Epidemiology of antituberculosis drug resistance in Saudi Arabia: findings of the first national survey.

The real magnitude of antituberculosis (anti-TB) drug resistance in Saudi Arabia is still unknown because the available data are based on retrospective laboratory studies that were limited to hospitals or cities. A representative national survey was therefore conducted to investigate the levels and patterns of anti-TB drug resistance and explore risk factors. Between August 2009 and July 2010, all culture-positive TB patients diagnosed in any of the tuberculosis reference laboratories of the country were enrolled. Isolates obtained from each patient were tested for susceptibility to first-line anti-TB drugs by the automated Bactec MGIT 960 method. Of the 2,235 patients enrolled, 75 cases (3.4%) were lost due to culture contamination and 256 (11.5%) yielded nontuberculous mycobacteria (NTM). Finally, 1,904 patients (85.2% of those enrolled) had available drug susceptibility testing results. Monoresistance to streptomycin (8.1%; 95% confidence interval [CI], 7.2 to 9.1), isoniazid (5.4%; 95% CI, 4.7 to 6.2), rifampin (1%; 95% CI, 0.7 to 1.3) and ethambutol (0.8%; 95% CI, 0.5 to 1.2) were observed. Multidrug-resistant TB (MDR-TB) was found in 1.8% (95% CI, 1.4 to 2.4) and 15.9% (95% CI, 15.4 to 16.5) of new and previously treated TB cases, respectively. A treatment history of active TB, being foreign-born, having pulmonary TB, and living in the Western part of the country were the strongest independent predictors of MDR-TB. Results from the first representative national anti-TB drug resistance survey in Saudi Arabia suggest that the proportion of MDR-TB is relatively low, though there is a higher primary drug resistance. A strengthened continuous surveillance system to monitor trends over time and second-line anti-TB drug resistance as well as implementation of innovative control measures, particularly among immigrants, is warranted.

Current trends of Mycobacterium tuberculosis molecular epidemiology in Saudi Arabia and associated demographical factors.

Data are scarce on demographical factors related to the population structure of Mycobacterium tuberculosis in Saudi Arabia. A study was conducted on 902 clinical isolates to explore current trends in the phylogeography and associated demographical factors of tuberculosis by using spoligotyping and 24 loci based MIRU-VNTR typing. Young male patients (aged 16-29 and 30-44) were predominant in this cohort. The phylogenetic diversity among M. tuberculosis isolates was found high, as almost all known genetic lineages were identified. Delhi/CAS (26.4%), EAI (13.7%) and Haarlem (11.3%) were the most common lineages observed, particularly among the low age groups (16-29 and 30-44 years), whereas elderly patients (>60 years) showed a predominance in the lineages S, Ghana, TUR and Uganda-I. A statistically significant association was observed between gender of the patients and lineages of EAI (p value 0.026) and LAM (p value 0.005). Overall, molecular strain cluster rate was 34.4% with an elevated rate among patients aged below 15 years (43.1%), while cases among the elderly (>60 years) showed the lowest degree of clustering (12.5%). The largest level of clustering was noticed among cases caused by strains of the lineages Haarlem (59.8%), Beijing (55.8%) and LAM (42.8%). The current population structure of M. tuberculosis in Saudi Arabia is highly diverse with significant associations to demography, transmission dynamics and origin of the patients. The difference in genotype distributions among low and high aged patients reflects the ongoing change in the strain population structure in the country.

The Saudi Thrombosis and Familial Thrombophilia Registry. Design, rational, and preliminary results.

OBJECTIVE: To describe the Registry and report preliminary data for the prevalence of 5 prothrombotic gene mutations in the normal Saudi population. METHODS: Blood from consenting healthy Saudi individuals and patients with venous thrombosis (VT) from different regions of the Kingdom was collected from November 2001 until July 2007. The extracted DNA of each sample was kept at -70 degrees C until tested for 5 known prothrombotic factors using established methods. Only patients with confirmed VT were included. Data generated through direct interview were entered into the Saudi Thrombosis and Familial Thrombophilia (S-TAFT) Register. The consent and demographic data collection forms and the S-TAFT Register were developed using the SQL web based software. RESULTS: Nine hundred and two DNA samples of consenting healthy Saudi individuals were tested for factor V Leiden (FVL), prothrombin (PT) 20210 G>A, 5-10 methylenetetrahydrofolate reductase (MTHFR) 677 C>T, the 4G/5G polymorphism of Plasminogen activator inhibitor type 1 (PAI-1 4G/5G), and factor V HR2 (FVHR2) haplotype. The incidence of FVL among healthy subjects was 1.3%, PT 20210 G>A 0.7%, homozygous MTHFR 677C>T 2.45%, PAI 4G/4G 10.1%, and FVHR2 26.1%. CONCLUSION: Our preliminary data from healthy Saudi individuals suggest that the incidence of the 5 prothrombotic risk factors is lower than in most other populations, except for FVHR2.