Bacterial and fungal flora in healthy eyes of birds of prey.

Birds of prey are often affected with external ocular injuries that are routinely treated with antimicrobial agents used for small animals. The resident ocular bacterial and fungal flora is still unknown in birds of prey and this knowledge would be very useful in assessing the accuracy of treatments. In a study involving 65 raptors with healthy eyes, swabs were taken from both eyes to identify the resident bacterial and fungal flora. Fifty-five birds had a positive culture in one or both eyes. Both gram-positive and gram-negative organisms were isolated, with a predominance of Staphylococcus spp., which were found in 52.3% of cultures. Only two fungal species, Aspergillus spp. and Cladosporium spp. were found. The overall results of this study are similar to previous studies carried out in humans and other animals.     

Conjunctival fungal flora in healthy donkeys

OBJECTIVE: To identify and quantify ocular fungi from healthy donkeys living in the center of Italy. ANIMALS STUDIED: One hundred and two Amiata donkeys were examined. PROCEDURES: Conjunctival swabs from both eyes were seeded onto Sabouraud dextrose agar (SDA) and malt extract agar (MEA), and incubated at 25 degrees C over a 10-day period. Filamentous fungi identification was achieved to the genus level; yeast colonies were identified for macro-micromorphologic and physiological characteristics. RESULTS: Eighty-one donkeys out of 102 (79.4%) were positive for fungi; 47/102 (46.1%) had positive cultures from both eyes. Most frequently recovered fungal genera were Aspergillus spp., Penicillium spp., Cladosporium spp., Acremonium spp. Different fungal genera and/or species were recovered from the same donkey in 43 cases (42.1%). Yeasts were isolated from five subjects; the yeasts were never associated with molds. The number of colony forming units (CFU) ranged from 1 to 100. CONCLUSIONS: Aspergillus was the most commonly isolated fungal genus (33%). This result agrees with the findings of similar surveys carried out in horses. There was a remarkable presence of fungi and perfect forms. These observations may be explained by the optimal conditions for presence and development of fungi in the conjunctival fornix microenvironment in Amiata donkeys.     

Prevalence of ocular microorganisms in hospitalized and stabled horses

Microorganisms from normal eyes of hospitalized and stabled horses were identified, and the frequency of isolation was compared between the 2 groups. Using standard techniques, swab specimens from both eyes of 22 hospitalized horses and both eyes of 18 stabled horses were cultured for aerobic bacteria and fungi. Ninety-six aerobic bacteria and 57 fungi were isolated. The predominant bacterial isolates were gram-positive organisms, most of which belonged to the genera Corynebacterium, Bacillus, Staphylococcus, and Streptomyces. Gram-negative organisms comprised less than one-fourth of the bacterial isolates, with the genera Neisseria, Moraxella, and Acinetobacter being the most commonly isolated. Environmental fungi Cladosporium and Alternaria accounted for half of all fungal isolates. In only 5 horses were fungi isolated without accompanying isolation of bacteria. The frequency of isolation of fungi was higher (P less than 0.01) in stabled horses. For bacteria, the frequency of isolation was higher (P less than 0.08) in male horses. Results of susceptibility testing were recorded as the percentage of all isolates susceptible to a given antimicrobic drug. Bacterial isolates were highly susceptible (greater than or equal to 90%) to neomycin, polymixin B, gentamicin, and chloramphenicol. Overall, filamentous fungi had highest susceptibility to natamycin (97%). Miconazole was highly efficacious (100% susceptibility) against Fusarium and Aspergillus.     

Comparison of bacteriologic culture of blood and necropsy specimens for determining the cause of foal septicemia: 47 cases (1978-1987)

Diagnosis of bacterial septicemia was confirmed by results of bacteriologic culture of antemortem blood samples and/or necropsy specimens obtained from 47 foals up to 8 days old. Gram-negative bacteria were isolated from all 47 foals, and mixed infections with more than one organism were involved in 26 (55%). Escherichia coli, Actinobacillus spp, and Klebsiella pneumoniae were the most frequent isolates, infecting 55, 34, and 23% of foals, respectively. Gram-positive bacteria and anaerobic bacteria were isolated only from foals with mixed infections with gram-negative organisms. Clostridium perfringens was the only anaerobe isolated. In 38 (81%) of 47 foals with confirmed septicemia, blood samples were culture-positive. Thirty-two septicemic foals subsequently died, allowing a comparison to be made between the species of bacteria isolated by culture of blood with those recovered by culture of internal organs at necropsy. Blood failed to yield any gram-negative organisms in 12 (37.5%) of 32 foals from which a gram-negative pathogen was isolated at necropsy. Forty-three percent of the gram-negative bacteria, including 59% of the E coli, and 10% of the gram-positive bacteria found in septicemic foals at necropsy were not detected earlier by results of bacteriologic culture of blood.     

