Outcomes of primary and catheter-related bacteremia. A cohort and case-control study in critically ill patients

Acquired bloodstream infection in the intensive care unit: incidence and attributable mortality

INTRODUCTION

To estimate the incidence of intensive care unit (ICU)-acquired bloodstream infection (BSI) and its independent effect on hospital mortality.

METHODS

We retrospectively studied acquisition of BSI during admissions of >72 hours to adult ICUs from two university-affiliated hospitals. We obtained demographics, illness severity and co-morbidity data from ICU databases and microbiological diagnoses from departmental electronic records. We assessed survival at hospital discharge or at 90 days if still hospitalized.

RESULTS

We identified 6339 ICU admissions, 330 of which were complicated by BSI (5.2%). Median time to first positive culture was 7 days (IQR 5-12). Overall mortality was 23.5%, 41.2% in patients with BSI and 22.5% in those without. Patients who developed BSI had higher illness severity at ICU admission (median APACHE III score: 79 vs. 68, P < 0.001). After controlling for illness severity and baseline demographics by Cox proportional-hazard model, BSI remained independently associated with risk of death (hazard ratio from diagnosis 2.89; 95% confidence interval 2.41-3.46; P < 0.001). However, only 5% of the deaths in this model could be attributed to acquired-BSI, equivalent to an absolute decrease in survival of 1% of the total population. When analyzed by microbiological classification, Candida, Staphylococcus aureus and gram-negative bacilli infections were independently associated with increased risk of death. In a sub-group analysis intravascular catheter associated BSI remained associated with significant risk of death (hazard ratio 2.64; 95% confidence interval 1.44-4.83; P = 0.002).

CONCLUSIONS

ICU-acquired BSI is associated with greater in-hospital mortality, but complicates only 5% of ICU admissions and its absolute effect on population mortality is limited. These findings have implications for the design and interpretation of clinical trials.

[Impact of primary and intravascular catheter-related bacteremia due to coagulase-negative staphylococci in critically ill patients]

OBJECTIVE

To study the impact of coagulase-negative staphylococcal (CNS) primary and intravascular catheter-related bloodstream infection (PBSI/CRBSI) on mortality and morbidity in critically-ill patients.

DESIGN

We performed a double analysis using data from the ENVIN-HELICS registry data (years 1997 to 2008): 1) We studied the clinical characteristics and outcomes of patients with CNS-induced PBSI/CRBSI and compared them with those of patients with PBSI/CRBSI caused by other pathogens; and 2) We analyzed the impact of CNS-induced PBSI/CRBSI using a case-control design (1:4) in patients without other nosocomial infections.

SETTING

167 Spanish Intensive Care Units.

PATIENTS

Patients admitted to ICU for more than 24 hours.

RESULTS

2,252 patients developed PBSI/CRBSI, of which 1,133 were caused by CNS. The associated mortality for PBSI/CRBSI caused by non-CNS pathogens was higher than that of the CNS group (29.8% vs. 25.9%; P=.039) due exclusively to the mortality of patients with candidemia (mortality: 45.9%). In patients without other infections, PBSI/CRBSI caused by CNS (414 patients) is an independent risk factor for a higher than average length of ICU stay (OR: 5.81, 95% CI: 4.31-7.82; P<.001).

CONCLUSION

Crude mortality of patients with CNS-induced BPSI/CRBSI is similar to that of patients with BPSI/CRBSI caused by other bacteria, but lower than that of patients with candidemia. Compared to patients without nosocomial infections, CNS-induced PBSI/CRBSI is associated with a significant increase in length of ICU stay.

Current management of bloodstream infections

Bloodstream infection (BSI) is a frequent complication of invasive infections. The presence of bacteremia has therapeutic and prognostic implications. Here we review recent changes in the epidemiology, diagnosis and treatment of BSI (excluding candidemia). The evidence of the impact of healthcare-association in many community-onset episodes and the increase in drug-resistant pathogens causing BSI in the community and hospitals is reviewed. The emergence of molecular methods as an alternative tool for the diagnosis of BSI and novel aspects of clinical management, particularly of some multidrug-resistant organisms. Several quality indicators related to the diagnosis and management of bacteremia in hospitals are proposed.

Reduction in catheter-related bloodstream infections in critically ill patients through a multiple system intervention

In this study, we aimed to determine the utility of a multiple system intervention to reduce catheter-related bloodstream infections (CR-BSI) in our intensive care unit (ICU). A prospective cohort study was undertaken in the medical and surgical ICU at a university hospital. We applied five measures: educational sessions about inserting and maintaining central venous catheters, skin cleaning with chlorhexidine, a checklist during catheter insertion, subclavian vein insertion and avoiding femoral insertion whenever possible, and removing unnecessary catheters. We determined the rate of CR-BSI per 1,000 catheter-days during the intervention (March to December 2007) and compared it with the rate during the same period in 2006 in which we applied only conventional preventive measures. CR-BSI was defined as the recovery of the same organism (same species, same antibiotic susceptibility profile) from catheter tip and blood cultures. We registered 4,289 patient-days and 3,572 catheter-days in the control period and 4,174 patient-days and 3,296 catheter-days in the intervention period. No significant differences in the number of patients with central venous catheters during the two periods were observed: catheters were used in 81.5% of patients during the control period and in 80.6% of patients during the intervention period. During the control period, 24 CR-BSI were diagnosed (6.7/1,000 catheter-days); during the intervention period, 8 CR-BSI were diagnosed (2.4/1,000 catheter-days) (relative risk 0.36; 95% confidence interval [CI] 0.16 to 0.80; p = 0.015). Nurses interrupted the procedure to correct at least one aspect when completing the checklist in 17.7% of insertions. In conclusion, a multiple system intervention applying evidence-based measures reduced the incidence of CR-BSI in our ICU.

