Beijing strains of Mycobacterium tuberculosis in smear-positive tuberculosis patients in North-West and West of Iran

Role of Immigration in Tuberculosis Transmission to Iran: A Systematic Review

Background:

Today, because of increasing immigration and the prevalence of drug-resistant tuberculosis in Iran, identifying intra-community cases is necessary in the country. It will be possible through the use of molecular epidemiologic methods. In this inquiry, in order to determine the role of immigrants in the transmission of specific strains to Iran, the studies have been examined which had been conducted based on molecular epidemiologic methods among Iranians and non-Iranians people.

Methods:

All studies from 1997 to the end of March 2017 were examined in three databases of PubMed, Scopus, and Google Scholar and finally, 16 studies were selected.

Results:

The common clustering rate between Iranians and non-Iranians was determined to be 19.8, and the intra-community recent transmission rate was from 0% to 49% with average of 18.1%. The rate of multidrug-resistant tuberculosis (MDR-TB) was 12.5%, which was higher among immigrants, especially Afghans, and a significant number of the strains were Beijing.

Conclusions:

The studies have shown that migrants, especially Afghans, are more effective in transmitting specific strains of tuberculosis to migratory areas. To control tuberculosis, it is necessary to register of immigrant's health information, while enter to the country, so that, by doing appropriate diagnostic tests, the curing the patients, the transmission of tuberculosis to the country would be prevented.

Does the BCG vaccine have different effects on strains of tuberculosis?

Several explanations have been suggested concerning the variety in bacille Calmette-Guerin (BCG) vaccine efficacy on strains of Mycobacterium tuberculosis (Mtb). This study aimed to compare the effect of BCG vaccination history in the prevention of the occurrence of Mtb-Beijing and non-Beijing strains. In this cross-sectional study, 64 patients with pulmonary tuberculosis (TB) were recruited from the Iranian border provinces (North West and West). Isolates were subjected to restriction fragment length polymorphism (RFLP) analysis, using the insertion sequence IS6110 as a probe (IS6110 RFLP) and drug susceptibility testing using the proportion method. Samples were analyzed with Gel Compare II 6.6 and spss version 18. The mean age [standard deviation (SD)] of the patients was 54·4 (SD = 17·0). Overall, 49 cases (76·56%) had no BCG vaccination scar. The prevalence of Beijing strains was 9·38% and drug resistance proportion among the isolates was 14·1% (nine cases). There was a significant relationship between Beijing strains and tuberculosis (TB)-drug resistance in isolates (χ²  = 26·29, P < 0·001). There was also a strong association between vaccination history and Beijing strains (χ²  = 13·23, P = 0·002). Also, a statistical relationship was observed between Beijing strains and drug-resistant TB among patients with a history of vaccination (χ²  = 7·47, P = 0·002). This association was not maintained in the unvaccinated group (P = 0·102). These findings confirm the claim that the vaccine has different effects on different subspecies of tuberculosis. The cause of the high probability of drug resistance in patients with Beijing-TB and vaccination history requires further investigation with a higher sample size.

The relationship between embb306 and embb406 mutations and ethambutol resistant in Mycobacterium tuberculosis isolated from patiens in west of Iran

Background: Mutations in embB gene have been reported in ethambutol (EMB) resistance Mycobacterium tuberculosis (M. tuberculosis) isolates. The aim of this study was survey on embB 306 and 406 EMB resistant M. tuberculosis isolated from patients in West of Iran (2014-2015).

Methods: Fifty strains of M. tuberculosis from patients with pulmonary tuberculosis (TB) were considered. Drug susceptibility using proportional method was performed. Polymerase chain reaction (PCR) -DNA sequencing was applied for mutation in embB 306 and 406 codon detection. Data were analyzed in SPSS 16 software using descriptive statistics and Fisher's exact test (p<0.05).

Results: In this study 7 (14%) M. tuberculosis isolates were resistant to EMB. 6 (85.71%) and 1 (14.28%) resistant isolates had embB 306 and 304 codon mutations, respectively. Between embB306 mutations and resistance to EMB and MDR isolates had a significant relationship (p<0.001).

Conclusion: The data indicated that embB 306 mutations have effect on EMB resistant. Detection of EMB resistant and these mutations prominent for antibiotic prescription

Mycobacterium tuberculosis of the Beijing Genotype in Iran and the World Health Organization Eastern Mediterranean Region: A Meta-Analysis

OBJECTIVE

The Beijing genotype is a distinct genetic lineage of Mycobacterium tuberculosis, which is distributed worldwide, and may cause large outbreaks of multidrug resistance-tuberculosis (MDR-TB). The distribution of such strains in the Eastern Mediterranean region (EMR) is unclear, and clarifying the data is our purpose apart from the presence of Beijing TB in Iran.

METHODS

We searched Published literature from CINAHL Cochrane Library, Current Contents, Database of Abstracts of Reviews of Effects (DARE), ProQuest Google Scholar PubMed, PsycINFO, Thomson Reuters, (SID), and Medical Library (MedLib) to detect relevant studies from the year 2000 to July 2015 with the following keywords: M. tuberculosis, Beijing genotype, EMR, and drug resistance. Random-effect models were used to estimate the proportion of Beijing strains in STATA 14. Heterogeneity was investigated by subgroup analysis and meta-regression.

RESULTS AND CONCLUSION

The meta-prevalence of Beijing strains was 4% (CI 95% = 3-5). The prevalence was different based on types of detection techniques (spoligotyping = 4% vs. other techniques = 6%; p = 0.003) and years of study (before the year 2000 = 2% vs. after year 2000 = 4%, p = 0.004). The Beijing family was most prevalent in Iran and Pakistan. A strong relationship with drug resistance was reported in Pakistan and Iran, and an increasing trend was seen in Pakistan. Additional studies of drug-resistant TB distribution among Beijing strains in EMR countries are needed as well as a time-trend analysis of the Beijing strain infection in the region.