A study was carried out to define the relationship between the N-acetyl- β -D-glucosaminidase(NAGase) levels and isolated pathogenic bacteria in 379 quarter fore milk of mastitis suspected samples collected in this clinics. All samples were tested the NAGase, California mastitis test(CMT), Somatic cell count(SCC) and bacterial culture.
Except 111 from 379 samples, 268 bacteria-positive quarter fore milk samples were classified into the latent and mastitis infection group by SCC(500,000 cells per ㎖), and the mean NAGase levels(nmol/min/㎖) of each isolated pathogen in mastitis infection group were Staphylococcus aureus 3.067, Coagulase-negative staphylococci 4.083, Staphylococcus aureus 3.594, Str. uberis 3.513, Str. dysgalactiae 1.640, E coli 4.441 and gram negative rods 4.560, respectively. Most of the relationship between mean SCC and NAGase in each pathogen group were highly significant using a student t test(p<0.05).
When the mastitis pathogens were classified into minor(Coagulase-negative staphylococci, Corynebacterium sp.) and major pathogen group(Staphylococcus aureus, Streptococcus agalactiae, Str. uberis, Slr. dysgalactiae, gram negative rods), the NAGase levels were higher at major than minor pathogen group. On the other hand, when the mastitis milk samples were classified by SCC(500,000 cells per ㎖) and by the presence of pathogen(IDF scheme), the NAGase levels were also higher at the mastitis than latent infection. The possibility of combining SCC and NAGase data in order to give the more difinitive diagnosis is discussed.
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