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Angel Cataldi

Publications and source records attributed to Angel Cataldi.

At least 19 recordsLinked to original sources

Insights into the evolutionary history of tubercle bacilli as disclosed by genetic rearrangements within a PE_PGRS duplicated gene pair.

BACKGROUND: The highly homologous PE_PGRS (Proline-glutamic acid_polymorphic GC-rich repetitive sequence) genes are members of the PE multigene family which is found only in mycobacteria. PE genes are particularly abundant within the genomes of pathogenic mycobacteria where they seem to have expanded as a result of gene duplication events. PE_PGRS genes are characterized by their high GC content and extensive repetitive sequences, making them prone to recombination events and genetic variability. RESULTS: Comparative sequence analysis of Mycobacterium tuberculosis genes PE_PGRS17 (Rv0978c) and PE_PGRS18 (Rv0980c) revealed a striking genetic variation associated with this typical tandem duplicate. In comparison to the M. tuberculosis reference strain H37Rv, the variation (named the 12/40 polymorphism) consists of an in-frame 12-bp insertion invariably accompanied by a set of 40 single nucleotide polymorphisms (SNPs) that occurs either in PE_PGRS17 or in both genes. Sequence analysis of the paralogous genes in a representative set of worldwide distributed tubercle bacilli isolates revealed data which supported previously proposed evolutionary scenarios for the M. tuberculosis complex (MTBC) and confirmed the very ancient origin of "M. canettii" and other smooth tubercle bacilli. Strikingly, the identified polymorphism appears to be coincident with the emergence of the post-bottleneck successful clone from which the MTBC expanded. Furthermore, the findings provide direct and clear evidence for the natural occurrence of gene conversion in mycobacteria, which appears to be restricted to modern M. tuberculosis strains. CONCLUSION: This study provides a new perspective to explore the molecular events that accompanied the evolution, clonal expansion, and recent diversification of tubercle bacilli.

Evolution, Molecular↗

Expression of tuberculosis antigen ESAT-6 in Nicotiana tabacum using a potato virus X-based vector.

A good candidate antigen to create a therapeutic vaccine against TB is the ESAT-6 protein. Antigens produced in plants have already been successfully used as experimental vaccines, and small single-stranded RNA plant viruses have emerged as promising tools to rapidly express large amounts of foreign proteins in susceptible host plants. Here, we present the expression of ESAT-6 protein in Nicotiana tabacum using a vector based on potato virus X (PVX). The complete ESAT-6 open reading frame is expressed as a fusion protein with the 2A peptide of Foot and Mouth Disease Virus and the amino terminal of the PVX coat protein (CP) (PVXESAT-6). This strategy allows the production of free CP and ESAT-6 as well as fused ESAT-2A-CP to obtain recombinant chimaeric virions expressing ESAT-6 at the surface to be used as particulate antigen in vaccination. ESAT-6 expression was tested in agroinfiltrated tobacco leaves and products of the expected molecular masses corresponding to cleaved CP and ESAT-2A-CP fusion protein were observed, with ESAT-6 yields ranging from 0.5% to 1% of total soluble protein. Our study describes for the first time the expression of the ESAT-6 protein in tobacco plants using a PVX-derived vector. This strategy should serve as a convenient, rapid, low-cost expression system and can also be used for the assessment of ESAT-6 production and function prior to stable plant transformation.

Antigens, Bacterial↗

Mycobacterium tuberculosis complex genetic diversity: mining the fourth international spoligotyping database (SpolDB4) for classification, population genetics and epidemiology.