Hospital costs of central line-associated bloodstream infections and cost-effectiveness of closed vs. open infusion containers. The case of Intensive Care Units in Italy

Objectives

The aim was to evaluate direct health care costs of central line-associated bloodstream infections (CLABSI) and to calculate the cost-effectiveness ratio of closed fully collapsible plastic intravenous infusion containers vs. open (glass) infusion containers.

Methods

A two-year, prospective case-control study was undertaken in four intensive care units in an Italian teaching hospital. Patients with CLABSI (cases) and patients without CLABSI (controls) were matched for admission departments, gender, age, and average severity of illness score. Costs were estimated according to micro-costing approach. In the cost effectiveness analysis, the cost component was assessed as the difference between production costs while effectiveness was measured by CLABSI rate (number of CLABSI per 1000 central line days) associated with the two infusion containers.

Results

A total of 43 cases of CLABSI were compared with 97 matched controls. The mean age of cases and controls was 62.1 and 66.6 years, respectively (p = 0.143); 56% of the cases and 57% of the controls were females (p = 0.922). The mean length of stay of cases and controls was 17.41 and 8.55 days, respectively (p < 0.001). Overall, the mean total costs of patients with and without CLABSI were € 18,241 and € 9,087, respectively (p < 0.001). On average, the extra cost for drugs was € 843 (p < 0.001), for supplies € 133 (p = 0.116), for lab tests € 171 (p < 0.001), and for specialist visits € 15 (p = 0.019). The mean extra cost for hospital stay (overhead) was € 7,180 (p < 0.001). The closed infusion container was a dominant strategy. It resulted in lower CLABSI rates (3.5 vs. 8.2 CLABSIs per 1000 central line days for closed vs. open infusion container) without any significant difference in total production costs. The higher acquisition cost of the closed infusion container was offset by savings incurred in other phases of production, especially waste management.

Conclusions

CLABSI results in considerable and significant increase in utilization of hospital resources. Use of innovative technologies such as closed infusion containers can significantly reduce the incidence of healthcare acquired infection without posing additional burden on hospital budgets.

Prevention of central venous catheter-related infection: update

Central venous catheters (CVCs) are an essential part of modern-day healthcare, but infections associated with these devices continue to cause significant morbidity and mortality. There are many approaches for the prevention of CVC-related infection and these are outlined in national guidelines. The Department of Health Saving Lives campaign has developed a care-bundle for the prevention of CVC-related infections that focuses on the fundamental actions to be undertaken during the catheter insertion process and ongoing care. If the rate of catheter-related infection remains high despite the implementation of these infection prevention strategies, the use of novel antimicrobial technologies and practices may be considered. These include CVCs that contain antimicrobial agents, such as antiseptics or antibiotics, needleless intravenous (IV) access devices coated with silver and/or chlorhexidine, IV dressings incorporating chlorhexidine, and the use of antimicrobial catheter lock solutions, such as antibiotics, chelators or ethanol. This article outlines the different types of CVCs available, the risk of infection associated with their use and established and novel measures for prevention of these infections.

[Epidemiology of the primary and vascular catheter-related bacteriemias in critical patients admitted to an Intensive Medicine Department]

OBJECTIVE

In recent years, changes have occurred in the setting of bacteriemia related with the use of vascular catheters (BVC) and with the appearance of multiresistant gram positive cocci (MR-GPC), knowledge of the limitations regarding the antibiotics used most for their treatment (glycopeptides) and the appearance of new antibiotics active against these pathogens. This article analyzes the evolution of the rates, etiologies and markers of multiresistance of the most common pathogens in the BVC (including the primary bacteriemias) in the Spanish Intensive Medicine Departments (ICU).

MATERIAL AND METHODS

A multicenter, prospective, observational study of incidence, with voluntary participation, was conducted. A total of 74, 105, 112 and 121 ICUs belonging to 71, 97, 103 and 112 hospitals, respectively, collaborated including the years 2005-2008. The information included in the ENVIN-HELICS registry was used.

RESULTS

The rates of this complication have decreased and are now at about 5 episodes per 1,000 days of central venous catheter (CVC). One third of the episodes occur with significant systemic response (severe sepsis or septic shock). The MR-GPC were the most frequent, however Gram-negative bacilli (GNB) were identified in 30% of the cases and fungi (different species of Candida) in 6%. Staphylococcus epidermidis and coagulase-negative, methicillin-resistant staphylococci (CNS) persist in a proportion greater than 80%, while methicillin-resistance S. aureus have decreased to less than 40%.

