Rates of Stenotrophomonas maltophilia colonization and infection in relation to antibiotic cycling protocols.

This study evaluated whether antibiotic cycling programmes using broad-spectrum agents including carbapenems were associated with increased rates of colonization or infection by Stenotrophomonas maltophilia. Retrospective analyses of colonization or infection by S. maltophilia from 1992 to 2002 were conducted using University of Virginia Hospital clinical microbiology records of patients with any culture positive for S. maltophilia and hospital epidemiology records of nosocomial S. maltophilia infections. Incidence rates were calculated and compared for cycling and non-cycling periods. No significant differences were found in incidence rates of S. maltophilia isolates between cycling and non-cycling periods, but there was a significant secular increase in the hospital-wide rate of infections caused by S. maltophilia (P=0.01728). Antibiotic cycling protocols were not associated with a significantly increased rate of colonization of S. maltophilia as determined by the frequency of patients having at least one positive routine clinical culture in this hospital.

Effect of a vancomycin restriction policy on ordering practices during an outbreak of vancomycin-resistant Enterococcus faecium.

BACKGROUND: With the development of nosocomial pathogens that are resistant to multiple antimicrobial agents, reasonable restriction of antibiotic use has become a priority. METHODS: During an outbreak of vancomycin-resistant enterococcal infections, an audit of vancomycin hydrochloride use was conducted during October 3 through 21, 1994, and January 24 through February 2, 1995. During these periods, all orders for vancomycin were reviewed by clinical pharmacists. Use was classified as either appropriate or inappropriate based on recommendations by the Hospital Infection Control Practice Advisory Committee (HICPAC) of the Centers for Disease Control and Prevention, Atlanta, Ga. A policy restricting the use of vancomycin was adopted in November 1994. RESULTS: During the first audit in October 1994, 61% of vancomycin orders were considered inappropriate according to HICPAC criteria. At the time of this audit, the first cases of an outbreak of nosocomial vancomycin-resistant Enterococcus faecium had been detected. The follow-up audit showed that 30% of vancomycin orders were inappropriate by HICPAC criteria (P < .001). Overall use of vancomycin decreased by 50% and remained at this lower level for the following year. CONCLUSION: The institution of a vancomycin restriction policy was associated with a reduction of both inappropriate drug orders and total use.

A randomized crossover study of silver-coated urinary catheters in hospitalized patients.

BACKGROUND: Urinary tract infections (UTIs) account for 30% to 40% of nosocomial infections resulting in morbidity, mortality, and increased length of hospital stay. OBJECTIVE: To assess the efficacy of a silver-alloy, hydrogel-coated latex urinary catheter for the prevention of nosocomial catheter-associated UTIs. METHODS: A 12-month randomized crossover trial compared rates of nosocomial catheter-associated UTI in patients with silver-coated and uncoated catheters. A cost analysis was conducted. RESULTS: There were 343 infections among 27,878 patients (1.23 infections per 100 patients) during 114,368 patient-days (3.00 infections per 1000 patient-days). The relative risk of infection per 1000 patient-days was 0.79 (95% confidence interval, 0.63-0.99; P =.04) for study wards randomized to silver-coated catheters compared with those randomized to uncoated catheters. Infections occurred in 291 of 11,032 catheters used on study units (2.64 infections per 100 catheters). The relative risk of infection per 100 silver-coated catheters used on study wards compared with uncoated catheters was 0.68 (95% confidence interval, 0.54-0.86; P =.001). Fourteen catheter-associated UTIs (4.1%) were complicated by secondary bloodstream infection. One death appeared related to the secondary infection. Estimated hospital cost savings with the use of the silver-coated catheters ranged from $14,456 to $573,293. CONCLUSIONS: The risk of infection declined by 21% among study wards randomized to silver-coated catheters and by 32% among patients in whom silver-coated catheters were used on the wards. Use of the more expensive silver-coated catheter appeared to offer cost savings by preventing excess hospital costs from nosocomial UTI associated with catheter use. Arch Intern Med. 2000;160:3294-3298.

Preventing pneumococcal bacteremia in patients at risk. Results of a matched case-control study.

