A
Anton Sebastian in A Dictionary of the History of Medicine, 2018
Acid-Fast Bacteria Certain bacteria are resistant to decoloration when stained with fuchsin. This was noted by Paul Ehrlich (1854–1915) in 1882. German bacteriologist Franz Ziehl (1857–1926) confirmed this and developed the method of acid-fast staining in 1883. The bacillus of leprosy (Hansen bacillus), later noted to have acid-fast properties, was discovered by Gerhard Henrik Armauer Hansen (1841–1912) in 1874. A second group of acid-fast bacilli, the tubercle bacilli, was discovered by Robert Koch (1843–1910) in 1882. The peculiar property of acid-fastness was studied by Edwin Klebs (1896), Robert Koch (1897) and Tamura (1913). Tamura isolated an alcohol from these bacteria which gave them the property of acid-fastness and named the substance ‘mykol’. See tubercle bacillus.
Diagnosis of Tuberculosis
Peter D O Davies, Stephen B Gordon, Geraint Davies in Clinical Tuberculosis, 2014
The examination of sputum is still the mainstay of diagnosis, and sputum is initially examined using smear microscopy. This is one of the oldest diagnostic tests in medicine and was developed more than 100 years ago. Its aim is to visualise the acid-fast bacilli, and it is the most frequently available test at the lower tiers of health systems. There are several staining methods for light and fluorescent microscopy. The most common stain for light microscopy is Ziehl–Neelsen (ZN) [4]. Fluorescent microscopy (FM) highlights the fluorescent bacilli, and results are read with microscopes that can produce fluorescent light. Smears for FM are stained using fluorescent dyes such as auramine-O, rhodamine, auraminerhodamine combinations, acridine orange and others and are counter-stained with potassium permanganate, which decreases the fluorescence of other particles.
Bacterial and Atypical Mycobacterial Infections
Clay J. Cockerell, Antoanella Calame in Cutaneous Manifestations of HIV Disease, 2012
Cutaneous infection with M. tuberculosis in a previously sensitized individual results in a skin condition known as tuberculosis verrucosa cutis. This is more common among healthcare workers who come in contact with infected patients, especially when they are exposed to secretions or body fluids. It is also known as pathologist’s warts or prosector’s warts as it is often caused by autoinoculation.33,34 It begins as one or more asymptomatic reddish-brown papules that develop a markedly verrucous surface with abundant crust. When diascopy is performed by pressing a glass slide on the lesion, there is a translucent ‘apple jelly’ appearance. Lesions may undergo necrosis and ulcerate although significant scarring is rare. Occasionally, pus may be expressed; however, in contrast to tuberculous chancre, lymphadenopathy is rare.34 The diagnosis is made by finding acid-fast bacilli in smears or in biopsy specimens and confirmed by cultures.
Evaluation of the performance of the BD MAX MDR-TB test in the diagnosis of Mycobacterium tuberculosis complex in extrapulmonary and pulmonary samples
Published in Expert Review of Molecular Diagnostics, 2021
Pınar Sağıroğlu, Mustafa Altay Atalay
Acid-fast bacteria (AFB) were studied with the Ziehl-Neelsen (ZN) staining method simultaneously in all samples included in the study. Mycobacterial cultures of samples were made in BACTEC MGIT 960 liquid culture (Becton Dickinson, USA) system and Lowenstein-Jensen (LJ) (RTA, Turkey) medium. The sodium hydroxide-N-acetyl-L-cysteine decontamination process was used for all specimens except cerebrospinal fluid (CSF), and then 200 µL of each sample was inoculated into LJ medium and 0.5-mL into MGIT tube and incubated. Liquid cultures were followed on the instrument for 42 days, solid cultures for 60 days. BD MGIT TBc ID Test (Becton Dickinson, USA), which detects MPT64 protein, was used to identify isolated strains. Strains positive with the TBc ID test were defined as MTC, and those with negative test results were defined as non-tuberculous mycobacteria (NTM). Antibiotic susceptibility tests of MTC strains against primary drugs (Isoniazid, rifampicin, streptomycin, and ethambutol) were performed using BD MGIT™-AST SIRE Test Kit (Becton Dickinson, USA).
Tuberculous cellulitis in an immunocompetent patient
Published in Baylor University Medical Center Proceedings, 2019
Pejman Rabiei, Merve Hasanov, Bobak Akhavan, Gabriel M. Aisenberg
Forty days later, the patient was readmitted with persistent erythema and worsening pain and skin discoloration (Figure 1). X-ray and magnetic resonance imaging of his left hand were concerning for osteomyelitis of the fourth digit phalanxes. Another punch biopsy was unremarkable. Debridement and irrigation of the affected digit followed, and a wedge of deep tissue was obtained for stain, culture, and PCR. The stain was positive for acid-fast bacilli. Treatment with ethambutol, clarithromycin, and rifampin was started for suspected Mycobacterium marinum infection. PCR for Mycobacterium tuberculosis was reported positive 3 weeks later. Isoniazid and pyrazinamide were added to the treatment. Two weeks later, the deep tissue culture grew M. tuberculosis and clarithromycin was discontinued. At that time, improvement of the skin lesions was noted (Figure 2). Chest x-ray was normal.
Evaluation of laboratory diagnostic approaches for tuberculous pleurisy
Published in Infectious Diseases, 2019
Xiao-Chun Shi, Yu-Ting Tan, Li-Fan Zhang, Yue-Qiu Zhang, Xiao-Qing Liu
In short, the diagnosis of tuberculous pleurisy is relatively difficult. Although there are various methods of laboratory examination, each has its own shortcomings. The detection rate of acid-fast staining is very low. Detection of MTB DNA in pleural effusion is rapid and convenient; however, the detection rate is low, and there is a possibility of false positives caused by nucleic acid contamination. The detection rate of mycobacteria in pleural effusion is lower than that of tests performed on other sample types and takes longer. China is a country with a high burden of TB, and T-SPOT.TB on pleural effusion has limited efficacy for differentiating active TB from latent TB infections. A comprehensive analysis of clinical data is necessary and important. Pleural biopsy is of great significance for the diagnosis of difficult cases and is worth popularizing.
Related Knowledge Centers
- Acid
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- Staining
- Mycolic Acid