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1.
Rev. Soc. Bras. Med. Trop ; 54: e0728-2020, 2021. tab, graf
Article in English | LILACS | ID: biblio-1155535

ABSTRACT

Abstract INTRODUCTION: Mycobacterium tuberculosis (MTB) is a causative agent of tuberculosis (TB) that causes death worldwide. METHODS: MTB was subjected to phenotypic drug-susceptibility tests (DST), and drug-resistant genes were sequenced. RESULTS: Previously treated patients were more likely to have positive smear results and exhibit drug resistance. New patients were more likely to be mono SM-resistant and less likely to be INH- and RIF-resistant. The most common mutations were katG (S315T), rpoB (S450L), rpsL (K43R), and embB (M306V). CONCLUSIONS: The proportion of mono-SM-resistant TB among new patients was higher.


Subject(s)
Humans , Pharmaceutical Preparations , Tuberculosis, Multidrug-Resistant , Mycobacterium tuberculosis/genetics , Bacterial Proteins/genetics , Microbial Sensitivity Tests , China , Mutation , Antitubercular Agents/pharmacology
2.
Acta Pharmaceutica Sinica ; (12): 1768-1773, 2020.
Article in Chinese | WPRIM | ID: wpr-825171

ABSTRACT

Polyketide synthase 13 (Pks13) performs a critical role in the final assembly step of mycolic acid synthesis in Mycobacterium tuberculosis. The inhibition of Pks13 can influence the biosynthesis of mycolic acid, which leads to Mycobacterium tuberculosis cell death. Researchers have discovered Pks13 inhibitors with five chemical scaffolds as antituberculosis agents. Herein, we summarize recent advances in the study of Pks13 inhibitors including the process of discovery, the mechanism of action and structure-activity relationships.

3.
J Biosci ; 2019 Mar; 44(1): 1-7
Article | IMSEAR | ID: sea-214306

ABSTRACT

In today’s era tuberculosis is a major threat to human population. The lethality of this disease is caused by very efficientlythrived bacteria Mycobacterium tuberculosis (M. tuberculosis). Ca2? plays crucial role in maintenance of cellular homeostasis. Bacilli survival in human alveolar macrophages majorly depends on disruption in Ca2? signaling. Bacilli sustainability in phagosome lies in the interruption of phagolysosomal fusion, which is possible because of low intracellularCa2? concentration. Bacilli contain various Ca2? binding proteins which help in regulation of Ca2? signaling for its ownbenefit. For the survival of pathogen, it requires alteration in normal Ca2? concentration in healthy cell. In this review weaim to find the various Ca2? binding domains which are present in several Ca2? binding proteins of M. tuberculosis andvariety of roles played by Ca2? to survive bacilli within host cell. This manuscript emphasizes the Ca2? binding domainspresent in PE_PGRS group of gene family and their functionality in M. tuberculosis survival and pathogenesis.

4.
Bol. méd. Hosp. Infant. Méx ; 74(1): 27-33, ene.-feb. 2017. tab, graf
Article in Spanish | LILACS-Express | LILACS | ID: biblio-888593

ABSTRACT

Resumen: Introducción: La tuberculosis (TB) continúa siendo un reto ya que las formas graves se presentan con mayor frecuencia en los menores de 5 años y el diagnóstico es complejo. El objetivo del presente trabajo fue describir las formas de presentación clínica, frecuencia, métodos de diagnóstico empleados y respuesta al tratamiento en niños con TB atendidos en un hospital de tercer nivel. Métodos: Se diseñó un estudio retrospectivo, descriptivo, de una cohorte de casos consecutivos atendidos desde enero de 2010 hasta diciembre de 2013. Se revisaron 93 expedientes clínicos de niños con diagnóstico de TB de acuerdo con la definición de la NOM-006-SSA2-2013. Se utilizó estadística descriptiva para el análisis. Resultados: El 58% de 93 niños fueron pacientes de sexo masculino con una media de edad de 7 años. El 97% contaba con antecedente de vacunación BCG; el 6% tuvo contacto con algún caso de TB. Las formas clínicas más frecuentes fueron la TB pulmonar (30.1%), ganglionar (24.7%), miliar/diseminada (16.1%), meníngea (13%) y ósea (7.5%). Los síntomas más comunes fueron fiebre y pérdida de peso (50% y 40%, respectivamente). El BAAR y el cultivo fueron positivos en el 26% y el 7% de todos los casos, respectivamente. El estudio histopatológico fue concluyente en el 90%. El tratamiento fue exitoso en el 94.6%, sin mortalidad asociada. Conclusiones: La asociación del cuadro clínico con las alteraciones en la radiografía de tórax y PPD positivo son útiles para establecer el diagnóstico presuntivo e iniciar el manejo oportuno.