Conjunctival bacterial and fungal flora in healthy horses in the UK

Objectives 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. Animal studied A total of 60 adult healthy horses were studied. Procedure 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.     

Fungal flora of normal eyes of healthy horses from the State of Rio de Janeiro,Brazil

The conjunctival fungal flora of 32 adult horses with normal eyes (n = 64) from the State of Rio de Janeiro in Brazil was identified in the fall of 2000 using horses of different breeds, both genders and aged 5-19 years old. The culture samples were taken from the conjunctival sac of both eyes with a sterile cotton swab wetted with saline solution, seeded in Sabouraud's dextrose agar with chloramphenicol, and incubated for 5 days at an average temperature of 25 degrees C. The number of fungal colonies per eye varied between 0 and 250 colony forming units (CFUs). There were often differences in colony types between eyes of the same animal. Filamentous fungi of genera were isolated and identified in the following proportion of the total genera of fungal colonies isolated: Aspergillus (32.2%), Penicillium (25.8%), Scopulariopsis (15.9%), Trichoderma (11.2%), Cladosporium (5.6%), Mucor (2.1%), Syncephalastrum (2.1%), Eurotium (1.7%), Geotrichum (0.9%), Rhizopus (0.9%), Gliomastix (0.4%), Fusarium (0.4%), Staphylotrichum (0.4%) and Verticillium (0.4%). Yeast genera represented 9% of the total isolates. Over half the horses had at least one normal eye with either Aspergillus, Penicillium, Trichoderma or Scopulariopsis isolated, which is a departure from other studies of the normal horse eye.     

A survey of aerobic bacteria and fungi in the feces of healthy psittacine birds

Fecal samples from 61 clinically healthy psittacine birds of a wide variety of species were cultured for bacteria and fungi. The most common bacterial isolates were gram-positive bacilli, which were recovered from 60 of the 61 birds. These organisms included Lactobacillus, Bacillus, Corynebacterium, and Streptomyces. Gram-positive cocci, cultured from the feces of 21 of the birds, included Staphylococcus epidermidis, Streptococcus spp., Aerococcus spp., and Micrococcus spp. Only 6 of the 61 psittaciformes yielded gram-negative bacteria, with Escherichia coli being the most frequent isolate. Gram-negative bacilli were recovered from 4 of the 31 privately owned birds and 2 of the 30 petshop birds sampled. In addition to the bacteria, Candida albicans, Cryptococcus laurentii, and Aspergillus sp. were isolated from 13 fecal cultures. Candida albicans was isolated exclusively from 5 petshop birds. The number of birds yielding Corynebacterium and gram-negative bacteria increased with age, whereas the number of birds yielding lactobacilli and yeasts decreased with age. The organisms isolated and their significance as potential pathogens in psittacine birds are discussed.     

Pathogenic bacteria and fungi associated with external ocular diseases in dogs: 131 cases (1981-1986)

Medical records of 131 dogs with external ocular diseases were reviewed. Bacteriologic culture of swab specimens from 151 eyes revealed 100 eyes (66.2%) were considered positive for potentially pathogenic microorganisms. Of 127 species of microorganisms (bacterial and fungal) isolated, 50 (39.3%) were Staphylococcus spp (S intermedius, 17.3%). Streptococcus spp were the next most frequently isolated organism at 32 (25.2%), (Str canis, 16.5%). beta-Hemolytic streptococci (17%) were isolated more frequently than were alpha-hemolytic streptococci (9%), and coagulase-positive staphylococcal species (29%) were isolated almost 3 times as often as were coagulase-negative species (11%). Fungal and yeast organisms were isolated from 4.6% of the eyes. In vitro, most Staphylococcus spp were susceptible to cephalothin, bacitracin, and gentamicin, whereas most Streptococcus spp were susceptible to chloramphenicol, erythromycin, carbenicillin, and cephalothin. Pseudomonas spp were sensitive to tobramycin, gentamicin, and amikacin.     

