What drives antimicrobial prescribing for companion animals? A mixed-methods study of UK veterinary clinics

Antimicrobial use in companion animals is a largely overlooked contributor to the complex problem of antimicrobial resistance. Humans and companion animals share living spaces and some classes of antimicrobials, including those categorised as Highest Priority Critically Important Antimicrobials (HPCIAs). Veterinary guidelines recommend that these agents are not used as routine first line treatment and their frequent deployment could offer a surrogate measure of ‘inappropriate’ antimicrobial use. Anthropological methods provide a complementary means to understand how medicines use makes sense ‘on-the-ground’ and situated in the broader social context

Survey of systemic antimicrobial prescribing for dogs by Victorian veterinarians

Objective: Investigate the current antimicrobial prescribing patterns of veterinarians in Victoria for dogs and compare these results to patterns described 20 years ago. Methods: A questionnaire was sent to 1380 veterinarians in Victoria. The first section collected demographic information of respondents. The second and third sections evaluated respondents’ approach to use of antimicrobial drugs for scenarios in dogs in which ‘clinical evidence suggests bacterial infection is the likely cause’ and where ‘it is unknown whether bacterial infection plays a role’. The final section evaluated respondents’ approach to use of antimicrobial drugs during dental extraction in a dog. Results: Of the 1380 veterinarians who were contacted, 259 responses were received (response rate 19%). Of these respondents, 95% (246/259) completed their veterinary degree at the University of Melbourne. The ratio of female to male respondents was 2.1 : 1 (171 : 82) and of urban to rural respondents was 1.9 : 1 (159 : 85). Drug selection for some scenarios was open to criticism. For example, to treat chronic prostatitis 16% (42/259) of respondents selected amoxicillin-clavulanate even though it has poor penetration of prostatic tissues. Some prescribing choices have changed since 1997; for example, for acute tracheobronchitis, 36% (73/204) of respondents indicated they would use antimicrobials, compared with 87% of respondents in 1997. For the treatment of idiopathic vestibular disease, only 5% (10/197) of respondents in the current study versus 45% (294/654) in the 1997 survey opted to use antimicrobials. Conclusion: Antimicrobial drug selection for treatment of dogs by registered veterinarians in Victoria was generally consistent with recent recommendations, although some details were widely variable

Intramembrane cavitation as a unifying mechanism for ultrasound-induced bioeffects

The purpose of this study was to develop a unified model capable of explaining the mechanisms of interaction of ultrasound and biological tissue at both the diagnostic nonthermal, noncavitational (<100 mW·cm−2) and therapeutic, potentially cavitational (>100 mW·cm−2) spatial peak temporal average intensity levels. The cellular-level model (termed “bilayer sonophore”) combines the physics of bubble dynamics with cell biomechanics to determine the dynamic behavior of the two lipid bilayer membrane leaflets. The existence of such a unified model could potentially pave the way to a number of controlled ultrasound-assisted applications, including CNS modulation and blood–brain barrier permeabilization. The model predicts that the cellular membrane is intrinsically capable of absorbing mechanical energy from the ultrasound field and transforming it into expansions and contractions of the intramembrane space. It further predicts that the maximum area strain is proportional to the acoustic pressure amplitude and inversely proportional to the square root of the frequency () and is intensified by proximity to free surfaces, the presence of nearby microbubbles in free medium, and the flexibility of the surrounding tissue. Model predictions were experimentally supported using transmission electron microscopy (TEM) of multilayered live-cell goldfish epidermis exposed in vivo to continuous wave (CW) ultrasound at cavitational (1 MHz) and noncavitational (3 MHz) conditions. Our results support the hypothesis that ultrasonically induced bilayer membrane motion, which does not require preexistence of air voids in the tissue, may account for a variety of bioeffects and could elucidate mechanisms of ultrasound interaction with biological tissue that are currently not fully understood