-
[show abstract]
[hide abstract]
ABSTRACT: The opportunistic fungal pathogen Candida glabrata adheres tightly to epithelial cells in culture, mainly through the adhesin Epa1. EPA1 is the founding member of a family of up to 23 putative adhesin-encoding genes present in the C. glabrata genome. The majority of the EPA genes are localized close to the telomeres, where they are repressed by subtelomeric silencing that depends on the Sir, Ku, Rif1, and Rap1 proteins. EPA6 and EPA7 also encode functional adhesins that are repressed in vitro. EPA1 expression in vitro is tightly controlled both positively and negatively, and in addition, presents high cell-to-cell heterogeneity, which depends on Sir-mediated silencing. In this work, we characterized the ability to adhere to HeLa epithelial cells and the expression of several EPA genes in a collection of 79 C. glabrata clinical isolates from several hospitals in Mexico. We found 11 isolates that showed increased adherence to mammalian cells compared with our reference strain under conditions where EPA1 is not expressed. The majority of these isolates displayed over-expression of EPA1 and EPA6 or EPA7, but did not show increased biofilm formation. Sequencing of the SIR3 gene of several hyper-adherent isolates revealed that all of them contain several polymorphisms with respect to the reference strain. Interestingly, two isolates have polymorphisms in positions flanked by clusters of amino acids required for silencing in the Saccharomyces cerevisiae Sir3 protein. Our data show that there is a large variability in adhesin expression and adherence to epithelial cells among different C. glabrata clinical isolates.
Mycopathologia 02/2013; · 1.65 Impact Factor
-
María Eugenia Jiménez-Corona,
Luis Pablo Cruz-Hervert,
Lourdes García-García,
Leticia Ferreyra-Reyes,
Guadalupe Delgado-Sánchez,
Miriam Bobadilla-Del-Valle,
Sergio Canizales-Quintero,
Elizabeth Ferreira-Guerrero,
Renata Báez-Saldaña,
Norma Téllez-Vázquez,
Rogelio Montero-Campos,
Norma Mongua-Rodriguez,
Rosa Areli Martínez-Gamboa,
José Sifuentes-Osornio, Alfredo Ponce-de-León
[show abstract]
[hide abstract]
ABSTRACT: OBJECTIVE: To determine the clinical consequences of pulmonary tuberculosis (TB) among patients with diabetes mellitus (DM). METHODS: We conducted a prospective study of patients with TB in Southern Mexico. From 1995 to 2010, patients with acid-fast bacilli or Mycobacterium tuberculosis in sputum samples underwent epidemiological, clinical and microbiological evaluation. Annual follow-ups were performed to ascertain treatment outcome, recurrence, relapse and reinfection. RESULTS: The prevalence of DM among 1262 patients with pulmonary TB was 29.63% (n=374). Patients with DM and pulmonary TB had more severe clinical manifestations (cavities of any size on the chest x-ray, adjusted OR (aOR) 1.80, 95% CI 1.35 to 2.41), delayed sputum conversion (aOR 1.51, 95% CI 1.09 to 2.10), a higher probability of treatment failure (aOR 2.93, 95% CI 1.18 to 7.23), recurrence (adjusted HR (aHR) 1.76, 95% CI 1.11 to 2.79) and relapse (aHR 1.83, 95% CI 1.04 to 3.23). Most of the second episodes among patients with DM were caused by bacteria with the same genotype but, in 5/26 instances (19.23%), reinfection with a different strain occurred. CONCLUSIONS: Given the growing epidemic of DM worldwide, it is necessary to add DM prevention and control strategies to TB control programmes and vice versa and to evaluate their effectiveness. The concurrence of both diseases potentially carries a risk of global spreading, with serious implications for TB control and the achievement of the United Nations Millennium Development Goals.
Thorax 12/2012; · 6.84 Impact Factor
-
Christian Hernández-León,
Florentino Badial-Hernández, Alfredo Ponce-de-León,
Juan G Sierra-Madero,
Areli Martínez-Gamboa,
Brenda Crabtree-Ramírez,
Sergio Bautista-Arredondo,
Adrián González-Aguirre,
María de Lourdes Guerrero-Almeida,
J Miriam Bobadilla Del Valle,
Andrea González-Rodríguez,
José Sifuentes-Osornio
[show abstract]
[hide abstract]
ABSTRACT: To determine the clinical and epidemiological characteristics of prison inmates with active tuberculosis in HIV-positive prison populations.
