Role of atypical pathogens in hospitalized adults with community-acquired pneumonia

Abstract number: O572

Ratchina S., Shal E., Kozlov R., Kretchikova O., Ivanchik N., Ustjuzhanin I., Yatsyshina S., Astakhova T., Kondratieva T., Beykin Ya., Besedina L.

Background: CAP can be caused by a broad spectrum of bacterial pathogens. Appropriate antimicrobial therapy is based on knowledge of common causative agents. Incidence of atypical causative agents of CAP may interfere in treatment choice.

Objectives: To investigate the frequency of atypical pathogens in hospitalized adults with CAP in Smolensk region.

Methods: A prospective study on adult patients with CAP in various Smolensk city hospitals was performed in 2007. Pretreatment respiratory specimens were obtained for routine culture and DNA based polymerase chain reaction (PCR) for the detection of Legionella pneumophila (L.p.), Mycoplasma pneumoniae (M.p.) and Chlamydophila pneumoniae (C.p.). Acute phase and reconvalescent serum samples were collected for the detection of specific IgM and IgG antibodies of L.p., M.p., C.p. by ELISA in accordance with manufacturer's manual [1]. Multiple logistic regression analysis was used to identify independent risk factors (age, CAP severity, presence of complications, significant comorbidities, etc.) of infection with atypical pathogens.

Results: Overall, 295 patients aged from 18 to 87 years, mean age 43.0±19.9 years, 80.7% males, were enrolled. PCR was positive in 57/295 (19.3%) of cases: M.p. – 47/295 (14.9%), C.p. – 5/295 (1.7%), L.p. – 5/295 (1.7%) and M.p. with C.p. – 3/295 (1%). Causative agents were revealed by routine culture in 78/295 (26.4%) of cases. Both PCR and serological tests were performed in 112/295 (38%) of patients. The results coincided in 44/112 (39.3%) of cases; 24/26 (92.3%) of PCR positive cases were confirmed by serologic tests, serology yielded positive results for 18/109 (16.6%), 29/110 (26.4%) and 50/91 (54.9%) PCR negative L.p., C.p. and M.p. samples. Absence of complications and serious comorbidities were only independent variables predicting the high risk of M.p. and M.p. + C.p. infection.

Conclusions: Atypical bacteria (especially M.p.) are rather common causative agents of CAP in hospitalized adults in Smolensk region. The risk of M.p. and/or C.p. infection is increased in uncomplicated CAP cases and patients without serious concomitant diseases. ELISA doesn't seem to be a reliable test for identification of atypical bacterial pathogens.


1. Sero MPTM IgM, Sero MPTM IgG, Sero CPTM IgM and Sero CPTM IgG, Savyon Diagnostics; Legionella pneumophila Serogroup 1 ELISA IgM and IgG, Vircell, s.1.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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