Increased catheter-related bloodstream infection rates after the introduction of a new mechanical valve intravenous access port

The technology of intravenous catheter access ports has evolved from open ports covered by removable caps to more-sophisticated, closed versions containing mechanical valves. We report a significant increase in catheter-related bloodstream infections after the introduction of a new needle-free positive-pressure mechanical valve intravenous access port at our institution.

Effect of a second-generation venous catheter impregnated with chlorhexidine and silver sulfadiazine on central catheter-related infections: a randomized, controlled trial

BACKGROUND

Central venous catheter-related infections are a significant medical problem. Improved preventive measures are needed.

OBJECTIVE

To ascertain 1) effectiveness of a second-generation antiseptic-coated catheter in the prevention of microbial colonization and infection; 2) safety and tolerability of this device; 3) microbiology of infected catheters; and 4) propensity for the development of antiseptic resistance.

DESIGN

Multicenter, randomized, double-blind, controlled trial.

SETTING

9 university-affiliated medical centers.

PATIENTS

780 patients in intensive care units who required central venous catheterization.

INTERVENTION

Patients received either a standard catheter or a catheter coated with chlorhexidine and silver sulfadiazine.

MEASUREMENTS

The authors assessed catheter colonization and catheter-related infection, characterized microbes by molecular typing, and determined their susceptibility to antiseptics. Patient tolerance of the catheter was monitored.

RESULTS

Patients with the 2 types of catheters had similar demographic features, clinical interventions, laboratory values, and risk factors for infection. Antiseptic catheters were less likely to be colonized at the time of removal compared with control catheters (13.3 vs. 24.1 colonized catheters per 1000 catheter-days; P < 0.01). The center-stratified Cox regression hazard ratio for colonization controlling for sampling design and potentially confounding variables was 0.45 (95% CI, 0.25 to 0.78). The rate of definitive catheter-related bloodstream infection was 1.24 per 1000 catheter-days (CI, 0.26 to 3.62 per 1000 catheter-days) for the control group versus 0.42 per 1000 catheter-days (CI, 0.01 to 2.34 per 1000 catheter-days) for the antiseptic catheter group (P = 0.6). Coagulase-negative staphylococci and other gram-positive organisms were the most frequent microbes to colonize catheters. Noninfectious adverse events were similar in both groups. Antiseptic susceptibility was similar for microbes recovered from either group.

LIMITATIONS

The antiseptic catheter was not compared with an antibiotic-coated catheter, and no conclusion can be made regarding its effect on bloodstream infection.

CONCLUSIONS

The second-generation chlorhexidine-silver sulfadiazine catheter is well tolerated. Antiseptic coating appears to reduce microbial colonization of the catheter compared with an uncoated catheter.

Handheld computer surveillance: shoe-leather epidemiology in the "palm" of your hand

BACKGROUND

Although urinary tract infections (UTIs) are the most common nosocomial infection, active UTI surveillance is often not feasible for infection control departments.

METHODS

As part of an ongoing urinary catheter evaluation, we investigated the accuracy and cost-effectiveness of using handheld personal digital assistants (PDA) and computer-based UTI surveillance in comparison with traditional surveillance of UTIs among medical intensive care unit (MICU) patients. From September 22, 2000, to October 22, 2000, an infection control practitioner (ICP) actively surveyed all MICU patients who had a urinary catheter to determine criteria for a nosocomial UTI as defined by the Centers for Disease Control and Prevention (CDC). Research assistants visited the unit each day to determine which patients had urinary catheters, and this information was uploaded to a database designed for laboratory-based UTI surveillance. Patients with a urinary catheter were included if admitted to the MICU for >48 hours and excluded if symptoms developed <48 hours after admission.

RESULTS

Both data collection methods identified 8 UTIs within the 1-month period, with 3 UTIs meeting inclusion criteria. Traditional surveillance required 8 hours weekly, whereas the PDA-computer surveillance required 1-and-a-half hours weekly. Traditional surveillance correctly attributed all 3 UTIs to the MICU. The PDA-computer surveillance incorrectly attributed the location of 2 of the UTIs. In both cases, the UTI occurred less than 48 hours after the patient was transferred from the MICU.