BACKGROUND: The Direct Repeat locus of the Mycobacterium tuberculosis complex (MTC) is a member of the CRISPR (Clustered regularly interspaced short palindromic repeats) sequences family. Spoligotyping is the widely used PCR-based reverse-hybridization blotting technique that assays the genetic diversity of this locus and is useful both for clinical laboratory, molecular epidemiology, evolutionary and population genetics. It is easy, robust, cheap, and produces highly diverse portable numerical results, as the result of the combination of (1) Unique Events Polymorphism (UEP) (2) Insertion-Sequence-mediated genetic recombination. Genetic convergence, although rare, was also previously demonstrated. Three previous international spoligotype databases had partly revealed the global and local geographical structures of MTC bacilli populations, however, there was a need for the release of a new, more representative and extended, international spoligotyping database. RESULTS: The fourth international spoligotyping database, SpolDB4, describes 1939 shared-types (STs) representative of a total of 39,295 strains from 122 countries, which are tentatively classified into 62 clades/lineages using a mixed expert-based and bioinformatical approach. The SpolDB4 update adds 26 new potentially phylogeographically-specific MTC genotype families. It provides a clearer picture of the current MTC genomes diversity as well as on the relationships between the genetic attributes investigated (spoligotypes) and the infra-species classification and evolutionary history of the species. Indeed, an independent Naïve-Bayes mixture-model analysis has validated main of the previous supervised SpolDB3 classification results, confirming the usefulness of both supervised and unsupervised models as an approach to understand MTC population structure. Updated results on the epidemiological status of spoligotypes, as well as genetic prevalence maps on six main lineages are also shown. Our results suggests the existence of fine geographical genetic clines within MTC populations, that could mirror the passed and present Homo sapiens sapiens demographical and mycobacterial co-evolutionary history whose structure could be further reconstructed and modelled, thereby providing a large-scale conceptual framework of the global TB Epidemiologic Network. CONCLUSION: Our results broaden the knowledge of the global phylogeography of the MTC complex. SpolDB4 should be a very useful tool to better define the identity of a given MTC clinical isolate, and to better analyze the links between its current spreading and previous evolutionary history. The building and mining of extended MTC polymorphic genetic databases is in progress.

Computational Biology↗

Identification of an IS6110 insertion site in plcD, the unique phospholipase C gene of Mycobacterium bovis.

The IS6110 repetitive element is present in multiple copies in most Mycobacterium tuberculosis complex bacteria, except for Mycobacterium bovis strains, which usually contain a single copy of IS6110 located on a 1.9 kb PvuII fragment of the direct repeat region. IS6110 transposition can disrupt coding regions and is a major force of genomic variation. In a previous work it was demonstrated that phospholipase C genes are preferential loci for IS6110 transposition in M. tuberculosis clinical strains. Bacterial phospholipase C enzymes participate in pathogenic mechanisms used by different organisms, and have been implicated in intracellular survival, cytolysis and cell-to-cell spread. Four phospholipase C genes (plcA, plcB, plcC and plcD) were detected in the genomes of M. tuberculosis, Mycobacterium africanum, Mycobacterium microti and 'Mycobacterium canettii'. M. bovis and the vaccine strain M. bovis Bacillus Calmette-Guérin contain only the plcD gene. In the present work, the existence of IS6110 insertions within plcD, the unique phospholipase C gene of M. bovis, has been investigated by PCR, Southern blot hybridization and sequencing analysis. In 18 (7.3 %) of 245 isolates analysed, the plcD gene was interrupted by the insertion of one copy of IS6110, which in all cases was transposed in the same orientation and at the same position, 1 972 894, relative to the genome of M. bovis AF2122/97. These 18 isolates were distributed in 6 different spoligotype patterns and contained 4 to 8 IS6110 copies. In contrast, strains showing an intact plcD gene contained one (87 %), two (9.4 %) or three (2.4 %) IS6110 copies, and only a single isolate (1.2 %) had four IS6110 copies. The implications of plcD gene disruption in M. bovis have not been fully investigated, but no differences in the organ distribution of the disease were detected when animals infected with strains from the same spoligotype patterns bearing plcD : : IS6110 and intact plcD were compared.

DNA Fingerprinting↗

Identification of genetic markers for Mycobacterium pinnipedii through genome analysis.

Tuberculosis in seals is caused by Mycobacterium pinnipedii, a member of the Mycobacterium tuberculosis complex. In this study, we evaluated the extent of genetic variability among Mycobacterium bovis and M. pinnipedii by microarray-based comparative genomics. We identified two deletions that are exclusive to M. pinnipedii: PiD1 that removes the orthologues of the M. tuberculosis genes Rv3530c and Rv3531c, and PiD2 that encompasses genes Rv1977 and Rv1978. Interestingly, a deletion overlapping the previously described RD2 region was identified in some isolates of Mycobacterium microti and further characterised.

Fur Seals↗

Mutation in mce operons attenuates Mycobacterium tuberculosis virulence.

