Showing papers in "Infection Control and Hospital Epidemiology in 2001"

Nasal Carriage as a Source of Staphylococcus aureus Bacteremia

Abstract: of antibiotics, whether there was an explicit note in the medical chart in which the physician diagnosed a true bacteremia, and the Centers for Disease Control surveillance criteria for primary bloodstream infection. Agreement between same-strain bacteremia and each definition was examined, based on the assumption that most true infections should be the result of a single strain. The study sample consisted of 42 patients and 106 isolates. Nineteen of the 42 bacteremias (45%) were the same strain. Classification of bacteremias as same-strain correlated poorly with all three clinical assessments (range of percentage agreement, 50%-57%; range of kappa statistic, 0.01-0.15). There were both false-positive and false-negative errors. Patients with three or more positive blood cultures were more likely to have same-strain bacteremia than those with only two positive cultures (11/15 [73%] vs 8/27 [30%], P=.006). Pulsed-field gel electrophoresis was more discriminating than AP PCR (percentage agreement, 83%; kappa, 0.67). The authors concluded that molecular typing correlated poorly with clinical criteria for true bacteremia, suggesting either that true bacteremias are frequently the result of multiple strains or that the commonly used clinical criteria are not accurate for distinguishing contamination from true bacteremia. Vancomycin treatment of clinically defined coagulase-negative staphylococcal bacteremia may frequently be unnecessary. FROM: Seo SK, Venkataraman L, DeGirolami PC, Samore MH. Molecular typing of coagulase-negative staphylococci from blood cultures does not correlate with clinical criteria for true bacteremia. Am J Med 2000;109:697-704.

Guidelines for the management of intravascular catheter-related infections.

Abstract: These guidelines from the Infectious Diseases Society of America (IDSA), the American College of Critical Care Medicine (for the Society of Critical Care Medicine), and the Society for Healthcare Epidemiology of America contain recommendations for the management of adults and children with, and diagnosis of infections related to, peripheral and nontunneled central venous catheters (CVCs), pulmonary artery catheters, tunneled central catheters, and implantable devices. The guidelines, written for clinicians, contain IDSA evidence-based recommendations for assessment of the quality and strength of the data. Recommendations are presented according to the type of catheter, the infecting organism, and the associated complications. Intravascular catheter-related infections are a major cause of morbidity and mortality in the United States. Coagulase-negative staphylococci, Staphylococcus aureus, aerobic gram-negative bacilli, and Candida albicans most commonly cause catheter-related bloodstream infection. Management of catheter-related infection varies according to the type of catheter involved. After appropriate cultures of blood and catheter samples are done, empirical iv antimicrobial therapy should be initiated on the basis of clinical clues, the severity of the patient's acute illness, underlying disease, and the potential pathogen (s) involved. In most cases of nontunneled CVC-related bacteremia and fungemia, the CVC should be removed.

The association of diabetes and glucose control with surgical-site infections among cardiothoracic surgery patients.

Abstract: Objective: To assess the importance of diabetes, diabetes control, hyperglycemia, and previously undiagnosed diabetes in the development of surgical-site infections (SSIs) among cardiothoracic surgery patients. Setting: A 540-bed tertiary-care university-affiliated hospital. Design: Prospective cohort and case-control studies. Patients: All patients having cardiothoracic surgery between November 1998 and September 1999 were eligible for participation. One thousand patients had preoperative hemoglobin Ale determinations. Seventy-four patients with SSIs were identified. Results: Diabetes (odd ratio [OR], 2.76; P<.001) and postoperative hyperglycemia (OR, 2.02; P=.007) were independently associated with development of SSIs. Among known diabetics, elevated hemoglobin Ale values were not associated with a statistically significantly increased risk of infection; the mean Ale value was 8.44% among those with infections compared with 7.80% for those without (P=.09). Forty-two (6%) of 700 patients without prior diabetes history had evidence of undiagnosed diabetes; their infection rate was comparable to that of known diabetics (3/42 [796] vs 17/300 [6%]; P=.72). An additional 30% of nondiabetics had elevated hemoglobin Ale determinations or perioperative hyperglycemia. Conclusions: Postoperative hyperglycemia and previously undiagnosed diabetes are associated with development of SSIs among cardiothoracic surgery patients. Screening for diabetes and hyperglycemia among patients having cardiothoracic surgery may be warranted to prevent postoperative and chronic complications of this metabolic abnormality.

Development of Minimum Criteria for the Initiation of Antibiotics in Residents of Long-Term–Care Facilities: Results of a Consensus Conference

Abstract: Establishing a clinical diagnosis of infection in residents of long-term-care facilities (LTCFs) is difficult. As a result, deciding when to initiate antibiotics can be particularly challenging. This article describes the establishment of minimum criteria for the initiation of antibiotics in residents of LTCFs. Experts in this area were invited to participate in a consensus conference. Using a modified delphi approach, a questionnaire and selected relevant articles were sent to participants who were asked to rank individual signs and symptoms with respect to their relative importance. Using the results of the weighting by participants, a modification of the nominal group process was used to achieve consensus. Criteria for initiating antibiotics for skin and soft-tissue infections, respiratory infections, urinary infections, and fever where the focus of infection is unknown were developed.

The economic impact of methicillin-resistant Staphylococcus aureus in Canadian hospitals.

Abstract: Objectives: To determine the costs associated with the management of hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA), and to estimate the economic burden associated with MRSA in Canadian hospitals. Design: Patient-specific costs were used to determine the attributable cost of MRSA associated with excess hospitalization and concurrent treatment. Excess hospitalization for infected patients was identified using the Appropriateness Evaluation Protocol, a criterion-based chart review process to determine the need for each day of hospitalization. Concurrent treatment costs were identified through chart review for days in isolation, antimicrobial therapy, and MRSA screening tests. The economic burden to Canadian hospitals was estimated based on 3,167,521 hospital discharges for 1996 and 1997 and an incidence of 4.12 MRSA cases per 1,000 admissions. Setting: A tertiary-care, university-affiliated teaching hospital in Toronto, Ontario, Canada. Patients: Inpatients with at least one culture yielding MRSA between April 1996 and March 1998. Results: A total of 20 patients with MRSA infections and 79 colonized patients (with 94 admissions) were identified. This represented a rate of 2.9 MRSA cases per 1,000 admissions. The mean number of additional hospital days attributable to MRSA infection was 14, with 11 admissions having at least 1 attributable day. The total attributable cost to treat MRSA infections was $59 million annually. Conclusions: These results indicate that there is a substantial economic burden associated with MRSA in Canadian hospitals. These costs will continue to rise if the incidence of MRSA increases further.

