title: Conjunctival bacterial and fungal flora in healthy horses in the UK.
abstract: OBJECTIVE
  To describe the bacterial and fungal flora of the normal conjunctiva of horses in the UK; to determine the effect of horse age, sex, geographic location, and housing on this flora; and to determine the most appropriate antimicrobial drug(s) for prophylactic treatment of corneal ulcers.
  
  
  METHODS
  A total of 60 adult healthy horses were studied.
  
  
  METHODS
  Swabs of the conjunctiva were obtained from 60 horses housed in two locations within the UK. Specimens were cultured for aerobic bacteria and fungi, and sensitivity against six ophthalmic antimicrobials assessed. The effect of age, sex, location and housing on the frequency of microbial isolation was evaluated.
  
  
  RESULTS
  Fifty-four bacterial isolates, representing thirteen genera of bacteria were cultured from 31 (52%) horses. The most frequently isolated bacterial species was Acinetobacter sp (17/32 horses). The majority of isolates (28/54: 52%) were gram-positive. Three genera of fungi (Mucor, Absidia and Aspergillus spp) were isolated from eight (13%) horses. There was no significant effect of geographic location, sex, age or housing on frequency of microbial isolation. Horses from which gram-negative bacteria were isolated were significantly older than horses from which gram-positive bacteria were isolated. High efficacy (greater than 90% of isolates sensitive in vitro) was displayed by chloramphenicol, gentamicin and tetracycline.
  
  
  CONCLUSIONS
  The microbial species isolated are comparable with studies performed in other countries, although the frequency of Acinetobacter isolation was higher which may reflect a geographic difference. The topical antimicrobials gentamicin and chloramphenicol are appropriate first line antimicrobials for empirical treatment of corneal ulcers in the UK.
authors.affiliation: Equine Referral Hospital, Veterinary Clinical Science, Royal Veterinary College, Hawkshead Lane, North Mymms, Herts AL9 7TA, UK. ijohns@rvc.ac.uk
authors.forename: Imogen C
authors.initials: IC
authors.lastname: Johns
authors.forename: Katherine
authors.initials: K
authors.lastname: Baxter
authors.forename: Helen
authors.initials: H
authors.lastname: Booler
authors.forename: Charlotte
authors.initials: C
authors.lastname: Hicks
authors.forename: Nicola
authors.initials: N
authors.lastname: Menzies-Gow
mesh_terms: D000375:Aging; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000302:isolation & purification*; D003228:Conjunctiva / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D005260:Female; D005658:Fungi / Q000145:classification / Q000302:isolation & purification*; D006736:Horses / Q000382:microbiology*; D006799:Housing, Animal; D008297:Male; D012727:Sex Characteristics; D006113:United Kingdom
chemical_list: D000900:Anti-Bacterial Agents