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In vitro efficacy of a 0.2% polyhexamethylene biguanide‐impregnated gauze dressing against pathogenic bacterial isolates found in horses
Author(s) -
Noll Charlene V.,
Kilcoyne Isabelle,
Nieto Jorge E.,
Thio Timothy,
Byrne Barbara A.
Publication year - 2021
Publication title -
veterinary surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 79
eISSN - 1532-950X
pISSN - 0161-3499
DOI - 10.1111/vsu.13626
Subject(s) - medicine , biguanide , microbiology and biotechnology , agar , bacterial growth , agar plate , staphylococcus aureus , bacteria , pseudomonas aeruginosa , gentamicin , veterinary medicine , antibiotics , biology , genetics , metformin , insulin
Objective To determine the ability of 0.2% polyhexamethylene biguanide (PHMB)‐impregnated gauze to inhibit the growth of bacteria isolated from equine infected sites. Study Design In vitro study. Methods Nine bacterial isolates were obtained from cultures submitted from equine patients presenting with penetrating injuries of the hoof ( n = 4), septic osteitis ( n = 1), synovial sepsis ( n = 1), wounds ( n = 2), and incisional infection following laparotomy ( n = 1). Two standardized strains were also included. A standard inoculum of each isolate was placed on 12 Muller–Hinton agar plates. Squares (2.5 cm × 2.5 cm) of 0.2% PHMB‐impregnated ( n = 6) and nonimpregnated control gauze ( n = 6) were placed on inoculated agar plates. Bacterial growth under each gauze square was assessed after a 24‐h incubation period and areas of inhibition were measured to a standardized scale, using image‐processing software. Mean ± SD growth inhibition (%) using 0.2% PHMB‐impregnated gauze was compared to the nonimpregnated gauze for each isolate using Student's t test ( p < .05). Results The 0.2% PMHB ‐impregnated gauze inhibited the growth of Staphylococcus spp. ( n = 4) by 33%–83.1% and that of Escherichia coli spp. ( n = 4) by 6.5%–37%. There was no inhibition of growth of Pseudomonas aeruginosa or either Enterococcus spp. Conclusion The 0.2% PHMB‐impregnated dressing tested here inhibited the growth of staphylococcal and E. coli isolates, but the magnitude of inhibition varied between strains. Clinical Relevance These results justify in vivo studies to evaluate the ability of the dressing to reduce the bacterial growth of common equine bacterial pathogens in clinical practice.