Risk Factors for Surgical-Site Infections Following Cesarean Section

Abstract: Objective: To identify risk factors associated with surgical-site infections (SSIs) following cesarean sections. Design: Prospective cohort study. Setting: High-risk obstetrics and neonatal tertiary-care center in upstate New York. Patients: Population-based sample of 765 patients who underwent cesarean sections at our facility during 6-month periods each year from 1996 through 1998. Methods: Prospective surgical-site surveillance was conducted using methodology of the National Nosocomial Infections Surveillance System. Infections were identified during admission, within 30 days following the cesarean section, by read-mission to the hospital or by a postdischarge survey. Results: Multiple logistic-regression analysis identified four factors independently associated with an increased risk of SSI following cesarean section: absence of antibiotic prophylaxis (odds ratio [OR], 2.63; 95% confidence interval [CI95], 1.50-4.6; P=.008); surgery time (OR, 1.01; CI95, 1.00-1.02; P=.04); <7 prenatal visits (OR, 3.99; CI95, 1.74-9.15; P=.001); and hours of ruptured membranes (OR, 1.02; CI95,1.01-1.03; P=.04). Patients given antibiotic prophylaxis had significantly lower infection rates than patients who did not receive antibiotic prophylaxis (F=02), whether or not active labor or ruptured membranes were present. Conclusion: Among the variables identified as risk factors for SSI, only two have the possibility to be changed through interventions. Antibiotic prophylaxis would benefit all cesarean patients regardless of active labor or ruptured membranes and would decrease morbidity and length of stay. Women's healthcare professionals also must continue to encourage pregnant women to start prenatal visits early in the pregnancy and to maintain scheduled visits throughout the pregnancy to prevent perinatal complications, including postoperative infection.

Contamination of gowns, gloves, and stethoscopes with vancomycin-resistant enterococci.

Abstract: Objective:To measure directly the rate of contamination, during routine patient examination, of gowns, gloves, and stethoscopes with vancomycin-resistant enterococci (VRE).Setting:A large, academic, tertiary-care hospital.Patients:Between January 1997 and December 1998, 49 patients colonized or infected with VRE were entered in the study.Design:After routine examination, the examiner's glove fingertips, gown (the umbilical region and the cuffs), and stethoscope diaphragm were pressed onto Columbia colistin-nalidixic acid (CNA) agar plates with 5% sheep blood plus vancomycin 6 ug/mL. The stethoscope diaphragm was sampled again after cleaning with a 70% isopropanol wipe.Results:VRE were isolated from at least 1 examiner site (gloves, gowns, or stethoscope) in 33 (67%) of 49 cases. Gloves were contaminated in 63%, gowns in 37%, and stethoscopes in 31%. All three items were positive for VRE in 24%. One case each had stethoscope and gown contamination without glove contamination. Only 1 (2%) of 49 stethoscopes was positive after wiping with an alcohol swab. Contamination at any site was more likely when the patient had a colostomy or ileostomy. Patients identified by rectal-swab culture alone were as likely to contaminate their examiners as were those identified by clinical specimens.Conclusions:Our study revealed a high rate of examiner contamination with VRE. The similar risk of contamination identified by surveillance and clinical cases reinforces concerns that patients not known to be colonized with VRE could serve as sources for dissemination. Wiping with alcohol is effective in decontaminating stethoscopes.

A review of single-use and reusable gowns and drapes in health care.

Abstract: Gowns and drapes are used widely in healthcare facilities. Gowns have been used to minimize the risk of disease acquisition by healthcare providers, to reduce the risk of patient-to-patient transmission, and during invasive procedures to aid in maintaining a sterile field. Drapes have been used during invasive procedures to maintain the sterility of environmental surfaces, equipment, and patients. This article reviews the use of gowns and drapes in healthcare facilities, including the characteristics, costs, benefits, and barrier effectiveness of single-use and reusable products. Currently, gowns protect healthcare personnel performing invasive procedures from contact with bloodborne pathogens. Although gowns have been recommended to prevent patient-to-patient transmission in certain settings (eg, neonatal intensive care unit) and for certain patients (eg, those infected with vancomycin-resistant enterococci), scientific studies have produced mixed results of their efficacy. While appropriate use of drapes during invasive procedures is recommended widely as an aid in minimizing contamination of the operative field, the efficacy of this practice in reducing surgical-site infections has not been assessed by scientific studies. Based on an evaluation of the functional requirements, environmental impact, and economics of gowns and drapes, clear superiority of either reusable or single-use gowns and drapes cannot be demonstrated. The selection of particular gowns and drapes by individual healthcare facilities requires an assessment of the facility's requirements, available products, and costs and should be based on the desired characteristics of an ideal gown or drape as defined in this paper.

Tap water colonization with Pseudomonas aeruginosa in a surgical intensive care unit (ICU) and relation to Pseudomonas infections of ICU patients.

Abstract: Water faucets on a surgical intensive care ward were examined prospectively as a source of Pseudomonas aeruginosa infections. All water outlets harbored distinct genotypes of P aeruginosa over prolonged time periods. Over a period of 7 months, 5 (29%) of 17 patients were infected with P aeruginosa genotypes also detectable in tap water.

A hospital epidemic of vancomycin-resistant Enterococcus: risk factors and control.