CONCLUSIONS

The empirical treatment in situations of extreme seriousness should consider coverage of the most frequent pathogens such as the MR-GPC and GNB and in special conditions, the fungi.

Gram-negative bacteremia induces greater magnitude of inflammatory response than Gram-positive bacteremia

INTRODUCTION

Bacteremia is recognized as a critical condition that influences the outcome of sepsis. Although large-scale surveillance studies of bacterial species causing bacteremia have been published, the pathophysiological differences in bacteremias with different causative bacterial species remain unclear. The objective of the present study is to investigate the differences in pathophysiology and the clinical course of bacteremia caused by different bacterial species.

METHODS

We reviewed the medical records of all consecutive patients admitted to the general intensive care unit (ICU) of a university teaching hospital during the eight-year period since introduction of a rapid assay for interleukin (IL)-6 blood level to routine ICU practice in May 2000. White blood cell count, C-reactive protein (CRP), IL-6 blood level, and clinical course were compared among different pathogenic bacterial species.

RESULTS

The 259 eligible patients, as well as 515 eligible culture-positive blood samples collected from them, were included in this study. CRP, IL-6 blood level, and mortality were significantly higher in the septic shock group (n = 57) than in the sepsis group (n = 127) (P < 0.001). The 515 eligible culture-positive blood samples harbored a total of 593 isolates of microorganisms (Gram-positive, 407; Gram-negative, 176; fungi, 10). The incidence of Gram-negative bacteremia was significantly higher in the septic shock group than in the sepsis group (P < 0.001) and in the severe sepsis group (n = 75, P < 0.01). CRP and IL-6 blood level were significantly higher in Gram-negative bacteremia (n = 176) than in Gram-positive bacteremia (n = 407) (P < 0.001, <0.0005, respectively).

CONCLUSIONS

The incidence of Gram-negative bacteremia was significantly higher in bacteremic ICU patients with septic shock than in those with sepsis or severe sepsis. Furthermore, CRP and IL-6 levels were significantly higher in Gram-negative bacteremia than in Gram-positive bacteremia. These findings suggest that differences in host responses and virulence mechanisms of different pathogenic microorganisms should be considered in treatment of bacteremic patients, and that new countermeasures beyond conventional antimicrobial medications are urgently needed.

Clinical practice guidelines for the diagnosis and management of intravascular catheter-related infection: 2009 Update by the Infectious Diseases Society of America

These updated guidelines replace the previous management guidelines published in 2001. The guidelines are intended for use by health care providers who care for patients who either have these infections or may be at risk for them.

Antimicrobial catheters in the ICU: is the juice worth the squeeze?

Catheter-related bloodstream infection is one of the most serious complications of central venous access devices. Antimicrobial-coated catheters represent one novel strategy to prevent catheter-related bloodstream infection. A comprehensive economic evaluation is essential to guide informed decision-making regarding the adoption of this technology and its expected benefits in healthcare institutions.

Epidemiology and outcome of nosocomial bloodstream infection in elderly critically ill patients: a comparison between middle-aged, old, and very old patients

BACKGROUND

We investigated the epidemiology of nosocomial bloodstream infection in elderly intensive care unit (ICU) patients.

METHODS

In a single-center, historical cohort study (1992-2006), we compared middle-aged (45-64 years; n = 524), old(65-74 years; n = 326), and very old ICU patients (> 75 years; n = 134) who developed a nosocomial bloodstream infection during their ICU stay.

RESULTS

Although the total number of ICU admissions (patients aged > or = 45 years) decreased by approximately 10%, the number of very old patients increased by 33% between the periods 1992-1996 and 2002-2006. The prevalence of bloodstream infection (per 1,000 ICU admissions) increased significantly over time among old (p = 0.001) and very old patients (p = 0.002), but not among middle-aged patients (p = 0.232). Yet, this trend could not be confirmed with the incidence data expressed per 1,000 patient days (p > 0.05). Among patients with bloodstream infection, the proportion of very old patients increased significantly with time from 7.2% (1992-1996) to 13.5% (1997-2001) and 17.4% (2002-2006) (p <0.001). The incidence of bloodstream infection (per 1000 patient days) decreased with age: 8.4 per thousand in middle-aged, 5.5 per thousand in old, and 4.6 per thousand in very old patients (p < 0.001). Mortality rates increased with age: 42.9%, 49.1%, and 56.0% for middle-aged, old, and very old patients, respectively (p = 0.015). Regression analysis revealed that the adjusted relationship with mortality was borderline significant for old age (hazard ratio, 1.2; 95% confidence interval, 1.0 -1.5) and significant for very old age (hazard ratio,1.8; 95% confidence interval, 1.4 -2.4).

CONCLUSION

Over the past 15 years, an increasing number of elderly patients were admitted to our ICU. The incidence of nosocomial bloodstream infection is lower among very old ICU patients when compared to middle-aged and old patients. Yet, the adverse impact of this infection is higher in very old patients.

