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Biofilm production by pathogens associated with canine otitis externa, and the antibiofilm activity of ionophores and antimicrobial adjuvants.
J Vet Pharmacol Ther. 2019 Nov; 42(6):682-692.JV

Abstract

Otitis externa (OE) is a frequently reported disorder in dogs associated with secondary infections by Staphylococcus, Pseudomonas and yeast pathogens. The presence of biofilms may play an important role in the resistance of otic pathogens to antimicrobial agents. Biofilm production of twenty Staphylococcus pseudintermedius and twenty Pseudomonas aeruginosa canine otic isolates was determined quantitatively using a microtiter plate assay, and each isolate was classified as a strong, moderate, weak or nonbiofilm producer. Minimum biofilm eradication concentration (MBEC) of two ionophores (narasin and monensin) and three adjuvants (N-acetylcysteine (NAC), Tris-EDTA and disodium EDTA) were investigated spectrophotometrically (OD570nm) and quantitatively (CFU/ml) against selected Staphylococcus and Pseudomonas biofilm cultures. Concurrently, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of planktonic cultures were assessed. 16/20 of the S. pseudintermedius clinical isolates were weak biofilm producers. 19/20 P. aeruginosa clinical isolates produced biofilms and were distributed almost equally as weak, moderate and strong biofilm producers. While significant antibiofilm activity was observed, no MBEC was achieved with narasin or monensin. The MBEC for NAC ranged from 5,000-10,000 µg/ml and from 20,000-80,000 µg/ml against S. pseudintermedius and P. aeruginosa, respectively. Tris-EDTA eradicated P. aeruginosa biofilms at concentrations ranging from 6,000/1,900 to 12,000/3,800 µg/ml. The MBEC was up to 16-fold and eightfold higher than the MIC/MBC of NAC and Tris-EDTA, respectively. Disodium EDTA reduced biofilm growth of both strains at concentrations of 470 µg/ml and higher. It can be concluded that biofilm production is common in pathogens associated with canine OE. NAC and Tris-EDTA are effective antibiofilm agents in vitro that could be considered for the treatment of biofilm-associated OE in dogs.

Authors+Show Affiliations

Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia. Faculty of Veterinary Medicine, Universiti Putra Malaysia, Selangor, Malaysia.Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia.Luoda Pharma Pty. Ltd, Caringbah, NSW, Australia.Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia.Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31503362

Citation

Chan, Wei Yee, et al. "Biofilm Production By Pathogens Associated With Canine Otitis Externa, and the Antibiofilm Activity of Ionophores and Antimicrobial Adjuvants." Journal of Veterinary Pharmacology and Therapeutics, vol. 42, no. 6, 2019, pp. 682-692.
Chan WY, Hickey EE, Page SW, et al. Biofilm production by pathogens associated with canine otitis externa, and the antibiofilm activity of ionophores and antimicrobial adjuvants. J Vet Pharmacol Ther. 2019;42(6):682-692.
Chan, W. Y., Hickey, E. E., Page, S. W., Trott, D. J., & Hill, P. B. (2019). Biofilm production by pathogens associated with canine otitis externa, and the antibiofilm activity of ionophores and antimicrobial adjuvants. Journal of Veterinary Pharmacology and Therapeutics, 42(6), 682-692. https://doi.org/10.1111/jvp.12811
Chan WY, et al. Biofilm Production By Pathogens Associated With Canine Otitis Externa, and the Antibiofilm Activity of Ionophores and Antimicrobial Adjuvants. J Vet Pharmacol Ther. 2019;42(6):682-692. PubMed PMID: 31503362.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Biofilm production by pathogens associated with canine otitis externa, and the antibiofilm activity of ionophores and antimicrobial adjuvants. AU - Chan,Wei Yee, AU - Hickey,Elizabeth E, AU - Page,Stephen W, AU - Trott,Darren J, AU - Hill,Peter B, Y1 - 2019/09/10/ PY - 2019/06/21/received PY - 2019/08/13/revised PY - 2019/08/21/accepted PY - 2019/9/11/pubmed PY - 2020/4/29/medline PY - 2019/9/11/entrez KW - Pseudomonas aeruginosa KW - Staphylococcus pseudintermedius KW - N-acetylcysteine KW - Tris-EDTA KW - biofilms KW - canine otitis externa KW - ionophores SP - 682 EP - 692 JF - Journal of veterinary pharmacology and therapeutics JO - J. Vet. Pharmacol. Ther. VL - 42 IS - 6 N2 - Otitis externa (OE) is a frequently reported disorder in dogs associated with secondary infections by Staphylococcus, Pseudomonas and yeast pathogens. The presence of biofilms may play an important role in the resistance of otic pathogens to antimicrobial agents. Biofilm production of twenty Staphylococcus pseudintermedius and twenty Pseudomonas aeruginosa canine otic isolates was determined quantitatively using a microtiter plate assay, and each isolate was classified as a strong, moderate, weak or nonbiofilm producer. Minimum biofilm eradication concentration (MBEC) of two ionophores (narasin and monensin) and three adjuvants (N-acetylcysteine (NAC), Tris-EDTA and disodium EDTA) were investigated spectrophotometrically (OD570nm) and quantitatively (CFU/ml) against selected Staphylococcus and Pseudomonas biofilm cultures. Concurrently, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of planktonic cultures were assessed. 16/20 of the S. pseudintermedius clinical isolates were weak biofilm producers. 19/20 P. aeruginosa clinical isolates produced biofilms and were distributed almost equally as weak, moderate and strong biofilm producers. While significant antibiofilm activity was observed, no MBEC was achieved with narasin or monensin. The MBEC for NAC ranged from 5,000-10,000 µg/ml and from 20,000-80,000 µg/ml against S. pseudintermedius and P. aeruginosa, respectively. Tris-EDTA eradicated P. aeruginosa biofilms at concentrations ranging from 6,000/1,900 to 12,000/3,800 µg/ml. The MBEC was up to 16-fold and eightfold higher than the MIC/MBC of NAC and Tris-EDTA, respectively. Disodium EDTA reduced biofilm growth of both strains at concentrations of 470 µg/ml and higher. It can be concluded that biofilm production is common in pathogens associated with canine OE. NAC and Tris-EDTA are effective antibiofilm agents in vitro that could be considered for the treatment of biofilm-associated OE in dogs. SN - 1365-2885 UR - https://www.unboundmedicine.com/medline/citation/31503362/Biofilm_production_by_pathogens_associated_with_canine_otitis_externa_and_the_antibiofilm_activity_of_ionophores_and_antimicrobial_adjuvants_ L2 - https://doi.org/10.1111/jvp.12811 DB - PRIME DP - Unbound Medicine ER -