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Biomedical subjects

R P Wenzel

Publications and source records attributed to R P Wenzel.

At least 91 records · Page 5Linked to original sources
PubMed1995

Nosocomial bloodstream infections. Secular trends in rates, mortality, and contribution to total hospital deaths.

BACKGROUND: Nosocomial bloodstream infections occur at a rate of 1.3 to 14.5 per 1000 hospital admissions and are believed to lead directly to 62,500 deaths per year in the United States. Measures of the incidence and the proportion of all hospital deaths related to deaths from these infections provide estimates of their impact. The objectives of the study were to characterize the secular trends in nosocomial bloodstream infection at a single institution and to estimate the population-attributable risk for death among patients experiencing the infection. METHODS: A 12-year retrospective study using prospectively collected data from a hospital-wide surveillance system for nosocomial infections in a 900-bed tertiary care institution. All patients (N = 260,834) admitted to the institution between 1980 and 1992 were included in the study. Bloodstream infection rates were calculated for the 10 leading groups of pathogens, and trends were analyzed using simple linear regression. In-hospital mortality rates from patients who did or did not develop nosocomial blood stream infections were compared. RESULTS: Between 1980 and 1992, a total of 3077 patients developed 3464 episodes of nosocomial bloodstream infection. The crude infection rates increased linearly from 6.7 to 18.4 per 1000 discharges (0.83 to 1.72 episodes per 1000 patient-days) during the 12-year study period (r = .87). Increases in the infection rates were due to gram-positive cocci (r = .96) and yeasts (r = .95) and essentially explained by infections caused by coagulase-negative staphylococci, Staphylococcus aureus, enterococci, and Candida species, respectively. Although the crude mortality in patients with nosocomial bloodstream infections decreased from 51% in 1981 to 29% in 1992, the in-hospital population-attributable mortality among infected patients increased from 3.55 deaths per 1000 discharges in 1981 to 6.22 per 1000 discharges in 1992 (r = .67). The etiologic fraction or the proportion of deaths in patients with bloodstream infection to all deaths occurring in the hospital increased from 11.4% in 1981 to 20.4% in 1992 (r = .59). CONCLUSIONS: The incidence, the etiologic fraction, and the population-attributable risk for death among patients experiencing nosocomial bloodstream infections increased progressively during the last decade.

Bacteremia↗
PubMed1995

The natural history of the systemic inflammatory response syndrome (SIRS). A prospective study.

OBJECTIVE: Define the epidemiology of the four recently classified syndromes describing the biologic response to infection: systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, and septic shock. DESIGN: Prospective cohort study with a follow-up of 28 days or until discharge if earlier. SETTING: Three intensive care units and three general wards in a tertiary health care institution. METHODS: Patients were included if they met at least two of the criteria for SIRS: fever or hypothermia, tachycardia, tachypnea, or abnormal white blood cell count. MAIN OUTCOMES MEASURES: Development of any stage of the biologic response to infection: sepsis, severe sepsis, septic shock, end-organ dysfunction, and death. RESULTS: During the study period 3708 patients were admitted to the survey units, and 2527 (68%) met the criteria for SIRS. The incidence density rates for SIRS in the surgical, medical, and cardiovascular intensive care units were 857, 804, and 542 episodes per 1000 patient-days, respectively, and 671, 495, and 320 per 1000 patient-days for the medical, cardiothoracic, and general surgery wards, respectively. Among patients with SIRS, 649 (26%) developed sepsis, 467 (18%) developed severe sepsis, and 110 (4%) developed septic shock. The median interval from SIRS to sepsis was inversely correlated with the number of SIRS criteria (two, three, or all four) that the patients met. As the population of patients progressed from SIRS to septic shock, increasing proportions had adult respiratory distress syndrome, disseminated intravascular coagulation, acute renal failure, and shock. Positive blood cultures were found in 17% of patients with sepsis, in 25% with severe sepsis, and in 69% with septic shock. There were also stepwise increases in mortality rates in the hierarchy from SIRS, sepsis, severe sepsis, and septic shock: 7%, 16%, 20%, and 46%, respectively. Of interest, we also observed equal numbers of patients who appeared to have sepsis, severe sepsis, and septic shock but who had negative cultures. They had been prescribed empirical antibiotics for a median of 3 days. The cause of the systemic inflammatory response in these culture-negative populations is unknown, but they had similar morbidity and mortality rates as the respective culture-positive populations. CONCLUSIONS: This prospective epidemiologic study of SIRS and related conditions provides, to our knowledge, the first evidence of a clinical progression from SIRS to sepsis to severe sepsis and septic shock.

