Interactions between Mycobacterium xenopi, amoeba and human cells

Area of Science:

• Microbiology
• Environmental Health
• Cell Biology

Background:

• Mycobacterium xenopi outbreaks are linked to contaminated water systems.
• M. xenopi interacts with biofilms and is hosted by Acanthamoeba.
• Understanding M. xenopi's interaction with hosts is crucial for public health.

Purpose of the Study:

• To investigate the interaction between M. xenopi and Acanthamoeba polyphaga.
• To examine M. xenopi's interaction with human fibroblast HEL cells.
• To determine the growth kinetics of M. xenopi within amoebal and human cells.

Main Methods:

• Light, electronic, and confocal microscopy were used for visualization.
• Light Cycler was employed to measure DNA ratios for quantifying growth.
• Amoebal encystment and germination were assessed to evaluate M. xenopi survival.

Main Results:

• M. xenopi was observed within both A. polyphaga and HEL cells.
• Intra-amoebal M. xenopi exhibited a 5-day doubling time; intracellular M. xenopi in HEL cells had a 10-day doubling time.
• M. xenopi survived amoebal encystment and germination, indicating resilience.

Conclusions:

• M. xenopi acts as a facultative intra-amoebal and intracellular pathogen.
• The ability of M. xenopi to survive within amoebae and human cells has significant public health implications.
• Testing for intra-amoebal M. xenopi is recommended for effective hospital water system decontamination.