Description of a novel adhesin of Mycobacterium avium subsp. paratuberculosis.

The binding and ingestion of Mycobacterium avium subsp. paratuberculosis (MAP) by host cells are fibronectin (FN) dependent. In several species of mycobacteria, a specific family of proteins allows the attachment and internalization of these bacteria by epithelial cells through interaction with FN. Thus, the identification of adhesion molecules is essential to understand the pathogenesis of MAP. The aim of this study was to identify and characterize FN binding cell wall proteins of MAP. We searched for conserved adhesins within a large panel of surface immunogenic proteins of MAP and investigated a possible interaction with FN. For this purpose, a cell wall protein fraction was obtained and resolved by 2D electrophoresis. The immunoreactive spots were identified by MALDI-TOF MS and a homology search was performed. We selected elongation factor Tu (EF-Tu) as candidate for further studies. We demonstrated the FN-binding capability of EF-Tu using a ligand blot assay and also confirmed the interaction with FN in a dose-dependent manner by ELISA. The dissociation constant of EF-Tu was determined by surface plasmon resonance and displayed values within the µM range. These data support the hypothesis that this protein could be involved in the interaction of MAP with epithelial cells through FN binding.

Characterization of a Mycobacterium avium subsp. avium operon associated with virulence and drug detoxification.

The lprG-p55 operon of Mycobacterium tuberculosis and Mycobacterium bovis is involved in the transport of toxic compounds. P55 is an efflux pump that provides resistance to several drugs, while LprG is a lipoprotein that modulates the host's immune response against mycobacteria. The knockout mutation of this operon severely reduces the replication of both mycobacterial species during infection in mice and increases susceptibility to toxic compounds. In order to gain insight into the function of LprG in the Mycobacterium avium complex, in this study, we assayed the effect of the deletion of lprG gene in the D4ER strain of Mycobacterium avium subsp. avium. The replacement of lprG gene with a hygromycin cassette caused a polar effect on the expression of p55. Also, a twofold decrease in ethidium bromide susceptibility was observed and the resistance to the antibiotics rifampicin, amikacin, linezolid, and rifabutin was impaired in the mutant strain. In addition, the mutation decreased the virulence of the bacteria in macrophages in vitro and in a mice model in vivo. These findings clearly indicate that functional LprG and P55 are necessary for the correct transport of toxic compounds and for the survival of MAA in vitro and in vivo.

Difference in virulence of Mycobacterium avium isolates sharing indistinguishable DNA fingerprint determined in murine model of lung infection.

BACKGROUND: Opportunistic Mycobacterium avium typically causes disease in immunocompromised patients and in some groups of apparently healthy individuals. The high virulence of some bacterial lineages increases the disease risk. High-resolution molecular genotyping studies of M. avium clinical isolates demonstrated that some genotype patterns were more prevalent than others, suggesting that close genetic relatedness of these successful isolates sharing a similar genotype could determine similar biological properties associated with high virulence. METHODS AND FINDINGS: In this study, we aimed to compare the virulence and pathogenic properties of two epidemiologically unrelated M. avium isolates sharing an indistinguishable DNA fingerprint in a well-characterized model of pulmonary infection in mice, resistant or susceptible to mycobacteria. The mice, C57BL/6 wild- type or IFN-gamma gene disrupted (GKO), respectively, were intratracheally infected with two isolates, H27 (human blood isolate) and P104 (pig lymph node isolate), and the lungs were examined for bacterial loads, histopathology and cytokine gene expression. The obtained data demonstrated significant differences in the virulence properties of these strains. Although the H27 strain grew significantly faster than P104 in the early stage of infection, this bacterium induced protective immunity that started to reduce bacterial numbers in the wild-type mice, whereas the P104 strain established a chronic infection. In the GKO mice, both strains were capable of causing a chronic infection, associated with higher bacterial burdens and severe lung pathology, in a similar manner. CONCLUSIONS/SIGNIFICANCE: The results demonstrated that the studied isolates differed in the pathogenic properties although were indistinguishable by actually widely used genotyping techniques demonstrating that the genotype similarity does not predict similarity in virulence of M. avium isolates.

