Diversity Of Mycobacterium Tuberculosis Strains Research Articles

Genetic Diversity of Mycobacterium tuberculosis Strains Isolated from HIV-Infected Patients in Mexico.

There has been very limited investigation regarding the genetic diversity of Mycobacterium tuberculosis (MTb) strains isolated from human immunodeficiency virus (HIV)-infected patients in Mexico. In this study, we isolated 93 MTb strains from pulmonary and extrapulmonary samples of HIV-infected patients treated in a public hospital in Mexico City to evaluate the genetic diversity using spoligotyping and mycobacterial interspersed repetitive unit-variable-number tandem-repeat (MIRU-VNTR) typing (based on 24 loci). The cohort comprised 80 male and 13 female individuals. There was a positive correlation between a high HIV viral load (>100,000 copies) and extrapulmonary tuberculosis (TB) (r = 0.306, p = 0.008). Lineage 4 was the most frequent lineage (79 strains). In this lineage, we found the H clade (n = 24), including the Haarlem, H3, and H1 families; the T clade (n = 22), including T1 and T2; the X clade (n = 15), including X1 and X3; the LAM clade (n = 14), including LAM1, LAM2, LAM3, LAM6, and LAM9; the S clade (n = 2); Uganda (n = 1); and Ghana (n = 1). We also found 12 strains in the EAI clade belonging to lineage 1, including the EAI2-Manila and EAI5 families. Interestingly, we identified one strain belonging to the Beijing family, which is part of lineage 2. One strain could not be identified. This study reports high genetic diversity among MTb strains, highlighting the need for a molecular epidemiological surveillance system that can help to monitor the spread of these strains, leading to more appropriate measures for TB control in HIV-infected patients.

Genetic diversity of Mycobacterium tuberculosis strains isolated from spiritual holy water site attendees in Northwest Ethiopia. A cross-sectional study

BackgroundThe genetic diversity of Mycobacterium tuberculosis complex (MTBC) strains was characterized among isolates from individuals with pulmonary tuberculosis (PTB) symptoms attended holy water sites (HWSs) in the Amhara region, Ethiopia. MethodsA cross-sectional study was done from June 2019 to March 2020 to describe the genetic diversity and drug-resistance profiles of MTBC isolates. Sputum specimens were collected and cultured in the Löwenstein-Jensen culture medium. Line Probe Assay, MTBDRplus VER 2.0, and MTBDRsl VER 2.0 were used to detect first-and second-line anti-TB drug-resistance patterns. A spoligotyping technique was utilized to characterize the genetic diversity. Statistical analysis was performed using STATA 15. ResultsOf 560 PTB-symptomatic participants, 122 (21.8%) were culture-positive cases. Spoligotyping of 116 isolates revealed diverse MTBC sublineages, with four major lineages: Euro-American (EA) (Lineage 4), East-African-Indian (EAI) (Lineage 3), Ethiopian (ETH) (Lineage 7), East Asian (EA) (Lineage 2). The majority (96.6%) of the isolates were EA (lineage 4) and EAI, with proportions of 54.3% and 42.2%, respectively. A total of 31 spoligotype patterns were identified, 26 of which were documented in the SITVIT2 database. Of these, there were 15 unique spoligotypes, while eleven were grouped with 2-17 isolates. SIT149/T3-ETH (n = 17), SIT26/CAS1-DELHI (n = 16), SIT25/CAS1-DELHI (n = 12), and SIT52/T2 (n = 11) spoligotypes were predominant. A rare spoligotype pattern: SIT41/Turkey and SIT1/Beijing, has also been identified in North Shewa. The overall clustering rate of sub-lineages with known SIT was 76.4%.Of the 122 culture-positive isolates tested, 16.4% were resistant to rifampicin (RIF) and/or isoniazid (INH). Multidrug-resistant TB (MDR-TB) was detected in 12.3% of isolates, five of which were fluoroquinolones (FLQs) resistant. SIT149/T3-ETH and SIT21/CAS1-KILI sublineages showed a higher proportion of drug resistance. ConclusionsDiverse MTBC spoligotypes were identified, with the T and CAS families and EA (lineage 4) predominating. A high prevalence of drug-resistant TB, with SIT149/T3-ETH and CAS1-KILI sublineages comprising a greater share, was observed. A study with large sample size and a sequencing method with stronger discriminatory power is warranted to understand better the genetic diversity of circulating MTBC in this cohort of study, which would help to adopt targeted interventions.

