Characterization of Micrococcaceae isolated from post mortem examined pigs

The investigation comprised 170 cases of infections due to Micrococcaceae among post mortem examined pigs that died during the preweaning period. The incidence was 3.1 promille of the live-born pigs. The infection was most frequent among pigs less than 4 weeks of age (Table I). ACute and subacute generalized infections occurred in 43.5% of the cases (Table II), and exudative epidermitis was the cause of death in 23.5%. In the remaining 32.9% of the cases, the post mortem findings included a variety of debilitating conditions, such as undersize, malformation, starvation or traumata. In all 248 strains of Micrococcaceae were isolated. A preliminary differentiation revealed 41.5% of the strains as Staphylococcus aureus and 34.5% as S. epidermidis and 22.6% as Micrococcus (Table III). A further characterization on 43 of the strains was performed (Table IV and V). Totally 19 different fermentation pattern were observed. In Table IV the strains are grouped into six groups. Fourteen strains were identified as S. aureus and 15 strains as S. epidermidis biotype 2, s. S. hyicus (Table VI). The distribution of the non-haemolytic strains according to biotypes is shown (Table VII). By this grouping, the 15 S. hyicus strains were designated type III B. It is concluded that various staphylococci may be isolated in pure culture from different pathological lesions in preweaned pigs. Biochemical characterization of the strains showed that part of the strains could not be classified by the previously described grouping systems.