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Biomedical subjects

Richard P Wenzel

Publications and source records attributed to Richard P Wenzel.

At least 19 recordsLinked to original sources

A prospective study of outcomes, healthcare resource utilization, and costs associated with postoperative nosocomial infections.

OBJECTIVE: We evaluated 4 important outcomes associated with postoperative nosocomial infection: costs, mortality, excess length of stay, and utilization of healthcare resources. DESIGN: The outcomes for patients who underwent general, cardiothoracic, and neurosurgical operations were recorded during a previous clinical trial. Multivariable analyses including significant covariates were conducted to determine whether nosocomial infection significantly affected the outcomes. SETTING: A large tertiary care medical center and an affiliated Veterans Affairs Medical Center. PATIENTS: A total of 3,864 surgical patients. RESULTS: The overall nosocomial infection rate was 11.3%. Important covariates included age, Karnofsky score, McCabe and Jackson classification of the severity of underlying disease, National Nosocomial Infection Surveillance system risk index, and number of comorbidities. After accounting for covariates, nosocomial infection was associated with increased postoperative length of stay, increased costs, increased hospital readmission rate, and increased use of antimicrobial agents in the outpatient setting. Nosocomial infection was not associated independently with a significantly increased risk of death in this surgical population. CONCLUSION: Postoperative nosocomial infection was associated with increased costs of care and with increased utilization of medical resources. To accurately assess the effects of nosocomial infections, one must take into account important covariates. Surgeons seeking to decrease the cost of care and resource utilization must identify ways to decrease the rate of postoperative nosocomial infection.

Adult↗

Systemic inflammatory response syndrome in adult patients with nosocomial bloodstream infections due to enterococci.

BACKGROUND: Enterococci are the third leading cause of nosocomial bloodstream infection (BSI). Vancomycin resistant enterococci are common and provide treatment challenges; however questions remain about VRE's pathogenicity and its direct clinical impact. This study analyzed the inflammatory response of Enterococcal BSI, contrasting infections from vancomycin-resistant and vancomycin-susceptible isolates. METHODS: We performed a historical cohort study on 50 adults with enterococcal BSI to evaluate the associated systemic inflammatory response syndrome (SIRS) and mortality. We examined SIRS scores 2 days prior through 14 days after the first positive blood culture. Vancomycin resistant (n = 17) and susceptible infections (n = 33) were compared. Variables significant in univariate analysis were entered into a logistic regression model to determine the affect on mortality. RESULTS: 60% of BSI were caused by E. faecalis and 34% by E. faecium. 34% of the isolates were vancomycin resistant. Mean APACHE II (A2) score on the day of BSI was 16. Appropriate antimicrobials were begun within 24 hours in 52%. Septic shock occurred in 62% and severe sepsis in an additional 18%. Incidence of organ failure was as follows: respiratory 42%, renal 48%, hematologic 44%, hepatic 26%. Crude mortality was 48%. Progression to septic shock was associated with death (OR 14.9, p < .001). There was no difference in A2 scores on days -2, -1 and 0 between the VRE and VSE groups. Maximal SIR (severe sepsis, septic shock or death) was seen on day 2 for VSE BSI vs. day 8 for VRE. No significant difference was noted in the incidence of organ failure, 7-day or overall mortality between the two groups. Univariate analysis revealed that AP2>18 at BSI onset, and respiratory, cardiovascular, renal, hematologic and hepatic failure were associated with death, but time to appropriate therapy >24 hours, age, and infection due to VRE were not. Multivariate analysis revealed that hematologic (OR 8.4, p = .025) and cardiovascular failure (OR 7.5, p = 032) independently predicted death. CONCLUSION: In patients with enterococcal BSI, (1) the incidence of septic shock and organ failure is high, (2) patients with VRE BSI are not more acutely ill prior to infection than those with VSE BSI, and (3) the development of hematologic or cardiovascular failure independently predicts death.

Adult↗

Comparison of severity of illness scoring systems for patients with nosocomial bloodstream infection due to Pseudomonas aeruginosa.

