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.

A pseudo-outbreak of nosocomial infections associated with the introduction of an antibiotic management programme.

An abrupt and persistent 30% increase in the rate of nosocomial infections was detected at a university teaching hospital after a prolonged period with a relatively constant nosocomial infection rate. Demographic data, risk factors for nosocomial infection, features of reported cases of nosocomial infection, and policy and procedure changes were evaluated for the periods of 1 January 1997 to 30 April 1998 (endemic period) and 1 May to 31 December 1998 (epidemic period). An extensive outbreak investigation revealed no evidence of a true outbreak of nosocomial infection. The apparent outbreak involved all four major body sites, began during the same month that an antibiotic management programme was started, involved the same adult medical and surgical units where antibiotics were being controlled, and occurred months before any significant change in antibiotic usage. A greater proportion of nosocomial infection during the epidemic period was reported by the nosocomial infection surveillance nurses, based on a treating physician's diagnosis rather than on specific clinical criteria. In an attempt to justify existing antibiotic prescribing practices after the implementation of an antibiotic management programme, clinicians altered the threshold at which they documented the presence of nosocomial infection. This change in documentation produced a large pseudo-outbreak of nosocomial infection.

Cost-effectiveness of active surveillance cultures and contact/droplet precautions for control of methicillin-resistant Staphylococcus aureus.

Some have reported that adopting Centers for Disease Control and Prevention guidelines requiring contact precautions for methicillin-resistant Staphylococcus aureus (MRSA) had no impact on rates of nosocomial spread or infection, and may therefore waste money. The objective of the present study was to evaluate the cost-effectiveness of active surveillance cultures and barrier precautions for controlling MRSA. Estimated costs of surveillance cultures and isolation measures used during an MRSA outbreak at this hospital were compared with the estimated attributable excess costs of methicillin resistance (i.e., the difference between MRSA and methicillin-sensitive S. aureus costs) for bacteraemias occurring during an MRSA outbreak not promptly controlled at another hospital. The study was set in the neonatal intensive care units of two tertiary care hospitals. Estimated costs of controlling the 10.5-month outbreak in this neonatal intensive care unit that resulted in 18 colonized and four infected infants ranged from $48 617 to $68 637. The estimated attributable excess cost of 75 MRSA bacteraemias in a second neonatal intensive care unit outbreak that resulted in 14 deaths and lasted 51 months was $1 306 600. Weekly active surveillance cultures and isolation of patients with MRSA halted an outbreak at this hospital, and cost 19- to 27-fold less than the attributable costs of MRSA bacteraemias in another outbreak that was not promptly controlled. The costs of infections at other body sites and the human cost of deaths from infection were not estimated but would further help to justify the cost of identifying colonized patients and implementing effective preventive measures.

Preventing vascular catheter-related infections: current controversies.

Prevention of vascular catheter-related infection remains an important priority. This review focuses on salient controversies regarding optimal preventive methods. Intensity of surveillance for nosocomial infections was the single most important predictor of prevention in the Study of the Efficacy of Nosocomial Infection Control (SENIC). Used suboptimally by most hospitals in the SENIC study, surveillance is probably conducted even less today. There has been one randomized trial of the optimal method of aseptic insertion for central venous catheters and none comparing the 2 most frequently used sites. Scheduled replacement did not prevent infection in multiple randomized trials but, according to a recent survey, was still being used frequently. Chlorhexidine preparation of skin before and during catheterization has significantly reduced colonization of catheters in multiple randomized trials and should be used. Impregnation of catheter and/or hub surfaces with antiseptics raises less concern about fostering the development of antibiotic resistance than does the use of antibiotics for this purpose.

Guidelines for the management of intravascular catheter-related infections.

