Genotypic diversity of Mycobacterium tuberculosis in Buenos Aires, Argentina.

Buenos Aires is an overpopulated port city historically inhabited by people of European descent. Together with its broader metropolitan area, the city exhibits medium tuberculosis rates, and receives migrants, mainly from tuberculosis highly endemic areas of Argentina and neighboring countries. This work was aimed to gain insight into the Mycobacterium tuberculosis population structure in two suburban districts of Buenos Aires which are illustrative of the overall situation of tuberculosis in Argentina. The Lineage 4 Euro-American accounted for >99% of the 816 isolates analyzed (one per patient). Frequencies of spoligotype families were T 35.9%, LAM 33.2%, Haarlem 19.5%, S 3.2%, X 1.5%, Ural 0.7%, BOV 0.2%, Beijing 0.2%, and Cameroon 0.2%. Unknown signatures accounted for 5.3% isolates. Of 55 spoligotypes not matching any extant shared international type (SIT) in SITVIT database, 22 fitted into 15 newly-issued SITs. Certain autochthonous South American genotypes were found to be actively evolving. LAM3, which is wild type for RDrio, was the predominant LAM subfamily in both districts and the RDrio signature was rare among autochthonous, newly created, SITs and orphan patterns. Two genotypes that are rarely observed in neighboring countries ̶ SIT2/H2 and SIT159/T1 Tuscany ̶ were conspicuously represented in Argentina. The infrequent Beijing patterns belonged to Peruvian patients. We conclude that the genotype diversity observed reflects the influence of the Hispanic colonization and more recent immigration waves from Mediterranean and neighboring countries. Unlike in Brazil, the RDrio type does not play a major role in the tuberculosis epidemic in Buenos Aires.

[Distribution of PRA patterns of clinical isolates of the Mycobacterium avium complex from Spain and South America]. / Distribución de patrones PRA en aislamientos clínicos del complejo Mycobacterium avium procedentes de España y Suramérica.

Mycobacterium avium complex (MAC) infections are the most frequent systemic infections associated with advanced AIDS. DNA probes for accurate identification of mycobacteria are available but are very expensive in many Latin American settings. Consequently, most Latin American diagnostic laboratories employ inaccurate and outdated tests for mycobacteria identification. Therefore, PCR restriction analysis (PRA) of the hsp65 gene was evaluated for the identification of 163 MAC human isolates originated from Spain and South America. The predominant PRA type in each country was: M. avium type I in Argentina (23/42, 55%) and Brazil (48/72, 67%), M. avium type II in Spain (18/26, 69%) and M. avium type III in Colombia (10/23, 43%). The Colombia frequency is noteworthy, since the PRA type III was quite infrequent in the other three countries. Furthermore, its presence has not been reported outside the Americas. The advantages and disadvantages of PRA in diagnostic mycobacteriology are discussed.

Distribución de patrones PRA en aislamientos clínicos del complejo Mycobacterium avium procedentes de España y Suramérica

La infección por el complejo Mycobacterium avium (MAC) es la infección sistémica más frecuente en la fase terminal del SIDA. Las sondas de ADN disponibles en el mercado para la identificación de micobacterias son muy precisas pero extremadamente costosas. Por eso, la mayoría de los laboratorios clínicos de Latinoamérica aún tipifican micobacterias mediante pruebas fenotípicas que son lentas, laboriosas y poco precisas. En este trabajo se aplicó el análisis del polimorfismo de los fragmentos de restricción del gen hsp65 (PRA) a la identificación de MAC en 163 aislamientos clínicos procedentes de España y Suramérica. El genotipo PRA predominante en cada país fue: M. avium tipo I en Argentina (23/42, 55%) y Brasil (48/72, 67%), M. avium tipo II en España (18/26, 69%) y M. avium tipo III en Colombia (10/23, 43%). Este último genotipo, que aún no fue descrito fuera del continente americano, resultó muy infrecuente en los otros tres países del estudio. Se discuten ventajas e inconvenientes de la aplicación del PRA al diagnóstico micobacteriológico.

