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Biomedical subjects

R P Wenzel

Publications and source records attributed to R P Wenzel.

At least 325 records · Page 18Linked to original sources
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The use of biotyping and DNA fingerprinting in typing Candida albicans from hospitalized patients.

The application of typing procedures for the purpose of strain differentiation among isolates of Candida albicans obtained from hospitalized patients has been limited. We have applied biotyping and DNA restriction fragment analysis (DNA fingerprinting) by using EcoRI to the study of C. albicans isolates obtained from hospitalized patients. A total of 68 isolates from 15 patients were studied. Thirteen subtypes were identified by biotyping, 8 by DNA fingerprinting, and 21 by a combination of the biotyping and DNA fingerprinting approaches (composite subtype). Both techniques were highly reproducible. In examining the strain variation among isolates obtained from multiple anatomic sites over time, we found that similar, if not identical, strains were recovered from the oropharynx, urine, stool, and blood in a given patient, and these strains persisted. Only rarely did two patients share the same composite subtype suggesting sporadic nosocomial transmission. The combination of biotyping and DNA fingerprinting improved strain discrimination compared to either method alone. Further investigation with these and other epidemiologic typing methods will be necessary to enhance the understanding of the epidemiology and pathogenesis of candidiasis in hospitalized patients.

Bacterial Typing Techniques↗
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Prophylactic antibiotic therapy with cefamandole and tobramycin for patients undergoing renal transplantation.

The incidence of infections among patients undergoing renal transplantation has been reported as high as 83% during the first post-transplant year. In an effort to reduce the occurrence of such infections, we evaluated the role of perioperative prophylactic antibiotics in these patients. Thirty-seven patients undergoing transplantation were assigned randomly to treatment groups (N = 20, cefamandole, 1 gm IM every 6 hrs for 8 doses/tobramycin 1 mg/kg IM for 1 dose, starting 2 hrs prior to surgery) and control groups (N = 17, no antibiotics). A uniform infection surveillance system was used. Eighty-one percent (30/37) of patients became infected; 70% (14/20) of treated patients and 94% (16/17) of controls (p = 0.14). Since antibiotic prophylaxis might be expected to exert the greatest influence in the immediate postoperative period, we examined patient outcome data for both the first seven posttransplant days and for the entire hospitalization. Of the 38% (14/37) of patients who developed infections during the first posttransplant week, a statistically greater proportion came from the control group than from the treated group (10/17 vs. 4/20, p = 0.04). These data suggest that this regimen is effective in reducing the occurrence of infections during the first week following renal transplantation.

Adult↗
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Hospital-acquired infections in intensive care unit patients: an overview with emphasis on epidemics.

Surveillance activities for the detection of nosocomial infections at the University of Virginia Hospital (Charlottesville, Virginia) and at hospitals participating in the Virginia Statewide Infection Control Program have focused on outbreaks and device-related infections which are potentially preventable. Eleven outbreaks of nosocomial infections were identified at the University of Virginia Hospital between January 1, 1978 and December 31, 1982 (9.8 outbreaks/100,000 admissions). Ten of the 11 were centered in critical care units. The 269 patients involved in the epidemics represented 0.2% of all hospital admissions and 3.7% of all patients who developed nosocomial infections. Eight of the 11 outbreaks involved infection of the bloodstream, and the 90 patients who developed a bloodstream infection as part of an epidemic represented 8% of all patients with nosocomial bloodstream infections identified during the five-year study period. The reservoir of the 11 outbreaks involved devices (5), contaminated cocaine (1), probable blood products (1), other patients (3), and nursing personnel (1). Forty-one percent of all nosocomial bloodstream infections and 41% of all nosocomial pneumonias occurred in intensive care units (ICUs). In 38 hospitals in the state of Virginia with ICUs and practitioners who voluntarily reported surveillance data between June 1, 1980 and May 31, 1982, there were 264,757 patients admitted and a crude infection rate of 3%. Of note is that 1,867 of the 7,407 nosocomial infections (25%) occurred in the ICU patients. Several factors point to a compelling argument that the highest priority in infection control resources be assigned to the prevention and control of ICU infections: ICU patients often have serious device-related infections and may be identified as high risk prior to infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross Infection↗
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Pseudomonas cepacia: implications and control of epidemic nosocomial colonization.