Abstract: OBJECTIVE: To determine risk factors for vancomycin-resistant Enterococcus (VRE) colonization during a hospital outbreak and to evaluate Centers for Disease Control and Prevention (CDC)-recommended control measures. DESIGN: Epidemiological study involving prospective identification of colonization and a case-control study. SETTING: A university hospital. PARTICIPANTS: Patients on eight wards involved in outbreak from late 1994 through early 1995. METHODS: Cases were matched by ward and culture date with up to two controls. Risk factors were evaluated with four multivariate models using conditional logistic regression. The first evaluated proximity to other VRE patients and isolation status. The second evaluated proximity to unisolated VRE cases and three variables independently predictive after adjustment for proximity. The third evaluated seven significant univariate predictors in addition to proximity to unisolated VRE in backward, stepwise logistic regression. The fourth assessed proximity to VRE with all other variables collected, clustered in a principal components analysis. Pulsed-field gel electrophoresis was performed to assess clonality of two outbreak strains. RESULTS: The incidence of transmission declined significantly after CDC guidelines were implemented. Proximity to unisolated VRE cases during the prior week was a significant predictor of acquisition in each of four multivariate models. Other significant risk factors in multivariate models included a history of major trauma and treatment with metronidazole. Pulsed-field gel electrophoresis confirmed the clonality of two outbreak strains. CONCLUSIONS: VRE was transmitted between patients during a hospital epidemic, with proximity to previously unisolated VRE patients being an important risk factor. Weekly surveillance cultures and contact isolation of colonized patients significantly reduced spread (Infect Control Hosp Epidemiol 2001;22:140-147).

Colonization with methicillin-resistant Staphylococcus aureus in ICU patients: morbidity, mortality, and glycopeptide use.

Abstract: OBJECTIVE: To determine the impact of methicillin-resistant Staphylococcus aureus (MRSA) colonization on the occurrence of S aureus infections (methicillin-resistant and methicillin-susceptible), the use of glycopeptides, and outcome among intensive care unit (CU) patients DESIGN: Prospective observational cohort survey SETTING: A medical-surgical ICU with 10 single-bed rooms in a 460-bed, tertiary-care, university-affiliated hospital PATIENTS: A total of 1,044 ICU patients were followed for the detection of MRSA colonization from July 1, 1995, to July, 1 1998 METHODS: MRSA colonization was detected using nasal samples in all patients plus wound samples in surgical patients within 48 hours of admission or within the first 48 hours of ICU stay and weekly thereafter MRSA infections were defined using Centers for Disease Control and Prevention standard definitions, except for ventilator-associated pneumonia and catheter-related infections, which were defined by quantitative distal culture samples RESULTS: One thousand forty-four patients (70% medical patients) were included in the analysis Mean age was 61+/-18 years; mean Simplified Acute Physiologic Score (SAPS) II was 364+/-20; and median ICU stay was 4 (range, 1-193) days Two hundred thirty-one patients (22%) died in the ICU Fifty-four patients (51%) were colonized with MRSA on admission, and 52 (49%) of 1,044 acquired MRSA colonization in the ICU Thirty-five patients developed a total of 42 S aureus infections (32 MRSA, 10 methicillin-susceptible) After factors associated with the development of an S aureus infection were adjusted for in a multivariate Cox model (SAPS II >36: hazard ratio [HR], 164; P=09; male gender: HR, 22; P=05), MRSA colonization increased the risk of S aureus infection (HR, 384; P=0003) MRSA colonization did not influence ICU mortality (HR, 101; P=94) Glycopeptides were used in 114% of the patients (119/1,044) for a median duration of 5 days For patients with no colonization, MRSA colonization on admission, and ICU-acquired MRSA colonization, respectively, glycopeptide use per 1,000 hospital days was 377, 2352, and 1183 days MRSA colonization per se increased by 33-fold the use of glycopeptides in MRSA-colonized patients, even when an MRSA infection was not demonstrated, compared to non-colonized patients CONCLUSIONS: In our unit, MRSA colonization greatly increased the risk of S aureus infection and of glycopeptide use in colonized and non-colonized patients, without influencing ICU mortality MRSA colonization influenced glycopeptide use even if an MRSA infection was not demonstrated; thus, an MRSA control program is warranted to decrease vancomycin use and to limit glycopeptide resistance in gram-positive cocci

Epidemiology of surgical-site infections diagnosed after hospital discharge: a prospective cohort study.

Abstract: Objective:To study postoperative infections in hospital and after discharge, and to identify the risk factors for such infections.Design:Prospective cohort study, with telephone follow-up for 1 month after hospital discharge.Setting:The general surgery service of a tertiary hospital in Spain.Main Outcome Measure:In-hospital and postdischarge surgical-site infection (SSI), always confirmed by a physician.Results:Of the 1,506 patients initially enrolled, 29 died during hospital stay, and 33 were lost to postdischarge follow-up. An SSI was identified prior to discharge in 123 patients and after discharge in 103. For several variables (age, serum albumin, glycemia, lengths of preoperative and postoperative hospital stay, etc), there were no differences between patients with postdischarge SSI and noninfected patients; however, there were differences detected between patients with postdischarge SSI and in-hospital SSI, as well as between patients with in-hospital SSI and noninfected patients. The analysis of risk factors showed that most predictors for in-hospital SSI did not behave in the same manner for postdischarge SSI. Stepwise logistic regression only identified chemoprophylaxis, age (advanced age was a preventive factor), and body mass index as independent risk factors for postdischarge SSI. Differences in risk factors between in-hospital and postdischarge SSIs remained even after controlling for time from operation to diagnosis.Conclusions:Most predictors of in-hospital SSI were not predictors of postdischarge SSI.

The chronic indwelling catheter and urinary infection in long-term-care facility residents.

Abstract: From 5% to 10% of residents of long-term-care facilities have urinary drainage managed with chronic indwelling catheters. These residents are always bacteriuric, usually with a complex microbiological flora of two to five organisms and a biofilm on the catheter that may contribute to obstruction. Residents with chronic indwelling catheters have increased morbidity from urinary infection compared to bacteriuric residents without chronic catheters. The most effective means to prevent infection is limitation of chronic indwelling catheter use. While appropriate catheter care and infection control precautions are recommended in managing these patients, the impact of these practices on the occurrence of urinary infection or prevention of symptomatic episodes has not been evaluated. Symptomatic infection can likely be prevented by attention to catheter care, including early recognition and replacement of obstructed catheters and prevention of catheter trauma. Appropriate use of prophylactic antimicrobial therapy prior to invasive genitourinary procedures is also necessary. Asymptomatic bacteriuria should not be treated. When symptomatic episodes occur, patients should be evaluated clinically and microbiologically and treated with appropriate antimicrobial therapy. Further technological advances in catheter material and urine drainage will be needed to have a substantial impact on the frequency of urinary infection with chronic catheter use.