On the Mycobacterium tuberculosis genome there are four mce operons, all of which are similar in sequence and organization, and code for putatively exported proteins. To investigate whether Mce proteins are essential for virulence, we generated knock-out mutants in mce1, mce2 and mce3 operons of M. tuberculosis and evaluated their ability to multiply in a mammalian host. The allelic replacement was confirmed in each mutant strain by Southern blotting. RT-PCR experiments demonstrated the lack of in vitro expression of mutated genes in Deltamce1 and Deltamce2 mutants. On the other hand, no expression of mce3 was detected in either the wild-type or mutant strains. Similar doubling time and growth characteristics in in vitro culture were observed for mutants and parental strains. The intratracheal route was used to infect BALB/c mice with the Deltamce3, Deltamce2 and Deltamce1 mutants. Ten weeks after infection, all mice infected with the Deltamce mutants survived, while those infected with the wild-type strain died. This long survival correlated with very low counts of colony-forming units (CFU) in the lungs. Deltamce1-infected mice developed very few and small granulomas, while animals infected with Deltamce3 or Deltamce2 mutants showed delayed granuloma formation. Mice infected with Deltamce1 did not develop pneumonia, while animals infected with Deltamce3 and Deltamce2 mutants showed small pneumonic patches. In spleens, bacterial counts of mutant strains were less reduced than in lungs, compared with those of wild-type. In contrast, no such attenuation was observed when the intraperitoneal route was used for infection. Moreover, Deltamce1 mutants appear to be more virulent in lungs after intraperitoneal inoculation. In conclusion, mce operons seem to affect the virulence of M. tuberculosis in mice, depending on the route of infection. Hypotheses are discussed to explain this last issue. Thus, mutants in these genes seem to be good candidates for vaccine testing.

Animals↗

Discriminatory power and reproducibility of novel DNA typing methods for Mycobacterium tuberculosis complex strains.

In recent years various novel DNA typing methods have been developed which are faster and easier to perform than the current internationally standardized IS6110 restriction fragment length polymorphism typing method. However, there has been no overview of the utility of these novel typing methods, and it is largely unknown how they compare to previously published methods. In this study, the discriminative power and reproducibility of nine recently described PCR-based typing methods for Mycobacterium tuberculosis were investigated using the strain collection of the interlaboratory study of Kremer et al. This strain collection contains 90 M. tuberculosis complex and 10 non-M. tuberculosis complex mycobacterial strains, as well as 31 duplicated DNA samples to assess reproducibility. The highest reproducibility was found with variable numbers of tandem repeat typing using mycobacterial interspersed repetitive units (MIRU VNTR) and fast ligation-mediated PCR (FLiP), followed by second-generation spoligotyping, ligation-mediated PCR (LM-PCR), VNTR typing using five repeat loci identified at the Queens University of Belfast (QUB VNTR), and the Amadio speciation PCR. Poor reproducibility was associated with fluorescent amplified fragment length polymorphism typing, which was performed in three different laboratories. The methods were ordered from highest discrimination to lowest by the Hunter-Gaston discriminative index as follows: QUB VNTR typing, MIRU VNTR typing, FLiP, LM-PCR, and spoligotyping. We conclude that both VNTR typing methods and FLiP typing are rapid, highly reliable, and discriminative epidemiological typing methods for M. tuberculosis and that VNTR typing is the epidemiological typing method of choice for the near future.

Bacterial Typing Techniques↗

Spoligotype analysis of Mycobacterium bovis isolates from Northern México.

Bovine tuberculosis is still rife in Latin America, producing huge economic losses. There are very few studies of the way this disease is spread through this geographical region, particularly in countries that border those that are almost free of Mycobacterium bovis. In this work, we have analyzed the spacer oligonucleotide typing (spoligotype) patterns of M. bovis isolates from cattle at Ciudad Juárez, a Mexican city close to El Paso, Texas. Fifty-eight M. bovis isolates collected from a herd in Northern Mexico were studied by spoligotyping. Nine spoligotype patterns were observed in total. Two were predominant (SB0121 and SB0140) and accounted for 50% and 14% of the isolates, respectively. Six patterns were found to be already described in an international M. bovis spoligotype database, while the other three (SB0985, SB0986, and SB0987) were novel. Interestingly, none of the isolates corresponded to any other Mexican pattern previously reported. This is the first spoligotype analysis of M. bovis strains from a border city between Mexico and the United States. The necessity for further studies to formulate a better identification of M. bovis strains within, and its dissemination between, the two countries is discussed.

