Classification of Actinobacillus spp isolates from horses involved in mare reproductive loss syndrome.
OBJECTIVE
To identify Actinobacillus spp isolates recovered from fetuses and pericardial fluid from horses affected with mare reproductive loss syndrome (MRLS) and determine whether these bacterial species are the same as those isolated from clinically normal horses.


METHODS
Isolates of actinobacilli recovered from 18 horses with pericarditis and 109 fetuses aborted by mares affected by MRLS. Procedures-Actinobacillus spp isolates were identified to the level of species or subspecies by use of conventional phenotypic tests and biochemical and enzyme test kits. The 16S rRNA gene from selected isolates was amplified, purified, and sequenced. Sequence data were compared with sequence data for actinobacilli in GenBank.


RESULTS
Of the 109 isolates obtained from fetuses, 14 were Actinobacillus equuli subsp equuli, 65 were A equuli subsp haemolyticus, 28 were Bisgaard taxon 10-like bacterium, and 2 were Actinobacillus genomospecies 1. Of the 18 isolates from horses with pericarditis, 4 were A equuli subsp equuli, 13 were A equuli subsp haemolyticus, and 1 was Bisgaard taxon 10-like bacterium. Comparisons with published data and GenBank data revealed that the isolates recovered from horses with MRLS were the same as those isolated from the oral cavity or alimentary tract of healthy horses.


CONCLUSIONS
Actinobacillus spp isolates recovered from fetuses and pericardial fluid samples of horses affected by MRLS in 2001 to 2003 were identical to Actinobacillus spp found in the oral cavity and alimentary tracts of healthy horses.
Donahue
James M
JM
Livestock Disease Diagnostic Center, College of Agriculture, University of Kentucky, Lexington, 40511-4125, USA.
Sells
Stephen F
SF
Bolin
David C
DC
D037881:Aborted Fetus / Q000382:microbiology; D000034:Abortion, Veterinary / Q000382:microbiology*; D000188:Actinobacillus / Q000145:classification* / Q000235:genetics; D000818:Animals; D005260:Female; D006734:Horse Diseases / Q000382:microbiology*; D006736:Horses; D010490:Pericardial Effusion / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics
D012336:RNA, Ribosomal, 16S