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Biomedical subjects

R P Wenzel

Publications and source records attributed to R P Wenzel.

At least 127 records · Page 7Linked to original sources
PubMed1993

Secular trends in rates and etiology of nosocomial urinary tract infections at a university hospital.

To examine changing trends in the microbial etiology of nosocomial urinary tract infections, we reviewed culture data from a surveillance database for the calendar years 1982 to 1991. The overall rates of nosocomial urinary tract infections have increased significantly during the last decade from 2.63 per 1,000 patient-days to 4.35 per 1,000 patient-days (p = 0.0023). For specific isolates the rates of yeasts, Klebsiella pneumoniae and group B streptococcus have increased significantly during the last decade. The rates of Escherichia coli, Proteus species and Pseudomonas species have all decreased. Analysis of these secular trends can provide important information relating to the etiology of nosocomial urinary tract infections. It is likely that antibiotic "pressure" has influenced the microbiology of infections and that altered case-mix would explain much of the increase in rates. However, the multiple reasons for these secular trends and their precise contributions to them are unknown.

Bacteria↗
PubMed1993

Trends in gram-positive bloodstream organism resistance: a seven-year audit of five glycopeptides and other drugs at a large university hospital.

Gram-positive pathogens (n = 525) isolated from bloodstream infections were tested by a reference broth microdilution method to establish antibiotic susceptibility trends (1985 to 1991). Cefazolin, ciprofloxacin, gentamicin, novobiocin, oxacillin, rifampin, teicoplanin, vancomycin, trimethoprim/sulfamethoxazole, daptomycin and two investigational glycopeptides (LY264826 and MDL62873) were investigated. Strains were selected without bias (first two isolates each month/species; no patient duplicates) as follows: 132 Staphylococcus aureus, 129 Staphylococcus epidermidis, 72 Staphylococcus haemolyticus, 130 Enterococcus faecalis and 62 other enterococci. All isolates were susceptible to vancomycin and teicoplanin except for Staphylococcus haemolyticus which had a resistant teicoplanin MIC90 of 64 micrograms/mL. The susceptibilities to vancomycin and teicoplanin were unchanged over the monitored period. Daptomycin, LY264826 and MDL62873 also demonstrated consistent activity; MDL62873 being superior with a MIC90 of 0.12 micrograms/mL. In 1990-1991 a significantly increased resistance to ciprofloxacin was observed among oxacillin-resistant strains of staphylococci. Our data suggest that the emergence of invasive vancomycin-resistant strains in Gram-positive isolates remains a rare phenomenon. However, we have experienced an emergence of numerous ciprofloxacin-resistant strains among staphylococci that precludes its empirical use at our institution.

Anti-Bacterial Agents↗
PubMed1993

Restriction endonuclease analysis of plasmid DNA from methicillin-resistant Staphylococcus aureus: clinical application over a three-year period.

OBJECTIVE: To investigate trends in plasmid types of methicillin-resistant Staphylococcus aureus over a 3-year period and determine the clinical impact of plasmid typing. DESIGN: Restriction endonuclease analysis of plasmid DNA (REAP) was used to type 270 clinical isolates. SETTING: A Veterans Affairs Medical Center. RESULTS: Forty-four different REAP types were identified and, of these, 23 appeared only once. Types designed as V1 and V2 were more commonly found in nosocomial cases than in community-acquired cases (p < .05); whereas the K and D types were more common in isolates from community-acquired cases (p < .05). In 30 (11%) isolates, no plasmid was detected. When combined with epidemiological data, REAP typing revealed 4 small outbreaks that would have been missed using traditional epidemiological methods alone. In large outbreaks involving 10 or more cases, REAP typing data revealed unsuspected patterns of transmission. CONCLUSIONS: Multiple plasmid types were present in this endemic setting. Restriction endonuclease analysis of plasmid DNA was a practical and valuable adjunct to traditional epidemiological methods.

DNA Restriction Enzymes↗
PubMed1993

Trends in antimicrobial utilization at a tertiary teaching hospital during a 15-year period (1978-1992).

BACKGROUND: Antimicrobials are a major part of hospital pharmacy budgets and must be considered in resource planning and spending projections. Logically, trends in antimicrobial usage should be linked to trends in resistant pathogens. OBJECTIVE: To examine long-term trends in antimicrobial use over a 15-year period (1978 to 1992) and contrast them with changes in pathogens causing nosocomial bacteremia. SETTING: A 900-bed, tertiary care teaching hospital. METHODS: Pharmacy records were reviewed to identify parenteral antimicrobial agents administered to adult inpatients. Results were expressed in average daily adult doses per 1,000 patient days. RESULTS: Chloramphenicol use decreased, while use of penicillin G, antistaphylococcal penicillins, first-generation cephalosporins, and aminoglycosides remained relatively stable. In contrast, there was a sharp increase in the use of second- and third-generation cephalosporins (7-fold and 6.5-fold increase, respectively), vancomycin (161-fold increase), metronidazole (32-fold increase) and amphotericin B (35-fold increase). The proportion of nosocomial bacteremias due to methicillin-resistant gram-positive bacteria rose, but gentamicin resistance in gram-negatives remained at low levels. During the past 14 years, the percentage of patients receiving at least one parenteral antimicrobial rose from 23% to 44%. Among patients receiving antimicrobials, the average number of different agents used per patient increased from 1.8 to 2.1. CONCLUSIONS: If newer agents were available, use of older agents usually declined. If newer alternatives were not available, use of older agents rose sharply. The increased use of antimicrobials in adults was related to the expanded proportion of patients receiving these agents.

