Biomedical subjects
Publications and source records attributed to Trish M Perl.
An investigation of malaria in a US patient without recent travel established Plasmodium falciparum molecular genotype identity in 2 patients who shared a hospital room. P. falciparum can be transmitted in a hospital environment from patient to patient by blood inoculum if standard precautions are breached.
CONTEXT: Pulsatile lavage is a high-pressure irrigation treatment used increasingly in a variety of health care settings to debride wounds. Infection control precautions are not routinely used during the procedure and are not included in pulsatile lavage equipment package labeling. OBJECTIVES: To investigate an outbreak of multidrug-resistant Acinetobacter baumannii and to test the hypothesis that pulsatile lavage wound treatment was the mode of transmission for the organism. DESIGN: Outbreak case-control investigation including case identification, review of medical records, environmental cultures, and pulsed-field gel electrophoresis. SETTING: A 1000-bed tertiary care hospital in Baltimore, Md, during September and October 2003. PATIENTS: The investigation included 11 patients infected or colonized with multidrug-resistant A baumannii. Seven of these patients met the case definition for the case-control study and were compared with 28 controls randomly selected from a list of inpatients without multidrug-resistant A baumannii who had a wound care consultation. MAIN OUTCOME MEASURE: Infection or colonization with multidrug-resistant A baumannii. RESULTS: Eleven patients had cultures that grew multidrug-resistant A baumannii during the outbreak period. Of the 10 health care-associated cases, 8 had received pulsatile lavage treatment. One strain of multidrug-resistant A baumannii was recovered from all 6 pulsatile lavage patients who had isolates available for pulsed-field gel electrophoresis analysis and from multiple surfaces in the wound care area. Six of 7 cases (86%) were treated with pulsatile lavage vs 4 of 28 controls (14%) (odds ratio, 36; 95% confidence interval, 2.8-1721; P<.001). These results confirm that pulsatile lavage was a significant risk factor for acquisition of multidrug-resistant A baumannii. CONCLUSIONS: Transmission was apparently caused by dissemination of multidrug-resistant A baumannii during the pulsatile lavage procedure, resulting in environmental contamination. Appropriate infection control precautions should be used during pulsatile lavage therapy and should be included in pulsatile lavage equipment labeling.
RATIONALE: Health care-associated bloodstream infections are common in critically ill patients; however, investigators have had difficulty in quantifying the clinical impact of these infections given the high expected mortality among these patients. OBJECTIVE: To estimate the impact of health care-associated bloodstream infections on in-hospital mortality after adjusting for severity of illness at critical care admission. METHOD: A cohort of medical and surgical intensive care unit patients. MEASUREMENTS: Severity of illness at admission, bloodstream infection, and in-hospital mortality. MAIN RESULTS: Among the 2,783 adult patients, 269 developed unit-associated bloodstream infections. After adjusting for severity of illness, patients with a lower initial severity of illness who developed an infection had a greater than twofold higher risk for in-hospital mortality (hazard ratio [HR] = 2.42, 95% confidence interval [CI] 1.70, 3.44) when compared with patients without infection and with a similar initial severity of illness. In contrast, patients with a higher initial severity of illness who subsequently developed an infection did not have an increased risk for in-hospital mortality (HR = 0.96, 95%CI 0.76, 1.23) when compared with patients without infection but with a similar initial severity of illness. CONCLUSIONS: These results suggest that these infections in less ill patients have a higher attributable impact on subsequent mortality than in more severely ill patients. Focusing interventions to prevent bloodstream infections in less severely ill patients would be expected to have a greater benefit in terms of mortality reduction.