CONCLUSION

Our data demonstrate that PDA surveillance detects nosocomial UTIs efficiently and is a novel, timesaving technique that realizes a cost savings in the first year.

Ability of Physicians to Diagnose and Manage Illness Due to Category A Bioterrorism Agents

BACKGROUND

Early recognition of a terrorist attack with biologic agents will rely on physician diagnosis. Physicians' ability to diagnose and care for patients presenting after a bioterror event is unknown. The role of online case-based didactics to measure and improve knowledge in the diagnosis and treatment of these patients is unknown.

METHODS

A multicenter online educational intervention was completed by 631 physicians at 30 internal medicine residency programs in 16 states and Washington, DC, between July 1, 2003, and June 10, 2004. Participants completed a pretest, assessing ability to diagnose and manage potential cases of smallpox, anthrax, botulism, and plague. A didactic module reviewing diagnosis and management of these diseases was then completed, followed by a posttest. Pretest performance measured baseline knowledge. Posttest performance compared with pretest performance measured effectiveness of the educational intervention. Results were compared based on year of training and geographic location of the residency program.

RESULTS

Correct diagnoses of diseases due to bioterrorism agents were as follows: smallpox, 50.7%; anthrax, 70.5%; botulism, 49.6%; and plague, 16.3% (average, 46.8%). Correct diagnosis averaged 79.0% after completing the didactic module (P<.001). Correct management of smallpox was 14.6%; anthrax, 17.0%; botulism, 60.2%; and plague, 9.7% (average, 25.4%). Correct management averaged 79.1% after completing the didactic module (P<.001). Performance did not differ based on year of training (P = .54) or geographic location (P = .64). Attending physicians performed better than residents (P<.001).

CONCLUSIONS

Physician diagnosis and management of diseases caused by bioterrorism agents is poor. An online didactic module may improve diagnosis and management of diseases caused by these agents.

Enhanced identification of postoperative infections among inpatients

Monitoring antimicrobial exposure and diagnosis codes for certain procedures identifies more postoperative infections than routine surveillance methods.

We evaluated antimicrobial exposure, discharge diagnoses, or both to identify surgical site infections (SSI). This retrospective cohort study in 13 hospitals involved weighted, random samples of records from 8,739 coronary artery bypass graft (CABG) procedures, 7,399 cesarean deliveries, and 6,175 breast procedures. We compared routine surveillance to detection through inpatient antimicrobial exposure (>9 days for CABG, >2 days for cesareans, and >6 days for breast procedures), discharge diagnoses, or both. Together, all methods identified SSI after 7.4% of CABG, 5.0% of cesareans, and 2.0% of breast procedures. Antimicrobial exposure had the highest sensitivity, 88%–91%, compared with routine surveillance, 38%–64%. Diagnosis codes improved sensitivity of detection of antimicrobial exposure after cesareans. Record review confirmed SSI after 31% to 38% of procedures that met antimicrobial surveillance criteria. Sufficient antimicrobial exposure days, together with diagnosis codes for cesareans, identified more postoperative SSI than routine surveillance methods. This screening method was efficient, readily standardized, and suitable for most hospitals.

Nosocomial malaria and saline flush

An investigation of malaria in a US patient without recent travel established Plasmodium falciparum molecular genotype identity in 2 patients who shared a hospital room. P. falciparum can be transmitted in a hospital environment from patient to patient by blood inoculum if standard precautions are breached.

Risk of Mortality with a Bloodstream Infection Is Higher in the Less Severely Ill at Admission

RATIONALE

Health care-associated bloodstream infections are common in critically ill patients; however, investigators have had difficulty in quantifying the clinical impact of these infections given the high expected mortality among these patients.

OBJECTIVE

To estimate the impact of health care-associated bloodstream infections on in-hospital mortality after adjusting for severity of illness at critical care admission.

METHOD

A cohort of medical and surgical intensive care unit patients.

MEASUREMENTS

Severity of illness at admission, bloodstream infection, and in-hospital mortality.