We conducted a cohort study in HIV-infected subjects in a prison in Mexico City, with the aim of determining clinical and epidemiological characteristics of cases with active TB.
We detected 172 HIV infected inmates and TB in 28 of them (16.3%) - 21 (12.2) with pulmonary TB - with an incidence rate of 7.7/100 persons/year for active TB and 4.7/100 persons/year for pulmonary TB. No drug resistance was found. Two clusters (4 and 2 subjects) were observed after RFLP-typing of 18 isolates, with a transmission rate of 11% by molecular and clinical analysis.
The prevalence of active TB was found to be a thousand times greater than in the general population. Evidence of transmission inside the prison was also found.
Salud publica de Mexico 12/2012; 54(6):571-8. · 0.94 Impact Factor
-
Robert A Bonacci,
Luis Pablo Cruz-Hervert,
Lourdes García-García,
Luz Myriam Reynales-Shigematsu,
Leticia Ferreyra-Reyes,
Miriam Bobadilla-Del-Valle,
Sergio Canizales-Quintero,
Elizabeth Ferreira-Guerrero,
Renata Báez-Saldaña,
Norma Téllez-Vázquez,
Norma Mongua-Rodríguez,
Rogelio Montero-Campos,
Guadalupe Delgado-Sánchez,
Rosa Areli Martínez-Gamboa,
Bulmaro Cano-Arellano,
José Sifuentes-Osornio, Alfredo Ponce de León
[show abstract]
[hide abstract]
ABSTRACT: OBJECTIVES: To examine the relationship between cigarette smoking and incidence and mortality rates of pulmonary tuberculosis (TB) and treatment outcomes. MATERIALS: From 1995 to 2010, we analyzed data from 1062 patients with TB and from 2001 to 2004, 2951 contacts in Southern Mexico. Patients with acid-fast bacilli or Mycobacterium tuberculosis in sputum samples underwent epidemiological, clinical and mycobacteriological evaluation and received treatment by the local DOTS program. RESULTS: Consumers of 1-10 (LS) or 11 or more (HS) cigarettes per day incidence (1.75 and 11.79) and mortality (HS, 17.74) smoker-non-smoker rate ratios were significantly higher for smokers. Smoker population was more likely to experience unfavorable treatment outcomes (HS, adjusted OR 2.36) and retreatment (LS and HS, adjusted hazard ratio (HR) 2.14 and 2.37). Contacts that smoked had a higher probability of developing active TB (HR 2.38) during follow up. CONCLUSIONS: Results indicate the need of incorporating smoking prevention and cessation, especially among men, into international TB control strategies.
The Journal of infection 09/2012; · 4.13 Impact Factor
-
Luis Pablo Cruz-Hervert,
Lourdes García-García,
Leticia Ferreyra-Reyes,
Miriam Bobadilla-del-Valle,
Bulmaro Cano-Arellano,
Sergio Canizales-Quintero,
Elizabeth Ferreira-Guerrero,
Renata Báez-Saldaña,
Norma Téllez-Vázquez,
Ariadna Nava-Mercado,
Luis Juárez-Sandino,
Guadalupe Delgado-Sánchez,
César Alejandro Fuentes-Leyra,
Rogelio Montero-Campos,
Rosa Areli Martínez-Gamboa,
Peter M Small,
José Sifuentes-Osornio, Alfredo Ponce-de-León
[show abstract]
[hide abstract]
ABSTRACT: worldwide, the frequency of tuberculosis among older people almost triples that observed among young adults.
to describe clinical and epidemiological consequences of pulmonary tuberculosis among older people.
we screened persons with a cough lasting more than 2 weeks in Southern Mexico from March 1995 to February 2007. We collected clinical and mycobacteriological information (isolation, identification, drug-susceptibility testing and IS6110-based genotyping and spoligotyping) from individuals with bacteriologically confirmed pulmonary tuberculosis. Patients were treated in accordance with official norms and followed to ascertain treatment outcomes, retreatment, and vital status.
eight hundred ninety-three tuberculosis patients were older than 15 years of age; of these, 147 (16.5%) were 65 years of age or older. Individuals ≥ 65 years had significantly higher rates of recently transmitted and reactivated tuberculosis. Older age was associated with treatment failure (OR=5.37; 95% CI: 1.06-27.23; P=0.042), and death due to tuberculosis (HR=3.52; 95% CI: 1.78-6.96; P<0.001) adjusting for sociodemographic and clinical variables.
community-dwelling older individuals participate in chains of transmission indicating that tuberculosis is not solely due to the reactivation of latent disease. Untimely and difficult diagnosis and a higher risk of poor outcomes even after treatment completion emphasise the need for specific strategies for this vulnerable group.