Assessing the Genetic Diversity of Mycobacterium tuberculosis Strains in Kerala, India: A Comprehensive Study

Assessing the Genetic Diversity of Mycobacterium tuberculosis Strains in Kerala, India: A Comprehensive Study

799. Genetic Diversity of Mycobacterium tuberculosis Strains Causing Drug-Resistant Tuberculosis in Central Region of Mozambique: The Whole-Genome Sequencing

BackgroundKnowing the genetic diversity of M. tuberculosis strains causing drug-resistant tuberculosis (DR-TB) in high burden TB and low resources countries such as Mozambique is a key factor to TB disease spread control and world TB epidemic control. Whole-genome sequencing (WGS) better describes molecular diversity, lineages and sub lineages, relationship between strains, underline mutations conferring drug-resistant TB, which may not be shown by molecular and phenotypic tests. As far as we know this is the first study that describes genetic diversity of M. tuberculosis strains causing DR-TB and using WGS in central region of Mozambique.We aim to describe genetic diversity of M. tuberculosis strains causing DR-TB in central Mozambique.MethodsA total of 35 strains from Beira Mozambique were evaluated with genotypic tests (Genotype MTBDRplus™, and MTBDRsl™); phenotypic (MGIT-SIRE™) and DST. All isolates resistant to isoniazid (H) or rifampicin (R) or both were submitted to WGS Illumina HiSeq 2000 and analyzed with TB profiler database and phylogenetic tree was done using Figtree tool. This was a descriptive cross-sectional study.ResultsWGS shown that strains analyzed, belongs to three of six major lineages, with Lineage 4: 25(71.4%); Lineage 1: 5(14.3%); and Lineage 2 Beijing family: 5(14.3%)]. All pre-XDR strains 3(8.6%) were from lineage 4.3. By WGS, all 35 strains had any mutations conferring DR-TB while in one strain, mutation was not shown by genotypic neither phenotypic DST. Compared with genotypic tests, WGS had best performance in showing mutation conferring resistance to etambutol 12/35 (34.3%) and 7/35 (20%).ConclusionThe DR-TB disease in Beira Mozambique is mainly caused by M. tuberculosis strains of Lineage 4, sub-lineage 3 although lineage 1 and 2 are also present. WGS shows underline mutations causing DR–TB that are not detected by genotypic and phenotypic DST test.Disclosures All authors: No reported disclosures.

Genetic diversity and distribution of Mycobacterium tuberculosis genotypes in Limpopo, South Africa

BackgroundTuberculosis remains a major health problem and knowledge of the diversity of Mycobacterium tuberculosis strains in specific geographical regions can contribute to the control of the disease. This study describes the genetic profile of M. tuberculosis in five districts of Limpopo Province.MethodsA total 487 isolates were collected from the National Health Laboratory Services from all regions/districts of Limpopo Province. Only 215 isolates were confirmed to be M. tuberculosis by Bactec Mycobacterium Growth Indicator Tube 960® and Rhodamine-Auramine staining. Isolates were subcultured on Löwenstein-Jensen medium agar slants to validate purity. They were spoligotyped and data analysed using the international spoligotyping database 4 (SpolDB4).ResultsOf the 215 isolates, 134 (62.3%) were genotyped into 21 genotype families while 81 (37.7%) were orphans. The 81 orphans were further subjected to resolution employing SpolDB3/RIM. Overall, the study revealed a high diversity of strains of 32 predominantly the non-Beijing lineages: the LAM- LAM3 (9.8%), LAM9 (4.7%) and LAM11- ZWE (3.3%), the T-T1(15.0%), T2 (0.9%), T2-T3 (1.4%), the CAS-CAS1-Delhi 5 (1.9%) and CAS1-KILI (1.4%) the MANU2 (1.4%), U (0.5%), X-X1(1.4%), X3 (1.9%), S (9.8%), CAS (1.4%), LAM7(0.9%), T3(0.5%), LAM8(4.7%), T4(1.4%), X2(0.4%), AI5(1.9%), LAM1(0.5%), FAMILY33 (1.9%), EAI4(1.4%), M. microti (1.9%). The Beijing and Beijing-like families were (14.9%) and (0.9%), respectively. A total of 28(13%) clusters and 77(36%) unique cases were identified. Beijing strain (SIT 1) formed the biggest cluster constituting 14%, followed by LAM3 (SIT 33), T1 (SIT 53) and LAM4 (SIT 811) with 7%, 5.1% and 2.8%, respectively. The Beijing family was the only genotype found in all the five districts and was predominant in Mopani (18.8%), Sekhukhune (23.7%) and Vhembe (23.3%). Dominant genotypes in Capricorn and Waterberg were LAM3 (11.9%) and T1 (13.3%), respectively.ConclusionA wide diversity of lineages was demonstrated at district level. A high number of clusters per district provided evidence of on-going transmission in this Province.

