Experimentally induced coliform mastitis: inoculation of udders with serum-sensitive and serum-resistant organisms
Carroll, E.J.; Jain, N.C.; Schalm, O.W.; Lasmanis, J.
American Journal of Veterinary Research 34(9): 1143-1146
1973
ISSN/ISBN: 0002-9645 PMID: 4583644 Document Number: 65482
This experiment was designed to confirm the concept that resistance of an organism to bovine serum may be related to its virulence in the mammary gland [see DSA 32, 1716]. 15 normal lactating quarters of cows infused with serum-resistant [SR] Aerobacter aerogenes 2414-1, Klebsiella K-644, and Escherichia coli 12795 [see DSA 33, 4726] all developed acute or peracute mastitis ; 11 quarters had received less than or equal to 600 colony forming units (cfu) and 4 had received >105 (cfu). Of 9 other SR-inoculated quarters, with a polymorphonuclear neutrophil leucocyte (PMN) count of >300 000/ml 0-h strippings, 5 showed no response and 4 developed acute to peracute mastitis. Serum-sensitive (SS) A. aerogenes 2414-2, Klebsiella K6, E. coli S-16 and E. coli Lilly infused into 16 normal lactating quarters (13 received <3000 cfu and 3>106 cfu) only produced mild transient inflammation in 4 quarters, 3 of which had been given 106 cfu. The resulting inflammation was considered to be caused mainly by the physical presence alone of endotoxin in the initial dose. Of 6 SS-inoculated quarters with 0-h PMN count of >300 000/ml, 4 did not respond and 2 (both of which had received >106 cfu) responded with milk transient mastitis. Leucocyte-free quarters were equally susceptible to mastitis caused by SR organisms, and were not susceptible to mastitis caused by SS organisms, regardless of whether the quarters had been previously exposed to the same or to different strains of bacteria.