BACKGROUND: Three randomized controlled trials of the effectiveness of pneumococcal vaccine in elderly and chronically ill adults in the United States have failed to show significant protective efficacy during 44,213 person-years of follow-up. Case-control studies have greater statistical power to detect significant prevention of rare diseases such as pneumococcal bacteremia, but they also have a greater susceptibility to bias, necessitating consistent results from multiple studies. Three case-control studies at two different universities have shown prevention of systemic infection, but another study found no benefit. METHODS: Patients with pneumococcal bacteremia who were at least 2 years old and had chronic illness indicating the need for pneumococcal vaccine, or who were at least 65 years old were compared with matched control subjects for frequency of prior vaccination. Matching variables included date of admission, age, sex, race, type and duration of chronic illness serving as the major vaccine indication, number of vaccine indications and number of medical hospitalizations since licensure of the pneumococcal vaccine in 1978, and type of primary medical care. RESULTS: Pneumococcal vaccination was documented in the records of six (7%) of 85 cases and 26 (17%) of 152 control subjects, suggesting 81% efficacy in conditional logistical regression analysis (95% confidence interval, 34% to 94%, P = .008). CONCLUSIONS: Four case-control studies at three universities have now demonstrated significant protective efficacy of pneumococcal vaccine for preventing pneumococcal bacteremia. The development of antibiotic-resistant Streptococcus pneumoniae indicates an urgent need for an increased rate of vaccination among high-risk patients and for the development of more immunogenic conjugate vaccines that may enhance efficacy among elderly and immunocompromised patients as well as infants.

Can antibiotic-resistant nosocomial infections be controlled?

Three decades ago infection-control programmes were created to control antibiotic-resistant nosocomial infections, but numbers of these infections have continued to increase, leading many to question whether control is feasible. Meticillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci were major problems during the 1990s. Many hospitals have tried antibiotic control but with limited efficacy against these pathogens. Studies of antibiotic restriction, substitution, and cycling have been promising, but more definitive data are needed. Increased compliance with hand hygiene would help but is unlikely to control this problem alone as a result of frequent contamination of other surfaces even when hands are cleansed and high transmission rates when hand hygiene is neglected. For 17 years, the Centers for Disease Control and Prevention have recommended contact precautions for preventing nosocomial spread of important antibiotic-resistant pathogens. Many studies confirm that this approach works when sufficient active-surveillance cultures are undertaken to detect the reservoir for spread. However, most healthcare facilities have not yet tried this approach.

Reasons for noncompliance with infection control guidelines.

Concern frequently is voiced about individuals not complying with guidelines intended to prevent spread of antibiotic-resistant pathogens from patient to patient, but institutional decisions to ignore Centers for Disease Control and Prevention guidelines recommending detection and isolation of colonized patients also have contributed greatly to the increasing rate of infections due to these pathogens. This is so because colonized patients are the main reservoir for spread, and barrier precautions prevent spread much more effectively than Standard Precautions. Providing effective leadership and changing this culture of noncompliance must begin with the infection control team believing that spread is both important and preventable.

Morbidity and mortality associated with multiple episodes of nosocomial bloodstream infection: a cohort study.

A retrospective cohort study of patients with multiple nosocomial bloodstream infections (BSIs) compared with patients suffering only one BSI was conducted to assess morbidity and mortality. Three hundred forty-one patients with BSIs were identified, including 33 with multiple BSIs (9.7%). No significant differences existed between patients experiencing one BSI compared to those experiencing multiple BSIs in age, sex, race, severity of underlying disease, hypothermia, hypoxemia, oliguria, metabolic acidosis, or hypotension. Sixteen of 33 (49%) with multiple BSIs died compared with 124 of 308 (40%) with only one BSI (P = 0.36), leading to a relative risk of 1.23 for death and an attributable mortality of 9% in those with multiple BSIs.

Diagnostic tests: distinguishing good tests from bad and even ugly ones.

This article focuses on the selection and interpretation of diagnostic tests, emphasizing the importance of understanding how their mathematical parameters affect the information they provide in various settings. The utility and limitations of sensitivity, specificity, predictive value, and receiver operating characteristic (ROC) curves are discussed using catheter-related bloodstream infections as an example. ROC curves have been used for selecting optimal cutoff values for a positive result and for selecting among several alternative diagnostic tests. For example, 16 different tests have been proposed for diagnosis of catheter-related bloodstream infection; ROC analysis provides an effective way to determine which test offers the best overall performance.

Primary cytomegalovirus infection in pediatric nurses: a meta-analysis.

A meta-analysis of six controlled studies was performed to evaluate the risk of cytomegalovirus (CMV) infection among pediatric nurses. The pooled risk ratio for CMV infection in pediatric nurses using cumulative incidence data was statistically significant (risk ratio [RR] 2.7; 95% confidence interval [CI] 1.33 - 5.52), but person-year analysis taking account of follow-up periods demonstrated a trend toward increased risk that failed to reach statistical significance (RR 1.8; 95% CI 0.88 - 3.55). Despite pooling, there was low statistical power for comparing person-year rates. The studies included in this analysis failed to provide data on several potential confounding variables. We conclude that studies published prior to the widespread adoption of universal precautions suggest that pediatric nurses may have been at increased risk for CMV infection due to occupational exposure, but inadequate design and sample size of the studies prevent a definitive conclusion. Well-designed, controlled studies are still needed to define the occupational risk of CMV infection.