Incidence rate and variable cost of nosocomial infections in different types of intensive care units

OBJECTIVE

Nosocomial infection (NI) is one of the most serious healthcare issues currently influencing healthcare costs. This study estimates the impact of NI on costs in intensive care units (ICUs).

DESIGN

Prospective surveillance by a retrospective cohort study.

SETTING

A medical ICU, a surgical ICU, and a mixed medical and surgical ICU in a large tertiary referral medical center.

METHODS

Surveillance for NIs was conducted for all patients admitted to adult ICUs from 2003 through 2005. Retrospective chart review was conducted for each patient. The generalized linear modeling approach was used to assess the relationship of NIs to the increase in variable costs in individual ICUs and in all ICUs.

RESULTS

A total of 401 NIs occurred in 320 of 2,757 screened patients. The incidence rate was 12.1% in the medical ICU, 14.7% in the surgical ICU, and 16.7% in the mixed medical and surgical ICU (P>.05). All of the mean variable costs were significantly higher for patients with NI than they were for patients without NI, after controlling for covariates. The medical ICU had the greatest increase in mean cost ($13,456, which was 3.52 times [95% confidence interval {CI}, 2.94-4.22 times] the mean cost for patients without NI), followed by the mixed medical and surgical ICU ($6,748, which was 2.74 times [95% CI, 2.33-3.22 times] the mean cost for patients without NI) and the surgical ICU ($5,433, which was 2.46 times [95% CI, 1.99-3.05 times] the mean cost for patients without NI). Mean cost increases according to the site of NI were $6,056 for bloodstream infection (2.36 times [95% CI, 1.97-2.84 times] the mean cost for patients without NI), $4,287 for respiratory tract infection (1.91 times [95% CI, 1.57-2.32 times] the mean cost for patients without NI), $1,955 for urinary tract infection (1.42 times [95% CI, 1.18-1.72 times] the mean cost for patients without NI), and $1,051 for surgical site infection (1.23 times [95% CI, 0.90-1.68 times] the mean cost for patients without NI).

CONCLUSIONS

The medical ICU had the lowest rate of NI and the largest excess costs, the surgical ICU had the lowest excess costs, and the mixed medical and surgical ICU had the highest rate of NI. The cost is largely attributable to bloodstream infection and respiratory tract infection.

Complicated skin and skin-structure infections and catheter-related bloodstream infections: noninferiority of linezolid in a phase 3 study

BACKGROUND

Catheter-related bloodstream infection (CRBSI) causes substantial morbidity and mortality, but few randomized, controlled studies have been conducted to guide therapeutic interventions.

METHODS

To determine whether linezolid would be noninferior to vancomycin in patients with CRBSI, we conducted an open-label, multicenter, comparative study. Patients with suspected CRBSI were randomized to receive linezolid or vancomycin (control group). The primary end point was microbiologic outcome at test of cure 1-2 weeks after treatment, as assessed by step-down procedure. The first analysis population was complicated skin and skin structure infection (cSSSI) in patients with suspected CRBSI; patients with CRBSI were analyzed if noninferiority criteria (lower bound of the 95% confidence interval [CI] not outside -15%) were met.

RESULTS

Noninferiority criteria were met for cSSSI (microbiologic success rate for linezolid recipients, 89.6% [146 for 163 patients]; for the control group, 89.9% [134 of 149]; 95% CI, -7.1 to 6.4) and CRBSI (for linezolid recipients, 86.3% [82 of 95]; for the control group, 90.5% [67 of 74]; 95% CI, -13.8 to 5.4). The frequency and severity of adverse events were similar between groups. Mortality rates were 10.4% for linezolid recipients (28 of 269 patients) and 10.1% for control subjects (26 of 257) in the modified intent-to-treat population (i.e., all patients with gram-positive baseline culture) through test of cure, and they were 21.5% for linezolid recipients (78 of 363) and 16.0% for the control group (58 of 363; 95% CI, -0.2 to 11.2) for all treated patients through poststudy treatment day 84.

CONCLUSIONS

Linezolid demonstrated microbiologic success rates noninferior to those for vancomycin in patients with cSSSIs and CRBSIs caused by gram-positive organisms. Patients with catheter-related infections must be carefully investigated for the heterogeneous underlying causes of high morbidity and mortality, particularly for infections with gram-negative organisms.

Strategies to prevent central line-associated bloodstream infections in acute care hospitals

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections. The intent of this document is to highlight practical recommendations in a concise format designed to assist acute care hospitals in implementing and prioritizing their central line–associated bloodstream infection (CLABSI) prevention efforts. Refer to the Society for Healthcare Epidemiology of America/Infectious Diseases Society of America “Compendium of Strategies to Prevent Healthcare-Associated Infections” Executive Summary and Introduction and accompanying editorial for additional discussion.

1. Patients at risk for CLABSIs in acute care facilities

a. Intensive care unit (ICU) population: The risk of CLABSI in ICU patients is high. Reasons for this include the frequent insertion of multiple catheters, the use of specific types of catheters that are almost exclusively inserted in ICU patients and associated with substantial risk (eg, arterial catheters), and the fact that catheters are frequently placed in emergency circumstances, repeatedly accessed each day, and often needed for extended periods.

b. Non-ICU population: Although the primary focus of attention over the past 2 decades has been the ICU setting, recent data suggest that the greatest numbers of patients with central lines are in hospital units outside the ICU, where there is a substantial risk of CLABSI.

