Assessment of yeast Saccharomyces cerevisiae component binding to Mycobacterium avium subspecies paratuberculosis using bovine epithelial cells.

BACKGROUND: Since yeast Saccharomyces cerevisiae and its components are being used for the prevention and treatment of enteric diseases in different species, they may also be useful for preventing Johne's disease, a chronic inflammatory bowel disease of ruminants caused by Mycobacterium avium spp. paratuberculosis (MAP). This study aimed to identify potential yeast derivatives that may be used to help prevent MAP infection. The adherence of mCherry-labeled MAP to bovine mammary epithelial cell line (MAC-T cells) and bovine primary epithelial cells (BECs) co-cultured with yeast cell wall components (CWCs) from four different yeast strains (A, B, C and D) and two forms of dead yeast from strain A was investigated. RESULTS: The CWCs from all four yeast strains and the other two forms of dead yeast from strain A reduced MAP adhesion to MAC-T cells and BECs in a concentration-dependent manner after 6-h of exposure, with the dead yeast having the greatest effect. CONCLUSIONS: The following in vitro binding studies suggest that dead yeast and its' CWCs may be useful for reducing risk of MAP infection.

Microscopic Review of Nasopharyngeal Swabs as a Means of Benchside Quality Assurance.

OBJECTIVE: Nasopharyngeal swabs (NPS) are the collection modality of choice for reverse-transcription polymerase chain reaction (RT-PCR) multiplex array for respiratory viruses. NPS gather both extracellular material and human respiratory epithelial cells and, when used with RT-PCR, have reliable sensitivity for detection of viral infection. GOALS: At our institution, we identified a 1.7% re-order rate within 7-days for NPS destined for RT-PCR respiratory pathogen multiplex, which we hypothesize may be due in part to low confidence in adequate collection. We sought an inexpensive and accessible strategy for benchside quality assurance of NPS adequacy by observing microscopic content of viral transport media. PROCEDURE: For eight-hundred one NPS samples collected during routine clinical practice in November 2019, aliquots of viral transport media were air-dried and safranin-stained on glass slides under a fume hood. We then counted morphologically distinct ciliated columnar epithelial cells (CCEs), which are prevalent in the nasopharynx. RESULTS: Twenty percent of samples negative for respiratory pathogens by RT-PCR (BioFire FilmArray RP2, Cepheid GeneXpert) had no CCEs, while just seven percent of positive samples had no CCEs. Pearson's Chi-squared test was used to compare presence of CCEs between samples that were positive and negative for respiratory pathogens by RT-PCR (p=1.6×10-36). CONCLUSION: We posit that samples without identifiable CCEs have a greater likelihood of inadequate collection. The basic, benchside protocol that we describe here demonstrates potential to reduce unnecessary re-testing when deployed to confirm negative tests despite high clinical suspicion: a strategy which may help conserve NPS reagents.

Effect of Penicillium mycotoxins on the cytokine gene expression, reactive oxygen species production, and phagocytosis of bovine macrophage (BoMacs) function.

Bovine macrophages (BoMacs) were exposed to the following Penicillium mycotoxins (PM): citrinin (CIT), ochratoxin A (OTA), patulin (PAT), mycophenolic acid (MPA) and penicillic acid (PA). PM exposure at the concentration that inhibits proliferation by 25% (IC25) differentially for 24h altered the gene expression of various cytokines. OTA significantly induced IL-1α expression (p<0.05), while the expression of IL-6 was suppressed (p<0.01). MPA significantly induced the expression of IL-1α (p<0.05) and reduced the expression of IL-12α (p<0.01) and IL-10 (p<0.01). PAT significantly suppressed the expression of IL-23 (p<0.01), IL-10 (p<0.05) and TGF-ß (p<0.05). Some PMs also affected reactive oxygen species (ROS) and phagocytosis of Mycobacterium avium ssp. Paratuberculosis (MAP) at higher concentrations. PAT and PA for example, significantly decreased the percent phagocytosis of MAP at 5.0 (p<0.01) and 15.6 µM (p<0.01), respectively, but only PA significantly suppressed PAM-3-stimulated ROS production at 62.5 (p<0.05) and 250.0 µM (p<0.01). OTA significantly increased the percent phagocytosis of MAP at 6.3 (p<0.05) and 12.5 µM (p<0.01). These findings suggest that exposure to sub-lethal concentrations of PMs can affect macrophage function, which could affect immunoregulation and innate disease resistance to pathogens.