A randomized crossover study of disposable thermometers for prevention of Clostridium difficile and other nosocomial infections.

OBJECTIVE: To test the hypothesis that use of disposable thermometers would result in lower rates of nosocomial Clostridium difficile diarrhea and of total nosocomial infections, compared with electronic thermometers. DESIGN: Prospective randomized crossover trial. SETTING: A 700-bed university hospital providing primary and tertiary care. PATIENTS: All patients admitted to a group of 20 inpatient nursing units. INTERVENTIONS: 20 nursing units were randomized into two groups. One group randomly was assigned exclusive use of single-use disposable thermometers for patient temperature measurement, and the other group was assigned exclusive use of electronic thermometers. After 6 months, the assignments were reversed. MAIN OUTCOME MEASURES: Rates of C difficile infections, total nosocomial diarrheal episodes, and total nosocomial infections were prospectively followed in each study unit over 11 months. RESULTS: 26,350 patients were admitted to the study units and hospitalized for 120,529 patient days. There were 947 nosocomial infections (7.86 per 1,000 patient days). Nosocomial C difficile-associated diarrhea defined by positivity to both toxin B (titer > or = 1:10) and toxin A was detected in 32 patients (3.4% of all nosocomial infections). A significantly lower rate of nosocomial C difficile-associated diarrhea was observed with disposable thermometer use (0.16 per 1,000 patient days) compared with electronic thermometer use (0.37 per 1,000 patient days, relative risk [RR] = 0.44; 95% confidence interval [CI95], 0.21-0.93, P = .026). There was no difference in overall rates of nosocomial infection between the disposable and electronic groups (8.03 and 7.68 infections per 1,000 patient days, respectively; RR, 1.04; CI95, 0.92-1.19; P = .52) or in the overall rate of nosocomial diarrhea (3.34 and 3.40 per 1,000 patient days, respectively; RR, .98; CI95, 0.81-1.19; P = .87). CONCLUSIONS: The incidence of nosocomial C difficile diarrhea was reduced significantly by using single-use, disposable thermometers as compared with electronic thermometers, but there was no effect on either the overall rate of nosocomial diarrhea or the rate of total nosocomial infections.

Frequency of percutaneous injuries requiring postexposure prophylaxis for occupational exposure to human immunodeficiency virus.

New recommendations regarding prophylaxis of healthcare workers exposed to human immunodeficiency virus (HIV) prompted us to examine the frequency and nature of percutaneous injuries at this hospital. Four previously defined risk factors for transmission of HIV were evaluated. Between 1993 and 1995, 1,070 percutaneous injuries were reported, including 11 in which the source patient had acquired immunodeficiency syndrome (AIDS). Five of these injuries involved at least one risk factor for transmission. No source patient was found to have AIDS as a result of testing following exposure. We conclude that high-risk injuries are infrequent and that postexposure prophylaxis will not increase costs greatly at this medical center.

Selective surveillance for nosocomial infections in a Brazilian hospital.

OBJECTIVE: To devise a system for surveying the frequency of nosocomial infections in a tertiary care hospital in a developing country. DESIGN: Prospective selective surveillance by nurses of the charts of patients at high risk for nosocomial infections, as identified by a form completed by resident physicians. The sensitivity, specificity, and predictive value of this method of selective surveillance were compared with those for total prospective chart review by two infectious disease specialists. SETTING: A university hospital in northeastern Brazil. PATIENTS: All patients hospitalized for more than 72 hours with an identified risk factor for nosocomial infection. RESULTS: The ratio of nosocomial infections to 100 discharges was 13.4 and the incidence density was 11.2/1,000 patient days. The surveillance method demonstrated a sensitivity of 74% and a specificity of 99.7%. Positive predictive value was 93%, negative predictive value was 99%, and overall accuracy was 98%. CONCLUSIONS: This method of selective surveillance for nosocomial infections based on risk factors identified by physicians demonstrated excellent predictive value and overall accuracy and may be of use to other hospitals that lack a nursing care plan book such as the Kardex. The relative frequency of nosocomial infections significantly exceeded the rates reported from hospitals in developed countries.

An outbreak of needlestick injuries in hospital employees due to needles piercing infectious waste containers.