Levantamento sorológico de Mycobacterium avium subesp. paratuberculosis em bovinos leiteiros no estado do Espírito Santo / Serological survey of Mycobacterium avium subsp. paratuberculosis in dairy cattle in Espírito Santo state

The occurrence of antibodies to Mycobacterium avium subsp. paratuberculosis (MAP) was verified in dairy cattle from Espírito Santo state. A total of 1,450 serum samples were analyzed for antibodies anti-MAP, using ELISA. Dairy cattle, males and females, from four regions of Espírito Santo state were used. One hundred sixty-five (11.4 percent) samples were positive for anti-MAP, 33 (2.3 percent) were considered suspicious, and 1,252 (86.3 percent) were negative. In all regions, seropositive animals were found, indicating that the agent is spread by the State, posing a threat to the local dairy farming and neighboring states, as well as public health, since MAP can be involved with Crohn's disease in humans. This result presents the first serologic anti-MAP survey in dairy cattle of Espírito Santo State.(AU)

Levantamento sorológico de Mycobacterium avium subesp. paratuberculosis em bovinos leiteiros no estado do Espírito Santo / Serological survey of Mycobacterium avium subsp. paratuberculosis in dairy cattle in Espírito Santo state

The occurrence of antibodies to Mycobacterium avium subsp. paratuberculosis (MAP) was verified in dairy cattle from Espírito Santo state. A total of 1,450 serum samples were analyzed for antibodies anti-MAP, using ELISA. Dairy cattle, males and females, from four regions of Espírito Santo state were used. One hundred sixty-five (11.4 percent) samples were positive for anti-MAP, 33 (2.3 percent) were considered suspicious, and 1,252 (86.3 percent) were negative. In all regions, seropositive animals were found, indicating that the agent is spread by the State, posing a threat to the local dairy farming and neighboring states, as well as public health, since MAP can be involved with Crohn's disease in humans. This result presents the first serologic anti-MAP survey in dairy cattle of Espírito Santo State.

Comentarios clínicos acerca de las micobacteriosis pulmonares / Pulmonary mycobacterioses: clinical commentaries

Las micobacteriosis pulmonares son afecciones provocadas por micobacterias ambientales, de evolución crónica y clínicamente similares a la tuberculosis. Se analiza una serie de 26 casos asistidos en el Hospital Muñiz de la Ciudad de Buenos Aires, con una edad promedio de 59.2 años, 73.1% de sexo femenino y 80.1% de los casos de nivel socioeconómico mediano a alto. Se hallaron enfermedades predisponentes en el 88.5% de los casos (tuberculosis previa, EPOC, silicosis, reflujo gastroesofágico). Desde el punto de vista radiológico se observaron nódulos, bronquiectasias y cavidades pequeñas en 14 casos y lesiones bilaterales cavitarias extensas en 12. Se destacó la mayor frecuencia de Mycobacterium avium complex como patógeno, la mejor evolución de los pacientes con menor compromiso pulmonar y la de los afectados por M. avium en relación con otras micobacterias. Los fármacos más utilizados en el tratamiento fueron claritromicina y azitromicina, asociados a etambutol. La proporción global de curaciones fue baja (57.7%) pero superior en los casos provocados por M. avium (86.7%).(AU)

Comentarios clínicos acerca de las micobacteriosis pulmonares / Pulmonary mycobacterioses: clinical commentaries

Las micobacteriosis pulmonares son afecciones provocadas por micobacterias ambientales, de evolución crónica y clínicamente similares a la tuberculosis. Se analiza una serie de 26 casos asistidos en el Hospital Muñiz de la Ciudad de Buenos Aires, con una edad promedio de 59.2 años, 73.1% de sexo femenino y 80.1% de los casos de nivel socioeconómico mediano a alto. Se hallaron enfermedades predisponentes en el 88.5% de los casos (tuberculosis previa, EPOC, silicosis, reflujo gastroesofágico). Desde el punto de vista radiológico se observaron nódulos, bronquiectasias y cavidades pequeñas en 14 casos y lesiones bilaterales cavitarias extensas en 12. Se destacó la mayor frecuencia de Mycobacterium avium complex como patógeno, la mejor evolución de los pacientes con menor compromiso pulmonar y la de los afectados por M. avium en relación con otras micobacterias. Los fármacos más utilizados en el tratamiento fueron claritromicina y azitromicina, asociados a etambutol. La proporción global de curaciones fue baja (57.7%) pero superior en los casos provocados por M. avium (86.7%).