Abstract: Background: Tuberculosis (TB) remains a challenge because severe forms occur most frequently in children under 5 years of age and the diagnosis is complex. The objective of this paper was to describe the clinical presentation, frequency, diagnostic methods used and response to treatment in children with TB treated at a tertiary level hospital. Methods: The study was retrospective and descriptive of a cohort of consecutive cases treated from January 2010 to December 2013. Ninety-three medical records of children diagnosed with TB according to the definition of the NOM-006-SSA2-2013 were reviewed. Descriptive statistics were used for the analysis. Results: From 93 children, 58% were male (mean age of 7 years), 97% with a history of BCG vaccination, and 6% had contact with a TB case. The most frequent clinical forms were pulmonary (30.1%), lymph node (24.7%), miliary/disseminated (16.1%), meningeal (13%), and osteal TB (7.5%). The most common symptoms were fever and weight loss (50% and 40%, respectively). BAAR and culture were positive in 26% and 7% of all cases, respectively. The histopathological study was conclusive in 90% of the cases. The treatment was successful in 94.6%, with not associated mortality. Conclusions: The association of clinical symptoms with alterations in chest radiography and positive PPD are useful in establishing the presumptive diagnosis and an early and appropriate treatment.

6.
Article in Chinese | WPRIM | ID: wpr-707188

ABSTRACT

Objective To screen and validate the major histocompatibility complex class-Ⅰ(MHC-Ⅰ) restricted tuberculosis peptides as potential diagnostic reagents in tuberculosis interferon-gamma release assay (IGRA) used among human immunodeficiency (HIV)-infected population.Methods Candidate peptides were encoded by Mycobacterium tuberculosis (TB) RD (Region of difference).Computer software was used to predict and select CD8+ T cell epitopes restricted by MHC-Ⅰ molecules with high frequency and high affinity among HIV-infected people.Then peptides containing CD8+ T cell epitope were synthesized and screened in vitro.The sensitivity and specificity of IGRA using the above mixed peptides as stimulants were compared with those of IGRA using early secretory antigen target-6 (ESAT-6,molecular weight of 6 000) and culture filtrate protein-10 (CFP-10,molecular weight of 10 000) as stimulants among HIV-infected population.Results Eight overlapping peptides,including Rv0222176-191,Rv1980c122-138,Rv1985c105-120,Rv3425141-165,Rv3873133-151,Rv3873158-166,Rv387878-86,Rv3879c673-690,were obtained finally,which were able to stimulate the production of interferon-gamma from peripheral CD8+ T cells of tuberculosis patients,but not from peripheral blood mononuclear cells (PBMC) of healthy controls.Among the 25 patients with HIV/TB co-infection,the sensitivities of IGRA using the combination peptides (CP) and that using rESAT-6/CFP-10 (CE) were low (68% vs 48%,x2 =2.052,P=0.152).However,the sensitivity increased to 92% by using the combination of CP and CE,which was significantly higher than that using rESAT-6/CFP-10 alone (x2 =11.523,P < 0.01),and the specificity was not affected.Conclusion These RD peptides with CD8+ T cell epitopes can increase the sensitivity of IGRA in detecting HIV/TB co-infection,which may improve the detection rate of tuberculosis in HIV infected population.

