Incubation time for Mycobacterium avium subsp. paratuberculosis in liquid medium (M7H9C) from bovine clinical samples

ROMERO MA; ALVARADO PINEDO, F.; MOYANO RD; SANTANGELO MP; TRAVERIA GE

Nantes

Congreso; 13th International Colloquium on Paratuberculosis (ICP 2016); 2016

International asociation for paratuberculosis

Paratuberculosis is a chronic devastating ileocolitis of ruminant caused by Mycobacteriumavium subsp paratuberculosis (Map), with unthrifty and diarrhea as the main clinical signs in cattle. Microbiological culture is the gold standard test for paratuberculosis, liquid medium is recognized as having better performance than solid Herrold?s egg yolk medium, here we present the incubation time to detect Map in clinical samples coming from naturally infected herds. The liquid culture medium was prepared as previously described except for the addition of a small amount of agar, the presence of acid fast bacilli (AFB) with Ziehl Neelsen method was used as growth indicator at weekly interval. Earlier cultures were obtained from the mucosa of necropsied animals with advanced clinical signs, essentially gut mucosa were positive for AFB 14 days after incubation, followed by mesenteric lymph node and fecal samples. Prolonged incubation times were needed in samples coming from young asymptomatic animals aged 14 months in this group AFB were observed after a period of 1,5 months, probably representing a reduced number of Map present in clinical samples.