Conjunctival fungal flora in horses, cattle, dogs, and cats

Conjunctival swab specimens were obtained from both eyes of 43 horses, 25 cows, 50 dogs, and 25 cats without keratitis or other ophthalmologic problems. Fungi were isolated from 95% of the horses, 100% of the cows, 22% of the dogs, and 40% of the cats. Aspergillus spp were isolated from 56% of the horses, 12% of the cows, 8% of the cats, and none of the dogs. Penicillium spp and Cladosporium spp were isolated ubiquitously. Collectively, 28 species from 209 isolants were identified.     

Oral associated bacterial infection in horses: studies on the normal anaerobic flora from the pharyngeal tonsillar surface and its association with lower respiratory tract and paraoral infections

Two hundred and seventy bacterial isolates were obtained from the pharyngeal tonsillar surface of 12 normal horses and 98 obligatory anaerobic bacteria were characterised. Of these, 57 isolates belonging to 7 genera (Peptostreptococcus (1); Eubacterium (9); Clostridium (6); Veillonella (6); Megasphera (1); Bacteroides (28); Fusobacterium (6)) were identified, and 16 of these were identified to species level (P. anaerobius (1); E. fossor (9); C. villosum (1); B. fragilis (1); B. tectum (2); B. heparinolyticus (2)). Three hundred and twenty isolates were obtained from 23 samples from horses with lower respiratory tract (LRT) or paraoral (PO) bacterial infections. Of the 143 bacteria selected for detailed characterisation, obligate anaerobes accounted for 100 isolates, facultative anaerobes for 42 isolates and obligate aerobes for one isolate. Phenotypic characterisation separated 99 of the isolates into 14 genera. Among the obligately anaerobic species, Gram-positive cocci including P. anaerobius comprised 25% of isolates, E. fossor 11% and other Gram-positive rods (excluding Clostridium sp.) 18% of isolates. The Gram-negative rods comprised B. fragilis 5%, B. heparinolyticus 5%, asaccharolytic pigmented Bacteroides 3% and other Bacteroides 13%, while a so-far unnamed species of Fusobacterium (7%), and Gram-negative corroding rods (3%) were isolated. Among the facultatively anaerobic isolates, S. equi subsp. zooepidemicus accounted for 31% of isolates, followed by Pasteurella spp. 19%, Escherichia coli 17%, Actinomyces spp. 9%, Streptococcus spp. 9%. Incidental facultative isolates were Enterococcus spp. 2%, Enterobacter cloaceae 2%, Actinobacillus spp. 2% and Gram-negative corroding rods 5%. On the basis of the similarities (as determined by DNA hybridization data and/or phenotypic characteristics) of some of the bacterial species (e.g. E. fossor and B. heparinolyticus) isolated from both the normal pharyngeal tonsillar surfaces and LRT and PO diseases of horses, it is considered that the most likely source of bacteria involved in these disease processes is flora from the oral cavity.     

Aerobic and anaerobic bacterial isolates from horses with pneumonia or pleuropneumonia and antimicrobial susceptibility patterns of the aerobes

Frequency of aerobic and anaerobic isolates in 327 aspirates and in 123 pleural fluid samples from 327 horses with pneumonia or pleuropneumonia and antimicrobial susceptibility patterns of the aerobes were reported. Of the 327 horses, 75% survived, 20% were euthanatized, and 5% died. Tracheobronchial aspirates or pleural fluid specimens from 25 of the horses did not yield growth. Of the remaining 302 horses, 221 had only aerobic organisms isolated, whereas only anaerobes were isolated from 6 of the 302 horses. The remaining 75 horses had mixed aerobic and anaerobic bacterial infections. The survival rates for horses with aerobic only isolates was twice that of horses with anaerobic isolates. The aerobic bacteria most frequently isolated were beta-Streptococcus spp, Pasteurella spp, Escherichia coli, and Enterobacter spp. The anaerobic species most frequently isolated were Bacteroides spp and Clostridium spp.     