OBJECTIVES: To investigate the cause of an outbreak of needlestick injuries (NSIs) in hospital employees. SETTING: A 700-bed university hospital. DESIGN: Outbreak investigation, laboratory evaluation of a medical waste disposal device, cost analysis. METHODS: Employee health department records were reviewed of workers suffering sticks from needles piercing fiberboard-contaminated material containers (CMCs). A laboratory evaluation of needle-puncture resistance properties of the CMCs was performed using a testing apparatus. The cost of a hospital waste disposal program using fiberboard CMCs was compared with the cost of a program using rigid plastic (polypropylene) boxes. RESULTS: During 40 months of surveillance in 1986 and from 1989 to 1991, only one NSI had occurred from a needle piercing a CMC. During 9 months in 1993, 13 NSIs occurred due to needles piercing CMCs (P < .001). No clinical illness resulted from the NSIs. The outbreak was halted by a temporary change to plastic (polypropylene) boxes for sharps disposal ($4.92 to $23.33/cu ft) until receipt of a box with a newly designed solid fiberboard liner ($1.25/cu ft). CMC liners used during the epidemic had a mean needle puncture resistance of 527 g, as compared with 660 g for liners used before the outbreak (P < .001). The new solid fiberboard liner has a mean puncture resistance of 1,765 g. A program of waste disposal using fiberboard CMCs was found to cost approximately one-seventh the cost of a program using plastic boxes for disposal of infectious waste. CONCLUSION: A program for infectious waste disposal using fiberboard CMCs can be safe and cost-effective if appropriate standards for puncture resistance are met.

Control of methicillin-resistant Staphylococcus aureus at a university hospital: one decade later.

OBJECTIVE: To investigate the cause of increasing rates of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection at a university hospital. DESIGN: Review of data collected by prospective hospital wide surveillance regarding rates of nosocomial MRSA colonization and infection. SETTING: A 700-bed university hospital providing primary and tertiary care. PATIENTS: Patients admitted to the hospital between 1986 and 1993 who were found to be infected or colonized with MRSA. MAIN OUTCOME MEASUREMENT: Rates of MRSA infection and colonization. RESULTS: MRSA infection or colonization was identified in 399 patients (0.18%) admitted during the 8-year study. There was no correlation between the annual rates of MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) infections (P = .66). The frequency of both nosocomial and non-nosocomial cases increased significantly over the last 4 years of the study (P < .001 for trend). The ratio of patients who had acquired MRSA nosocomially to those admitted who already were infected or colonized decreased significantly during the study period (P = .002 for trend). There was a significant increase in the frequency of patients with MRSA being transferred from nursing homes and other chronic care facilities (P = .011). A cost-benefit analysis suggested that surveillance cultures of patients transferred from other healthcare facilities would save between $20,062 and $462,067 and prevent from 8 to 41 nosocomial infections. CONCLUSIONS: An increase in the incidence of nosocomial MRSA infection was associated with an increased frequency of transfer of colonized patients from nursing homes and other hospitals. The lack of correlation between rates of MRSA and MSSA infections suggested that MRSA infections significantly increased the overall rate of staphylococcal infection. Screening cultures of transfer patients from facilities with a high prevalence of MRSA may offer significant benefit by preventing nosocomial infections and reducing patient days spent in isolation.

Prevention of nosocomial influenza.

OBJECTIVE: To study compliance with preventive strategies at a university hospital during an outbreak of nosocomial influenza A during the winter of 1988, and the rates of vaccination of healthcare workers and of nosocomial influenza following changes in vaccine practices after the outbreak. DESIGN: Retrospective review of employee health, hospital epidemiology, hospital computing; and clinical microbiology records. SETTING: A university hospital. INTERVENTIONS: Unvaccinated personnel with exposure within the previous 72 hours to an unisolated case of influenza were offered influenza vaccine and 14 days of amantadine hydrochloride prophylaxis. Personnel with exposure more than 72 hours before evaluation were offered vaccine. A mobile cart was introduced for vaccinating personnel after the 1988 outbreak. RESULTS: An outbreak of influenza with 10 nosocomial cases occurred in 1988. Only 4% of exposed employees had been vaccinated previously and 23% of exposed, unvaccinated employees agreed to take vaccine, amantadine, or both. A mobile-cart vaccination program was instituted, and annual vaccination rates steadily increased from 26.3% in 1989 to 1990 to 38% in 1993 to 1994 (P < .0001). The relative frequency of documented cases of influenza in employees with symptoms of influenza decreased significantly during this period (P = .025), but nosocomial influenza rates among patients did not change significantly. CONCLUSION: A mobile-cart influenza vaccination program was associated with a significant increase in compliance among healthcare workers, but a majority still remained unvaccinated. The rate of nosocomial influenza among patients was not reduced by the modest increase in the vaccination rate, but influenza rates remained acceptably low, perhaps due to respiratory isolation of patients and furlough of employees with influenza.

