Levamisole as a Strategy Against Bacteria from Canine Otitis Externa: An In Vitro Evaluation
Canine otitis externa is a prevalent condition, and inadequate treatment may favor the emergence of multidrug-resistant microorganisms. Drug repurposing provides an alternative approach for the management of this disease. Thus, this study aimed at assessing the antimicrobial and antibiofilm properti...
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MDPI AG
2025-07-01
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| Series: | Veterinary Sciences |
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| Online Access: | https://www.mdpi.com/2306-7381/12/7/640 |
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| author | Rodrigo F. M. Guedes Ana C. C. F. Soares Francisco I. F. Gomes Alyne S. Freitas Vinicius C. Pereira Rossana A. Cordeiro Marcos F. G. Rocha José J. C. Sidrim Giovanna R. Barbosa Glaucia M. M. Guedes Debora S. C. M. Castelo-Branco |
| author_facet | Rodrigo F. M. Guedes Ana C. C. F. Soares Francisco I. F. Gomes Alyne S. Freitas Vinicius C. Pereira Rossana A. Cordeiro Marcos F. G. Rocha José J. C. Sidrim Giovanna R. Barbosa Glaucia M. M. Guedes Debora S. C. M. Castelo-Branco |
| author_sort | Rodrigo F. M. Guedes |
| collection | DOAJ |
| description | Canine otitis externa is a prevalent condition, and inadequate treatment may favor the emergence of multidrug-resistant microorganisms. Drug repurposing provides an alternative approach for the management of this disease. Thus, this study aimed at assessing the antimicrobial and antibiofilm properties of levamisole against bacterial strains recovered from dogs with otitis externa as well as its influence on biofilm growth dynamics during 120 h. A total of 50 clinical bacterial isolates were subjected to analysis. Planktonic bacterial susceptibility to levamisole was assessed by broth microdilution to determine the minimum inhibitory concentration (MIC), the lowest concentration that completely inhibits bacterial growth. The activity against mature biofilms was assessed by determining the minimum biofilm eradication concentration (MBEC). The effect of levamisole on biofilm formation was evaluated at the MIC and at two subinhibitory concentrations, with daily readings recorded at 48, 72, 96, and 120 h. MICs of levamisole ranged from 0.58 to 2.34 mg/mL. Levamisole reduced the biomass of mature biofilms (<i>p</i> < 0.05), with MBEC values ranging from 1.17 to 18.75 mg/mL, and biofilm formation was significantly reduced at the MIC concentration (1.17 mg/mL) for all isolates for 120 h (<i>p</i> < 0.05). Levamisole demonstrated potential as a preventive approach against biofilm-associated bacterial otitis. |
| format | Article |
| id | doaj-art-b0166886c3c04f7ca4b7b0aaa21c384f |
| institution | DOAJ |
| issn | 2306-7381 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Veterinary Sciences |
| spelling | doaj-art-b0166886c3c04f7ca4b7b0aaa21c384f2025-08-20T02:47:13ZengMDPI AGVeterinary Sciences2306-73812025-07-0112764010.3390/vetsci12070640Levamisole as a Strategy Against Bacteria from Canine Otitis Externa: An In Vitro EvaluationRodrigo F. M. Guedes0Ana C. C. F. Soares1Francisco I. F. Gomes2Alyne S. Freitas3Vinicius C. Pereira4Rossana A. Cordeiro5Marcos F. G. Rocha6José J. C. Sidrim7Giovanna R. Barbosa8Glaucia M. M. Guedes9Debora S. C. M. Castelo-Branco10Course of Veterinary Medicine, Education, Sciencies and Technology Center of the Inhamuns Region, State University of Ceará, Tauá 63660-000, CE, BrazilCourse of Veterinary Medicine, University of Fortaleza, Fortaleza 60811-905, CE, BrazilGroup of Applied Medical Microbiology, Post-Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza 60420-270, CE, BrazilGroup of Applied Medical Microbiology, Post-Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza 60420-270, CE, BrazilGroup of Applied Medical Microbiology, Post-Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza 60420-270, CE, BrazilLaboratory of Infectious Bioagents, Post-Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza 60420-270, CE, BrazilPost-Graduate Program in Veterinary Sciences, College of Veterinary, State University of Ceará, Fortaleza 60714-903, CE, BrazilSpecialized Medical Mycology Center, Post-Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza 60420-270, CE, BrazilGroup of Applied Medical Microbiology, Post-Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza 60420-270, CE, BrazilGroup of Applied Medical Microbiology, Post-Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza 60420-270, CE, BrazilGroup of Applied Medical Microbiology, Post-Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza 60420-270, CE, BrazilCanine otitis externa is a prevalent condition, and inadequate treatment may favor the emergence of multidrug-resistant microorganisms. Drug repurposing provides an alternative approach for the management of this disease. Thus, this study aimed at assessing the antimicrobial and antibiofilm properties of levamisole against bacterial strains recovered from dogs with otitis externa as well as its influence on biofilm growth dynamics during 120 h. A total of 50 clinical bacterial isolates were subjected to analysis. Planktonic bacterial susceptibility to levamisole was assessed by broth microdilution to determine the minimum inhibitory concentration (MIC), the lowest concentration that completely inhibits bacterial growth. The activity against mature biofilms was assessed by determining the minimum biofilm eradication concentration (MBEC). The effect of levamisole on biofilm formation was evaluated at the MIC and at two subinhibitory concentrations, with daily readings recorded at 48, 72, 96, and 120 h. MICs of levamisole ranged from 0.58 to 2.34 mg/mL. Levamisole reduced the biomass of mature biofilms (<i>p</i> < 0.05), with MBEC values ranging from 1.17 to 18.75 mg/mL, and biofilm formation was significantly reduced at the MIC concentration (1.17 mg/mL) for all isolates for 120 h (<i>p</i> < 0.05). Levamisole demonstrated potential as a preventive approach against biofilm-associated bacterial otitis.https://www.mdpi.com/2306-7381/12/7/640canine external otitisbacteriabiofilmslevamisole |
| spellingShingle | Rodrigo F. M. Guedes Ana C. C. F. Soares Francisco I. F. Gomes Alyne S. Freitas Vinicius C. Pereira Rossana A. Cordeiro Marcos F. G. Rocha José J. C. Sidrim Giovanna R. Barbosa Glaucia M. M. Guedes Debora S. C. M. Castelo-Branco Levamisole as a Strategy Against Bacteria from Canine Otitis Externa: An In Vitro Evaluation Veterinary Sciences canine external otitis bacteria biofilms levamisole |
| title | Levamisole as a Strategy Against Bacteria from Canine Otitis Externa: An In Vitro Evaluation |
| title_full | Levamisole as a Strategy Against Bacteria from Canine Otitis Externa: An In Vitro Evaluation |
| title_fullStr | Levamisole as a Strategy Against Bacteria from Canine Otitis Externa: An In Vitro Evaluation |
| title_full_unstemmed | Levamisole as a Strategy Against Bacteria from Canine Otitis Externa: An In Vitro Evaluation |
| title_short | Levamisole as a Strategy Against Bacteria from Canine Otitis Externa: An In Vitro Evaluation |
| title_sort | levamisole as a strategy against bacteria from canine otitis externa an in vitro evaluation |
| topic | canine external otitis bacteria biofilms levamisole |
| url | https://www.mdpi.com/2306-7381/12/7/640 |
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