Age and Ageing 03/2012; 41(4):488-95. · 3.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The aim of the article is to describe the principal findings among patients with M.tuberculosis and M. bovis CNS infection. Mycobacterium tuberculosis is one of the most common infectious agents that cause death and neurological sequelae around the world. Most of the complications of CNS TB can be attributed to a delay in the diagnosis. Unfortunately, there are no specific diagnostic tools to support an early diagnosis. Other prognostic factors different from delay in treatment have not been identified. Clinical, radiological and laboratory characteristics were analyzed retrospectively from the medical files of all the patients admitted with the diagnoses of tuberculosis. Of 215 patients admitted with systemic tuberculosis, 64 (30%) had a neurological infection. Positive cultures were found in 54 (84%) cases, 18 (33%) in the CSF and the rest in other fluids or tissues. Adenosin deaminase (ADA) enzyme determination was more sensitive than M. tuberculosis PCR in the CSF for supporting an early diagnosis. In addition to a later clinical stage and treatment lag, positive CSF cultures (P=0.001) and the presence of M. bovis (P=0.020) were prognostic factors for a worse outcome. Neither older age, the presence of tuberculomas versus meningeal enhancement, or HIV co-infection, was associated to a worse prognosis. The isolation of M. bovis subspecies was more common that previously reported, and it was associated to the development of parenchymal lesions (P=0.032) when compared to M. tuberculosis. In this study, positive CSF cultures for M. tuberculosis and further identifying M. bovis species were additional prognostic factors for worse outcome. Positive cultures in systemic fluids other than CSF, even when the patient had no obvious systemic manifestations, and ADA determination in the CSF were noteworthy diagnostic tools for the diagnosis.
Neurology International 11/2011; 3(3):e9.
-
[show abstract]
[hide abstract]
ABSTRACT: The diagnosis of Clostridium difficile-associated disease (CDAD) is based on the detection of toxins from stool samples. There are several immunoassays for this purpose. The aim of this study was to determine the concordance between the two immunoassays and their performance in comparison to the toxigenic culture as part of the initial evaluation of a suspected case of CDAD.
All fecal samples submitted for detection of C. difficile toxins during a 5-month period to our laboratory were analyzed by two immunoassays, VIDAS Toxin CDA/B assay (BioMerieux) and ImmunoCard Toxins A/B (Meridian Bioscience). We cultured on cycloserine-cefoxitin-fructose agar and PCR was used for detection of toxigenic genes. Real-time PCR was performed directly from samples to detect the tcdC gene.
At the end of the study we processed 230 samples, 13 were positive using VIDAS CDA/B (5.6%), and 14 using ImmunoCard A/B (6.0%); kappa coefficient was 0.857. With ImmunoCard A/B we obtained a sensitivity of 80%, a specificity of 99%, positive predictive value (PPV) 86% and negative predictive value (NPV) 98%, as compared to toxigenic culture. For VIDAS CDA/B we obtained a sensitivity of 90%, a specificity of 98%, PPV 69% and NPV 99%, compared to the same standard. There were seven undetermined results (3.0%) by VIDAS CDA/B. Five of these had a positive culture and all the patients had symptoms of CDAD. Considering these undetermined results as positive, we calculated a sensitivity of 93%, specificity of 97%, PPV 71% and NPV of 99% for this test, and a kappa of 0.856. Both immunoassays showed similar results and are suitable for the initial evaluation of patients with suspected CDAD.
Our data suggest that an undetermined result of VIDAS CDA/B should be considered as positive if CDAD is suspected. Additionally, both immunoassays showed similar results and are suitable for the initial evaluation of patients with suspected CDAD.
