Prediction of ventilator-associated pneumonia outcomes according to the early microbiological response: a retrospective observational study.

BACKGROUND: Ventilator-associated pneumonia (VAP) is a leading infectious cause of morbidity in critically ill patients, yet current guidelines offer no indications for follow-up cultures. We aimed to evaluate the role of follow-up cultures and microbiological response 3 days after diagnosing VAP as predictors of short- and long-term outcomes. METHODS: We performed a retrospective analysis of a cohort prospectively collected from 2004 to 2017. VAP was diagnosed based on clinical, radiographical and microbiological criteria. For microbiological identification, a tracheobronchial aspirate was performed at diagnosis and repeated after 72 h. We defined three groups when comparing the two tracheobronchial aspirate results: persistence, superinfection and eradication of causative pathogens. RESULTS: 157 patients were enrolled in the study, among whom microbiological persistence, superinfection or eradication was present in 67 (48%), 25 (16%) and 65 (41%), respectively, after 72 h. Those with superinfection had the highest mortalities in the intensive care unit (p=0.015) and at 90 days (p=0.036), while also having the fewest ventilator-free days (p=0.019). Multivariable analysis revealed shock at VAP diagnosis (OR 3.43, 95% CI 1.25-9.40), Staphylococcus aureus isolation at VAP diagnosis (OR 2.87, 95% CI 1.06-7.75) and hypothermia at VAP diagnosis (OR 0.67, 95% CI 0.48-0.95, per +1°C) to be associated with superinfection. CONCLUSIONS: Our retrospective analysis suggests that VAP short- and long-term outcomes may be associated with superinfection in follow-up cultures. Follow-up cultures may help guide antibiotic therapy and its duration. Further prospective studies are necessary to verify our findings.

Impact on in-hospital mortality of ceftaroline versus standard of care in community-acquired pneumonia: a propensity-matched analysis.

The purpose of this study is to evaluate the in-hospital mortality of community-acquired pneumonia (CAP) treated with ceftaroline in comparison with standard therapy. This was a retrospective observational study in two centers. Hospitalized patients with CAP were grouped according to the empiric regimen (ceftaroline versus standard therapy) and analyzed using a propensity score matching (PSM) method to reduce confounding factors. Out of the 6981 patients enrolled, 5640 met the inclusion criteria, and 89 of these received ceftaroline. After PSM, 78 patients were considered in the ceftaroline group (cases) and 78 in the standard group (controls). Ceftaroline was mainly prescribed in cases with severe pneumonia (67% vs. 56%, p = 0.215) with high suspicion of Staphylococcus aureus infection (9% vs. 0%, p = 0.026). Cases had a longer length of hospital stay (13 days vs. 10 days, p = 0.007), while an increased risk of in-hospital mortality was observed in the control group compared to the case group (13% vs. 21%, HR 0.41; 95% CI 0.18 to 0.62, p = 0.003). The empiric use of ceftaroline in hospitalized patients with severe CAP was associated with a decreased risk of in-hospital mortality.

The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients.

BACKGROUND: Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. METHODS: Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. RESULTS: Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). CONCLUSIONS: Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation.

Association between physical activity and risk of hospitalisation in bronchiectasis.

BACKGROUND: Patients with bronchiectasis have a less active lifestyle than healthy peers, but the association with hospital admission has not been explored. The aim of this study was to investigate the association between 1) any physical activity variable; and 2) sedentary time, with hospitalisation due to exacerbation in adults with bronchiectasis. METHODS: In this prospective observational study, baseline lung function, quality of life, exercise tolerance, severity of bronchiectasis and physical activity were recorded. Physical activity was objectively assessed over a week using a SenseWear armband and the results were expressed in steps·day-1 and sedentary time. Number of hospitalisations due to a bronchiectasis exacerbation and time to first event were recorded after 1-year follow-up. RESULTS: Sixty-four patients with bronchiectasis were analysed, of whom 15 (23%) were hospitalised during the follow-up. Hospitalised patients showed poor baseline clinical and severity outcomes, fewer steps walked per day and more sedentary behaviour than the non-hospitalised group. Patients who walked ≤6290 steps·day-1 or spent ≥7.8 h·day-1 in sedentary behaviour had an increased risk of hospital admission due to bronchiectasis exacerbation at 1-year follow-up. Specifically, ≥7.8 h·day-1 of sedentary behaviour was associated with a 5.9-fold higher risk of hospital admission in the following year. CONCLUSIONS: Low levels of physical activity and high sedentary time at baseline were associated with a higher risk of hospitalisation due to bronchiectasis exacerbation. If these findings are validated in future studies, it might be appropriate to include physical activity and sedentary behaviour as an item in severity scores.

