[The in vitro killing of intracellular Mycobacterium smegmatis by Mycobacteriophage].
OBJECTIVE
To study the effect of Mycobacteriophage on the lysis of intracellular Mycobacterium smegmatis.


METHODS
Peritoneal macrophages from BALB/C mice were incubated with Mycobacterium smegmatis for 4 h, and the extracellular bacteria were removed. Then the infected macrophages were treated for 2 h with normal saline, or different doses of Mycobacteriophages (2.1 x 10(7) PFU, 2.1 x 10(6) PFU, and 2.1 x 10(5) PFU, respectively), all in a volume of 0.1 ml, and then the extracellular phages and Mycobacterium smegmatis were removed by washing. After incubation for 24 h, the number of viable intracellular bacteria was determined. The intracellular changes after infection of host bacteria by bacteriophages in the macrophages were observed by electron microscopy.


RESULTS
The logarithm 10 of viable intracellular bacteria unit was 5.74 +/- 0.18 in the saline group, 4.77 +/- 0.08 in the high dose phage group (P < 0.01), 4.97 +/- 0.17 in the moderate dose phage group (P < 0.01), and 5.33 +/- 0.13 in the low dose phage group (P > 0.05). Electron microscopy confirmed the infection of intracellular bacteria by the bacteriophages and the production of filial bacteriophages.


CONCLUSIONS
Mycobacteriophages phagocytosed by macrophages are capable of killing the infected mycobacteria. The result suggests that the use of Mycobacteriophages is a potentially novel strategy in the treatment of intracellular bacterial infection.
Peng
Li
L
Department of Pulmonary Disease, First Affiliated Hospital of Chongqing University of Medical Sciences, Chongqing 400016, China.
Chen
Bao-wen
BW
Luo
Yong-ai
YA
Shen
Xiao-bing
XB
Li
You-lun
YL
Wang
Guo-zhi
GZ
D000818:Animals; D002478:Cells, Cultured; D017737:Macrophages, Peritoneal / Q000382:microbiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009160:Mycobacteriophages; D020102:Mycobacterium smegmatis / Q000821:virology*; D010587:Phagocytosis