Archives of medical research 02/2010; 41(2):92-6. · 1.88 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The opportunistic fungal pathogen Candida glabrata is the second most common isolate from bloodstream infections worldwide and is naturally less susceptible to the antifungal drug fluconazole than other Candida species. C. glabrata is a haploid yeast that contains three mating-type like loci (MTL), although no sexual cycle has been described. Strains containing both types of mating information at the MTL1 locus are found in clinical isolates, but it is thought that strains containing type a information are more common. Here we investigated if a particular combination of mating type information at each MTLlocus is more prevalent in clinical isolates from hospitalized patients in Mexico and if there is a correlation between mating information and resistance to fluconazole and 5-fluorocytosine. We found that while both types of information at MTL1 are equally represented in a collection of 64 clinical isolates, the vast majority of isolates contain a-type information at MTL2 and alpha-type at MTL3. We also found no correlation of the particular combination of mating type information at the three MTL loci and resistance to fluconazole.
Memórias do Instituto Oswaldo Cruz 08/2009; 104(5):775-82. · 2.15 Impact Factor
-
Ma Eugenia Jiménez-Corona,
Lourdes García-García, Alfredo Ponce de León,
Miriam Bobadilla-del Valle,
Martha Torres,
Sergio Canizales-Quintero,
Carmen Palacios-Merino,
Susana Molina-Hernández,
Rosa Areli Martínez-Gamboa,
Luis Juárez-Sandino,
Bulmaro Cano-Arellano,
Leticia Ferreyra-Reyes
[show abstract]
[hide abstract]
ABSTRACT: This study describes the achievements of the Mexican Consortium against Tuberculosis, in the Sanitary District of Orizaba, Veracruz, Mexico between 1995 and 2008. In brief, the main results can be classified as follows: 1) Conventional and molecular epidemiology (measurement of burden of disease, trends, risk factors and vulnerable groups, conse- quences of drug resistance, identification of factors that favor nosocomial and community transmission); 2) Development of diagnostic techniques to detect drug resistance, description of circulating clones and adaptation of simple techniques to be used in the field; 3) Evaluation of usefulness of tuberculin skin test, immunologic responses to BCG, impact of directly observed therapy for tuberculosis (DOTS), and study of im- munological biomarkers and 4) Comments on ethical aspects of tuberculosis research. Additionally, we describe the impact on public policies, transference of technology, capacity building and future perspectives.
Salud publica de Mexico 01/2009; 51. · 0.94 Impact Factor
-
Brenda Marquina-Castillo,
Lourdes García-García, Alfredo Ponce-de-León,
Maria-Eugenia Jimenez-Corona,
Miriam Bobadilla-Del Valle,
Bulmaro Cano-Arellano,
Sergio Canizales-Quintero,
Areli Martinez-Gamboa,
Midori Kato-Maeda,
Brian Robertson,
Douglas Young,
Peter Small,
Gary Schoolnik,
Jose Sifuentes-Osornio,
Rogelio Hernandez-Pando
[show abstract]
[hide abstract]
ABSTRACT: After encounter with Mycobacterium tuberculosis, a series of non-uniform immune responses are triggered that define the course of the infection. Eight M. tuberculosis strains were selected from a prospective population-based study of pulmonary tuberculosis patients (1995-2003) based on relevant clinical/epidemiological patterns and tested in a well-characterized BALB/c mouse model of progressive pulmonary tuberculosis. In addition, a new mouse model of transmissibility consisting of prolonged cohousing (up to 60 days) of infected and naïve animals was tested. Four phenotypes were defined based on strain virulence (mouse survival, lung bacillary load and tissue damage), immunology response (cytokine expression determined by real-time polymerase chain reaction) and transmissibility (lung bacillary loads and cutaneous delayed-type hypersensitivity in naïve animals).We identified four clearly defined strain phenotypes: (1) hypervirulent strain with non-protective immune response and highly transmissible; (2) virulent strain, associated with high expression of proinflammatory cytokines (tumour necrosis factor and interferon) and very low anti-inflammatory cytokine expression (interleukins 4 and 10), which induced accelerated death by immunopathology; (3) strain inducing efficient protective immunity with lower virulence, and (4) strain demonstrating strong and early macrophage activation (innate immunity) with delayed participation of acquired immunity (interferon expression). We were able to correlate virulent and transmissible phenotypes in the mouse model and markers of community transmission such as tuberculin reactivity among contacts, rapid progression to disease and cluster status. However, we were not able to find correlation with the other two phenotypes. Our new transmission model supported the hypothesis that among these strains increased virulence was linked to increased transmission.