In vitro fungistatic and fungicidal activities of silver sulfadiazine and natamycin on pathogenic fungi isolated from horses with keratomycosis

OBJECTIVE: To evaluate the in vitro antifungal properties of silver sulfadiazine (SSD) and natamycin against filamentous fungi isolated from eyes of horses with keratomycosis. SAMPLE POPULATION: Filamentous fungal isolates obtained from eyes of keratomycosis-affected horses. PROCEDURES: Fungal culture of ocular samples yielded 6 Fusarium spp; 7 Aspergillus spp; and 1 isolate each of Curvularia, Scopulariopsis, Penicillium, and Chrysosporium. For each fungal isolate, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of SSD and natamycin were determined. RESULTS: For all 17 fungal isolates, SSD MIC distribution ranged from < or = 1 to > 64 microg/mL; MIC50 and MIC90 (MICs at which 50% and 90% of organisms were inhibited) were 4 and 32 microg/mL, respectively. The SSD MFC distribution for all isolates was < or = 1 to > 64 microg/mL; MFC50 and MFC90 (MFCs at which 50% and 90% of organisms were killed) were 8 and > 64 microg/mL, respectively. For all fungal isolates, natamycin MIC distribution ranged from 256 to > 1,000 microg/mL; MIC50 and MIC90 were 512 and > 1,000 microg/mL, respectively. The natamycin MFC distribution for all isolates ranged from 512 to > 1,000 microg/mL; MFC(50) and MFC(90) were each > 1,000 microg/mL. CONCLUSIONS AND CLINICAL RELEVANCE: These in vitro data suggest that SSD is fungicidal against the fungal isolates that were obtained from eyes of horses with keratomycosis and that natamycin is fungicidal against some of the isolates at the drug concentrations evaluated. Silver sulfadiazine may be a therapeutic option for equine keratomycosis.     

Increase of bacterial resistance in human medicine by resistance genes of bacteria from meat supplying animals

Two different groups of bacteria carrying genes encoding for resistance to antibiotics may be transmitted from animals to humans via food products: a.) obligate infectious agents (enteric pathogens, e.g. Salmonella enterica spp., Campylobacter spp., EHEC) and b) facultative pathogenic species (e.g. E. coli, enterococci). Thus far, it is unknown whether genes encoding for resistance to antibiotics from these bacteria may be transferred to bacteria in normal flora of the host. The transfers of genes encoding for resistance to vancomycin from animal sources to the mucosa of humans has been suggested. Thus, there is a threat that these plasmid-encoded resistance genes may also be transferred to other gram-positive organisms present in the human flora. Vancomycin is the antibiotic in reserve for treatment of infections caused by oxacillin (methicillin) resistant strains of S. aureus and by strains of pneumococcus resistant to penicillin.     

Cloacal flora isolated from wild black-bellied whistling ducks (Dendrocygna autumnalis) in Laguna La Nacha, Mexico.

Cloacal swabs from 110 adult black-bellied whistling ducks trapped at Laguna La Nacha, Tamaulipas, Mexico, were cultured to determine the prevalence of normal and potentially pathogenic bacteria. Twenty-five gram-negative enterobacteria and four gram-positive cocci were isolated. The most common isolates included Escherichia coli (54%), Staphylococcus spp. (29%), Streptococcus spp. (22%), Aeromonas hydrophila (15%) Enterobacter cloacae (14%), and Micrococcus sp. (14%). The implications of whistling ducks as possible reservoirs of pathogenic bacteria are discussed.     

Bacterial and fungal pathogens isolated from corneal ulcerations in domesticated elephants (Elephas maximus maximus) in Sri Lanka

Infective corneal diseases are common among the domesticated elephants in Sri Lanka, causing morbidity including blindness leading to loss of revenue to their owners. From 140 elephants of different ages and both sexes, 36 animals (25.7%) had evidence of keratitis, corneal ulcers, corneal opacities, and some had foreign bodies in their eyes. Nine elephants (6.4%) had lesions in both eyes (6.41%). Cultures for both bacteria and fungi were obtained from 26 corneal ulcers, including the nine elephants with bilateral lesions. The other 10 animals could not be restrained for sample collection. Swabs from the normal corneas of an additional 20 elephants without signs of any ophthalmic diseases were also collected. Twenty-three of the 35 (65.71%) samples from affected corneas yielded bacterial pathogens, and 14 (40%) also had fungal isolates. None of them yielded a fungal isolate alone. The predominant bacteria isolated were Staphylococcus aureus , beta hemolytic streptococci and coliforms. Fusarium , Cladosporium , Curvularia and Aspergillus species were the primary fungal isolates. No bacteria or filamentous fungi were isolated from the eyes with the normal corneas. Microbial identification including fungal isolations is suggested in the management of infective corneal diseases in elephants.     

