Biomarcadores en tuberculosis / Biomarkers in tuberculosis

Resumen Los métodos diagnósticos clásicos para la tuberculosis son de baja sensibilidad o son muy lentos en la obtención de resultados (baciloscopía, cultivo de Koch). De ahí nace la necesidad de nuevos métodos diagnósticos para esta enfermedad. Los biomarcadores surgen como una opción a esta problemática, con un buen rendimiento diagnóstico, costo y accesibilidad. Ellos permiten identificar la respuesta inflamatoria y/o metabólica del huésped, extrapolando la presencia de Mycobacterium tuberculosis; o identifican moléculas propias del patógeno. En la presente revisión se describen biomarcadores que presentan un buen rendimiento diagnóstico basados en metodologías de investigación de alto nivel (estudio de cohortes, prospectivos, muestreo consecutivo o aleatorizado, comparación de rendimiento diagnóstico frente a cultivo). Es necesario el desarrollo de estas nuevas técnicas con el fin de realizar el diagnóstico precoz de la enfermedad y lograr así su tan ansiada eliminación.

The classical laboratory diagnostic methods for tuberculosis have a low sensitivity or take a long time to know their results. New methods are underway. Biomarkers are a good option to improve our diagnostic approach to this disease. They have good performance, low cost and accessibility. They identify a patient's inflammatory or metabolic response to Mycobacterium Tuberculosis or identifies molecules that are typical of the pathogen. In this paper we sum up the biomarkers with a good diag-nostic performance described in well design investigations. Early diagnosis with these new techniques should contribute to the elimination of the disease.

Lung Infection Caused by Mycobacterium riyadhense Confused with Mycobacterium tuberculosis: The First Case in Korea

A slowly growing, non-chromogenic mycobacterial strain was isolated from sputum and bronchial lavage fluid samples of a patient presenting with productive cough, blood-tinged sputum, low-grade fever, and weakness. A positive acid-fast bacilli sputum smear result prompted the initiation of an anti-tuberculosis regimen. Multiplex real-time PCR showed a negative result for Mycobacterium tuberculosis complex and a positive result for nontuberculous mycobacteria. The DNA chip test confirmed this organism as a member of the genus Mycobacterium, but could not specify the species. Interestingly, the mycolic acid patterns obtained by HPLC nearly overlapped with those of M. simulans. The sequences of the Mycobacterium 16S rRNA gene and 16S-23S internal transcribed spacer region were unique and were found to have 100% similarity with those of M. riyadhense. After a review of the literature, we report this case as the first Korean case of M. riyadhense lung infection.

Identification of Mycobacteria Species by HPLC and Species Distribution during Five Years at Ulsan University Hospital / 대한진단검사의학회지

BACKGROUND: Infections caused by mycobacteria have been significantly increasing. Due to the difficulty of making a decision about the pathogenicity of mycobacteria, species-level identification is very important for patients' diagnosis and treatment. The purpose of this study was to identify mycobacteria species using a high performance liquid chromatography (HPLC) method and to provide an initial database for the distribution of mycobacteria in Korea. METHODS: Acid fast bacteria isolated from 3,107 clinical specimens were identified by mycolic acid analysis using HPLC. The HPLC patterns were compared with those of standard mycobacteria species. RESULTS: The HPLC patterns were divided into single, double, and triple cluster groups, each group comprising 9, 20, and 4 species, respectively. Mycobacteria and non-tuberculous mycobacteria (NTM) were identifies by HPLC at the rates of 99.5% and 95.6%, respectively. NTM was isolated in 12.4% of the mycobacteria positive specimens. This study also found that there were 20 different NTM species with the distribution of each species ranging from 0.3% to 15.9% of the total NTM. While the rate of NTM has been increasing in Korea, M. avium-intracellulare, M. fortuitum, and M. chelonae are relatively decreasing, and M. kansasii and M. gordonae are relatively increasing. CONCLUSIONS: HPLC method was highly discriminative for the identification of NTM in clinical specimens.

