Replication and Long-Term Persistence of Bovine and Human Strains of Mycobacterium avium subsp. paratuberculosis within Acanthamoeba polyphaga

Abstract

Free-living protists are ubiquitous in the environment and form a potential reservoir for the persistence of animal and human pathogens. Mycobacterium avium subsp. paratuberculosis is the cause of Johne's disease, a systemic infection accompanied by chronic inflammation of the intestine that affects many animals, including primates. Most humans with Crohn's disease are infected with this chronic enteric pathogen. Subclinical infection with M. avium subsp. paratuberculosis is widespread in domestic livestock. Infected animals excrete large numbers of robust organisms into the environment, but little is known about their ability to replicate and persist in protists. In the present study we fed laboratory cultures of Acanthamoeba polyphaga with bovine and human strains of M. avium subsp. paratuberculosis. Real-time PCR showed that the numbers of the pathogens fell over the first 4 to 8 days and recovered by 12 to 16 days. Encystment of the amoebic cultures after 4 weeks resulted in a 2-log reduction in the level of M. avium subsp. paratuberculosis, which returned to the original level by 24 weeks. Extracts of resection samples of human gut from 39 patients undergoing abdominal surgery were fed to cultures of A. polyphaga. M. avium subsp. paratuberculosis detected by nested IS900 PCR with amplicon sequencing and visualized by IS900 in situ hybridization and auramine-rhodamine staining was found in cultures derived from 13 of the patients and was still present in the cultures after almost 4 years of incubation. Control cultures were negative. M. avium subsp. paratuberculosis has the potential for long-term persistence in environmental protists.

Mycobacterium aviumsubsp.paratuberculosisin Lake Catchments, in River Water Abstracted for Domestic Use, and in Effluent from Domestic Sewage Treatment Works: Diverse Opportunities for Environmental Cycling and Human Exposure

“…Recent research has shown that native M. avium subsp. paratuberculosis obtained directly from the infected human gut can survive and persist through cycles of encystment and trophozoite reactivation for years in Acanthamoeba polyphaga (52). STWs discharging into waters which also serve as sources of abstraction and domestic resupply establish the potential for human as well as animal strains of this multihost chronic enteric pathogen to cycle through human populations.…”

“…Under experimental conditions, we have found M. avium subsp. paratuberculosis from the human intestine surviving within Acanthamoeba polyphaga, even after 4 years of incubation with several cycles of encystment and trophozoite activation (52). M. avium subsp.…”

Mycobacterium avium ssp . paratuberculosis detection in animals, food, water and other sources or vehicles of human exposure: A scoping review of the existing evidence

“…We identified published evidence for M. paratuberculosis contamination of water and some foods prepared for human consumption (milk, dairy products and meat), but no evidence for other hypothesized foods such as produce and seafood was found. highlighted that M. paratuberculosis may be isolated from many species, but the contribution of nondomestic ruminant species to human exposure to M. paratuberculosis relative to domestic ruminants has not been closely examined (Mura et al, 2006;Carta et al, 2013). The global evidence reported in this ScR shows that although there are some regional differences, M. paratuberculosis is a global animal health problem, an agri-food problem and possibly a zoonotic public health issue (Waddell et al, 2015).…”

“…Other studies showed composting was ineffective at eliminating M. paratuberculosis (Tkachuk et al, 2013) and M. paratuberculosis can survive in a biogas plant for up to 6 months with DNA detectable by PCR for longer . In experimental challenge trials invertebrates were shown to be competent M. paratuberculosis hosts; protozoa (Whan et al, 2006) and nematodes (Lloyd et al, 2001) were shown to take up the organism and provide a host environment for M. paratuberculosis to survive and replicate; another study demonstrated persistence and replication within protists over 24 weeks (Mura et al, 2006).…”

Mycobacterium avium Subspecies paratuberculosis Infection in Cases of Irritable Bowel Syndrome and Comparison with Crohn's Disease and Johne's Disease: Common Neural and Immune Pathogenicities

“…paratuberculosis cells into the environment, and there are wildlife reservoirs (1). These robust pathogens can survive for a long time in the environment and within environmental protists (43,52). In some localities people are at risk of exposure from sources of environmental contamination (53,71).…”