Impact of an antimicrobial stewardship-led intervention for Staphylococcus aureus bacteraemia: a quasi-experimental study.

BACKGROUND: Staphylococcus aureus bacteraemia (SAB) carries high rates of morbidity and mortality. Antimicrobial stewardship programmes (ASPs) are well situated to promote adherence to quality performance measures in order to optimize the management of SAB and associated clinical outcomes. METHODS: This uncontrolled pre-post quasi-experimental study evaluated compliance with an ASP-driven comprehensive care bundle and associated clinical outcomes for patients with SAB. The ASP provided recommendations to prescribers to promote adherence with quality performance measures, which included: initiate effective antibiotics within 24 h of Gram's stain; achieve therapeutic vancomycin trough concentration; provide ß-lactam therapy if MSSA; obtain repeat blood cultures every 48 h until clearance; complete appropriate treatment duration; eliminate or debride foci of infection; and obtain an echocardiogram for complicated bacteraemia. RESULTS: One hundred and seventy patients with SAB were included: 82 patients in the pre-intervention group and 88 patients in the ASP-intervention group. Overall bundle adherence to quality performance measures improved from 56.1% (46/82) in the pre-intervention group to 84.1% (74/88) in the ASP-intervention group (P < 0.001), which was associated with a reduction in 30 day readmission with SAB [9 patients (11.0%) versus 1 patient (1.1%), P = 0.008]. The 30 day mortality was numerically lower in the ASP-intervention group, but the difference was not statistically significant [16 patients (19.5%) versus 10 patients (11.4%), P = 0.2]. CONCLUSIONS: Implementation of an ASP-driven comprehensive care bundle for SAB improved adherence with performance measures and was associated with a decrease in hospital readmission for SAB.

Mortality following durable left ventricular assist device implantation by timing and type of first infection.

OBJECTIVE: Although infections are common after left ventricular assist device implantation, the relationship between timing and type of first infection with regard to mortality is less well understood. METHODS: The Society of Thoracic Surgeons Interagency Registry for Mechanically Assisted Circulatory Support patients receiving a primary left ventricular assist device from April 2012 to May 2017 were included. The primary exposure was defined 3 ways: any infection, timing of first infection (early: ≤90 days; intermediate: 91-180 days; late: >180 days), and type (ventricular assist device specific, ventricular assist device related, non-ventricular assist device). The association between first infection and all-cause mortality was estimated using Cox regression. RESULTS: The cohort included 12,957 patients at 166 centers (destination therapy: 47.4%, bridge-to-transplant: 41.2%). First infections were most often non-ventricular assist device (54.2%). Rates of first infection were highest in the early interval (10.7/100 person-months). Patients with any infection had a significantly higher adjusted hazard of death (hazard ratio, 2.63; 2.46-2.86). First infection in the intermediate interval was associated with the largest increase in adjusted hazard of death (hazard ratio, 3.26; 2.82-3.78), followed by late (hazard ratio, 3.13; 2.77-3.53) and early intervals (hazard ratio, 2.37; 2.16-2.60). Ventricular assist device-related infections were associated with the largest increase in hazard of death (hazard ratio, 3.02; 2.69-3.40), followed by ventricular assist device specific (hazard ratio, 2.92; 2.57-3.32) and non-ventricular assist device (hazard ratio, 2.42; 2.20-2.65). CONCLUSIONS: Relative to those without infection, patients with any postimplantation infection had an increased risk of death. Ventricular assist device-related infections and infections occurring in the intermediate interval were associated with the largest increase in risk of death. After left ventricular assist device implantation, infection prevention strategies should target non-ventricular assist device infections in the first 90 days, then shift to surveillance/prevention of driveline infections after 90 days.

Infections following left ventricular assist device implantation and 1-year health-related quality of life.