Linfadenitis causada por Mycobacterium malmoense en paciente infectado con virus de inmunodeficiencia humana / Lymphadenitis caused by Mycobacterium malmoense in HIV infected patient

Se reporta el primer caso cubano de micobacteriosis causada por Mycobacterium malmoense en un paciente infectado por el virus de inmunodeficiencia humana (VIH), el cual presentaba adenopatías ulcerativas submandibulares. A partir de las muestras tomadas de las lesiones ulceradas, se aisló una cepa de micobacteria no pigmentada de crecimiento lento, perteneciente al grupo I de Runyon, posteriormente fue clasificada por test bioquímico y por el análisis de las fracciones de ácidos micólicos, como Mycobacterium malmoense.

Identification of mycobacteria by mycolic acid pattern

Background. Tuberculosis caused by Mycobacterium tuberculosis is a public health problem which has increased in importance during the last 12 years, due in part to the increasing number of cases cuased by the association of acquired immunodeficiency syndrome (AIDS) and the appearance of multiple drug-resistant strains. Other mycobacteria which are often indistinguishable from tuberculosis have also increased. Methods. Mycolic acid patterns were obtained from 53 clinical isolated of sputum, cerebrospinal fluid, bronchial washing, corneal ulcer, and bone marrow, as well as from 11 acid-fast stain smear-positive clinical specimens. Standardized mycolic acid extraction method was used to ensure the maximal extraction of mycolic acid derivates to enhace the sensitivity of the method. A chromatographic column different from what others have employed and a different gradient elution from those reported in the literature were used, making a correlation between retention times of the chromatographic peaks obtained in this study and those previously reported for mycolic acid patterns from a strain of Mycobacterium avium necessary. Then, a comparison of retention times of mycolic acid pattern obtained in this study and those previously reported in the literature was carried out. Strains were identified as Mycobacterium tuberculosis complex, Mycobacterium avium complex, Mycobacterium fortuitum, Mycobacterium chelonae and Mycobacterium kansasii in less than 24 hours. Results. In direct analysis of acid-fast stain smearpositive from 1+ to 4+ specimens, mycolic acid patterns were identified as Mycobacterium tuberculosis complex, Mycobacterium avium complex, Mycobacterium chelonae, and Mycobacterium kansasii, with a strong signal even in light 1+ positive samples. conclusions: The results showed that identification of mycobacteria through mycolic acid pattern is a rapid, sensitive, and very useful method for identification of mycobacteria in the early diagnosis of the mycobacteriosis

Identificación de Mycobacteium tuberculosis mediante el análisis del perfil de ácidos micólicos por cromatografía líquida de alta presión (HPLC) / Identification of Mycobacterium tuberculosis through the analysis profile of mycolics acids by high-pressure liquid chromatography (HPLC)

Con el fin de validar una técnica de cromatografía líquida de alta presión (HPLC) para la identificación de Mycobacterium tuberculosis, se evaluaron 164 aislamientos de Mycobacterium spp. entre octubre de 1994 y octubre de 1995 en la Corporación para Investigaciones Biológicas (CIB). Todas las cepas provenían de pacientes y pertenecían a la colección de cepas del Laboratorio de Bacteriología de la CIB y fueron identificadas tanto por las pruebas bioquímicas tradicionales como por HPLC: Las pruebas bioquímicas se consideraron como el estándar de oro. Según éstas, 80 cepas fueron identificadas como M. tuberculosis y 84 como diferentes a M. tuberculosis. Dos cepas de M.Tuberculosis fueron identificadas en forma incorrecta por HPLC, una de ellas fue identificada como M. bovis-BCG y la otra como M. intracellulare. La sensibilidad de HPLC para la identificación de M. tuberculosis fue de 97,5 por ciento, la especificidad fue de 100 por ciento, el valor predictivo positivo de la prueba de 100 por ciento y el valor predictivo negativo de 97,7 por ciento