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Background: The inflammatory response in community-acquired pneumonia (CAP) depends on the host and on the challenge of the causal microorganism. Here, we analyze the patterns of inflammatory cytokines, procalcitonin (PCT), and C-reactive protein (CRP) in order to determine their diagnostic value.Methods: This was a prospective study of 658 patients admitted with CAP. PCT and CRP were analyzed by immunoluminometric and immunoturbidimetric assays. Cytokines (tumor necrosis factor-α [TNF-α], IL-1β, IL-6, IL-8, and IL-10) were measured using enzyme immunoassay.Results: The lowest medians of CRP, PCT, TNF-α, and IL-6 were found in CAP of unknown cause, and the highest were found in patients with positive blood cultures. Different cytokine profiles and biomarkers were found depending on cause: atypical bacteria (lower PCT and IL-6), viruses (lower PCT and higher IL-10), Enterobacteriaceae (higher IL-8), Streptococcus pneumoniae (high PCT), and Legionella pneumophila (higher CRP and TNF-α). PCT ≥ 0.36 mg/dL to predict positive blood cultures showed sensitivity of 85%, specificity of 42%, and negative predictive value (NPV) of 98%, whereas a cutoff of ≤ 0.5 mg/dL to predict viruses or atypicals vs bacteria showed sensitivity of 89%/81%, specificity of 68%/68%, positive predictive value of 12%/22%, and NPV of 99%/97%. In a multivariate Euclidean distance model, the lowest inflammatory expression was found in unknown cause and the highest was found in L pneumophila, S pneumoniae, and Enterobacteriaceae. Atypical bacteria exhibit an inflammatory pattern closer to that of viruses.Conclusions: Different inflammatory patterns elicited by different microorganisms may provide a useful tool for diagnosis. Recognizing these patterns provides additional information that may facilitate a broader understanding of host inflammatory response to microorganisms. [ABSTRACT FROM AUTHOR]

Background: A shortage of beds in ICUs and conventional wards during the COVID-19 pandemic led to a collapse of health care resources., Research Question: Can admission data and minor criteria by the Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) help identify patients with low-risk SARS-CoV-2 pneumonia?, Study Design and Methods: This multicenter cohort study included 1,274 patients in a derivation cohort and 830 (first wave) and 754 (second wave) patients in two validation cohorts. A multinomial regression analysis was performed on the derivation cohort to compare the following patients: those admitted to the ward (assessed as low risk); those admitted to the ICU directly; those transferred to the ICU after general ward admission; and those who died. A regression analysis identified independent factors for low-risk pneumonia. The model was subsequently validated., Results: In the derivation cohort, similarities existed among those either directly admitted or transferred to the ICU and those who died. These patients could, therefore, be merged into one group. Five independently associated factors were identified as being predictors of low risk (not dying and/or requiring ICU admission) (ORs, with 95% CIs): peripheral blood oxygen saturation/Fio 2 > 450 (0.233; 0.149-0.364); < 3 IDSA/ATS minor criteria (0.231; 0.146-0.365); lymphocyte count > 723 cells/mL (0.539; 0.360-0.806); urea level < 40 mg/dL (0.651; 0.426-0.996); and C-reactive protein level < 60 mg/L (0.454; 0.285-0.724). The areas under the curve were 0.802 (0.769-0.835) in the derivation cohort, and 0.779 (0.742-0.816) and 0.801 (0.757-0.845) for the validation cohorts (first and second waves, respectively)., Interpretation: Initial biochemical findings and the application of < 3 IDSA/ATS minor criteria make early identification of low-risk SARS-CoV-2 pneumonia (approximately 80% of hospitalized patients) feasible. This scenario could facilitate and streamline health care resource allocation for patients with COVID-19., (Copyright © 2022 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Background: The study aimed to investigate whether the clinical presentations and outcomes (length of stay, ICU admission, and 30-day mortality) of pneumococcal pneumonia in virologically suppressed patients who were HIV-infected on ART with a CD4+ T-cell count > 350 cells/mm 3 are comparable to those seen in patients with HIV, using a case-control design., Methods: A case-control study was carried out in Hospital Clinic, Barcelona, Spain (2001-2016). Control patients were matched by age (±10 years), sex, comorbidities, and pneumonia diagnosis in the same calendar period. Clinical presentation and outcomes of pneumococcal pneumonia in patients who were and were not infected with HIV were compared., Results: Pneumococcal pneumonia was studied in 50 cases (HIV infection) and 100 control patients (non-HIV infection). Compared with the control patients, case patients had higher rates of influenza (14% vs 2%, P = .007) and pneumococcal vaccination (10% vs 1%, P = .016). The group of cases also presented a higher rate of coinfection with hepatitis B virus (6% vs 0%, P = .036). Both groups presented similar ICU admission (18% vs 27%, P = .22), need for mechanical ventilation (12% vs 8%; P = .43), length of stay (7 days vs 7 days, P = .76), and 0% of 30-day mortality. No evidence was found of a more severe presentation or a worse clinical outcome in cases than in control patients., Conclusions: Pneumococcal pneumonia episodes requiring hospitalization in virologically suppressed patients with HIV with > 350 CD4+ T-cell count/mm 3 were neither more severe nor had worse prognosis compared with uninfected patients. These results support the fact that such patients do not need treatment, admission, or care sites different to the general population., Trial Registry: ClinicalTrials.gov; No. 2009/5451; URL: www.clinicaltrials.gov., (Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Background: Pseudomonas aeruginosa is not a frequent pathogen in community-acquired pneumonia (CAP). However, in patients with severe CAP, P aeruginosa can be the etiology in 1.8% to 8.3% of patients, with a case-fatality rate of 50% to 100%. We describe the prevalence, clinical characteristics, outcomes, and risk factors associated with CAP resulting from multidrug-resistant (MDR) and non-MDR P aeruginosa., Methods: Prospective observational study of 2,023 consecutive adult patients with CAP with definitive etiology., Results: P aeruginosa was found in 77 (4%) of the 2,023 cases with microbial etiology. In 22 (32%) of the 68 cases of P aeruginosa with antibiogram data, the isolates were MDR. Inappropriate therapy was present in 49 (64%) cases of P aeruginosa CAP, including 17/22 (77%) cases of MDR P aeruginosa CAP. Male sex, chronic respiratory disease, C-reactive protein <12.35 mg/dL, and pneumonia severity index risk class IV to V were independently associated with P aeruginosa CAP. Prior antibiotic treatment was more frequent in MDR P aeruginosa CAP compared with non-MDR P aeruginosa (58% vs 29%, P = .029), and was the only risk factor associated with CAP resulting from MDR P aeruginosa. In the multivariate analysis, age ≥65 years, CAP resulting from P aeruginosa, chronic liver disease, neurologic disease, nursing home, criteria of ARDS, acute renal failure, ICU admission, and inappropriate empiric treatment were the factors associated with 30-day mortality., Conclusions: P aeruginosa is an individual risk factor associated with mortality in CAP. The risk factors described can help clinicians to suspect P aeruginosa and MDR P aeruginosa., (Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Background: Prolonged life expectancy has currently increased the proportion of the very elderly among patients with community-acquired pneumonia (CAP). The aim of this study was to determine the influence of age and comorbidity on microbial patterns in patients over 65 years of age with CAP., Methods: This study was a prospective observational study of adult patients with CAP (excluding those in nursing homes) over a 12-year period. We compared patients aged 65 to 74 years, 75 to 84 years, and > 85 years for potential differences in clinical presentation, comorbidities, severity on admission, microbial investigations, causes, antimicrobial treatment, and outcomes., Results: We studied a total of 2,149 patients: 759 patients (35.3%) aged 65 to 74 years, 941 patients (43.7%) aged 75 to 84 years, and 449 patients (20.8%) aged > 85 years. At least one comorbidity was present in 1,710 patients (79.6%). Streptococcus pneumoniae was the most frequent pathogen in all age groups, regardless of comorbidity. Staphylococcus aureus, Enterobacteriaceae, and Pseudomonas aeruginosa accounted for 9.1% of isolates, and Haemophilus influenzae, 6.4%. All these pathogens were isolated only in patients with at least one comorbidity. Mortality increased with age (65-74 years, 6.9%; 75-84 years, 8.9%; > 85 years, 17.1%; P < .001) and was associated with increased comorbidities (neurologic; OR, 2.1; 95% CI, 1.5-2.1), Pneumonia Severity Index IV or V (OR, 3.2; 95% CI, 1.8-6.0), bacteremia (OR, 1.7; 95% CI, 1.1-2.7), the presence of a potential multidrug-resistant (MDR) pathogen (S. aureus, P. aeruginosa, Enterobacteriaceae; OR, 2.4; 95% CI, 1.3-4.3), and ICU admission (OR, 4.2; 95% CI, 2.9-6.1) on multivariate analysis., Conclusions: Age does not influence microbial cause itself, whereas comorbidities are associated with specific causes such as H. influenzae and potential MDR pathogens. Mortality in the elderly is mainly driven by the presence of comorbidities and potential MDR pathogens.

Background: Thrombocytosis, often considered a marker of normal inflammatory reaction of infections, has been recently associated with increased mortality in hospitalized patients with community-acquired pneumonia (CAP). We assessed the characteristics and outcomes of patients with CAP and thrombocytosis (platelet count ≥ 4 × 105/mm3) compared with thrombocytopenia (platelet count &lt; 105/mm3) and normal platelet count., Methods: We prospectively analyzed 2,423 consecutive, hospitalized patients with CAP. We excluded patients with immunosuppression, neoplasm, active TB, or hematologic disease., Results: Fifty-three patients (2%) presented with thrombocytopenia, 204 (8%) with thrombocytosis, and 2,166 (90%) had normal platelet counts. Patients with thrombocytosis were younger (P &lt; .001); those with thrombocytopenia more frequently had chronic heart and liver disease (P &lt; .001 for both). Patients with thrombocytosis presented more frequently with respiratory complications, such as complicated pleural effusion and empyema (P &lt; .001), whereas those with thrombocytopenia presented more often with severe sepsis (P &lt; .001), septic shock (P = .009), need for invasive mechanical ventilation (P &lt; .001), and ICU admission (P = .011). Patients with thrombocytosis and patients with thrombocytopenia had longer hospital stays (P = .004), and higher 30-day mortality (P = .001) and readmission rates (P = .011) than those with normal platelet counts. Multivariate analysis confirmed a significant association between thrombocytosis and 30-day mortality (OR, 2.720; 95% CI, 1.589-4.657; P &lt; .001). Adding thrombocytosis to the confusion, respiratory rate, and BP plus age ≥65 years score slightly improved the accuracy to predict mortality (area under the receiver operating characteristic curve increased from 0.634 to 0.654, P = .049)., Conclusions: Thrombocytosis in patients with CAP is associated with poor outcome, complicated pleural effusion, and empyema. The presence of thrombocytosis in CAP should encourage ruling out respiratory complication and could be considered for severity evaluation.