MAIN RESULTS

Among the 2,783 adult patients, 269 developed unit-associated bloodstream infections. After adjusting for severity of illness, patients with a lower initial severity of illness who developed an infection had a greater than twofold higher risk for in-hospital mortality (hazard ratio [HR] = 2.42, 95% confidence interval [CI] 1.70, 3.44) when compared with patients without infection and with a similar initial severity of illness. In contrast, patients with a higher initial severity of illness who subsequently developed an infection did not have an increased risk for in-hospital mortality (HR = 0.96, 95%CI 0.76, 1.23) when compared with patients without infection but with a similar initial severity of illness.

CONCLUSIONS

These results suggest that these infections in less ill patients have a higher attributable impact on subsequent mortality than in more severely ill patients. Focusing interventions to prevent bloodstream infections in less severely ill patients would be expected to have a greater benefit in terms of mortality reduction.

Methicillin-resistant Staphylococcus caprae in a neonatal intensive care unit

Staphylococcus caprae, a hemolytic coagulase-negative staphylococcus that is infrequently associated with humans, was initially detected in specimens from six infants in our neonatal intensive care unit due to phenotypic characteristics common to methicillin-resistant Staphylococcus aureus. These isolates were subsequently identified as S. caprae by the Automated RiboPrinter microbial characterization system. This prompted an 8-month retrospective investigation in our neonatal intensive care unit. S. caprae was the cause of 6 of 18 episodes of coagulase-negative staphylococcal bacteremia, was the most common coagulase-negative staphylococcus recovered from the nares of 6 of 32 infants surveyed in a methicillin-resistant S. aureus surveillance program, and was isolated from 1 of 37 health care providers' hands. Of 13 neonatal intensive care unit isolates tested, all were methicillin resistant and positive for the mecA gene. All 21 isolates were found to be a single strain by Automated RiboPrinter and pulsed-field gel electrophoresis with ApaI or SmaI digestion; ApaI was more discriminating in analyzing epidemiologically unrelated strains than Automated RiboPrinter or electrophoresis with SmaI. These findings extend the importance of S. caprae, emphasize its similarities to methicillin-resistant S. aureus, and demonstrate its ability to persist in an intensive care unit setting.

An outbreak of multidrug-resistant Acinetobacter baumannii associated with pulsatile lavage wound treatment

CONTEXT

Pulsatile lavage is a high-pressure irrigation treatment used increasingly in a variety of health care settings to debride wounds. Infection control precautions are not routinely used during the procedure and are not included in pulsatile lavage equipment package labeling.

OBJECTIVES

To investigate an outbreak of multidrug-resistant Acinetobacter baumannii and to test the hypothesis that pulsatile lavage wound treatment was the mode of transmission for the organism.

DESIGN

Outbreak case-control investigation including case identification, review of medical records, environmental cultures, and pulsed-field gel electrophoresis.

SETTING

A 1000-bed tertiary care hospital in Baltimore, Md, during September and October 2003.

PATIENTS

The investigation included 11 patients infected or colonized with multidrug-resistant A baumannii. Seven of these patients met the case definition for the case-control study and were compared with 28 controls randomly selected from a list of inpatients without multidrug-resistant A baumannii who had a wound care consultation.

MAIN OUTCOME MEASURE

Infection or colonization with multidrug-resistant A baumannii.

RESULTS

Eleven patients had cultures that grew multidrug-resistant A baumannii during the outbreak period. Of the 10 health care-associated cases, 8 had received pulsatile lavage treatment. One strain of multidrug-resistant A baumannii was recovered from all 6 pulsatile lavage patients who had isolates available for pulsed-field gel electrophoresis analysis and from multiple surfaces in the wound care area. Six of 7 cases (86%) were treated with pulsatile lavage vs 4 of 28 controls (14%) (odds ratio, 36; 95% confidence interval, 2.8-1721; P<.001). These results confirm that pulsatile lavage was a significant risk factor for acquisition of multidrug-resistant A baumannii.

CONCLUSIONS

Transmission was apparently caused by dissemination of multidrug-resistant A baumannii during the pulsatile lavage procedure, resulting in environmental contamination. Appropriate infection control precautions should be used during pulsatile lavage therapy and should be included in pulsatile lavage equipment labeling.