Ocorrência de paratuberculose em búfalos (Bubalus bubalis) em Pernambuco / Occurrence of paratuberculosis in buffaloes (Bubalus bubalis) in Pernambuco

A paratuberculose (doença de Johne) é uma das doenças de maior importância econômica para ruminantes em vários países e pode representar uma ameaça ao desenvolvimento da pecuária brasileira. É uma doença infecto-contagiosa que provoca enterocolite granulomatosa crônica, incurável e de difícil controle, cujo agente é o Mycobacterium avium subsp. paratuberculosis (MAP). Descreve-se a ocorrência de paratuberculose em um rebanho de búfalos no Estado de Pernambuco, Brasil. Não foi encontrado registro, na literatura, da ocorrência de paratuberculose em búfalos no país. De 100 búfalos, cinco mostravam sinais clínicos característicos da doença. À necropsia de dois animais as lesões estavam restritas ao intestino delgado com evidente espessamento da mucosa, aumento de linfonodos mesentéricos e vasos linfáticos proeminentes e dilatados. À microscopia, observaram-se na mucosa do intestino, infiltrado inflamatório granulomatoso com numerosos macrófagos epitelióides e células gigantes de Langhans, além de bacilos álcool-ácido resistentes (BAAR) visualizados através da coloração de Ziehl-Neelsen (ZN). Nos linfonodos mesentéricos, havia espessamento da cápsula e marcada inflamação granulomatosa. O exame direto pela técnica de ZN para pesquisa do bacilo em esfregaços de fezes, raspado de mucosa intestinal e imprint de linfonodos mesentéricos resultou positivo. A PCR IS900 específico de linfonodo mesentérico e mucosa intestinal revelou amplificação de um fragmento de aproximadamente 110pb, confirmada pela comparação com outras sequências de M. avium subsp. paratuberculosis disponíveis no GenBank.(AU)

Paratuberculosis (PTB) is a disease of great economical importance for ruminant in several countries and represents a threat to the development of Brazilian livestock. The contagious disease caused by chronic PTB leads to incurable granulomatous enterocolitis of difficult control. PTB is caused by the Mycobacterium avium subsp. paratuberculosis (MAP). No record on the occurrence of paratuberculosis in buffaloes in Brazil could be found. Five of 100 buffaloes in a herd in Pernambuco-Brazil showed clinical signs characteristic of PTB. At necropsy, of two animals the lesions were restricted to the small intestine with thickening and corrugation of the mucosa, increase of mesenteric lymph nodes and prominent lymph vessels. Histopathology revealed granulomatous inflammation infiltrated with numerous epithelioid macrophages, Langhans type giant cells, and clusters of Ziehl-Neelsen (ZN) positive organisms within the intestinal mucosa. In the mesenteric lymph nodes there was thickening of the capsule and marked granulomatous inflammation. Smears of feces and scrapping smears were prepared from intestinal mucosa and cut surface of mesenteric lymph nodes and, stained by the Ziehl-Neelsen method for research of acid fast bacilli, with positive results. Lymph nodes and intestinal mucosa revealed at IS900 specific polymerase chain reaction amplification of a fragment of about 110pb, confirmed by the comparison with other sequences of M. avium subsp. paratuberculosis available in GenBank.(AU)

Ocorrência de paratuberculose em búfalos (Bubalus bubalis) em Pernambuco / Occurrence of paratuberculosis in buffaloes (Bubalus bubalis) in Pernambuco

A paratuberculose (doença de Johne) é uma das doenças de maior importância econômica para ruminantes em vários países e pode representar uma ameaça ao desenvolvimento da pecuária brasileira. É uma doença infecto-contagiosa que provoca enterocolite granulomatosa crônica, incurável e de difícil controle, cujo agente é o Mycobacterium avium subsp. paratuberculosis (MAP). Descreve-se a ocorrência de paratuberculose em um rebanho de búfalos no Estado de Pernambuco, Brasil. Não foi encontrado registro, na literatura, da ocorrência de paratuberculose em búfalos no país. De 100 búfalos, cinco mostravam sinais clínicos característicos da doença. À necropsia de dois animais as lesões estavam restritas ao intestino delgado com evidente espessamento da mucosa, aumento de linfonodos mesentéricos e vasos linfáticos proeminentes e dilatados. À microscopia, observaram-se na mucosa do intestino, infiltrado inflamatório granulomatoso com numerosos macrófagos epitelióides e células gigantes de Langhans, além de bacilos álcool-ácido resistentes (BAAR) visualizados através da coloração de Ziehl-Neelsen (ZN). Nos linfonodos mesentéricos, havia espessamento da cápsula e marcada inflamação granulomatosa. O exame direto pela técnica de ZN para pesquisa do bacilo em esfregaços de fezes, raspado de mucosa intestinal e imprint de linfonodos mesentéricos resultou positivo. A PCR IS900 específico de linfonodo mesentérico e mucosa intestinal revelou amplificação de um fragmento de aproximadamente 110pb, confirmada pela comparação com outras sequências de M. avium subsp. paratuberculosis disponíveis no GenBank.