Immunology 01/2009; 128(1):123-33. · 3.32 Impact Factor
-
Ma Eugenia Jiménez-Corona,
Lourdes García-García, Alfredo Ponce de León,
Miriam Bobadilla-del Valle,
Martha Torres,
Sergio Canizales-Quintero,
Carmen Palacios-Merino,
Susana Molina-Hernández,
Rosa Areli Martínez-Gamboa,
Luis Juárez-Sandino,
Bulmaro Cano-Arellano,
Leticia Ferreyra-Reyes,
Luis Pablo Cruz-Hervert,
Renata Báez-Saldaña,
Elizabeth Ferreira-Guerrero,
Eduardo Sada,
Brenda Marquina,
José Sifuentes-Osornio
[show abstract]
[hide abstract]
ABSTRACT: This study describes the achievements of the Mexican Consortium against Tuberculosis, in the Sanitary District of Orizaba, Veracruz, Mexico between 1995 and 2008. In brief, the main results can be classified as follows: 1) Conventional and molecular epidemiology (measurement of burden of disease, trends, risk factors and vulnerable groups, consequences of drug resistance, identification of factors that favor nosocomial and community transmission); 2) Development of diagnostic techniques to detect drug resistance, description of circulating clones and adaptation of simple techniques to be used in the field; 3) Evaluation of usefulness of tuberculin skin test, immunologic responses to BCG, impact of directly observed therapy for tuberculosis (DOTS), and study of immunological biomarkers and 4) Comments on ethical aspects of tuberculosis research. Additionally, we describe the impact on public policies, transference of technology, capacity building and future perspectives.
Salud publica de Mexico 01/2009; 51 Suppl 3:S470-8. · 0.94 Impact Factor
-
Juan L Mosqueda-Gómez,
Aldo Montaño-Loza,
Ana L Rolón,
Carlos Cervantes,
J Miriam Bobadilla-del-Valle,
Jesús Silva-Sánchez,
Ulises Garza-Ramos,
Angelina Villasís-Keever,
Arturo Galindo-Fraga,
Guillermo M Ruiz Palacios, Alfredo Ponce-de-León,
José Sifuentes-Osornio
[show abstract]
[hide abstract]
ABSTRACT: To study the prevalence, risk factors, outcome, and molecular epidemiology in patients with bacteremia caused by extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae (Kp) (cases), in comparison with patients with bacteremia caused by a susceptible Kp (controls).
This was a retrospective case-control study including all episodes of Kp bacteremia for the period 1993 to 2002 at a referral hospital for adults in Mexico. ESBL production was tested for by E-test. All isolates were typed by pulsed field gel electrophoresis (PFGE). A subset of isolates underwent plasmid analysis, conjugal transfer of cefotaxime resistance to Escherichia coli J53-2, isoelectric focusing bioassay, colony-blot hybridization, PCR, and sequencing.
Of the 121 patients with bacteremia due to Kp included in the study, 17 (14.0%) had an ESBL-Kp isolate (cases). Multivariate analysis identified prior use of cephalosporins (OR 7.6, 95% CI 1.1-53.5; p=0.039) and stay in the intensive care unit (ICU; OR 5.6, 95% CI 1.1-27.9; p=0.033) as significant risk factors. No differences were observed in hospital stay or mortality after the event. Multi-drug resistance was more frequent in ESBL-Kp. There was no clonal predominance. A distinct beta-lactamase profile was identified, which included a combination of TEM-1 (pI 5.4) and SHV-5 (pI 8.2) in 13/17 ESBL-Kp isolates. Cefotaxime resistance was transferred by conjugation in 14/17 isolates with a >120-kb plasmid encoding ESBL.
The prevalence of ESBL-Kp was found to be lower than that previously reported in Latin America. ESBL-Kp bacteremia was not associated with a worse clinical outcome. We were able to identify a plasmid-mediated horizontal dissemination over the 10-year period.
International journal of infectious diseases: IJID: official publication of the International Society for Infectious Diseases 06/2008; 12(6):653-9. · 2.17 Impact Factor
-
Jennifer Cuellar-Rodríguez,
Arturo Galindo-Fraga,
Víctor Guevara,
Carolina Pérez-Jiménez,
Luis Espinosa-Aguilar,
Ana Lilia Rolón,
Araceli Hernández-Cruz,
Esaú López-Jácome,
Miriam Bobadilla-del-Valle,
Areli Martínez-Gamboa, Alfredo Ponce-de-León,
José Sifuentes-Osornio
Emerging infectious diseases 06/2007; 13(5):798-9. · 6.17 Impact Factor
-
Ma Cecilia García-Sancho F,
Lourdes García-García,
Ma Eugenia Jiménez-Corona,
Manuel Palacios-Martínez,
Leticia D Ferreyra-Reyes,
Sergio Canizales-Quintero,
Bulmaro Cano-Arellano, Alfredo Ponce-de-León,
José Sifuentes-Osornio,
Peter Small,
Kathryn DeRiemer
[show abstract]
[hide abstract]
ABSTRACT: The tuberculin skin test (TST) is the most commonly used tool to detect infection with Mycobacterium tuberculosis. We sought to determine whether tuberculin skin testing is useful to detect latent infection by M. tuberculosis in a population that was vaccinated with the Bacille Calmette Guérin (BCG) vaccine.