Pure Viral Sepsis Secondary to Community-Acquired Pneumonia in Adults: Risk and Prognostic Factors.

We investigated the risk and prognostic factors of pure viral sepsis in adult patients with community-acquired pneumonia (CAP), using the Sepsis-3 definition. Pure viral sepsis was found in 3% of all patients (138 of 4028) admitted to the emergency department with a diagnosis of CAP, 19% of those with CAP (138 of 722) admitted to the intensive care unit, and 61% of those (138 of 225) with a diagnosis of viral CAP. Our data indicate that males and patients aged ≥65 years are at increased risk of viral sepsis.

Community-Acquired Legionella Pneumonia in Human Immunodeficiency Virus-Infected Adult Patients: A Matched Case-Control Study.

We investigate whether the clinical presentations and outcomes of Legionella pneumonia in human immunodeficiency virus (HIV)-infected patients were comparable to those seen in non-HIV-infected patients (case-control design). HIV-infected individuals presented neither a more severe disease nor a worse clinical outcome than matched HIV-negative control patients.

Corticosteroids in Patients Hospitalized With Community-Acquired Pneumonia: Systematic Review and Individual Patient Data Metaanalysis.

Background: Our aim was to evaluate the benefits and harms of adjunctive corticosteroids in adults hospitalized with community-acquired pneumonia (CAP) using individual patient data from randomized, placebo-controlled trials and to explore subgroup differences. Methods: We systematically searched Medline, Embase, Cochrane Central, and trial registers (all through July 2017). Data from 1506 individual patients in 6 trials were analyzed using uniform outcome definitions. We investigated prespecified effect modifiers using multivariable hierarchical regression, adjusting for pneumonia severity, age, and clustering effects. Results: Within 30 days of randomization, 37 of 748 patients (5.0%) assigned to corticosteroids and 45 of 758 patients (5.9%) assigned to placebo died (adjusted odds ratio [aOR], 0.75; 95% confidence interval [CI], .46 to 1.21; P = .24). Time to clinical stability and length of hospital stay were reduced by approximately 1 day with corticosteroids (-1.03 days; 95% CI, -1.62 to -.43; P = .001 and -1.15 days; 95% CI, -1.75 to -.55; P < .001, respectively). More patients with corticosteroids had hyperglycemia (160 [22.1%] vs 88 [12.0%]; aOR, 2.15; 95% CI, 1.60 to 2.90; P < .001) and CAP-related rehospitalization (33 [5.0%] vs 18 [2.7%]; aOR, 1.85; 95% CI, 1.03 to 3.32; P = .04). We did not find significant effect modification by CAP severity or degree of inflammation. Conclusions: Adjunct corticosteroids for patients hospitalized with CAP reduce time to clinical stability and length of hospital stay by approximately 1 day without a significant effect on overall mortality but with an increased risk for CAP-related rehospitalization and hyperglycemia.

Acute respiratory distress syndrome in mechanically ventilated patients with community-acquired pneumonia.

Our aim was to assess the incidence, characteristics, aetiology, risk factors and mortality of acute respiratory distress syndrome (ARDS) in intensive care unit (ICU) patients with community-acquired pneumonia (CAP) using the Berlin definition.We prospectively enrolled consecutive mechanically ventilated adult ICU patients with CAP over 20 years, and compared them with mechanically ventilated patients without ARDS. The main outcome was 30-day mortality.Among 5334 patients hospitalised with CAP, 930 (17%) were admitted to the ICU and 432 required mechanical ventilation; 125 (29%) cases met the Berlin ARDS criteria. ARDS was present in 2% of hospitalised patients and 13% of ICU patients. Based on the baseline arterial oxygen tension/inspiratory oxygen fraction ratio, 60 (48%), 49 (40%) and 15 (12%) patients had mild, moderate and severe ARDS, respectively. Streptococcus pneumoniae was the most frequent pathogen, with no significant differences in aetiology between groups. Higher organ system dysfunction and previous antibiotic use were independent risk factors for ARDS in the multivariate analysis, while previous inhaled corticosteroids were independently associated with a lower risk. The 30-day mortality was similar between patients with and without ARDS (25% versus 30%, p=0.25), confirmed by propensity-adjusted multivariate analysis.ARDS occurs as a complication of CAP in 29% of mechanically ventilated patients, but is not related to the aetiology or mortality.