2. Outcomes associated with hospital-acquired CLABSI

a. Increased length of hospital stay

b. Increased cost; the non-inflation-adjusted attributable cost of CLABSIs has been found to vary from $3,700 to $29,000 per episode

Clinical use of disinfectable needle-free connectors

BACKGROUND

In 1992, the United States Food and Drug Administration required health care services to adopt needle-free devices to prevent health care workers' exposure to bloodborne pathogens resulting from needlestick injuries, and several systems of disinfectable needle-free connectors (DNC) were introduced.

STUDIES

MICROBIAL COLONIZATION: Experimental studies showed that DNCs designed with a split septum (SS-DNCs) and mechanical valve systems (MLV-DNC) prevented endoluminal colonization as effectively as needles or conventional caps. A comparison of the microbiologic barrier effect of SS-DNCs, MLV-DNCs, and passive positive-pressure (PPV)-DNCs found that PPV-DNCs were least effective in providing protection under experimental conditions of poor handling practices and high microorganism concentrations. PREVENTION OF CATHETER-RELATED BLOODSTREAM INFECTIONS: Some randomized trials show a positive or neutral effect of DNC use on the prevention of catheter-related bloodstream infections (CR-BSIs); however, some investigators have reported outbreaks of CR-BSIs following the introductions of DNCs that could be related to noncompliance with DNC handling recommendations or the use of PPV-DNCs.

CONCLUSION

Strategies focused in the implication of the nurse staff in CRBSI surveillance increase compliance with DNC handling recommendations and minimize the risk of developing a CR-BSI. DNCs can be used safely if staff complies with recommendations for use.

Prevention of catheter-related bloodstream infections

CRBSIs are expensive, prevalent, and often fatal complications. In the past few years, several preventive interventions have been applied with excellent results toward decreasing CRBSIs. Studies show that most CRBSIs are preventable; therefore, health care organizations should strive to substantially reduce if not eliminate them. In addition to being a measure of quality of care, reducing infections will soon be a bottom-line issue, given that the Centers for Medicare and Medicaid Services announced its decision to cease paying hospitals from October 2008 for some care necessitated by "preventable complications", including CRBSIs. Therefore, health care facilities that do not make the necessary adjustments to improve the quality of their patient care and avoid harm may be economically penalized. This article reviews the available evidence on and possible barriers to the widespread use of preventive strategies. The health care community has struggled to build a culture that can eliminate the barriers obstructing high-quality care. These new approaches must facilitate collaboration among caregivers. During the past few years, much effort has been dedicated to researching causes for inadequate patient care and executing interventions to improve processes of care; only now are projects beginning to focus on evaluating whether patients are safer. This article discusses the prevention of CRBSIs and shows that substantial reductions in the rate of these infections are possible. It is no longer acceptable for health care organizations to have the goal of being at the CDC mean for rate of infections; they should strive to substantially reduce or even eliminate them. Patients deserve no less.

Diabetes mellitus is an independent risk factor for ICU-acquired bloodstream infections

OBJECTIVE

To investigate the role of diabetes as risk factor for ICU-acquired bloodstream infections (BSI).

DESIGN

Prospective observational study.

SETTING

A general eight-bed ICU of a tertiary hospital.

PATIENTS

Three hundred and forty-three consecutive patients (63 diabetic and 280 nondiabetic) admitted in the ICU.

METHODS

BSI episodes in the ICU were recorded and classified as primary, secondary, catheter-related and mixed according to strict criteria. In all patients, blood glucose was strictly controlled with a continuous insulin infusion within a range of 80-120 mg/dl.

RESULTS

One-hundred and eighteen patients (34.4%) developed at least one BSI episode. Diabetic patients had an increased probability of developing at least one BSI episode compared with nondiabetic patients (hazard ratio = 1.66, 95% confidence interval 1.04-2.64, P = 0.034) in a Cox proportional hazards regression model adjusting for age, gender, admission category and APACHE II score at admission in the ICU and comorbidities.

CONCLUSIONS

Despite strict glycemic control, diabetic patients have a 1.7-fold probability of developing an ICU-acquired BSI compared to nondiabetic subjects.

[Impact on morbidity and costs of methicillin-resistant Staphylococcus aureus nosocomial pneumonia in intensive care patients]

OBJECTIVES

Prevention of methicillin-resistant Staphylococcus aureus (MRSA) nosocomial infections in the intensive care units (ICU) has been recommended for several years. However, the workload and the costs of these programs are to be weighed against the benefit obtained in terms of reduction of morbidity and costs induced by the infection. The purpose of this study was to evaluate the cost and the current morbidity of the infection with MRSA in the ICU.