Disinfection of hospital rooms contaminated with vancomycin-resistant Enterococcus faecium.

Sixteen percent of hospital room surfaces remained colonized by vancomycin-resistant enterococci (VRE) after routine terminal disinfection. Disinfection with a new "bucket method" resulted in uniformly negative cultures. Conventional cleaning took an average of 2.8 disinfections to eradicate VRE from a hospital room, while only one cleaning was required with the bucket method.

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

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

Requirements for infrastructure and essential activities of infection control and epidemiology in hospitals: a consensus panel report. Society for Healthcare Epidemiology of America.

The scientific basis for claims of efficacy of nosocomial infection surveillance and control programs was established by the Study on the Efficacy of Nosocomial Infection Control project. Subsequent analyses have demonstrated nosocomial infection prevention and control programs to be not only clinically effective but also cost-effective. Although governmental and professional organizations have developed a wide variety of useful recommendations and guidelines for infection control, and apart from general guidance provided by the Joint Commission on Accreditation of Healthcare Organizations, there are surprisingly few recommendations on infrastructure and essential activities for infection control and epidemiology programs. In April 1996, the Society for Healthcare Epidemiology of America established a consensus panel to develop recommendations for optimal infrastructure and essential activities of infection control and epidemiology programs in hospitals. The following report represents the consensus panel's best assessment of needs for a healthy and effective hospital-based infection control and epidemiology program. The recommendations fall into eight categories: managing critical data and information; setting and recommending policies and procedures; compliance with regulations, guidelines, and accreditation requirements; employee health; direct intervention to prevent transmission of infectious diseases; education and training of healthcare workers; personnel resources; and nonpersonnel resources. The consensus panel used an evidence-based approach and categorized recommendations according to modifications of the scheme developed by the Clinical Affairs Committee of the Infectious Diseases Society of America and the Centers for Disease Control and Prevention's Hospital Infection Control Practices Advisory Committee.

Survey of patients' knowledge of nosocomial infections.

A survey of discharged patients revealed that 62% of respondents were aware of the risk of nosocomial infection before they received the survey. Of the respondents 12.4% said they had suffered from a nosocomial infection; 70% were concerned about their risk of acquiring a nosocomial infection in the future; 83% believed nosocomial infections were preventable; 69% said the risk of acquiring a nosocomial infection was never explained to them during hospitalization; and 62% were dissatisfied with the information that hospitals and the medical community provided concerning the risk of nosocomial infections. Fifty-seven percent were willing to pay an extra $7.14 mean per diem charge to enhance the hospital's infection control program if this payment would lower their risk of infection. This survey suggests that the subset of responding patients want to know more about the risk of nosocomial infections, and they are willing to pay for more resources to be channeled into effective infection control programs.

Central venous catheter practices: results of a survey.

BACKGROUND: The incidence of nosocomial bloodstream infections has increased twofold to threefold in the past decade, and central venous catheter infections account for about 90% of catheter-related nosocomial bloodstream infections. Many studies of risk factors for central venous catheter complications have been conducted, resulting in recommendations for preventive strategies, but few data are available regarding the frequency with which such strategies are employed in clinical practice. METHODS: A survey was conducted of persons attending a meeting of the National Association of Vascular Access Networks in New Orleans on September 25, 1992. The survey contained 15 questions related to central venous catheters regarding infection control measures, measures to maintain patency, and use of the catheter for obtaining blood specimens for diagnostic tests. RESULTS: Ninety-two persons from 24 states completed the questionnaire as representatives of 23 teaching hospitals, 21 nonteaching hospitals, and 48 home health agencies. Transparent dressings were used more frequently (88%) than cotton gauze (27%). Alcohol and povidone-iodine solutions were the most frequently used antiseptics. Antimicrobial ointment was used by fewer than half; of these 86% used povidone-iodine and 26% used polymyxin-neomycin-bacitracin. Heparin flushes were still being used by 97% to maintain patency. Most (82%) used central venous catheters to draw blood cultures; of these, 68% drew only qualitative cultures and 32% drew quantitative cultures in addition to or instead of qualitative cultures. CONCLUSIONS: Significant diversity of practice was documented among the health care organizations represented in this survey. Some of the practices documented in this survey have been associated with higher rates of bloodstream infection; this may partially explain the observed increase during the past decade in the incidence of nosocomial bloodstream infections.