Molecular Diversity of Mycobacterium tuberculosis Strains in Northwestern Iran.

BackgroundYears after the development of antituberculosis (TB) drugs, many people continue to suffer from this disease. To control the spread of TB, strains of the Mycobacterium tuberculosis complex need to be determined, and sources of infection must be identified. Such steps should help to prevent transmission of the infection.ObjectivesThe aim of this study was to perform molecular genotyping of isolates of the M. tuberculosis complex obtained from patients in northwestern Iran.MethodsOne hundred ninety-four culture-positive M. tuberculosis isolates obtained from patients in northwestern Iran were analyzed using the mycobacterial interspersed repetitive unit-exact tandem repeats (MIRU-ETR) method.ResultsThe MIRU-ETR method distinguished 162 different patterns in the 194 isolates, comprising 23 clusters and 139 unique patterns. Its discriminatory power according to the Hunter-Gaston discriminatory index (HGDI) was 0.9978. The largest cluster contained six isolates.ConclusionsThis research indicated that various strains of M. tuberculosis were responsible for TB and that the majority of cases were due to reactivation.

Genetic diversity of Mycobacterium tuberculosis strains isolated in Algeria: Results of spoligotyping

Objective/backgroundMolecular typing tools, including spoligotyping, are currently widely used in the monitoring and study of the dynamics of tuberculosis epidemics. MethodsA study of the molecular profile of a sample of 129 Myobacterium tuberculosis strains isolated during 2011 was carried out in the National Reference Laboratory for Tuberculosis and Mycobacteria at the Pasteur Institute of Algeria. This sample was selected at random from a set of 350 strains isolated from tuberculosis patients from central and eastern areas of the country. ResultsGenotypic analysis helped to clarify the frequencies of the different genotypes in the current study population: H family, 29%; LAM family, 26%; T family, 25%; S family, 5%, and other genomic families, including orphan strains, 15%. ConclusionThe study of strains isolated between January and December 2011 has allowed insight into the frequency of different genomic families and the importance of existing clusters in the population of central and eastern Algeria.

Drug resistance and molecular epidemiology of Mycobacterium tuberculosis in Mexico: a systematic review.

To compare drug resistance (DR) rates and genetic diversity of Mycobacterium tuberculosis strains from different states of Mexico. A systematic review of English and Spanish-language articles using MEDLINE and Google Scholar. Search terms included Mycobacterium tuberculosis, Mexico, resistance, mutation and epidemiology. Fifteen studies for phenotypic DR rates (n=2 694), twelve studies for genotypic DR (n=748) and eleven studies for genetic diversity (n=2 044) met our inclusion criteria. Mean DR and multidrug resistance (MDR) rates were 37.5% and 20.6%, respectively. The most frequent mutations were rpoB531 (53.1%), katG315 (50.6%), embB306 (32.1%), rpsL43 (14.6%) and pncA359 (16.7%) in DR strains. Novel mutations were found. Predominant shared types were SIT53 (T1, n=188, 3.9%), SIT119 (X1, n=125, 6.9%), SIT19 (EAI2-Manila, n=80, 6.3%) and SIT42 (LAM9, n=77, 3.0%). SIT1 Beijing genotype has been reported in six states from Mexico. DR and MDR rates continue to increase. Genetic diversity of M. tuberculosis strains in Mexico is high. Reports of Beijing strains are increasing.

Molecular Assessment, Drug-Resistant Profile, and Spacer Oligonucleotide Typing (Spoligotyping) ofMycobacterium tuberculosisStrains From Tamaulipas, México

