Anti-tuberculosis drug resistance and associated risk factors in a tertiary level TB center in Iran: a retrospective analysis

Abstract

Introduction: This study aimed to determine first-line anti-tuberculosis drug resistance rates in new and previously treated cases and to identify risk factors associated with multidrug resistant tuberculosis (MDR-TB) at the National Reference Tuberculosis Laboratory of Iran. Methodology: This was a retrospective analysis of all confirmed TB patients from December 2000 to June 2005. Drug susceptibility testing to isoniazid, rifampicin, streptomycin, ethambutol and pyrazinamide was performed on Löwenstein-Jensen (LJ) medium according to the proportion method. Results: Mycobacterium tuberculosis strains were isolated from 1,742 patients with TB, of whom 935 (53.7%) were male. The mean age of patients was 44.2 ± 17.4 years (SD). A total of 1,074 patients were native Iranians while 668 (38.3%) were immigrant patients. Out of 1,139 (65.4%) new cases, 340 (29.9%) had at least one drug resistance. Of 603 (34.6%) previously treated cases, 416 (69.0%) had resistant strains. There were 263 patients (15.1%) with MDR-TB, 72 of whom were new (6.3% of all new cases) and 191 were previously treated (31.7% of all previously treated cases). Factors associated with MDR-TB included age under 45 years, male sex, previous TB treatment, immigration, poor living conditions, and unemployment. Conclusions: The high rate of initial resistance in MDR-TB cases and the high rate of MDR-TB in a young age group were indicators of recent transmission. Therefore, closer monitoring of transmission trends of drug resistant strains should be considered as priority, to ensure a successful TB control programme.

Risk factors for multidrug resistant tuberculosis patients in Amhara National Regional State.

“…History of TB treatment failure was one of the strongest predictors for having MDR-TB. This conforms to other studies conducted in different parts of the world 14,[17][18][19][20][21] . Similarly, a nationwide anti-TB drug resistance survey conducted Key: ANRS (Amhara National Regional State), COR (Crude odds ratio), AOR (Adjusted odds ratio)…”

“…The association between TB treatment failure and MDR-TB might be related to unsatisfactory compliance by patients or clinicians, lack of supervision of treatment, improper drug regimens and inadequate or irregular drug supply that may potentiate drug resistance 14,[17][18][19][20][21] . Furthermore, those TB patients who had history of > 2 times anti TB treatment were 1.9 times more likely to be at risk of developing MDR-TB.…”

Mycobacterium tuberculosis Complex Drug Resistance in a High Tuberculosis Incidence Area from the WHO Eastern Mediterranean Region

“…These findings are consistent with lower values of previous reports from Iran ranging from 7.8-27% for STM and 1.9-23% for INH (24)(25)(26)(27). There are reports from Pakistan, Turkey and Iraq indicating 0-16.1% resistance to STM and 8.9-18.9% to INH (18)(19)(20).…”

“…This high rate of STM resistance has considerably significant impact on TB control strategies as it is often used as secondline drugs for TB treatment in Iran. As a consequence, the treatment regimens might be less effective due to the effectiveness of STM (25,29,30). Salek et al (31) studied the incidence of pulmonary TB in different ethnic groups residing in Golestan province from 1999-2003 and reported that 45% of TB patients belonged to Sistani, followed by Persian (22%), Turkmen (19%) and Baluch (9%) ethnicity.…”

Primary ethambutol resistance among Iranian pulmonary tuberculosis patients: a systematic review

“…The incidence rate of TB in Iran, which is located between high TB-burden countries, was 22 cases per 100,000 people in the year 2014 [WHO, 2015]. Studies from Iran have also shown that primary resistance rates of M. tuberculosis to INH and RIF vary widely, that is, from 10% to 40% [Merza et al 2011;Velayati et al 2014;Nasiri et al 2016]. However, little is known about the prevalence of EMB-resistant TB in Iran.…”