Viridans Group
Enterococcus
(1)
Rhodococcus equi
Corynebacterium
Anaerobic
Bacteroides
No growth
No. of horses
4
3
1
13
40
100%
Chloramphenicol
94.7%
Amikacin 100%
?
?
-
-
-
1
1
20
40
Metronidazole
Metronidazole
-
Schneider demonstrated that the combination of Penicillin G and Amikacin were
theoretically the most effective antibiotics for treating the widest range of possible
bacterial species in joint sepsis. Due to the resistance displayed by Streptococcus
spp. Viridans Group isolates and Acinetobacillus sp. isolates, chloramphenicol was
suggested as an initial thumb-suck antibiotic for treatment, after which the
combination of Penicillin G and Amikacin could be used to cure the septic arthritis
completely. The antibiotic sensitivity results obtained by the WDL corresponded to
Schneider’s suggestions to a large degree.
According to Schneider (1998), septicaemia was the most common cause of septic
arthritis in the foals included in his paper. In my opinion, foal joint sepsis is very
poorly understood. It is a possibility that 1) bacterial biofilms play an important role in
cartilage infections, or 2) that automated immune responses are responsible for
‘septic arthritis’ to some degree in horses.
References:
Aharonson-Raz, K., A. Steinman, V. Bumbarov, S. Maan, N.S. Maan, K. Nomikou, C. Batten, C. Potgieter, Y. Gottlieb, P.
Mertens, and E. Klement. 2011. Isolation and phylogenetic grouping of equine encephalosis virus in Israel. Emerging Infectious
Diseases 17:1883-1886.
Bailey, C.S., M.L. Macpherson, M.A. Pozor, M.H. Troedsson, S. Benson, S. Giquere, L.C. Sanchez, M.M. Leblanc, and T.W.
Vickroy. 2010. Treatment efficacy of trimethoprim sulfamethoxazole, pentoxifylline and altrenogest in experimentally induced
equine placentitis. Theriogenology 74(3):402-412.
Erasmus, B.J., T.F. Adelaar, J.D. Smit, G. Lecatsas, and T. Toms. 1970. The isolation and characterization of equine
encephalosis virus. Bulletin Office lnternational des Epizooties 74:781-789.
Erol, E., S.F. Sells, N.M. Williams, L. Kennedy, S.J. Locke, D.P. Labeda, J.M. Donahue, and C.N. Carter. 2012. An investigation
of a recent outbreak of nocardioform placentitis caused abortions in horses. Veterinary Microbiology 158(3-4):425-430
Howell, P.G., J.P. Nurton, D. Nel, C.W. Lourens and A.J. Guthrie. 2008. Prevalence of serotype specific antibody to equine
encephalosis virus in Thoroughbred yearlings in South Africa (1999–2004). Onderstepoort Journal of Veterinary Research
75:153-161.
Schneider, R.K. 1998. Common bacteria encountered in septic arthritis. AAEP Proceedings 44:152-158.
Van Niekerk, M., M. Freeman, J. T. Paweska, P. G. Howell, A. J. Guthrie, A. C. Potgieter, V. van Staden and H. Huismans.
2003. Variation in the NS3 gene and protein in South African isolates of bluetongue and equine encephalosis viruses. Journal
of General Virology 84:581-590.
Viljoen, G.J., and H. Huismans. 1989. The characterisation of equine encephalosis virus and the development of genomic
probes. Journal of Genetic Virology 70:2007-2015.
Proceedings
of
the
South
African
Equine
Veterinary
Association
Congress
2016
266