Diagnosis-Related Groups↗
PubMed1995

Systemic inflammatory response syndrome, sepsis, severe sepsis and septic shock: incidence, morbidities and outcomes in surgical ICU patients.

OBJECTIVES: To determine the incidence of systemic inflammatory response syndrome (SIRS), sepsis and severe sepsis in surgical ICU patients and define patient characteristics associated with their acquisition and outcome. DESIGN: One-month prospective study of critically ill patients with a 28 day in-hospital follow up. SETTING: Surgical intensive care unit (SICU) at a tertiary care institution. METHODS: All patients (n = 170) admitted to the SICU between April 1 and April 30, 1992 were prospectively followed for 28 days. Daily surveillance was performed by two dedicated, specifically-trained research nurses. Medical and nursing chart reviews were performed, and follow up information at six and twelve months was obtained. RESULTS: The in-hospital surveillance represented 2246 patient-days, including 658 ICU patient-days. Overall, 158 patients (93%) had SIRS for an incidence of 542 episodes/1000 patients-days. The incidence of SIRS in the ICU was even higher (840 episodes/1000 patients-days). A total of 83 patients (49%) had sepsis; among them 28 developed severe sepsis. Importantly, 13 patients had severe sepsis after discharge from the ICU. Patient groups were comparable with respect to age, sex ratio, and type of surgery performed. Apache II score on admission to the ICU and ASA score at time of surgery were significantly higher (p < 0.05) only for patients who subsequently developed severe sepsis. The crude mortality at 28 days was 8.2% (14/170); it markedly differed among patient groups: 6% for those with SIRS vs. 35% for patients with severe sepsis. Patients with sepsis and severe sepsis had a longer mean length of ICU stay (2.1 +/- 0.2 and 7.5 +/- 1.5, respectively) than those with SIRS (1.45 +/- 0.1) or control patients (1.16 +/- 0.1). Total length of hospital stay also markedly differed among groups (35 +/- 9 (severe sepsis), 24 +/- 2 (sepsis), 11 +/- 0.8 (SIRS), and 9 +/- 0.1 (controls, respectively). CONCLUSIONS: Almost everyone in the SICU had SIRS. Therefore, because of its poor specificity, SIRS was not helpful predicting severe sepsis and septic shock. Patients who developed sepsis or severe sepsis had higher crude mortality and length of stay than those who did not. Studies designed to identify those who develop complications of SIRS would be very useful.

Critical Care↗
PubMed1995

The significance of nasal carriage of Staphylococcus aureus and the incidence of postoperative wound infection.

Staphylococcus aureus infections are associated with considerable morbidity and, in certain situations, mortality. The association between the nasal carriage of S. aureus and subsequent infection has been comprehensively established in a variety of clinical settings, in particular, patients undergoing haemodialysis and continuous ambulatory peritoneal dialysis (CAPD), and in patients undergoing surgery. Postoperative wound infections are associated with a high degree of morbidity and represent an important medical issue. Until recently, eradication of S. aureus nasal carriage by various topical and systemic agents had proved unsuccessful. Mupirocin is a novel topical antibiotic with excellent antibacterial activity against staphylococci. Recent studies have demonstrated that intranasal administration of mupirocin is effective in eradicating the nasal carriage of S. aureus and in reducing the incidence of S. aureus infections in haemodialysis and CAPD patients. It has been suggested that sufficient evidence now exists to test the hypothesis that eradication of the carrier state in surgical patients preoperatively may reduce the incidence of S. aureus postoperative wound infections.

Administration, Intranasal↗
PubMed1995

The Lowbury Lecture. The economics of nosocomial infections.