Adult↗
PubMed1993

Outbreak of Pseudomonas aeruginosa infections in a surgical intensive care unit: probable transmission via hands of a health care worker.

Pseudomonas aeruginosa was isolated from nine patients (16.2 isolations/1,000 patient-days) in a surgical intensive care unit during an outbreak in November 1990; this rate of isolation was three times higher than that noted previously on this unit. Three patients were infected with the same strain, as defined by identical serotypes, pyocin types, and contour-clamped homogeneous electric field (CHEF) electrophoresis patterns of digested genomic DNA. The hands of 80 health care workers were cultured, and a strain of P. aeruginosa identical to that infecting the three patients was isolated from the hands of a nurse providing care to all three. Environmental surfaces, medical devices, and ward stock supplies were cultured; none of these cultures yielded this strain. No clusters of infection with this strain or other strains of P. aeruginosa were observed after compliance with hand-washing and universal precautions was reemphasized. Thus this outbreak was linked to the carriage of P. aeruginosa on the hands of a health care worker. It could not be determined definitively whether this carriage was the source of the cluster or a consequence of it. However, the geographic and temporal clustering of carriage with an outbreak due to a strain of an apparently identical molecular type underlines the importance of routine hand washing between contacts with different patients.

Adult↗
PubMed1993

Tumor necrosis factor and the therapeutic potential of anti-tumor necrosis factor antibodies.

OBJECTIVE: To review the relationship of tumor necrosis factor (TNF) to clinical sepsis and the clinical potential of anti-TNF therapy in decreasing morbidity and mortality rates due to sepsis. DATA SOURCES: The international English language literature was reviewed, including animal studies and human clinical trials regarding TNF, anticytokine therapy, and sepsis. STUDY SELECTION: Studies which characterized the immunopharmacologic interactions between TNF and sepsis were emphasized. DATA EXTRACTION: This study specifically focused on experiments and clinical trials that directly involve the activity of TNF or anti-TNF antibodies, particularly but not limited to data derived from septic patients. DATA SYNTHESIS: The relationship between TNF and sepsis is described. Clinical aspects of anti-TNF therapy (timing, empiric use) are discussed. Phase I, II, and III trail of anti-TNF antibodies in clinical trials are reviewed. CONCLUSIONS: Current clinical strategies for sepsis therapy are only partially effective. Recent immunopharmacologic advancements have resulted in the identification of TNF as a pivotal proinflammatory cytokine mediator of sepsis. Animal studies demonstrate that anti-TNF therapy protects animals from the morbidity and mortality of sepsis. Phase I clinical studies of anti-TNF antibodies demonstrate the safety of monoclonal antibody therapy. The therapeutic application of anti-TNF antibodies in sepsis trials is ongoing.

Animals↗
PubMed1993

An outbreak of hepatitis A among health care workers: risk factors for transmission.

OBJECTIVES: The purpose of this study was to investigate a nosocomial outbreak of hepatitis A that occurred in the burn treatment center of a referral hospital. METHODS: Retrospective cohort and case-control studies were performed to determine acquisition rates and risk factors for transmission. Adjusted infection rates were calculated by week of exposure. A case-control study was conducted to determine potential mechanisms for nosocomial acquisition. Recently infected health care workers were defined as case patients; exposed, serosusceptible health care workers without infection served as controls. RESULTS: The outbreak of hepatitis A affected 11 health care workers and 1 other burn patient (1 secondary patient case). All 11 health care workers became ill after the admission of a man and his 8-month-old son who developed hepatitis A while in the hospital. The cumulative incidence risk ratio was elevated for health care workers caring for either the infant or the father during the same week of exposure. The case-control study implicated the behavior of eating on the hospital ward as the single most important risk factor for infection. CONCLUSION: Inadequate hand-washing and subsequent oral contamination appear responsible for the outbreak. Hospitals may witness other institutional outbreaks if health care workers regularly eat on the wards.

Adult↗
PubMed1992

Comparative efficacy of alternative hand-washing agents in reducing nosocomial infections in intensive care units.

