DESIGN: Matched historical cohort study. SETTING: Large university-based tertiary care center. PATIENTS: Of 171 patients with hospital-acquired coagulase-negative staphylococcal bacteremia identified by prospective surveillance of nosocomial infections from 1 July 1984 to 30 June 1987, 118 met criteria for the study and were matched to a control patient by age, sex, primary diagnoses, operative procedures, and date of admission. MEASUREMENTS AND RESULTS: Success was achieved in 621 of 650 (96%) variables used for matching. Staphylococcus epidermidis accounted for 92% of the bacteremias. Twenty cases (17%) had evidence of septic shock, and 10 had disseminated intravascular coagulation. The mortality rate in cases was 36 of 118 (30.5%) compared with 20 of 118 (16.9%) in controls. The attributable mortality was 13.6% (95% CI, 4.2 to 22.9) and the risk ratio for dying was 1.8 (95% CI, 1.2 to 2.7; P = 0.006). The median length of stay was 46 days for cases and 37.5 for controls (P = 0.0002). CONCLUSIONS: Coagulase-negative staphylococci, the leading organisms causing hospital-acquired bacteremias, are associated with mortality in excess of that due to the underlying diseases alone. Moreover, they significantly prolong the length of hospital stay. These findings show the importance of coagulase-negative staphylococcal bacteremia in hospitalized patients.

Adolescent↗
PubMed1989

Hospital-acquired pneumonia: overview of the current state of the art for prevention and control.

Hospital-acquired pneumonia affects at least 250,000 patients in U.S. acute care institutions each year and is associated with a crude mortality of approximately 30%. Cases occur at a rate of 0.5-1 per 100 admissions, constituting 10-15% of all nosocomial infections and directly accounting for approximately one-third (10%) of the total mortality. It is likely, therefore, that nosocomial pneumonia represents an important cause of death. No recent large-scale study has systematically examined the true bacterial etiology of hospital-acquired pneumonia utilizing reliable techniques that bypass the oral flora. In the absence of such data, the current approach to therapy based on the examination of sputum is not optimal. Studies that focus on pathogenesis point to the stomach as an important reservoir of infecting organisms. Recent studies suggest that rates of pneumonia can be reduced either by selective decontamination of the digestive tract with antibiotic prophylaxis or by utilizing stress ulcer prophylaxis, which maintains normally low gastric pH. It seems that the time is propitious to examine prehospital determinants of nosocomial infection, with the goal of further preventing these life-threatening events in the hospital.

Bacterial Infections↗
PubMed1989

Nosocomial Legionella micdadei pneumonia: 10 years experience and a case-control study.

Sixteen patients with nosocomial Legionella micdadei pneumonia, diagnosed between 1977 and 1988, were studied retrospectively to define clinical and epidemiological characteristics of the disease. Also, a case-control study was performed comparing the five patients with L. micdadei pneumonia during a cluster of cases in 1982, with uninfected patients with the same underlying diagnoses. No significant differences were noted in the case-control study with regard to age, presence of leucopenia, intensity or duration of immunosuppressive therapy, bed location, duration of hospital stay, frequency of transplant rejection or overall mortality. Legionella micdadei isolates from a sink on the renal transport ward, from hot water storage tanks, and one clinical isolate had identical cellular fatty acid composition. Extensive sampling of other potential sources failed to yield the organism. This indirect evidence suggests potable water as the source of infection.

Cross Infection↗
PubMed1989

Nosocomial gram-negative bloodstream isolates: a comparison of in vitro antibiotic potency.

Nosocomial bloodstream infections add to the morbidity, mortality and length of hospitalization that is attributed to the underlying diseases alone. We have compared the in vitro potency of fifteen antibiotics against 136 isolates from clinically significant nosocomial gram-negative bacteraemias. Ciprofloxacin was the most potent antibiotic and had the broadest spectrum of activity (98% of isolates susceptible, MIC90 range: 0.06-0.5 micrograms ml-1). We subjected all isolates to beta-lactamase induction but antibiotic susceptibility was unaffected by this procedure.

