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

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.

• Authors: Werner C Albrich, Shabir A Madhi, Peter V Adrian, Nadia van Niekerk, Jean-Noel Telles, N Ebrahim, Melina Messaoudi, Glaucia Paranhos-Baccalà, Sven Giersdorf, Guy Vernet, Beat Mueller, Keith P Klugman
• Journal: BMJ open (BMJ Open) Vol. 4 Issue 8 Pg. e005953 (Aug 11 2014) ISSN: 2044-6055 [Electronic] England
• PMID: 25113557 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Chemical References

• Biomarkers
• CALCA protein, human
• Protein Precursors
• proadrenomedullin
• Adrenomedullin
• Calcitonin
• Calcitonin Gene-Related Peptide

Topics

• Adolescent
• Adrenomedullin (blood)
• Adult
• Bacteremia (microbiology)
• Biomarkers (blood)
• Calcitonin (blood)
• Calcitonin Gene-Related Peptide
• Community-Acquired Infections (complications, microbiology)
• HIV Infections (complications)
• Hospitalization
• Humans
• Nasopharynx (microbiology)
• Pneumonia
• Pneumonia, Pneumococcal (complications, microbiology)
• Protein Precursors (blood)
• Real-Time Polymerase Chain Reaction
• Severity of Illness Index
• South Africa
• Streptococcus pneumoniae (growth & development)