METHODS

In a retrospective case-control study carried out in 2004, all patients of the 6 intensive care units of a teaching hospital having developed a MRSA nosocomial infection were included. They were paired with controls on the following criteria: department, Simplified Acute Physiology Score II (SAPSII), age (+/- 5 years), type of surgery (for the surgical intensive care units). The duration of hospitalization of the paired control had to be at least equal to the time from admission to infection of the infected patient. The costs were evaluated using the following parameters: scores omega 1, 2 and 3, duration of artificial ventilation, hemodialysis, length of ICU stay, radiological procedures, surgical procedures, total antibiotic cost and other expensive drugs.

RESULTS

Twenty-one patients with MRSA infection were included. All had nosocomial pneumonia. The 21 paired patients were similar with regard to both initial criteria and sex. Hospital mortality was not different between the 2 groups (cases=8; controls=6; p=0.41), as well as median duration of hospital stay (cases=41 days; controls=43 days; p=0.9). The duration of mechanical ventilation, number of hemodialysis or hemofiltration sessions, number of radiological procedures were similar in both groups. The total omega score was not significantly different between cases (median 435; IQR: 218-579) and controls (median 281, IQR: 231-419; p=0.55). The median duration of isolation was 12 days for cases and 0 day for controls (p=0.0007). The pharmaceutical expenditure was significantly higher in cases (median: 1414euro; IQR: 795-4349), by comparison with the controls (median: 877euro, IQR: 687-2496) (p=0.049).

CONCLUSION

In the ICU having set up a policy intended to reduce the risk of MRSA nosocomial infections, MRSA pneumonia does not seem to involve major additional morbidity, as compared to a control population matched for similar severity of illness. It increases modestly the use of the medical resources.

Impact of adverse events on outcomes in intensive care unit patients

OBJECTIVE

To examine the association between predefined adverse events (AE) (including nosocomial infections) and intensive care unit (ICU) mortality, controlling for multiple adverse events in the same patient and confounding variables.

DESIGN

Prospective observational cohort study of the French OUTCOMEREA multicenter database.

SETTING

Twelve medical or surgical ICUs.

PATIENTS

Unselected patients hospitalized for > or = 48 hrs enrolled between 1997 and 2003.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 3,611 patients included, 1415 (39.2%) experienced one or more AEs and 821 (22.7%) had two or more AEs. Mean number of AEs per patient was 2.8 (range, 1-26). Six AEs were associated with death: primary or catheter-related bloodstream infection (BSI) (odds ratio [OR], 2.92; 95% confidence interval [CI], 1.6-5.32), BSI from other sources (OR, 5.7; 95% CI, 2.66-12.05), nonbacteremic pneumonia (OR, 1.69; 95% CI, 1.17-2.44), deep and organ/space surgical site infection without BSI (OR, 3; 95% CI, 1.3-6.8), pneumothorax (OR, 3.1; 95% CI, 1.5-6.3), and gastrointestinal bleeding (OR, 2.6; 95% CI, 1.4-4.9). The results were not changed when the analysis was confined to patients with mechanical ventilation on day 1, intermediate severity of illness (Simplified Acute Physiology Score II between 35 and 55), no treatment-limitation decisions, or no cardiac arrest in the ICU.

CONCLUSIONS

AEs were common and often occurred in combination in individual patients. Several AEs independently contributed to death. Creating a safe ICU environment is a challenging task that deserves careful attention from ICU physicians.

Bloodstream infections: evolution and trends in the microbiology workload, incidence, and etiology, 1985-2006

Information available on bloodstream infection (BSI) is usually restricted to short periods of time, certain clinical backgrounds, or specific pathogens, or is just outdated. We conducted the current prospective study of patients with BSI in a 1750-bed teaching hospital to evaluate workload trends and the incidence and etiology of BSI in a general hospital during the last 22 years, including the acquired immunodeficiency syndrome (AIDS) era. The main outcome measures were laboratory workload, trends in incidence per 1000 admissions and per 100,000 population of different microorganisms, and the impact of the human immunodeficiency virus (HIV) epidemic in the period 1985-2006.From 1985 to 2006 we had 27,419 episodes of significant BSI (22,626 patients). BSI incidence evolved from 16.0 episodes to 31.2/1000 admissions showing an annual increase of 0.83 episodes/1000 admissions (95% confidence interval, 0.61-1.05; p < 0.0001). The evolution of the incidence per 1000 admissions and per 100,000 population of different groups of microorganisms was as follows: Gram positives 8.2 to 15.7/1000 admissions and 66.8 to 138.3/100,000 population; Gram negatives 7.8 to 16.2/1000 admissions and 63.5 to 141.9/100,000 population; anaerobes 0.5 to 1.3/1000 admissions and 4.1 to 11.7/100,000 population; and fungi 0.2 to 1.5/1000 admissions and 1.7 to 12.5/100,000 population. All those differences were statistically significant. We observed the emergence of multiresistant Gram-positive and Gram-negative microorganisms. At least 2484 episodes of BSI (9.1%) occurred in 1822 patients infected with HIV. The incidence of BSI in HIV-infected patients increased from 1985 and reached a peak in 1995 (17.6% of BSI). Since 1995, the decrease was continuous, and in 2006 only 3.9% of all BSI episodes occurred in HIV-positive patients in our institution. We conclude that the BSI workload has increased in modern microbiology laboratories. Gram-positive pathogens have overtaken other etiologic agents of BSI. Our observation shows the remarkable escalation of some resistant pathogens, and the rise and relative fall of BSI in patients with HIV.

