Expanded Geographical Distribution of the N Family of Mycobacterium tuberculosis Strains within the United States

Abstract

The N and W-Beijing families of Mycobacterium tuberculosis are phylogenetically closely related. The ability of the W-Beijing family to rapidly cause widespread disease is well described; however, few outbreaks involving the N family have been reported outside the New York City, N.Y., area. During 2002 to 2003, Seattle, Wash., experienced a rapidly expanding tuberculosis outbreak involving 38 persons in a 23-month period. The outbreak strain, SBRI9, exhibited the genotypic properties of the N family. Its IS6110 restriction fragment length polymorphism pattern was identical or nearly identical to those of two N family strains that were responsible for clusters of tuberculosis cases, including a large nosocomial outbreak, in New York City and New Jersey from 1989 to 1990. It was also identical to strains involved in late 1990s tuberculosis cases in Michigan, Maryland, and Arkansas. Further monitoring of the N family may show that it shares with the W-Beijing family the propensity to spread rapidly, suggesting that this characteristic evolved prior to the divergence of the two genetic lineages

Evaluation of a High-Throughput Repetitive-Sequence-Based PCR System for DNA Fingerprinting of Mycobacterium tuberculosis and Mycobacterium avium Complex Strains

“…The 11 epidemiologically linked Seattle outbreak isolates were known to belong to spoligogroup 1. They shared an identical 15-band IS6110 banding pattern designated SBRI9, along with additional common genotypic markers that placed them in the N subfamily of the W-Beijing clade (18). Ten of these isolates exhibited Ն98% similarity to each other by rep-PCR.…”

“…However, in some RFLP experiments, strain 181 exhibited faint additional bands approximately 1.5 and 2.25 kb in size which were not visible in the other strains (not shown). Although the 11 SBRI9 isolates were correctly grouped with each other by rep-PCR analysis, strain 181 might have been considered unlinked to the others by rep-PCR were it not for the availability of independent genotypic and epidemiological information (18). Based on the similarity observed among these 11 SBRI9 isolates, 93% similarity was chosen as the cutoff value for clustered M. tuberculosis isolates.…”

“…In order to protect donor privacy, isolates were submitted by Seattle area clinical laboratories without patient identifiers, according to human subjects protection protocols approved by the Seattle Biomedical Research Institute and University of Washington Institutional Review Boards. The study also included 11 epidemiologically linked clinical isolates archived from a recent tuberculosis outbreak among U.S.-born and foreign-born homeless people in Seattle (18). These 11 isolates were known to share common spoligotypes and IS6110-RFLP banding patterns.…”

“…Genotypic analysis of M. tuberculosis isolates has been used to confirm tuberculosis outbreaks, to investigate tuberculosis transmission and reactivation in communities, to confirm cross-contamination in the laboratory, and to study clonal expansion of strains (3,5,12,13,15,18,23). Genotypic analysis of atypical mycobacteria, most notably the M. avium complex (MAC), has been similarly useful for investigating routes of acquisition from environmental sources, confirming contamination of laboratory cultures, and studying clonal expansion (2,11,29).…”

Tuberculose Multirresistente por Estirpes da Família Beijing, em Doentes de Lisboa, Portugal: Estudo Preliminar

“…Embora já tenha estado envolvida (como a estirpe N) em epidemias de tuberculose sensível e em clusters não associados à resistência verifica-se que, em muitas regiões (Estónia, Alemanha, África do Sul, Cuba), aparece associada à resistência aos antituberculosos e, geralmente, induzindo formas mais graves de TB, maior falência terapêutica e maior número de recaídas, do que outras famí-lias, continuando por entender, se tem maior facilidade em adquirir multirresistência ou se tem maior tendência para a transmissão. 12,[26][27][28][29][30][31][32][33][34] De igual modo, por caracterizar está a virulência desta família, definida pela capacidade em causar morbilidade e mortalidade excessivas.…”