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BACKGROUND: Staphylococcus aureus nasal carriage is a risk factor for surgical-site infections (SSIs) caused by S. aureus, and eradication of carriage reduces postoperative nosocomial infections caused by it. No study has compared large groups of preoperative carriers and non-carriers to identify factors that are linked to S. aureus nasal carriage. METHODS: While conducting a clinical trial evaluating whether mupirocin prevented S. aureus SSIs, we prospectively collected data on 70 patient characteristics that might be associated with S. aureus carriage. We performed stepwise logistic regression analysis. RESULTS: Of the 4,030 patients, 891 (22%) carried S. aureus. Independent risk factors for S. aureus nasal carriage were obesity (odds ratio [OR], 1.29; 95% confidence interval [CI95], 1.11-1.50), male gender (OR, 1.29; CI95, 1.11-1.51), and a history of a cerebrovascular accident (OR, 1.53; CI95, 1.03-2.25) for all patients. Factors associated with nasal carriage varied somewhat by surgical specialty. In all groups, preoperative use of antimicrobial agents was independently associated with a lower risk of carrying S. aureus in the nares. Previously identified risk factors were not significantly associated with S. aureus nasal carriage in this large group of surgical patients. CONCLUSION: Male gender, obesity, and a history of a cerebrovascular accident were identified as risk factors for S. aureus nasal carriage. It remains to be seen whether preoperative weight loss would reduce the rate of nasal carriage. In addition, the value of screening this patient population for S. aureus nasal carriage merits further investigation.
Recent guidelines for the prevention of opportunistic infections have addressed a variety of issues germane to recipients of hematopoietic stem cell transplant. However, there are several issues regarding postexposure prophylaxis against varicella-zoster virus that remain unresolved. We address these questions and offer several consensus recommendations.
OBJECTIVE: To determine whether a multifaceted systems intervention would eliminate catheter-related bloodstream infections (CR-BSIs). DESIGN: Prospective cohort study in a surgical intensive care unit (ICU) with a concurrent control ICU. SETTING: The Johns Hopkins Hospital. PATIENTS: All patients with a central venous catheter in the ICU. INTERVENTION: To eliminate CR-BSIs, a quality improvement team implemented five interventions: educating the staff; creating a catheter insertion cart; asking providers daily whether catheters could be removed; implementing a checklist to ensure adherence to evidence-based guidelines for preventing CR-BSIs; and empowering nurses to stop the catheter insertion procedure if a violation of the guidelines was observed. MEASUREMENT: The primary outcome variable was the rate of CR-BSIs per 1,000 catheter days from January 1, 1998, through December 31, 2002. Secondary outcome variables included adherence to evidence-based infection control guidelines during catheter insertion. MAIN RESULTS: Before the intervention, we found that physicians followed infection control guidelines during 62% of the procedures. During the intervention time period, the CR-BSI rate in the study ICU decreased from 11.3/1,000 catheter days in the first quarter of 1998 to 0/1,000 catheter days in the fourth quarter of 2002. The CR-BSI rate in the control ICU was 5.7/1,000 catheter days in the first quarter of 1998 and 1.6/1,000 catheter days in the fourth quarter of 2002 (p = .56). We estimate that these interventions may have prevented 43 CR-BSIs, eight deaths, and 1,945,922 dollars in additional costs per year in the study ICU. CONCLUSIONS: Multifaceted interventions that helped to ensure adherence with evidence-based infection control guidelines nearly eliminated CR-BSIs in our surgical ICU.
BACKGROUND: It has been recommended that bronchoscopists familiarize themselves with national recommendations for bronchoscope reprocessing practices, but the extent of guideline awareness is unclear. METHODS: We distributed a survey to practicing bronchoscopists at two meetings. Questions addressed infection control issues related to bronchoscopy and specific reprocessing recommendations. RESULTS: A total of 46 surveys were completed by medical directors of bronchoscopy suites (26%) and attending bronchoscopists (74%) who had graduated from medical school a median of 22 years ago and performed a median of 19 procedures per month. Sixty-five percent of respondents, including 55% of directors, were not familiar with national reprocessing recommendations, and 39% did not know the approach to reprocessing at their own institution. Respondents who did > 20 procedures per month trended toward being more likely to be aware of guidelines (54% vs 26%, p = 0.09) and were less likely to answer "do not know" to more than one question about specific reprocessing details (25% vs 70%, p = 0.003). Seventy-eight percent of respondents did not know local practices for at least one of the reprocessing details. Forty-six percent of respondents stated their institutions followed recommendations that records be kept of the specific bronchoscope used in each case. CONCLUSIONS: Many experienced bronchoscopists are unfamiliar with national guidelines and local practices related to bronchoscope reprocessing. Publication of bronchoscope-specific, comprehensive reprocessing guidelines in the pulmonary literature may help increase familiarity with this crucial process.
