Impact of microbial Aetiology on mortality in severe community-acquired pneumonia

Abstract

BackgroundThe impact of different classes of microbial pathogens on mortality in severe community-acquired pneumonia is not well elucidated. Previous studies have shown significant variation in the incidence of viral, bacterial and mixed infections, with conflicting risk associations for mortality. We aimed to determine the risk association of microbial aetiologies with hospital mortality in severe CAP, utilising a diagnostic strategy incorporating molecular testing. Our primary hypothesis was that respiratory viruses were important causative pathogens in severe CAP and was associated with increased mortality when present with bacterial pathogens in mixed viral-bacterial co-infections.MethodsA retrospective cohort study from January 2014 to July 2015 was conducted in a tertiary hospital medical intensive care unit in eastern Singapore, which has a tropical climate. All patients diagnosed with severe community-acquired pneumonia were included.ResultsA total of 117 patients were in the study. Microbial pathogens were identified in 84 (71.8%) patients. Mixed viral-bacterial co-infections occurred in 18 (15.4%) of patients. Isolated viral infections were present in 32 patients (27.4%); isolated bacterial infections were detected in 34 patients (29.1%). Hospital mortality occurred in 16 (13.7%) patients. The most common bacteria isolated was Streptococcus pneumoniae and the most common virus isolated was Influenza A. Univariate and multivariate logistic regression showed that serum procalcitonin, APACHE II severity score and mixed viral-bacterial infection were associated with increased risk of hospital mortality. Mixed viral-bacterial co-infections were associated with an adjusted odds ratio of 13.99 (95% CI 1.30–151.05, p = 0.03) for hospital mortality.ConclusionsRespiratory viruses are common organisms isolated in severe community-acquired pneumonia. Mixed viral-bacterial infections may be associated with an increased risk of mortality.

Host characteristics predict outcome among adult patients admitted by severe acute respiratory infection

“…Remarkably, in our setting different respiratory viruses were associated to admission in critical care units and to a case-fatality rate surpassing 10% of the cohort. These numbers replicate previous reports 8,16,17 and underline the significance of non-influenza respiratory besides influenza as agents capable of originate mortality, hospital admissions, and consumption of critical hospital resources among adult patients 3,5,7,8 .…”

“…Yet, recent studies have shown the relevance of viral pathogens among adult patients admitted for CAP with incidence rates surpassing those associated to bacterial microorganisms 5 . Respiratory syncytial virus and parainfluenza virus appear to be equally contributory than influenza infection to explain seasonal mortality in elderly persons in population studies, and other studies have indicated that viral-bacterial co-infection is more important than the specific virus involved to predict mortality among those admitted by pneumonia 16,17 . Thus, excepting pandemic conditions, it is not clear if seasonal influenza is associated with a higher death toll than other viral microorganisms or if different types and subtypes of influenza virus differs each other in mortality among admitted adult patients.…”

Factors predicting in‐hospital mortality among patients admitted with community acquired pneumonia at a tertiary care hospital Karachi, Pakistan

“…Viruses are also commonly isolated in CAP. Virus and bacterial coinfections are well established and associated with increased mortality in severe CAP . However, the identification of viruses and atypical pneumonia is not routinely done in our institution because of limitation of diagnostic facilities.…”

“…Virus and bacterial coinfections are well established and associated with increased mortality in severe CAP. 22,23 However, the identification of viruses and atypical pneumonia is not routinely done in our institution because of limitation of diagnostic facilities. Additionally, we do not have antigen detection testing available for streptococcus pneumonia which can affect the detection of streptococcus in our patient population.…”

An update on the detection methods of Parachlamydia acanthamoebae, an atypical agent of pneumonia

“…As such, it is possible that these animals could be efficient vectors or reservoirs as some of them are kept as pets by people while the remaining fall under the livestock category. (Akter et al, 2014;Aliberti et al, 2013;Caggiano et al, 2017;Capelastegui et al, 2012;Cillóniz et al, 2011;Farida et al, 2015;Holter et al, 2015;Huijskens et al, 2013;Jain et al, 2015;Köksal et al, 2010;Luchsinger et al, 2013;Lupisan et al, 2019;Mermond et al, 2010;Naik et al, 2010;Nascimento-Carvalho et al, 2016;Quah et al, 2018;Shibli et al, 2010;Spoorenberg et al, 2014;van Gageldonk-Lafeber et al, 2013).…”