Comparison of Two Methods for Presurgical Disinfection of the Equine Hoof

OBJECTIVES: To determine for equine hooves the normal resident aerobic bacterial population and the efficacy of 2 methods of disinfection. Study Design-Measurement of total bacterial, gram-positive bacterial, and gram-negative bacterial surface populations from the frog, sole, and hoof wall after each step of 2 different preoperative surgical disinfection techniques. ANIMALS: Six adult horses. METHODS: Hoof wall, sole, and frog samples were collected for quantitative bacteriology before, during, and after 2 multistep antiseptic preparation techniques: Method A-6-minute scrub with povidone-iodine soap, followed by 24-hour submersion in povidone-iodine solution-soaked cotton; and Method B-initial removal of superficial layer of hoof capsule before completing Method A disinfection procedures. RESULTS: Removal of the superficial hoof layer, application of the povidone iodine scrub, and completion of the povidone-iodine soak all significantly (P < .0008) decreased total bacterial numbers. Method B had significantly lower bacterial counts than method A at each consecutive step. Final total bacterial counts remained greater than 10(5) bacteria per gram of tissue regardless of preparation method. CONCLUSIONS: The hoof surface hosts a broad spectrum of aerobic gram-positive and -negative bacteria, many of which are potential pathogens. Bacterial numbers can be significantly reduced by removal of the superficial hoof surface, by application of a povidone-iodine scrub, and by use of a 24-hour povidone-iodine soak. However, bacterial populations >10(5) g per tissue persist after these disinfection procedures. CLINICAL RELEVANCE: Regardless of the preparation methods used in this study, bacterial populations capable of inducing wound infection remain on the hoof capsule.     

In vitro susceptibility patterns of fungi associated with keratomycosis in horses of the northeastern United States: 68 cases (1987-2006)

OBJECTIVE: To determine in vitro susceptibility patterns of fungi associated with keratomycosis in horses in the northeastern United States and compare those patterns with results of studies from other geographic regions. DESIGN: Retrospective case series. ANIMALS: 68 horses with keratomycosis. PROCEDURES: Medical records of horses with a clinical diagnosis of keratomycosis, positive results of corneal fungal cultures, and susceptibility data were reviewed from the years 1987 to 2006. Fungal identification and in vitro antifungal susceptibility test results were recorded. The percentage of susceptible isolates was compared among antifungals for all isolates together and for the most common genera individually. RESULTS: 74 fungal isolates from 68 horses that met inclusion criteria were identified. Aspergillus, Candida, and Fusarium spp were the most frequent isolates. Grouped isolates had the highest percentage of susceptibility to nystatin (87.7%), natamycin (87.5%), and clotrimazole (80.6%). Grouped isolates had the lowest percentage of susceptibility to fluconazole (15.8%) and miconazole (27.5%). Aspergillus spp (> or = 81.0%) were most susceptible to nystatin, clotrimazole, itraconazole, and natamycin. Candida spp (100%) were most susceptible to ketaconazole, natamycin, and nystatin. Fusarium spp (100%) were only consistently susceptible to natamycin. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of in vitro susceptibility testing, nystatin, natamycin, or clotrimazole is recommended for initial topical treatment of keratomycosis in horses from the northeastern United States. Contrary to results of studies of ocular fungal isolates of horses from other regions, Candida spp were identified more frequently and miconazole had lower in vitro efficacy in the present study.     