A simple model of the costs and benefits of an infection control programme is presented. Liberal costs and conservative benefits were assumed. The concepts of crude and attributable mortality were applied to examine the cost per life year saved if a minority of infection-related deaths were prevented. An effective infection control programme is one of the most cost-beneficial medical interventions available in modern public health.

Cost Savings↗
PubMed1995

Evidence of nosocomial spread of Candida albicans causing bloodstream infection in a neonatal intensive care unit.

Candida albicans is an increasingly important bloodstream pathogen. We investigated a cluster of bloodstream infections in the neonatal intensive care unit (NICU) to determine whether nosocomial transmission occurred. Subjects included any patient in the NICU who developed clinically significant bloodstream infection with C. albicans from January 1984 to December 1987 (N = 7). Isolates were typed by restriction fragment length polymorphism analysis using a C. albicans-specific DNA probe (27A). Four of the neonates were infected from June to August 1984 (1.4 infections per 100 admissions) (the epidemic period) versus none in the period from January to May 1984, and three in the period from September 1984 to December 1987 (0.12 infections per 100 admissions) (P = .002). Three of the four patients in the epidemic period were infected with identical strains, readily distinguished from epidemiologically unrelated strains from the NICU. We conclude that nosocomial transmission of C. albicans occurred and that neonates in intensive care units may represent one group at increased risk.

Blotting, Southern↗
PubMed1995

The hospital epidemiologist: practical ideas.

The modern hospital epidemiologist has broad perspectives and influence across clinical departmental lines. The opportunities to improve patient care by expanding traditional areas of focus beyond infection control are great. Useful skills include epidemiology, communication, and respect for colleagues.

Epidemiology↗
PubMed1995

Vancomycin-resistant Enterococcus faecium bacteremia: risk factors for infection.

We describe an outbreak of vancomycin-resistant Enterococcus faecium (vanA phenotype) bacteremia on the oncology ward of a tertiary care community hospital. In 10 of the 11 cases the patients had leukemia and were neutropenic (median duration of neutropenia, 21 days) at the time of bacteremia. On average, patients received six antibiotic agents for a total of 61 agent-days prior to development of vancomycin-resistant E. faecium bacteremia. The mortality rate was 73%. Molecular typing of 22 isolates revealed that the majority (83%) represented a common strain, indicating nosocomial spread. When the 11 cases were compared to 22 matched control patients, gastrointestinal colonization with vancomycin-resistant E. faecium (odds ratio [denominator, 0] infinity, P = .005) and the use of antimicrobial agents with significant activity against anaerobes (metronidazole, clindamycin, and imipenem; odds ratio infinity, P = .02) were found to be risk factors for the development of vancomycin-resistant E. faecium bacteremia. Since no proven therapy for such infection exists, there is an urgent need to identify effective measures to prevent and control the development of vancomycin-resistant E. faecium bacteremia.

Adult↗
PubMed1995

Nosocomial candidemia: risk factors and attributable mortality.

Over the past decade, the incidence of hospital-acquired bloodstream infections caused by Candida species has risen and the species associated with such infections have changed. The incidence of candidemia is dramatically higher in high-risk, critical-care units than in other parts of the hospital. Certain underlying physical conditions including acute leukemia, leukopenia, burns, gastrointestinal disease, and premature birth predispose patients to nosocomial candidemia. Independent risk factors include prior treatment with multiple antibiotics, prior Hickman catheterization, isolation of Candida species from sites other than the blood, and prior hemodialysis. In this article some of the challenges posed by the management of nosocomial candidemia are presented in three case studies. In addition, the results of several investigations of nosocomial candidemia at the University of Iowa Hospitals and Clinics are reviewed.

Adult↗
PubMed1995

Familial carriage of methicillin-resistant Staphylococcus aureus and subsequent infection in a premature neonate.

During routine surveillance of patients in a Neonatal Intensive Care Unit (NICU), an alert infection-control practitioner confirmed the relationship of the index patient (sibling 3) who had a methicillin-resistant Staphylococcus aureus (MRSA) infection to an infant sibling (sibling 2) who had been admitted to the hospital 7 months previously with an MRSA infection. Cultures of nasal specimens obtained from the index patient's parents and two other siblings also yielded MRSA for two of the family members, the mother and sibling 1. The strains were typed by antibiogram, plasmid analysis, and genomic DNA typing. The isolates from sibling 1, sibling 2, the mother, and one isolate from sibling 3 were found to be identical by all techniques. The other isolates from sibling 3 shared the same genomic type but had no detectable plasmids. These findings suggest that transmission of this strain occurred at least three times within this family and that at least one family member was colonized with the same strain for 7 months or more. Recognition that family members may serve as reservoirs for nosocomial infections with MRSA raises important issues for infection control.