Clinical variables predicting the risk of a hospital stay for longer than 7 days in patients with severe acute exacerbations of chronic obstructive pulmonary disease: a prospective study.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) patients may experience an acute exacerbation (AECOPD) that requires hospitalisation. The length of hospital stay (LHS) has a great economic impact on the health-care system. Knowing the predictors of prolonged LHS could help to identify possible interventions. METHODS: We performed a prospective study to identify the clinical predictors of prolonged LHS in patients hospitalised for AECOPD. We divided the study sample by LHS into normal (≤7 days) and prolonged LHS (> 7 days) groups. Outcomes were the need for non-invasive and invasive mechanical ventilation (NIMV and IMV), intensive care unit (ICU) admission, and the 3-year mortality. RESULTS: We enrolled 437 patients, of which 213 and 224 had normal LHS and prolonged LHS, respectively. Patients with a prolonged LHS had more prior hospitalisations for AECOPD, a worse mMRC (modified Medical Research Council) dyspnoea score, a higher prevalence of long-term oxygen therapy and a higher rate of congestive heart disease. During the current admission, this group also tended to require NIMV, IMV and ICU admission and the mortality risks at 6 months, 1 year and 3 years were higher. In the multivariate regression analysis, an mMRC dyspnoea score ≥ 2 (odds ratio-OR 2.24; 95% confidence interval-CI 1.34 to 3.74; p = 0.002) and the presence of acute respiratory acidosis (OR 2.75; 95% CI 1.49 to 5.05; p = 0.001) predicted a prolonged LHS at admission. CONCLUSIONS: The presence of an mMRC ≥2 and acute respiratory acidosis at admission independently increased the risk of a prolonged LHS for AECOPD.

Microorganisms resistant to conventional antimicrobials in acute exacerbations of chronic obstructive pulmonary disease.

BACKGROUND: Antimicrobial treatment for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) remains controversial. In some cases AECOPD are caused by microorganisms that are resistant to treatments recommended by guidelines. Our aims were: 1) identify the risk factors associated with infection by microorganisms resistant to conventional treatment (MRCT), 2) Compare the clinical characteristics and outcomes of patients with AECOPD resulting from MRCT against those with AECOPD from other causes. METHODS: We prospective analysed a cohort of patients admitted with severe AECOPD (2009 to 2015) who were assigned to three groups: patients with MRCT (those patients with germs resistant to antibiotics recommended in guidelines), patients with microorganisms sensitive to conventional antimicrobial treatment (MSCT), and patients with negative microbiology results who had not previously received antibiotics. Multinomial logistic regression analyses were used to examine the associations between microbial aetiology groups and risk factors. The association between LOS and risk factors was also tested in simple and multiple analyses, and similar inclusion criteria were applied for the linear regression analysis. RESULTS: Of the 451 patients admitted, 195 patients (43%) were included. Respiratory cultures were positive in 86(44%) and negative in 109(56%). MRCT were isolated in 34 cases (40%) and MSCT in 52 (60%). Patients with MRCT had more AECOPD in the previous year, received more antibiotic treatment in the previous three months, had more severe disease, higher dyspnoea and a positive respiratory culture in the previous year (mainly for Pseudomonas aeruginosa). The following conditions were independent factors for MRCT isolation: non-current smoker (odds ratio [OR] 4.19 [95% confidence interval [CI] 1.29-13.67], p = 0.017), ≥ 2 AECOPD or ≥ 1 admission for AECOPD in the previous year (OR 4.13 [95% CI 1.52-11.17], p = 0.005), C-reactive protein < 5 mg/dL; (OR 3.58 [95% CI 1.41-9.07], p = 0.007). Mortality rates were comparable at 30-days, one year and 3 years; however, patients in the MRCT group had longer hospital stays. CONCLUSION: In conclusion, there are risk factors for resistant germs in AECOPD; however, the presence of these germs does not increase mortality. Patients with isolation of MRCT had longer length of stay.

