Campylobacter magnus sp. nov., isolated from caecal contents of domestic pigs (Sus scrofa domesticus).

During the 2021 European Food Safety Authority coordinated harmonized monitoring of antimicrobial resistance in Campylobacter species in Slovenia, five Campylobacter-like strains were cultured from caeca of a total of 104 domestic pigs that could not be identified using the standard-prescribed biochemical tests or MALDI-TOF MS. The isolates were obtained using the standard ISO 10272 procedure for the isolation of thermotolerant Campylobacter with prolonged cultivation time. Small Campylobacter-like colonies were observed on mCCDA and CASA agar plates after 2-4 days of incubation; dark-field microscopy revealed relatively big spirilli-shaped bacteria exhibiting characteristic Campylobacter-like motility. The cells were 1.5-3 µm long and 0.5-0.7 µm wide, Gram-negative, oxidase-positive and catalase-positive. MALDI-TOF mass spectra were distinctive and consistent, but with low MALDI-TOF MS log scores and the closest matches being those of Campylobacter hyointestinalis and Campylobacter fetus. All five strains underwent whole-genome sequencing. Analysis of 16S rRNA gene sequences revealed that the isolates were most similar (98.3-98.4 % identity) to Campylobacter lanienae. Pairwise average nucleotide identity (ANI) values revealed that the five studied strains shared pairwise ANI of 96.2-96.5 % but were clearly distinct from the previously described Campylobacter species (ANI ≤72.8 %). The core genome-based phylogeny confirmed that the new strains form a distinct and well-supported clade within the genus Campylobacter. The conducted polyphasic taxonomic analysis confirmed that the five strains represent a novel Campylobacter species for which the name Campylobacter magnus sp. nov. is suggested, with strain 46386T (=DSM 115534T=CCUG 76865T) as the type strain.

Helicobacter colisuis sp. nov., isolated from caecal contents of domestic pigs (Sus scrofa domesticus).

Seven Helicobacter-like isolates were cultured from caecal contents of 100 domestic pigs (Sus scrofa domesticus) sampled as part of the EFSA-coordinated harmonized monitoring of antimicrobial resistance in Campylobacter sp. in 2015. The bacteria were isolated using the standard ISO 10272 procedure for the isolation of thermotolerant Campylobacter with extended incubation time and formed small, grey, moist and flat colonies with a metallic sheen (small Campylobacter-like colonies) on modified Charcoal-Cefoperazone-Deoxycholate Agar (mCCDA) and Skirow agar plates. Morphologically, the bacterial cells were spirilli-shaped and highly motile, 1-2 µm long and ≤0.5 µm wide, Gram-negative, oxidase-positive and catalase-positive. They could not be identified using the standard-prescribed biochemical tests and had uniform, unique and reproducible MALDI-TOF mass spectra that most closely matched those of Helicobacter pullorum. Three strains (11154-15T, 14348-15 and 16470-15) underwent whole-genome sequencing. Analysis of 16S rRNA gene sequences revealed a high similarity (≥99.8 % identity) to Helicobacter canadensis. Pairwise average nucleotide identity (ANI) values revealed that the three studied strains were closely related (ANI ≥98.9 %), but distinct from the previously described Helicobacter species (ANI ≤90.6 %). The core genome-based phylogeny confirmed that the new strains form a distinct clade most closely related to H. canadensis. The conducted polyphasic taxonomic analysis confirmed that the three strains represent a novel Helicobacter species for which the name Helicobacter colisuis sp. nov. is suggested, with strain 11154-15T (= DSM 113688T = CCUG 76053T) as the type strain.

Isolation and characterisation of Mycobacterium avium and Rhodococcus equi from granulomatous lesions of swine lymph nodes in Slovenia.

Granulomatous lesions in bovine and especially swine lymph nodes are still frequently observed during routine veterinary meat inspections even though Mycobacterium bovis infections are no longer detected in domestic animals in Slovenia. Different lymph nodes of pigs (n = 260) were investigated using classical bacteriological and molecular methods. Mycobacterium avium alone was isolated in 47.3% of pigs and in mixed infection with Rhodococcus equi in 3.9% of pigs. R. equi alone was isolated in 27.3% and in mixed infection with mycobacteria other than M. avium in 1.5% of pigs. A total of 133 M. avium isolates were typed using the IS1245, IS901 and FR300 PCR. Almost two thirds (60.9%) of isolates belonged to M. avium hominissuis (IS901-, IS1245+ genotype), 33.8% of isolates belonged to M. avium avium (IS901+, IS1245+ genotype) and 5.3% of isolates remained non-typed. Fifty out of 85 R. equi isolates were tested for the virulence-associated antigens (VapA and VapB). Nearly two thirds (60.0%) were positive for VapB while all the other isolates were VapA- and VapB-negative.