7.
Article in Chinese | WPRIM | ID: wpr-508605

ABSTRACT

Objective To explore protein microarray chip diagnostic value for patients with active and inactive tuberculosis.Methods 178 cases of active patients tuberculosis and 79 cases of inactive tuberculosis patients and 92 cases of healthy control using protein microarray chip detection.Results Tuberculosis protein chip had a diagnostic value for tuberculosis and the positive rate is 58.4%; combined the diagnostic value of three kinds of proteins is higher than the diagnostic value of a single protein;16 kD protein of inactive tuberculosis positive rate was 16.4%, better than the positive rate of 3.4% for active tuberculosis (P<0.05).Conclusion Tuberculosis protein chip has a diagnostic value for active tuberculosis and inactive tuberculosis.16 kD protein positive rate more than 38 kD protein in patients with inactive tuberculosis (P<0.05).

8.
Article in English | WPRIM | ID: wpr-625145

ABSTRACT

Background: Drug resistant tuberculosis (DR-TB) remains a public health issue that is of major concern on a global scale. The characterisation of clinical isolates may provide key information regarding the underlying mechanisms of drug resistance, and helps to augment therapeutic options. This study aims to evaluate the frequency of gene mutations associated with Rifampicin (RIF) and Isoniazid (INH) resistance among nine clinical isolates. Methods: A total of nine drug resistant Mycobacterium tuberculosis clinical isolates were screened for genetic mutations in rpoB and katG using polymerase chain reaction (PCR) amplification and DNA sequencing. Genotypic analysis was performed to detect the mutations in the sequence of the target genes. Results: Our findings reveal that 80% of the isolates possess mutations at codon 119 (His119Tyr) and 135 (Arg135Trp and Ser135Leu) within the rpoB gene; and 70% possess mutations in the katG gene at codon 238 with amino acid change (Leu238Arg). Conclusion: Findings from this study provide an overview of the current situation of RIF and INH resistance in a hospital Universiti Sains Malaysia (HUSM) located in Kelantan, Malaysia, which could facilitate molecular-based detection methods of drug-resistant strains. Further information regarding the molecular mechanisms involved in resistance in RR-/MDR-TB should be addressed in the near future.


Subject(s)
Mycobacterium tuberculosis
9.
Rev. Inst. Nac. Hig ; 47(1-2): 14-17, 2016. ilus, graf
Article in Spanish | LILACS, LIVECS | ID: biblio-1005334

ABSTRACT

La tinción de Ziehl Neelsen (ZN), es una técnica de coloración de microorganismos para la identificación de patógenos, como Mycobacterium tuberculosis causante de la tuberculosis, que requiere de tres (03) soluciones: Carbol Fucsina Fenicada (Fucsina Básica), Azul de Metileno al 1% y Solución Decolorante, que se elaboran en la Sección de Reactivos y Colorantes del Instituto Nacional de Higiene "Rafael Rangel" y se emplean en el diagnóstico de tuberculosis. Esta investigación surgió con el propósito de comprobar el tiempo de caducidad y condiciones de almacenamiento de dichos productos y presentarlos en un estuche tipo kit para su distribución, en apoyo a la Red Nacional de Laboratorios de Salud Pública y comercialización con otros entes. Se realizó el ensayo de tres (3) lotes del kit de Ziehl Neelsen; con su respectiva contramuestra que fue evaluada en el análisis final. Se registraron los parámetros físicos de temperatura y humedad relativa bajo condiciones normales de almacenamiento en el laboratorio, con las muestras protegidas de la luz. Se evaluó la funcionalidad por medio de la tinción ZN observada bajo microscopio, de tres (03) muestras con ATCC 700686: M. peregrinum y ATCC 29213: S. aureus por lote; tomando en cuenta el exceso de colorante, y la definición de las coloraciones. Estas evaluaciones se realizaron durante dos (02) años encontrándose como resultado que física y funcionalmente los productos contentivos en el kit se mantenían estables, fijándose un tiempo de caducidad de dos (02) años.