BACKGROUND: Several acute illness severity scores have been proposed for evaluating patients on admission to intensive care units but these have not been compared for patients with nosocomial bloodstream infection (nBSI). We compared three severity of illness scoring systems for predicting mortality in patients with nBSI due to Pseudomonas aeruginosa. METHODS: We performed a historical cohort study on 63 adults in intensive care units with P. aeruginosa monomicrobial nBSI. RESULTS: The Acute Physiology, Age, Chronic Health Evaluation II (APACHE II), Sequential Organ Failure Assessment (SOFA), and Simplified Acute Physiologic Score (SAPS II), were calculated daily from 2 days prior through 2 days after the first positive blood culture. Calculation of the area under the receiver operating characteristic (ROC) curve confirmed that APACHE II and SAPS II at day -1 and SOFA at day +1 were better predictors of outcome than days -2, 0 and day 2 of BSI. By stepwise logistic regression analysis of these three scoring systems, SAPS II (OR: 13.03, CI95% 2.51-70.49) and APACHE II (OR: 12.51, CI95% 3.12-50.09) on day -1 were the best predictors for mortality. CONCLUSION: SAPS II and APACHE II are more accurate than the SOFA score for predicting mortality in this group of patients at day -1 of BSI.

APACHE↗

Infection control and the prevention of nosocomial infections in the intensive care unit.

Nosocomial infections continue to be significant causes of morbidity, mortality, and added costs in the health care setting. Half of all life-threatening nosocomial bloodstream infections and pneumonias occur in intensive care units (ICUs), despite ICUs representing only 15 to 20% of all hospital beds. Thus an efficient focus for prevention and control of life-threatening health care-associated infections should be in ICUs. Further, growing antibiotic resistance complicates the therapy of serious infections. Meticulous infection control practice with continued attention to hand hygiene is of paramount importance. Strict adherence to evidence-based catheter insertion and maintenance policies reduces nosocomial bloodstream infections. Evidence-based prevention strategies for ventilator-associated pneumonia, including management of respiratory equipment according to published guidelines and maintaining backrest elevation at 30 to 45 degrees, are effective. For greatest risk reduction, multifaceted programs ensuring maximal adherence with evidence-based infection control guidelines are needed.

Cross Infection↗

Systemic inflammatory response syndrome in nosocomial bloodstream infections with Pseudomonas aeruginosa and Enterococcus Species: comparison of elderly and nonelderly patients.

OBJECTIVES: To determine whether the systemic inflammatory response syndrome (SIRS), clinical course, and outcome of monomicrobial nosocomial bloodstream infection (BSI) due to Pseudomonas aeruginosa or Enterococcus spp. is different in elderly patients than in younger patients. DESIGN: Historical cohort study. SETTING: An 820-bed tertiary care facility. PARTICIPANTS: One hundred twenty-seven adults with P. aeruginosa or enterococcal BSI. MEASUREMENTS: SIRS scores were determined 2 days before the first positive blood culture through 14 days afterwards. Elderly patients (> or =65, n=37) were compared with nonelderly patients (<65, n=90). Variables significant for predicting mortality in univariate analysis were entered into a logistic regression model. RESULTS: No difference in SIRS was detected between the two groups. No significant difference was noted in the incidence of organ failure, 7-day mortality, or overall mortality between the two groups. Univariate analysis revealed that Acute Physiology And Chronic Health Evaluation (APACHE) II score of 15 or greater at BSI onset; adjusted APACHE II score (points for age excluded) of 15 or greater at BSI onset; and respiratory, cardiovascular, renal, hematological, and hepatic failure were predictors of mortality. Age, sex, use of empirical antimicrobial therapy, and infection with imipenem-resistant P. aeruginosa or vancomycin-resistant enterococci did not predict mortality. Multivariate analysis revealed that hematological failure (odds ratio (OR)=8.1, 95% confidence interval (CI)=2.78-23.47), cardiovascular failure (OR=4.7, 95% CI=1.69-13.10), and adjusted APACHE II > or = 15 at BSI onset (OR=3.1, 95% CI=1.12-8.81) independently predicted death. CONCLUSION: Elderly patients did not differ from nonelderly patients with respect to severity of illness before or at the time of BSI. Elderly patients with pseudomonal or enterococcal BSIs did not have a greater mortality than nonelderly patients.

Age Factors↗

Time to blood culture positivity as a predictor of clinical outcome of Staphylococcus aureus bloodstream infection.