New Sepsis Definition (Sepsis-3) and Community-acquired Pneumonia Mortality. A Validation and Clinical Decision-Making Study.

RATIONALE: The Sepsis-3 Task Force updated the clinical criteria for sepsis, excluding the need for systemic inflammatory response syndrome (SIRS) criteria. The clinical implications of the proposed flowchart including the quick Sequential (Sepsis-related) Organ Failure Assessment (qSOFA) and SOFA scores are unknown. OBJECTIVES: To perform a clinical decision-making analysis of Sepsis-3 in patients with community-acquired pneumonia. METHODS: This was a cohort study including adult patients with community-acquired pneumonia from two Spanish university hospitals. SIRS, qSOFA, the Confusion, Respiratory Rate and Blood Pressure (CRB) score, modified SOFA (mSOFA), the Confusion, Urea, Respiratory Rate, Blood Pressure and Age (CURB-65) score, and Pneumonia Severity Index (PSI) were calculated with data from the emergency department. We used decision-curve analysis to evaluate the clinical usefulness of each score and the primary outcome was in-hospital mortality. MEASUREMENTS AND MAIN RESULTS: Of 6,874 patients, 442 (6.4%) died in-hospital. SIRS presented the worst discrimination, followed by qSOFA, CRB, mSOFA, CURB-65, and PSI. Overall, overestimation of in-hospital mortality and miscalibration was more evident for qSOFA and mSOFA. SIRS had lower net benefit than qSOFA and CRB, significantly increasing the risk of over-treatment and being comparable with the "treat-all" strategy. PSI had higher net benefit than mSOFA and CURB-65 for mortality, whereas mSOFA seemed more applicable when considering mortality/intensive care unit admission. Sepsis-3 flowchart resulted in better identification of patients at high risk of mortality. CONCLUSIONS: qSOFA and CRB outperformed SIRS and presented better clinical usefulness as prompt tools for patients with community-acquired pneumonia in the emergency department. Among the tools for a comprehensive patient assessment, PSI had the best decision-aid tool profile.

Seasonality of pathogens causing community-acquired pneumonia.

BACKGROUND AND OBJECTIVE: Seasonal distribution of microbial aetiology in patients with community-acquired pneumonia (CAP) may add important information both for epidemiologists and clinicians. We investigate the seasonal distribution of microbial aetiology in CAP. METHODS: This prospective observational study was carried out in the Hospital Clinic of Barcelona, Spain (January 2003-December 2014). RESULTS: We studied 4431 patients with CAP, of whom 2689 (61%) were males. Microbial aetiology was identified in 1756 patients (40%). CAP was most frequent in winter (34%) but two-third of patients with CAP presented in other seasons. Seasonal variations included Streptococcus pneumoniae (winter 21% vs spring 17% vs summer 14% vs autumn 13%, overall P < 0.001). Influenza viruses were most prevalent in autumn (6%) and winter (5%) compared with spring (3%) and summer (1%) (overall P < 0.001). Legionella pneumophila was most frequent in autumn (4%) and summer (4%) compared with spring (2%) and winter (1%) (overall P < 0.001). Incidence of polymicrobial pneumonia also differed between seasons (winter 7% vs spring 5% vs summer 3% vs autumn 6%, overall P = 0.001). We observed a significant correlation between the lowest seasonal average temperature and polymicrobial pneumonia, pneumococcal pneumonia, and influenza viruses; conversely, L. pneumophila was more common when temperatures were higher. CONCLUSION: CAP should not be regarded as a seasonal disease but occurs throughout all seasons. However, S. pneumoniae, influenza viruses, polymicrobial pneumonia and L. pneumophila are clearly subject to seasonal variations.

Predictive and prognostic factors in patients with blood-culture-positive community-acquired pneumococcal pneumonia.

