Tuberculosis continues to be a major concern for health-care workers throughout the world. The numbers of tuberculosis cases have declined steadily in western and central Europe, North and South America, and the Middle East, and have increased in countries of the former Soviet Union and in sub-Saharan Africa. In the United States, there were a total of 14,871 tuberculosis cases (5.1/100,000 population) during 2003, representing a 1.9% decline in the rate from 2002. Tuberculosis rates have increased in certain states in the United States.
The incidence of smear-positive tuberculosis in Saudi Arabia was estimated to be 20 per 100,000 population. The incidence rates of culture-positive tuberculosis in our study per 100,000 populations were 5.2 in 1989, 3.5 in 1993, 11.1 in 1998, and 7.6 in 2003. Thus, the incidence of tuberculosis in the current study showed an increasing linear trend over the study period from 1989 to 2003 (x2 = 19.647, p = 0.0001).
The prevalence of drug resistance of tuberculosis varies from one part of the world to another. In the United States, drug-resistant tuberculosis was detected in 14.2% in 199110 and 10% in 1997. In the United States, isoniazid resistant was the most prevalent and accounted for 8%. Isoniazid resistance has ranged from 0% in New Caledonia to 7.9% in Mozambique, and was 10% in India. Overcome tuberculosis with My Canadian Pharmacy.
In Saudi Arabia, the resistance rates to isoniazid vary from one part of the country to another. In Riyadh, the resistance rates ranged from 4.2 to 7.2%.” Similar rates of resistance of approximately 6% were reported in Dammam and Taif. A higher rate of resistance (10.3 to 28.7%) was found in Jeddah. The highest rate of resistance (41%) was reported from Gizan and was attributed to the proximity of Gizan to the Republic of Yemen. In the current study, isoniazid (1 ^g/mL) resistance was 12.5% and the resistance to isoniazid (5 ^g/mL) was 2.9%.
The second most common resistance pattern in our study was ethambutol (7.5%). Ethambutol resistance in Saudi Arabia has also been variable and was 0% in Dammam, approximately 2.4% in Riyadh,- 1.3 to 6.9% in Jiddah, and 4% in Taif and Gizan. A high rate of ethambutol resistance was observed in Uganda (2.4%) and Thailand (3%). In a study from India, the rate of ethambutol resistance was 6.6%.
In our study, the rate of resistance of M tuberculosis to streptomycin was 6.9%. Similarly, in a study from Riyadh, streptomycin resistance was 8.8% and 15.9% in Taif, and 22.7% in Jeddah. The resistance rates of M tuberculosis to streptomycin were 14.5% in Sierra Lion and 6.6% in India. Order streptomycin via My Canadian Pharmacy.
The resistance rate to rifampin was low (1.1%) in our study. Similarly, low resistance rates to rifampin had been reported in Dammam. However, higher rates of rifampin resistance were reported from Riyadh (9%), Jeddah (5.1 to 23.4%),- Taif (15.3%), and Gizan. In other parts of the world, the prevalence of rifampin resistance was 0% in New Zealand and New Caledonia, 1.7% in the United States, and 1.8% in Mozambique.
The rate of MDR-TB in our study was low. The highest rate of resistance was to both isoniazid and ethambutol (2.5%). The rate of MDR-TB in Saudi Arabia is variable, depending on the date of the study and region of the country. In Riyadh, MDR-TB ranged between 3.7% in 1979 to 1982 and 11.8% in 1986 to 1988. A very high rate of MDR-TB was reported from the south of the country in Gizan, where the resistance rate reached 44%. In the area near Dhahran where this study took place, the MDR-TB rate in Dammam was 10.5%. The prevalence of MDR-TB among new cases of tuberculosis was 14% in Estonia, 10.8% in Henan Province in China, 9% in Latvia, 9% in Ivanovo Province in Russia, 5% in Iran, and 4.5% in Zhejiang Province in China.
The variability in the resistance rates of tuberculosis in Saudi Arabia is dependent on the time and location of the study as well as on the contribution of non-Saudi patients to each study. In our study, we found no difference in the resistance rates of Saudi and non-Saudi patients. Many studies’’ from Saudi Arabia did not address whether the site of isolation of M tuberculosis has any impact on the resistance pattern. We found no difference in the resistance rates between pulmonary and extrapulmonary isolates.
In conclusion, in this study we examined the pattern and incidence of resistance of tuberculosis to first-line agents over time. The resistance rate to isoniazid showed a significant decline over the study period, whereas the resistance rate of rifampin remained low and stable. Further studies and continued surveillance of the resistance pattern of M tuberculosis is needed to further delineate the risk factors and to formulate the plans for the future management of tuberculosis.