HACCP and food hygiene in hospitals: knowledge, attitudes, and practices of food-services staff in Calabria, Italy. Collaborative Group.

Abstract: Objectives:To determine adherence to Hazard Analysis and Critical Control Points (HACCP) methods and to evaluate knowledge, attitudes, and practices of food-services staff with regard to food hygiene in hospitals.Design:A survey.Participants:Hospital medical directors and food-services staff of 36 hospitals in Calabria, Italy.Methods:A questionnaire about hospital characteristics, food-services organization, and measures and procedures for the control and prevention of foodborne diseases was sent to medical directors; a questionnaire about demographic and practice characteristics, knowledge, attitudes, and behaviors about control and prevention of foodborne diseases was sent to food-services staff. Multiple logistic regression analysis was performed.Results:Only 54% of the 27 responding hospitals were using the HACCP system and, of those using HACCP, 79% adopted a food-hygiene–practice manual; more than one half already had developed written procedures for food storage, personal hygiene, cleaning and disinfection; one half or less performed microbiological assessment of foods and surfaces. Of the 290 food-services staff who responded, 78.8% were aware of the five leading food-borne pathogens; this knowledge was significantly higher among those with a higher educational level and those who worked in hospitals that had implemented the HACCP system. Younger staff and those who had attended continuing educational courses about food hygiene and hospital foodborne diseases had a significantly higher knowledge of safe temperatures for food storage. A positive attitude toward foodborne-diseases prevention was reported by the great majority, and it was significantly higher in older respondents and in those working in hospitals with a lower number of beds. Only 54.9% of those involved in touching or serving unwrapped raw or cooked foods routinely used gloves during this activity; this practice was significantly greater among younger respondents and in those working in hospitals using HACCP.Conclusion:Full implementation of the HACCP system and infection control policies in hospital food services is needed.

Appropriateness of use of indwelling urinary catheters in patients admitted to the medical service.

Abstract: Of 836 medical admissions evaluated over a 1-month period, 89 (10.7%) had a urinary catheter placed within 24 hours; 34 placements (38%) had no justifiable indication. Risk for inappropriate catheterization was independent of age, gender, functional status, and mental status at admission. Preventive measures should focus on increasing awareness among healthcare providers.

In vitro and in vivo efficacy of catheters impregnated with antiseptics or antibiotics: evaluation of the risk of bacterial resistance to the antimicrobials in the catheters.

Abstract: Objective: To compare the efficacy of a new antiseptic catheter containing silver sulfadiazine and chlorhexidine on the external surface and chlorhexidine in the lumens to an antibiotic catheter impregnated with minocycline and rifampin on its external and luminal surfaces. Design: Experimental trial. Methods: Antimicrobial spectrum of catheters was determined by zones of inhibition. Resistance to luminal colonization was tested in vitro by locking catheter lumens with Staphylococcus epidermidis or Staphylococcus aureus culture after 7 days of perfusion. In vitro development of resistance to the antiseptic or antibiotic combination used in catheters was investigated. In vivo efficacy was tested (rat subcutaneous model) by challenge with sensitive or antibiotic-resistant bacteria. Results: Antiseptic and antibiotic catheters exhibited broad-spectrum action. However, antibiotic catheters were not effective against Candida species and Pseudomonas aeruginosa. Both catheters prevented luminal colonization. Compared to controls, both test catheters resisted colonization when challenged with S aureus 7 and 14 days' postimplant (P<.05). Repeated in vitro exposure of S epidermidis culture to the antibiotic and antiseptic combinations led to small increases in the minimum inhibitory concentration (15 times and 2 times, respectively). Unlike the antibiotic catheter, the in vitro and in vivo activity of the antiseptic catheter was unaffected by the resistance profile of the test organism. Antiseptic catheters were more effective than antibiotic catheters in preventing colonization by rifampin-resistant S epidermidis in vivo (P<.05). Conclusions: Antiseptic and antibiotic catheters exhibit similar efficacy; however, when challenged with a rifampin-resistant strain, the antibiotic catheter appeared to be more susceptible to colonization than the antiseptic device.

An outbreak of imipenem-resistant Acinetobacter baumannii in critically ill surgical patients.

Abstract: Objective To describe an outbreak of imipenem-resistant Acinetobacter baumannii (IR-Ab) and the measures for its control, and to investigate risk factors for IR-Ab acquisition. Design An observational and a case-control study. Setting A surgical intensive care unit (ICU) in a university tertiary care hospital. Methods After admission to the ICU of an IR-Ab-positive patient, patients were prospectively screened for IR-Ab carriage upon admission and then once a week. Environmental cleaning and barrier safety measures were used for IR-Ab carriers. A case-control study was performed to identify factors associated with IR-Ab acquisition. Cases were patients who acquired IR-Ab. Controls were patients who were hospitalized in the ICU at the same time as cases and were exposed to IR-Ab for a similar duration as cases. The following variables were investigated as potential risk factors: baseline characteristics, scores for severity of illness and therapeutic intervention, presence and duration of invasive procedures, and antimicrobial administration. Results Beginning in May 1996, the outbreak involved 17 patients over 9 months, of whom 12 acquired IR-Ab (cases), 4 had IR-Ab isolates on admission to the ICU, and 1 could not be classified. Genotypic analysis identified two different IR-Ab isolates, responsible for three clusters. Ten of the 12 nosocomial cases developed infection. Control measures included reinforcement of barrier safety measures, limitation of the number of admissions, and thorough environmental cleaning. No new case was identified after January 1997. Eleven of the 12 cases could be compared to 19 controls. After adjustment for severity of illness, a high individual therapeutic intervention score appeared to be a risk factor for IR-Ab acquisition. Conclusion The outbreak ended after strict application of control measures. Our results suggest that high work load contributes to IR-Ab acquisition.

