In vitro efficacy of a polyhexamethylene biguanide-impregnated gauze dressing against bacteria found in veterinary patients.
OBJECTIVE
To evaluate the in vitro efficacy of polyhexamethylene biguanide (PHMB)-impregnated gauze dressing in limiting the growth of bacteria both within and underneath the dressing.


METHODS
In vitro study.


METHODS
Squares of PHMB-impregnated and control gauze were placed on agar plates inoculated with 1 of 11 bacterial species, including 8 multi-resistant organisms. Growth under the gauze was assessed qualitatively after 24-hour incubation. Repeated use of sponges was used to evaluate residual inhibitory activity against Micrococcus lutea and Staphylococcus schleiferi ss. schleiferi. In a second procedure, PHMB-impregnated and control gauze squares were placed in sterile plastic wells and inoculated with 1 of 5 bacterial species, including Pseudomonas spp. and Klebsiella spp. Inhibition of bacterial growth within and underneath the dressing after 24-hour incubation was evaluated by quantifying the numbers of bacteria on the well floor and within each square.


RESULTS
PHMB-impregnated gauze provided greater inhibition of growth of 4/4 Gram-positive species and 2/6 Gram-negative species on inoculated plates compared with control gauze. Residual inhibitory activity of PHMB-impregnated gauze was significantly greater against M. lutea on all days and against S. schleiferi ss. schleiferi on days 1 and 4 compared with control. No bacteria were recovered from inoculated PHMB-impregnated gauze squares placed in sterile wells or from the well floor underneath. More than 9 x 10(5) colony-forming units (CFU) were recovered from inoculated control samples placed in sterile wells and more than 8.4 x 10(4) CFU were recovered from control well floors.


CONCLUSIONS
PHMB-impregnated gauze dressing, when placed on inoculated agar plates, reduces growth of underlying bacteria, particularly Gram-positive species. Wet-inoculated PHMB-impregnated dressing prevents growth of Gram-positive and Gram-negative bacteria both within and underneath the dressing.


CONCLUSIONS
PHMB-impregnated dressings may be useful for reducing contamination of underlying wounds by bacterial pathogens.
Lee
William R
WR
Department of Small Animal Clinical Sciences, University of Tennessee College of Veterinary Medicine, Knoxville, TN 37996-4544, USA.
Tobias
Karen M
KM
Bemis
David A
DA
Rohrbach
Barton W
BW
D000818:Animals; D001458:Bandages / Q000382:microbiology*; D001645:Biguanides / Q000008:administration & dosage / Q000494:pharmacology*; D002371:Cat Diseases / Q000517:prevention & control; D002415:Cats; D004202:Disinfectants / Q000008:administration & dosage / Q000494:pharmacology*; D004283:Dog Diseases / Q000517:prevention & control; D004285:Dogs; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D014946:Wound Infection / Q000517:prevention & control / Q000662:veterinary
D001645:Biguanides; D004202:Disinfectants; C031233:polihexanide