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New Discoveries of Significance to the Prevention, Control, and Treatment of Leprosy
Published in Max J. Miller, E. J. Love, Parasitic Diseases: Treatment and Control, 2020
There has been extremely rapid progress in the last 5 years in characterizing the biochemistry of M. leprae, mainly by Wheeler and associates in Great Britain.19 The organism contains most pathways normally associated with glycolosis, the tricarboxylic acid cycle, the hexose monophosphate pathway, and glycerol catabolism and the like, and a major biochemical defect which prevents it from multiplying in vitro has not been identified. On the other hand, generally the metabolic activities of M. leprae are low, compared to cultivable mycobacteria. Catalase appears to be absent from M. leprae and the rate of de novo purine synthesis is very low, compared with the rate of purine scavenging. The organism has predominantly glycine in its cell wall peptidoglycans, rather than alanine. M. leprae lacks dicarboxymycolates which are present in most other mycobacteria and also seems to lack tuberculostearic acid.
Tuberculosis
Published in Thomas T. Yoshikawa, Shobita Rajagopalan, Antibiotic Therapy for Geriatric Patients, 2005
Other diagnostic methods for TB that have been clinically evaluated include serology (e.g., ELISA, radioimmunoassay, latex particle agglutination assay) and gas chromatography assay for tuberculostearic acid (21). However, when applied to serum samples alone, these tests have not been considered sensitive and specific enough to be used as the sole diagnostic procedure for TB. Nucleic acid amplification (NAA) tests such as polymerase chain reaction and other methods for amplifying DNA and RNA may facilitate rapid detection of Mtb from respiratory specimens; the interpretation and use of the NAA test results has been recently updated by the CDC (26). Similar techniques that utilize DNA probes can be used to track the spread of the organism in epidemiologic studies and may be used to predict drug resistance prior to the availability of standard results; such methods are presently being used in some laboratories. Rapid diagnosis of TB is important in elderly patients, patients with immunocompromised states and with MDR TB.
Diagnostic Challenge with Nocardia Subretinal Abscess: A Case Report from Tuberculosis-Endemic Region
Published in Ocular Immunology and Inflammation, 2019
Parthopratim Dutta Majumder, Madhura Mukherjee, Lily Therese, Lingam Gopal, Jyotirmay Biswas
Since its first published report in 1967, a number of reports and case series have been published on Nocardia subretinal abscess.1,3,8–11 Owing to its high vascularity, choroid is the most commonly involved structure in intraocular nocardiasis and hematogenous spread from distant sites especially lungs is responsible for intraocular involvement. Propensity of abscess formation by Nocardia has been attributed to tuberculostearic acid, a component of the cell membrane which aids in the suppurative inflammatory process that results into an abscess. Subretinal abscess always occurs due to infective etiologies and remains a diagnostic challenge to the treating ophthalmologists. It requires high index of suspicion as well as proper diagnostic evaluative procedure to clinch the diagnosis.
An evaluation of liposome-based diagnostics of pulmonary and extrapulmonary tuberculosis
Published in Expert Review of Molecular Diagnostics, 2020
Nikunj Tandel, Anish Z Joseph, Aishwarya Joshi, Priya Shrama, Ravi PN Mishra, Rajeev K. Tyagi, Prakash S Bisen
Attempts have been made over the years to develop serological or serodiagnostic methods for tuberculosis. One such approach makes use of tuberculostearic acid, a known marker present in the cerebrospinal fluid of tuberculosis meningitis [14]. This is a gas-liquid chromatography-dependent technique and moreover, the fact that pulmonary specimens having organisms other than M. tuberculosis might give a false positive is the major drawbacks to the technique [10]. On the other hand, the mass spectroscopy techniques are always useful for the identification of biomarkers/metabolites that are very specific for M. tuberculosis [15].