BACKGROUND: Left ventricular assist device (LVAD) implantation leads to substantial and sustained improvement in health-related quality of life (HRQOL) among patients. Infection following device implantation remains an important and frequent complication and adversely affects patient-reported HRQOL. METHODS: Patients in The Society of Thoracic Surgeons' Interagency Registry for Mechanically Assisted Circulatory Support receiving a primary LVAD between April 2012 to October 2016 were included. The primary exposure was one-year post-implant infection, characterized by: (1) any infection; (2) total number of infections and (3) type (LVAD-specific, LVAD-related, non-LVAD). The association between infection and the primary composite adverse outcome (defined as EuroQoL Visual Analog Scale< 65, too sick to complete the survey, or death at 1-year) was estimated using inverse probability weighting and Cox regression. RESULTS: The study cohort included 11,618 patients from 161 medical centers with 4,768 (41.0%) patients developing an infection, and 2,282 (19.6%) patients having> 1 infection during the follow up period. The adjusted odds ratio for the primary composite adverse outcome was 1.22 (95% CI, 1.19-1.24, p < 0.001) for each additional infection. Each additional infection was associated with a 3.49% greater probability of the primary composite outcome and was associated with worse performance across multiple dimensions of HRQOL as assessed by the EQ-5D for patients who survived to 1 year. CONCLUSIONS: For patients undergoing LVAD implantation, each additional infection within the first post-implantation year was associated with an incremental negative effect on survival free of impaired HRQOL.

Patient factors associated with left ventricular assist device infections: A scoping review.

Infections are widely prevalent in left ventricular assist device (LVAD) recipients and associated with adverse events including mortality and rehospitalizations. Current evidence examining factors associated with infections in this setting predominantly comprises single-center observational data. We performed a scoping review to systematically summarize all existing studies examining patient-related factors associated with infections after LVAD implantation. Studies published between 01/06 and 02/19 were identified through searching 5 bibliographic databases: PubMed, Scopus, EMBASE, CINAHL, and Web of Science Core Collection. Inclusion criteria required examination of patient-related factors associated with infections among recipients of contemporary implantable, continuous flow LVADs. Key study characteristics were extracted by four independent reviewers and current literature described narratively. All analyses took place between February 2019 and May 2021. A total of 31 studies met inclusion criteria. All included studies were observational, and most commonly focused on driveline infections (n = 17). Factors studied most commonly included body composition (n = 8), diabetes and other comorbidities (n = 8), and psychosocial/socio-economic factors (n = 6). Studies were frequently single-center with heterogeneity in definition of infectious outcomes as well as exposure variables. Patient race and sex did not correlate with infection risk. There was no consistent association noted between obesity, diabetes, or psychosocial/socio-economic factors and infections in LVAD recipients. Two studies reported a significant association between malnutrition and hypoalbuminemia and post implant infections. This review summarizes 31 studies that described patient-related factors associated with infection after LVAD implantation. Patient related comorbidities, especially body composition and diabetes, were most commonly evaluated, but were not consistently associated with infections after LVAD implantation.

Interhospital variability in health care-associated infections and payments after durable ventricular assist device implant among Medicare beneficiaries.

OBJECTIVE: The objective of this study was to investigate variations across hospitals in infection rates and associated costs, the latter reflected in 90-day Medicare payments. Despite high rates and expenditures of health care--associated infections associated with durable ventricular assist device implantation, few studies have examined interhospital variation and associated costs. METHODS: Clinical data on 8688 patients who received primary durable ventricular assist devices from July 2008 to July 2017 from the Society of Thoracic Surgeons Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) hospitals (n = 120) were merged with postimplantation 90-day Medicare claims. Terciles of hospital-specific, risk-adjusted infection rates per 100 patient-months were estimated using Intermacs and associated with Medicare payments (among 5440 Medicare beneficiaries). Primary outcomes included infections within 90 days of implantation and Medicare payments. RESULTS: There were 3982 infections identified among 27.8% (2417/8688) of patients developing an infection. The median (25th, 75th percentile) adjusted incidence of infections (per 100 patient-months) across hospitals was 14.3 (9.3, 19.5) and varied according to hospital (range, 0.0-35.6). Total Medicare payments from implantation to 90 days were 9.0% (absolute difference: $13,652) greater in high versus low infection tercile hospitals (P < .0001). The period between implantation to discharge accounted for 73.1% of the difference in payments during the implantation to 90-day period across terciles. CONCLUSIONS: Health care--associated infection rates post durable ventricular assist device implantation varied according to hospital and were associated with increased 90-day Medicare expenditures. Interventions targeting preventing infections could improve the value of durable ventricular assist device support from the societal and hospital perspectives.

Non-patient factors associated with infections in LVAD recipients: A scoping review.