Animals↗

Use of touch-down polymerase chain reaction to enhance the sensitivity of Mycobacterium bovis detection.

The confirmatory diagnosis of Mycobacterium bovis (M. bovis) in animal samples is carried out by culture in Stonebrink media. However, culture is very slow because of the extremely long duplication time of the bacillus and difficult because of the scarcity of bacilli in diagnostic samples. This study describes the development of a single-tube touch-down polymerase chain reaction (PCR) protocol for the detection of M. bovis using primers that target the IS6110 element. Spiked water and milk as well as routine diagnostic samples (milk and nasal swabs) from M. bovis-positive cattle were tested. This protocol allows the rapid and sensitive detection of M. bovis in bovine samples by enhancing the sensitivity of standard PCR amplification.

Animals↗

Multicenter evaluation of mycobacteria identification by PCR restriction enzyme analysis in laboratories from Latin America and the Caribbean.

The identification of mycobacterial species in clinical isolates is essential for making patient care decisions. Polymerase chain reaction (PCR) restriction enzyme analysis (PRA) is a simple and rapid identification method, based on amplification of 441 bp of the hsp65 gene and restriction with BstEII and HaeIII. As a contribution to the validation of PRA, a multicenter study was performed in eight laboratories located in Argentina, Brazil, Colombia, Chile, and Guadeloupe. Each laboratory received 18 coded isolates from the collection of the Institute of Tropical Medicine (Antwerp, Belgium), representing duplicates of nine laboratory strains: Mycobacterium terrae CIPT 140320001, Mycobacterium scrofulaceum CIPT 140220031, Mycobacterium flavescens ATCC 14474, Mycobacterium triviale ATCC 23292, Mycobacterium nonchromogenicum ATCC 19530, Mycobacterium chitae ATCC 19627, Mycobacterium abscessus ATCC 19977, Mycobacterium kansasii ATCC 12478, and Mycobacterium peregrinum ATCC 14467. A detailed protocol including amplification, enzymatic digestion, and gel preparation was provided to each laboratory. Two laboratories identified correctly all 18 (100%) isolates, one identified correctly 17 (94.5%), two identified 14 (77.7%), one identified 11 (61%), and two identified 8 (44.4%) isolates. Errors detected in laboratories with more than 77% accuracy were associated with electrophoresis running conditions and an unspecific amplicon produced by a single strain. Lower accuracy was mainly related to inappropriate use of DNA markers and insufficient training in interpretation of patterns. In conclusion, the PRA method was readily implemented in some Latin American and Caribbean laboratories of mycobacteria, but improvements in critical points, as gel running conditions and training in interpretiation of patterns, are needed in order to improve accuracy. In others, improvement in critical points is still necessary.

Bacterial Proteins↗

Shiga toxin-producing Escherichia coli in healthy young beef steers from Argentina: prevalence and virulence properties.

Between July 1999 and December 2000, the prevalence of Shiga toxin-producing Escherichia coli (STEC) was established in 200 Argentine healthy young beef steers (14-16 months old) grown under local production systems with a feed grain period of 3-4 months, and the STEC strains isolated were examined in regard to their phenotypic and genotypic characteristics. Stool samples (n = 70) and rectal swabs (n = 130) were taken at the slaughterhouse level. By polymerase chain reaction (PCR), Shiga toxin (stx) gene sequences were detected in 69% of the samples. Eighty-six STEC strains were isolated from 39% of the animals. Serogroups identified, in order of frequency, were: O8 (16 strains), O113 (14), O103 (5), O91 (4), O171 (3), O174 (3), O25 (2), O112 (2), O145 (2), O2, O11, O104, O121, O128, O143, O146, O157. The most frequent serotype isolated was O8:H19 (12.9%). A total of 17 serotypes, including E. coli O157:H7 found in one animal (0.5%), have been previously associated with hemolytic uremic syndrome (HUS), bloody and non-bloody diarrhea in different countries, including Argentina. The prevalent genotype isolated was stx2 (51 of 86, 59.3%). Subtyping of stx2 variants showed the prevalence of stx2vh-b (25.6%) and stx2vh-a types (24.4%), and revealed the presence of an atypical stx2-v. Only 7.0% of STEC strains carried eae, and 33.7% harbored EHEC-hlyA gene. The full virulent genotype (stx/eae/EHEC-hlyA) was found to be present in 4 of the 86 (4.7%) STEC strains isolated. This research indicates that young steers from the main beef-producing area of Argentina are an important reservoir of STEC strains; however, its importance as agents of human diseases in our country has still to be established.