Anti-Bacterial Agents↗
PubMed1989

Hospital stay and mortality attributed to nosocomial enterococcal bacteremia: a controlled study.

A retrospective cohort study of 97 patients identified by prospective hospital-wide surveillance was conducted to determine the length of hospital stay and mortality attributed to hospital-acquired enterococcal bacteremia. The mean duration of hospitalization for cases was 83 days compared with 44 days for matched controls (p = 0.0001). The mortality rate during the study period was 43% among cases and 12% in matched controls (p less than 0.001). Thus the mortality rate attributable to enterococcal bacteremia was 31% and the risk ratio was 4.75. Stepwise discriminant function analysis indicated that the use of vascular catheters and renal dialysis and the presence of immune deficiency were predictors of fatal outcome in cases. Enterococcal bacteremia has become a prominent nosocomial pathogen and is associated with mortality rates well above those expected from the underlying disease.

Adolescent↗
PubMed1989

Use of cellular hydrophobicity, slime production, and species identification markers for the clinical significance of coagulase-negative staphylococcal isolates.

Determining the clinical relevance of coagulase-negative staphylococci isolated from cultures of clinical specimens remains a common dilemma. One hundred eighteen strains of coagulase-negative staphylococci isolated from patients with and without indwelling foreign bodies were characterized with regard to cell-surface hydrophobicity, slime production, and species to determine the predictive value of these phenotypic markers in distinguishing clinically significant from insignificant isolates. The single test with the highest positive predictive value was hydrophobicity (79%). Hydrophobicity and speciation had the greatest combined predictive value of any two tests (89%), and this increased to only 90% when determination of slime production was added. These tests provide additional clinical information when coagulase-negative staphylococci are isolated in culture.

Bacterial Adhesion↗
PubMed1989

Exploration of the microbial anatomy of normal human skin by using plasmid profiles of coagulase-negative staphylococci: search for the reservoir of resident skin flora.

The aerobic bacterial flora of the top 25 layers of the stratum corneum of normal human skin was characterized by sampling glabrous skin with contact plates and analyzing plasmid patterns of coagulase-negative staphylococci (SCN) by agarose gel electrophoresis. The number of colonies of SCN on the skin surface at 12 sites varied from 14 to 838. Removal of five keratinized layers by sequential stripping with cellophane tape reduced the number of colonies by 80% (median; range, 42%-91%). Counts remained constant during removal of 20 additional layers. SCN with six different plasmid patterns were identified at a site on the skin surface. After removal of 25 layers, colonies with a single pattern were clustered in one quadrant of the site. The site was sterilized and covered with a sterile dressing for 18 h. Colonies reappeared in the same quadrant of the site; six of seven had the same pattern seen 18 h previously. Observations at three other sites were similar. Reappearance of the same strain(s) of SCN following sterilization of the site suggests that the reservoir for normal resident skin flora is located below the stratum corneum, perhaps in hair follicles and ducts of sebaceous glands.

DNA, Bacterial↗
PubMed1989

In-vitro susceptibility of nosocomial gram-negative bloodstream pathogens to quinolones and other antibiotics--a statistical approach.

We examined the in-vitro activity of 12 antibiotics against Gram-negative bacillary isolates from 141 distinct episodes of nosocomial bloodstream infection occurring from July 1984 through November 1986. At least ten strains of each of the seven most frequently encountered species were tested. Relative potency was carefully assessed by extending the concentrations from 0.004 to 64 mg/l in microdilution tests performed in duplicate. We estimated MIC50 and MIC90 and, importantly, calculated 95% confidence intervals (CI95) for MIC90. Against all isolates, ciprofloxacin, the most potent antibiotic, had an MIC50 of 0.03 and an MIC90 of 0.13 (CI95 0.11 to 0.16 mg/l). Norfloxacin and enoxacin had MIC90 of 0.50 and 0.71 mg/l, respectively. Imipenem, ceftazidime, aztreonam, and cefoperazone had MIC90 of 1.0, 2.0, 5.3, and 5.7 mg/l, respectively. Both cefotaxime and ceftriaxone had MIC90 of 16 mg/l (CI95 13-19.7 mg/l). For tobramycin, gentamicin and amikacin, the MIC90 values were 1.4, 5.7, and 8 mg/l, respectively. Against Pseudomonas aeruginosa (n = 26), Serratia marcescens (n = 19), and Klebsiella pneumoniae (n = 26), the CI95s about the MIC90 for ciprofloxacin were 0.31-0.81, 0.07-0.23, and 0.04-0.10 mg/l, respectively. For optimal comparison of antibiotics used to treat hospital-acquired bacteraemias, only clinically significant nosocomial bloodstream isolates should be studied with regard to their antibiotic susceptibilities; the isolates should be unique (only one isolate per episode of bacteraemia occurring over a defined period of time); an adequate number of isolates of a particular species should be studied; MICs should be determined over a wide range of concentrations; and both the MIC90 and the CI95 should be reported.

