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 25-28 September, 2018 | Singapore
When to culture for MRSP? Modified from Hillier et al, 2014
and allergens from the skin
· Restore normal skin structure and function against infections
· Control against reinfections when underlying disease is being investigated and managed
· Reduce environmental contamination
· Reduce risk of transmission to other dogs and hu-
Topical antibacterial options include 2-3% chlorhexidine, benzoyl peroxide, bleach (sodium hypochlorite), miconazole, fusidic acid, mupirocin, triclosan, bacitracin and polymixin B. They are available in shampoos, conditioners, lotions and sprays for more generalised infections, and creams, lotions, gels and wipes for more localised infections.
Systemic antibiotic
These are indicated for generalised, severe or deep bacterial pyoderma, if the dog is not amendable to topical therapy or owner unable to perform topical therapy. The results of antibiotic susceptibility testing guide the veterinarian in antibiotic selection. The final choice of antibiotic would depend on several factors including availability, safety, costs and patient factors (e.g. concurrent disease or drug therapy, drug reactions). Guidelines for selecting antibiotic and their doses have been published (Hillier et al, 2014) and will be discussed during the presentation.
· Superficial bacterial pyoderma: 3 weeks or 1 week beyond clinical resolution
· Deep bacterial pyoderma: 4-6 weeks or 2 weeks beyond clinical resolution
· If treatment duration is less than 3 weeks, then the patient should be examined prior to stopping antibi- otics to ensure resolution of infection
Controlling against reinfections
Bacterial pyoderma is always secondary to underlying diseases. Veterinarians play an important role in identifying and managing these underlying diseases
so that we can avoid reinfections, repeated antibiotic treatments and reduce risks of development of antibiotic resistance.
Fortunately, there is no difference in treatment outcomes between dogs treated for MSSP and MRSP with both groups having an overall good prognosis. Dogs can continue to carry MRSP for more than one year after clinical resolution of infection. These dogs can pose
a risk to susceptible in contact animals (both dogs and cats) and humans, as well as contaminating the environment.
Transmission to in contact dogs and owners Staphylococcus pseudintermedius do not typically
colonise humans although we can betransient
· Less than 50% improvement in lesions within 2 weeks of appropriate systemic antimicrobial therapy
· Appearance of new lesions consistent with bacterial pyoderma 2 or more weeks after starting appropriate systemic antimicrobial therapy
· Presence of residual lesions and cytological evi- dence of bacterial pyoderma after 6 weeks of appro- priate systemic antimicrobial therapy
· Prior history of multidrug resistant infection in affect- ed dog or from in contact dog in same household
· Recent history of hospitalisation
· Breeding dogs?
Bacterial culture collection and antibiotic susceptibility testing
A culture swab is used to collect samples from the surface and superficial lesions. Primary lesions such as intact pustules are preferred over secondary lesions such as epidermal collarettes and crusts. For deeper lesions such as nodules and draining tracts, the skin surface should be surgically prepared and a deep tissue biopsy collected for bacterial culture and antibiotic susceptibility testing.
Antimicrobial susceptibility testing is most commonly performed using the disk diffusion or dilution methods. While methicillin resistance is identified using oxacillin antibiotic testing, the gold standard to diagnose methicillin resistance is polymerase chain reaction
(PCR) detection of mecA gene. When there is a clinical suspicion for MRSP, the author request for an extended panel of antibiotics including oxacillin. This is because some MRSP may show apparent in vitrosusceptibilities to beta lactams i.e. cephalexin and amoxicillin-clavulanate acid but are ineffective in vivo.
Duration of treatment
Key steps for successful treatment of bacterial pyoder- ma
· Correct diagnosis of pyoderma
· Use topical antibacterial therapy and if necessary
select an appropriate systemic antibiotic
· Correct antibiotic administration i.e. correct dose and frequency until clinical cure
· Diagnosing and treating any underlying disease(s) causing bacterial pyoderma
Treatment considerations
Topical antibacterial therapy
The skin lesions are readily accessible to topical therapy. Topical antibacterial therapy can be effective as a sole treatment against surface and superficial bacterial pyoderma regardless of methicillin susceptibility.
· May avoid the need for systemic antibiotics
· More rapid resolution of infection
· Reduce duration of systemic antibiotics required
· Break up biofilms, remove crusts, debris, bacteria
Benefits of topical antibacterial therapies

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