Identification of bacteria and fungi sampled from the conjunctival surface of normal horses in South‐East Queensland, Australia

Hampson, E. C. G. M.; Gibson, Justine S.; Barot, M S; Shapter, Frances M; Greer, Ristan M.

doi:10.1111/vop.12587

Cited by 21 publications

(40 citation statements)

References 17 publications

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“…The most frequently isolated bacteria were gram-positive (Table 1), which is consistent with other studies 14,[23][24][25] but in contrast to Johns et al who found the gram-negative rod Acinetobacter to predominate in conjunctival samples from healthy horse eyes in the South East of the UK. 20 It is also in contrast to a study from Florida, USA, where Pseudomonas aeruginosa and Streptococcus spp.…”

Section: Discussionsupporting

confidence: 90%

Changes in antimicrobial resistance patterns of ocular surface bacteria isolated from horses in the UK: An eight‐year surveillance study (2012‐2019)

Chalder

Knott²,

Rushton³

et al. 2020

Veterinary Ophthalmology

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Purpose To identify temporal changes in antimicrobial resistance of ocular surface bacteria isolated from clinically symptomatic equine eyes in the South West of the UK. Study design Retrospective. Methods Clinical and laboratory records of horses treated for suspected bacterial ocular surface disease (ulcerative and non‐ulcerative) at a single facility between January 2011 and December 2019 were reviewed. Cases were included if they underwent ocular surface sampling, aerobic bacterial culture, and antimicrobial susceptibility testing. Cases were split into two time periods based on when sampling occurred: “early” (2012‐2015) and “late” (2016‐2019) to enable identification of temporal trends in resistance to chloramphenicol, gentamicin, fusidic acid, neomycin, cloxacillin, ofloxacin, and polymyxin B. Results A total of 125 samples from 110 horses were included in analyses. Culture‐positive isolates were identified in 76/110 (60.8%) samples. Principal isolates included Staphylococci spp. (n = 45; 64.3%), Streptococci spp. (n = 14; 20%), and Enterobacter spp. (n = 11; 15.7%). There was a significant increase in resistance to chloramphenicol over time (P = .007) and a decrease in resistance to ofloxacin that approached significance (P = .059). Chloramphenicol (100%) and gentamicin (85.7%) had the highest overall in‐vitro efficacy during the early and late periods, respectively. There was no significant difference in the type of bacteria isolated across the two time periods. Conclusions These results suggest a potential increase in resistance to chloramphenicol among bacteria isolated from the ocular surface of horses in the South West UK, reinforcing the value of surveillance to guide the empirical use of antimicrobials.

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Section: Discussionsupporting

confidence: 90%

Changes in antimicrobial resistance patterns of ocular surface bacteria isolated from horses in the UK: An eight‐year surveillance study (2012‐2019)

Chalder

Knott²,

Rushton³

et al. 2020

Veterinary Ophthalmology

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“…Overall, the ocular surface is not abundantly colonized by bacteria, with frequent reports of no growth from samples of healthy horse eyes [2, 9–12]. This finding highlights the limitations of culture-based methods, as many bacterial organisms do not grow well in laboratory conditions and thus cannot be readily identified in a given sample.…”

Section: Introductionmentioning

confidence: 99%

“…Traditionally, bacterial microorganisms on the ocular surface of both healthy and diseased horses have been studied using conventional culture-based techniques [1–4,8–12]. Gram-positive bacteria were reported to predominate the equine ocular surface, with Bacillus , Staphylococcus , Streptococcus , and Corynebacterium spp .…”

Section: Introductionmentioning

confidence: 99%

“…Gram-positive bacteria were reported to predominate the equine ocular surface, with Bacillus , Staphylococcus , Streptococcus , and Corynebacterium spp . commonly cultured regardless of geography, climate, or season [1–4,8–12]. Less frequent isolates included gram-negative bacterial microbes such as Moraxella , Acinetobacter , Neisseria and Pseudomonas spp .…”

Section: Introductionmentioning

confidence: 99%

“…Less frequent isolates included gram-negative bacterial microbes such as Moraxella , Acinetobacter , Neisseria and Pseudomonas spp . [1–4,8–12]. Very few culture-based studies have evaluated changes in the ocular surface microbiota over time or following topical antibiotic use [4,10].…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of the bacterial ocular surface microbiome in clinically normal horses before and after treatment with topical neomycin-polymyxin-bacitracin

et al. 2019

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Next generation sequencing (NGS) studies have demonstrated a rich and diverse ocular surface-associated microbiota in people that was previously undetected by traditional culture-based methods. The ocular surface microbiome of horses has yet to be investigated using NGS techniques. This study aimed to determine the bacterial composition of the ocular surface microbiome in healthy horses, and to identify whether there are microbial community changes over time and following topical antibiotic use. One eye of 12 horses was treated 3 times daily for 1 week with neomycin-polymyxin-bacitracin ophthalmic ointment. Contralateral eyes served as untreated controls. The inferior conjunctival fornix of both eyes was sampled at baseline prior to initiating treatment (day 0), after 1 week of treatment (day 7), and 4 weeks after concluding treatment (day 35). Genomic DNA was extracted from ocular surface swabs and sequenced using primers that target the V4 region of bacterial 16S rRNA. At baseline, the most abundant phyla identified were Proteobacteria (46.1%), Firmicutes (24.6%), Actinobacteria (12.6%), and Bacteroidetes (11.2%). The most abundant families included Pasteurellaceae (13.7%), Sphingomonadaceae (7.9%), an unclassified Order of Cardiobacteriales (7.7%), and Moraxellaceae (4.8%). Alpha and beta diversity measurements were unchanged in both treatment and control eyes over time. Overall, the major bacterial taxa on the equine ocular surface remained stable over time and following topical antibiotic therapy.

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Cytology of the Eyes and Associated Structures

Piccione

Vallone

2020

Equine Hematology, Cytology, and Clinical Chemistry

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Identification of bacteria and fungi sampled from the conjunctival surface of normal horses in South‐East Queensland, Australia

Abstract: Bacteria and fungi were commonly isolated from the eyes of healthy horses. The antibiotic and antifungal susceptibilities identified can be used as a guide for empirical therapy after cytology in the treatment of corneal ulceration in horses.

Cited by 21 publications

References 17 publications

Changes in antimicrobial resistance patterns of ocular surface bacteria isolated from horses in the UK: An eight‐year surveillance study (2012‐2019)

Changes in antimicrobial resistance patterns of ocular surface bacteria isolated from horses in the UK: An eight‐year surveillance study (2012‐2019)

Evaluation of the bacterial ocular surface microbiome in clinically normal horses before and after treatment with topical neomycin-polymyxin-bacitracin

Cytology of the Eyes and Associated Structures

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