Sequential adaptation in latent tuberculosis bacilli: observation by atomic force microscopy (AFM)

International Journal of Clinical and Experimental Medicine

Ali Akbar Velayati¹  Muayad Aghali Merza¹  Poopak Farnia¹  Nikolai Nikolaevich Poleschuyk¹  Parissa Farnia¹  George Ignatyev¹  Mohammad Reza Masjedi¹  Jalladein Ghanavi¹  Payam Tabarsi¹  Gennady Konstantinovich Zhavnerko¹ 

关键词: Latent TB bacilli;    oxygen depletion;    atomic force microscopy;   

DOI  :  

学科分类：医学（综合）

来源: e-Century Publishing Corporation

【 摘 要 】

Mycobacterium tuberculosis (MTB) can persist within the human host for years without causing disease, in a syndrome known as latent tuberculosis. The mechanisms by which M. tuberculosis establishes a latent metabolic state is unknown, but it is hypothesized that reduced oxygen tension may trigger the bacillus to enter a state of latency. Therefore, we are studying anaerobic culture of M. tuberculosis (H37RV) as a model of latency. For the first time, the sequential adaptation of latent bacilli (every 90 days for 48 months) viewed under Atomic Force Microscopy (AFM). Two types of adaptation were observed and are described here. First, cells are undergoing temporary adaptation (from 1 to 18 months of latency) that includes; thickening of cell wall (20.5±1.8 nm versus 15.2±1.8 nm, P<0.05), formation of ovoid cells by “folding phenomena”(65-70%), size reduction (0.8±0.1 μm versus 2.5±0.5 μm), and budding type of cell division (20-25%).A second feature include changes that accompany development of specialized cells i.e., production of spore like cells (0.5±0.2 μm) and their progeny (filterable non -acid fast forms; 150 to 300 μm in size). Although, these cells were not real spore because they fail to form a heat resistant colony forming units, after incubation for 35-40 min at 65°C. The filterable non-acid fast forms of bacilli are metabolically active and increased their number by symmetrical type of cell-division. Therefore, survival strategies that developed by M. tuberculosis under oxygen limited condition are linked to its shape, size and conspicuous loss of acid fastness.

【 授权许可】

Unknown