Survival ofMycobacterium aviumsubsp.paratuberculosisin the intermediate and final digestion products of biogas plants

Abstract

Aims: To evaluate the survival of Mycobacterium avium subsp. paratuberculosis (MAP) during anaerobic digestion (AD), we studied two different biogas plants loaded with manure and slurry from paratuberculosis-infected dairy herds. Methods and Results: Both plants were operating under mesophilic conditions, the first with a single digester and the second with a double digester. Mycobacterium avium subsp. paratuberculosis detection was performed by sampling each stage of the process, specifically the prefermenter, fermenter, liquid digestate and solid digestate stages, for 11 months. In both plants, MAP was isolated from the prefermenter stage. Only the final products, the solid and liquid digestates, of the one-stage plant showed viable MAP, while no viable MAP was detected in the digestates of the two-stage plant. Conclusions: Mycobacterium avium subsp. paratuberculosis showed a significant decrease during subsequent steps of the AD process, particularly in the two-stage plant. We suggest that the second digester maintained the digestate under anaerobic conditions for a longer period of time, thus reducing MAP survival and MAP load under the culture detection limit. Significance and Impact of the Study: Our data are unable to exclude the presence of MAP in the final products of the biogas plants, particularly those products from the single digester; therefore, the use of digestates as fertilizers is a real concern related to the possible environmental contamination with MAP. IntroductionMycobacterium avium subsp. paratuberculosis (MAP) is the aetiological agent of a chronic proliferative enteritis in ruminants known as paratuberculosis (PTB) or Johne's disease.In recent decades, PTB has been frequently linked with Crohn's disease in humans due to certain clinical similarities between these two enteric pathologies (Hermon-Taylor and Bull 2002); however, the role of MAP in Crohn's disease has not been definitively demonstrated (Chiodini et al. 2012;Sechi and Dow 2015). Furthermore, MAP has also been linked with other human diseases, such as type I diabetes, Hashimoto's thyroiditis, multiple sclerosis and others (Scanu et al. 2007;Sisto et al. 2010; Dow 2012;Frau et al. 2013;Waddell et al. 2015).Paratuberculosis is distributed worldwide in ruminants, and the prevalence of infected farms in countries with advanced animal husbandry is growing rapidly. In this regard, numerous investigations have reported its wide distribution in Europe (Nielsen and Toft 2009) and Italy (Pozzato et al. 2011), with herd prevalence estimates over 50% (Nielsen and Toft 2009).Animals are most frequently infected at a young age through the ingestion of faeces or contaminated feed, fodder, milk and colostrum (Sweeney 2011). The major 36

Systematic Assessment of Mycobacterium avium Subspecies Paratuberculosis Infections from 1911–2019: A Growth Analysis of Association with Human Autoimmune Diseases

“…Environmental sampling and assessment protocols for MAP detection has been developed [ 53 , 54 ]). Other recent, MAP studies related to environments include environmental detection of MAP in some matrices such as drylot pens, dairy herds’ paddock, milking facilities, anaerobic digestion of slurry from MAP-infected farm, manure storage, lactating cow surroundings, housing (freestall, loose housing, or tiestall), liquid manure and boot swabs [ 18 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ].…”

“…The role of anaerobic digestion on MAP reduction in manure emerged in the last two years [ 18 , 55 ]). The positive growth of MAP research in anaerobic digestion of animal manure and slurry ensured MAP reduction and improved the quality of digestates as biofertilizers for pasture and agricultural soils compared with untreated ones [ 18 , 55 ]).…”

“…The role of anaerobic digestion on MAP reduction in manure emerged in the last two years [ 18 , 55 ]). The positive growth of MAP research in anaerobic digestion of animal manure and slurry ensured MAP reduction and improved the quality of digestates as biofertilizers for pasture and agricultural soils compared with untreated ones [ 18 , 55 ]). A-two-stage anaerobic digestion system for biofertilizer production has been identified to improve final digestate qualities and reduce the risk of MAP contamination of the environment and agricultural produce compared to a single-stage digester [ 55 ].…”

“…In addition, agricultural application of solid or liquid digestates of anaerobic processes such as biogas plants loaded with slurry and animal faeces from MAP-infected dairy farms pose further risks of spreading infection. The pathogen has been shown to survive the operational conditions of biogas plants [ 18 ]. Also, recent isolation of MAP from free-living environmental amoebae (FLEA) such as the poorly described Rosculus genus called for concern on environmental health as FLEA are protozoa found in both aquatic and soil milieus, not only harbour the pathogen but are also capable of intracellular propagation of MAP [ 19 , 20 ]).…”

Recombinant fusion protein of Heparin-Binding Hemagglutinin Adhesin and Fibronectin Attachment Protein (rHBHA-FAP) of Mycobacterium avium subsp. paratuberculosis elicits a strong gamma interferon response in peripheral blood mononuclear cell culture

“…Also, MAP may shed through infected animal’s feces and survive in the environment for a long period. Then the exposure of human to a contaminated environment is a potential risk [6]. There are studies about the association of MAP with Crohn’s disease [7], sarcoidosis and Blau syndrome [8], type 1 diabetes [9], Hashimoto’s thyroiditis [10], and multiple sclerosis (MS) [11].…”