کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8746024 1593301 2016 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
L-form transformation phenomenon in Mycobacterium tuberculosis associated with drug tolerance to ethambutol
موضوعات مرتبط
علوم زیستی و بیوفناوری ایمنی شناسی و میکروب شناسی ویروس شناسی
پیش نمایش صفحه اول مقاله
L-form transformation phenomenon in Mycobacterium tuberculosis associated with drug tolerance to ethambutol
چکیده انگلیسی
Objective/background: Cell wall-deficient bacterial forms (L-forms) may occur along with resistance to factors that trigger their appearance. It is of interest to study the relationship between the L-form transformation of Mycobacterium tuberculosis and the exhibition of drug tolerance to ethambutol (EMB), an inhibitor of cell wall synthesis. Methods: L-form variant was produced from a sensitive EMB strain of M. tuberculosis through a cryogenic stress treatment protocol and was subsequently cultivated in Middlebrook 7H9 semisolid medium, containing EMB in a minimal inhibitory concentration of 2 mg/L. Susceptibility to EMB of the parental strain and its L-form variant was evaluated phenotypically and using polymerase chain reaction-restriction fragment length polymorphism assay targeting a mutation in the embB306 gene fragment. Results: In contrast to the sensitivity to EMB of the parental strain, its L-form variant showed phenotypic resistance to high concentrations of EMB (16 mg/L), but the mutation in embB306 was not found. Electron microscopy observation of the L-form variant showed a heterogenic population of bacteria, with different degrees of cell wall deficiency, as well as cells of protoplastic type without cell walls. Of special interest were the observed capsule-like structures around the L-form cells and the biofilm-like matrix produced by the L-form population. Conclusion: We suggest that the expression of phenotypic resistance to EMB in M. tuberculosis can be associated with alterations or loss of cell walls in L-form bacteria, respectively, which results in a lack of a specific target for EMB action. In addition, production of capsule-like structures and biofilm matrix by L-forms could contribute to their resistance and survival in the presence of antibacterial agents.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Mycobacteriology - Volume 5, Issue 4, December 2016, Pages 454-459
نویسندگان
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