Mortality associated with bloodstream infection after coronary artery bypass surgery

BACKGROUND

Mortality attributable to bloodstream infection (BSI) is still controversial. We studied the impact of BSI on mortality after coronary artery bypass surgery, including the specific impact of different etiologic organisms.

METHODS

Our cohort consisted of 4515 patients who underwent coronary artery bypass procedures at a university hospital from 1996 through 2004. We used Society of Thoracic Surgery data supplemented with laboratory and infection control data. Mortality dates were identified using Society of Thoracic Surgery data and the Social Security Death Index. BSI within 90 days after surgery was defined by a positive blood culture result. Cox proportional hazards and propensity score models were used to analyze the association between BSI and mortality.

RESULTS

Patients with BSI had a 4.2-fold increased risk of death (95% confidence interval [CI], 3.0-5.9) 2-90 days after coronary artery bypass surgery, compared with uninfected patients. The risk of death was higher among patients with BSI due to gram-negative bacteria (hazard ratio [HR], 6.8; 95% CI, 3.9-12.0) and BSI due to Staphylococcus aureus (HR, 7.2; 95% CI, 3.3-15.7) and lowest among patients with BSI caused by gram-positive bacteria other than S. aureus (HR, 2.2; 95% CI, 1.1-4.6). The risk of death was highest among patients who developed BSI but had the lowest likelihood of infection (HR, 10.0; 95% CI, 3.5-28.8) and was lowest among patients who developed BSI but had the highest likelihood of infection (HR, 2.3; 95% CI, 1.2-4.6).

CONCLUSIONS

BSIs due to gram-negative bacteria and BSIs due to S. aureus contributed significantly to mortality. Mortality attributable to BSI was highest among patients predicted to be least likely to develop infection and was lowest among severely ill patients who were most likely to develop infection. BSI appears to be an important contributor to death after coronary artery bypass surgery, particularly among the healthiest patients.

Oral care and the risk of bloodstream infections in mechanically ventilated adults: A review

RATIONALE

Bacteraemia, defined as the presence of viable bacteria in the circulating blood can result in bloodstream infection, which is one of the most frequent and challenging hospital-acquired infections. Bacteraemia occurs in healthy populations with manipulation of the oral mucosa, including toothbrushing. Oral care is commonly administered to mechanically ventilated patients, it is important to determine whether this practice contributes to the incidence of bacteraemia. This paper reviews the literature on the link between the manipulation of the oral cavity and the development of bacteraemia in mechanically ventilated adults.

METHODS

Searches were conducted using Medline, CINAHL, and the Cochrane Library databases. Article inclusion criteria were (1) a focus on mechanical ventilation and critical illness, (2) human subjects, (3) adult subjects, and (4) publication in English (or available English translation).

RESULTS

Nine articles met inclusion criteria and were critiqued. All relied upon clinical data as outcome measures; many were retrospective. The three organisms most often associated with nosocomial bloodstream infections were Staphylococcus aureus, coagulase negative staphylococci, and Enterococcus species. Establishing the origin of bacteraemia was problematic in most studies.

CONCLUSIONS

Additional research is needed to understand the relationship of oral care practices to bacteraemia in mechanically ventilated adults.

The impact of hospital practice on central venous catheter associated bloodstream infection rates at the patient and unit level: a multicenter study

OBJECTIVE

Little is known about factors driving variation in bloodstream infection (BSI) rates between institutions. The objectives of this study are to (1) identify patient, process of care, and hospital factors that influence intensive care unit (ICU)-level BSI rates and (2) compare those factors to individual risk factors identified in a cohort analysis.

DESIGN

In this multicenter prospective observational study, the authors measured the process of care for 2970 randomly sampled central venous catheter insertions over 13 months.

SETTING

Medical, surgical, and medical/surgical ICUs of 37 domestic and 13 international hospitals.

RESULTS

Significant correlates of unit-level BSI rates were percentage of female patients, patients on dialysis, ICU bed size, percentage of practitioners with low numbers of previous insertions, and percentage inserted by nurses. Patient-level analysis identified gender, age, posttransplant, postsurgery, and use of the line for parenteral nutrition.

CONCLUSIONS

Factors that influence unit-to-unit variation may differ from factors identified in studies of individual patient risk.

Costs and length of stay associated with antimicrobial resistance in acute kidney injury patients with bloodstream infection

INTRODUCTION

Antimicrobial resistance negatively impacts on prognosis. Intensive care unit (ICU) patients, and particularly those with acute kidney injury (AKI), are at high risk for developing nosocomial bloodstream infections (BSI) due to multi-drug-resistant strains. Economic implications in terms of costs and length of stay (LOS) attributable to antimicrobial resistance are underevaluated. This study aimed to assess whether microbial susceptibility patterns affect costs and LOS in a well-defined cohort of ICU patients with AKI undergoing renal replacement therapy (RRT) who developed nosocomial BSI.

