Epidemiology and Infection

The molecular epidemiology of tuberculosis in inner London

A. C.  HAYWARD  a1 c1, S.  GOSS  a2, F.  DROBNIEWSKI  a2, N.  SAUNDERS  a3, R. J.  SHAW  a4, M.  GOYAL  a5, A.  SWAN  a6, A.  UTTLEY  a2, A.  POZNIAK  a7, J.  GRACE-PARKER  a8 and J. M.  WATSON  a8
a1 PHLS Communicable Disease Surveillance Centre – London/University College London, Centre for Infectious Disease Epidemiology, London
a2 PHLS Mycobacterium Reference Unit, Dulwich, London
a3 PHLS Virus Reference Division, Central Public Health Laboratories, London
a4 Director of Medicine and Professor of Respiratory Medicine, Hammersmith Hospitals NHS Trust, London
a5 Department of Respiratory Medicine, NHLI, ICSM London
a6 PHLS Statistics Unit, London
a7 Department of GUM/HIV Medicine, Chelsea and Westminster Hospital, London
a8 PHLS Communicable Disease Surveillance Centre, London


The study used DNA fingerprint typing (spoligotyping and Heminested-Inverse-PCR) of Mycobacterium tuberculosis from all culture-confirmed inner London patients over a 12-month period to describe transmission. The methodology was evaluated by comparison with standard IS6110 typing and by examining its ability to identify known household clusters of cases. Isolates sharing indistinguishable typing patterns using both techniques were defined as clustered. Clusters were investigated to identify epidemiological links. The methodology showed good discriminatory power and identified known household clusters of cases. Of 694 culture-confirmed cases, 563 (81%) were typed. Eleven (2%) were due to laboratory cross-contamination and were excluded. Of the remaining 552 isolates 148 (27%) were clustered. Multivariate analysis indicated that clustering was more common in those with pulmonary smear positive disease (P<0·02); those born in the United Kingdom (P<0·0003) and in patients living in south London (P = 0·02). There was also a trend towards clustering being more common in those not known to have HIV infection (P = 0·051). The results suggest that in inner London, recent local transmission makes an important contribution to notification rates.

(Accepted November 19 2001)

c1 Author for correspondence.