BACKGROUND Bleach-sedimentation may improve microscopy for diagnosing tuberculosis by sterilising sputum and concentrating Mycobacterium tuberculosis. We studied gravity bleach-sedimentation effects on safety, sensitivity, speed and reliability of smear-microscopy. METHODS This blinded, controlled study used sputum specimens (n = 72) from tuberculosis patients. Bleach concentrations and expos...

UNLABELLED The resurgence of Mycobacterium tuberculosis in association with HIV infection has focussed much attention in the rapid diagnosis of high risk cases. Infection with HIV is known to alter the presentation of pulmonary tuberculosis. The present study was under taken to compare the efficacy of fluorochrome stain (Fl) with conventional Ziehl Neelsen (ZN) stain in the diagnosis of pulmona...

The present study tests the utility of the in situ hybridization procedure for M. leprae rRNA in the histological diagnosis of early leprosy and clinically suspect leprosy, both diagnostically demanding situations. The histological confirmation obtained with routine histopathology (Haematoxylin-Eosin staining for studying morphologic alterations and Fite-Faraco staining for demonstration of aci...

Of the many chemical methods designed to aid the demonstration of acid-fast bacilli in sputum, the majority prove unsatisfactory in some respect when tested in the laboratory. The ideal method must first kill contaminating organisms in the specimen and liquefy or homogenize the mucopurulent constituents so that bacilli present can be concentrated by centrifugation. It must also leave deposited ...

When many infectious units of 1-3 bacilli are inhaled, a phenotypically hardy bacillus is likely to be among them. In addition, the alveolar macrophages apparently vary in their capacity to destroy bacilli [1]. Staining for acid-fast bacilli is very useful for demonstrating M. tuberculo‐ sis (A). Fig. 1 reveals histologic manifestation of tuberculosis over the time course. Histologi‐ cally, tub...

An eight-year-old, 4.9 kg, intact male mongrel dog presented with progressive weight loss, anorexia, vomiting, diarrhoea, and open-mouth breathing. A thoracic radiograph showed significant pleural effusion. Upon removal of the pleural effusion, an oval-shaped soft-tissue density mass was identified above the heart base. Two months later, the dog’s condition worsened severely, and he was euthani...

BACKGROUND The viable mycobacterial bacilli can sometimes form granules in the Mycobacterium Growth Indicator Tube (MGIT) to produce instrument-negative outcomes when BACTEC MGIT 960 culture is performed. The cause of this phenomenon has never been analyzed. METHODS Thirty-one instrument-negative, granule presenting MGIT vials were collected for conducting acid-fast staining and also liquid a...

Cytologic diagnosis of mycobacterial infection has conventionally depended on the recognition of granulomatous inflammation with caseous necrosis and the identification of acid-fast bacilli with special stains. Immunocompromised patients however may not mount the expected response. Mycobacteria can be seen as negative images in fine needle aspiration cytologic smears from patients with acquired...

A unique hallmark of tuberculosis is the granulomatous lesions formed in the lung. Granulomas can be heterogeneous in nature and can develop a necrotic, hypoxic core which is surrounded by an acellular, fibrotic rim. Studying bacilli in this in vivo microenvironment is problematic as Mycobacterium tuberculosis can change its phenotype and also become acid-fast negative. Under in vitro models of...

BACKGROUND Tuberculous lymphadenitis (TBLN) is the most common form of extrapulmonary tuberculosis. The cytomorphological features of lymph node smears have reduced specificity for the diagnosis of tuberculosis. The diagnosis of TBLN with direct smear microscopy lacks sensitivity due to the limited number of bacilli in lymph node aspirate. Therefore, we aimed to assess whether the concentration...