Analysis of the population structure of Mycobacterium tuberculosis strains from the People's Republic of China showed that the vast majority belong to a genetically closely related group. These strains shared the majority of their IS6110 DNA-containing restriction fragments, and also, the DNA polymorphism associated with other repetitive DNA elements, like the polymorphic GC-rich sequence and the direct repeat, was very limited. Because the majority of these strains originated from the province of Beijing, we designated this grouping the ''Beijing family'' of M. tuberculosis strains. Strains of this family were also found to dominate in neighboring countries such as Mongolia, South Korea, and Thailand, whereas a low prevalence of such strains was observed in countries on other continents. These data indicate that strains of the Beijing family recently expanded from a single ancestor which had a selective advantage. It is speculated that long-term Mycobacterium bovis BCG vaccination may be one of the selective forces implicated in the successful spread of the Beijing genotype.

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The 81-bp region of the rpoB gene in 66 Rif r Mycobacterium tuberculosis isolates from China, Japan, Korea, and Taiwan was analyzed. Twelve single-nucleotide substitutions in the rpoB gene were detected. The most prevalent mutations were at Ser-531 (52%), Asp-516 (17%), and His-526 (11%). Mutations were not found in seven (11%) of the isolates. Higher mutation rates in 50 Beijing family isolates were found than in other isolates for mutations at Asp-516 (18 and 12.5%, respectively) and His-526 (12 and 6.3%, respectively). The different rates of mutation may reflect the choice of rifamycin analogs.

Forty-eight Mycobacterium tuberculosis strains were obtained from patients living in metropolitan Manila, Republic of the Philippines. Three molecular typing methods, IS6110 restriction fragment length polymorphism, spoligotyping, and DNA sequencing of the oxyR, gyrA, and katG loci, established that these strains have restricted diversity and are members of a related genetic group of organisms. Comparison of the DNA fingerprint patterns with those in international databases confirmed the uniqueness of this group of isolates, which we designate the Manila family of M. tuberculosis.The advent of IS6110-based restriction fragment length polymorphism (RFLP) typing of Mycobacterium tuberculosis has led to fingerprinting studies throughout the world (13, 16). These studies have provided insight on the transmission of tuberculosis within and among different geographical areas of the world (10, 16). One finding of IS6110 DNA fingerprinting is that the population structure of M. tuberculosis differs in regions in that some geographical areas are associated with families or groups of related isolates, such as the Beijing, Haarlem, and African genotype families (2,5,7,8,15 Microbiol. 1995Microbiol. , abstr. U-4, p. 117, 1995. Additional DNA typing technologies, such as spoligotyping (6), analysis of the pseudogene oxyR (12), polymorphic GC-rich sequence RFLP (9), and typing of variable numbers of tandem repeats (1) confirmed these family groupings of M. tuberculosis.Since we noticed that tuberculosis isolates from Filipinos, which account for 50% of the M. tuberculosis isolates from foreign-borne patients in Hawaii (State of Hawaii Department of Health data, www.hawaiistate/health/tuberculosis, 2001), had related spoligotyping patterns, we decided to directly investigate isolates from Manila, Republic of the Phillipines (J. T. Douglas, L. Qian, J. C. Montoya, S. Sreevatsan, J. M. Musser, and J. D. A. van Embden, Abstr. 97th Gen. Meet. Am. Soc. Microbiol., abstr. U-166, p. 572, 1997). Manila is the largest city in the Philippines (about 10 million people); it has a high population density and socioeconomic problems, and tuberculosis is highly endemic. Manila is also geographically isolated within an island nation, which could be a fertile ground for clonal expansion of M. tuberculosis. Because little is known about the population structure of tuberculosis in the Philippines, we subjected a random sample of M. tuberculosis isolates originating in Manila to various molecular typing techniques to search for genetic markers that might be useful in studying M. tuberculosis isolates recovered from immigrant populations within Hawaii.The Tuberculosis Study Group at the Research Institute for Tropical Medicine and the Philippine General Hospital provided 48 M. tuberculosis isolates from separate individuals in the metropolitan Manila area. Initially 18 isolates were collected in December 1995, followed by 30 isolates 8 months later. Of these, 35 came with some demographic data. These isolates were from 18 males and 17 females. Th...

Direct repeat spoligotyping of 85 paraffin-embedded lung biopsies was used to investigated the occurrence around Beijing of the Beijing family of Mycobacterium tuberculosis. Samples ranged in time from 1956 to 1990. Hybridization patterns were found with 49 (58%) samples, and 45 (92%) produced typical Beijing family patterns extending over the 34-year period.