BACKGROUND: Infections are the most common complication in recipients of durable left ventricular assist devices (LVAD) and are associated with increased morbidity, mortality, and expenditures. The existing literature examining factors associated with infection in LVAD recipients is limited and principally comprises single-center studies. This scoping review synthesizes all available evidence related to identifying modifiable, non-patient factors associated with infections among LVAD recipients. METHODS: Published studies were identified through searching 5 bibliographic databases: PubMed, Scopus, EMBASE, CINAHL, and Web of Science Core Collection. Inclusion criteria required examination of factors associated with infections among recipients of contemporary, implantable, continuous flow LVADs. Key study characteristics were extracted by 4 independent reviewers and current literature described narratively. The Systems Engineering Initiative for Patient Safety (SEIPS) model was used to develop a taxonomy for non-patient related factors (e.g., tasks, tools, technologies, organization, and environment) associated with infections following LVAD implantation. All analyses took place between February 2019 and May 2021. FINDINGS: A total of 43 studies met inclusion criteria. The majority of included studies were observational (n = 37), single-center (n = 29), from the U.S. (n = 38), and focused on driveline infections (n = 40). Among the 22 evaluated sub-domains of non-patient related factors, only two: increasing center experience and establishing a silicone-skin interface at the driveline exit site, were identified as consistently being associated with a lower risk of infection. CONCLUSION: This review identified 43 studies that described non-patient related factors associated with infection in LVAD recipients. Only two factors were consistently associated with lower infection risk in LVAD recipients: increasing experience and establishing a silicone-skin interface at driveline exit site. The large variability in reporting across multiple studied interventions limited the ability to discern their effectiveness.

Association Between Care Fragmentation and Total Spending After Durable Left Ventricular Device Implant: A Mediation Analysis of Health Care-Associated Infections Within a National Medicare-Society of Thoracic Surgeons Intermacs Linked Dataset.

BACKGROUND: Care fragmentation is associated with higher rates of infection after durable left ventricular assist device (LVAD) implant. Less is known about the relationship between care fragmentation and total spending, and whether this relationship is mediated by infections. METHODS: Total payments were captured from admission to 180 days post-discharge. Drawing on network theory, a measure of care fragmentation was developed based on the number of shared patients among providers (ie, anesthesiologists, cardiac surgeons, cardiologists, critical care specialists, nurse practitioners, physician assistants) caring for 4,987 Medicare beneficiaries undergoing LVAD implantation between July 2009 - April 2017. Care fragmentation was measured using average path length, which describes how efficiently information flows among network members; longer path length indicates greater fragmentation. Terciles based on the level of care fragmentation and multivariable regression were used to analyze the relationship between care fragmentation and LVAD payments and mediation analysis was used to evaluate the role of post-implant infections. RESULTS: The patient cohort was 81% male, 73% white, 11% Intermacs Profile 1 with mean (SD) age of 63.1 years (11.1). The mean (SD) level of care fragmentation in provider networks was 1.7 (0.2) and mean (SD) payment from admission to 180 days post-discharge was $246,905 ($109,872). Mean (SD) total payments at the lower, middle, and upper terciles of care fragmentation were $250,135 ($111,924), $243,288 ($109,376), and $247,290 ($108,241), respectively. In mediation analysis, the indirect effect of care fragmentation on total payments, through infections, was positive and statistically significant (ß=16032.5, p=0.008). CONCLUSIONS: Greater care fragmentation in the delivery of care surrounding durable LVAD implantation is associated with a higher incidence of infections, and consequently, higher payments for Medicare beneficiaries. Interventions to reduce care fragmentation may reduce the incidence of infections and in turn enhance the value of care for patients undergoing durable LVAD implantation.

Correction: Understanding and Addressing Variation in Health Care-Associated Infections After Durable Ventricular Assist Device Therapy: Protocol for a Mixed Methods Study.

[This corrects the article DOI: 10.2196/14701.].

Incompleteness of health-related quality of life assessments before left ventricular assist device implant: A novel quality metric.

BACKGROUND: Improved health-related quality of life (HRQOL) is an important outcome following durable left ventricular assist device (LVAD) implant. However, half of pre-implant HRQOL data are incomplete in The Society of Thoracic Surgeons' Intermacs registry. Pre-implant HRQOL incompleteness may reflect patient status or hospital resources to capture HRQOL data. We hypothesized that pre-implant HRQOL incompleteness predicts 90 day outcomes and serves as a novel quality metric. METHODS: Risk factors for pre-implant HRQOL (EQ-5D-5L visual analog scale; 12-item Kansas City Cardiomyopathy Questionnaire "KCCQ") incompleteness were examined by stepwise logistic modeling. Direct standardization method was used to calculate adjusted incompleteness rates using a mixed effects logistic model. Hospitals were dichotomized as low or high based on median adjusted incompleteness rates. Andersen-Gill models were used to associate pre-implant HRQOL adjusted incompleteness rate with adverse events within 90 day post-implant. RESULTS: The study cohort included 14,063 patients receiving a primary LVAD (4/2012-8/2017). HRQOL incompleteness at high-rate hospitals was more often due to administrative reasons (risk difference, EQ-5D: 10.1%; KCCQ-12: 11.6%) and less likely due to patient reasons (risk difference, EQ-5D: -8.9%; KCCQ-12: -11.4%). A 10% increase in the adjusted pre-implant EQ-5D incompleteness rate was significantly associated with higher risk of infection-related mortality (HR: 1.09), infection (HR: 1.05), and renal dysfunction (HR: 1.03). A 10% increase in the adjusted pre-implant KCCQ-12 incompleteness rate was significantly associated with higher risk of infection (HR: 1.04). CONCLUSIONS: Hospital adjusted pre-implant HRQOL incompleteness was predictive of 90-day post-implant outcomes and may serve as a novel quality metric.

