Colistin Monotherapy versus Combination Therapy for Carbapenem-Resistant Organisms.

BACKGROUND: Pneumonia and bloodstream infections (BSI) due to extensively drug-resistant (XDR) Acinetobacter baumannii, XDR Pseudomonas aeruginosa, and carbapenem-resistant Enterobacterales (CRE) are associated with high mortality rates, and therapeutic options remain limited. This trial assessed whether combination therapy with colistin and meropenem was superior to colistin monotherapy for the treatment of these infections. METHODS: The OVERCOME (Colistin Monotherapy versus Combination Therapy) trial was an international, randomized, double-blind, placebo-controlled trial. We randomly assigned participants to receive colistin (5 mg/kg once followed by 1.67 mg/kg every 8 hours) in combination with either meropenem (1000 mg every 8 hours) or matching placebo for the treatment of pneumonia and/or BSI caused by XDR A. baumannii, XDR P. aeruginosa, or CRE. The primary outcome was 28-day mortality, and secondary outcomes included clinical failure and microbiologic cure. RESULTS: Between 2012 and 2020, a total of 464 participants were randomly assigned to treatment, and 423 eligible patients comprised the modified intention-to-treat population. A. baumannii was the predominant trial pathogen (78%) and pneumonia the most common index infection (70%). Most patients were in the intensive care unit at the time of enrollment (69%). There was no difference in mortality (43 vs. 37%; P=0.17), clinical failure (65 vs. 58%; difference, 6.8 percentage points; 95% confidence interval [CI], -3.1 to 16.6), microbiologic cure (65 vs. 60%; difference, 4.8 percentage points; 95% CI, -5.6 to 15.2), or adverse events (acute kidney injury, 52 vs. 49% [P=0.55]; hypersensitivity reaction, 1 vs. 3% [P=0.22]; and neurotoxicity, 5 vs. 2% [P=0.29]) between patients receiving monotherapy and combination therapy, respectively. CONCLUSIONS: Combination therapy with colistin and meropenem was not superior to colistin monotherapy for the treatment of pneumonia or BSI caused by these pathogens. (Funded by the National Institute of Allergy and Infectious Diseases, Division of Microbiology and Infectious Diseases protocol 10-0065; ClinicalTrials.gov number, NCT01597973.).

Strongyloides stercoralis hyperinfection syndrome: a known entity in an unknown provenance.

A 49-year-old man was admitted with altered mental status, high-grade fevers, tachycardia and leucocytosis. Cerebrospinal fluid (CSF) was purulent with a markedly elevated nucleated cell count with neutrophilic predominance, elevated protein and low glucose. CSF gram stain was negative. Patient received vancomycin, cefepime, ampicillin and acyclovir for presumed meningitis. He was intubated for protection of airway and underwent bronchoscopy. Microscopic examination of the bronchoalveolar lavage noted Strongyloides filariform larvae. Ivermectin was prescribed. Other laboratory tests showed a positive HIV test associated with a low CD4 count. Stool ova and parasite also revealed Strongyloides and repeat lumbar puncture identified larvae in the CSF. Albendazole was added for adjunctive therapy. However, the patient suffered a large intraparenchymal haemorrhage extending into the ventricles and he expired 36 days after admission.

Predictive Value of Sequential Organ Failure Assessment Score across Patients with and without COVID-19 Infection.