We evaluated antimicrobial exposure, discharge diagnoses, or both to identify surgical site infections (SSI). This retrospective cohort study in 13 hospitals involved weighted, random samples of records from 8,739 coronary artery bypass graft (CABG) procedures, 7,399 cesarean deliveries, and 6,175 breast procedures. We compared routine surveillance to detection through inpatient antimicrobial exposure (> 9 days for CABG, > 2 days for cesareans, and > 6 days for breast procedures), discharge diagnoses, or both. Together, all methods identified SSI after 7.4% of CABG, 5.0% of cesareans, and 2.0% of breast procedures. Antimicrobial exposure had the highest sensitivity, 88%-91%, compared with routine surveillance, 38%-64%. Diagnosis codes improved sensitivity of detection of antimicrobial exposure after cesareans. Record review confirmed SSI after 31% to 38% of procedures that met antimicrobial surveillance criteria. Sufficient antimicrobial exposure days, together with diagnosis codes for cesareans, identified more postoperative SSI than routine surveillance methods. This screening method was efficient, readily standardized, and suitable for most hospitals.
Infections caused by Staphylococcus aureus with reduced vancomycin susceptibility (SA-RVS; minimum inhibitory concentration [MIC], >or=4 microg/mL), including vancomycin-intermediate S. aureus (VISA; MIC, 8 microg/mL), are a new clinical and public health dilemma. Prospective surveillance and a nested case-control study of patients in the United States infected with SA-RVS was conduced from March 1999 through December 2000. Control patients were persons infected with oxacillin-resistant S. aureus (MIC of vancomycin, <or=2 microg/mL). Among 19 case patients, 4 infections were due to VISA and 15 were due to non-VISA SA-RVS. Case patients with and those without VISA infection had similar clinical presentations and outcomes; the overall attributable mortality rate was 63%. Isolates recovered from case patients had heterogeneous pulsed-field gel electrophoresis banding patterns, regardless of the MIC of vancomycin. Neither dialysis nor chronic renal failure were predictive of case status compared with control status. Independent risk factors for being a case patient included antecedent vancomycin use and prior oxacillin-resistant S. aureus infection 2 or 3 months before the current infection.
BACKGROUND: Endoscopes, including bronchoscopes, are the medical devices most frequently associated with outbreaks of nosocomial infections. We investigated an outbreak of Pseudomonas aeruginosa infections after bronchoscopic procedures. METHODS: Microbiologic results were reviewed to determine the rates of recovery of P. aeruginosa from bronchoalveolar-lavage specimens. Environmental samples from endoscopes and the endoscopy suite were cultured. Medical records were reviewed to identify infections in the 14 days after a bronchoscopy. RESULTS: The rate of recovery of P. aeruginosa from bronchoalveolar-lavage specimens obtained with use of endoscopy-suite bronchoscopes increased from 10.4 percent at base line to 31.0 percent during the outbreak (relative risk, 2.97; 95 percent confidence interval, 2.28 to 3.90). Cultures of samples from three bronchoscopes grew P. aeruginosa, whereas cultures of samples from the environment, instrument-cleaning machines, and gastrointestinal endoscopes did not. The three bronchoscopes had been part of a nationwide recall. A total of 414 patients underwent bronchoscopy during the outbreak, and there were 48 respiratory tract and bloodstream infections among 39 of these patients (9.4 percent). In 32 infections (66.7 percent), P. aeruginosa was confirmed as a potentially causative organism. Exposure to a potentially contaminated bronchoscope may have had a role in the death of three patients. The rate of recovery of P. aeruginosa returned to base line after the instruments were removed from service. CONCLUSIONS: This large outbreak of P. aeruginosa infections related to bronchoscopy was apparently caused by a loose biopsy-port cap in the bronchoscopes. Instrument safety and surveillance methods for bronchoscopy must be improved, and better recall procedures are needed for medical devices.