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 i.v. 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. For management of bacteremia and fungemia from a tunneled catheter or implantable device, such as a port, the decision to remove the catheter or device should be based on the severity of the patient's illness, documentation that the vascular-access device is infected, assessment of the specific pathogen involved, and presence of complications, such as endocarditis, septic thrombosis, tunnel infection, or metastatic seeding. When a catheter-related infection is documented and a specific pathogen is identified, systemic antimicrobial therapy should be narrowed and consideration given for antibiotic lock therapy, if the CVC or implantable device is not removed. These guidelines address the issues related to the management of catheter-related bacteremia and associated complications. Separate guidelines will address specific issues related to the prevention of catheter-related infections. Performance indicators for the management of catheter-related infection are included at the end of the document. Because the pathogenesis of catheter-related infections is complicated, the virulence of the pathogens is variable, and the host factors have not been well defined, there is a notable absence of compelling clinical data to make firm recommendations for an individual patient. Therefore, the recommendations in these guidelines are intended to support, and not replace, good clinical judgment. Also, a section on selected, unresolved clinical issues that require further study and research has been included. There is an urgent need for large, well-designed clinical studies to delineate management strategies more effectively, which will improve clinical outcomes and save precious health care resources.

Amebiasis and mucosal IgA antibody against the Entamoeba histolytica adherence lectin in Bangladeshi children.

Amebiasis is the third leading parasitic cause of death worldwide, and it is not known whether immunity is acquired from a previous infection. An investigation was done to determine whether protection from intestinal infection correlated with mucosal or systemic antibody responses to the Entamoeba histolytica GalNAc adherence lectin. E. histolytica colonization was present in 0% (0/64) of children with and 13.4% (33/246) of children without stool IgA anti-GalNAc lectin antibodies (P= .001). Children with stool IgA lectin-specific antibodies at the beginning of the study had 64% fewer new E. histolytica infections by 5 months (3/42 IgA(+) vs. 47/227 IgA(-); P= .03). A stool antilectin IgA response was detected near the time of resolution of infection in 67% (12/18) of closely monitored new infections. It was concluded that a mucosal IgA antilectin antibody response is associated with immune protection against E. histolytica colonization. The demonstration of naturally acquired immunity offers hope for a vaccine to prevent amebiasis.

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

Pseudoepidemic of streptococcal pharyngitis in a hospital pharmacy.

CONTEXT: Streptococcus pyogenes has recently re-emerged as a significant pathogen causing disease ranging from pharyngitis to lethal systemic infection. Six hospital pharmacy employees were diagnosed as having streptococcal pharyngitis during 1 week, and antibiotic prophylaxis was requested to halt the outbreak. OBJECTIVE: Outbreak investigation. DESIGN: Review of initial cases and prospective evaluation of the remaining pharmacy employees and the antigen detection test being used. SETTING: Pharmacy and occupational health department of a university hospital. POPULATION: Sixteen employees of the hospital pharmacy and 19 other employees of the hospital. RESULTS: The 6 pharmacy employees who had positive streptococcal antigen detection tests did not have symptoms suggesting streptococcal pharyngitis. Of the 10 remaining pharmacy employees, none had a positive throat culture for S pyogenes. Specificity of the antigen detection test being used was 53% (95% CI, 30%-75%) in prospective evaluation. CONCLUSIONS: This was believed to represent a pseudoepidemic because none of the 6 cases had signs or symptoms typical of streptococcal pharyngitis, none of the remaining 10 pharmacy employees had positive throat cultures, and prospective evaluation found low specificity of the antigen detection test. Whereas use of an accurate test in such a low prevalence setting could have resulted in a higher percentage of results being false-positive, the low specificity of the antigen detection test being used also contributed to the pseudoepidemic.

Diagnostic tests for healthcare epidemiology.

Diagnostic tests are important tools for surveillance in healthcare epidemiology. Recent studies regarding the use of diagnostic tests for detecting the following epidemiologically important conditions or pathogens are reviewed: vancomycin-resistant enterococci, Legionella, influenza, ventilator-associated pneumonia, Clostridium difficile, bloodstream infection, and tuberculosis.

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.

Risk factors for community-acquired pneumonia diagnosed upon hospital admission. British Thoracic Society Pneumonia Study Group.

A case-control study of risk factors for community-acquired pneumonia in adults admitted to hospital is reported. Cases were surviving patients (n = 178) admitted to 14 hospitals in England. Controls were individuals (n = 385) randomly selected from the electoral registers of the areas served by the hospitals. The two groups were compared with regard to risk factors for pneumonia using a standardized postal questionnaire. Independent risk factors associated with cases in log-linear regression analysis were age, heart disease (as indicated by congestive heart failure and/or digitalis treatment), lifetime smoking history, chronic airway disease (chronic bronchitis and/or asthma), occupational dust exposure, pneumonia as a child, single marital status and unemployment. Corticosteroid and bronchodilator therapy were also independent risk factors in the log-linear regression analysis, but may reflect the severity of underlying lung disease for which these drugs were prescribed. These data suggest that cigarette smoking is the major avoidable risk factor for acute pneumonia in adults.