Rationale: Sequential organ failure assessment (SOFA) scores are commonly used in crisis standards of care policies to assist in resource allocation. The relative predictive value of SOFA by coronavirus disease (COVID-19) infection status and among racial and ethnic subgroups within patients infected with COVID-19 is unknown. Objectives: To evaluate the accuracy and calibration of SOFA in predicting hospital mortality by COVID-19 infection status and across racial and ethnic subgroups. Methods: We performed a retrospective cohort study of adult admissions to the University of Miami Hospital and Clinics inpatient wards (July 1, 2020-April 1, 2021). We primarily considered maximum SOFA within 48 hours of hospitalization. We assessed accuracy using the area under the receiver operating characteristic curve (AUROC) and created calibration belts. Considered subgroups were defined by COVID-19 infection status (by severe acute respiratory syndrome coronavirus 2 polymerase chain reaction testing) and prevalent racial and ethnic minorities. Comparisons across subgroups were made with DeLong testing for discriminative accuracy and visualization of calibration belts. Results: Our primary cohort consisted of 20,045 hospitalizations, of which 1,894 (9.5%) were COVID-19 positive. SOFA was similarly accurate for COVID-19-positive (AUROC, 0.835) and COVID-19-negative (AUROC, 0.810; P = 0.15) admissions but was slightly better calibrated in patients who were positive for COVID-19. For those with critical illness, maximum SOFA score accuracy at critical illness onset also did not differ by COVID-19 status (AUROC, COVID-19 positive vs. negative: intensive care unit admissions, 0.751 vs. 0.775; P = 0.46; mechanically ventilated, 0.713 vs. 0.792, P = 0.13), and calibration was again better for patients positive for COVID-19. Among patients with COVID-19, SOFA accuracy was similar between the non-Hispanic White population (AUROC, 0.894) and racial and ethnic minorities (Hispanic White population: AUROC, 0.824 [P vs. non-Hispanic White = 0.05]; non-Hispanic Black population: AUROC, 0.800 [P = 0.12]; Hispanic Black population: AUROC, 0.948 [P = 0.31]). This similar accuracy was also found for those without COVID-19 (non-Hispanic White population: AUROC, 0.829; Hispanic White population: AUROC, 0.811 [P = 0.37]; Hispanic Black population: AUROC, 0.828 [P = 0.97]; non-Hispanic Black population: AUROC, 0.867 [P = 0.46]). SOFA was well calibrated for all racial and ethnic groups with COVID-19 but estimated mortality more variably and performed less well across races and ethnicities without COVID-19. Conclusions: SOFA accuracy does not differ by COVID-19 status and is similar among racial and ethnic groups both with and without COVID-19. Calibration is better for COVID-19-infected patients and, among those without COVID-19, varies by race and ethnicity.

Assessment of Disparities Associated With a Crisis Standards of Care Resource Allocation Algorithm for Patients in 2 US Hospitals During the COVID-19 Pandemic.

Importance: Significant concern has been raised that crisis standards of care policies aimed at guiding resource allocation may be biased against people based on race/ethnicity. Objective: To evaluate whether unanticipated disparities by race or ethnicity arise from a single institution's resource allocation policy. Design, Setting, and Participants: This cohort study included adults (aged ≥18 years) who were cared for on a coronavirus disease 2019 (COVID-19) ward or in a monitored unit requiring invasive or noninvasive ventilation or high-flow nasal cannula between May 26 and July 14, 2020, at 2 academic hospitals in Miami, Florida. Exposures: Race (ie, White, Black, Asian, multiracial) and ethnicity (ie, non-Hispanic, Hispanic). Main Outcomes and Measures: The primary outcome was based on a resource allocation priority score (range, 1-8, with 1 indicating highest and 8 indicating lowest priority) that was assigned daily based on both estimated short-term (using Sequential Organ Failure Assessment score) and longer-term (using comorbidities) mortality. There were 2 coprimary outcomes: maximum and minimum score for each patient over all eligible patient-days. Standard summary statistics were used to describe the cohort, and multivariable Poisson regression was used to identify associations of race and ethnicity with each outcome. Results: The cohort consisted of 5613 patient-days of data from 1127 patients (median [interquartile range {IQR}] age, 62.7 [51.7-73.7]; 607 [53.9%] men). Of these, 711 (63.1%) were White patients, 323 (28.7%) were Black patients, 8 (0.7%) were Asian patients, and 31 (2.8%) were multiracial patients; 480 (42.6%) were non-Hispanic patients, and 611 (54.2%) were Hispanic patients. The median (IQR) maximum priority score for the cohort was 3 (1-4); the median (IQR) minimum score was 2 (1-3). After adjustment, there was no association of race with maximum priority score using White patients as the reference group (Black patients: incidence rate ratio [IRR], 1.00; 95% CI, 0.89-1.12; Asian patients: IRR, 0.95; 95% CI. 0.62-1.45; multiracial patients: IRR, 0.93; 95% CI, 0.72-1.19) or of ethnicity using non-Hispanic patients as the reference group (Hispanic patients: IRR, 0.98; 95% CI, 0.88-1.10); similarly, no association was found with minimum score for race, again with White patients as the reference group (Black patients: IRR, 1.01; 95% CI, 0.90-1.14; Asian patients: IRR, 0.96; 95% CI, 0.62-1.49; multiracial patients: IRR, 0.81; 95% CI, 0.61-1.07) or ethnicity, again with non-Hispanic patients as the reference group (Hispanic patients: IRR, 1.00; 95% CI, 0.89-1.13). Conclusions and Relevance: In this cohort study of adult patients admitted to a COVID-19 unit at 2 US hospitals, there was no association of race or ethnicity with the priority score underpinning the resource allocation policy. Despite this finding, any policy to guide altered standards of care during a crisis should be monitored to ensure equitable distribution of resources.