Urinary Tract Infections: 2021 Update.

Catheter-associated urinary tract infection (CAUTI) remains one of the most prevalent, but preventable, health care-associated infections and predominantly occurs in patients with indwelling urinary catheters. Duration of urinary catheterization is the most important modifiable risk factor for development of CAUTI. Alternatives to indwelling catheters should be considered in appropriate patients. If indwelling catheterization is necessary, proper aseptic practices for catheter insertion and maintenance and use of a closed catheter collection system are essential for preventing CAUTI. The use of intervention bundles and collaboratives helps in the effective implementation of CAUTI prevention measures.

Dissemination of an Enterococcus Inc18-Like vanA plasmid associated with vancomycin-resistant Staphylococcus aureus.

Of the 9 vancomycin-resistant Staphylococcus aureus (VRSA) cases reported to date in the literature, 7 occurred in Michigan. In 5 of the 7 Michigan VRSA cases, an Inc18-like vanA plasmid was identified in the VRSA isolate and/or an associated vancomycin-resistant Enterococcus (VRE) isolate from the same patient. This plasmid may play a critical role in the emergence of VRSA. We studied the geographical distribution of the plasmid by testing 1,641 VRE isolates from three separate collections by PCR for plasmid-specific genes traA, repR, and vanA. Isolates from one collection (phase 2) were recovered from surveillance cultures collected in 17 hospitals in 13 states. All VRE isolates from 2 Michigan institutions (n = 386) and between 60 and 70 VRE isolates (n = 883) from the other hospitals were tested. Fifteen VRE isolates (3.9%) from Michigan were positive for an Inc18-like vanA plasmid (9 E. faecalis [12.5%], 3 E. faecium [1.0%], 2 E. avium, and 1 E. raffinosus). Six VRE isolates (0.6%) from outside Michigan were positive (3 E. faecalis [2.7%] and 3 E. faecium [0.4%]). Of all E. faecalis isolates tested, 6.0% were positive for the plasmid, compared to 0.6% for E. faecium and 3.0% for other spp. Fourteen of the 15 plasmid-positive isolates from Michigan had the same Tn1546 insertion site location as the VRSA-associated Inc18-like plasmid, whereas 5 of 6 plasmid-positive isolates from outside Michigan differed in this characteristic. Most plasmid-positive E. faecalis isolates demonstrated diverse patterns by PFGE, with the exception of three pairs with indistinguishable patterns, suggesting that the plasmid is mobile in nature. Although VRE isolates with the VRSA-associated Inc18-like vanA plasmid were more common in Michigan, they remain rare. Periodic surveillance of VRE isolates for the plasmid may be useful in predicting the occurrence of VRSA.

Recognition and prevention of healthcare-associated urinary tract infections in the intensive care unit.

Urinary tract infection is the most common healthcare-associated infection in the intensive care unit and predominantly occurs in patients with indwelling urinary catheters. The predominant microorganisms causing catheter-associated urinary tract infection (CAUTI) in the intensive care unit are enteric Gram-negative bacilli, enterococci, Candida species, and Pseudomonas aeruginosa. Multidrug resistance is a significant problem in urinary pathogens. Duration of catheterization is the most important risk factor for development of CAUTI. Diagnosis, particularly in the intensive care unit setting, is very difficult, as asymptomatic bacteriuria may be difficult to differentiate from symptomatic CAUTI. In general, asymptomatic bacteriuria should not be treated, and treatment of CAUTI often requires removal of the catheter along with systemic antimicrobial therapy. General strategies for prevention of CAUTI apply to all healthcare-associated infections and include measures such as adherence to hand hygiene. Targeted strategies for prevention of CAUTI include limiting the use and duration of urinary catheterization, using aseptic technique for catheter insertion, and adhering to proper catheter care.