BACKGROUND: Effective hand-washing can prevent nosocomial infections, particularly in high-risk areas of the hospital. There are few clinical studies of the efficacy of specific hand-cleansing agents in preventing the transmission of pathogens from health care workers to patients. METHODS: For eight months, we conducted a prospective multiple-crossover trial involving 1894 adult patients in three intensive care units (ICUs). In a given month, the ICU used a hand-washing system involving either chlorhexidine, a broad-spectrum antimicrobial agent, or 60 percent isopropyl alcohol with the optional use of a nonmedicated soap; in alternate months the other system was used. Rates of nosocomial infection and hand-washing compliance were monitored prospectively. RESULTS: When chlorhexidine was used, there were 152 nosocomial infections, as compared with 202 when the combination of alcohol and soap was used (adjusted incidence-density ratio [IDR], 0.73; 95 percent confidence interval, 0.59 to 0.90). The largest reduction with chlorhexidine was in gastrointestinal infections (IDR, 0.19; 95 percent confidence interval, 0.05 to 0.64). When chlorhexidine was available, the rates of nosocomial infection declined in each of the ICUs, and health care workers washed their hands more often than when alcohol and soap were used (relative risk, 1.28; 95 percent confidence interval, 1.02 to 1.60). The total volume of alcohol and soap used was 46 percent that of chlorhexidine (P less than 0.001). CONCLUSIONS: A hand-disinfection system using an antimicrobial agent (chlorhexidine) reduces the rate of nosocomial infections more effectively than one using alcohol and soap. The improvement may be explained at least in part by better compliance with hand-washing instructions when chlorhexidine was used.

1-Propanol↗
PubMed1992

Nosocomial pneumonia in patients having bone marrow transplant. Attributable mortality and risk factors.

The authors performed a matched historic cohort study to determine the attributable mortality and risk factors for nosocomial pneumonia in bone marrow transplant (BMT) recipients. All patients with nosocomial pneumonia at a university tertiary care center were identified by a prospective surveillance system between 1980 and 1988. Control patients were selected from the population of BMT patients. The crude mortality for 55 patients with nosocomial pneumonia was 74.5% (95% confidence interval [CI95], 63% to 86%). The excess or attributable mortality was 61.8% (CI95, 43.7% to 80%). Aspergillus species represented the most frequent etiologic agent in this series, causing 20 of the 55 (36%) episodes. The attributable mortality of Aspergillus species pneumonia alone was 85% (CI95, 58.6% to 100%). For death in the hospital, the risk ratio for all 55 case patients relative to control patients was 9.5 (CI95, 4.1 to 22.1). To evaluate several risk factors simultaneously, a multiple logistic regression analysis using a conditional likelihood method was performed. A mathematical model with three variables best predicted nosocomial pneumonia in our patients: the occurrence of other nosocomial infections before the diagnosis of pneumonia, allogeneic BMT, and the use of methotrexate. The presence of other nosocomial infections before the diagnosis of pneumonia remained a significant independent risk factor, with an odds ratio of 13.27 (CI95, 2.51 to 70.2) after adjustment for the use of methotrexate and allogeneic BMT. Most importantly, effective methods for preventing nosocomial pneumonias in BMT recipients will have an enormous effect on crude mortality.

Bone Marrow Transplantation↗
PubMed1992

Restriction endonuclease analysis of Staphylococcus aureus plasmid DNA from three continents.

Staphylococcus aureus isolates (n = 1201) from 20 centers in Europe, the USA and Brazil were evaluated for the presence of epidemiologic markers. Plasmid typing and restriction endonuclease analysis of plasmid DNA confirmed the presence of an apparently identical plasmid in 13% of clinical isolates. The plasmid was recovered from all 20 hospitals studied, with an overall frequency of greater than 10% on each of the three continents. Since relatively few staphylococcal plasmids may be shared by epidemiologically unrelated strains, there are inherent limitations to this otherwise useful technique. Additionally, these data demonstrate the importance of including unrelated strains of Staphylococcus aureus from the local region as controls when molecular typing methods are performed.

Brazil↗
PubMed1992

A new standard for sterility testing for autoclaved surgical trays.

Sterility testing on autoclaved surgical trays provides scientific information on the duration for which an item can be safely stored. Previous studies were performed by sampling at various time-points after storage and did not take into account potential injuries (moving, lifting etc.) to these trays as they occur in a clinical setting. A standardized protocol was developed by an expert panel based on events which were frequently observed in the Central Sterilization area. We tested 600 samples in 100 surgical trays that were moved and transported according to the standardized protocol. Moved surgical trays were contaminated in 8.3% of tests, a figure much higher than that reported by previous studies. These data suggest that current standards for sterility testing of autoclaved surgical trays can be improved by the addition of event-related testing.

Central Supply, Hospital↗
PubMed1992

Postdischarge surveillance for nosocomial wound infection: a brief review and commentary.

Escalating medical care costs during the last decade have resulted in shorter hospital stays and higher volumes of outpatients surgical procedures. As a result, the proportion of nosocomial surgical wound infections manifesting after discharge will increase. We performed a literature review to assess the current state of the art of postdischarge surveillance for nosocomial wound infection. From 20% to 70% of postoperative surgical site infections do not become apparent until after the patient's discharge, resulting in serious underreporting of true rates. Infections in outpatients are not being identified efficiently. Institutions using self-reporting methods report a low validity for these methods. The Centers for Disease Control and the Joint Commission for the Accreditation of Healthcare Organizations currently have no strong guidelines on the subject. Since valid postdischarge surveillance may become a necessity for a quality infection control program, new national recommendations are needed.

Ambulatory Surgical Procedures↗