Meningococcal bacterial DNA load at presentation correlates with disease severity
- 1Institute of Child Health, Alder Hey Children's Hospital, Eaton Road, Liverpool L12 2AP, UK
- 2PHLS Meningococcal Reference Unit (MRU), Withington Hospital, Manchester M20 2LR, UK
- 3Department of Medical Microbiology, Duncan Building, Liverpool University, Daulby Street, Liverpool L69 3GA, UK
- Correspondence to:
Dr S J Hackett, Institute of Child Health, Alder Hey Children's Hospital, Eaton Road, Liverpool LI2 2AP, UK;
scott.hackett{at}liv.ac.uk
- Accepted 13 August 2001
Abstract
Aims: To determine bacterial loads in meningococcal disease (MCD), their relation with disease severity, and the factors which determine bacterial load.
Methods: Meningococcal DNA quantification was performed by the Taqman PCR method on admission and sequential blood samples from patients with MCD. Disease severity was assessed using the Glasgow Septicaemia Prognostic Score (GMSPS, range 0–15, severe disease ≥8).
Results: Median admission bacterial load was 1.6 × 106 DNA copies/ml of blood (range 2.2 × 104 to 1.6 × 108). Bacterial load was significantly higher in patients with severe (8.4 × 106) compared to milder disease (1.1 × 106, p = 0.018). This difference was greater in septicaemic patients (median 1.6 × 107 versus 9.2 × 105, p < 0.001). Bacterial loads were significantly higher in patients that died (p = 0.017). Admission bacterial load was independent of the duration of clinical symptoms prior to admission, with no difference between the duration of symptoms in mild or severe cases (median, 10.5 and 11 hours respectively). Bacterial loads were independent of DNA elimination rates following treatment.
Conclusion: Patients with MCD have higher bacterial loads than previously determined with quantitative culture methods. Admission bacterial load is significantly higher in patients with severe disease (GMSPS ≥8) and maximum load is highest in those who die. Bacterial load is independent of the duration of clinical symptoms or the decline in DNA load.