We performed a cross-sectional study during October 2000-February 2001, enrolling first and sixth graders from a random, stratified sample of public elementary schools in Orizaba, Veracruz, Mexico. We assessed the relationship between sociodemographic and epidemiological information, BCG scars, and TST reactivity.
There were 858 children enrolled in the study with a completed questionnaire and TST result. The prevalence of a positive TST result (> or =10 mm) was 12.4%. Controlling for BCG scar, age, and other characteristics, close contact with pulmonary tuberculosis patients (odds ratio 6.56, 95% confidence interval 2.05-21.07, P = 0.001) was independently associated with TST reactivity.
TST results helped identify children in a BCG-vaccinated population who had recent exposure to persons with pulmonary tuberculosis, were probably infected with M. tuberculosis, and could benefit from treatment for their latent tuberculosis infection.
International Journal of Epidemiology 12/2006; 35(6):1447-54. · 6.41 Impact Factor
-
Manzour Hernando Hazbón,
Michael Brimacombe,
Miriam Bobadilla del Valle,
Magali Cavatore,
Marta Inírida Guerrero,
Mandira Varma-Basil,
Helen Billman-Jacobe,
Caroline Lavender,
Janet Fyfe,
Lourdes García-García,
Clara Inés León,
Mridula Bose,
Fernando Chaves,
Megan Murray,
Kathleen D Eisenach,
José Sifuentes-Osornio,
M Donald Cave, Alfredo Ponce de León,
David Alland
[show abstract]
[hide abstract]
ABSTRACT: The molecular basis for isoniazid resistance in Mycobacterium tuberculosis is complex. Putative isoniazid resistance mutations have been identified in katG, ahpC, inhA, kasA, and ndh. However, small sample sizes and related potential biases in sample selection have precluded the development of statistically valid and significant population genetic analyses of clinical isoniazid resistance. We present the first large-scale analysis of 240 alleles previously associated with isoniazid resistance in a diverse set of 608 isoniazid-susceptible and 403 isoniazid-resistant clinical M. tuberculosis isolates. We detected 12 mutant alleles in isoniazid-susceptible isolates, suggesting that these alleles are not involved in isoniazid resistance. However, mutations in katG, ahpC, and inhA were strongly associated with isoniazid resistance, while kasA mutations were associated with isoniazid susceptibility. Remarkably, the distribution of isoniazid resistance-associated mutations was different in isoniazid-monoresistant isolates from that in multidrug-resistant isolates, with significantly fewer isoniazid resistance mutations in the isoniazid-monoresistant group. Mutations in katG315 were significantly more common in the multidrug-resistant isolates. Conversely, mutations in the inhA promoter were significantly more common in isoniazid-monoresistant isolates. We tested for interactions among mutations and resistance to different drugs. Mutations in katG, ahpC, and inhA were associated with rifampin resistance, but only katG315 mutations were associated with ethambutol resistance. There was also a significant inverse association between katG315 mutations and mutations in ahpC or inhA and between mutations in kasA and mutations in ahpC. Our results suggest that isoniazid resistance and the evolution of multidrug-resistant strains are complex dynamic processes that may be influenced by interactions between genes and drug-resistant phenotypes.