In the 19-month period January 1979-July 1980, 56 patients became colonized or infected with Pseudomonas cepacia. Three groups of patients were identified. In group I, six otolaryngology patients became colonized when contaminated aqueous cocaine was used as a topical anesthetic. In group II, 24 patients became colonized from contaminated lidocaine normal-saline solutions that had been drawn into syringes in advance (setups) and used during bronchoscopy in the internal medicine department. In group III, the source of colonization of infection for 26 patients with sputum, wound, blood, or urine cultures positive for P. cepacia was not determined. However, contaminated aqueous cocaine, found in the pharmacy, had been given to several of these patients. Since most patients were colonized rather than infected with P. cepacia, there was an apparent disparity in the case count based on data obtained from microbiology records and data obtained from ongoing surveillance of nosocomial infections. Several patients who were merely colonized with P. cepacia were inappropriately treated with chloramphenicol. Successful control measures included sterilizing cocaine solutions in the otolaryngology department and in the pharmacy and eliminating contaminated set-ups in the internal medicine department.

Cross Infection↗
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Contaminated breast milk: A source of Klebsiella bacteremia in a newborn intensive care unit.

Five patients in a newborn intensive care unit (NICU) developed primary bacteremia due to Klebsiella during a 12-day period, May 2 through June 2, 1979, after feeding for 24-96 hr with contaminated breast milk. All patients had been fed via nasoduodenal tube with milk obtained from a single donor. The donor milk collected via electric suction pump was positive by gram stain for gram-negative rods and by culture for Klebsiella pneumoniae. A culture of hand-expressed milk was negative for gram-negative rods. The breast-pump tubing and safety trap were grossly contaminated with K. pneumoniae. Institution of proper sterilization to the pump equipment controlled the outbreak. This outbreak is the first documentation of nosocomial bacteremia as a major infectious complication of feedings of premature infants with contaminated breast milk.

Cross Infection↗
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Epidemiology of infections due to Pseudomonas aeruginosa.

Pseudomonas aeruginosa is responsible for an increasing proportion of infections acquired in the modern hospital setting. It accounts for 8.5% of all nosocomial infections and has an attack rate of 36 infections per 10,000 hospital discharges. P. aeruginosa represents the single most frequently isolated pathogen in patients with nosocomial pneumonia and burn-wound infections. The organism's bioepidemiology is linked to its ability to thrive in marginal econiches, and its ascendency as a nosocomial pathogen parallels the evolution of high-technology intensive care units, the large numbers of immunocompromised patients, and the liberal use of antibiotics. The reservoirs and modes of transmission for this organism are reviewed along with recent studies aimed at the prevention of both colonization and infection by this organism.

Cross Infection↗
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The outlook for prevention and treatment of infections due to Pseudomonas aeruginosa.

Control measures based on careful hospital surveillance are aimed primarily at minimizing environmental sources of Pseudomonas aeruginosa. Other important aspects of epidemiologic control include aggressive evaluation of outbreaks and limitation of antimicrobial use. Potent new antimicrobial chemotherapy has been developed, with most new agents of the beta-lactam and aminoglycoside classes. In spite of these developments, the likelihood of drug resistance seems great and the search for novel compounds continues. Of greatest appeal are approaches that augment host defences. Replacement or supplementation of circulating phagocytic cells is conceptually attractive, but this approach has encountered major technical problems and complications. More recently, there has been important progress in developing immunologic approaches aimed at augmenting circulating antibodies. Development of monoclonal antibodies and new methods for preparing hyperimmune globulins has produced forms of intervention that must be tested by clinical trials, but not all patients may benefit from augmentation of circulating antibodies to P. aeruginosa.

Anti-Bacterial Agents↗
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Contaminated enteral nutrition solutions as a cause of nosocomial bloodstream infection: a study using plasmid fingerprinting.

In July 1984, two patients fed enteral nutrition solutions contaminated with Enterobacter cloacae developed nosocomial bacteremia. Despite careful review of the preparation procedures as well as repeated microbiological surveys, 83 (27%) of the 309 formula bottles tested over a 1-yr period were contaminated and the source of contamination remained unknown. E. cloacae was the most frequent organism isolated (34%). The plasmid profiles of E. cloacae recovered from enteral nutrition solutions remained identical for several months. Blood culture isolates from 10 of the 40 patients who had developed E. cloacae nosocomial sepsis over a 7-yr period (1979-1985) had plasmid profiles linking them to contaminated enteral nutrition solutions. Epidemiological data from a case control study revealed that these 10 patients were indeed more likely to be exposed to enteral nutrition than the 30 others: 9/10 vs 10/30 (odds ratio 18, p = 0.002). Similarly, two of seven nosocomial Klebsiella pneumoniae bacteremias over a 6-month period in 1986 could be ascribed to administration of contaminated enteral liquid feeds prompting a general policy for using sterile commercially prepared solutions. Our results suggest that contaminated enteral nutrition solutions represent a significant cause of nosocomial sepsis.

Adult↗
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The impact of hospital-acquired bloodstream infections.

