Worldwide Occurrence of Beijing/W Strains ofMycobacterium tuberculosis: A Systematic Review

Abstract

Strains of the Beijing/W genotype family of Mycobacterium tuberculosis have caused large outbreaks of tuberculosis, sometimes involving multidrug resistance. This genetically highly conserved family of M. tuberculosis strains predominates in some geographic areas. We have conducted a systematic review of the published reports on these strains to determine their worldwide distribution, spread, and association with drug resistance. Sixteen studies reported prevalence of Beijing strains defined by spoligotyping; another 10 used other definitions. Beijing strains were most prevalent in Asia but were found worldwide. Associations with drug resistance varied: in New York, Cuba, Estonia, and Vietnam, Beijing strains were strongly associated with drug resistance, but elsewhere the association was weak or absent. Although few reports have measured trends in prevalence, the ubiquity of the Beijing strains and their frequent association with outbreaks and drug resistance underline their importance.

Methodological and Clinical Aspects of the Molecular Epidemiology of Mycobacterium tuberculosis and Other Mycobacteria

“…Findings from recent studies showing an association between phylogenetic lineages and demographic and epidemiological parameters using the SITVIT2 database include (i) the finding of high phylogeographical specificity of M. africanum for Western Africa, with Guinea-Bissau being the epicenter (591); (ii) evidence that the TB epidemic in Sweden a century ago was caused by a closely knit pool of evolutionarily recent strains restricted to Sweden and its immediate neighbors (592); (iii) evidence for a prolonged, clonal, hospital-based outbreak of MDR TB among HIV-positive patients in Peru (593); (iv) determination of the predominance of the Euro-American family among elderly TB patients in Finland just as in Sweden, with the main difference being the presence of significant proportions of isolates of the Ural lineage among Finnish-born cases (also found in Russia, Latvia, and Estonia) but not in Sweden (594); and (v) determination of the association of the Beijing lineage with excessive drug resistance, including MDR and/or XDR TB (286,502,595), and the finding that even though the proportion of drug-resistant strains is significantly higher for Beijing than for non-Beijing strains globally, there are important variations in the distribution of drug resistance (596). Thus, drug resistance was significantly linked to Beijing strains in Russia, Southern Asia, Southeast Asia, and European countries but not to those in the Americas, Western Asia, China, and Japan.…”

Molecular Characterization of Multidrug-Resistant Mycobacterium tuberculosis Isolates from China

“…Moreover, molecular epidemiological studies of TB have illustrated variations in the phylogeography of strains on a global scale (9,10). Beijing family strains are most prevalent globally and are also associated with enhanced acquisition of drug resistance, but their resistance patterns vary regionally (11).…”

Evaluation of Antigen-Specific Immunoglobulin G Responses in Pulmonary Tuberculosis Patients and Contacts

“…About 3.6% of new cases are caused by multidrug-resistant (MDR) strains, and the levels of MDR-TB were found to be higher (ϳ20%) in patients previously treated for TB (3). Notably, a high risk of multidrug resistance and epidemic spread of TB in Asia are associated with the M. tuberculosis Beijing strain (4,5).…”