METHODS

Historical study (1995-2004) enrolling all adult RRT-dependent ICU patients with AKI and nosocomial BSI. Costs were considered as invoiced in the Belgian reimbursement system, and LOS was used as a surrogate marker for hospital resource allocation.

RESULTS

Of the 1330 patients with AKI undergoing RRT, 92 had microbiologic evidence of nosocomial BSI (57/92, 62% due to a multi-drug-resistant microorganism). Main patient characteristics were equal in both groups. As compared to patients with antimicro-4 bial-susceptible BSI, patients with antimicrobial-resistant BSI were more likely to acquire Gram-positive infection (72.6% vs 25.5%, P<0.001). No differences were found neither in LOS (ICU before BSI, ICU, hospital before BSI, hospital, hospital after BSI, and time on RRT; all P>0.05) or hospital costs (all P>0.05) when comparing patients with antimicrobial-resistant vs antimicrobial-susceptible BSI. However, although not statistically significant, patients with BSI caused by resistant Gram-negative-, Candida-, or anaerobic bacteria incurred substantial higher costs than those without.

CONCLUSION

In a cohort of ICU patients with AKI and nosocomial BSI undergoing RRT, patients with antimicrobial-resistant vs antimicrobial-susceptible Gram-positive BSI did not have longer hospital stays, or higher hospital costs. Patients with resistant "other" (i.e. Gram-negative, Candida, or anaerobic) BSI were found to have a distinct trend towards increased resources use as compared to patients with susceptible "other" BSI, respectively.

Prevention of primary bacteraemia

This overview provides information on recent advances in the prevention of primary bacteraemia, commonly defined as bloodstream infection without a documented source of infection, but including those resulting from an intravenous or arterial line infection. The potential to prevent community-acquired, primary bacteraemia is still limited and may be targeted mainly at vaccines for high-risk groups. In contrast, the prevention of catheter-related bacteraemia has seen substantial progress within the last 10 years. Consequently, intravascular device-related bacteraemia has become largely preventable under routine working conditions. Independent of the use of antibiotic-coated catheters, the implementation of clinical pathways and multimodal preventive strategies directed at several risk factors of catheter-related bacteraemia is a successful strategy to reduce this potentially life-threatening infection and deserves future health services research.

Incidence and risk factors of device-associated infections and associated mortality at the intensive care in the Dutch surveillance system

OBJECTIVE

To examine the incidence of and risk factors for device-associated infections and associated mortality.

DESIGN AND SETTING

Prospective surveillance-based study in ICUs of 19 hospitals in The Netherlands.

PATIENTS

The study included 2,644 patients without infection at admission during 1997-2000, staying in the ICU for at least 48 h.

MEASUREMENTS AND RESULTS

The occurrence of ventilator-associated pneumonia (VAP), central venous catheter (CVC) related bloodstream infection (CR-BSI), urinary catheter-associated urinary tract infection (CA-UTI) and risk factors was monitored. Of the ventilated patients 19% developed pneumonia (25/1,000 ventilator days); of those with a central line 3% developed CR-BSI (4/1,000 CVC days,) and of catheterized patients 8% developed CA-UTI (9/1,000 catheter days). Longer device use increased the risk for all infections, especially for CR-BSI. Independent risk factors were sex, immunity, acute/elective admission, selective decontamination of the digestive tract, and systemic antibiotics at admission, dependent upon the infection type. Crude mortality significantly differed in patients with and without CR-BSI (31% vs. 20%) and CA-UTI (27% vs. 17%) but not for VAP (26% vs. 23%). Acquiring a device-associated infection was not an independent risk factor for mortality. Being in need of ventilation or a central line, and the duration of this, contributed significantly to mortality, after adjusting for other risk factors.

CONCLUSIONS

Device use was the major risk factor for acquiring VAP, CR-BSI and CA-UTI. Acquiring a device-associated infection was not an independent risk factor for mortality, but device use in itself was.

Prospective cohort study of central venous catheters among internal medicine ward patients

BACKGROUND

Central venous catheter (CVC) use is less well described for patients outside the intensive care unit. We evaluated CVCs and the associated bloodstream infection rate among patients admitted to the general medical service.

METHODS

We performed a prospective cohort study of patients who had a CVC on admission or inserted during their stay on the general medical service in a public teaching hospital, November 15, 2004, to March 31, 2005.

RESULTS

We identified 106 CVCs, 52 were present on admission and 54 were inserted; there were 682 catheter-days. The primary bloodstream infection rate was 4.4 per 1000 catheter-days (95% CI: 0.9-13): highest for catheters inserted in the emergency department compared with those inserted on other units (24 vs 1.7 per 1000 catheter-days), P = .045. By multivariable analysis, inadequate dressings were more likely among patients with a body mass index > or =30 kg/m(2), adjusted odds ratio, 3.4 (95% CI: 1.4-8.0).

CONCLUSIONS

Many CVCs had previously been inserted in the emergency department or intensive care unit; therefore, strategies to reduce bloodstream infections that focus on ward insertion practices may not dramatically reduce bloodstream infection rates. Intervention strategies should target improved dressing care and consideration of early removal or replacement of catheters inserted in the emergency department.