Survival and Dormancy of Mycobacterium avium subsp. paratuberculosis in theEnvironment

Abstract

The survival of Mycobacterium avium subsp. paratuberculosis was studied by culture of fecal material sampled at intervals for up to 117 weeks from soil and grass in pasture plots and boxes. Survival for up to 55 weeks was observed in a dry fully shaded environment, with much shorter survival times in unshaded locations. Moisture and application of lime to soil did not affect survival. UV radiation was an unlikely factor, but infrared wavelengths leading to diurnal temperature flux may be the significant detrimental component that is correlated with lack of shade. The organism survived for up to 24 weeks on grass that germinated through infected fecal material applied to the soil surface in completely shaded boxes and for up to 9 weeks on grass in 70% shade. The observed patterns of recovery in three of four experiments and changes in viable counts were indicative of dormancy, a hitherto unreported property of this taxon. A dps-like genetic element and relA, which are involved in dormancy responses in other mycobacteria, are present in the M. avium subsp. paratuberculosis genome sequence, providing indirect evidence for the existence of physiological mechanisms enabling dormancy. However, survival of M. avium subsp. paratuberculosis in the environment is finite, consistent with its taxonomic description as an obligate parasite of animals.

Mycobacterium Avium Subspecies Paratuberculosis and Mycobacterium Avium Subsp. Avium Infections in a Tule Elk (Cervus Elaphus Nannodes) Herd

“…The difference in herd density is striking: at GIWA it is approximately 0.04 elk per hectare (140 elk on 3,450 ha), while herd density at PRNS is at least 0.38 elk per hectare (.400 elk on 1,040 ha; Manning et al, 2003). In addition to a higher herd density, continued herd infection with clinically affected animals and the subsequent increased environmental fecal contamination as well as specific environmental factors at PRNS, such as lower mean daily temperature (11.4 C vs. 16.1 C), higher annual mean precipitation (95.2 cm vs. 48.9 cm), and acidic soil (pH56.0 at PRNS), may facilitate survival of MAP in the environment (Gogan et al, 1989;Manning and Collins, 2001;Hoar, 2002;Whittington et al, 2004). Furthermore, elk at PRNS, unlike elk at GIWA, have shown clinical and biological evidence of copper deficiency, associated with decreased immunocompetency in ruminants, which may predispose the PRNS herd to clinical paratuberculosis (Gogan et al, 1989;Stabel and Spears, 1989).…”

Association of farm soil characteristics with ovine Johne's disease in Australia

“…In contrast, in a study conducted in the Netherlands, soil pH was not significantly different between seropositive and seronegative dairy cattle herds (Muskens et al, 2003). Moreover, the application of lime to the soil (to increase pH) appeared not to affect the survival of MAP in an Australian field trial (Whittington et al, 2004). Apart from soil iron content and pH, soil type was also reported to affect the survival of MAP, and hence the distribution of JD by some (Reviriego et al, 2000;Ward and Perez, 2004) but not by others (Turnquist et al, 1991).…”

“…Organic carbon, an indicator of soil organic matter content (Baldock and Skjemstad, 1999) might favour the survival of MAP, either directly by providing essential nutrients for its continued existence outside the biological host or indirectly by increasing pasture growth and thus shading which is reported to be favourable for MAP survival (Whittington et al, 2004). Organic matter also increases the water holding capacity of soil (Krull et al, 2004) but soil moisture has not yet been demonstrated to influence survival of MAP (Whittington et al, 2004). Regardless of the uncertainty about moisture, MAP would be available in greater numbers to the animals grazing on soils with a higher organic matter content.…”

“…However, at low pH, the solubility of iron increases, which enhances the ability of MAP to uptake iron (Johnson-Ifearulundu and Kaneene, 1999) and therefore encourages its survival outside its biological host. On the other hand, MAP is an obligate pathogen and its period of survival in the external environment is finite (Whittington et al, 2004). This creates some uncertainties about the impact of soil pH and iron content on MAP survival.…”

NlpC/P60 domain‐containing proteins of Mycobacterium avium subspecies paratuberculosis that differentially bind and hydrolyze peptidoglycan

“…The high lipid content and heavy cross-linking of these layers in the cell wall is thought to enable mycobacteria to resist antibiotics, UV exposure, heat treatment, and other environmental insults. [7][8][9][10] Proteins containing the NlpC/P60 superfamily domain (pfam00877) are important in bacterial physiology 11 and virulence. 12,13 A Mycobacterium tuberculosis gene, Rv2190c, encodes an NlpC/P60 protein that is required for virulence in the mouse model of TB and was shown to be immunogenic in the context of infection.…”