Defining standards of CARE for invasive fungal diseases in the ICU.

The aim of this article is to review the current recommendations for the diagnosis and treatment of invasive fungal infection in the ICU setting and to explore whether there are standards of care for this patient population. The text focuses mainly on the two most common invasive fungal diseases that afflict non-neutropenic patients: candidaemia and invasive candidosis (IC), and invasive pulmonary aspergillosis (IPA).

Nonstandard do-not-resuscitate orders.

PURPOSE OF REVIEW: Tattoos and medallions are examples of nonstandard do-not-resuscitate (DNR) orders that some people use to convey end-of-life wishes. These DNR orders are neither universally accepted nor understood for reasons discussed within this manuscript. RECENT FINDINGS: Studies show both providers and patients confuse the meaning and implication of DNR orders. In the United States, out-of-hospital DNR orders are legislated at the state level. Most states standardized out-of-hospital DNR orders so caregivers can immediately recognize and accept the order and act on its behalf. These out-of-hospital orders are complicated by the need to be printed on paper that does not always accompany the individual. Oregon created an online system whereby individuals recorded their end-of-life wishes that medical personnel can access with an Internet connection. This system improved communication of end-of-life wishes in patients who selected comfort care only. SUMMARY: To improve conveyance of an individual's wishes for end-of-life care, the authors discuss nationwide adoption of Oregon's online registry where a person's account could comprehensively document end-of-life wishes, be universally available in all healthcare institutions, and be searchable by common patient identifiers. Facial recognition software could identify unconscious patients who present without identification.

Intensive care medicine research agenda on invasive fungal infection in critically ill patients.

PURPOSE: To describe concisely the current standards of care, major recent advances, common beliefs that have been contradicted by recent trials, areas of uncertainty, and clinical studies that need to be performed over the next decade and their expected outcomes with regard to Candida and Aspergillus infections in non-neutropenic patients in the ICU setting. METHODS: A systematic review of the medical literature taking account of national and international guidelines and expert opinion. RESULTS: Severe invasive fungal infections (IFIs) are becoming increasingly frequent in critically ill patients. Approximately 80% of IFIs are due to Candida spp. and 0.3-19% to Aspergillus spp. Recent observations emphasize the necessity of building a worldwide sentinel network to monitor the emergence of new fungal species and changes in susceptibility. Robust data on the attributable mortality are essential for the design of clinical studies with mortality endpoints. Although early antifungal therapy for Candida has been recommended in patients with risk factors, sepsis of unknown cause, and positive Candida serum biomarkers [ß-1 â†’ 3-D-glucan (BDG) and Candida albicans germ tube antibody (CAGTA)], its usefulness and influence on outcome need to be confirmed. Future studies may specifically address the optimal diagnostic and therapeutic strategies for patients with abdominal candidiasis. Better knowledge of the pharmacokinetics of antifungal molecules and tissue penetration is a key issue for intensivists. Regarding invasive aspergillosis, further investigation is needed to determine its incidence in the ICU, its relationship with influenza outbreaks, the clinical impact of rapid diagnosis, and the significance of combination treatment. CONCLUSIONS: Fundamental questions regarding IFI have to be addressed over the next decade. The clinical studies described in this research agenda should provide a template and set priorities for the clinical investigations that need to be performed.

Carbapenem-Resistant Acinetobacter baumannii: Concomitant Contamination of Air and Environmental Surfaces.