Eliminating catheter-related bloodstream infections in the intensive care unit

OBJECTIVE

To determine whether a multifaceted systems intervention would eliminate catheter-related bloodstream infections (CR-BSIs).

DESIGN

Prospective cohort study in a surgical intensive care unit (ICU) with a concurrent control ICU.

SETTING

The Johns Hopkins Hospital.

PATIENTS

All patients with a central venous catheter in the ICU.

INTERVENTION

To eliminate CR-BSIs, a quality improvement team implemented five interventions: educating the staff; creating a catheter insertion cart; asking providers daily whether catheters could be removed; implementing a checklist to ensure adherence to evidence-based guidelines for preventing CR-BSIs; and empowering nurses to stop the catheter insertion procedure if a violation of the guidelines was observed.

MEASUREMENT

The primary outcome variable was the rate of CR-BSIs per 1,000 catheter days from January 1, 1998, through December 31, 2002. Secondary outcome variables included adherence to evidence-based infection control guidelines during catheter insertion.

MAIN RESULTS

Before the intervention, we found that physicians followed infection control guidelines during 62% of the procedures. During the intervention time period, the CR-BSI rate in the study ICU decreased from 11.3/1,000 catheter days in the first quarter of 1998 to 0/1,000 catheter days in the fourth quarter of 2002. The CR-BSI rate in the control ICU was 5.7/1,000 catheter days in the first quarter of 1998 and 1.6/1,000 catheter days in the fourth quarter of 2002 (p = .56). We estimate that these interventions may have prevented 43 CR-BSIs, eight deaths, and 1,945,922 dollars in additional costs per year in the study ICU.

CONCLUSIONS

Multifaceted interventions that helped to ensure adherence with evidence-based infection control guidelines nearly eliminated CR-BSIs in our surgical ICU.

Preoperative risk factors for nasal carriage of Staphylococcus aureus

BACKGROUND

Staphylococcus aureus nasal carriage is a risk factor for surgical-site infections (SSIs) caused by S. aureus, and eradication of carriage reduces postoperative nosocomial infections caused by it. No study has compared large groups of preoperative carriers and non-carriers to identify factors that are linked to S. aureus nasal carriage.

METHODS

While conducting a clinical trial evaluating whether mupirocin prevented S. aureus SSIs, we prospectively collected data on 70 patient characteristics that might be associated with S. aureus carriage. We performed stepwise logistic regression analysis.

RESULTS

Of the 4,030 patients, 891 (22%) carried S. aureus. Independent risk factors for S. aureus nasal carriage were obesity (odds ratio [OR], 1.29; 95% confidence interval [CI95], 1.11-1.50), male gender (OR, 1.29; CI95, 1.11-1.51), and a history of a cerebrovascular accident (OR, 1.53; CI95, 1.03-2.25) for all patients. Factors associated with nasal carriage varied somewhat by surgical specialty. In all groups, preoperative use of antimicrobial agents was independently associated with a lower risk of carrying S. aureus in the nares. Previously identified risk factors were not significantly associated with S. aureus nasal carriage in this large group of surgical patients.

CONCLUSION

Male gender, obesity, and a history of a cerebrovascular accident were identified as risk factors for S. aureus nasal carriage. It remains to be seen whether preoperative weight loss would reduce the rate of nasal carriage. In addition, the value of screening this patient population for S. aureus nasal carriage merits further investigation.

Staphylococcus aureus with reduced susceptibility to vancomycin

Infections with Staphylococcus aureus with reduced susceptibility to vancomycin continue to be reported, including 2 cases caused by S. aureus isolates with full resistance to vancomycin. This review first outlines the definitions of vancomycin-intermediate S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA) and risk factors for infection. Next, we describe the mechanisms of resistance and methods of laboratory detection of the organisms. Finally, we address infection control and management issues associated with isolation of VISA and VRSA.

Bronchoscope Reprocessing and Infection Prevention and Control

BACKGROUND

It has been recommended that bronchoscopists familiarize themselves with national recommendations for bronchoscope reprocessing practices, but the extent of guideline awareness is unclear.