Few studies have assessed the time to blood culture positivity as a predictor of clinical outcome in bloodstream infections (BSIs). The purpose of this study was to evaluate the time to positivity (TTP) of blood cultures in patients with Staphylococcus aureus BSIs and to assess its impact on clinical outcome. We performed a historical cohort study with 91 adult patients with S. aureus BSIs. TTP was defined as the time between the start of incubation and the time that the automated alert signal indicating growth in the culture bottle sounded. Patients with BSIs and TTPs of culture of </=12 h (n = 44) and >12 h (n = 47) were compared. Septic shock occurred in 13.6% of patients with TTPs of </=12 h and in 8.5% of patients with TTP of >12 h (P = 0.51). A central venous catheter source was more common with a BSI TTP of </=12 h (P = 0.010). Univariate analysis revealed that a Charlson score of >/=3, the failure of at least one organ (respiratory, cardiovascular, renal, hematologic, or hepatic), infection with methicillin-resistant S. aureus, and TTPs of </=12 h were associated with death. Age, gender, an APACHE II score of >/=20 at BSI onset, inadequate empirical antibiotic therapy, hospital-acquired bacteremia, and endocarditis were not associated with mortality. Multivariate analysis revealed that independent predictors of hospital mortality were a Charlson score of >/=3 (odds ratio [OR], 14.4; 95% confidence interval [CI], 2.24 to 92.55), infection with methicillin-resistant S. aureus (OR, 9.3; 95% CI, 1.45 to 59.23), and TTPs of </=12 h (OR, 6.9; 95% CI, 1.07 to 44.66). In this historical cohort study of BSIs due to S. aureus, a TTP of </=12 h was a predictor of the clinical outcome.

Adult↗

Ramoplanin: a topical lipoglycodepsipeptide antibacterial agent.

Ramoplanin, a novel antibiotic with activity against aerobic and anaerobic gram-positive bacteria, acts to prevent cell wall peptidoglycan formation by binding to a key intermediate moiety, lipid II. It has been fast-tracked by the US FDA for the prevention of enterococcal infections and the treatment of Clostridium difficile. The minimum inhibitory concentration(90s) have been < or = 1.0 microg/ml against gram-positive organisms examined. In carriers of vancomycin-resistant enterococci, a double-blind, placebo-controlled Phase II trial of two doses of ramoplanin versus placebo showed proof of concept. A second Phase II trial also demonstrated the equivalence of ramoplanin compared with vancomycin for the treatment of C. difficile colitis. The clinical value and place in therapy of ramoplanin is dependent upon the results of Phase III trials addressing its utility in suppressing carriage of target organisms in the gastrointestinal tract or in the nares.

Administration, Topical↗

Comparison of the systemic inflammatory response syndrome between monomicrobial and polymicrobial Pseudomonas aeruginosa nosocomial bloodstream infections.

BACKGROUND: Some studies of nosocomial bloodstream infection (nBSI) have demonstrated a higher mortality for polymicrobial bacteremia when compared to monomicrobial nBSI. The purpose of this study was to compare differences in systemic inflammatory response and mortality between monomicrobial and polymicrobial nBSI with Pseudomonas aeruginosa. METHODS: We performed a historical cohort study on 98 adults with P. aeruginosa (Pa) nBSI. SIRS scores were determined 2 days prior to the first positive blood culture through 14 days afterwards. Monomicrobial (n = 77) and polymicrobial BSIs (n = 21) were compared. RESULTS: 78.6% of BSIs were caused by monomicrobial P. aeruginosa infection (MPa) and 21.4% by polymicrobial P. aeruginosa infection (PPa). Median APACHE II score on the day of BSI was 22 for MPa and 23 for PPa BSIs. Septic shock occurred in 33.3% of PPa and in 39.0% of MPa (p = 0.64). Progression to septic shock was associated with death more frequently in PPa (OR 38.5, CI95 2.9-508.5) than MPa (OR 4.5, CI95 1.7-12.1). Maximal SIR (severe sepsis, septic shock or death) was seen on day 0 for PPa BSI vs. day 1 for MPa. No significant difference was noted in the incidence of organ failure, 7-day or overall mortality between the two groups. Univariate analysis revealed that APACHE II score > or = 20 at BSI onset, Charlson weighted comorbidity index > or = 3, burn injury and respiratory, cardiovascular, renal and hematologic failure were associated with death, while age, malignant disease, diabetes mellitus, hepatic failure, gastrointestinal complications, inappropriate antimicrobial therapy, infection with imipenem resistant P. aeruginosa and polymicrobial nBSI were not. Multivariate analysis revealed that hematologic failure (p < 0.001) and APACHE II score > or = 20 at BSI onset (p = 0.005) independently predicted death. CONCLUSION: In this historical cohort study of nBSI with P. aeruginosa, the incidence of septic shock and organ failure was high in both groups. Additionally, patients with PPa BSI were not more acutely ill, as judged by APACHE II score prior to blood culture positivity than those with MPa BSI. Using multivariable logistic regression analysis, the development of hematologic failure and APACHE II score > or = 20 at BSI onset were independent predictors of death; however, PPa BSI was not.

