The fate of Helicobacter pylori phagocytized by Acanthamoeba polyphaga demonstrated by fluorescent in situ hybridization and quantitative polymerization chain reaction tests.

Helicobacter pylori able to express green fluorescent protein, as well as an ATCC strain, and a clinical isolate of this pathogen were evaluated for their ability to survive predation by Acanthamoeba polyphaga. Ingestion was evaluated by microscopic observation of the GFP-H. pylori and BacLight™-stained cells. Following phagocytosis, the fate of cells was assessed by fluorescent in situ hybridization with an oligonucleotide targeting H. pylori 16S rRNA and by quantitative-polymerase chain reaction (qPCR) tests with primers to 16S rDNA. Fluorescent in situ hybridization tests were inconclusive with only a small percentage of amoebae apparently containing active intracellular H. pylori. Furthermore, no increase in bacterial cells was detected by qPCR. Additional research is required to elucidate the mechanisms by which amoebae phagocytize this important bacterial pathogen.