Does etiological investigation have an impact on the outcomes of community-acquired pneumonia? – A prospective cohort study

  • J. Vasco Barreto
    Corresponding author at: Rua Dr. Eduardo Torres, Senhora da Hora 4464-513, Portugal.
    Medicine Department, Hospital Pedro Hispano, Matosinhos Local Health Unit, Internal Medicine Service, Rua Dr. Eduardo Torres, Senhora da Hora 4464-513, Portugal

    ICBAS – School of Medicine and Biomedical Sciences, University of Porto, Rua Jorge de Viterbo Ferreira 228, Porto 4050-313, Portugal
    Search for articles by this author
  • Cláudia Camila Dias
    Knowledge Management Unit and Department of Community Medicine, Information and Health Decision Sciences, Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, Porto 4200-319, Portugal

    [email protected] - Health Research Netwok – From Lab to the Community, Alameda Prof. Hernâni Monteiro, Porto 4200-319, Portugal
    Search for articles by this author
  • Teresa Cardoso
    ICBAS – School of Medicine and Biomedical Sciences, University of Porto, Rua Jorge de Viterbo Ferreira 228, Porto 4050-313, Portugal

    Intensive Care Unit (UCIP) and Hospital Infection Control Committee, Hospital de Santo António, Oporto University Hospital Center, University of Porto, Largo Prof. Abel Salazar, Porto 4099-001, Portugal
    Search for articles by this author
Published:December 06, 2022DOI:


      • There is lack of evidence that etiological investigation influences outcomes in CAP.
      • In a prospective study, we evaluate if microbial identification impacts mortality.
      • Etiology identification was not significantly associated with mortality (aOR=1.36, p=0.2).
      • This lack of association was verified in all drug resistant pathogen risk groups.
      • Results of etiological investigation have a limited influence in CAP management.



      There is lack of evidence that etiological investigation influences outcomes in community-acquired pneumonia (CAP). Guidelines recommend diverse approaches to this matter. Our aim was to find if etiological investigation has an impact on CAP management and outcomes.


      Prospective cohort study, conducted over a two years’ period, in a community-based hospital, including all adult patients with CAP. Univariate and multivariate logistic regression modeling were performed to understand the association of etiological identification with CAP outcomes, particularly hospital mortality.


      A total of 660 cases of CAP were included, with a mean±sd age of 74±15 years and 58.9% of males. Etiology was documented in 33% of cases. Antibiotic (ATB) was modified in 148 patients, in 51 (34%) motivated by microbiological results. There was no significant impact on hospital mortality of microbiological documentation (35.5% vs 31.2%, p=0.352), or the fact that ATB was modified due to microbiological findings (27.0% vs 36.9%, p=0.272). When stratified by 3 subgroups of risk for drug-resistant pathogens (zero, one or two risk factors: being bed-ridden and/or ATB use within 90 days), etiology identification still did not influence mortality. When adjusted for CURB-65, Charlson's index, being bed-ridden, having had ATB or hospitalization within 90 days or coming from long-term care facilities, microbial identification was not associated with lower mortality.