Ziehl Neelsen (ZN) is a staining technique of microorganisms for the identification of pathogens as Mycobacterium tuberculosis, causative of tuberculosis, which requires three (03) solutions: Carbol Fuchsin combined with Phenol (Basic Fuchsin), Methylene Blue 1% and Bleaching solution, which are prepared in Section of Reagents and Coloring of the Instituto Nacional de Higiene "Rafael Rangel" and are used in the diagnosis of tuberculosis. This investigation was made with the purpose of checking the shelf life and storage conditions of these products and present them in a kit type container for distribution in support of the National Network of Public Health Laboratories and marketing with other entities. The analysis was performed in three (3) batches of the Ziehl Neelsen kit; with their respective counter sample that was evaluated in the final analysis. The physical parameters of temperature and relative humidity were recorded in the laboratory under normal storage conditions with samples protected from light. The functionality was evaluated through ZN staining being observed under a microscope three (03) samples with ATCC 700686: M. peregrinum and ATCC 29213: S. aureus by Batch; taking into consideration the excess dye, and the definition of the colors. These evaluations were conducted for two (02) years found as main result that physically and functionally the products in the kit were stable, and can set an expiration time of two years.


Subject(s)
Humans , Male , Female , Child , Aged , Aged, 80 and over , Reagent Kits, Diagnostic , Mycobacterium tuberculosis , Public Health
10.
Rev. argent. microbiol ; 47(1): 47-49, Mar. 2015.
Article in English | LILACS, BINACIS | ID: biblio-1171810

ABSTRACT

The possibility to obtain DNA from smears is a valuable alternative to remedy the lack of samples when they are totally used for bacilloscopy; this technique solves the biosafety problem related to a possible accident with the transportation of flasks containing potentially transmissible clinical samples. Hence, the purpose of this study was to utilize the insertion sequence IS6110 for amplification of DNA from a smear-positive sample for tuberculosis (TB) diagnosis. Among the 52 positive bacilloscopies, sensitivity, specificity, positive predictive value and negative predictive value were 52.3%, 100%, 100% and 89.7%, respectively whereas accuracy was 90.7%. The IS6110-based PCR for TB diagnosis developed in DNA extracted from a positive smear is a fast, simple, specific, and safe method


La posibilidad de obtener ADN a partir de frotis es una valiosa alternativa para remediar la falta de muestras cuando estas son totalmente utilizadas para la baciloscopia; esta opción soluciona, además, el problema de bioseguridad asociado a la posibilidad de accidente al transportar frascos que contienen muestras clínicas potencialmente infectivas. Por lo tanto, el propósito de este estudio fue utilizar para el diagnóstico de la tuberculosis la secuencia de inserción IS6110 para amplificación del ADN a partir de frotis que resultaron positivos por baciloscopia. Del análisis de 52 baciloscopias positivas surge que la sensibilidad, la especificidad, el valor predictivo positivo y el valor predictivo negativo de esta técnica fueron, respectivamente, del 52,3%, del 100%, del 100% y del 89,7%; y la precisión fue del 90,7%. La PCR IS6110 para el diagnóstico de tuberculosis, desarrollada con ADN extraído de frotis positivos, es un método rápido, simple, específico y seguro


Subject(s)
Tuberculosis/diagnosis , Polymerase Chain Reaction/methods , Containment of Biohazards/methods
11.
Article in English | IMSEAR | ID: sea-157698

ABSTRACT

One-third of the world’s population is estimated to be infected with M.tuberculosis. Timely and accurate diagnosis is pivotal in the management of the disease. Conventional tests, although accurate, are time consuming as compared to the more promising latest molecular techniques like real-time PCR which are rapid, reproducible and reliable. Objective : The aim of the study is to compare the real-time PCR with culture method in the diagnosis of tubercular lymphadenopathy. Material and Methods: Present study included 40 patients belonging to the age group 0-40 years and presenting as cervical lymphadenopathy, attending the indoor and out-patient of Department of TB & Chest Diseases, S.N. Medical College, Agra (U.P.) from Jan’2009 to June’2010. All patients were subjected to routine investigations, e.g. hemogram, montoux test, Chest skiagram, AFB staining, and sputum examination. Lymph node aspirate were subjected to decontamination, DNA isolation and Real time PCR( q PCR). Also specimen were simultaneously put to culture on L.J. Media. Results of both modalities compared. Results: Conventional culture method was able to detect M.tuberculosis in 75% of the cases as compared to real-time PCR which was positive in 77.5% with comparable sensitivity (100% vs 96.7%) and specificity (100% vs 87.5%). Conclusion: Conventional culture method is gold standard in the diagnosis of tuberculosis since long but recent molecular assays like Real-time PCR is one of the latest addenda to the armamentarium for the rapid and accurate diagnosis of M.tuberculosis. Needless to say, early diagnosis is advantageous to the management of tuberculosis.