Paratuberculosis (PTB) is a disease of great economical importance for ruminant in several countries and represents a threat to the development of Brazilian livestock. The contagious disease caused by chronic PTB leads to incurable granulomatous enterocolitis of difficult control. PTB is caused by the Mycobacterium avium subsp. paratuberculosis (MAP). No record on the occurrence of paratuberculosis in buffaloes in Brazil could be found. Five of 100 buffaloes in a herd in Pernambuco-Brazil showed clinical signs characteristic of PTB. At necropsy, of two animals the lesions were restricted to the small intestine with thickening and corrugation of the mucosa, increase of mesenteric lymph nodes and prominent lymph vessels. Histopathology revealed granulomatous inflammation infiltrated with numerous epithelioid macrophages, Langhans type giant cells, and clusters of Ziehl-Neelsen (ZN) positive organisms within the intestinal mucosa. In the mesenteric lymph nodes there was thickening of the capsule and marked granulomatous inflammation. Smears of feces and scrapping smears were prepared from intestinal mucosa and cut surface of mesenteric lymph nodes and, stained by the Ziehl-Neelsen method for research of acid fast bacilli, with positive results. Lymph nodes and intestinal mucosa revealed at IS900 specific polymerase chain reaction amplification of a fragment of about 110pb, confirmed by the comparison with other sequences of M. avium subsp. paratuberculosis available in GenBank.

Identification of proteins from tuberculin purified protein derivative (PPD) by LC-MS/MS.

The tuberculin purified protein derivative (PPD) is a widely used diagnostic antigen for tuberculosis, however it is poorly defined. Most mycobacterial proteins are extensively denatured by the procedure employed in its preparation, which explains previous difficulties in identifying constituents from PPD to characterize their behaviour in B- and T-cell reactions. We here described a proteomics-based characterization of PPD from several different sources by LC-MS/MS, which combines the solute separation power of HPLC, with the detection power of a mass spectrometer. The technique is able to identify proteins from complex mixtures of peptide fragments. A total of 171 different proteins were identified among the four PPD samples (two bovine PPD and two avium PPD) from Brazil and UK. The majority of the proteins were cytoplasmic (77.9%) and involved in intermediary metabolism and respiration (24.25%) but there was a preponderance of proteins involved in lipid metabolism. We identified a group of 21 proteins that are present in both bovine PPD but were not detected in avium PPD preparation. In addition, four proteins found in bovine PPD are absent in Mycobacterium bovis BCG vaccine strain. This study provides a better understanding of the tuberculin PPD components leading to the identification of additional antigens useful as reagents for specific diagnosis of tuberculosis.

Identification of non-tuberculous mycobacteria from the Central Public Health Laboratory from Mato Grosso do Sul and analysis of clinical relevance / Identificação de micobactérias não-tuberculosas do Laboratório Central de Saúde Pública de Mato Grosso de Sul e análise de dados clínicos dos pacientes

Non-tuberculous mycobacteria isolated at the Central Public Health Laboratory from Mato Grosso do Sul in 2003 and 2004 were identified by conventional phenotypic methods (TI) and by PCR-Restriction Enzyme Analysis (PRA) using the hsp65 gene as target (PRA-hsp65). With 15 of the 32 analysed isolates, results of both methods were concordant, being 8 Mycobacterium avium, 3 M. fortutium, 1 M. kansasii, 1 M. flavescens, 1 M. peregrinum and 1 Nocardia brasiliensis. TI of 12 isolates was inconclusive. Novel PRA-hsp65 patterns were observed with 11 isolates. Medical data were evaluated for inference of clinical relevance of these isolates.

Micobactérias não-tuberculosas isoladas no Laboratório Central de Saúde Pública de Mato Grosso do Sul em 2003 e 2004 foram identificadas usando métodos fenotípicos convencionais (TI) e PCR-Restriction Enzyme Analysis (PRA) tendo o gene hsp65 como alvo (PRA-hsp65). Em 15 dos 32 isolados analisados os resultados obtidos com ambos métodos foram concordantes, sendo 8 Mycobacterium avium, 3 M. fortutium, 1 M. kansasii, 1 M. flavescens, 1 M. peregrinum e 1 Nocardia brasiliensis. TI de 12 isolados não foi conclusiva. Perfis não descritos de PRA-hsp65 foram observados com 11 isolados. Dados dos prontuários médicos foram avaliados para inferir a relevância clínica dos isolados.

Similaridades clinicopatológicas entre paratuberculosis y enfermedad de crohn: ¿posible vínculo zoonótico? / Clinical and pathological similarities between paratuberculosis and crohn’s disease: ¿a possible zoonotic link?

