We conducted a case-control study to examine risk factors for isoniazid-monoresistant Mycobacterium tuberculosis in an ongoing outbreak in London. Cases were defined as individuals with an isoniazid-monore- sistant strain diagnosed from 1995 to the third quarter of 2006 with an indistinguishable restriction fragment length polymorphism (RFLP) or mycobacterial inter- spersed repetitive unit (MIRU)-variable number tan- dem repeats (VNTR) pattern who were resident in or had epidemiological links with London. Controls were all other individuals reported with tuberculosis to the Health Protection Agency London regional epidemiol- ogy unit or the HPA London TB Register during 2000 to 2005. Of 293 cases, 153 (52%) were sputum smear- positive compared with 3,266 (18%) of controls. Cases were more likely to be young adults (aged between 15 and 34 years), born in the United Kingdom (OR: 2.4; 95% CI: 1.7-3.4) and of white (OR: 2.9; 95% CI: 1.8- 4.8) or black Caribbean (OR: 12.5; 95% CI: 7.7-20.4) ethnicity, a prisoner at the time of diagnosis (OR: 20.2; 95% CI: 6.7-60.6), unemployed (OR: 4.1; 95% CI: 3.0- 5.6), or a drug dealer or sex worker (OR: 187.1; 95% CI: 28.4-1,232.3). A total of 113 (39%) of cases used drugs and 54 (18%) were homeless. Completion of treatment gradually improved in cases from 55% among those diagnosed up to the end of 2002 compared with 65% by the end of 2006. Treatment completion increased from 79% to 83% in controls from 2000 to 2005. There are complex social challenges facing many cases in this outbreak that need to be addressed if medical interventions are to be successful.
|Publication status||Published - 31 Mar 2011|