Normal bacterial conjunctival flora in the Huacaya alpaca (Vicugna pacos)

Objective To describe the bacterial flora of the normal conjunctiva of Huacaya alpacas (Vicugna pacos) and to determine the effect of age and gender on this flora. Animals studied Fifty Huacaya alpacas. Procedures After a complete ophthalmic examination, conjunctival swabs were obtained from both eyes and cultured for aerobic and anaerobic bacteria. Logistic and Poisson regression analyses were used to evaluate the effect of age and gender on bacterial isolation. Results Four animals were excluded because of signs of external ocular disease. Of the remaining 46 alpacas, bacteria were recovered from 96.7% (89/92) of the eyes. A total of 190 bacterial isolates were cultured with a mean of 2.1 bacterial isolates per eye. The majority of isolates (70%) were Gram-positive. Staphylococcus xylosus (44/190: 23.2%) predominated, followed by viridans streptococci (32/190: 16.8%) and Pantoea agglomerans (24/190: 12.6%). Other frequently isolated bacteria included Rothia mucilaginosa (12/190: 6.3%), Staphylococcus equorum (12/190: 6.3%), Bacillus species (9/190: 4.7%), Moraxella ovis (9/190: 4.7%), and Moraxella catarrhalis (6/190: 3.2%). Statistical analysis showed that alpacas harboring viridans streptococci and Moraxella species were significantly younger. Gender did not significantly affect type of bacterial isolation. There appeared to be no significant effect of age or gender on number of bacteria isolated. Conclusions Gram-positive aerobes were most commonly cultured, with S. xylosus and viridans streptococci predominating. To the best of the authors' knowledge, this is the first report describing the presence of Moraxella species in the healthy conjunctival sac of alpacas. Alpacas harboring viridans streptococci and Moraxella species were significantly younger.