Martha Isabel Murcia

A first insight on the population structure of Mycobacterium tuberculosis complex as studied by spoligotyping and MIRU-VNTRs in Bogotá, Colombia.

With an incidence of 25.6/100,000 in 2008, tuberculosis (TB) remains an important public health problem in Colombia. In this study, a total of 152 Mycobacterium tuberculosis complex strains isolated in Bogotá, Colombia between years 1995 and 2007 were genotyped by spoligotyping and 12-loci MIRU-VNTRs. The various spoligotyping-based genotypic lineages in our sample were: Latin American & Mediterranean (LAM) n=75, 49.34%; Haarlem, n=38, 25.0%; ill-defined T group, n=21, 13.82%; S family, n=5, 3.29%; X clade, n=2, 1.32%; Beijing, n=1, 0.65%, while strains with unknown signatures (n=10) represented 6.58% of isolates. Using spoligotyping as a first molecular marker and MIRU-VNTRs as second marker, we obtained 102 single patterns and 14 clustered patterns (n=52 strains from 49 patients, 2-8 strains per cluster). The MIRU-VNTRs patterns corresponded to 50 MITs for 109 strains and 43 orphan patterns. The most frequent patterns were MIT190 (n=12), MIT45 (n=10), and MIT25 (n=9). The Hunter & Gaston discriminatory index (HGDI) of both methodologies used together showed a value of 0.992. In our setting, the HGDI of five loci subset (MIRU10, 16, 23, 26 and 40) contributed most to the discriminatory power of 12-loci format used (HGDI=0.977). The lineage distribution of M. tuberculosis showed that more than 3/4 of strains in Bogotá are commonly found in Latin America, Caribbean, and Europe. This observation might reflect the shared post-Columbus history of Colombia and its Latin-American neighbors as well as strains brought in by 20th century immigrants from Europe. We also demonstrate the usefulness of MIRU-VNTR to detect suspected links among patients and polyclonal infections.

Myxobolus sp., Another Opportunistic Parasite in Immunosuppressed Patients?

ABSTRACT During a study of intestinal parasitic infections in human immunodeficiency virus-positive patients, a parasite belonging to the phylum Myxozoa, recently described from human samples, was identified in one sample. When this parasite was stained by the modified Ziehl-Neelsen staining method, the features of the spores were identified: they were pyriform in shape, had thick walls, and had one suture and two polar capsules, with each one having four or five coils. The suture and two polar capsules were observed with the chromotrope-modified stain. The number of stools passed was more than 30 per day, but oocysts of Isospora belli were also found. Upon reexamination of some formalin- or merthiolate-iodine-formaldehyde-preserved samples an identical parasite was found in another sample from a patient presenting with diarrhea.Strongyloides stercoralis larvae and eggs ofHymenolepis nana and Ascaris lumbricoides were also found in this sample. Given that both patients were also infected with other pathogens that cause diarrhea, the possible pathogenic role of this parasite could not be established. The probable route of infection also could not be established.

Liver abscess caused by Ascaris lumbricoides: case report

A case is reported of a woman who lived in a rural area with a chronic illness that consisted of weight loss and abdominal pain in the epigastrium and upper right quadrant. The initial diagnosis was a mass in the liver, which was later, demonstrated, both by direct and histological examination, to be an abscess caused by Ascaris lumbricoides. Eggs of Ascaris lumbricoides and abundant Charcot-Leyden Crystals were found.

Virulence and Immune Response Induced by Mycobacterium avium Complex Strains in a Model of Progressive Pulmonary Tuberculosis and Subcutaneous Infection in BALB/c Mice

ABSTRACT The genus Mycobacterium comprises more than 150 species, including important pathogens for humans which cause major public health problems. The vast majority of efforts to understand the genus have been addressed in studies with Mycobacterium tuberculosis. The biological differentiation between M. tuberculosis and nontuberculous mycobacteria (NTM) is important because there are distinctions in the sources of infection, treatments, and the course of disease. Likewise, the importance of studying NTM is not only due to its clinical significance but also due to the mechanisms by which some species are pathogenic while others are not. Mycobacterium avium complex (MAC) is the most important group of NTM opportunistic pathogens, since it is the second largest medical complex in the genus after the M. tuberculosis complex. Here, we evaluated the virulence and immune response of M. avium subsp. avium and Mycobacterium colombiense, using experimental models of progressive pulmonary tuberculosis and subcutaneous infection in BALB/c mice. Mice infected intratracheally with a high dose of MAC strains showed high expression of tumor necrosis factor alpha (TNF-α) and inducible nitric oxide synthase with rapid bacillus elimination and numerous granulomas, but without lung consolidation during late infection in coexistence with high expression of anti-inflammatory cytokines. In contrast, subcutaneous infection showed high production of the proinflammatory cytokines TNF-α and gamma interferon with relatively low production of anti-inflammatory cytokines such as interleukin-10 (IL-10) or IL-4, which efficiently eliminate the bacilli but maintain extensive inflammation and fibrosis. Thus, MAC infection evokes different immune and inflammatory responses depending on the MAC species and affected tissue.

Complete Genome Sequence of the Clinical Beijing-Like Strain Mycobacterium tuberculosis 323 Using the PacBio Real-Time Sequencing Platform

ABSTRACT We report here the whole-genome sequence of the multidrug-resistant Beijing-like strain Mycobacterium tuberculosis 323, isolated from a 15-year-old female patient who died shortly after the initiation of second-line drug treatment. This strain is representative of the Beijing-like isolates from Colombia, where this lineage is becoming a public health concern.