APACHE↗

Systemic inflammatory response syndrome in adult patients with nosocomial bloodstream infection due to Pseudomonas aeruginosa.

OBJECTIVES: To evaluate relationships between the inflammatory response, clinical course, and outcome of nosocomial BSI due to Pseudomonas aeruginosa. METHODS: We performed a historical cohort study on 77 adults with P. aeruginosa (Pa) nBSI to define the associated systemic inflammatory response syndrome (SIRS). We examined SIRS scores 2 days prior through 14 days after the first positive blood culture. Imipenem resistant--IRPa (n=20) and susceptible infections--ISPa (n=57) were compared. Variables significant in univariate analysis were entered into a logistic regression model. RESULTS: Seventy-four percent of BSI were ISPa and 26.0% by IRPa. Septic shock occurred in 39.0%. Crude mortality was 48.1%. There was no difference in APACHE II (AP2) scores on days -2, -1 and 0 between the ISPa and IRPa groups. Multivariate analysis revealed that AP2> or =20 at BSI onset (P<0.001) and hematologic failure (P=0.001) independently predicted death. CONCLUSIONS: In patients with P. aeruginosa nBSI, the incidence of septic shock and organ failure is high; patients with IRPa BSI are not more acutely ill prior to infection than those with ISPa BSI and outcome is not significantly different; AP2> or =20 at BSI onset and the development of hematologic failure are independent predictors of death.

Adult↗

Bloodstream infections due to Candida species in the intensive care unit: identifying especially high-risk patients to determine prevention strategies.

Nosocomial bloodstream infections due to Candida species are associated with a 40% crude (total) mortality rate in the United States. The attributable mortality rate defines the number of deaths due directly to the infection and represents the proportion of the total number of deaths influenced by the use of anti-infectives. We used 4 defined risk factors to create a conditional logistic regression model of individual patients' risk of candidemia and then examined the possibility of using a calculated risk threshold to begin treatment with anti-Candida antibiotics. We subsequently examined the number needed to treat (NNT) to prevent a single death related to bloodstream infection due to Candida species. By use of our model and assuming a 33% threshold for treating with an antibiotic, which is assumed to prevent 65% of candidal bloodstream infections, we show that the NNT would be 7 patients. Use of defined risk factors to select patients who are at high risk for candidemia and treatment with effective antibiotics would be an efficient way to reduce infection-related deaths.

Anti-Infective Agents↗

Predicting hospital rates of fluoroquinolone-resistant Pseudomonas aeruginosa from fluoroquinolone use in US hospitals and their surrounding communities.

Rates of fluoroquinolone resistance among Pseudomonas aeruginosa in hospitals are increasing, but interhospital variability is great. We sought to determine whether this variability correlated to fluoroquinolone use in hospitals and in the surrounding community. Hospital quinolone use in 1999 (24 hospitals) through 2001 (35 hospitals) was determined from billing records. The number of fluoroquinolone prescriptions within a 10-mile (approximately 16-km) radius of each hospital was determined for 1999 and 2000. Hospital fluoroquinolone use increased from 1999 through 2001, from 137 to 163 defined daily doses (DDD)/1000 patient-days (P=.01). The rate of community fluoroquinolone use also increased, from 2.3 to 2.8 DDD/1000 inhabitant-days (P<.001). Rates of fluoroquinolone-resistant P. aeruginosa increased from 29% in 1999 to 36% in 2001 (P=.003). Both community and hospital fluoroquinolone use were predictive of rates of fluoroquinolone-resistant P. aeruginosa. Levofloxacin was associated with resistance, but ciprofloxacin was not. Most of the variability in resistance rates is explained by volume of fluoroquinolone use, both in the hospital and the surrounding community.