Subject(s)
Adolescent , Adult , Child , Child, Preschool , Early Diagnosis , Female , Humans , India/epidemiology , Infant , Infant, Newborn , Lymphatic Diseases/diagnosis , Lymphatic Diseases/therapy , Male , Real-Time Polymerase Chain Reaction/methods , Tuberculosis/diagnosis , Tuberculosis/therapy , Young Adult
12.
Article in English | WPRIM | ID: wpr-379248

ABSTRACT

Abdominaltuberculosis (TB) is generally responsive to medical treatment, and earlydiagnosis and management can prevent unnecessary surgical intervention. However, there is a needfor intravenous therapy for severe forms of tuberculosis with extensivegastrointestinal involvement. The authors report an immunocompetent patientwith gastrointestinal TB who was successfully managed with a combination ofsurgical intervention and anti-TB medications, and discuss the importance ofinjectable anti-TB medications in the management of severe gastrointestinal TB.The present case report illustrates a model for assessment and intervention in severeforms of gastrointestinal TB.

13.
Article in English | WPRIM | ID: wpr-377082

ABSTRACT

Abdominal tuberculosis (TB) is generally responsive to medical treatment, and early diagnosis and management can prevent unnecessary surgical intervention. However, intravenous therapy is needed for severe forms of tuberculosis with extensive gastrointestinal involvement. The authors report an immunocompetent patient with gastrointestinal TB who was successfully managed with a combination of surgical intervention and anti-TB medications, and discuss the importance of injectable anti-TB medications in the management of severe gastrointestinal TB. The present case report provides a model for assessment and intervention in severe forms of gastrointestinal TB.

14.
Br J Med Med Res ; 2015; 9(2): 1-6
Article in English | IMSEAR | ID: sea-180847

ABSTRACT

Aim: To evaluate the methodology of MTT tube assay and compare it with standard proportion method for detection of drug susceptibility of M. tuberculosis to rifampicin (RIF) and isoniazid (INH). Study Design: Prospective. Place and Duration of Study: Sher-i-Kashmir Institute of Medical Sciences, Kashmir, India. One year study. Methodology: MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide] assay was performed on 60 clinical isolates of M. tuberculosis. An inoculum of 107CFU/ml prepared in Middlebrook 7H9 with OADC (Oleic acid, albumin, dextrose and catalase) was chosen as standard. For each drug three tubes were used, one drug containing (INH 0.2 μg/ml or RIF 1 μg/ml), second inoculum control and third blank control. The method was performed after incubating the tubes at 37°C for 4 days for RIF and 7 days for INH. Results were read visually and by spectrophotometer at 570 nm. Relative optical density units of 0.2, was taken as cutoff. Results of drug susceptibility were compared with those obtained by Lowenstein Jensen proportion method. Results: For RIF, sensitivity was 88.9% and 94.4%; specificity was 100% and 97.6% for visual MTT and MTT by RODU respectively. For INH similar sensitivity of 95.1% was seen while specificity was 97.0% and 95.0% by visual MTT and MTT by RODU respectively. There was almost perfect agreement between proportion and MTT method for both drugs. Turn-around time for MTT assay was 7 days. Conclusion: The MTT tube assay can be used for rapid drug susceptibility testing of M. tuberculosis to RIF and INH.

15.
Indian J Med Microbiol ; 2014 Oct-Dec ; 32 (4): 434-437
Article in English | IMSEAR | ID: sea-156963

ABSTRACT

In India, extrapulmonary tuberculosis (EPTB) accounts for 10 - 15% of all types of tuberculosis. To identify and compare predominant spoligotypes and drug‑resistance patterns in strains of Mycobacterium tuberculosis isolated from extrapulmonary and pulmonary specimens in central India, drug susceptibility testing and spoligotyping were carried out. Spoligotyping data was analyzed using SITVIT2 database. ST11/EAI3_Ind with 33% isolates among extrapulmonary specimens and ST26/ CAS1_DEL with 28% isolates among pulmonary specimens were the most predominant lineages. Multidrug resistance was found in 5.5% of the strains isolated from extrapulmonary specimens in contrast to 17% isolated from pulmonary specimens.