Asociación Micobacterias-VIH/SIDA en Pacientes Atendidos en un Hospital Universitario en Bogotá, Colombia

Resumen es: Objetivo El objetivo del presente estudio fue evaluar la frecuencia de infecciones micobacterianas en pacientes infectados por el VIH y su repercusion e...

Genome Sequence of the Mycobacterium colombiense Type Strain, CECT 3035

We report the first whole-genome sequence of the Mycobacterium colombiense type strain, CECT 3035, which was initially isolated from Colombian HIV-positive patients and causes respiratory and disseminated infections. Preliminary comparative analyses indicate that the M. colombiense lineage has experienced a substantial genome expansion, possibly contributing to its distinct pathogenic capacity.

Epidemiología Molecular de la Tuberculosis en Bogotá en Aislados Clínicos obtenidos durante 11 Años

Objetivo Tipificar molecularmente aislados clinicos de Mycobacterium tuberculosis obtenidas en Bogota entre los anos 1995 a 2006, mediante la tecnica RFLP-IS6110 para establecer las relaciones filogeneticas existentes entre ellos y determinar casos debidos a infeccion reciente (casos agrupados) Vs reactivaciones endogenas (patrones unicos). Metodos Se realizo un estudio retrospectivo, en el que se incluyeron 137 aislados clinicos pertenecientes al complejo Mycobacterium tuberculosis, obtenidos en Bogota entre los anos 1995 a 2006. Las variables estudiadas para cada paciente fueron: sexo, edad, confeccion con el Virus de la Inmunodeficiencia Humana , habitante en situacion de calle, resultado de la baciloscopia, fecha del cultivo. Los aislados fueron identificados fenotipicamente y confirmados genotipicamente mediante el metodo molecular PRA y evaluados para sensibilidad a farmacos antituberculosos de primera linea utilizando el metodo simplificado de las proporciones multiples. La genotipificacion se realizo empleando el metodo de referencia RFLP-IS6110 (Polimorfismo en la Longitud de los Fragmentos de restriccion). Resultados Todos los aislados fueron confirmados como pertenecientes al complejo M. tuberculosis, mostrando la identificacion fenotipica una concordancia del 100 % con la identificacion genotipica. La monorresistencia encontrada fue de 9,4 %, y la MDR (resistencia a Rifampicina e Isoniazida) fue 2,9 %. La genotipificacion se realizo a 129 aislados, de los cuales 96 (74 %) mostraron diferentes patrones RFLP-IS6110 y 35 aislados (26 %) estuvieron agrupados en 17 clusters conformados por 2 a 4 aislados. La relacion epidemiologica entre los pacientes no pudo ser establecida en la mayoria de los casos. De las variables estudiadas solamente el estado de coinfeccion con VIH fue un predictor significativo para el agrupamiento (p<0.05). Conclusion Los resultados de nuestro estudio muestran un alto porcentaje de genotipos con patrones RFLP-IS6110 unicos, lo que sugiere gran variabilidad genetica entre los aislados de M. tuberculosis circulantes en Bogota, indicando que la mayoria de los casos de tuberculosis en el estudio pueden ser atribuibles a reactivaciones endogenas.

Deciphering the virulence factors of the opportunistic pathogen Mycobacterium colombiense

Mycobacterium avium complex (MAC) contains clinically important nontuberculous mycobacteria worldwide and is the second largest medical complex in the Mycobacterium genus after the Mycobacterium tuberculosis complex. MAC comprises several species that are closely phylogenetically related but diverse regarding their host preference, course of disease, virulence and immune response. In this study we provided immunologic and virulence-related insights into the M. colombiense genome as a model of an opportunistic pathogen in the MAC. By using bioinformatic tools we found that M. colombiense has deletions in the genes involved in p-HBA/PDIM/PGL, PLC, SL-1 and HspX production, and loss of the ESX-1 locus. This information not only sheds light on our understanding the virulence mechanisms used by opportunistic MAC pathogens but also has great potential for the designing of species-specific diagnostic tools.

Prevalencia y factores asociados a la tuberculosis y las micobacteriosis en pacientes positivos para HIV en Bogotá

INTRODUCTION Tuberculosis is one of the most widely distributed infectious diseases worldwide. It is the most common cause of mortality among AIDS patients. In Colombia, 12,918 tuberculosis cases were notified, and 926 deaths were reported in 2015. OBJECTIVE To determine the prevalence and risk factors associated to mycobacterial infections in HIVpositive patients in two public hospitals from Bogotá. MATERIALS AND METHODS A prospective and descriptive study was carried out by an active search for tuberculosis cases and non-tuberculous mycobacterial infections in HIV-positive patients. We considered demographic, social, clinical, and personal habits as variables. Statistical analyses were done using Stata 13™ software. RESULTS Three hundred and fifty six patients were included, 81.2% were men and 18.8% were women; the mean age was 36.5 years. Tuberculosis infection had a frequency of 19.9% (95% CI: 15.9-24.5%) and non-tuberculous mycobacterial infection had a 3.9% frequency (95% CI: 2.16-6.5%). Bivariate analysis showed a statistically significant association between tuberculosis infection and CD4+ T cell counts (p=0.003), viral load (p=0.008), antiretroviral therapy (p=0.014), and body mass index (BMI) <18 kg/m2 (p=0.000). In non-tuberculous mycobacterial infections there was a statistically significantassociation with BMI (p=0.027) and CD4+ T cell counts (p=0.045). CONCLUSION Factors associated with an impaired immune system caused by HIV infection are an important risk factor for developing tuberculosis. The lack of antiretroviral therapy and the BMI were also important risk factors for tuberculosis.