Adult↗
PubMed1995

A second large controlled clinical study of E5, a monoclonal antibody to endotoxin: results of a prospective, multicenter, randomized, controlled trial. The E5 Sepsis Study Group.

OBJECTIVE: To evaluate the safety and efficacy of E5, a murine, monoclonal antibody directed against endotoxin, in the treatment of patients with Gram-negative sepsis. DESIGN: A multicenter, randomized, double-blind, placebo-controlled trial. SETTING: Fifty-three hospitals across the United States, including university medical centers, Veterans Affairs Medical Centers, and community hospitals. PATIENTS: 847 patients were randomized into this study. Enrolled patients met criteria for three conditions: a) known or suspected Gram-negative infection; b) clinical evidence of sepsis; and c) signs of end-organ dysfunction. Patients with refractory shock were excluded from the study. INTERVENTIONS: Two doses of E5 (2 mg/kg/day by intravenous infusion 24 hrs apart), or placebo that was identical in appearance were administered. In addition, all patients received standard supportive therapy and broad-spectrum antibiotics. MEASUREMENTS AND MAIN RESULTS: The primary end point was mortality over 30 days. Secondary outcome measures included the resolution and prevention of organ failure in the same two populations. Additionally, the safety of E5 was evaluated. There was no significant improvement in survival over 30 days among patients with Gram-negative sepsis who received E5 compared with those patients who received placebo (n = 530; p = .21). In addition, E5 did not improve survival for patients with Gram-negative sepsis and organ failure (n = 139; p = .3). However, a significantly greater percentage of patients with Gram-negative sepsis experienced resolution of major organ failure if they received E5, compared with those patients who received placebo (n = 139; 48% E5 vs. 25% placebo; p = .005). This result extended to all patients who entered the study with one or more major organ failures, regardless of the etiology of the infection (n = 225; 41% E5 vs. 27% placebo; p = .024). E5 also provided protection against the development of some organ failures, but significant prevention was only observed for adult respiratory distress syndrome (p = .007) and central nervous system dysfunction (p = .050). Hypersensitivity reactions attributable to E5 occurred in 2.6% of patients. An asymptomatic antibody response occurred in 44% of the E5-treated patients and in 12% of the patients who received placebo. CONCLUSIONS: In this study, E5 did not reduce mortality in nonshock patients with Gram-negative sepsis whether or not those patients also had organ failure. However, E5 did result in greater resolution of organ failure in patients with Gram-negative sepsis. This benefit extended to those patients with suspected Gram-negative etiology. This finding is important because patients with suspected Gram-negative sepsis and organ failure can be identified without waiting for culture results. In addition, E5 resulted in the prevention of adult respiratory distress syndrome and central nervous system organ failure. However, more studies are needed to determine if this result can be extended to organ failure in general. E5 is safe as a treatment for patients with Gram-negative sepsis.

Antibodies, Monoclonal↗
PubMed1995

Molecular epidemiology of an outbreak of meningococcal disease in a university community.

Over a 2-month period, five cases of serogroup C meningococcal disease occurred in Iowa City, Iowa. Two patients were unacquainted university students who had independently visited another university with endemic meningococcal disease. Isolates from these patients had DNA fingerprints identical to those of the isolates responsible for infections on the other campus. Three cases for which the patients' isolates had a different DNA fingerprint were linked to visiting a local tavern. To disrupt the outbreak, the University of Iowa offered free meningococcal vaccine to all students. This report demonstrates that outbreaks of meningococcal disease may be due to more than one circulating strain and illustrates the utility of pulsed-field gel electrophoresis in defining the molecular epidemiology of meningococcal infections.

Adolescent↗
PubMed1994

Long-term efficacy of intranasal mupirocin ointment. A prospective cohort study of Staphylococcus aureus carriage.