Tuberculosis remains a serious global health problem involving one-third of the world population. A wide diversity of Mycobacterium tuberculosis strains cause about 1.5 million deaths/year worldwide, but in developing countries, the genetic diversity of M. tuberculosis strains remains largely unknown. We conducted a first insight into the population diversity of M. tuberculosis strains from Tamaulipas, Mexico. Seventy-two M. tuberculosis strains were identified and genetic diversity determined by spoligotyping. Drug sensibility testing and punctual mutations in inhA, ahpC, rpoB, and katG genes were assessed. Spoligotyping analysis showed a higher prevalence of LAM9 > T1 > Haarlem3 subfamilies among 53 spoligotype patterns. Unexpectedly, five Beijing strains conforming four unique spoligopatterns were recovered. The more frequently isolated strains (LAM9 and T1), but none of the Beijing strains, were found resistant to INH or RIF. Also, no drug resistance was found among Haarlem3 isolates. The katG(315) gene mutation was found in 83% of INH-resistant strains, whereas rpoB(526) were associated in only 43% of RIF M. tuberculosis drug-resistant strains. This and other studies report a high rate of orphan spoligotypes, which highlights the need for genotyping implementation as a routine technique for better understanding of M. tuberculosis strains in developing countries such as Mexico.

Genotyping and Drug Resistance Patterns of M. tuberculosis in Eastern Amhara region, Ethiopia

Background: Ethiopia is among the countries with the highest incidence of tuberculosis (TB) and has a early incidence of 379 cases/100,000 population. Of the high TB burden regions, Amhara is the top. So understanding the epidemiology of TB through molecular genotyping techniques such as Spoligotyping have invaluable role to combat TB. It will help to designing appropriate intervention and strengthen TB control program. Objectives: To provide insight about the genetic biodiversity of Mycobacterium tuberculosis, strain specific drug susceptibility and possible associated factors in Eastern Amhara region, Ethiopia. Methods: A facility based cross sectional study was conducted among smear positive TB patients (age ≥ 18 years old) from September 2011 to June 2012. Smear positive sputum samples were processed and decontaminated by the modified Petrof method. Primary isolation and drug susceptibility testing (DST) were carried out on egg based Lowenstein-Jensen (LJ). Genotyping of mycobacterial DNA was performed by spoligotyping and isolates were assigned to families using the SpolDB4 and the model-based program ‘Spotclust’. P-values less than 0.05 were considered as statistically significant. Result: The predominant Mycobacterium tuberculosis strains in the present study were ST 149/T3-ETH 49(22.6%), ST53/T1 18(8.3%) and ST50/H3 16(7.4%). T3-ETH strain showed the highest MDR-TB cases. Conclusion: Our finding suggests that a diversity of Mycobacterium tuberculosis strains accompanied with high rate of drug resistance.

Evaluation of Molecular Diversity of Mycobacterium tuberculosis Strains By Polymorphisms in RD Regions

Background: The region of differences (RDs) polymorphisms is a potential molecular epidemiology method to distinguish origins of Mycobacterium tuberculosis (MTB). Till date, 68 RDs were identified in MTB. This study was designed to investigate highly polymorphic regions (RD1, RD150 and RD181) among MTB strains isolates from Iranian Pulmonary tuberculosis patients (PTB). Method and materials: A total of the 190 MTB isolates were identified by conventional and molecular methods. Thereafter, Spoligotyping and RD typing (RD1, RD150 and RD181) were applied to genotype these strains. Results: The most frequent spoligotype belong to Haarlem (n=72, 37.8%) followed by CAS (n=37, 19.4%), T1 (n=18, 9.4%) and Beijing (n=11, 5.7%) lineages. Deletion in RD181 was only identified among Beijing lineage. Conclusion: Deletion in RD181 was prominent among the prevalent Beijing strains in Iran. In this regard, this deletion marker can be used in identification, phylogeny, and molecular epidemiology of the Beijing genotype.

Genetic diversity among multidrug-resistant Mycobacterium tuberculosis strains in Mexico

Tuberculosis is an important public health problem in Mexico. However, limited information about the genetic diversity of Mycobacterium tuberculosis strains circulating in the country is available. In this work, 109 multidrug-resistant (MDR) M. tuberculosis isolates collected in 23 different states of Mexico in 2003 were retrospectively characterized by spoligotyping and MIRU-VNTRs. All isolates, except for a single cluster containing two strains (subcluster E1), were split when information from the 12-loci MIRUs and spoligo-pattern was simultaneously analyzed. The discriminative power of 12-loci MIRU-VNTR and spoligotyping, by the Hunter-Gaston index, were 0.9998 and 0.9011, respectively. These findings suggest that almost all cases were epidemiologically unrelated. Instead, the genetic variations observed among these strains are suggestive of emergence of acquired drug-resistance during the course of treatment. The results suggest a high degree of genetic variability and a high frequency of SIT53 (T1 family) spoligotype among the MDR M. tuberculosis isolates included in the study.