      Etiological investigation of patients with CAP does not have an association with hospital mortality, irrespective of the risk for drug-resistant pathogens.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to European Journal of Internal Medicine
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Jain S.
        • Self W.H.
        • Wunderink R.G.
        • et al.
        Community-acquired pneumonia requiring hospitalization among U.S. adults.
        N Engl J Med. 2015; 373: 415-427
        • Metlay J.P.
        • Waterer G.W.
        • Long A.C.
        • Anzueto A.
        • Brozek J.
        • Crothers K.
        • Cooley L.A.
        • Dean N.C.
        • Fine M.J.
        • Flanders S.A.
        • Griffin M.R.
        • Metersky M.L.
        • Musher D.M.
        • Restrepo M.I.
        • Whitney CG.
        Diagnosis and treatment of adults with community- acquired pneumonia. an official clinical practice guideline of the American thoracic society and infectious diseases society of America.
        Am J Respir Crit Care Med. 2019; 200 (Oct 1): e45-e67
        • Aliberti S.
        • Cilloniz C.
        • Chalmers J.D.
        • Zanaboni A.M.
        • Cosentini R.
        • Tarsia P.
        • Pesci A.
        • Blasi F.
        • Torres A.
        Multidrug-resistant pathogens in hospitalised patients coming from the community with pneumonia: a European perspective.
        Thorax. 2013; 68 (NovEpub 2013 Jun 17. PMID: 23774884): 997-999
        • Restrepo M.I.
        • Babu B.L.
        • Reyes L.F.
        • et al.
        Burden and risk factors for pseudomonas aeruginosa community-acquired pneumonia: a multinational point prevalence study of hospitalised patients.
        Eur Respir J. 2018; 521709910
        • Aliberti S.
        • Reyes L.F.
        • Faverio P.
        • Sotgiu G.
        • Dore S.
        • Rodriguez A.H.
        • et al.
        Global initiative for methicillin-resistant Staphylococcus aureus pneumonia (GLIMP): an international, observational cohort study.
        Lancet Infect Dis. 2016; 16: 1364-1376
        • Waterer G.W.
        • Jennings S.G.
        • Wunderink R.G.
        The impact of blood cultures on antibiotic therapy in pneumococcal pneumonia.
        Chest. 1999; 116 (NovPMID: 10559087.)): 1278-1281
        • Benenson R.S.
        • Kepner A.M.
        • Pyle 2nd, D.N.
        • Cavanaugh S.
        Selective use of blood cultures in emergency department pneumonia patients.
        J Emerg Med. 2007; 33 (JulEpub 2007 Jun 18. PMID: 17630066.)): 1-8
        • Ewig S.
        • Schlochtermeier M.
        • Göke N.
        • Niederman MS.
        Applying sputum as a diagnostic tool in pneumonia: limited yield, minimal impact on treatment decisions.
        Chest. 2002; 121 (MayPMID: 12006433): 1486-1492
        • Rosón B.
        • Carratalà J.
        • Verdaguer R.
        • Dorca J.
        • Manresa F.
        • Gudiol F.
        Prospective study of the usefulness of sputum Gram stain in the initial approach to community-acquired pneumonia requiring hospitalization.
        Clin Infect Dis. 2000; 31 (OctEpub 2000 Oct 12. PMID: 11049763): 869-874
        • Shariatzadeh M.R.
        • Marrie T.J.
        Does sputum culture affect the management and/or outcome of community-acquired pneumonia?.
        East Mediterr Health J. 2009; 15 (Jul-AugPMID: 20187530): 792-799
        • Lidman C.
        • Burman L.G.
        • Lagergren A.
        • Ortqvist A.
        Limited value of routine microbiological diagnostics in patients hospitalized for community-acquired pneumonia.
        Scand J Infect Dis. 2002; 34 (PMID: 12587618): 873-879
        • Van der Eerden M.M.
        • Vlaspolder F.
        • de Graaff C.S.
        • Groot T.
        • Bronsveld W.
        • Jansen H.M.
        • Boersma W.G.
        Comparison between pathogen directed antibiotic treatment and empirical broad spectrum antibiotic treatment in patients with community acquired pneumonia: a prospective randomised study.
        Thorax. 2005; 60 (AugPMID: 16061709; PMCID: PMC1747487): 672-678
        • Ewig S.
        • Torres A.
        • Angeles Marcos M.
        • Angrill J.
        • Rañó A.
        • de Roux A.
        • Mensa J.
        • Martínez J.A.
        • de la Bellacasa J.P.
        • Bauer T.
        Factors associated with unknown aetiology in patients with community-acquired pneumonia.
        Eur Respir J. 2002; 20 (NovPMID: 12449182): 1254-1262
        • Waterer G.
        Breathing hope into directed therapy for pulmonary infections.
        Am J Respir Crit Care Med. 2021; 204 (Nov 1PMID: 34461037; PMCID: PMC8663018): 1011-1013
        • Woodhead M.
        • Blasi F.
        • Ewig S.
        • Garau J.
        • Huchon G.
        • Ieven M.
        • Ortqvist A.
        • Schaberg T.
        • Torres A.
        • van der Heijden G.
        • Read R.
        • Verheij T.J.M.
        Joint taskforce of the european respiratory society and european society for clinical microbiology and infectious diseases. Guidelines for the management of adult lower respiratory tract infections - full version.
        Clin Microbiol Infect. 2011; 17: E1-59
        • Lim W.S.
        • Baudouin S.V.