OBJECTIVE To concomitantly determine the differential degrees of air and environmental contamination by Acinetobacter baumannii based on anatomic source of colonization and type of ICU layout (single-occupancy vs open layout). DESIGN Longitudinal prospective surveillance study of air and environmental surfaces in patient rooms. SETTING A 1,500-bed public teaching hospital in Miami, Florida. PATIENTS Consecutive A. baumannii-colonized patients admitted to our ICUs between October 2013 and February 2014. METHODS Air and environmental surfaces of the rooms of A. baumannii-colonized patients were sampled daily for up to 10 days. Pulsed-field gel electrophoresis (PFGE) was used to type and match the matching air, environmental, and clinical A. baumannii isolates. RESULTS A total of 25 A. baumannii-colonized patients were identified during the study period; 17 were colonized in the respiratory tract and 8 were colonized in the rectum. In rooms with rectally colonized patients, 38.3% of air samples were positive for A. baumannii; in rooms of patients with respiratory colonization, 13.1% of air samples were positive (P=.0001). In rooms with rectally colonized patients, 15.5% of environmental samples were positive for A. baumannii; in rooms of patients with respiratory colonization, 9.5% of environmental samples were positive (P=.02). The rates of air contamination in the open-layout and single-occupancy ICUs were 17.9% and 21.8%, respectively (P=.5). Environmental surfaces were positive in 9.5% of instances in open-layout ICUs versus 13.4% in single-occupancy ICUs (P=.09). CONCLUSIONS Air and environmental surface contaminations were significantly greater among rectally colonized patients; however, ICU layout did not influence the rate of contamination. Infect Control Hosp Epidemiol 2016;37:777-781.

Stewart-Treves Syndrome: A Case Report and Review of the Literature.

The Stewart-Treves syndrome is a rare and deadly entity, which is defined as angiosarcoma arising in the setting of chronic lymphedema. It typically presents in women who develop lymphedema in the upper extremity secondary to axillary lymph node dissection for breast cancer surgery. It is extremely uncommon in the lower extremities as a result of idiopathic chronic lymphedema. Here, we present the case of a 63-year-old female patient with idiopathic chronic lymphedema of the lower extremities having morbid obesity (BMI 82.6) and multiple comorbidities. She developed multiple confluent, hemorrhagic and necrotic elevated purple-black papules in the lower extremities, for which the initial diagnosis was cellulitis. Because there was no improvement with antibiotics, a lower extremity ultrasound and biopsy was performed which showed multiple masses in the left inner upper calf with solid and cystic components. The pathology results of the punch biopsies were consistent with angiosarcoma. Immunohistochemical studies revealed positivity for CD31, FLI-1, and a high Ki-67 proliferation rate. Because of the patient's weight and medical comorbidities, no further extensive diagnostic tests were performed to detect metastatic disease, and because of contraindications, no further medical treatment was provided. The patient subsequently died 1 month after diagnosis.

Contamination of Ambient Air with Acinetobacter baumannii on Consecutive Inpatient Days.

Acinetobacter-positive patients had their ambient air tested for up to 10 consecutive days. The air was Acinetobacter positive for an average of 21% of the days; the rate of contamination was higher among patients colonized in the rectum than in the airways (relative risk [RR], 2.35; P = 0.006). Of the 6 air/clinical isolate pairs available, 4 pairs were closely related according to rep-PCR results.

Impact of universal gowning and gloving on health care worker clothing contamination.

OBJECTIVE: To determine whether gowning and gloving for all patient care reduces contamination of healthcare worker (HCW) clothing, compared to usual practice. DESIGN: Cross-sectional surveys. SETTING: Five study sites were recruited from intensive care units (ICUs) randomized to the intervention arm of the Benefits of Universal Gown and Glove (BUGG) study. PARTICIPANTS: All HCWs performing direct patient care in the study ICUs were eligible to participate. METHODS: Surveys were performed first during the BUGG intervention study period (July-September 2012) with universal gowning/gloving and again after BUGG study conclusion (October-December 2012), with resumption of usual care. During each phase, HCW clothing was sampled at the beginning and near the end of each shift. Cultures were performed using broth enrichment followed by selective media. Acquisition was defined as having a negative clothing culture for samples taken at the beginning of a shift and positive clothing culture at for samples taken at the end of the shift. RESULTS: A total of 348 HCWs participated (21-92 per site), including 179 (51%) during the universal gowning/gloving phase. Overall, 51 (15%) HCWs acquired commonly pathogenic bacteria on their clothing: 13 (7.1%) HCWs acquired bacteria during universal gowning/gloving, and 38 (23%) HCWs acquired bacteria during usual care (odds ratio [OR], 0.3; 95% confidence interval [CI], 0.2-0.6). Pathogens identified included S. aureus (25 species, including 7 methicillin-resistant S. aureus [MRSA]), Enterococcus spp. (25, including 1 vancomycin-resistant Enterococcus [VRE]), Pseudomonas spp. (4), Acinetobacter spp. (4), and Klebsiella (2). CONCLUSION: Nearly 25% of HCWs practicing usual care (gowning and gloving only for patients with known resistant bacteria) contaminate their clothing during their shift. This contamination was reduced by 70% by gowning and gloving for all patient interactions.