First insight into the genetic diversity of Mycobacterium tuberculosis strains from patients in Duhok, Iraq

BackgroundThe aim of this study was to evaluate the genotypic diversity of Mycobacterium tuberculosis strains using IS6110 RFLP, spoligotyping and MIRU-VNTR typing. Materials and methodsBetween June 2008 and June 2009, all smear positive pulmonary specimens were collected prospectively at the national tuberculosis program (NTP) center of Duhok province. The specimens were processed for culture by modified Petroff’s method and were inoculated into two tubes of Löwenstein-Jensen (LJ) media. The isolates were identified as M. tuberculosis by using biochemical tests and growth rate. Molecular fingerprinting of all M. tuberculosis strains was performed by IS6110 RFLP, spoligotyping and MIRU-VNTR. ResultsM. tuberculosis strains were isolated from 53 Iraqi patients with pulmonary TB. Spoligotyping of M. tuberculosis isolates showed T family (30%) as the predominant genotype. By using the three molecular techniques, there were four spoligotyping clusters of strains (“3540 & 3516”, “3565 & 3563”, “3605 & 3618” and “865, 877 & 13811”). Complete concordance with RFLP was observed in one cluster of spoligotyping, but no concordance with MIRU-VNTR profile (234426153433 and 236424183433). ConclusionsMolecular fingerprinting methods are vital for differentiating a reactivation of latent infection from a recent transmission; however, it should be coupled with clinical epidemiological investigation. The low clustering rate in this study suggests that either reactivation of latent infections may be the main driving force for the endemic situation of the disease in Duhok, or it may indicate that a big circle of TB transmission is missed in the community, which means effective control measures have not been achieved yet in Duhok.

First insights into the genetic diversity of Mycobacterium tuberculosis strains in Salvador, Bahia State, Brazil

This study constitutes a first attempt to describe the genetic population structure of Mycobacterium tuberculosis circulating in Salvador, Bahia State, Brazil. A total of 56 confirmed cases of pulmonary tuberculosis, identified between March and June 2008, were analyzed using restriction fragment length polymorphism (IS6110-RFLP). The study population was characterized by a predominance of males (71.43%) over 30 years of age (68.75%). Forty-one isolates were found to belong to a single pattern (73.2%), while 15 (26.7%) were found in group patterns, forming six clusters. The higher level of diversity observed is much more suggestive of endogenous reactivation than recent transmission.

P1-332 First insight into genetic diversity of Mycobacterium tuberculosis strains in Salvador, Brazil

This study constitutes a first attempt to describe the genetic population structure of M tuberculosis circulating in Salvador. A total of 56 confirmed cases of pulmonary tuberculosis, identified between March...

Genetic diversity of Mycobacterium Tuberculosis strains circulating in Kharkiv Oblast, Ukraine

A molecular genetic study of a tuberculosis mycobacteria isolates obtained from 98 patients with pulmonary tuberculosis residing in the Kharkiv oblast (Ukraine) has been performed for the first time by VNTR and IS6110 RFLP typing methods. Seventy-five different genetic profiles have been identified. Isolates from the Beijing family (34%, 34 isolates) and the LA-M family (23%, 23 isolates) have prevailed. An isolate cluster belonging to the LA-M family has had significant genetic heterogeneity, which indicates the ancient spread and circulation of this family on the studied territory. The strains from the Beijing (31%) and LA-M (14%) families have been mostly spread among the originally detected patients; their frequencies in the group of patients with tuberculosis detected for the second time are 39% and 29%, respectively. An increase in the frequencies of the isolates from these families during chronic tuberculosis have not been statistically significant (χ2 = 0.33, p = 0.56; χ2 = 2.08, p = 0.15, respectively). An association between belonging to the LA-M family and the multidrug resistance of isolates (r = 0.27, p = 0.0059) has been detected. In addition, we have discovered a significant proportion of isolates (36%) that are attributed to yet unidentified families of M. tuberculosis or have individual unclustering genotypes.