Antimicrobial Agents and Chemotherapy 09/2006; 50(8):2640-9. · 4.84 Impact Factor
-
Ingrid Filliol,
Alifiya S Motiwala,
Magali Cavatore,
Weihong Qi,
Manzour Hernando Hazbón,
Miriam Bobadilla del Valle,
Janet Fyfe,
Lourdes García-García,
Nalin Rastogi,
Christophe Sola, [......],
Kathleen D Eisenach,
Riza Durmaz,
Moses L Joloba,
Adrian Rendón,
José Sifuentes-Osornio, Alfredo Ponce de León,
M Donald Cave,
Robert Fleischmann,
Thomas S Whittam,
David Alland
[show abstract]
[hide abstract]
ABSTRACT: We analyzed a global collection of Mycobacterium tuberculosis strains using 212 single nucleotide polymorphism (SNP) markers. SNP nucleotide diversity was high (average across all SNPs, 0.19), and 96% of the SNP locus pairs were in complete linkage disequilibrium. Cluster analyses identified six deeply branching, phylogenetically distinct SNP cluster groups (SCGs) and five subgroups. The SCGs were strongly associated with the geographical origin of the M. tuberculosis samples and the birthplace of the human hosts. The most ancestral cluster (SCG-1) predominated in patients from the Indian subcontinent, while SCG-1 and another ancestral cluster (SCG-2) predominated in patients from East Asia, suggesting that M. tuberculosis first arose in the Indian subcontinent and spread worldwide through East Asia. Restricted SCG diversity and the prevalence of less ancestral SCGs in indigenous populations in Uganda and Mexico suggested a more recent introduction of M. tuberculosis into these regions. The East African Indian and Beijing spoligotypes were concordant with SCG-1 and SCG-2, respectively; X and Central Asian spoligotypes were also associated with one SCG or subgroup combination. Other clades had less consistent associations with SCGs. Mycobacterial interspersed repetitive unit (MIRU) analysis provided less robust phylogenetic information, and only 6 of the 12 MIRU microsatellite loci were highly differentiated between SCGs as measured by GST. Finally, an algorithm was devised to identify two minimal sets of either 45 or 6 SNPs that could be used in future investigations to enable global collaborations for studies on evolution, strain differentiation, and biological differences of M. tuberculosis.
Journal of Bacteriology 02/2006; 188(2):759-72. · 3.83 Impact Factor
-
Manzour Hernando Hazbón,
Miriam Bobadilla del Valle,
Marta Inírida Guerrero,
Mandira Varma-Basil,
Ingrid Filliol,
Magali Cavatore,
Roberto Colangeli,
Hassan Safi,
Helen Billman-Jacobe,
Caroline Lavender, [......],
Michael Brimacombe,
Clara Inés León,
Tania Porras,
Mridula Bose,
Fernando Chaves,
Kathleen D Eisenach,
José Sifuentes-Osornio, Alfredo Ponce de León,
M Donald Cave,
David Alland
[show abstract]
[hide abstract]
ABSTRACT: Mutations at position 306 of embB (embB306) have been proposed as a marker for ethambutol resistance in Mycobacterium tuberculosis; however, recent reports of embB306 mutations in ethambutol-susceptible isolates caused us to question the biological role of this mutation. We tested 1,020 clinical M. tuberculosis isolates with different drug susceptibility patterns and of different geographical origins for associations between embB306 mutations, drug resistance patterns, and major genetic group. One hundred isolates (10%) contained a mutation in embB306; however, only 55 of these mutants were ethambutol resistant. Mutations in embB306 could not be uniquely associated with any particular type of drug resistance and were found in all three major genetic groups. A striking association was observed between these mutations and resistance to any drug (P < 0.001), and the association between embB306 mutations and resistance to increasing numbers of drugs was highly significant (P < 0.001 for trend). We examined the association between embB306 mutations and IS6110 clustering (as a proxy for transmission) among all drug-resistant isolates. Mutations in embB306 were significantly associated with clustering by univariate analysis (odds ratio, 2.44; P = 0.004). In a multivariate model that also included mutations in katG315, katG463, gyrA95, and kasA269, only mutations in embB306 (odds ratio, 2.14; P = 0.008) and katG315 (odds ratio, 1.99; P = 0.015) were found to be independently associated with clustering. In conclusion, embB306 mutations do not cause classical ethambutol resistance but may predispose M. tuberculosis isolates to the development of resistance to increasing numbers of antibiotics and may increase the ability of drug-resistant isolates to be transmitted between subjects.