4-Quinolones↗
PubMed1989

Hospital-acquired pneumonia. Attributable mortality and morbidity.

A total of 1,001 consecutive episodes of nosocomial pneumonia in 901 patients was identified by routine surveillance at the University of Virginia Medical Center between 1979 and 1983 (8.6 episodes/1,000 admissions). When only initial episodes were examined, 890 patients comprised the study sample. The overall case fatality rate was 30%. Stepwise logistic regression indicated that time from admission to pneumonia (p = 0.0006), age (p less than 0.0001), prior use of mechanical ventilation (p = 0.0032), and neoplastic disease (p = 0.0062) were associated with mortality. Multiple regression analysis indicated that the factors associated with increased length of hospitalization included posttracheostomy status (p = 0.0001), prior mechanical ventilation (p = 0.0001), immunosuppressive or leukopenic status (p = 0.0009), nasogastric intubation (p = 0.0003), and prior bacteremia (p = 0.0127). A sampled, individually matched cohort study (n = 74 pairs) was conducted to determine the proportion of mortality in cases that was attributable to infections (33%) and to determine excess hospital stay (seven days) among the patients with nosocomial pneumonia. Excess stay was statistically significant (p less than 0.0001), but proportional mortality was only marginally significant (p = 0.0892). Our findings suggest that nosocomial pneumonia accounts for approximately 33% of the crude mortality and contributes significantly to the economic burden associated with prolonged hospitalization.

Cohort Studies↗
PubMed1989

Spontaneous streptococcal gangrenous myositis: survival with early debridement.

Spontaneous gangrenous myositis caused by Streptococcus pyogenes is usually fatal, but no longer uniformly so. There appears to be a spectrum of disease due to beta-hemolytic streptococci, from necrotizing fasciitis to pyomyositis to spontaneous gangrenous myositis. Survival is possible with early surgical debridement, reexploration at 24 to 36 hours, and intensive supportive care.

Aged↗
PubMed1989

Cytomegalovirus and appendiceal perforation in a patient with acquired immunodeficiency syndrome.

We have reported the case of a patient with AIDS who had appendiceal perforation and periappendiceal abscess. Extensive infection with cytomegalovirus was found in the appendix; no other pathogen could be implicated in the perforation. This case emphasizes the broad spectrum of disease due to cytomegalovirus, particularly in patients with AIDS and other immunodeficiencies.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Clinical evaluation of a direct fluorescent monoclonal antibody test for detection of Pseudomonas aeruginosa in blood cultures.

A direct fluorescent monoclonal antibody test (DFA; Genetic Systems Corp., Seattle, Wash.) was evaluated for the detection of Pseudomonas aeruginosa in 178 blood culture broths obtained from 128 patients. The DFA identified 44 (98%) of 45 blood cultures positive for P. aeruginosa and was negative in 131 (98%) of 133 blood cultures which grew gram-negative rods other than P. aeruginosa. Upon further investigation, saline suspensions of the organism from the false-negative blood culture were strongly (4+) DFA positive. The false-positive reactions were not due to cross-reactivity, as shown by lack of DFA staining of the non-P. aeruginosa isolates following subculture to agar media. The specificity of the reagent was further demonstrated by directly staining culture isolates including 10 serotypes of P. aeruginosa (all positive) and 57 selected gram-negative bacilli including eight species of Pseudomonas that were not P. aeruginosa (all negative). DFA staining of blood culture broths was easy to perform and read with minimal background fluorescence. The DFA method can be performed in 50 min and appears promising as a rapid method for the identification of P. aeruginosa bacteremia.