Authorship Correction: Understanding and Addressing Variation in Health Care-Associated Infections After Durable Ventricular Assist Device Therapy: Protocol for a Mixed Methods Study.

[This corrects the article DOI: 10.2196/14701.].

Understanding and Addressing Variation in Health Care-Associated Infections After Durable Ventricular Assist Device Therapy: Protocol for a Mixed Methods Study.

BACKGROUND: Durable ventricular assist device (VAD) therapy is reserved for patients with advanced heart failure who have a poor estimated 1-year survival. However, despite highly protocolized management processes, patients are at a unique risk for developing a health care-associated infection (HAI). Few studies have examined optimal strategies for HAI prevention after durable VAD implantation, despite variability in rates across centers and their impact on short- and long-term outcomes. OBJECTIVE: The objective of this study is to develop recommendations for preventing the most significant HAIs after durable VAD implantation. The study has 3 specific aims: (1) identify determinants of center-level variability in HAI rates, (2) develop comprehensive understanding of barriers and facilitators for achieving low center-level HAI rates, and (3) develop and disseminate a best practices toolkit for preventing HAIs that accommodates various center contexts. METHODS: This is a sequential mixed methods study starting with a cross-sectional assessment of current practices. To address aim 1, we will conduct (1) a systematic review of HAI prevention studies and (2) in-depth quantitative analyses using administrative claims, in-depth clinical data, and organizational surveys of VAD centers. For aim 2, we will apply a mixed methods patient tracer assessment framework to conduct semistructured interviews, field observations, and document analysis informed by findings from aim 1 at 5 high-performing (ie, low HAIs) and 5 low-performing (ie, high HAI) centers, which will be examined using a mixed methods case series analysis. For aim 3, we will build upon the findings from the previous aims to develop and field test an HAI preventive toolkit, acquire stakeholder input at an annual cardiac surgical conference, disseminate the final version to VAD centers nationwide, and conduct follow-up surveys to assess the toolkit's adoption. RESULTS: The project was funded by the Agency for Healthcare Research and Quality in 2018 and enrollment for the overall project is ongoing. Data analysis is currently under way and the first results are expected to be submitted for publication in 2019. CONCLUSIONS: This mixed methods study seeks to quantitatively assess the determinants of HAIs across clinical centers and qualitatively identify the context-specific facilitators and barriers for attaining low HAI rates. The mixed data findings will be used to develop and disseminate a stakeholder-acceptable toolkit of evidence-based HAI prevention recommendations that will accommodate the specific contexts and needs of VAD centers. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/14701.

Detection of the Klebsiella pneumoniae carbapenemase type 2 Carbapenem-hydrolyzing enzyme in clinical isolates of Citrobacter freundii and K. oxytoca carrying a common plasmid.

The Klebsiella pneumoniae carbapenemase (KPC) was detected in carbapenem-resistant isolates of Citrobacter freundii and Klebsiella oxytoca recovered from different patients in a Michigan hospital. Restriction analysis and hybridization with a KPC-specific probe showed the bla(KPC-2) genes of these two genera of the family Enterobacteriaceae are carried on a common plasmid.

Urinary Catheter-Associated Infections.

Catheter-associated urinary tract infection remains one of the most prevalent, yet preventable, health care-associated infections. General prevention strategies include strict adherence to hand hygiene and antimicrobial stewardship. Duration of urinary catheterization is the most important modifiable risk factor. Targeted prevention strategies include limiting urinary catheter use; physician reminder systems, nurse-initiated discontinuation protocols, and automatic stop orders have successfully decreased catheter duration. Alternatives should be considered. If catheterization is necessary, proper aseptic practices for insertion and maintenance and closed catheter collection systems are essential for prevention. The use of bladder bundles and collaboratives aids in the effective implementation of prevention measures.

Collaborative Quality Improvement Reduces Postoperative Pneumonia After Isolated Coronary Artery Bypass Grafting Surgery.

