Tags

Type your tag names separated by a space and hit enter

In vitro antimicrobial activity of narasin against common clinical isolates associated with canine otitis externa.
Vet Dermatol. 2018 Apr; 29(2):149-e57.VD

Abstract

BACKGROUND

Antimicrobial resistance and antimicrobial stewardship are of ever-increasing importance in veterinary medicine. Re-purposing of old drugs that are not used in human medicine is one approach that addresses the emergence of multidrug resistance in canine skin and ear infections, and can reduce the use of critically important human antibiotic classes.

HYPOTHESIS/OBJECTIVES

To determine the antimicrobial activity of narasin, a polyether ionophore conventionally used as a rumen modifier and anticoccidial agent in production animals, against common clinical isolates of canine otitis externa (OE).

ANIMALS/ISOLATES

Clinical isolates (n = 110) from canine OE were tested, including 17 meticillin-susceptible Staphylococcus pseudintermedius (MSSP), 13 multidrug-resistant Staphylococcus pseudintermedius (MDRSP), and 20 each of β-haemolytic Streptococcus spp., Pseudomonas aeruginosa, Proteus mirabilis and Malassezia pachydermatis.

METHODS

Bacterial and yeast isolates were subcultured, suspended in broth and inoculated into 96-well plates. Organisms were tested against concentrations of narasin ranging from 0.03 to 128 μg/mL. Minimal inhibitory concentrations (MICs) were determined after overnight incubation.

RESULTS

Narasin MICs for staphylococcal and streptococcal isolates ranged from 0.06 to 0.25 μg/mL; MIC50 and MIC90 values for both organisms were 0.125 μg/mL. No MICs were achieved for Pseudomonas or Proteus isolates. There was a weak antifungal effect against M. pachydermatis isolates (MIC 32 to >128 μg/mL).

CONCLUSIONS AND CLINICAL RELEVANCE

Narasin was effective against Gram-positive bacteria and had antifungal activity at higher concentrations against M. pachydermatis. However, the lack of Gram-negative activity would prevent its use as a sole antimicrobial agent in cases of canine OE.

Authors+Show Affiliations

Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, 5371, Australia.Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, 5371, Australia.Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, 5371, Australia.Luoda Pharma Pty. Ltd., 1/304-318 Kingsway, Caringbah, NSW, 2229, Australia.Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, 5371, Australia.Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, 5371, Australia.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

29363210

Citation

Chan, Wei Yee, et al. "In Vitro Antimicrobial Activity of Narasin Against Common Clinical Isolates Associated With Canine Otitis Externa." Veterinary Dermatology, vol. 29, no. 2, 2018, pp. 149-e57.
Chan WY, Hickey EE, Khazandi M, et al. In vitro antimicrobial activity of narasin against common clinical isolates associated with canine otitis externa. Vet Dermatol. 2018;29(2):149-e57.
Chan, W. Y., Hickey, E. E., Khazandi, M., Page, S. W., Trott, D. J., & Hill, P. B. (2018). In vitro antimicrobial activity of narasin against common clinical isolates associated with canine otitis externa. Veterinary Dermatology, 29(2), 149-e57. https://doi.org/10.1111/vde.12516
Chan WY, et al. In Vitro Antimicrobial Activity of Narasin Against Common Clinical Isolates Associated With Canine Otitis Externa. Vet Dermatol. 2018;29(2):149-e57. PubMed PMID: 29363210.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - In vitro antimicrobial activity of narasin against common clinical isolates associated with canine otitis externa. AU - Chan,Wei Yee, AU - Hickey,Elizabeth E, AU - Khazandi,Manouchehr, AU - Page,Stephen W, AU - Trott,Darren J, AU - Hill,Peter B, Y1 - 2018/01/24/ PY - 2017/11/19/accepted PY - 2018/1/25/pubmed PY - 2019/1/31/medline PY - 2018/1/25/entrez SP - 149 EP - e57 JF - Veterinary dermatology JO - Vet. Dermatol. VL - 29 IS - 2 N2 - BACKGROUND: Antimicrobial resistance and antimicrobial stewardship are of ever-increasing importance in veterinary medicine. Re-purposing of old drugs that are not used in human medicine is one approach that addresses the emergence of multidrug resistance in canine skin and ear infections, and can reduce the use of critically important human antibiotic classes. HYPOTHESIS/OBJECTIVES: To determine the antimicrobial activity of narasin, a polyether ionophore conventionally used as a rumen modifier and anticoccidial agent in production animals, against common clinical isolates of canine otitis externa (OE). ANIMALS/ISOLATES: Clinical isolates (n = 110) from canine OE were tested, including 17 meticillin-susceptible Staphylococcus pseudintermedius (MSSP), 13 multidrug-resistant Staphylococcus pseudintermedius (MDRSP), and 20 each of β-haemolytic Streptococcus spp., Pseudomonas aeruginosa, Proteus mirabilis and Malassezia pachydermatis. METHODS: Bacterial and yeast isolates were subcultured, suspended in broth and inoculated into 96-well plates. Organisms were tested against concentrations of narasin ranging from 0.03 to 128 μg/mL. Minimal inhibitory concentrations (MICs) were determined after overnight incubation. RESULTS: Narasin MICs for staphylococcal and streptococcal isolates ranged from 0.06 to 0.25 μg/mL; MIC50 and MIC90 values for both organisms were 0.125 μg/mL. No MICs were achieved for Pseudomonas or Proteus isolates. There was a weak antifungal effect against M. pachydermatis isolates (MIC 32 to >128 μg/mL). CONCLUSIONS AND CLINICAL RELEVANCE: Narasin was effective against Gram-positive bacteria and had antifungal activity at higher concentrations against M. pachydermatis. However, the lack of Gram-negative activity would prevent its use as a sole antimicrobial agent in cases of canine OE. SN - 1365-3164 UR - https://www.unboundmedicine.com/medline/citation/29363210/In_vitro_antimicrobial_activity_of_narasin_against_common_clinical_isolates_associated_with_canine_otitis_externa_ L2 - https://doi.org/10.1111/vde.12516 DB - PRIME DP - Unbound Medicine ER -