BACKGROUND: We investigated the long-term effect of a single 5-day application of intranasal mupirocin calcium ointment on Staphylococcus aureus nasal and hand colonization. The subjects were 68 healthy volunteers who were health care workers with stable S aureus nasal carriage and who had participated in a randomized, double-blind placebo-controlled clinical trial of intranasal mupirocin ointment. METHODS: A 1-year prospective cohort study of S aureus nasal carriers after treatment with active drug or placebo was performed. Cultures were obtained from all subjects 6 and 12 months after therapy. All subjects returned for the 6-month visit; 63 (93%) were examined at 1 year. The major outcome measure was the relative proportion of any S aureus cultured at either site at 6 and 12 months. The S aureus isolates were typed by restriction endonuclease analysis of plasmid DNA and by antibiotic susceptibility tests; the similarity of nasal and hand isolate "fingerprints" was compared. RESULTS: At 6 months, nasal carriage was 48% in the treatment group vs 72% in controls (relative risk, 0.68; 95% confidence interval, 0.45 to 1.02; P = .054); at 1 year, nasal carriage was 53% vs 76%, respectively (relative risk, 0.70; 95% confidence interval, 0.48 to 1.02; P = .056). Hand carriage at 6 months was significantly reduced among mupirocin recipients relative to controls (15% and 48%; P = .04, adjusted for the baseline rate of hand carriage). Thirty-six percent of treated subjects were recolonized in the nares with a new strain at 1 year, whereas 34% had reisolation of the original strain after initially negative posttherapy cultures. During the year of follow-up, hand carriage was observed at least once in two thirds of the subjects. Nearly all of the hand isolates (87%) exactly matched the subjects' coincident nasal plasmid fingerprint and antibiogram type. CONCLUSIONS: A single brief treatment course of intranasal mupirocin was effective in reducing nasal S aureus carriage for up to 1 year. When S aureus was recovered after nasal decolonization, the new isolate was as likely to represent colonization with a new strain as reisolation of the original strain. Staphylococcus aureus hand carriage was significantly decreased 6 months after therapy, further implicating the nares as the primary reservoir site for hand carriage.

Administration, Intranasal↗
PubMed1994

Nosocomial bloodstream infection in critically ill patients. Excess length of stay, extra costs, and attributable mortality.

OBJECTIVE: To determine the excess length of stay, extra costs, and mortality attributable to nosocomial bloodstream infection in critically ill patients. DESIGN: Pairwise-matched (1:1) case-control study. SETTING: Surgical intensive care unit (SICU) in a tertiary health care institution. PATIENTS: All patients admitted in the SICU between July 1, 1988, and June 30, 1990, were eligible. Cases were defined as patients with nosocomial bloodstream infection; controls were selected according to matching variables in a stepwise fashion. METHODS: Matching variables were primary diagnosis for admission, age, sex, length of stay before the day of infection in cases, and total number of discharge diagnoses. Matching was successful for 89% of the cohort; 86 matched case-control pairs were studied. MAIN OUTCOME MEASURES: Crude and attributable mortality, excess length of hospital and SICU stay, and overall costs. RESULTS: Nosocomial bloodstream infection complicated 2.67 per 100 admissions to the SICU during the study period. The crude mortality rates from cases and controls were 50% and 15%, respectively (P < .01); thus, the estimated attributable mortality rate was 35% (95% confidence interval, 25% to 45%). The median length of hospital stay significantly differed between cases and controls (40 vs 26 days, respectively; P < .01). When only matched pairs who survived bloodstream infection were considered (n = 41), cases stayed in the hospital a median of 54 days vs 30 days for controls (P < .01), and cases stayed in the SICU a median of 15 days vs 7 days for controls (P < .01). Thus, extra hospital and SICU length of stay attributable to bloodstream infection was 24 and 8 days, respectively. Extra costs attributable to the infection averaged $40,000 per survivor. CONCLUSIONS: The attributable mortality from nosocomial bloodstream infection is high in critically ill patients. The infection is associated with a doubling of the SICU stay, an excess length of hospital stay of 24 days in survivors, and a significant economic burden.

Case-Control Studies↗