Abattoirs↗

The knockout of the lprG-Rv1410 operon produces strong attenuation of Mycobacterium tuberculosis.

P27 lipoprotein was previously described as an antigen in the Mycobacterium tuberculosis complex, encoded by the lprG gene, also named Rv1411 in the TubercuList (http://genolist.pasteur.fr/TubercuList) gene bank. It forms an operon with Rv1410 that encodes for an efflux pump, P55. A mutant of the H37Rv strain of M. tuberculosis not producing P27 (strain DeltaP27) was obtained by two-step mutagenesis using the counterselectable marker sacB and a thermosensitive origin of replication in the shuttle plasmid pPR27. By RT-PCR, we observed no lprG or Rv1410 mRNA in the DeltaP27 mutant strain compared with the wild type and complemented strains. Western blot experiments using anti-P27 polyclonal sera showed that the P27 protein was present both in the parental and in a complemented strain, in which the entire lprG-Rv1410 operon was reintroduced, but absent in the mutant strain. The three strains showed similar growth kinetics and characteristics in culture broth. To study the effect of the lprG mutation on M. tuberculosis virulence, BALB/c mice were inoculated to determine bacterial loads in spleens. At days 15 and 35 after infection, decreases of 1.5 and 2.5 logs in the bacterial load were found, respectively, in animals inoculated with the DeltaP27 mutant strain or with the wild type. This attenuation was reverted in the complemented strain. These results demonstrated that lprG gene is required for growth of M. tuberculosis in immunocompetent mice. The reversion of attenuation in the complemented strain indicates that the attenuated phenotype resulted from disruption of the lprG-Rv1410 operon.

Animals↗

Microarray analysis of Mycobacterium microti reveals deletion of genes encoding PE-PPE proteins and ESAT-6 family antigens.

Mycobacterium microti is the agent of tuberculosis in wild voles and has been used as a live vaccine against tuberculosis in man and cattle. To explore the M. microti genome in greater detail, we used a M. tuberculosis H37Rv genomic DNA microarray to detect gene deletions among M. microti isolates. A number of deletions were identified that correlated with those described previously (Infect. Immun. 70 (2002) 5568) but a novel M. microti deletion was also found (MiD4) which removes 5 genes that code for ESAT-6 family antigens and PE-PPE proteins. Southern blot experiments showed that this region was also deleted from M. pinnipedii, a mycobacterium isolated from seals that is closely related to M. microti. Genes encoding ESAT-6 antigens and PE-PPE proteins appear to be frequently deleted from M. microti, and the implications of this are discussed.

Antigens, Bacterial↗

Genome sequence based, comparative analysis of the fluorescent amplified fragment length polymorphisms (FAFLP) of tubercle bacilli from seals provides molecular evidence for a new species within the Mycobacterium tuberculosis complex.

Tuberculosis in seals is caused by a member of the Mycobacterium tuberculosis complex referred to as the 'seal bacillus'. Fluorescent amplified-fragment length polymorphism (FAFLP) analysis was applied to isolates from four Australian and six Argentinean seals and compared with FAFLP pattern for standard strains belonging to the M. tuberculosis complex. The FAFLP profiles derived from EcoRI/MseI restricted fragments of blind coded DNA samples differentiated the seal bacillus from other members of the M. tuberculosis complex. According to the phylogenetic analysis performed using FAFLP data, seal bacilli appear to have diverged significantly from other members of the M. tuberculosis complex. We describe the suitability of a panel of 19 highly polymorphic markers for rapid identification and comparative genomic analyses of the seal bacillus strains. It is likely that these bacilli got separated from the M. tuberculosis lineage as a result of different insertion deletion events occurring on a genome wide scale. Our analysis reveals that the seal bacillus and M. bovis are genetically related and therefore, might have originated from a common ancestor. Our data additionally support the hypothesis that seal bacillus occupies a unique taxonomic position within the M. tuberculosis complex.

Animals↗

Tuberculosis in seals caused by a novel member of the Mycobacterium tuberculosis complex: Mycobacterium pinnipedii sp. nov.