Nosocomial bloodstream infections are a leading cause of death in the United States. If we assume a nosocomial infection rate of 5%, of which 10% are bloodstream infections, and an attributable mortality rate of 15%, bloodstream infections would represent the eighth leading cause of death in the United States. Because most risk factors for dying after bacteremia or fungemia may not be changeable, prevention efforts must focus on new infection-control technology and techniques.

Cross Infection↗
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Epidemiology of bone fractures occurring during hospitalization.

OBJECTIVE: To investigate the incidence and epidemiology of nosocomial bone fractures. DESIGN: Observational, case series. SETTING: Tertiary care center. PATIENTS: All patients sustaining a fracture during hospitalization during the 18-month study period from July 1989 through December 1990. RESULTS: Twenty nosocomial fractures were identified. Twelve of these resulted from falls (3.5 fractures from falls/100,000 patient days). Fracture rates were higher on the neurology service than on other services. Patients who fell and sustained a fracture were significantly older than patients who fell but did not sustain a fracture (74 versus 58 years, respectively, p < .05). Falls occurring on weekends and holidays were approximately three times more likely to result in fracture than falls occurring on other days (p = .06). CONCLUSIONS: Nosocomial fractures were infrequent events but were more common in the elderly and in persons with significant neuropsychological impairment. Persons who sustained fractures during hospitalization were similar to those who fell and fractured bones in a community setting.

Accidental Falls↗
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Predicting survival of patients with sepsis by use of regression and neural network models.

OBJECTIVES: (1) To predict at the time of diagnosis of sepsis the subsequent occurrence of multiple organ failure and patient death; and (2) to compare the prediction accuracies of standard multiple logistic regression (MLR) and neural network (NN) models. METHODS: The data were collected during a 5-year period for all patients (n=173) who met prospectively determined criteria for sepsis and had positive blood culture results while admitted in the surgical intensive care unit at the University Hospital of Geneva, Switzerland. These data formed the basis for a retrospective cohort study described elsewhere. The MLR model was adapted from existing data. An NN model of the feed-forward, back-propagation type was constructed for predicting the outcome of sepsis with bloodstream infection. Both models were constructed from randomly chosen subsets of patients and subsequently were evaluated on the remaining (independent) patients. RESULTS: Survival after sepsis was predicted with an accuracy of 80% by the NN model, which used only information collected at the time of the diagnosis of sepsis. The development of multiple organ failure after the diagnosis of sepsis was predicted accurately (81.5%) with either the MLR or the NN model. Both the MLR and the NN methods depended on the interpretation of a likelihood quantity, requiring the choice of a threshold to make a survival prediction. The accuracy of the MLR models was very sensitive to the threshold value. The accuracy of the NN models was not sensitive to the choice of threshold, because they generated likelihood predictions that were distributed far from the middle range where the threshold was placed. CONCLUSION: Compared with MLR models, the NN models were slightly more accurate and much less sensitive to the arbitrary threshold parameter.

Bacterial Infections↗
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Staphylococcus aureus bacteremia: the cost-effectiveness of long-term therapy associated with infectious diseases consultation.

OBJECTIVE: To investigate the cost-effectiveness of long-term therapy for Staphylococcus aureus bacteremia and to determine if an infectious diseases consultation affected the duration of therapy. METHODS: A decision analysis was performed based on data from the literature. To determine if consultation was related to therapy duration, a retrospective cohort study was performed using tightly matched pairs. RESULTS: The excess cost per life saved by long-term antibiotics was $500,000. The excess cost per life-year saved was $18,000. Nine pairs were matched. Patients who received consultation were more likely to receive long-term therapy than controls (median 41 days vs 15 days for controls, P = .04). CONCLUSIONS: The estimated cost per life-year saved by long-term therapy was similar to other accepted medical interventions. Infectious diseases consultation can encourage prolonged duration of antibiotic therapy for S aureus bacteremia.

Anti-Bacterial Agents↗
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Costs of providing primary care: comparison of an academic general medicine practice with an MGMA benchmark.

Market-based healthcare reform has placed great financial pressures on academic departments of internal medicine. The current emphasis and increased recruiting for primary care have not been accompanied by a financially supportive institutional culture or favorable third-party reimbursement system for the generalist practitioners. In one department's analysis, there was a large difference in revenue (-$130,000) compared to a Medical Group Management Association (MGMA) standard, yet a reduced level of compensation for primary-care physicians, $61,000 less per full-time equivalent (FTE). Total overhead per FTE in our department was $80,000 greater than comparable practices of the MGMA standard. We have estimated the institutional strategic costs of having primary-care clinics in three separate locations in the city of Richmond ($74,000/FTE). No viable cost-cutting options placed the primary-care program in positive balance, but the analysis contributed to a creative institutional approach for a solution.

Academic Medical Centers↗