Comparison of Isolation Frequency of
Mycobacterium avium subspecies paratuberculosis from Different
Types of Samples
Mohammad Seyyedin1*,
Taghi Zahraei2, Mohsen Fathi Najafi1
Department of Veterinary Research and Biotechnology, Razi Vaccine
and Serum Research Institute, Mashhad, Iran
*Corresponding author: m.seyyedin@rvsri.ir
Abstract
Samples of feces, manure and milk of 137 dairy cattle herds were collected from
different parts of Razavi Khorasan
province
of Iran. These herds were
suspected of having Johne's disease. There were 505 faecal and manure samples
and 148 raw milk samples prepared from cows affected by the clinical form of
Johne's disease (n = 12), bulk milk-transporters (n = 67) and farm bulk milk
tanks (n = 69). The samples were cultured on Herrold’s egg yolk medium with and
without mycobactin J. The samples in which the bacteria could merely grow on
Herrold’s media containing mycobactin J were considered to be positive.
Diagnostic test of M. paratuberculosis culture was positive in 29 out of
137 herds. Out of feces, manure and milk samples, 50 cases were found positive.
The number of bacterial colonies varied from 1 to 250. The frequency of positive
and negative fecal samples taken from cows with clinical signs (n=16) and
without clinical signs of Johne’s disease (n=363), 13(81.3%) and 15(4.1%) were positive,
respectively. The difference in positive samples between two groups of manure
samples taken from outdoors and indoors of farms was non significant. The
difference in positive cases among three different types of milk samples was
significant, but these differences between two groups of bulk milk-transporters
and farm bulk milk tanks were non significant. Using Fisher exact test, the comparison between fecal and
raw milk samples from cows with clinical signs showed non significant difference between two groups, but these
differences based on the number of positive tubes and their colonies were
significant.