Quinolone use as a risk factor for nosocomial Clostridium difficile-associated diarrhea.

Abstract: Objective:To determine modifiable risk factors for nosocomial Clostridium difficile-associated diarrhea (CDAD).Design:Case-control study.Setting:300-bed tertiary-care hospital.Participants:Hospital inpatients present during the 3-month study period.Methods:Case-patients identified with nosocomial CDAD over the study period were compared to two sets of control patients: inpatients matched by age, gender, and date of admission; and inpatients matched by duration of hospital stay. Variables including demographic data, comorbid illnesses, antibiotic exposure, and use of gastrointestinal medications were assessed for case- and control-patients. Conditional logistic regression was performed to identify risk factors for nosocomial CDAD.Results:27 case-patients were identified and were compared to the two sets of controls (1:1 match for each comparison set). For the first set of controls, use of ciprofloxacin (odds ratio [OR], 5.5; 95% confidence interval [CI95], 1.2-24.8; P=.03) was the only variable that remained significant in the multivariable model. For the second set of controls, prior exposure to cephalosporins (OR, 6.7; CL,5, 1.3-33.7; P=.02) and to ciprofloxacin (OR, 9.5; CI95, 1.01-88.4; P=.05) were kept in the final model.Conclusions:Along with cephalosporins, prior quinolone use predisposed hospitalized patients to nosocomial CDAD. Quinolones should be used judiciously in acute-care hospitals, particularly in those where CDAD is endemic.

Nosocomial transmission of imipenem-resistant Pseudomonas aeruginosa following bronchoscopy associated with improper connection to the Steris System 1 processor.

Abstract: Objective To assess nosocomial transmission of imipenem-resistant Pseudomonas aeruginosa (IRPA) following bronchoscopy during August through October 1998. Design Traditional and molecular epidemiological investigation of a case series. Setting University-affiliated community hospital. Patients 18 patients with IRPA bronchial-wash isolates. Interventions We reviewed clinical data, performed environmental cultures and molecular analysis of all IRPA isolates, and observed disinfection of bronchoscopes. Results Of 18 patients who had IRPA isolated from bronchoscopic or postbronchoscopic specimens, 13 underwent bronchoscopy for possible malignancy or undiagnosed pulmonary infiltrates. Following bronchoscopy, 3 patients continued to have IRPA isolated from sputum and demonstrated clinical evidence of infection requiring specific antimicrobial therapy. The remaining 15 patients had no further IRPA isolated and remained clinically well 3 months following bronchoscopy. Pulsed-field gel electrophoresis revealed that all strains except one were >95% related. STERIS SYSTEM 1 had been implemented in July 1998 as an automatic endoscope reprocessor (AER) for all endoscopes and bronchoscopes. Inspection of bronchoscope sterilization cycles revealed incorrect connectors joining the bronchoscope suction channel to the STERIS SYSTEM 1 processor, obstructing peracetic acid flow through the bronchoscope lumen. No malfunction warning was received, and spore strips remained negative. Conclusions The similarity of diverse connectors and limited training by the manufacturer regarding AER for bronchoscopes were the two factors responsible for the outbreak. Appropriate connections were implemented, and there was no further bronchoscope contamination. We suggest active surveillance of all bronchoscopy specimen cultures, standardization of connectors of various scopes and automated processors, and systematic education of staff by manufacturers with periodic on-site observation.

Isolation in Brazil of nosocomial Staphylococcus aureus with reduced susceptibility to vancomycin.

Abstract: Objective:To evaluate the possible presence of vancomycin-resistant Staphylococcus aureus (VRSA) in a Brazilian hospital.Design:Epidemiological and laboratory investigation of nosocomial VRSAMethods:140 methicillin-resistant S aureus strains isolated between November 1998 and October 1999 were screened for susceptibility to vancomycin. The screening was carried out by using brain-heart infusion agar (BHIA) supplemented with 4, 6, and 8 μg/mL of vancomycin. The minimum inhibitory concentration (MIC) determination was carried out as standardized by the National Committee for Clinical Laboratory Standards using the broth macrodilution, agar-plate dilution, and E-test methods.Patients:Hospitalized patients exposed to vancomycin.Results:5 of the 140 isolates had a vancomycin MIC of 8 μg/mL by broth macrodilution, agar plate dilution, and E-test methods. Four VRSA strains were isolated from patients in a burn unit who had been treated with vancomycin for more than 30 days, and one from an orthopedic unit patient who had received vancomycin treatment for 7 days. Pulsed-field gel electrophoresis characterized four of the VRSA strains as belonging to the Brazilian endemic clone. All five strains were negative for vanA, vanB, and vanC genes by polymerase chain reaction. Transmission electron microscopy of the five strains revealed significantly thickened cell walls. One patient died due to infection caused by the VRSA strain.Conclusions:This is the first report of isolation of VRSA in Brazil and the first report of isolation of multiple VRSA strains from one facility over a relatively short period of time. This alerts us to the possibility that VRSA may be capable of nosocomial transfer if adequate hospital infection control measures are not taken.

Risk of exposure to bloodborne infection for Italian healthcare workers, by job category and work area. Studio Italiano Rischio Occupazionale da HIV Group.