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.

Incubation period and sources of exposure for cutaneous Mycobacterium marinum infection: case report and review of the literature.

The diagnosis of cutaneous Mycobacterium marinum infection is often delayed for months after presentation, perhaps because important clinical clues in the patient's history are frequently overlooked. Knowledge of the incubation period allows the clinician to target questions about the patient's history. Prompted by a case with a prolonged incubation period, we sought to determine more precisely the incubation period of M. marinum infection. The MEDLINE database for the period 1966-1996 was searched for information regarding incubation period and type of exposure preceding M. marinum infection. Ninety-nine articles were identified, describing 652 cases. Forty cases had known incubation periods (median, 21 days; range, 5-270 days). Thirty-five percent of cases had an incubation period > or =30 days. Of 193 infections with known exposures, 49% were aquarium-related, 27.4% were related to fish or shellfish injuries, and 8.8% were related to injuries associated with saltwater or brackish water. Because the incubation period for cutaneous M. marinum infection can be prolonged, patients with atypical cutaneous infections should be questioned about high-risk exposures that may have occurred up to 9 months before the onset of symptoms.

Glove leakage rates as a function of latex content and brand: caveat emptor.

HYPOTHESIS: That water leakage rates and protection against blood-borne pathogens should not vary as a function of latex content among Food and Drug Administration-approved gloves, allowing avoidance of unnecessary latex exposure. DESIGN AND METHODS: Eighteen different glove types were purchased and tested using the American Society for Testing Methods Standard Test for Detecting Holes in medical gloves, which involves mounting the glove on a plastic tube, pouring a liter of tap water into the glove, and visually inspecting the glove initially and after 2 minutes. Half of the gloves were tested straight from the package and half after a standardized manipulation. SETTING: A university hospital. RESULTS: Eleven sterile glove types (5 high latex content, 4 low latex content, and 2 nonlatex content), and 7 nonsterile examination glove types (2 high latex content, 2 low latex content, and 3 nonlatex content) were tested (total tested, 3720 gloves). Leakage rates were greater for examination than for surgical gloves (relative risk [RR], 1.41, 95% confidence interval [CI], 1.01-1.96), for manipulated than for unused gloves (RR, 2.89, 5% CI, 1.98-4.22), and for low latex content surgical gloves (RR, 2.58, 95% CI, 1.35-4.92) or nonlatex content surgical gloves (RR, 4.93, 95% CI, 2.35-10.32) than for high latex content surgical gloves. Significant differences were observed among low latex content surgical gloves (P

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.

Hand hygiene rates unaffected by installation of dispensers of a rapidly acting hand antiseptic.

OBJECTIVE: The objective of the study was to improve health care workers' compliance with hand hygiene after patient contact by use of an alcohol-based hand antiseptic. DESIGN AND METHODS: Six commercially available alcohol-based hand antiseptics were evaluated. The one most pleasing to the evaluators' hands was selected for the study. Baseline handwashing rates were assessed on 2 medical wards. Alcohol dispensers were mounted by every door on the 2 wards. An educational campaign was conducted with 4 weekly visits to these floors to remind and reinstruct staff about the use of the alcohol dispensers and to address questions. After 2 months handwashing rates were reassessed. SETTING: The study was set in a university hospital. RESULTS: The baseline handwashing rate was 60% (76/126). Physicians were most compliant (83%), followed by nurses (60%), technologists (56%), and housekeepers (36%). Two months later overall hand hygiene rates had decreased to 52% (P = .26). Nurses were most compliant (67%), followed by technologists (57%), physicians (29%), and housekeepers (25%). Physician compliance was associated with compliance by attending physicians whose example was usually followed by all other physicians on rounds. CONCLUSIONS: A brief educational campaign and installation of dispensers containing a rapidly acting hand hygiene product near hospital rooms did not affect hand hygiene compliance. The behavior of attending physicians was predictive of handwashing rates for all others in the attending's retinue. Compliance with handwashing after half of all patient contacts was a result of perfect compliance by some and total noncompliance by others being observed.