Distribution of PRA patterns of clinical isolates of the Mycobacterium avium complex from Spain and South America Mycobacterium avium complex (MAC) infections are the most frequent systemic infections associated with advanced AIDS. DNA probes for accurate identification of mycobacteria are available but are very expensive in many Latin American settings. Consequently, most Latin American diagnostic laboratories employ inaccurate and outdated tests for mycobacteria identification. Therefore, PCR restriction analysis (PRA) of the hsp65 gene was evaluated for the identification of 163 MAC human isolates originated from Spain and South America. The predominant PRA type in each country was: M. avium type I in Argentina (23/42, 55%) and Brazil (48/72, 67%), M. avium type II in Spain (18/26, 69%) and M. avium type III in Colombia (10/ 23, 43%). The Colombia frequency is noteworthy, since the PRA type III was quite infrequent in the other three countries. Furthermore, its presence has not been reported outside the Americas. The advantages and disadvantages of PRA in diagnostic mycobacteriology are discussed.

Multidrug resistant tuberculosis outbreak in Buenos Aires: DNA fingerprinting analysis of isolates

In order to determine the possible relationship among HIV patients coinfected with multidrug resistant tuberculosis strains who had been receiving clinical assistance in our Hospital, clinical and epidemiological information from 28 patients was collected. DNA fingerprinting by restriction fragment length polymorphism (RFLP) pattern was performed on the mycobacterial isolates from these patients, using the restriction enzyme Pvull and IS 6110 as genetic marker. A unique RFLP pattern was found in 10 isolates from 10 different patients who had a disease caused by a single strain. Our findings confirm RFLP as a reliable and useful tool to analyze TB transmission.

Hospital transmission of multidrug-resistant Mycobacterium tuberculosis in Rosario, Argentina

Multidrug-resistant tuberculosis has emerged over the last two years at Carrasco Hospital, located in Rosario city. Nosocomial transmission among 7 AIDS patients admitted into the same ward between June and December/94 was supported by temporal clustering of cases, matching drug susceptibility, and identical lS6llO fingerprints. Among 8 non-HIV chronic cases without evidence of reciprocal contact outside the hospital, two additional clusters of 2 and 4 cases, respectively, were identified. The latter was found to be generated by a strain genetically related to the one that infected AIDS patients. lt is hypothesized that an ancestor strain, common to both, might have been brought into the hospital long before the outbreak was first suspected.

Multidrug resistant tuberculosis outbreak in Buenos Aires: DNA fingerprinting analysis of isolates

In order to determine the possible relationship among HIV patients coinfected with multidrug resistant tuberculosis strains who had been receiving clinical assistance in our Hospital, clinical and epidemiological information from 28 patients was collected. DNA fingerprinting by restriction fragment length polymorphism (RFLP) pattern was performed on the mycobacterial isolates from these patients, using the restriction enzyme Pvull and IS 6110 as genetic marker. A unique RFLP pattern was found in 10 isolates from 10 different patients who had a disease caused by a single strain. Our findings confirm RFLP as a reliable and useful tool to analyze TB transmission. (AU)

Hospital transmission of multidrug-resistant Mycobacterium tuberculosis in Rosario, Argentina

Multidrug-resistant tuberculosis has emerged over the last two years at Carrasco Hospital, located in Rosario city. Nosocomial transmission among 7 AIDS patients admitted into the same ward between June and December/94 was supported by temporal clustering of cases, matching drug susceptibility, and identical lS6llO fingerprints. Among 8 non-HIV chronic cases without evidence of reciprocal contact outside the hospital, two additional clusters of 2 and 4 cases, respectively, were identified. The latter was found to be generated by a strain genetically related to the one that infected AIDS patients. lt is hypothesized that an ancestor strain, common to both, might have been brought into the hospital long before the outbreak was first suspected. (AU)

Infecciones hospitalarias por tuberculosis multirresistente en grandes urbes del país: caracterización genómica de los aislamientos / Hospitalary infections by multiresistant tuberculosis in great cities of the country: genomic characterization of the isolations