BACKGROUND: To date, studies evaluating outcome improvements associated with participation in physician-led collaboratives have been limited by the absence of a contemporaneous control group. We examined post cardiac surgery pneumonia rates associated with participation in a statewide, quality improvement collaborative relative to a national physician reporting program. METHODS AND RESULTS: We evaluated 911 754 coronary artery bypass operations (July 1, 2011, to June 30, 2017) performed across 1198 hospitals participating in a voluntary national physician reporting program (Society of Thoracic Surgeons [STS]), including 33 that participated in a Michigan-based collaborative (MI-Collaborative). Unlike STS hospitals not participating in the MI-Collaborative (i.e., STSnonMI) that solely received blinded reports, MI-Collaborative hospitals received a multi-faceted intervention starting November 2012 (quarterly in-person meetings showcasing unblinded data, webinars, site visits). Eighteen of the MI-Collaborative hospitals received additional support to implement recommended pneumonia prevention practices ("MI-CollaborativePlus"), whereas 15 did not ("MI-CollaborativeOnly"). We evaluated rates of postoperative pneumonia, adjusting for patient mix and hospital effects. Baseline patient characteristics were qualitatively similar between groups and time. During the preintervention period (Q3/2011 through Q3/2012), there was no statistically significant difference in the adjusted odds of pneumonia for STS hospitals participating in the MI-Collaborative compared to the STS non-MI hospitals. However, during the intervention period (Q4/2012 through Q2/2017), there was a significant 2% reduction per quarter in the adjusted odds of pneumonia for MI-Collaborative hospitals (n=33) relative to the STS-nonMI hospitals. There was a significant 3% per quarter reduction in the adjusted odds of pneumonia for the MI-CollaborativeOnly (n=15) hospitals relative to the STS-nonMI hospitals. Over the course of the overall study period, the STS-nonMI hospitals had a 1.96% reduction in risk-adjusted pneumonia (pre- vs. intervention periods), which was less than the MI-Collaborative (3.23%, P=0.011). Over the same time period, the MI-CollaborativePlus (n=18) reduced adjusted pneumonia rates by 10.29%, P=0.001. CONCLUSIONS: Participation in a physician-led collaborative was associated with significant reductions in pneumonia relative to a national quality reporting program. Interventions including collaborative learning may yield superior outcomes relative to solely using physician feedback reporting. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02068716.

Mycobacterium neoaurum bloodstream infection: report of 4 cases and review of the literature.

We describe a cluster of 4 bloodstream infections with Mycobacterium neoaurum and 5 additional cases from the literature. Infections occurred mainly in immunocompromised hosts who had central venous catheters. Fever was universal at presentation, but local signs of inflammation were rare. Combination antimicrobial therapy and catheter removal resulted in clinical cure.

Review of clinical trials of skin antiseptic agents used to reduce blood culture contamination.

False-positive blood culture results may lead to prolonged hospitalization, inappropriate antibiotic administration, and increased healthcare costs. We conducted a review of the literature to assess the effect of skin antiseptic agents on the rate of false-positive blood culture results. We found no clear evidence to suggest which antiseptic should be used to prevent false-positive results. Studies suggest, however, a possible benefit from the use of prepackaged skin antiseptic kits and alcohol-containing antiseptics.

Ventilator-associated pneumonia in the home care setting.

OBJECTIVE: To describe the rate of infection, associated organisms, and potential risk factors for ventilator-associated pneumonia (VAP) in patients receiving mechanical ventilation at home. DESIGN: Retrospective cohort study. SETTING: University-affiliated home care service. PATIENTS: Patients receiving mechanical ventilation at home from June 1995 through December 2001. RESULTS: Fifty-seven patients underwent ventilation at home for a total of 50,762 ventilator-days (mean +/- SD, 890.6 +/- 644.43 days; range, 76-2,458 days). Seventy-nine episodes of VAP occurred in 27 patients (rate, 1.55 episodes per 1,000 ventilator-days). The first episode of VAP occurred after a mean (+/-SD) of 245 +/- 318.07 ventilator-days. VAP was most common during the first 500 days of ventilation. Rates of VAP were higher among patients who required ventilation for longer daily durations, compared with those who required it for shorter daily durations. There was no association of VAP with age, sex, underlying disease, reason for ventilation, antacid therapy, or steroid use. Microorganisms isolated from 33 episodes of VAP with available culture results included Pseudomonas species (17 isolates), Staphylococcus aureus (11), Serratia species (7), and Stenotrophomonas species (5). Eight patients died during the study; no deaths were attributed to pneumonia. CONCLUSIONS: Although the organisms associated with VAP in the home setting are similar to those associated with hospital-acquired VAP, the incidence and mortality is much lower in the home care setting. Interventions to reduce the risk of VAP among patients receiving home care should be focused on patients who require ventilation for longer daily durations or who are new to receiving mechanical ventilation at home.