Characterization of Clostridium difficile isolates from foals with diarrhea: 28 cases (1993-1997).
OBJECTIVE
To determine molecular characteristics of Clostridium difficile isolates from foals with diarrhea and identify clinical abnormalities in affected foals.


METHODS
Retrospective study.


METHODS
28 foals with C difficile-associated diarrhea.


METHODS
Toxigenicity, molecular fingerprinting, and antibiotic susceptibility patterns were determined. Information on signalment, clinical findings, results of clinicopathologic testing, whether antimicrobials had been administered prior to development of diarrhea, and outcome was obtained from the medical records.


RESULTS
Twenty-three (82%) foals survived. Toxin A and B gene sequences were detected in isolates from 24 of 27 foals, whereas the toxin B gene alone was detected in the isolate from 1 foal. Results of an ELISA for toxin A were positive for fecal samples from only 8 of 20 (40%) foals. Ten of 23 (43%) isolates were resistant to metronidazole. Molecular fingerprinting revealed marked heterogeneity among isolates, except for the metronidazole-resistant isolates. Sixteen foals had tachypnea. Hematologic abnormalities were indicative of inflammation. Common serum biochemical abnormalities included metabolic acidosis, hyponatremia, hypocalcemia, azotemia, hypoproteinemia, hyperglycemia, and high enzyme activities. Passive transfer of maternal antibodies was adequate in all 12 foals evaluated.


CONCLUSIONS
Results suggest that a large percentage of C difficile isolates from foals with diarrhea will have the toxin A and B gene sequences. Because of the possibility that isolates will be resistant to metronidazole, susceptibility testing is warranted. Clostridium difficile isolates from foals may have a substantial amount of molecular heterogeneity. Clinical and hematologic findings in affected foals are similar to those for foals with diarrhea caused by other pathogens.
Magdesian
K Gary
KG
Department of Medicine and Epidemiology, Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Hirsh
Dwight C
DC
Jang
Spencer S
SS
Hansen
Lori M
LM
Madigan
John E
JE
D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D016360:Clostridioides difficile / Q000145:classification / Q000187:drug effects / Q000502:physiology; D003015:Clostridium Infections / Q000382:microbiology / Q000662:veterinary*; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary*; D024881:Drug Resistance, Bacterial; D004768:Enterotoxins / Q000032:analysis / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005243:Feces / Q000737:chemistry; D005260:Female; D006734:Horse Diseases / Q000382:microbiology*; D006736:Horses; D008297:Male; D008795:Metronidazole / Q000627:therapeutic use; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012189:Retrospective Studies
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile; D008795:Metronidazole