EL artículo presenta a la luz de la literatura científica actual la asociación del Mycobacterium avium subespecie paratuberculosis con la enfermedad de Crohn, las principales similaridades clinicopatológicas. La revisión se limitó a las publicaciones contenidas en el programa HINARI de la WHO, en especial de Elservier Science, Bioline Internacional, Blackwell Publishing, BMJ Publishing, Lippincott Williams & Wilkins, Nature Publishing, PubMed, Springer Science y publicaciones de la Asociación Internacional para estudio de Paratuberculosis. Evidencias significativas apoyan un posible vinculo zoonótico entre las enfermedades. El aislamiento del Mycobacterium avium subespecie paratuberculosis en pacientes con enfermedad de Crohn desde muestras de intestino, leche, sangre periférica y nódulos linfáticos; de igual manera la respuesta inmune especifica a algunos antígenos de Mycobacterium en pacientes con la enfermedad; aunque estos hallazgos tienen cada uno sus propias controversias. La evidencia actualmente disponible no es suficiente para validar o negar al Mycobacterium avium subespecie paratuberculosis como agente causal de por lo menos algunos casos de enfermedad de Crohn. Los estudios son inconclusos en aceptar un vinculo zoonótico dada la naturaleza multifactorial de esta enfermedad. Se requieren estudios para determinar sí Mycobacterium es un agente espectador ó patogénico; paralelamente realizar estudios epidemiológicos a gran escala que permitan analizar la distribución geográfica y temporal de ambas enfermedades.

Adesäo de Mycobacterium tuberculosis, M. avium e de M. fortuitum em células McCoy / Adherence capacity of M. tuberculosis, M. avium and M. fortuitum on McCoy cells line

A capacidade de adesäo do M. tuberculosis, M. avium e M. fortuitum às células da linhagem McCoy foi analisada, em intervalos de tempo predeterminados. Foram estabalecidas para o ensaio concentraçäo de 10(5) células/ml de meio de Eagle, suspensäo inoculante das micobactérias na fase logarítima e incubaçäo sob agitaçäo de 60 rpm para se evitar adesäo inespecífica. Verificou-se adesäo mais rápida e eficiente do M. fortuitum às células McCoy em relaçäo às outras duas micobactérias

Mycobacterium avium infection and AIDS: a therapeutic dilemma in rapid evolution

Note from Dr. Merle A. Sande - The role of Mycobacterium avium as a pathogen in the human immunodeficiency virus-infected population has been confusing and controversial to clinicians who care for AIDS patients. The organisms is commonly isolated from respiratory secretions of patients with other infections and often seems part of the resident flora; even when isolated from the bone marrow or bloodstream, its impact on the course of AIDS and contribution to systemic diseases are unknown. However, an increasing subset of patients without other documented opportunistic infections or malignancies has symptoms that respond to therapy directed againts M. avium. Studies are in progress to evaluate chemotherapeutic agents. Accordingly, the subject is here reviewed and guidelines offered to infectious disease clinicians by one with a long-standing interest in mycobacterial diseasewho has made numerous contributions to the field

Phagocytosis and intracellular killing of Mycobacterium avium complex by human and murine macrophages.

1. Host defenses against Mycobacterium avium complex (MAC) are poorly defined. Peritoneal macrophages from black and beige mice, and cultured human macrophages were infected in vitro with MAC serotype 1 from an AIDS patient, in the presence or absence of normal or convalescent serum. Bacteria:cell ratio was 1:10. Supernatants and macrophage lysates were cultured 6, 24 and 48 h later to determine the uptake and killing by macrophages. Phagocytosis by activated macrophages, obtained from pre-infected and treated mice or stimulated in vitro with endotoxin, was also studied. 2. Neither convalescent serum nor normal serum caused a significant increase in MAC phagocytosis. 3. Unstimulated macrophages from black or beige mice and humans were incapable of killing the intracellular bacteria. Activated macrophages from all sources phagocytized and killed 80 +/- 4% of the initial inoculum after 48 h in culture. 4. These results demonstrate that activated macrophages are required for optimal intracellular killing of serotype 1 MAC.

Anonymous mycobacteria in pulmonary disease / ?

1- The guinea pig test is insufficient to indicate the pathogenic potential of strains of acid-fast bacteria, no tubercle bacilli, in clinical specimens. Mouse susceptibility and other information is required. 2- Clinical, radiologic and histologic studies are as yet insufficient to differentiate pulmonary diseases due to various distinct types of anonymous ("atypical") acid-fast organisms from each other and from tuberculosis. Bacteriologic identification is required. 3- Four groups of these anonymous strains occur sporadically or commonly, and these can be distinguished from tubercle bacilli by drug resistance, catalase activity, capacity to grow at room temperature,etc...