First insights into the genetic diversity of Mycobacterium tuberculosis isolates from HIV-infected Mexican patients and mutations causing multidrug resistance

BackgroundThe prevalence of infections with Mycobacterium tuberculosis (MTb) and nontuberculous mycobacteria (NTM) species in HIV-infected patients in Mexico is unknown. The aims of this study were to determine the frequency of MTb and NTM species in HIV-infected patients from Mexico City, to evaluate the genotypic diversity of the Mycobacterium tuberculosis complex strains, to determine their drug resistance profiles by colorimetric microplate Alamar Blue assay (MABA), and finally, to detect mutations present in katG, rpoB and inhA genes, resulting in isoniazid (INH) and rifampin (RIF) resistance.ResultsOf the 67 mycobacterial strains isolated, 48 were identified as MTb, 9 as M. bovis, 9 as M. avium and 1 as M. intracellulare. IS6110-RFLP of 48 MTb strains showed 27 profiles. Spoligotyping of the 48 MTb strains yielded 21 patterns, and 9 M. bovis strains produced 7 patterns. Eleven new spoligotypes patterns were found. A total of 40 patterns were produced from the 48 MTb strains when MIRU-VNTR was performed. Nineteen (39.6%) MTb strains were resistant to one or more drugs. One (2.1%) multidrug-resistant (MDR) strain was identified. A novel mutation was identified in a RIF-resistant strain, GAG → TCG (Glu → Ser) at codon 469 of rpoB gene.ConclusionsThis is the first molecular analysis of mycobacteria isolated from HIV-infected patients in Mexico, which describe the prevalence of different mycobacterial species in this population. A high genetic diversity of MTb strains was identified. New spoligotypes and MIRU-VNTR patterns as well as a novel mutation associated to RIF-resistance were found. This information will facilitate the tracking of different mycobacterial species in HIV-infected individuals, and monitoring the spread of these microorganisms, leading to more appropriate measures for tuberculosis control.

Molecular diversity of Mycobacterium tuberculosis strains in a slum area of Rio de Janeiro, Brazil

This retrospective molecular study involving restriction fragment length polymorphism, using insertion sequence 6110 as a marker, was conducted in order to provide an initial insight into the genetic diversity of Mycobacterium tuberculosis strains isolated in the slums of the Complexo de Manguinhos, located in the city of Rio de Janeiro, Brazil. Of the 67 strains evaluated, 23 (34.3%) were found to belong to clusters (total clusters, 10). Household and social chains of transmission were associated with clustering, in 20% and 60%, respectively. Living in the Conjunto Habitacional Programado 2 slum was associated with clustering. Although not significant, it is relevant that 26% of the clustered strains presented primary resistance. These findings, although possibly underestimating the prevalence due to the failure to analyze all strains, could help improve the local tuberculosis control program.

Molecular epidemiology of Mycobacterium tuberculosis in Lisbon

We conducted a molecular epidemiology study of Mycobacterium tuberculosis strains isolated from patients in Lisbon hospitals. We used restriction fragment length polymorphism (RFLP) to detect Lisbon family strains and to determine the genetic diversity of Mycobacterium tuberculosis strains isolated in Lisbon, through identification of the most important risk factors of tuberculosis transmission analysis, with the insertion sequence IS6110 as a probe to fingerprint isolates of Mycobacterium tuberculosis. 64.8% of the 290 Mycobacterium tuberculosis isolates were grouped in clusters. This figure was 60.7% if we excluded strains with five or fewer IS6110 copies. Multidrug-resistance was observed in 4.1% of the strains and they were all in clusters. Forty-five (18.2%) strains were included in the Lisbon family. Considering the relatively high percentage of strains in cluster detected in this study, we believe that active transmission is still taking place in Lisbon. Moreover, clusters of Lisbon strains represent the predominant strains circulating in Lisbon and are still related to drug resistance although presenting a lower percentage than that observed in previous studies.

Epidemiologia molecular de Mycobacterium tuberculosis em Lisboa

We conducted a molecular epidemiology study of Mycobacterium tuberculosis strains isolated from patients in Lisbon hospitals. We used restriction fragment length polymorphism (RFLP) to detect Lisbon family strains and to determine the genetic diversity of Mycobacterium tuberculosis strains isolated in Lisbon, through identification of the most important risk factors of tuberculosis transmission analysis, with the insertion sequence IS6110 as a probe to fingerprint isolates of Mycobacterium tuberculosis. 64.8% of the 290 Mycobacterium tuberculosis isolates were grouped in clusters. This figure was 60.7% if we excluded strains with five or fewer IS6110 copies. Multidrug-resistance was observed in 4.1% of the strains and they were all in clusters. Forty-five (18.2%) strains were included in the Lisbon family. Considering the relatively high percentage of strains in cluster detected in this study, we believe that active transmission is still taking place in Lisbon. Moreover, clusters of Lisbon strains represent the predominant strains circulating in Lisbon and are still related to drug resistance although presenting a lower percentage than that observed in previous studies.Rev Port Pneumol 2007; XIV (2): 239-259