Agrisearch (United Kingdom)

Background: The use of iodine is a controversial issue even though it has been used in wound management for over 150 years. There is a large amount of published literature available for both povidone and cadexomer iodine although the results are often conflicting due to the large array of different preparations used and different study types employed.Objectives: This literature review concentrates on the use of povidone and cadexomer iodine. The review highlights their antimicrobial efficiency, the issue of bacterial resistance, and effects on tissue and cells involved in wound healing. Toxicity and adverse reactions associated with these antimicrobial agents are also considered.Major findings: The literature supports the use of povidone and cadexomer iodine as effective antimicrobial agents that bacteria have not developed resistance to. Other findings noted that povidone and cadexomer iodine should be used with caution and at decreased concentrations in patients with extensive burns and systemic complications such as renal failure, thyroid dysfunction, and other severely immunocompromised patients.Conclusions: The literature supports the use of povidone and cadexomer iodine in wound care for its effects on tissue and cells, especially in newer formulations. Cadexomer iodine has proven to be very effective in chronic wounds while povidone iodine has been noted to be more effective in infected acute wounds. Gaps in the research have been identified as a lack of clear evidence comparing new formulations of povidone iodine to traditional preparations. It is clear that more research evidence is required for clinicians who routinely use these antimicrobial agents in wound management.

To measure the residues of spinosad and chlorhexidine in the tissues of sheep after treatment of blowfly strike. Fourteen sheep with natural myiasis and 12 with artificial infestations of Lucilia cuprina larvae had the wool removed over their infestations and were treated with an aerosol wound dressing containing spinosad and chlorhexidine. Sheep were killed up to 14 days after treatment and residues of the chemicals measured in tissues. Chlorhexidine was not detected in any tissue. Residues of spinosad were highest in fat, lowest in muscle and intermediate in liver and kidney. The highest residue detected was 0.2 mg/kg spinosad in perirenal fat 7 days after generous treatment of a sheep with a large fly strike. Residues of spinosad in fat peaked 3 to 7 days after treatment and 1 to 3 days after treatment in liver and kidney. These studies present a realistic worst-case in struck sheep and at the highest dose studied, equivalent to 5.8 mg spinosad per kg body weight, the maximum residue detected of 0.2 mg/kg in peri-renal fat was 20% of the Australian maximum residue limit. Muscle, liver and kidney residues of spinosad were also below the Australian maximum residue limits at all times.

A survey of farms in northern New South Wales and southeastern, central, western and northern Queensland was conducted to determine levels of insecticide resistance in populations of buffalo fly Haematobia irritans exigua. A field bioassay using discriminating concentrations of 10 insecticides commonly used for buffalo fly control was used. Resistance to all synthetic pyrethroids tested (cypermethrin, deltamethrin, cyhalothrin, flumethrin and cyfluthrin) was common and widespread in coastal zones, but was lower in inland zones. In contrast, there was no resistance to the organophosphate diazinon and only low levels of resistance to ethion and chlorfenvinfos. Synergism between piperonyl butoxide and cypermethrin was demonstrated.