Incubation Period
MAP is a very slowly growing mycobacterium; generation times in liquid media range from
1.3 to 4.4 days and are inversely proportional to the inoculum size (Lambrecht et al., 1988; Kim et al., 2002; Elguezabal et al., 2011).
The reasons for the very slow rate of growth of MAP compared with its close relative M. avium subsp. hominissuis are unclear (Bannantine et al., 2003). When grown on the most suitable media, colonies of MAP typically do not appear for several weeks and sometimes not for several months. Incubation periods of 12-20 weeks are typically specified for solid media before negative culture results are reported from livestock. Occasionally, extremely long incubation periods such as 9 months on HEYM have been reported in veterinary studies (Salgado et al., 2009), raising a question about the suitability of the chosen culture protocol. Growth in liquid media is more rapid than on solid media (Damato and Collins, 1990; Schwalm et al., 2018), and incubation is usually terminated after 8-12 weeks. In optimal liquid media, differences in growth rate associated with the C or S genotype of MAP were minor, but there can be an influence of the background source of the bacteria (which can be correlated with the decontamination protocol applied to them) because MAP-S isolates from sheep faeces and soil grew more slowly than those from sheep tissues and subcultures (Reddacliff et al., 2003a), while isolates of different genotype grew more slowly from sheep than from other ruminant hosts (Abendano et al., 2012). Furthermore, isolates from sheep with pauci- bacillary disease grew more slowly than those from sheep with multibacillary disease, suggesting some growth inhibition in the former (Reddacliff et al., 2003a). This was analogous to the longer generation time and delayed18.11
More medical literature on Medic.Studio
More on the topic Incubation Period:
-
Infectious diseases -
Internal diseases -
Obstetrics and Gynaecology -
Pediatrics -
Veterinary medicine -
-
Conflictology -
Ecology -
Economy -
Finance -
History -
Law -
Medicine -
Philosophy -
Religious studies -