Antibodies, Monoclonal↗
PubMed1989

Coagulase-negative staphylococci. Epidemiology, evaluation, and therapy.

More sophisticated speciation schemes and the application of a variety of epidemiology typing systems have helped to clarify the increasing frequency and changing patterns of nosocomial infections with coagulase-negative staphylococci. The presence of foreign bodies, compromised host defenses, and microbial factors such as slime production may all play important roles in the pathogenesis of these infections. Although coagulase-negative staphylococci are common contaminants in blood cultures, even a single isolation of these organisms warrants careful evaluation. Therapy of these infections may be difficult as phenotypes resistant to multiple antibiotics occur frequently. In the future, both prevention and the development of alternative antimicrobial agents will play important roles in limiting the morbidity and mortality of these infections.

Coagulase↗
PubMed1989

Risk factors for hospital-acquired candidemia. A matched case-control study.

Nosocomial candidemia has become an important infection not only because of an apparently increasing incidence but also because of its high fatality rate. We studied 28 risk factors through a matched case-control study that included 88 pairs of patients hospitalized between July 1983 and December 1986. The strongest single risk factor found in the univariate analysis was the number of prior antibiotics administered: the exposure odds ratio (OR) was 12.50 when patients who received three to five antibiotics were compared with those who received none to two antibiotics. A multiple logistic regression analysis using a conditional likelihood method was performed to evaluate several risk factors simultaneously. The final model selected by a stepwise procedure included the following variables: number of antibiotics received prior to infection (OR, 1.73 per unit increase), isolation of Candida species from sites other than blood (OR, 10.37), prior hemodialysis (OR, 18.13), and prior use of a Hickman catheter (OR, 7.23). It remains to be shown in controlled clinical trials whether limiting the number of antibiotics or instituting prophylaxis and/or early treatment for high-risk patients will reduce the incidence of nosocomial candidemia.

Anti-Bacterial Agents↗
PubMed1988

Removal of nosocomial pathogens from the contaminated glove. Implications for glove reuse and handwashing.

STUDY OBJECTIVE: To evaluate the effectiveness of three different types of handcleansing agents in decontaminating gloved hands that were inoculated with a series of four nosocomial pathogens. DESIGN: A controlled, experimental trial. SETTING: Tertiary care referral center. PATIENTS OR OTHER PARTICIPANTS: Five healthy volunteers participated in all portions of the study. INTERVENTIONS: A standard concentration of one of four representative nosocomial pathogens was placed on the gloved hand, spread, and allowed to dry. One of three different handcleansing agents--a nonmedicated soap, a 60% isopropyl alcohol preparation, or 4% chlorhexidine gluconate--was used to cleanse the gloves, which were cultured using a broth-bag technique. The gloves were then removed and the hands were cultured in a similar manner. MEASUREMENTS AND MAIN RESULTS: The handwashing agents reduced the median log10 counts of organisms to 2.1 to 3.9 after an inoculation of 10(7) colony forming units. The proportion of positive glove cultures for Staphylococcus aureus, 8% to 100%; Serratia marcescens, 16% to 100%; and Candida albicans, 4% to 60% varied greatly after use of the different handcleansers (P less than 0.001), and varied considerably for Pseudomonas aeruginosa, 20% to 48% (P = 0.085). After the gloves were removed, the differences among the observed proportions of hands contaminated with the test organisms varied from 5% to 50%, depending on the handcleansing agent used (P less than 0.001). CONCLUSIONS: In the era of universal precautions these data suggest that it may not be prudent to wash and reuse gloves between patients. Further, handwashing is strongly encouraged after removal of gloves.

1-Propanol↗