Effect of chlorhexidine bathing and other infection control practices on the Benefits of Universal Glove and Gown (BUGG) trial: a subgroup analysis.

We report the results of a subgroup analysis of the Benefits of Universal Glove and Gown trial. In 20 intensive care units, the reduction in acquisition of methicillin-resistant Staphylococcus aureus observed in this trial was observed in units also using chlorhexidine bathing and in those that previously performed active surveillance.

Higher clinical success in patients with ventilator-associated pneumonia due to methicillin-resistant Staphylococcus aureus treated with linezolid compared with vancomycin: results from the IMPACT-HAP study.

INTRODUCTION: Controversy exists regarding optimal treatment for ventilator-associated pneumonia (VAP) due to methicillin-resistant Staphylococcus aureus (MRSA). The primary objective of this study was to compare clinical success of linezolid versus vancomycin for the treatment of patients with MRSA VAP. METHODS: This was a multicenter, retrospective, observational study of patients with VAP (defined according to Centers for Disease Control and Prevention criteria) due to MRSA who were treated with linezolid or vancomycin. MRSA VAP was considered when MRSA was isolated from a tracheal aspirate or bronchoalveolar lavage. Clinical success was evaluated by assessing improvement or resolution of signs and symptoms of VAP by day 14. After matching on confounding factors, logistic regression models were used to determine if an association existed between treatment arm and clinical success. RESULTS: A total of 188 patients were evaluated (101 treated with linezolid and 87 with vancomycin). The mean ± standard deviation Acute Physiology and Chronic Health Evaluation (APACHE) II score was 21 ± 11 for linezolid- and 19 ± 9 for vancomycin-treated patients (P = 0.041). Clinical success occurred in 85% of linezolid-treated patients compared with 69% of vancomycin-treated patients (P = 0.009). After adjusting for confounding factors, linezolid-treated patients were 24% more likely to experience clinical success than vancomycin-treated patients (P = 0.018). CONCLUSIONS: This study adds to the evidence indicating that patients with MRSA VAP who are treated with linezolid are more likely to respond favorably compared with patients treated with vancomycin.

Differential environmental contamination with Acinetobacter baumannii based on the anatomic source of colonization.

BACKGROUND: Acinetobacter baumannii is a pathogen of importance worldwide. METHODS: From January 2011 until January 2012, environmental and surveillance cultures were collected from patients admitted to our intensive care units (ICUs). Surveillance cultures were obtained on admission to the ICU and weekly thereafter. Environmental cultures of high-touch surfaces were performed on an alternating basis every week. A room was designated as contaminated if at least 1 object was positive for carbapenem-resistant A baumannii. We only evaluated the rooms belonging to patients who tested positive for Acinetobacter infection. RESULTS: Five hundred eighty-six rooms were cultured across the 5 ICUs surveyed, of which 134 (22.9%) had patients who tested positive for infection with Acinetobacter. Among patients colonized in the rectum, the odds of having bed rails contaminated with A baumannii were 2.55 times the odds of those with only respiratory colonization (P = .03). The odds of having intravenous pumps contaminated with A baumannii among patients with only respiratory colonization were 2.72 times the odds of contamination among patients colonized in the rectum (P = .03). CONCLUSIONS: There was a significant difference in the degree of contamination of bedrails and intravenous pumps based on the occupant's anatomic source of A baumannii infection.

Control of a two-decade endemic situation with carbapenem-resistant Acinetobacter baumannii: electronic dissemination of a bundle of interventions.

BACKGROUND: Our institution continued to experience a hyperendemic situation with carbapenem-resistant Acinetobacter baumannii despite a bundle of interventions. We aim to describe the effect of the subsequent implementation of electronic dissemination of the weekly findings of a bundle of interventions. METHODS: This was a quasiexperimental study performed at a 1,500-bed, public, teaching hospital. From January 2011 to March 2012, weekly electronic communications were sent to the hospital leadership and intensive care units (ICUs). These communications aimed to describe, interpret, and package the findings of the previous week's active surveillance cultures, environmental cultures, environmental disinfection, and hand cultures. Additionally, action plans based on these findings were shared with recipients. RESULTS: During 42 months and 1,103,900 patient-days, we detected 438 new acquisitions of carbapenem-resistant A baumannii. Hospital wide, the rate of acquisition decreased from 5.13 ± 0.39 to 1.93 ± 0.23 per 10,000 patient-days, during the baseline and postintervention periods, respectively (P < .0001). This effect was also observed in the medical and trauma ICUs, with decreased rates from 67.15 ± 10.56 to 17.4 ± 4.6 (P < .0001) and from 55.9 ± 8.95 to 14.71 ± 4.45 (P = .0004), respectively. CONCLUSION: Weekly and systematic dissemination of the findings of a bundle of interventions was successful in decreasing the rates of carbapenem-resistant A baumannii across a large public hospital.