METHODS

We distributed a survey to practicing bronchoscopists at two meetings. Questions addressed infection control issues related to bronchoscopy and specific reprocessing recommendations.

RESULTS

A total of 46 surveys were completed by medical directors of bronchoscopy suites (26%) and attending bronchoscopists (74%) who had graduated from medical school a median of 22 years ago and performed a median of 19 procedures per month. Sixty-five percent of respondents, including 55% of directors, were not familiar with national reprocessing recommendations, and 39% did not know the approach to reprocessing at their own institution. Respondents who did > 20 procedures per month trended toward being more likely to be aware of guidelines (54% vs 26%, p = 0.09) and were less likely to answer "do not know" to more than one question about specific reprocessing details (25% vs 70%, p = 0.003). Seventy-eight percent of respondents did not know local practices for at least one of the reprocessing details. Forty-six percent of respondents stated their institutions followed recommendations that records be kept of the specific bronchoscope used in each case.

CONCLUSIONS

Many experienced bronchoscopists are unfamiliar with national guidelines and local practices related to bronchoscope reprocessing. Publication of bronchoscope-specific, comprehensive reprocessing guidelines in the pulmonary literature may help increase familiarity with this crucial process.

Prevention of Staphylococcus aureus infections among surgical patients: Beyond traditional perioperative prophylaxis

BACKGROUND

Health care-related infections cause significant patient morbidity and mortality rates and add excess costs that frequently are not reimbursed. Staphylococcus aureus has long been recognized as an important pathogen in human disease and is the most common cause of nosocomial infections.

METHOD

The objective of this review of the English language literature and a MEDLINE search was to describe recent advances in the prevention of S aureus health care-related infections that are attributable to patients' endogenous colonization. The ecologic niche of S aureus is the anterior nares and nasal carriage increases the risk of the development of a surgical-site, lower respiratory tract, or bloodstream infection. S aureus carriers have a 2- to 9-fold increased risk of the development of a surgical-site or intravenous catheter infection.

RESULTS

Three treatment strategies may eliminate nasal carriage: locally applied antibiotics or disinfectants, systemic antibiotics, and bacterial interference. Among these strategies, locally applied or systemic antibiotics are used most commonly. Nasal ointments or sprays and oral antibiotics have variable efficacy, and their use frequently results in antimicrobial resistance among S aureus strains. Of the commonly used agents, mupirocin (pseudomonic acid) ointment has been shown to be 97% effective in reducing S aureus nasal carriage. In a recently published randomized, double-blind, placebo-controlled trial to determine whether intranasal mupirocin reduced the rate of S aureus-infected surgical-site and other S aureus health care-related infections; 4% of S aureus nasal carriers who received mupirocin acquired S aureus health care-related infections compared with 7.7% of S aureus nasal carriers who received placebo (P=.02). The S aureus surgical-site infection rate was not reduced significantly, but carriers who received mupirocin before cardiothoracic or general surgery operations had almost 50% fewer S aureus surgical-site infections than carriers who received placebo. In this setting resistance rarely has been reported.

CONCLUSIONS

Given the importance of S aureus nosocomial infections and the increased risk of S aureus nasal carriage in patients with health care-related infections, investigators must study cost-effective strategies to further prevent certain types of health care-related infections or nosocomial infections that occur in specific settings. One potential strategy is to decrease or eliminate S aureus nasal carriage among certain patient populations or in certain healthcare settings.

A 17-month evaluation of a chlorine dioxide water treatment system to control Legionella species in a hospital water supply

OBJECTIVE

To assess the safety and efficacy of a chlorine dioxide water treatment system in controlling Legionella in a hospital water supply.

DESIGN

For 17 months following installation of the system, we performed regular water cultures throughout the building, assessed chlorine dioxide and chlorite levels, and monitored metal corrosion.