Abstract: OBJECTIVE: To analyze the rate of occupational exposure prevalence of sharps in the working unit influence the risk to to blood and body fluids from all sources and specifically from housekeepers. The highest combined HIV exposure rates were human immunodeficiency virus (HIV)-infected sources among observed among nurses (7.8%) and physicians (1.9%) working in hospital workers, by job category and work area, infectious disease units. The highest rates of high-risk percutaDESIGN: Multicenter prospective study. Occupational neous exposures per 100 FTE were again observed in nurses exposure data (numerator) and full-time equivalents ([FTEs] regardless of work area, but this risk was higher in medical areas denominator) were collected over a 5-year period (1994-1998) and than in surgery (odds ratio, 2.1; 95% confidence interval, 1.9-2.5; analyzed. P<.0001). SETTING: 18 Italian urban acute-care hospitals with infec- CONCLUSION: Exposure risk is related to job tasks, as tious disease units, well as to the type and complexity of care provided in different RESULTS: A total of 10,988 percutaneous and 3,361 muco- areas, whereas HIV exposure risk mainly relates to the prevalence cutaneous exposures were reported. The highest rate of percuta- of HIV-infected patients in a specific area. The number of accident-neous exposure per 100 FTEs was observed among general prone procedures, especially those involving the use of hollow-surgery (11%) and general medicine (10.6%) nurses, the lowest bore needles, performed by job category influence the rate of among infectious diseases (1.1%) and laboratory (1%) physicians, exposure with high risk of infection. Job- and area-specific expoThe highest rates of mucocutaneous exposure were observed sure rates permit monitoring of the effectiveness of targeted interamong midwives (5.3%) and dialysis nurses (4.7%), the lowest ventions and control measures over time (Infect Control Hosp among pathologists (0%). Inadequate sharps disposal and the Epidemiol 2001;22:206-210).

Optimal frequency of changing intravenous administration sets: is it safe to prolong use beyond 72 hours?

Abstract: Objective: To determine the safety and cost-effectiveness of replacing the intravenous (TV) tubing sets in hospitalized patients at 4- to 7-day intervals instead of every 72 hours. Design: Prospective, randomized study of infusion-related contamination associated with changing IV tubing sets within 3 days versus within 4 to 7 days of placement. Setting: A tertiary university cancer center. Patients and Methods: Cancer patients requiring IV infusion therapy were randomized to have the IV tubing sets replaced within 3 days (280 patients) or within 4 to 7 days of placement (232 patients). Demographic, microbiological, and infusion-related data were collected for all participants. The main outcome measures were infusion- or catheter-related contamination or colonization of IV tubing, determined by quantitative cultures of the infusate, and infusion- or catheter-related bloodstream infection (BSI), determined by quantitative culture of the infusate in association with blood cultures in febrile patients. Results: The two groups were comparable in terms of patient and catheter characteristics and the agents given through the IV tubing. Intent-to-treat analysis demonstrated a higher level of tubing colonization in the 4- to 7-day group versus the 3-day group (median, 145 vs 50 colony-forming units; P=.02). In addition, there were three episodes of possible infusion-related BSIs, all of which occurred in the 4- to 7-day group (P=.09). However, when the 84 patients who received total parenteral nutrition, blood transfusions, or interleukin-2 through the IV tubing were excluded, the two groups had a comparable rate of colonization (0.4% vs 0.5%), with no catheter- or infusion-related BSIs in either group. Conclusion: In patients at low risk for infection from infusion- or catheter-related infection who are not receiving total parenteral nutrition, blood transfusions, or interleukin-2, delaying the replacement of IV tubing up to 7 days may be safe, as well as cost-effective.

Factors Associated With Postoperative Infection

Abstract: Objective:We have developed and analyzed a large surgical prophylaxis database and now report the factors significantly associated with early infection, readmission due to infection, and death within 28 days of surgery. This study is intended to be a stepping-stone for further studies using our clinical database.Design and Setting:A computerized database of 9,016 surgical patients from a 400-bed community hospital was examined. Multivariate logistic regression and tree-based modeling were used to identify factors associated with the outcomes. Factors considered included surgical procedure, prophylactic antibiotic, age, gender, serum creatinine, and albumin.Results:12.6% had an early infection, 2.5% were read-mitted due to infection, and 2.5% died within 28 days. Most combination prophylactic antibiotics were associated with an increased probability of an early infection. Decreased albumin and increased age were associated with an increased probability of an early infection. Tracheostomy and amputations were associated with an increased probability of an early infection, whereas gallbladder and orthopedic procedures involving the arm were associated with a decreased probability. Factors associated with readmission due to infection included dialysis shunt, vascular repair, and an early infection. Factors associated with increased probability of death within 28 days included age, albumin, serum creatinine, and an early infection. Gallbladder procedures and obstetric-gynecologic procedures were associated with a decreased probability of death within 28 days.Discussion:Older patients and those with a decreased albumin were most likely to have an early infection. To the extent that an early infection was a significant risk factor for readmission due to infection, the impact of age and albumin on the probability of readmission due to infection is demonstrated by their effects on early infections. Interestingly, albumin and age were significantly associated with death within 28 days, in addition to early infection, showing the predictive association between these factors and early death.

Lessons from outbreaks associated with bronchoscopy.

