Ecology and genomic features of infection with Mycobacterium avium subspecies paratuberculosis in Egypt.

Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) is the causative agent of paratuberculosis, or Johne's disease, in cattle, with potential involvement in cases of Crohn's disease in humans. Johne's disease is found worldwide and is economically important for both beef and dairy industries. In an effort to characterize this important infection in Egypt, we analysed the ecological and genomic features of recent isolates of M. paratuberculosis. In this report, we examined 26 Holstein dairy herds distributed throughout Egypt, from 2010 to 2013. Using PCR analysis of faecal samples, we estimated a mean herd-level prevalence of 65.4 %, with animal-level infection that reached a mean of 13.6 % among animals suffering from diarrhoea. Whole genome sequencing of field isolates identified numerous single nucleotide polymorphisms among field isolates relative to the standard M. paratuberculosis K10 genome. Interestingly, the virulence of M. paratuberculosis isolates from Egypt revealed diverse virulence phenotypes in the murine model of paratuberculosis, with significant differences in tissue colonization, particularly during the chronic stage of infection. Overall, our analysis confirmed that Johne's disease is a newly identified problem in Egypt and indicated that M. paratuberculosis has potentially diverse genotypes that impact its virulence. Further ecological mapping and genomic analysis of M. paratuberculosis will enhance our understanding of the transmission and evolutionary dynamics of this pathogen under natural field conditions.

Investigation of biofilm forming ability in Staphylococci causing bovine mastitis using phenotypic and genotypic assays.

A total of 40 S. aureus and 68 coagulase negative Staphylococcus (CNS) isolates from bovine subclinical mastitis were investigated for their ability to form biofilm as one of the most important virulence factors.Using Congo Red Agar (CRA) method, 32.5%, 35%, and 32.5% of S. aureus strains were strong, intermediate, and negative biofilm producers, while in CNS the percentages were 29.5%, 42.6%, and 27.9%, respectively. By microtiter plate (MTP) method, 52.5%, 27.5%, and 20% of S. aureus isolates were strong, moderate, and weak biofilm producers, while in CNS the percentages were 44%, 30.9%, and 19.2%, respectively. Indian ink staining was used to detect the EPS layer of biofilm producers. All isolates were screened for presence of biofilm related genes, eno, icaA, icaD, and bap. In S. aureus isolates, the positive rates of eno, icaA, icaD, and bap genes were 75%, 15%, 62.5%, and 2.5% while in CNS were 92.6%, 5.9%, 47.1%, and 4.4%, respectively. The eno gene had the highest rate while the bap gene had the lowest rate. Presence of icaA and icaD genes was not always correlated with biofilm production. This study demonstrated high prevalence of Staphylococcus biofilm producers among bovine mastitis in Egypt. Therefore, attention must be paid toward implementation of new ways for effective treatment of such infections.