RESULTS

Sites that grew Legionella species decreased from 41% at baseline to 4% (P = .001). L. anisa was the only species recovered and it was found in samples of both hot and cold water. Levels of chlorine dioxide and chlorite were below Environmental Protection Agency (EPA) limits for these chemicals in potable water. Further, enhanced carbon filtration effectively removed the chemicals, even at chlorine dioxide levels of more than twice what was used to treat the water. After 9 months, corrosion of copper test strips exposed to the chlorine dioxide was not higher than that of control strips. During the evaluation period, there were no cases of nosocomial Legionella in the building with the system, whereas there was one case in another building.

CONCLUSIONS

Our results indicate that operation of a chlorine dioxide system effectively removed Legionella species from a hospital water supply. Furthermore, we found that the system was safe, as levels of chlorine dioxide and chlorite were below EPA limits. The system did not appear to cause increased corrosion of copper pipes. Our results indicate that chlorine dioxide may hold promise as a solution to the problem of Legionella contamination of hospital water supplies.

Clinical implications of varying degrees of vancomycin susceptibility in methicillin-resistant Staphylococcus aureus bacteremia

We conducted a retrospective study of the clinical aspects of bacteremia caused by methicillin-resistant Staphylococcus aureus (MRSA) with heterogeneously reduced susceptibility to vancomycin. Bloodstream MRSA isolates were screened for reduced susceptibility by using brain-heart infusion agar, including 4 mg/L vancomycin with and without 4% NaCl. Patients whose isolates exhibited growth (case-patients) were compared with those whose isolates did not (controls) for demographics, coexisting chronic conditions, hospital events, antibiotic exposures, and outcomes. Sixty-one (41%) of 149 isolates exhibited growth. Subclones from 46 (75%) of these had a higher MIC of vancomycin than did their parent isolates. No isolates met criteria for vancomycin heteroresistance. No differences in potential predictors or in outcomes were found between case-patients and controls. These data show that patients with vancomycin-susceptible MRSA bacteremia have similar baseline clinical features and outcomes whether or not their bacterial isolates exhibit growth on screening media containing vancomycin.

Vancomycin-resistant enterococci: a road map on how to prevent the emergence and transmission of antimicrobial resistance

Nosocomial acquisition of microorganisms resistant to multiple antibiotics represents a threat to patient safety. Here we review the mechanisms that have allowed highly resistant strains belonging to the Enterococcus genus to proliferate within our health-care institutions. These mechanisms indicate that decreasing the prevalence of resistant organisms requires active surveillance, adherence to vigorous isolation, hand hygiene and environmental decontamination measures, and effective antibiotic stewardship. We suggest how to tailor such a complex, multidisciplinary program to the needs of a particular health-care setting so as to maximize cost-effectiveness.

Effect of nosocomial vancomycin-resistant enterococcal bacteremia on mortality, length of stay, and costs

OBJECTIVE

To determine the impact of vancomycin-resistant enterococcal bacteremia on patient outcomes and costs by assessing mortality, excess length of stay, and charges attributable to it.

DESIGN

A population-based, matched, historical cohort study.

SETTING

A 1,025-bed, university-based teaching facility and referral hospital.

PATIENTS

Two hundred seventy-seven vancomycin-resistant enterococcal bacteremia case-patients and 277 matched control-patients identified between 1993 and 2000.

RESULTS

The crude mortality rate was 50.2% and 19.9% for case-patients and control-patients, respectively, yielding a mortality rate of 30.3% attributable to vancomycin-resistant enterococcal bacteremia. The excess length of hospital stay attributable to vancomycin-resistant enterococcal bacteremia was 17 days, of which 12 days were spent in intensive care units. On average, dollars 77,558 in extra charges was attributable to each vancomycin-resistant enterococcal bacteremia. To adjust for severity of illness, 159 pairs of case-patients and control-patients, who had the same severity of illness (All Patient Refined-Diagnosis Related Group complexity level), were further analyzed. When patients were stratified by severity of illness, the crude mortality rate was 50.3% among case-patients compared with 27.7% among control-patients, accounting for an attributable mortality rate of 22.6%. Attributable excess length of stay and charges were 17 days and dollars 81,208, respectively.

CONCLUSION

Vancomycin-resistant enterococcal bacteremia contributes significantly to excess mortality and economic loss, once severity of illness is considered. Efforts to prevent these infections will likely be cost-effective.