In patients with pneumococcal community-acquired pneumonia (CAP), the risk factors for bacteraemia and its impact on outcomes are not fully elucidated. We aimed to compare characteristics of patients with blood-culture-positive versus blood-culture-negative pneumococcal CAP, and to characterise bacteraemic serotypes.We describe a prospective, observational study on nonimmunocompromised patients with pneumococcal CAP, from 1996 to 2013. We define severe pneumonia according to American Thoracic Society/Infectious Diseases Society of America guidelines.Of a total of 917 patients with pneumococcal CAP, 362 had blood-culture-positive pneumococcal pneumonia (BCPPP; 39%). High C-reactive protein (CRP) (≥20 mg·dL(-1)) (odds ratio (OR) 2.36, 95% CI 1.45-3.85), pleural effusion (OR 2.03, 95% CI 1.13-3.65) and multilobar involvement (OR 1.69, 95% CI 1.02-2.79) were independently associated with bacteraemic CAP, while nursing home resident (OR 0.12, 95% CI 0.01-1.00) was found as a protective factor. Despite the clinical differences, BCPPP showed similar outcomes to blood-culture-negative pneumococcal pneumonia (BCNPP). 14% of the serotypes (period 2006-2013) causing bacteraemia are included in pneumococcal conjugate vaccine PVC7, 74% in pneumococcal conjugate vaccine PVC13 and 83% in pneumococcal polysaccharide vaccine PPSV23.Pleural effusion, a high level of CRP and multilobar involvement predicted an increased risk of BCPPP. Although BCPPP patients were more severely ill at admission, mortality was not significantly greater than in BCNPP patients.

The Effect of Macrolide Resistance on the Presentation and Outcome of Patients Hospitalized for Streptococcus pneumoniae Pneumonia.

RATIONALE: There are conflicting reports describing the effect of macrolide resistance on the presentation and outcomes of patients with Streptococcus pneumoniae pneumonia. OBJECTIVES: We aimed to determine the effect of macrolide resistance on the presentation and outcomes of patients with pneumococcal pneumonia. METHODS: We conducted a retrospective, observational study in the Hospital Clinic of Barcelona of all adult patients hospitalized with pneumonia who had positive cultures for S. pneumoniae from January 1, 2000 to December 31, 2013. Outcomes examined included bacteremia, pulmonary complications, acute renal failure, shock, intensive care unit admission, need for mechanical ventilation, length of hospital stay, and 30-day mortality. MEASUREMENTS AND MAIN RESULTS: Of 643 patients hospitalized for S. pneumoniae pneumonia, 139 (22%) were macrolide resistant. Patients with macrolide-resistant organisms were less likely to have bacteremia, pulmonary complications, and shock, and were less likely to require noninvasive mechanical ventilation. We found no increase in the incidence of acute renal failure, the frequency of intensive care unit admission, the need for invasive ventilatory support, the length of hospital stay, or the 30-day mortality in patients with (invasive or noninvasive) macrolide-resistant S. pneumoniae pneumonia, and no effect on outcomes as a function of whether treatment regimens did or did not comply with current guidelines. CONCLUSIONS: We found no evidence suggesting that patients hospitalized for macrolide-resistant S. pneumoniae pneumonia were more severely ill on presentation or had worse clinical outcomes if they were treated with guideline-compliant versus noncompliant regimens.

Predicting In-Hospital Treatment Failure (≤ 7 days) in Patients with COPD Exacerbation Using Antibiotics and Systemic Steroids.

Although pharmacological treatment of COPD exacerbation (COPDE) includes antibiotics and systemic steroids, a proportion of patients show worsening of symptoms during hospitalization that characterize treatment failure. The aim of our study was to determine in-hospital predictors of treatment failure (≤ 7 days). Prospective data on 110 hospitalized COPDE patients, all treated with antibiotics and systemic steroids, were collected; on the seventh day of hospitalization, patients were divided into treatment failure (n = 16) or success (n = 94). Measures of inflammatory serum biomarkers were recorded at admission and at day 3; data on clinical, laboratory, microbiological, and severity, as well data on mortality and readmission, were also recorded. Patients with treatment failure had a worse lung function, with higher serum levels of C-reactive protein (CRP), procalcitonin (PCT), tumour necrosis factor-alpha (TNF-α), interleukin (IL) 8, and IL-10 at admission, and CRP and IL-8 at day 3. Longer length of hospital stay and duration of antibiotic therapy, higher total doses of steroids and prevalence of deaths and readmitted were found in the treatment failure group. In the multivariate analysis, +1 mg/dL of CRP at admission (OR, 1.07; 95% CI, 1.01 to 1.13) and use of penicillins or cephalosporins (OR, 5.63; 95% CI, 1.26 to 25.07) were independent variables increasing risk of treatment failure, whereas cough at admission (OR, 0.20; 95% CI, 0.05 to 0.75) reduces risk of failure. In hospitalized COPDE patients CRP at admission and use of specific class of antibiotics predict in-hospital treatment failure, while presence of cough has a protective role.

