R629 Publication Only Clinical ID: Mycobacterial infections (including diagnosis) Drug resistance of complex strains of Mycobacterium tuberculosis isolated at a tertiary referral teaching hospital in Istanbul, Turkey O. Baylan1, B. Bektore1, B. Selek1, T. Kula Atik1, M. Ozyurt1 1Medical Microbiology, Gulhane Military Medical Academy Haydarpasa Training Hospital, Istanbul, Turkey

Objectives: Increasing number of drug resistant tuberculosis (TB) cases, especially multi-drug resistance (MDR), observed in recent years, is an important global public health problem. The study was designed to investigate the drug resistance (DR) rates of Mycobacterium tuberculosis complex (MTC) strains, isolated in the mycobacteriology laboratory of a tertiary referral hospital in a TB endemic region.

Methods: In this retrospective study, it was aimed to evaluate the DR rates of 79 MTC strains first-line anti-TB drugs (streptomycin, isoniazid [INH], rifampicin [RMP], ethambutol), isolated from 2196 TB suspected patients in our hospital between January 2012 to November 2013. Susceptibility testing of isolates for the first-line anti-TB drugs was performed by using modified Middlebrook 7H9 broth in fluorometric BACTEC MGIT 960 system (Becton Dickinson, USA). Poly-drug resistance (PDR) was defined as resistance to two or more first-line drugs, whereas MDR was defined as resistance to at least INH and RMP.

Results: We tested 3614 specimens obtained from 2196 patients. A total of 369 specimens from 79 patients were found to contain MTC. We detected that 74.7% of isolates (n=59) were susceptible to all four major drugs, whereas 25.3% of isolates were resistant to at least one drug. Two isolates were resistant to all four drugs (2.5%), eight isolates were otherwise MDR (10.1%) and 11 isolates were resistant to a single drug (13.9%). Single DR was mainly due to INH (n=8, 10.1%). PDR other than MDR occurred in one (1.3%) isolates.

Conclusions: Detection of eight MDR isolates including two strains resistant to all first-line anti-TB drugs indicated the need for second-line anti-TB drug testing to reveal extensively drug resistance (XDR) TB isolates. We suggest that strict measures such as 'directly observed therapy' should be undertaken in order to prevent development of DR. Regular and continuous screening of anti-TB DR should be accomplished to survey the presence of drug resistant strains in the nation, to define the suitable drug regimens and to evaluate the quality of TB control programs.