Antimicrobial Agents and Chemotherapy 09/2005; 49(9):3794-802. · 4.84 Impact Factor
-
Mandira Varma-Basil,
Hiyam El-Hajj,
Roberto Colangeli,
Manzour Hernando Hazbón,
Sujeet Kumar,
Mridula Bose,
Miriam Bobadilla-del-Valle,
Lourdes García García,
Araceli Hernández,
Fred Russell Kramer,
Jose Sifuentes Osornio, Alfredo Ponce-de-León,
David Alland
[show abstract]
[hide abstract]
ABSTRACT: We assessed the performance of a rapid, single-well, real-time PCR assay for the detection of rifampin-resistant Mycobacterium tuberculosis by using clinical isolates from north India and Mexico, regions with a high incidence of tuberculosis. The assay uses five differently colored molecular beacons to determine if a short region of the M. tuberculosis rpoB gene contains mutations that predict rifampin resistance in most isolates. Until now, the assay had not been sufficiently tested on samples from countries with a high incidence of tuberculosis. In the present study, the assay detected mutations in 16 out of 16 rifampin-resistant isolates from north India (100%) and in 55 of 64 rifampin-resistant isolates from Mexico (86%) compared to results with standard susceptibility testing. The assay did not detect mutations (a finding predictive of rifampin susceptibility) in 37 out of 37 rifampin-susceptible isolates from India (100%) and 125 out of 126 rifampin-susceptible isolates from Mexico (99%). DNA sequencing revealed that none of the nine rifampin-resistant isolates from Mexico, which were misidentified as rifampin susceptible by the molecular beacon assay, contained a mutation in the region targeted by the molecular beacons. The one rifampin-susceptible isolate from Mexico that appeared to be rifampin resistant by the molecular beacon assay contained an S531W mutation, which is usually associated with rifampin resistance. Of the rifampin-resistant isolates that were correctly identified in the molecular beacon assay, one contained a novel L530A mutation and another contained a novel deletion between codons 511 and 514. Overall, the molecular beacon assay appears to have sufficient sensitivity (89%) and specificity (99%) for use in countries with a high prevalence of tuberculosis.
Journal of Clinical Microbiology 01/2005; 42(12):5512-6. · 4.15 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To describe the molecular epidemiology of tuberculosis (TB)-related deaths in a well-managed program in a low-HIV area, we analyzed data from a cohort of 454 pulmonary TB patients recruited between March 1995 and October 2000 in southern Mexico. Patients who were sputum acid-fast bacillus smear positive underwent clinical and mycobacteriologic evaluation (isolation, identification, drug-susceptibility testing, and IS6110-based genotyping and spoligotyping) and received treatment from the local directly observed treatment strategy (DOTS) program. After an average of 2.3 years of follow-up, death was higher for clustered cases (28.6 vs. 7%, p=0.01). Cox analysis revealed that TB-related mortality hazard ratios included treatment default (8.9), multidrug resistance (5.7), recently transmitted TB (4.1), weight loss (3.9), and having less than 6 years of formal education (2). In this community, TB is associated with high mortality rates.
Emerging infectious diseases 12/2002; 8(11):1327-33. · 6.17 Impact Factor
-
Midori Kato Maeda,
Miriam Bobadilla Del Valle,
Areli Martínez Gamboa,
Araceli Hernández Cruz,
Isabel Ramírez Mora,
Norma Cerón Enríquez,
Narciso Ortiz Conchi,
Luis Rodrigo Macías Kauffer,
Rodrigo Toral Villanueva, Alfredo Ponce de León,
José Sifuentes Osornio
[show abstract]
[hide abstract]
ABSTRACT: To evaluate the efficacy of PCR in the diagnosis of extrapulmonary tuberculosis (TB) and its impact in the management of patients in a tertiary-care center in Mexico City.
We conducted a retrospective study based on 40 clinical charts of patients to whom nested PCR was performed for the diagnosis of TB from June 1999 to December 2000. We reviewed the medical notes of 10 days before and 10 days after the PCR study to analyze its impact in the management of the patient. Also, we reviewed the rest of the chart to decide if the patient suffered from TB or not (gold standard). The categories of diagnosis were definitive case of TB, probable TB and no TB. We calculated the sensitivity, specificity, and predictive values.
The PCR was positive in 45% of the cases. The sensitivity of PCR to diagnosis TB was 50%, specificity 59%, and the positive and negative predictive value were 35% and 72%, respectively. If just spinal fluid was included, the sensitivity and the negative predictive value increased to 75% and 63%, respectively. The PCR had an impact in the management of 13% of the patients.
The PCR for the diagnosis of extrapulmonary TB has limited efficacy, which improves when the test is done in spinal fluid samples. The impact of the result of PCR in the clinical management of the patients was poor.
Revista de investigacion clinica; organo del Hospital de Enfermedades de la Nutricion 54(6):509-14. · 0.42 Impact Factor
