Etiology of community-acquired pneumonia and diagnostic yields of microbiological methods: a 3-year prospective study in Norway

Abstract

BackgroundDespite recent advances in microbiological techniques, the etiology of community-acquired pneumonia (CAP) is still not well described. We applied polymerase chain reaction (PCR) and conventional methods to describe etiology of CAP in hospitalized adults and evaluated their respective diagnostic yields.Methods267 CAP patients were enrolled consecutively over our 3-year prospective study. Conventional methods (i.e., bacterial cultures, urinary antigen assays, serology) were combined with nasopharyngeal (NP) and oropharyngeal (OP) swab samples analyzed by real-time quantitative PCR (qPCR) for Streptococcus pneumoniae, and by real-time PCR for Mycoplasma pneumoniae, Chlamydophila pneumoniae, Bordetella pertussis and 12 types of respiratory viruses.ResultsEtiology was established in 167 (63%) patients with 69 (26%) patients having ≥1 copathogen. There were 75 (28%) pure bacterial and 41 (15%) pure viral infections, and 51 (19%) viral–bacterial coinfections, resulting in 126 (47%) patients with bacterial and 92 (34%) patients with viral etiology. S. pneumoniae (30%), influenza (15%) and rhinovirus (12%) were most commonly identified, typically with ≥1 copathogen. During winter and spring, viruses were detected more frequently (45%, P=.01) and usually in combination with bacteria (39%). PCR improved diagnostic yield by 8% in 64 cases with complete sampling (and by 15% in all patients); 5% for detection of bacteria; 19% for viruses (P=.04); and 16% for detection of ≥1 copathogen. Etiology was established in 79% of 43 antibiotic-naive patients with complete sampling. S. pneumoniae qPCR positive rate was significantly higher for OP swab compared to NP swab (P<.001). Positive rates for serology were significantly higher than for real-time PCR in detecting B. pertussis (P=.001) and influenza viruses (P<.001).ConclusionsEtiology could be established in 4 out of 5 CAP patients with the aid of PCR, particularly in diagnosing viral infections. S. pneumoniae and viruses were most frequently identified, usually with copathogens. Viral–bacterial coinfections were more common than pure infections during winter and spring; a finding we consider important in the proper management of CAP. When swabbing for qPCR detection of S. pneumoniae in adult CAP, OP appeared superior to NP, but this finding needs further confirmation.Trial registrationClinicalTrials.gov Identifier: NCT01563315.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-015-0803-5) contains supplementary material, which is available to authorized users.

Viral infection in community-acquired pneumonia: a systematic review and meta-analysis

“…Studies that met all the reporting criteria set in our risk of bias assessment were considered of low risk of bias. Analysis of these studies showed a proportion of viral infection of 22.6% (95% CI 18.7-26.5%; I 2 =92.6%) [2,3,7,10,12,17,18,22,23,25,28,29,31,35].…”

“…In patients with dual bacterial and viral infection (10 studies), the odds of death were significantly higher compared with patients without dual infection (OR 2. [3] SAITO [32] HOLM [22] JENNINGS [8] HOHENTHAL [21] CHARLES [17] JOHNSTONE [27] DIEDEREN [20] MERMOND [7] SHIBLI [34] JOHANSSON [26] LIEBERMAN [30] HARA [6] CILLÓNIZ [18] CHOI [2] SANGIL [33] YIN [36] VAN GAGELDONK-LAFEBER [5] LUCHSINGER [9] TAKAHASHI [10] WIEMKEN [11] MUSHER [12] VIASUS [35] HUIJSKENS [24] KIM [29] KARHU [28] HOLTER [23] QU [31] DAS [19] JAIN [25] …”

En mann i 50-årene med feber og anemi

“…I to norske studier fant man at henholdsvis 2 % og 4 % av samfunnservervede pneumonier som krevde sykehusinnleggelse skyldtes M. pneumoniae (8,9). M. pneumoniae-infeksjon kan i sjeldne tilfeller i tillegg til autoimmun hemolytisk anemi gi nevrologiske komplikasjoner som encefalitt, myelitt, Guillain-Barrés/Miller-Fishers syndrom og kan ha kardiologiske manifestasjoner som perimyokarditt samt hudmanifestasjoner (10,11).…”

Serotype Replacement in Adult Pneumococcal Pneumonia after the Introduction of Seven-Valent Pneumococcal Conjugate Vaccines for Children in Japan: a Systematic Literature Review and Pooled Data Analysis

“…Recent studies from Europe reported that approximately 30 of pneumonia cases resulted from a pneumococcal infection (2,4). Our previously published multicenter prospective study showed that pneumococcus was detected in 26.2 of all community-onset pneumonia cases, and the estimated incidence of adult pneumococcal pneumonia in Japan was 473 cases per 100,000 person-years (PYs) (1).…”

“…Streptococcus pneumoniae (pneumococcus) is one of the most common causative agents for adult pneumonia (1)(2)(3)(4). Recent studies from Europe reported that approximately 30 of pneumonia cases resulted from a pneumococcal infection (2,4).…”