Environmental exposure to carbapenem-resistant Acinetobacter baumannii as a risk factor for patient acquisition of A. baumannii.

We aimed to determine the association between environmental exposure to carbapenem-resistant Acinetobacter baumannii and the subsequent risk of acquiring this organism. Patients exposed to a contaminated hospital environment had 2.77 times the risk of acquiring carbapenem-resistant A. baumannii than did unexposed patients (relative risk, 2.77 [95% confidence interval, 1.50-5.13]; P = .002).

Evaluation of an early step-down strategy from intravenous anidulafungin to oral azole therapy for the treatment of candidemia and other forms of invasive candidiasis: results from an open-label trial.

BACKGROUND: Hospitalized patients are at increased risk for candidemia and invasive candidiasis (C/IC). Improved therapeutic regimens with enhanced clinical and pharmacoeconomic outcomes utilizing existing antifungal agents are still needed. METHODS: An open-label, non-comparative study evaluated an intravenous (i.v.) to oral step-down strategy. Patients with C/IC were treated with i.v. anidulafungin and after 5 days of i.v. therapy had the option to step-down to oral azole therapy (fluconazole or voriconazole) if they met prespecified criteria. The primary endpoint was the global response rate (clinical + microbiological) at end of treatment (EOT) in the modified intent-to-treat (MITT) population (at least one dose of anidulafungin plus positive Candida within 96 hours of study entry). Secondary endpoints included efficacy at other time points and in predefined patient subpopulations. Patients who stepped down early (≤ 7 days' anidulafungin) were identified as the "early switch" subpopulation. RESULTS: In total, 282 patients were enrolled, of whom 250 were included in the MITT population. The MITT global response rate at EOT was 83.7% (95% confidence interval, 78.7-88.8). Global response rates at all time points were generally similar in the early switch subpopulation compared with the MITT population. Global response rates were also similar across multiple Candida species, including C. albicans, C. glabrata, and C. parapsilosis. The most common treatment-related adverse events were nausea and vomiting (four patients each). CONCLUSIONS: A short course of i.v. anidulafungin, followed by early step-down to oral azole therapy, is an effective and well-tolerated approach for the treatment of C/IC. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00496197.

A comparison of microbiology and demographics among patients with healthcare-associated, hospital-acquired, and ventilator-associated pneumonia: a retrospective analysis of 1184 patients from a large, international study.

BACKGROUND: Acceptance of healthcare-associated pneumonia (HCAP) as an entity and the associated risk of infection by potentially multidrug-resistant (MDR) organisms such as methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas and Acinetobacter have been debated. We therefore compared patients with HCAP, hospital-acquired pneumonia (HAP), and ventilator-associated pneumonia (VAP) enrolled in a trial comparing linezolid with vancomycin for treatment of pneumonia. METHODS: The analysis included all patients who received study drug. HCAP was defined as pneumonia occurring < 48 hours into hospitalization and acquired in a long-term care, subacute, or intermediate health care facility; following recent hospitalization; or after chronic dialysis. RESULTS: Data from 1184 patients (HCAP = 199, HAP = 379, VAP = 606) were analyzed. Compared with HAP and VAP patients, those with HCAP were older, had slightly higher severity scores, and were more likely to have comorbidities. Pseudomonas aeruginosa was the most common gram-negative organism isolated in all pneumonia classes [HCAP, 22/199 (11.1%); HAP, 28/379 (7.4%); VAP, 57/606 (9.4%); p = 0.311]. Acinetobacter spp. were also found with similar frequencies across pneumonia groups. To address potential enrollment bias toward patients with MRSA pneumonia, we grouped patients by presence or absence of MRSA and found little difference in frequencies of Pseudomonas and Acinetobacter. CONCLUSIONS: In this population of pneumonia patients, the frequencies of MDR gram-negative pathogens were similar among patients with HCAP, HAP, or VAP. Our data support inclusion of HCAP within nosocomial pneumonia guidelines and the recommendation that empiric antibiotic regimens for HCAP should be similar to those for HAP and VAP.