BACKGROUND: Meticillin-resistant Staphylococcus aureus (MRSA) and meticillin-resistant Staphylococcus pseudintermedius (MRSP) infections are increasingly reported in dogs, and these bacteria may be isolated from ear infections. HYPOTHESIS/ OBJECTIVES: The main aim of the present study was to investigate the in vitro antimicrobial activity of miconazole, polymyxin B and a combination of both against 24 canine MRSA and 50 canine MRSP isolates. The minimal inhibitory concentration (MIC) values of 12 other antimicrobial agents were also determined. METHODS: All MIC values were determined according to a broth microdilution assay. RESULTS: Acquired resistance was found to all tested agents, except for linezolid, miconazole and polymyxin B. The MIC values for miconazole and polymyxin B against MRSA were in the range of 4-8 and 8-64 μg/mL, respectively, while the MIC values for miconazole and polymyxin B against MRSP were in the range of 1-2 and 0.25-4 μg/mL, respectively. Using a combination of miconazole and polymyxin B, there was no evidence for enhanced in vitro activity of the combination (i.e. synergy) of both products. Nevertheless, MIC(90) values of the combination of these antimicrobial agents and of a commercial product containing both agents were at least 1000 times lower than the concentration present in the commercial product. CONCLUSIONS AND CLINICAL IMPORTANCE: These results indicate that the topical use of a combination of miconazole and polymyxin B in a 43.5:1 ratio may have potential for the treatment of MRSA-mediated and MRSP-associated otitis externa in dogs.
BACKGROUND:Meticillin-resistant Staphylococcus aureus (MRSA) and meticillin-resistant Staphylococcus pseudintermedius (MRSP) infections are increasingly reported in dogs, and these bacteria may be isolated from ear infections. HYPOTHESIS/ OBJECTIVES: The main aim of the present study was to investigate the in vitro antimicrobial activity of miconazole, polymyxin B and a combination of both against 24 canine MRSA and 50 canine MRSP isolates. The minimal inhibitory concentration (MIC) values of 12 other antimicrobial agents were also determined. METHODS: All MIC values were determined according to a broth microdilution assay. RESULTS: Acquired resistance was found to all tested agents, except for linezolid, miconazole and polymyxin B. The MIC values for miconazole and polymyxin B against MRSA were in the range of 4-8 and 8-64 μg/mL, respectively, while the MIC values for miconazole and polymyxin B against MRSP were in the range of 1-2 and 0.25-4 μg/mL, respectively. Using a combination of miconazole and polymyxin B, there was no evidence for enhanced in vitro activity of the combination (i.e. synergy) of both products. Nevertheless, MIC(90) values of the combination of these antimicrobial agents and of a commercial product containing both agents were at least 1000 times lower than the concentration present in the commercial product. CONCLUSIONS AND CLINICAL IMPORTANCE: These results indicate that the topical use of a combination of miconazole and polymyxin B in a 43.5:1 ratio may have potential for the treatment of MRSA-mediated and MRSP-associated otitis externa in dogs.
Authors: Konstantin Andreev; Michael W Martynowycz; Mia L Huang; Ivan Kuzmenko; Wei Bu; Kent Kirshenbaum; David Gidalevitz Journal: Biochim Biophys Acta Biomembr Date: 2018-04-03 Impact factor: 3.747
Authors: Ryan Kean; Ranjith Rajendran; Jennifer Haggarty; Eleanor M Townsend; Bryn Short; Karl E Burgess; Sue Lang; Owain Millington; William G Mackay; Craig Williams; Gordon Ramage Journal: Front Microbiol Date: 2017-02-23 Impact factor: 5.640
Authors: Sergey V Kravchenko; Pavel A Domnin; Sergei Y Grishin; Alexander V Panfilov; Viacheslav N Azev; Leila G Mustaeva; Elena Y Gorbunova; Margarita I Kobyakova; Alexey K Surin; Anna V Glyakina; Roman S Fadeev; Svetlana A Ermolaeva; Oxana V Galzitskaya Journal: Int J Mol Sci Date: 2022-01-04 Impact factor: 5.923
Authors: Piotr Szweda; Marta Schielmann; Aneta Frankowska; Barbara Kot; Magdalena Zalewska Journal: J Vet Med Sci Date: 2013-11-11 Impact factor: 1.267