Table 2.
Morphotypes | Morphology on BAC-agar plates | Species identification based on 16S rDNA sequencing | Ery resistance | Resistance determinant(s) |
---|---|---|---|---|
Mh | Small, glossy, grey, beta-haemolytic | Mannheimia haemolyticaa | – | – |
1 | Small/small-medium, round, glossy, white | S. epidermidis, S. cohnii, S. pasteuri, S. saprophyticus, S. sciuri | + | erm(C), erm(C), erm(C), ND, ND |
2 | Large, mucoid, semi-transparent, grey-white | Pasteurella multocida | – | – |
3 | Very small, dense, brown/pale, alpha-haemolytic | Streptococcus/Bacillus | + | ND |
4 | Medium/large, wrinkly, crusty, fluid-filled, beta-haemolytic | Bacillus licheniformis | + | ND |
5 | Medium/large, glossy, grey-white, mostly beta-haemolytic | Escherichia coli/Shigella | + | – |
6 | Medium/large, rough edges, flat, granular | Bacillus clausii/Bacillus spp. | + | ND |
7 | Small, glossy, grey/cream | Acinetobacter lwoffii, Acinetobacter spp. | + | ND |
8 | Small/medium, glossy, pale-yellow | Staphylococcus chromogenes | NA | ND |
9 | Small/medium, pale-yellow, concentric with concave center | Macrococcus caseolyticus | NA | ND |
10 | Medium, yellowish, concentric circles, very haemolytic, greenish | Bacillus pumilus | NA | ND |
U | Unique morphologies found occasionally | Klebsiella, Neisseria spp., Paenibacillus spp., uncultured bacteria | NA | ND |
Also confirmed by multiplex PCR assay (Alexander et al., 2008); NA, not available, as those morphology groups were less commonly found on BAC plates and not found on BAC+Ery plates; ND, not determined (no positives detected in PCRs with any of the tested macrolide primer sets, see Materials and Methods).