Bacteraemia and antibiotic-resistant pathogens in community acquired pneumonia: risk and prognosis.

The sensitivity of blood cultures in the diagnosis of bacteraemia for community-acquired pneumonia is low. Recommendations, by guidelines, to perform blood cultures are discordant. We aimed to determine the incidence, microbial aetiology, risk factors and outcomes of bacteraemic patients with community-acquired pneumonia, including cases with antibiotic-resistant pathogens (ARP). A prospective, observational study was undertaken on consecutive adult patients admitted to the Hospital Clinic of Barcelona (Barcelona, Spain) with community-acquired pneumonia and blood cultures were obtained. Of the 2892 patients included, bacteraemia was present in 297 (10%) patients; 30 (10%) of whom had ARP (multidrug-resistant Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and an extended spectrum of beta-lactamase producing Enterobacteriaceae). In multivariate analyses, pleuritic pain, C-reactive protein ≥21.6 mg·dL(-1) and intensive care unit admissions were independently associated with bacteraemia, while prior antibiotic treatment and pneumococcal vaccine were protective factors. The risk factors for ARP bacteraemia were previous antibiotics and C-reactive protein <22.2 mg·dL(-1), while pleuritic pain was the only protective factor in the multivariate analysis. Bacteraemia (excluding ARP), appropriate empiric treatment, neurological disease, arterial oxygen tension/inspiratory oxygen fraction <250, pneumonia severity index risk classes IV and V, and intensive care unit admission were independently associated with a 30-day hospital mortality in the multivariate analysis. Inappropriate therapy was more frequent in ARP bacteraemia, compared with other bacteraemias (27% versus 3%, respectively, p<0.001). Antibiotic therapy protected against bacteraemia, but increased specifically the risk of bacteraemia from ARP due to the inappropriate coverage of these pathogens. Identifying patients at risk of ARP bacteraemia would help in deciding appropriate empiric antimicrobial therapy. The results from this study provide evidence concerning community-acquired pneumonia patients in whom blood cultures should not be performed.

Polymicrobial intensive care unit-acquired pneumonia: prevalence, microbiology and outcome.

BACKGROUND: Microbial aetiology of intensive care unit (ICU)-acquired pneumonia (ICUAP) determines antibiotic treatment and outcomes. The impact of polymicrobial ICUAP is not extensively known. We therefore investigated the characteristics and outcomes of polymicrobial aetiology of ICUAP. METHOD: Patients with ICUAP confirmed microbiologically were prospectively compared according to identification of 1 (monomicrobial) or more (polymicrobial) potentially-pathogenic microorganisms. Microbes usually considered as non-pathogenic were not considered for the etiologic diagnosis. We assessed clinical characteristics, microbiology, inflammatory biomarkers and outcome variables. RESULTS: Among 441 consecutive patients with ICUAP, 256 (58%) had microbiologic confirmation, and 41 (16%) of them polymicrobial pneumonia. Methicillin-sensitive Staphylococcus aureus, Haemophilus influenzae, and several Enterobacteriaceae were more frequent in polymicrobial pneumonia. Multi-drug and extensive-drug resistance was similarly frequent in both groups. Compared with monomicrobial, patients with polymicrobial pneumonia had less frequently chronic heart disease (6, 15% vs. 71, 33%, p = 0.019), and more frequently pleural effusion (18, 50%, vs. 54, 25%, p = 0.008), without any other significant difference. Appropriate empiric antimicrobial treatment was similarly frequent in the monomicrobial (185, 86%) and the polymicrobial group (39, 95%), as were the initial response to the empiric treatment, length of stay and mortality. Systemic inflammatory response was similar comparing monomicrobial with polymicrobial ICUAP. CONCLUSION: The aetiology of ICUAP confirmed microbiologically was polymicrobial in 16% cases. Pleural effusion and absence of chronic heart disease are associated with polymicrobial pneumonia. When empiric treatment is frequently appropriate, polymicrobial aetiology does not influence the outcome of ICUAP.