Article Text

Download PDFPDF

Outbreak of isoniazid resistant tuberculosis in north London
  1. M C Ruddy1,
  2. A P Davies2,
  3. M D Yates1,
  4. S Yates3,
  5. S Balasegaram8,
  6. Y Drabu2,
  7. B Patel2,
  8. S Lozewicz3,
  9. S Sen4,
  10. M Bahl5,
  11. E James6,
  12. M Lipman7,
  13. G Duckworth8,
  14. J M Watson8,
  15. M Piper9,
  16. F A Drobniewski1,
  17. H Maguire10
  1. 1HPA Mycobacterium Reference Unit, King’s College Hospital (Dulwich), Guy’s King’s and St Thomas’ Medical School, London SE22 8QF, UK
  2. 2North Middlesex University Hospital Trust, Medical Microbiology Department, London N18 1QX, UK
  3. 3North Middlesex University Hospital Trust, Respiratory Medicine, London N18 1QX, UK
  4. 4Enfield Primary Care Trust, Holbrook House, Barnet EN4 0DR, UK
  5. 5Islington Primary Care Trust, Insull Wing, London NW1 2LJ, UK
  6. 6Barnet and Chase Farm Hospital NHS Trust, Medical Microbiology Department, Barnet Hospital, High Barnet EN5 3DY, UK
  7. 7Royal Free Hospital NHS Trust, Respiratory Medicine, London NW3 2QG, UK
  8. 8HPA Communicable Disease Surveillance Centre, London NW9 5EQ, UK
  9. 9Prison Health, Department of Health, London Wellington House Task Force, London SE1 8UG, UK
  10. 10HPA Communicable Disease Surveillance Centre (London), London W2 3QR, and St George’s Hospital Medical School, London SW17 0QT, UK
  1. Correspondence to:
    Dr M C Ruddy
    HPA Mycobacterium Reference Unit, King’s College Hospital (Dulwich), Guy’s King’s and St Thomas’ Medical School, London SE22 8QF, UK;


Background: A description is given of a major outbreak of isoniazid monoresistant tuberculosis (TB) chiefly in north London, including prisons. The earliest case was diagnosed in 1995 with most cases appearing after 1999.

Methods: Confirmation of a local cluster of cases was confirmed by restriction fragment length polymorphism (RFLP IS6110) typing or “rapid epidemiological typing” (RAPET). Further cases were found by retrospective analysis of existing databases, prospective screening of new isolates, and targeted epidemiological case detection including questionnaire analysis.

Results: By the end of 2001, 70 confirmed cases in London had been linked with a further 13 clinical cases in contacts and nine epidemiologically linked cases outside London. The epidemic curve suggests that the peak of the outbreak has not yet been reached. Cases in the outbreak largely belong to a social group of young adults of mixed ethnic backgrounds including several individuals from professional/business backgrounds. Compared with other cases of TB reported to the enhanced surveillance scheme in London during 1999–2001, the cases are more likely to be of white (26/70 (37%) v 1308/7666 (17%)) or black Caribbean ethnicity (17/70 (24%) v 312/7666 (4%)), born in the UK (41/70 (59%) v 1335/7666 (17%)), and male (52/70 (74%) v 4195/7666 (55%)). Drug misuse and/or prison detention are factors common to many cases.

Conclusions: The investigation of the outbreak revealed significant problems on an individual patient and population based level including difficulties with contact tracing, compliance, and the risk of developing multidrug resistance. This incident has demonstrated the value of molecular strain typing in investigating an extensive outbreak of TB. This is the first documented outbreak involving a UK prison.

  • tuberculosis
  • isoniazid
  • resistance
  • prison
  • tuberculosis transmission
View Full Text

Statistics from


    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

    Linked Articles

    • airwaves
      Wisia Wedzicha