        • George R.C.
        • et al.
        BTS guidelines for the management of community acquired pneumonia in adults: update.
        Thorax. 2009; 64 (2009) (iii1-iii55)
        • Pletz M.W.
        • Blasi F.
        • Chalmers J.D.
        • Dela Cruz C.S.
        • Feldman C.
        • Luna C.M.
        • Ramirez J.A.
        • Shindo Y.
        • Stolz D.
        • Torres A.
        • Webb B.
        • Welte T.
        • Wunderink R.
        • Aliberti S.
        International perspective on the new 2019 American thoracic society/infectious diseases society of America community-acquired pneumonia guideline: a critical appraisal by a global expert panel.
        Chest. 2020; 158 (NovEpub 2020 Aug 25. PMID: 32858009; PMCID: PMC7445464): 1912-1918
        • Torres A.
        • Cilloniz C.
        • Niederman M.S.
        • et al.
        Nat Rev Dis Primers. 2021; 7: 25
        • Dellinger R.P.
        • Levy M.M.
        • Rhodes A.
        • et al.
        Surviving sepsis campaign guidelines committee including the pediatric subgroup. surviving sepsis campaign: international guidelines for management of severe sepsis and septic shock, 2012.
        Intensive Care Med. 2013; 39: 165-228
        • Society American Thoracic
        Infectious diseases society of America. Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia.
        Am J Respir Crit Care Med. 2005; 171: 388-416
        • Vestbo J.
        • Hurd S.S.
        • Agustí A.G.
        • Jones P.W.
        • Vogelmeier C.
        • Anzueto A.
        • Barnes P.J.
        • Fabbri L.M.
        • Martinez F.J.
        • Nishimura M.
        • Stockley R.A.
        • Sin D.D.
        • Rodriguez-Roisin R.
        Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD executive summary.
        Am J Respir Crit Care Med. 2013; 187 (Feb 15): 347-365
        • The Criteria Committee of the New York Heart Association
        Nomenclature and criteria for diagnosis of diseases of the heart and great vessels.
        9th ed. Little, Brown & Co, Boston, Mass1994: 253-266
        • Stevens P.E.
        • Levin A.
        • Disease Kidney
        Improving global outcomes chronic kidney disease guideline development work group members. evaluation and management of chronic kidney disease: synopsis of the kidney disease: improving global outcomes 2012 clinical practice guideline.
        Ann Intern Med. 2013; 158 (Jun 4): 825-830
        • Pugh R.N.
        • Murray-Lyon I.M.
        • Dawson J.L.
        • Pietroni M.C.
        • Williams R.
        Transection of the oesophagus for bleeding oesophageal varices.
        Br J Surg. 1973; 60 (Aug): 646-649
        • Mandell L.A.
        • Wunderink R.G.
        • Anzueto A.
        • Bartlett J.G.
        • Campbell G.D.
        • Dean N.C.
        • et al.
        Infectious diseases society of America/American thoracic society consensus guidelines on the management of communityacquired pneumonia in adults.
        Clin Infect Dis. 2007; 44 (1 March): S27-S72
        • Charlson Mary E.
        • et al.
        A new method of classifying prognostic comorbidity in longitudinal studies: development and validation.
        J Chronic Dis. 1987; 40: 373-383
        • Katz S.
        • Down T.D.
        • Cash H.R.
        • Grotz RC.
        Progress in the development of the index of ADL.
        Gerontologist. 1970; 10: 20-30
        • Prina E.
        • Ranzani O.T.
        • Polverino E.
        • Cilloniz C.
        • Ferrer M.
        • Fernandez L.
        • Puig de la Bellacasa J.
        • Menendez R.
        • Mensa J.
        • Torres A.
        Risk factors associated with potentially antibiotic-resistant pathogens in community-acquired pneumonia.
        Ann Am Thorac Soc. 2015; 12: 153-160
        • Barreto J.V.
        • Dias C.C.
        • Cardoso T.
        Risk factors for community-onset pneumonia caused by drug-resistant pathogens: a prospective cohort study.
        Eur J Intern Med. 2022; 96 (FebEpub 2021 Oct 18. PMID: 34670681): 66-73
        • Bernabeu-Wittel M.
        • Ollero-Baturone M.
        • Moreno-Gaviño L.
        • Barón-Franco B.
        • Fuertes A.
        • Murcia-Zaragoza J.
        • Ramos-Cantos C.
        • Alemán A.
        • Fernández-Moyano A.
        Development of a new predictive model for polypathological patients. The PROFUND index.
        Eur J Intern Med. 2011; 22 (JunEpub 2010 Dec 22. PMID: 21570654): 311-317
        • Gastli N.
        • Loubinoux J.
        • Daragon M.
        • Lavigne J.P.
        • Saint-Sardos P.
        • Pailhoriès H.
        • Lemarié C.
        • Benmansour H.
        • d'Humières C.
        • Broutin L.
        • Dauwalder O.
        • Levy M.
        • Auger G.
        • Kernéis S.
        • Cattoir V.
        • French FA-PP study group
        Multicentric evaluation of biofire filmarray pneumonia Panel for rapid bacteriological documentation of pneumonia.
        Clin Microbiol Infect. 2021; 27 (SepEpub 2020 Dec 1. PMID: 33276137): 1308-1314
        • Torres A.
        • Lee N.
        • Cilloniz C.
        • Vila J.
        Laboratory diagnosis of pneumonia in the molecular age.
        Eur Respir J. 2016; 48 (DecEpub 2016 Nov 3. PMID: 27811073): 1764-1778