BACKGROUND: Health care-related infections cause significant patient morbidity and mortality rates and add excess costs that frequently are not reimbursed. Staphylococcus aureus has long been recognized as an important pathogen in human disease and is the most common cause of nosocomial infections. METHOD: The objective of this review of the English language literature and a MEDLINE search was to describe recent advances in the prevention of S aureus health care-related infections that are attributable to patients' endogenous colonization. The ecologic niche of S aureus is the anterior nares and nasal carriage increases the risk of the development of a surgical-site, lower respiratory tract, or bloodstream infection. S aureus carriers have a 2- to 9-fold increased risk of the development of a surgical-site or intravenous catheter infection. RESULTS: Three treatment strategies may eliminate nasal carriage: locally applied antibiotics or disinfectants, systemic antibiotics, and bacterial interference. Among these strategies, locally applied or systemic antibiotics are used most commonly. Nasal ointments or sprays and oral antibiotics have variable efficacy, and their use frequently results in antimicrobial resistance among S aureus strains. Of the commonly used agents, mupirocin (pseudomonic acid) ointment has been shown to be 97% effective in reducing S aureus nasal carriage. In a recently published randomized, double-blind, placebo-controlled trial to determine whether intranasal mupirocin reduced the rate of S aureus-infected surgical-site and other S aureus health care-related infections; 4% of S aureus nasal carriers who received mupirocin acquired S aureus health care-related infections compared with 7.7% of S aureus nasal carriers who received placebo (P=.02). The S aureus surgical-site infection rate was not reduced significantly, but carriers who received mupirocin before cardiothoracic or general surgery operations had almost 50% fewer S aureus surgical-site infections than carriers who received placebo. In this setting resistance rarely has been reported. CONCLUSIONS: Given the importance of S aureus nosocomial infections and the increased risk of S aureus nasal carriage in patients with health care-related infections, investigators must study cost-effective strategies to further prevent certain types of health care-related infections or nosocomial infections that occur in specific settings. One potential strategy is to decrease or eliminate S aureus nasal carriage among certain patient populations or in certain healthcare settings.
OBJECTIVE: To determine the prevalence of central venous catheter (CVC) use among patients both within and outside the ICU setting. DESIGN: A 1-day prevalence survey of CVC use among adult inpatients at six medical centers participating in the Prevention Epicenter Program of the CDC. Using a standardized form, observers at each Epicenter performed a hospital-wide survey, collecting data on CVC use. SETTING: Inpatient wards and ICUs of six large urban teaching hospitals. RESULTS: At the six medical centers, 2,459 patients were surveyed; 29% had CVCs. Among the hospitals, from 43% to 80% (mean, 59.3%) of ICU patients and from 7% to 39% (mean, 23.7%) of non-ICU patients had CVCs. Despite the lower rate of CVC use on non-ICU wards, the actual number of CVCs outside the ICUs exceeded that of the ICUs. Most catheters were inserted in the subclavian (55%) or jugular (22%) site, with femoral (6%) and peripheral (15%) sites less commonly used. The jugular (33.0% vs 16.6%; P < .001) and femoral (13.8% vs 2.7%; P < .001) sites were more frequently used in ICU patients, whereas peripherally inserted (19.9% vs 5.9%; P < .001) and subclavian (60.7% vs 47.3%; P < .001) catheters were more commonly used in non-ICU patients. CONCLUSIONS: Current surveillance and infection control efforts to reduce morbidity and mortality associated with bloodstream infections concentrate on the high-risk ICU patients with CVCs. Our survey demonstrated that two-thirds of identified CVCs were not in ICU patients and suggests that more efforts should be directed to patients with CVCs who are outside the ICU.
OBJECTIVE: To determine the impact of vancomycin-resistant enterococcal bacteremia on patient outcomes and costs by assessing mortality, excess length of stay, and charges attributable to it. DESIGN: A population-based, matched, historical cohort study. SETTING: A 1,025-bed, university-based teaching facility and referral hospital. PATIENTS: Two hundred seventy-seven vancomycin-resistant enterococcal bacteremia case-patients and 277 matched control-patients identified between 1993 and 2000. RESULTS: The crude mortality rate was 50.2% and 19.9% for case-patients and control-patients, respectively, yielding a mortality rate of 30.3% attributable to vancomycin-resistant enterococcal bacteremia. The excess length of hospital stay attributable to vancomycin-resistant enterococcal bacteremia was 17 days, of which 12 days were spent in intensive care units. On average, dollars 77,558 in extra charges was attributable to each vancomycin-resistant enterococcal bacteremia. To adjust for severity of illness, 159 pairs of case-patients and control-patients, who had the same severity of illness (All Patient Refined-Diagnosis Related Group complexity level), were further analyzed. When patients were stratified by severity of illness, the crude mortality rate was 50.3% among case-patients compared with 27.7% among control-patients, accounting for an attributable mortality rate of 22.6%. Attributable excess length of stay and charges were 17 days and dollars 81,208, respectively. CONCLUSION: Vancomycin-resistant enterococcal bacteremia contributes significantly to excess mortality and economic loss, once severity of illness is considered. Efforts to prevent these infections will likely be cost-effective.