Bacterial infection of the lower respiratory tract in 34 horses

OBJECTIVE: To investigate associations between the bacteriology and aspects of history, clinical presentation, outcome and pathology of lower respiratory tract disease of 34 horses. PROCEDURE: Detailed aerobic and anaerobic bacteriological investigations were performed on clinical specimens from horses with pneumonia, lung abscessation and necrotic pneumonia with or without pleurisy in an attempt to identify those bacteria that might contribute to the initiation and progression of infection. RESULTS: Bacteria were cultured from 33 of the 34 horses. In ten cases, only aerobic/facultatively anaerobic isolates were cultured while aerobic/facultatively anaerobic bacteria and obligately anaerobic bacteria were isolated in the other 23 cases. Moderate to large numbers of anaerobic bacteria were isolated only when the estimated duration of illness was at least five days. Bacteria were not cultured from 12 of the pleural fluid samples but were always cultured from pulmonary samples (either transtracheal aspirates from live horses or pulmonary lesions at necropsy). Streptococcus equi subsp zooepidemicus was isolated in the three cases where only one bacterial species was cultured. In the other 30 cases, multiple species were isolated. These included most often and in greatest numbers, Streptococcus equi subsp zooepidemicus, Pasteurellaceae, Escherichia coli, anaerobic cocci, Eubacterium fossor, Bacteroides tectum, Prevotella heparinolytica, Fusobacterium spp, and pigmented members of the genera Prevotella and Porphyromonas. Aerobic/facultatively anaerobic organisms were isolated from 97% of horses, while obligately anaerobic organisms were cultured from 68% of horses. CONCLUSION: There was no association between the isolation of any specific bacterium and the outcome of disease. However, obligately anaerobic bacteria (such as anaerobic cocci, Bacteroides tectum, P heparinolytica and Fusobacterium spp) and the facultatively anaerobic species Escherichia coli, were recovered more commonly from horses that died or were euthanased than from those that survived. There was an association between failure of horses to recover from pleuropneumonia and delay in diagnosis and initiation of treatment.     

Normal ocular features, conjunctival microflora and intraocular pressure in the Canadian beaver (Castor canadensis)

Objective The aim of the study was to assess the ocular features, normal conjunctival bacterial and fungal flora, and intraocular pressure (IOP) in the Canadian beaver (Castor canadensis). Sample population Sixteen, apparently healthy beavers with no evidence of ocular disease, and live‐trapped in regions throughout Prince Edward Island. Procedures The beavers were sedated with intramuscular ketamine (12–15 mg/kg). Two culture specimens were obtained from the ventral conjunctival sac of both eyes of 10/16 beavers for aerobic and anaerobic bacterial and fungal identifications. The anterior ocular structures of all beavers were evaluated using a transilluminator and slit lamp biomicroscope. Palpebral fissure length (11/16 beavers), and horizontal and vertical corneal diameters (10/16 beavers) were measured. IOPs were measured in both eyes of 11/16 beavers using applanation tonometry. Both eyes of 3/16 beavers and one eye of 1/16 beavers were dilated using topical tropicamide prior to sedation to effect timely maximal dilation. Culture specimens and IOPs were not evaluated in these four animals. Indirect ophthalmoscopy was performed on 7/8 eyes of these four beavers. Results Conjunctival specimens from all eyes cultured positively for one or more isolates of aerobic bacteria. The most common isolate was Micrococcus spp. (five beavers; 9/20 eyes). Other isolates included a Gram‐positive coccobacilli‐like organism (four beavers; 7/20 eyes), Aeromonas hydrophila (three beavers; 4/20 eyes), Staphylococcus spp. (three beavers; 4/20 eyes), Gram positive bacilli (one beaver; 2/20 eyes), Enterobacter spp. (two beavers; 2/20 eyes), Streptococcus spp. (two beavers; 2/20 eyes), aerobic diphtheroids (one beaver; 1/20 eyes), and Pseudomonas spp. (one beaver; 1/20 eyes). Clostridium sordellii (one beaver; 1/20 eyes) and Peptostreptococcus spp. (one beaver; 1/20 eyes) were the sole anaerobic bacteria isolated. All conjunctival specimens were negative for growth of fungi. Ophthalmic examinations revealed the normal beaver eye and ocular adnexa included dorsal and ventral puncta, a vestigial third eyelid, and a circular pupil. Average palpebral fissure length was 9.36 mm (SD = 1.00) for both eyes. Mean horizontal and vertical corneal diameters of both eyes were 9.05 mm (SD = 0.64) and 8.45 mm (SD = 0.69), respectively. Mean IOP for the right and left eyes were 17.11 mmHg (SD = 6.39) and 18.79 mmHg (SD = 5.63), respectively. Indirect ophthalmoscopic examinations revealed normal anangiotic retinas. Conclusions Gram‐positive aerobes were most commonly cultured from the conjunctival sac of normal beavers, with Micrococcus spp. predominating. The overall mean IOP in ketamine‐sedated beavers was 17.95 mmHg. The beaver, an amphibious rodent, has an anangiotic retina.