El Hospital Muñiz, de la cdad. de Buenos Aires y el Policlínico Carrasco de Rosario, son centros de salud de referencia y concentran pacientes tuberculosos crónicos, así como casos de infecciones severas asociadas con SIDA. En ambos hospitales se observó, a partir de mediados de 1994, un notable incremento en el número de aislamientos M.tuberculosis con resistencia a múltiples drogas. El patrón común de resistencia observado en un alto porcentaje de aislamientos, sumado a la predominancia de casos asociados al SIDA, procedentes de un mismo pabellón o sala indujeron la sospecha de transmisión hospitalaria de la infección en ambos nosocomios. Con el objeto de verificar dicha sospecha, se determinó -mediante fingerprinting del ADN con IS6110- la identidad genética de 153 aislamientos multirresistentes de M.tuberculosis procedentes de 116 casos ocurridos en el Hospital Muñiz entre 1992 y 1995, 11 pacientes internados en 5 hospitales del conurbano bonaerense durante el mismo período, con presunta vinculación epidemiológica con casos del Hospital Muñiz, y 26 casos del policlínico carrasco de Rosario. De los 127 aislamientos procedentes de Buenos Aires y su área conurbana, 75 presentaron idéntico fingerprinting, 69 de los cuales correspondían a casos de SIDA del Hospital Muñiz [edad media 30 años, mortalidad 85 por ciento]. Cinco variantes de esta cepa con diferencias mínimas con respecto al patrón común fueron identificadas en los aislamientos de otros 8 casos procedentes de dos hospitales. Los aislamientos de otros 9 pacientes procedentes de 3 hospitales presentaron homología total entre sí, con un patrón genómico diferente al anterior, pero a su vez idéntico al de un brote ocurrido en el Hospital Cetrángolo. En el Policlínico Carrasco de Rosario, se documentó trasmisión hospitalaria en 24 de los 26 casos estudiados. Una de las tres cepas involucradas en el brote se diseminó en dos salas entre 5 pacientes sin factores de riesgo para HIV y 3 casos de SIDA. Otra, emparentada genéticamente con la anterior, afectó a 14 pacientes con SIDA internados en la misma sala. Se postula que un ancestro común a ambas pudo haber sido introducido en el hospital años antes de que surgiera la sospecha de un brote... (TRUNCADO)

Infecciones hospitalarias por tuberculosis multirresistente en grandes urbes del país: caracterización genómica de los aislamientos / Hospitalary infections by multiresistant tuberculosis in great cities of the country: genomic characterization of the isolations

El Hospital Muñiz, de la cdad. de Buenos Aires y el Policlínico Carrasco de Rosario, son centros de salud de referencia y concentran pacientes tuberculosos crónicos, así como casos de infecciones severas asociadas con SIDA. En ambos hospitales se observó, a partir de mediados de 1994, un notable incremento en el número de aislamientos M.tuberculosis con resistencia a múltiples drogas. El patrón común de resistencia observado en un alto porcentaje de aislamientos, sumado a la predominancia de casos asociados al SIDA, procedentes de un mismo pabellón o sala indujeron la sospecha de transmisión hospitalaria de la infección en ambos nosocomios. Con el objeto de verificar dicha sospecha, se determinó -mediante fingerprinting del ADN con IS6110- la identidad genética de 153 aislamientos multirresistentes de M.tuberculosis procedentes de 116 casos ocurridos en el Hospital Muñiz entre 1992 y 1995, 11 pacientes internados en 5 hospitales del conurbano bonaerense durante el mismo período, con presunta vinculación epidemiológica con casos del Hospital Muñiz, y 26 casos del policlínico carrasco de Rosario. De los 127 aislamientos procedentes de Buenos Aires y su área conurbana, 75 presentaron idéntico fingerprinting, 69 de los cuales correspondían a casos de SIDA del Hospital Muñiz [edad media 30 años, mortalidad 85 por ciento]. Cinco variantes de esta cepa con diferencias mínimas con respecto al patrón común fueron identificadas en los aislamientos de otros 8 casos procedentes de dos hospitales. Los aislamientos de otros 9 pacientes procedentes de 3 hospitales presentaron homología total entre sí, con un patrón genómico diferente al anterior, pero a su vez idéntico al de un brote ocurrido en el Hospital Cetrángolo. En el Policlínico Carrasco de Rosario, se documentó trasmisión hospitalaria en 24 de los 26 casos estudiados. Una de las tres cepas involucradas en el brote se diseminó en dos salas entre 5 pacientes sin factores de riesgo para HIV y 3 casos de SIDA. Otra, emparentada genéticamente con la anterior, afectó a 14 pacientes con SIDA internados en la misma sala. Se postula que un ancestro común a ambas pudo haber sido introducido en el hospital años antes de que surgiera la sospecha de un brote... (TRUNCADO)(AU)