PCR

Background: The distribution pattern of phase-variable genes varies from strain to strain and from region to region. The present study was carried out to investigate the distribution pattern of phase-variable genes within Pakistan-based Helicobacter pylori strains and to analyze and compare them with strains prevalent in other parts of the world.

Objective. To determine the presence of Mycobacterium avium subsp. paratuberculosis (MAP) using serological, microbiological, and molecular methods, to genotype MAP isolates, and to explore factors associated to MAP-seropositive status in a buffalo herd of the province of Antioquia (Colombia). Materials and methods. The study was carried out to test fecal and serum samples from 21 asymptomatic adult buffaloes using culture and ELISA tests. Suspicious culture isolates were confirmed by MAP-IS900-PCR (IS900-PCR). The positive DNA was retested using MAP-IS900-quantative PCR (IS900-qPCR), and then, sub-typed using techniques based on the detection of mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) and multilocus short sequence repeat (MLSSR). Results. At sampling, the average age of animals was 4.7 years, 90.5% (19/21) were females and 84.2% (16/19) were pregnant. The average body condition score was 4.2 (in a 1-to-5 scale). The average milk yield was 3.5 L/day/animal. No MAP-seropositive animals were detected. One dairy buffalo cow out of the 21 buffaloes was positive by fecal culture at week 6 of incubation and then confirmed by IS900-PCR. Sub-typing analysis revealed that the MAP isolate corresponded to the INMV 3 genotype by MIRU-VNTR. Conclusions. To the best of the author's knowledge, this is the first report of MAP diagnosis and isolation in Colombian buffaloes and the first time an INMV 3 MAP-profile is found in this species the country.