Abstract: Bronchoscopy is currently the most commonly employed invasive procedure in the practice of pulmonary medicine.1 An estimated 497,000 bronchoscopy procedures were performed in the United States in 1996.2 Current and new applications include bronchoscopic ultrasound, laser therapy, brachytherapy, electrocautery, cryotherapy, placement of airway stents, and balloon dilatation to relieve airway obstruction caused by airway lesions.3 Flexible endoscopes also are widely used in other medical disciplines. For example, more than 10,000,000 gastrointestinal endoscopies are performed each year.4 Endoscopes represent the medical devices most commonly linked to nosocomial outbreaks and pseudooutbreaks.5 Flexible endoscopes present a challenge for low-temperature sterilization or high-level disinfection, because they have long narrow lumens, cross-connections, mated surfaces, sharp angles, springs and valves, occluded dead ends, absorbent material, and rough or pitted surfaces.6,7 Failure to eradicate contamination that occurred during use may lead to person-to-person transmission of pathogens (eg, Mycobacterium tuberculosis); failure to prevent contamination during disinfection or storage may lead to outbreaks or pseudo-outbreaks from environmental microbes (eg, nontuberculous mycobacteria, or Rhodotorula rubra). In this issue, Sorin and colleagues8 describe the nosocomial transmission of an imipenemresistant strain of Pseudomonas aeruginosa, and Kressel and Kidd9 describe a pseudo-outbreak involving organisms relatively resistant to glutaraldehyde (ie, Mycobacterium chelonae and Methylobacterium mesophilicum) associated with the use of contaminated bronchoscopes. Prevention of endoscope-related infections requires strict adherence to current guidelines for cleaning and disinfection. Guidelines for disinfection of flexible endoscopes, including bronchoscopes, have been published by the Association for Professionals in Infection Control and Epidemiology, Inc.10,11 To date, nosocomial outbreaks have not been reported in which all current recommendations were followed scrupulously. These guidelines are based on sound scientific principles generated from several sources of data: first, studies on the natural bioburden of endoscopes and efficacy of cleaning; second, studies on the in vitro efficacy of recommended high-level disinfectants and low-temperature sterilization methods; third, studies of disinfection of simulated endoscopes or experimentally inoculated endoscopes; fourth, studies of the effectiveness of current high-level disinfection and sterilization methods in actual practice; and finally, lessons learned from outbreaks and pseudo-outbreaks involving endoscopes. Only limited data are available on the bioburden present on bronchoscopes following use. Alfa and Sitter reported the average load on bronchoscopes before cleaning was 6.4 104 colony-forming units (CFUs)/mL, with streptococci and normal upper respiratory flora being reported.12 The bioburden on used gastrointestinal endoscopes is higher, ranging from 106 to 107 CFUs for upper gastrointestinal endoscopes and 108 to 1010 CFUs for colonoscopes.13 Cleaning has been demonstrated to reduce the bioburden on endoscopes in most studies by more than 4 logs.13 Cleaning also removes organic and inorganic debris that may compromise the disinfection and sterilization process. For example, Alfa and colleagues tested several low-temperature sterilization methods (ie, ethylene

Costs and savings associated with infection control measures that reduced transmission of vancomycin-resistant enterococci in an endemic setting.

Abstract: Objective To determine the costs and savings of a 15-component infection control program that reduced transmission of vancomycin-resistant enterococci (VRE) in an endemic setting. Design Evaluation of costs and savings, using historical control data. Setting Adult oncology unit of a 650-bed hospital. Participants Patients with leukemia, lymphoma, and solid tumors, excluding bone marrow transplant recipients. Methods Costs and savings with estimated ranges were calculated. Excess length of stay (LOS) associated with VRE bloodstream infection (BSI) was determined by matching VRE BSI patients with VRE-negative patients by oncology diagnosis. Differences in LOS between the matched groups were evaluated using a mixed-effect analysis of variance linear-regression model. Results The cost of enhanced infection control strategies for 1 year was $116,515. VRE BSI was associated with an increased LOS of 13.7 days. The savings associated with fewer VRE BSI ($123,081), fewer patients with VRE colonization ($2,755), and reductions in antimicrobial use ($179,997) totaled $305,833. Estimated ranges of costs and savings for enhanced infection control strategies were $97,939 to $148,883 for costs and $271,531 to $421,461 for savings. Conclusion The net savings due to enhanced infection control strategies for 1 year was $189,318. Estimates suggest that these strategies would be cost-beneficial for hospital units where the number of patients with VRE BSI is at least six to nine patients per year or if the savings from fewer VRE BSI patients in combination with decreased antimicrobial use equalled $100,000 to $150,000 per year.

Pseudo-outbreak of Mycobacterium chelonae and Methylobacterium mesophilicum caused by contamination of an automated endoscopy washer.

Abstract: Objective:To evaluate an unusual number of rapidly growing acid-fast bacilli, later identified as Mycobacterium chelonae, and pink bacteria, later identified as Methylo-bacterium mesophilicum, from fungal cultures obtained by bronchoscopy.Design:Outbreak investigation.Setting:An academic medical center performing approximately 500 bronchoscopies and 4,000 gastrointestinal endoscopies in 1998.Patients:Patients undergoing bronchoscopy July 21 to October 2, 1998.Methods:The infection control department reviewed patient charts and bronchoscopy logs; obtained cultures of source water, faucets, washers, unopened glutaraldehyde, glutaraldehyde from the washers, and endoscopes; observed endoscope and bronchoscope cleaning and disinfecting procedures; reviewed glutaraldehyde monitoring records; and sent M chelonae isolates for DNA fingerprinting.Results:M chelonae, M mesophilicum, gram-negative bacteria, and various molds grew from endoscopes, automated washers, and glutaraldehyde from the washers but not from unopened glutaraldehyde. The endoscopy unit regularly monitored the pH of glutaraldehyde, and the logs contained no deficiencies. The above sources remained positive for the same organisms after a glutaraldehyde cleaning cycle of the automated washers. DNA fingerprinting of the M chelonae revealed that they were clonally related.Conclusions:The automated washers were contaminated with a biofilm that rendered them resistant to decontamination. The washers then contaminated the endoscopes and bronchoscopes they were used to disinfect. Our institution purchased new endoscopes and a new paracetic acid sterilization system.

Molecular epidemiology of an outbreak of Serratia marcescens in a neonatal intensive care unit.

Abstract: Objective: To investigate and control a biphasic outbreak of Serratia marcescens in a neonatal intensive care unit (NICU). Design: Epidemiological and laboratory investigation of the outbreak. Setting: The NICU of the 1,470-bed teaching hospital of the University “Federico II,” Naples, Italy. Patients: The outbreak involved 56 cases of colonization by S marcescens over a 15-month period, with two epidemic peaks of 6 and 3 months, respectively. Fourteen (25%) of the 56 colonized infants developed clinical infections, 50% of which were major (sepsis, meningitis, or pneumonia). Methods: Epidemiological and microbiological investigations, analysis of macrorestriction pattern of genomic DNA through pulsed-field gel electrophoresis (PFGE) of clinical and environmental isolates, and institution of infection control measures. Results: Analysis of macrorestriction patterns of genomic DNA by PFGE demonstrated that the vast majority of S marcescens isolates, including three environmental strains isolated from two handwashing disinfectants and the hands of a nurse, were of the same clonal type. The successful control of the outbreak was achieved through cohorting of noncolonized infants, isolation of S marcescens-infected and -colonized infants, and an intense educational program that emphasized the need for adherence to glove use and handwashing policies. The NICU remained open to new admissions. Conclusions: Outbreaks caused by S marcescens are very difficult to eradicate. An infection control program that includes molecular typing of microorganisms and the proper dissemination among staff members of the typing results is likely to be very effective in reducing NICU-acquired infections and in controlling outbreaks caused by S marcescens, as well as other multiresistant bacteria.

