Clinical signs
There are no clinical markers to distinguish between
MRSP and MSSP. The clinical presentation is the same as for other pyodermas. We
distinguish between:
·
Surface (intertrigo,
‘hot spots’)
·
Superficial (bacterial
folliculitis, impetigo, muco-cutaneous pyoderma, superficial-spreading
pyoderma)
·
Deep pyoderma (furunculosis,
pododermatitis with granulomas, lick granuloma, callus pyoderma)
Lesions include: papules, pustules, erythema,
hyperpigmentation, alopecia, scaling and collarets for superficial lesions and
fistulas, nodules and bullae for deep infections. Additionally, MRSP can be
found in otitis cases.
A resistant bacteria is usually suspected if:
·
The lesions improved
less then 50% within 2 weeks of antibiotic treatment
·
If new lesions develop
during antibiotic treatment
·
If despite 6 weeks of
antibiotic treatment, lesions are still present
·
If intracellular rods
are found on cytology
·
Prior history of drug
resistant infection in the household pets
Diagnosis
A correct early diagnosis of a MRSP infection is
essential, as one can then start implementing measures to prevent bacterial transmission
to other beings and to the environment (MRSP can persist in the environment for
months) and select the proper therapeutic regime. Before performing a culture, a
cytological examination should be always performed to visualize the bacteria
(rods, cocci) or other infectious agents (fungi). If the culture comes back
negative, but we have seen bacteria in the cytology one has to repeat the
cultures (if still clinical signs).
The material for the culture can be obtained with
swabs (erosions, pustules) and skin biopsies if the lesions are deep (in this
case the overlying surface should be disinfected and a 4-6mm punch taken,
before putting the material in the culture medium, the intact epidermis should
be eliminated to avoid surface contaminants).
The material should be sent to the lab, which then
performs cultures and susceptibility tests (Kirby Bauer disc diffusion test
and/or minimum inhibitory concentrations). To further characterize the bacteria
and their resistance pattern, the following tests can be performed: PBP2a latex
bead agglutination test, mecA PCR, SCCmec typing, D-test (for inducible
clindamycin resistance), … If the animals were or are currently on antibiotics
the lab should be informed about this situation and the used antibiotic, to
implement measures to prevent false negative results (the lab can then enrich
and/or prolong the cultures as the bacteria may be less ‘vital’ due to used
antibiotics).
Treatment
The treatment follows the same principles as for
susceptible infections. Its success depends on the bacteria (susceptibility),
severity of lesions, pet and owner compliance and on the underlying primary
disease.
It is important to eliminate the bacteria and prevent
their spread as soon as possible, therefore a combination therapy consisting of
shampoos (chlorhexidin, benzoyl peroxide, ethyl lactate) and systemic treatment
should be combined whenever possible for generalized disease. For focal lesions
antibacterial shampoos or creams (mupirocin, fucidic acid) can be used.
Problems with topical therapy include poor owner compliance, poor penetrations
in deeper tissues, biofilm formation and resistance.
The antibiotic use should depend on the sensitivity
results, some MRSP are multi-drug resistant as they can acquire or express more
then one resistance gene. Often MRSP maybe be susceptible to the following
antibiotics: chloramphenicol, trimethoprim/sulfamethoxazole, amikacin, fucidic
acid, doxycycline.
Antibiotics such as vancomycin, teicoplanin, linezolid
are exclusively reserved for treatment of humans infected with multi-resistant
MRSA.
Prevention
Each practice should utilize special prevention measures
for cases of resistant infection (appropriate owner education, hygiene measures,
restricted antibiotics use).
Zoonotic potential
There are reports of MRSP carriage in owners of dogs
which were infected with MRSP (same strain) or in veterinarians and veterinary personnel.
Human infections are very rare, but possible (attention to immune-suppressed
animal owners and care-takers).
References
-
Linek M. Proceedings of the 27th Annual congress of the ESVD-ECVD 2014,
p114-118.
-
Hillier A et al. Guidelines for the diagnosis and antimicrobial therapy of canine
superficial bacterial folliculitis (Antimicrobial Guidelines Working Group of the International Society for
Companion Animal Infectious Diseases). Vet Dermatol.
2014 Jun;25(3):163-75
-
Beco L et al. Suggested guidelines for using systemic antimicrobials in
bacterial skin infections (1): diagnosis based on clinical presentation,
cytology and culture. Vet Rec. 2013 Jan 19;172(3):72-8.
-
Beco L et al. Suggested guidelines for using systemic antimicrobials in
bacterial skin infections: part 2 antimicrobial choice, treatment regimens and
compliance. Vet Rec. 2013 Feb 9;172(6):156-60
-
Bannoehr J, Guardabassi L.
Staphylococcus pseudintermedius in the dog: taxonomy, diagnostics, ecology,
epidemiology and pathogenicity. Vet dermatol 2012 Aug;23(4):253-66