Adolescent↗

Emerging resistance among bacterial pathogens in the intensive care unit--a European and North American Surveillance study (2000-2002).

BACKGROUND: Globally ICUs are encountering emergence and spread of antibiotic-resistant pathogens and for some pathogens there are few therapeutic options available. METHODS: Antibiotic in vitro susceptibility data of predominant ICU pathogens during 2000-2 were analyzed using data from The Surveillance Network (TSN) Databases in Europe (France, Germany and Italy), Canada, and the United States (US). RESULTS: Oxacillin resistance rates among Staphylococcus aureus isolates ranged from 19.7% to 59.4%. Penicillin resistance rates among Streptococcus pneumoniae varied from 2.0% in Germany to as high as 20.2% in the US; however, ceftriaxone resistance rates were comparably lower, ranging from 0% in Germany to 3.4% in Italy. Vancomycin resistance rates among Enterococcus faecalis were < or = 4.5%; however, among Enterococcus faecium vancomycin resistance rates were more frequent ranging from 0.8% in France to 76.3% in the United States. Putative rates of extended-spectrum beta-lactamase (ESBL) production among Enterobacteriaceae were low, <6% among Escherichia coli in the five countries studied. Ceftriaxone resistance rates were generally lower than or similar to piperacillin-tazobactam for most of the Enterobacteriaceae species examined. Fluoroquinolone resistance rates were generally higher for E. coli (6.5% - 13.9%), Proteus mirabilis (0-34.7%), and Morganella morganii (1.6-20.7%) than other Enterobacteriaceae spp (1.5-21.3%). P. aeruginosa demonstrated marked variation in beta-lactam resistance rates among countries. Imipenem was the most active compound tested against Acinetobacter spp., based on resistance rates. CONCLUSION: There was a wide distribution in resistance patterns among the five countries. Compared with other countries, Italy showed the highest resistance rates to all the organisms with the exception of Enterococcus spp., which were highest in the US. This data highlights the differences in resistance encountered in intensive care units in Europe and North America and the need to determine current local resistance patterns by which to guide empiric antimicrobial therapy for intensive care infections.

Journal Article↗

Nosocomial bloodstream infections in US hospitals: analysis of 24,179 cases from a prospective nationwide surveillance study.

BACKGROUND: Nosocomial bloodstream infections (BSIs) are important causes of morbidity and mortality in the United States. METHODS: Data from a nationwide, concurrent surveillance study (Surveillance and Control of Pathogens of Epidemiological Importance [SCOPE]) were used to examine the secular trends in the epidemiology and microbiology of nosocomial BSIs. RESULTS: Our study detected 24,179 cases of nosocomial BSI in 49 US hospitals over a 7-year period from March 1995 through September 2002 (60 cases per 10,000 hospital admissions). Eighty-seven percent of BSIs were monomicrobial. Gram-positive organisms caused 65% of these BSIs, gram-negative organisms caused 25%, and fungi caused 9.5%. The crude mortality rate was 27%. The most-common organisms causing BSIs were coagulase-negative staphylococci (CoNS) (31% of isolates), Staphylococcus aureus (20%), enterococci (9%), and Candida species (9%). The mean interval between admission and infection was 13 days for infection with Escherichia coli, 16 days for S. aureus, 22 days for Candida species and Klebsiella species, 23 days for enterococci, and 26 days for Acinetobacter species. CoNS, Pseudomonas species, Enterobacter species, Serratia species, and Acinetobacter species were more likely to cause infections in patients in intensive care units (P<.001). In neutropenic patients, infections with Candida species, enterococci, and viridans group streptococci were significantly more common. The proportion of S. aureus isolates with methicillin resistance increased from 22% in 1995 to 57% in 2001 (P<.001, trend analysis). Vancomycin resistance was seen in 2% of Enterococcus faecalis isolates and in 60% of Enterococcus faecium isolates. CONCLUSION: In this study, one of the largest multicenter studies performed to date, we found that the proportion of nosocomial BSIs due to antibiotic-resistant organisms is increasing in US hospitals.

Adolescent↗