Pneumococcal colonisation density: a new marker for disease severity in HIV-infected adults with pneumonia

• Type of Material: Article
• Authors: Werner C Albrich, Kantonsspital St Gallen; Shabir A Madhi, University of Witwatersrand; Peter V Adrian, University of Witwatersrand; Nadia van Niekerk, University of Witwatersrand; Jean-Noel Telles, Fondation Mérieux; N Ebrahim, University of Witwatersrand; Melina Messaoudi, Fondation Mérieux; Glaucia Paranhos-Baccala, Fondation Mérieux; Sven Giersdorf, Thermo Sci Biomarkers; Guy Vernet, Fondation Mérieux; Beat Mueller, Kantonsspital Aarau; Keith Klugman, Emory University
• Language: English
• Date: 2014-08-09
• Publisher: BMJ Publishing Group: Open Access
• Publication Version: Final Published Version
• Copyright Statement: Published by the BMJ Publishing Group Limited.
• License: Creative Commons Attribution-NonCommercial 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1136/bmjopen-2014-005953
• Title of Journal or Parent Work: BMJ Open
• ISSN: 2044-6055
• Volume: 4
• Issue: 8
• Start Page: e005953
• End Page: e005953
• Grant/Funding Information: This work was funded by the Center for AIDS Research/NIH Grant P30 A1050409 to KPK; C-polysaccharide Antigen was provided free of charge by Binax; PCT sensitive LIA, MR-proADM KRYPTOR, MR-proANP KRYPTOR, Copeptin KRYPTOR were provided free of charge by Thermo Scientific Biomarkers, Hennigsdorf, Germany.
• Keywords: BACTEREMIA; MEDICINE, GENERAL & INTERNAL; TIME; RESPIRATORY-TRACT INFECTIONS; MORTALITY; ANTIBIOTIC-RESISTANCE; BACTERIAL LOAD; Science & Technology; CLINICAL PRESENTATION; SOUTH-AFRICA; Life Sciences & Biomedicine; General & Internal Medicine; COMMUNITY-ACQUIRED PNEUMONIA; STREPTOCOCCUS-PNEUMONIAE; Medicine, General & Internal
• Research Categories: Health Sciences, Epidemiology; Health Sciences, Medicine and Surgery; Health Sciences, Pathology

Abstract

Objective A high genomic load of Pneumococcus from blood or cerebrospinal fluid has been associated with increased mortality. We aimed to analyse whether nasopharyngeal colonisation density in HIV-infected patients with community-acquired pneumonia (CAP) is associated with markers of disease severity or poor outcome. Methods Quantitative lytA real-time PCR was performed on nasopharyngeal swabs in HIV-infected South African adults hospitalised for acute CAP at Chris Hani Baragwanath Hospital, Soweto, South Africa. Pneumonia aetiology was considered pneumococcal if any sputum culture or Gram stain, urinary pneumococcal C-polysaccharide-based antigen, blood culture or whole blood lytA real-time PCR revealed pneumococci. Results There was a moderate correlation between the mean nasopharyngeal colonisation densities and increasing CURB65 scores among all-cause patients with pneumonia (Spearman correlation coefficient r=0.15, p=0.06) or with the Pitt bacteraemia score among patients with pneumococcal bacteraemia (p=0.63). In patients with pneumococcal pneumonia, nasopharyngeal pneumococcal colonisation density was higher among non-survivors than survivors (7.7 vs 6.1 log10 copies/mL, respectively, p=0.02) and among those who had pneumococci identified from blood cultures and/or by whole blood lytA real-time PCR than those with non-bacteraemic pneumococcal pneumonia (6.6 vs 5.6 log10 copies/mL, p=0.03). Nasopharyngeal colonisation density correlated positively with the biomarkers procalcitonin (Spearman correlation coefficient r=0.37, p<0.0001), proadrenomedullin (r=0.39, p=0.008) and copeptin (r=0.30, p=0.01). Conclusions In addition to its previously reported role as a diagnostic tool for pneumococcal pneumonia, quantitative nasopharyngeal colonisation density also correlates with mortality and prognostic biomarkers. It may also be useful as a severity marker for pneumococcal pneumonia in HIV-infected adults.