16.
Indian J Med Microbiol ; 2014 Oct-Dec ; 32 (4): 398-403
Article in English | IMSEAR | ID: sea-156955

ABSTRACT

Background: Early detection of multidrug‑resistant tuberculosis (MDR‑TB) is essential to prevent its transmission in the community and initiate effective anti‑TB treatment regimen. Materials and Methods: High‑resolution melting curve (HRM) analysis was evaluated for rapid detection of resistance conferring mutations in rpoB and katG genes. We screened 95 Mycobacterium tuberculosis clinical isolates including 20 rifampin resistant (RIF‑R), 21 isoniazid resistant (INH‑R) and 54 fully susceptible (S) isolates determined by proportion method of drug susceptibility testing. Nineteen M. tuberculosis isolates with known drug susceptibility genotypes were used as references for the assay validation. The nucleotide sequences of the target regions rpoB and katG genes were determined to investigate the frequency and type of mutations and to confirm HRM results. Results: HRM analysis of a 129‑bp fragment of rpoB allowed correct identification of 19 of the 20 phenotypically RIF‑R and all RIF‑S isolates. All INH‑S isolates generated wild‑type HRM curves and 18 out of 21 INH‑R isolates harboured any mutation in 109‑bp fragment of katG exhibited mutant type HRM curves. However, 1 RIF‑R and 3 INH‑R isolates were falsely identified as susceptible which were confirmed for having no mutation in their target regions by sequencing. The main mutations involved in RIF and INH resistance were found at codons rpoB531 (60% of RIF‑R isolates) and katG315 (85.7% of INH‑R isolates), respectively. Conclusion: HRM was found to be a reliable, rapid and low cost method to characterise drug susceptibility of clinical TB isolates in resource‑limited settings.

17.
Article in English | IMSEAR | ID: sea-153412

ABSTRACT

Aims: Detection of drug resistance M. tuberculosis isolates is one of the most important strategies to control the disease. Nowadays, with advances in molecular technology, various methods are available to detect drug resistant M. tuberculosis strains such as those based on capture specific probes. In this study, we aimed to investigate the frequency of mutation in the M. tuberculosis -rpoB gene by Polymerase Chain Reaction based on Enzyme Linked Immuno Sorbent Assay (PCR-ELISA) detection. Methodology: Thirty-three culture positive isolates were randomly selected for this study. All the isolates were subjected to a drug Susceptibility Test (DST) using the proportion method. Then the ability and the efficiency of Multiplex Allele Specific PCR (MAS-PCR) and PCR-ELISA to detect Rif resistant (Rifr) M. tuberculosis isolates was compared and evaluated. Results: Mutation of rpoB gene was detected in 19/33 isolates (57.6%) by PCR-ELISA. Hybridization with the specific mutant probes 516 and 526 codon occurred in 1/33 isolates each (3% respectively). Hybridization with the specific mutant probe 531 occurred in 13/33 isolates (39.4%). Three isolates (9.2%) showed simultaneous mutation in codons 516 and 531. The sensitivity and specificity of MAS-PCR in comparison to the Proportional Method was 100%. On the other hand, PCR-ELISA showed 75% sensitivity and 69.2% specificity. The positive predictive value for the PCR-ELISA method was 78.9% and the negative predictive value was 64.3%.The general efficacy of test was 72.7%. Conclusion: The study showed that the sensitivity and specificity of PCR-ELISA to detect mutations in the rpoB gene in Drug Resistant strains was low. Furthermore, this proved to be a complex, time consuming and expensive test. Therefore, this test is not recommended for determining Rifampicin resistance in M. tuberculosis strains.