OBJECTIVE: To assess the safety and efficacy of a chlorine dioxide water treatment system in controlling Legionella in a hospital water supply. DESIGN: For 17 months following installation of the system, we performed regular water cultures throughout the building, assessed chlorine dioxide and chlorite levels, and monitored metal corrosion. RESULTS: Sites that grew Legionella species decreased from 41% at baseline to 4% (P = .001). L. anisa was the only species recovered and it was found in samples of both hot and cold water. Levels of chlorine dioxide and chlorite were below Environmental Protection Agency (EPA) limits for these chemicals in potable water. Further, enhanced carbon filtration effectively removed the chemicals, even at chlorine dioxide levels of more than twice what was used to treat the water. After 9 months, corrosion of copper test strips exposed to the chlorine dioxide was not higher than that of control strips. During the evaluation period, there were no cases of nosocomial Legionella in the building with the system, whereas there was one case in another building. CONCLUSIONS: Our results indicate that operation of a chlorine dioxide system effectively removed Legionella species from a hospital water supply. Furthermore, we found that the system was safe, as levels of chlorine dioxide and chlorite were below EPA limits. The system did not appear to cause increased corrosion of copper pipes. Our results indicate that chlorine dioxide may hold promise as a solution to the problem of Legionella contamination of hospital water supplies.
Nosocomial acquisition of microorganisms resistant to multiple antibiotics represents a threat to patient safety. Here we review the mechanisms that have allowed highly resistant strains belonging to the Enterococcus genus to proliferate within our health-care institutions. These mechanisms indicate that decreasing the prevalence of resistant organisms requires active surveillance, adherence to vigorous isolation, hand hygiene and environmental decontamination measures, and effective antibiotic stewardship. We suggest how to tailor such a complex, multidisciplinary program to the needs of a particular health-care setting so as to maximize cost-effectiveness.
We conducted a retrospective study of the clinical aspects of bacteremia caused by methicillin-resistant Staphylococcus aureus (MRSA) with heterogeneously reduced susceptibility to vancomycin. Bloodstream MRSA isolates were screened for reduced susceptibility by using brain-heart infusion agar, including 4 mg/L vancomycin with and without 4% NaCl. Patients whose isolates exhibited growth (case-patients) were compared with those whose isolates did not (controls) for demographics, coexisting chronic conditions, hospital events, antibiotic exposures, and outcomes. Sixty-one (41%) of 149 isolates exhibited growth. Subclones from 46 (75%) of these had a higher MIC of vancomycin than did their parent isolates. No isolates met criteria for vancomycin heteroresistance. No differences in potential predictors or in outcomes were found between case-patients and controls. These data show that patients with vancomycin-susceptible MRSA bacteremia have similar baseline clinical features and outcomes whether or not their bacterial isolates exhibit growth on screening media containing vancomycin.
Vancomycin-resistant Enterococcus faecium (VRE) is a common nosocomial isolate, especially among patients with cancer. VRE infections have substantial attributable mortality among patients with cancer. The purpose of this study was to identify risk factors for developing bloodstream infection with VRE in patients with cancer who are colonized with VRE. VRE colonization was prospectively identified in 197 patients with cancer during 4-year period, of whom 179 (91%) had complete records for evaluation. Of these 179 patients, 24 (13.4%) developed hospital-acquired VRE bloodstream infections. Risk factors for VRE bloodstream infection included vancomycin use (relative risk [RR], 1.98; 95% confidence interval [CI], 1.25-3.14), diabetes mellitus (RR, 3.91; 95% CI, 1.20-12.77), gastrointestinal procedures (RR, 4.56; 95% CI, 1.05-19.7), and acute renal failure (RR, 3.10; 95% CI, 1.07-8.93). Strategies for preventing VRE bloodstream infection in VRE-colonized patients with cancer should include limiting vancomycin use and, perhaps, gastrointestinal procedures.