A comparison of Mycobacterium tuberculosis complex isolates from seals (pinnipeds) in Australia, Argentina, Uruguay, Great Britain and New Zealand was undertaken to determine their relationships to each other and their taxonomic position within the complex. Isolates from 30 cases of tuberculosis in six species of pinniped and seven related isolates were compared to representative and standard strains of the M. tuberculosis complex. The seal isolates could be distinguished from other members of the M. tuberculosis complex, including the recently defined 'Mycobacterium canettii' and 'Mycobacterium caprae', on the basis of host preference and phenotypic and genetic tests. Pinnipeds appear to be the natural host for this 'seal bacillus', although the organism is also pathogenic in guinea pigs, rabbits, humans, Brazilian tapir (Tapirus terrestris) and, possibly, cattle. Infection caused by the seal bacillus is predominantly associated with granulomatous lesions in the peripheral lymph nodes, lungs, pleura, spleen and peritoneum. Cases of disseminated disease have been found. As with other members of the M. tuberculosis complex, aerosols are the most likely route of transmission. The name Mycobacterium pinnipedii sp. nov. is proposed for this novel member of the M. tuberculosis complex (the type strain is 6482(T)=ATCC BAA-688(T)=NCTC 13288(T)).

Animals↗

The Mycobacterium tuberculosis recombinant 27-kilodalton lipoprotein induces a strong Th1-type immune response deleterious to protection.

Th1 immune response is essential in the protection against mycobacterial intracellular pathogens. Lipoproteins trigger both humoral and cellular immune responses and may be candidate protective antigens. We studied in BALB/c mice the immunogenicity and the protection offered by the recombinant 27-kDa Mycobacterium tuberculosis lipoprotein and the corresponding DNA vaccine. Immunization with the 27-kDa antigen resulted in high titers of immunoglobulin G1 (IgG1) and IgG2a with a typical Th1 profile and a strong delayed hypersensitivity response. A strong proliferation response was observed in splenocytes, and significant nitric oxide production and gamma interferon secretion but not interleukin 10 secretion were measured. Based on these criteria, the 27-kDa antigen induced a typical Th1-type immune response thought to be necessary for protection. Surprisingly, in 27-kDa-vaccinated mice (protein or DNA vaccines) challenged by M. tuberculosis H37Rv or BCG strains, there was a significant increase in the numbers of CFU in the spleen compared to that for control groups. Furthermore, the protection provided by BCG or other mycobacterial antigens was completely abolished once the 27-kDa antigen was added to the vaccine preparations. This study indicates that the 27-kDa antigen has an adverse effect on the protection afforded by recognized vaccines. We are currently studying how the 27-kDa antigen modulates the mouse immune response.

Animals↗

Snapshot of moving and expanding clones of Mycobacterium tuberculosis and their global distribution assessed by spoligotyping in an international study.

The present update on the global distribution of Mycobacterium tuberculosis complex spoligotypes provides both the octal and binary descriptions of the spoligotypes for M. tuberculosis complex, including Mycobacterium bovis, from >90 countries (13,008 patterns grouped into 813 shared types containing 11,708 isolates and 1,300 orphan patterns). A number of potential indices were developed to summarize the information on the biogeographical specificity of a given shared type, as well as its geographical spreading (matching code and spreading index, respectively). To facilitate the analysis of hundreds of spoligotypes each made up of a binary succession of 43 bits of information, a number of major and minor visual rules were also defined. A total of six major rules (A to F) with the precise description of the extra missing spacers (minor rules) were used to define 36 major clades (or families) of M. tuberculosis. Some major clades identified were the East African-Indian (EAI) clade, the Beijing clade, the Haarlem clade, the Latin American and Mediterranean (LAM) clade, the Central Asian (CAS) clade, a European clade of IS6110 low banders (X; highly prevalent in the United States and United Kingdom), and a widespread yet poorly defined clade (T). When the visual rules defined above were used for an automated labeling of the 813 shared types to define nine superfamilies of strains (Mycobacterium africanum, Beijing, M. bovis, EAI, CAS, T, Haarlem, X, and LAM), 96.9% of the shared types received a label, showing the potential for automated labeling of M. tuberculosis families in well-defined phylogeographical families. Intercontinental matches of shared types among eight continents and subcontinents (Africa, North America, Central America, South America, Europe, the Middle East and Central Asia, and the Far East) are analyzed and discussed.

Bacterial Typing Techniques↗