Secular trends in susceptibility patterns of Mycobacterium tuberculosis isolates in Kuwait, 1996-2005

OBJECTIVE: To determine the incidence and trends of drug resistance among all Mycobacterium tuberculosis strains isolated during a 10-year period in Kuwait. DESIGN: Drug susceptibility data for M. tuberculosis isolates recovered from all pulmonary and extra-pulmonary tuberculosis (TB) patients in Kuwait from January 1996 to December 2005 were collected and analysed. Patients were divided into Kuwaiti nationals and expatriates. Prior treatment status was not recorded. RESULTS: From 1996 to 2005, 5399 non-repetitive culture-positive TB cases (56% from pulmonary sites and 44% from extra-pulmonary sites) among 917 (17%) Kuwaiti nationals and 4482 (83%) expatriates were identified throughout Kuwait. Overall resistance rates were as follows: any drug 12.5%, isoniazid (INH) 9.1%; rifampicin (RMP) 1.1%, ethambutol (EMB) 2.0%, streptomycin 4.3% and multidrug resistance (MDR) 0.9%. The resistance rates over the 10-year period remained nearly same. However, significant differences were noted in resistance rates for RMP and MDR among pulmonary vs. extra-pulmonary cases and for any drug, INH and EMB among isolates from Kuwaiti vs. expatriate patients. CONCLUSIONS: Moderate and stable single drug resistance (< 10%) and low MDR rates (< 1%) were found among TB cases in Kuwait. These findings highlight the importance of ongoing control measures to limit the development and spread of drug-resistant M. tuberculosis in Kuwait.