18.
Article in English | IMSEAR | ID: sea-159981

ABSTRACT

Summary: Primary tuberculous myositis without underlying pathology has been sparingly reported in medical literature. We report a case of primary tuberculous myositis of left upper arm in a seven-year-old boy. He presented with gradually increasing swelling on the medial aspect of the left arm. Ziehl Neelsen staining of pus collected revealed acid fast bacilli morphologically resembling Mycobacterium tuberculosis and the same was grown on the culture. Histopathological findings were consistent with tuberculosis. The results were confirmed by Genotype MTBDRpluse line probe assay. He was treated with standard four-drug regimen to which he responded well with complete resolution of the lesion.


Subject(s)
Child , Humans , Male , Mycobacterium tuberculosis/epidemiology , Myositis/drug therapy , Myositis/epidemiology , Myositis/etiology , Tuberculosis/complications , Tuberculosis/drug therapy , Tuberculosis/epidemiology
19.
Article in English | IMSEAR | ID: sea-159975

ABSTRACT

Background: Cetyl pyridinium chloride (CPC) liquefied sputum was shown to reduce AFB smear positivity presumably damaging cell wall of M. tuberculosis. Settings: National Institute for Research in Tuberculosis, Chennai, (Tamil Nadu). Objective: To assess the cell wall damage of mycobacteria in CPC liquefied sputum, by Transmission Electron Microscopy (TEM) and mycobacteriophage adsorption studies. Methods: Pooled sputum sample from smear positive pulmonary TB patients was homogenized and liquefied with CPC. It was examined in TEM daily for four days, to assess cell wall damage of M. tuberculosis, and photomicrographs were taken. M. smegmatis mc2155, treated with CPC, was infected with mycobacteriophage (phAE129) to study phage adsorption on cell wall and plaque formation. CPC untreated sputum and M. smegmatis formed controls. Results: Photomicrographs showed that cell wall of M. tuberculosis was intact in controls and damaged in CPC preserved sputum for 96 hours. Plaque formation was seen and absent respectively in CPC untreated and treated M. smegmatis cells. Conclusion: Exposure to CPC damaged the cell wall of M. tuberculosis within 96 hours. Mycobacteriophage failed to form plaques after M. smegmatis mc2155 was treated with CPC implying inhibition of phage adsorption on damaged cell wall and thus providing a clue for poor staining and smear positivity in microscopy.


Subject(s)
Cell Wall/chemistry , Cell Wall/physiology , Cetylpyridinium/physiology , Microscopy, Electron, Transmission/methods , Mycobacteriophages/cytology , Mycobacteriophages/physiology , Mycobacterium tuberculosis/cytology , Mycobacterium tuberculosis/physiology
20.
Indian J Med Microbiol ; 2013 Jul-Sept; 31(3): 230-236
Article in English | IMSEAR | ID: sea-148089

ABSTRACT

Purpose: The emergence and spread of multidrug-resistant tuberculosis (MDR-TB) is a major public health problem. The diagnosis of MDR-TB is of paramount importance in establishing appropriate clinical management and infection control measures. The aim of this study was to evaluate drug resistance and mutational patterns in clinical isolates MDR-TB by GenoType® MTBDRplus assay. Material and Methods: A total of 350 non-repeated sputum specimens were collected from highly suspected drug-resistant pulmonary tuberculosis (PTB) cases; which were processed by microscopy, culture, differentiation and first line drug susceptibility testing (DST) using BacT/ALERT 3D system. Results: Among a total of 125 mycobacterium tuberculosis complex (MTBC) strains, readable results were obtained from 120 (96%) strains by GenoType® MTBDRplus assay. Only 45 MDR-TB isolates were analysed for the performance, frequency and mutational patterns by GenoType® MTBDRplus assay. The sensitivity of the GenoType® MDRTBplus assay for detecting individual resistance to rifampicin (RIF), isoniazid (INH) and multidrug resistance was found to be 95.8%, 96.3% and 97.7%, respectively. Mutation in codon S531L of the rpoB gene and codon S315T1 of katG genes were dominated in MDR-TB strains, respectively (P < 0.05). Conclusions: The GenoType® MTBDRplus assay is highly sensitive with short turnaround times and a rapid test for the detection of the most common mutations conferring resistance in MDR-TB strains that can readily be included in a routine laboratory workflow.

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