Hepatitis C in a Ward for Cystic Fibrosis and Diabetic Patients Possible Transmission by Spring-Loaded Finger-Stick Devices for Self-Monitoring of Capillary Blood Glucose

Abstract: OBJECTIVE: To identify the routes of transmission in a nosocomial outbreak of hepatitis C virus (HCV) infection. DESIGN: Epidemiological investigation, including screening for HCV of hospitalized patients, and a retrospective cohort study, review of hygiene and medical practices, and molecular comparison of HCV isolates. SETTING: A specialized care unit for cystic fibrosis (CF) and diabetic patients at an acute-care facility in the south of France. RESULTS: Of the 57 CF patients (age in 1995: 2-28 years), 38 (66.7%) were tested and 22 (57.9%) were anti-HCV positive. Eight (50%) of 16 patients with anti-HCV antibody tested by polymerase chain reaction were viremic. No patients had received blood products or had any history of intravenous drug use. All 18 (100%) patients with CF who had ever undergone self-monitoring of capillary blood glucose in the unit were anti-HCV positive, compared to 4 (20%) of 20 who had not (relative risk, 5.0; 95% confidence interval, 2.1-12.0). Seventy (39.5%) of the patients with diabetes were screened for anti-HCV; 12 (18.8%) tested positive, with 3 (25%) positive for HCV-RNA. Patients with diabetes had routine capillary blood glucose monitoring while hospitalized and shared with CF patients the same spring-triggered devices for capillary blood glucose monitoring. The disposable platform of the devices was not changed between patient use. All HCV isolates belonged to the type 1, subtype b, and phylogenetic analysis showed a close homology by sequencing of NS5b and E2/HVR regions. CONCLUSION: As reported earlier for the hepatitis B virus, shared spring-triggered devices for capillary blood glucose monitoring by finger puncture may transmit HCV. Strict application of Standard Precautions procedures is warranted in any healthcare setting.

An outbreak of scabies in a teaching hospital: lessons learned.

Abstract: Objective To investigate an outbreak of scabies in an inner-city teaching hospital, identify pathways of transmission, institute effective control measures to end the outbreak, and prevent future occurrences. Design Outbreak investigation, case-control study, and chart review. Setting Large tertiary acute-care hospital. Results A patient with unrecognized Norwegian (crusted) scabies was admitted to the acquired immunodeficiency syndrome (AIDS) service of a 940-bed acute-care hospital. Over 4 months, 773 healthcare workers (HCWs) and 204 patients were exposed to scabies. Of the exposed HCWs, 147 (19%) worked on the AIDS service. Risk factors for being infested with scabies among HCWs included working on the AIDS service (odds ratio [OR], 5.3; 95% confidence interval [CI95], 2.17-13.15) and being a nurse, physical therapist, or HCW with extensive physical contact with infected patients (OR, 4.5; CI95, 1.26-17.45). Aggressive infection control precautions beyond Centers for Disease Control and Prevention barrier and isolation recommendations were instituted, including the following: (1) early identification of infected patients; (2) prophylactic treatment with topical applications for all exposed HCWs; (3) use of two treatments 1 week apart for all cases of Norwegian scabies; (4) maintaining isolation for 8 days and barrier precautions for 24 hours after completing second treatment for a diagnosis of Norwegian scabies; and (5) oral ivermectin for treatment of patients who failed conventional therapy. Conclusions HCWs with the most patient contact are at highest risk of acquiring scabies. Because HCWs who used traditionally accepted barriers while caring for patients with Norwegian scabies continued to develop scabies, we found additional measures were required in the acute-care hospital. HCWs with skin exposure to patients with scabies should receive prophylactic treatment. We recommend (1) using heightened barrier precautions for care of patients with scabies and (2) extending the isolation period for 8 days or 24 hours after the second treatment with a scabicide for those patients with Norwegian scabies. Oral ivermectin was well tolerated for treating patients and HCWs who failed conventional treatment. Finally, we developed a surveillance system that provides a "barometric measure" of the infection rate in the community. If scabies increases in the community, a tiered triage system is activated to protect against transmission among HCWs or hospital patients.

Persistence of immunity to varicella-zoster virus after vaccination of healthcare workers.

Abstract: OBJECTIVE: Varicella-zoster virus (VZV) vaccine is recommended to protect susceptible healthcare workers (HCWs) from serious disease and to prevent nosocomial spread of VZV. We evaluated clinical outcomes and serological responses in HCWs after immunization with live attenuated VZV vaccine. DESIGN: Vaccinees were immunized from 1979 to 1998 during VZV vaccine trials, as well as after licensure, and followed prospectively for 1 month to 20.6 (mean 4.6) years after vaccination. Sera were tested by fluorescent antibody to membrane antigen (FAMA), latex agglutination (LA), and enzyme-linked immunoassay (EIA) to detect VZV-specific antibodies. STUDY PARTICIPANTS: The median age of the 120 HCWs was 26 years; 51 (42%) were males. INTERVENTIONS: Ninety eight (82%) of these study subjects received vaccine prepared by Merck and 22 (18%) by SmithKline Beecham; 25, 81, and 14 vaccinees received one dose, two doses, and three doses, respectively. RESULTS: The crude attack rate was 10%; 12 of 120 HCWs developed chickenpox 6 months to 8.4 years after vaccination. The attack rates following household and hospital exposures were 18% (4/22) and 8% (6/72), respectively. All resulting illness was mild to moderate (mean 40 vesicles). Seroconversion after vaccination was documented by FAMA in 96% of HCWs, although 31% lost detectable antibodies. Compared with FAMA, LA and EIA were 82% and 74% sensitive and 94% and 89% specific, respectively. CONCLUSIONS: The VZV vaccine effectively protected HCWs from varicella, particularly from serious disease. Currently available serological tests are not optimal, and improved assays are needed.