Background To develop and evaluate rapid, molecular-based drug susceptibility tests (DST) for extensively drug resistant tuberculosis (XDR-TB), we assembled a phenotypically and genotypically diverse collection of M. tuberculosis (Mtb) isolates from patients evaluated for drug resistance in four high-burden countries. Methods Mtb isolates from India (n=111), Moldova (n=90), the Philippines (n=96), and South Africa (n=103) were selected from existing regional and national repositories to maximize phenotypic diversity for resistance to isoniazid, rifampin, moxifloxacin, ofloxacin, amikacin, kanamycin and capreomycin. MGIT-960 was performed on viable isolates in one laboratory using standardized procedures and drug concentrations. Genetic diversity within drug-resistance phenotypes was assessed. Results Nineteen distinct phenotypes were observed among 400 isolates with complete DST results. Diversity was greatest in the Philippines (14 phenotypes) and least in South Africa (9 phenotypes). Nearly all phenotypes included multiple genotypes. All sites provided isolates resistant to injectable but susceptible to fluoroquinolone drugs. Many patients were taking antibiotics to which their current infection was resistant. Discussion Diverse phenotypes for XDR-TB-defining drugs, including resistance to fluoroquinolone and/or injectable drugs in rifampin-sensitive isolates indicate that rifampin-sensitivity does not ensure effectiveness of a standard four-drug regimen. Thus, rapid, low-cost DST assays for first- and second-line drugs are needed.

Alternative diagnostic methods, such as sequence-based techniques, are necessary for increasing the proportion of tuberculosis cases tested for drug resistance. Despite the abundance of data on drug resistance, isolates can display phenotypic resistance but lack any distinguishable markers. Furthermore, because resistance-conferring mutations develop under antibiotic pressure, different drug regimens could favor unique single-nucleotide polymorphisms (SNPs) in different geographical regions. A total of 407 isolates were collected from four geographical regions with a high prevalence of drug-resistant tuberculosis (India, Moldova, the Philippines, and South Africa). The "hot spot" or promoter sequences of nine genes (rpoB, gyrA, gyrB, katG, inhA promoter, ahpC promoter, eis promoter, rrs, and tlyA) associated with resistance to four types of antibiotics (rifampin, isoniazid, fluoroquinolones, and aminoglycosides) were analyzed for markers. Four genes contributed largely to resistance (rpoB, gyrA, rrs, and katG), two genes contributed moderately to resistance (the eis and inhA promoters), and three genes contributed little or no resistance (gyrB, tlyA, and the ahpC promoter) in clinical isolates. Several geographical differences were found, including a double mutation in rpoB found in 37.1% of isolates from South Africa, the C¡T mutation at position ؊12 of the eis promoter found exclusively in 60.6% of isolates from Moldova, and the G¡A mutation at position ؊46 of the ahpC promoter found only in India. These differences in polymorphism frequencies emphasize the uniqueness of isolates found in different geographical regions. The inclusion of several genes provided a moderate increase in sensitivity, and elimination of the examination of other genes might increase efficiency.

With its airborne transmission and prolonged latency period, Mycobacterium tuberculosis spreads worldwide as one of the most successful bacterial pathogens and continues to kill millions of people every year. M. tuberculosis lineage 1 is inferred to originate ancestrally based on the presence of the 52-bp TbD1 sequence and analysis of single nucleotide polymorphisms. Previously, we briefly reported the complete genome sequencing of M. tuberculosis strains 96121 and 96075, which belong to the ancient Manila family and modern Beijing family respectively. Here we present the comprehensive genomic analyses of the Manila family in lineage 1 compared to complete genomes in lineages 2–4. Principal component analysis of the presence and absence of CRISPR spacers suggests that Manila isolate 96121 is distinctly distant from lineages 2–4. We further identify a truncated whiB5 gene and a putative operon consisting of genes encoding a putative serine/threonine kinase PknH and a putative ABC transporter, which are only found in the genomes of Manila family isolates. Six single nucleotide polymorphisms are uniquely conserved in 38 Manila strains. Moreover, when compared to M. tuberculosis H37Rv, 59 proteins are under positive selection in Manila family isolate 96121 but not in Beijing family isolate 96075. The unique features further serve as biomarkers for Manila strains and may shed light on the limited transmission of this ancestral lineage outside of its Filipino host population.