Fluoroquinolone-Resistant Mycobacterium tuberculosis, Pakistan, 2005–2009

Household expenditure and tuberculosis prevalence in Vietnam: prediction by a set of household indicators. Quy HT, Diwan VK. Private pharmacies and tuberculosis control: a survey of case detection skills and reported anti-tuberculosis drug dispensing in private pharmacies in Ho Chi Minh City, Vietnam. Quy HT, Diwan VK. Private tuberculosis care provision associated with poor treatment outcome: comparative study of a semi-private lung clinic and the NTP in two urban districts in Ho Chi Minh City, Vietnam. To the Editor: Pakistan is 1 of 22 countries listed by the World Health Organization (WHO) as having a high incidence of tuberculosis (TB). We recently reported an increase in rates of multidrug-resistant (MDR) TB with emergence of extensively drug-resistant TB (1). Fluoroquinolone resistance is associated with worse outcome in patients with MDR TB (2). Recent evidence suggests emergence and increasing incidence of fl uoroquinolone-resistant Myco-bacterium tuberculosis from several countries, particularly in MDR strains (3). We present data from a tertiary care referral center laboratory in Pakistan to assess fl uoroquinolone resistance in MDR TB strains during 2005–2009. The Aga Khan University Hospital and its clinical laboratory have been accredited by the Joint Commission of International Accreditation and designated as a technical partner of the National TB Program. M. tuberculosis susceptibility testing is also periodically validated by the WHO Supranational Reference Laboratory network. The microbiology laboratory serves different cities across Pakistan with ≈180 peripheral collection units. Specimens for TB cultures are requested by physicians and received through passive collection and thus are not restricted to programmed surveys. All specimens received at each of the collection units are sent to the central laboratory in Karachi for culture and drug susceptibility testing (DST). Specimens reach the main laboratory within 24 hours after receipt. During the past 4 years, the laboratory has received 12,000– 15,000 specimens annually for M. tuberculosis culture; positivity rate has been 15%–20%. Culture and DST are performed at the laboratory in accordance with Clinical Laboratory Standards Institute and WHO recommendations, as described (4). During 2005–2008, fl uoroquinolone susceptibilities for all MDR and polydrug-resistant isolates were determined by using ciprofl oxacin (2 μg/mL). From 2009 onwards, fl uoroquinolone susceptibilities were determined by using ofl oxacin (2 μg/mL), and second-line DST was performed for all M. tuberculosis isolates. During 2005–2009, a total of 11,263 cultures were reported positive for M. tuberculosis. Of these, 34.4% were MDR, and 50.1% were sensitive to all 4 fi rst-line …