A recent study (1) shows a worrying number of highest
priority critically important antimicrobial agents (HPCIA) prescriptions in
cats in UK, compared with dogs (39.2% versus 5.4%). The most frequently
prescribed antibiotic in cats is cefovecin (36.2%).
This antimicrobial has been
included in the HPCIA by the World Health Organisation (WHO) (2). Its importance is related to the
therapy of acute bacterial meningitis and disease due to Salmonella in
children and infections due to MDR Enterobacteriaceae, which are
increasing in incidence. The WHO also warns us that “resistance may result from
transmission of Enterobacteriaceae, including E. coli and Salmonella,
from non-human sources.”
There are two uses in
cats described on Convenia’s EU-data sheet:
1) Treatment of skin
and soft tissue abscesses and wounds associated with specific bacterias.
Cat fight- abscesses may lead to multi-organ system failure
as a consequence of septic shock or bacterial toxins. Anaerobes are most frequently
isolated in abscesses (3) and cefovecin effect on these is poor (4). FECAVA
antibiotic prescription guidelines recommends amoxicillin- clavulanic acid or
clindamycin as empirical treatment of abscesses (5). Nowadays amoxicillin-clavulanic
acid is available in palatable tables and clindamycin can be found in liquid
form. It is also useful to remind ourselves that sometimes these abscesses can
be managed with drainage and chlorhexidine flushing alone.
Bacterial pyoderma had been historically considered a rare
finding in cats, possibly due to decreased bacterial adherence to corneocytes
(6). A recent study (7) showed that feline pyoderma is not that uncommon,
although its prevalence is still low when compared to dogs. In this study feline pyoderma was frequently
linked to underlying hypersensitivities, which need to be treated to effectively
fight the pruritus (8). A significant part of these cats do not respond to
antibiotic treatment. On the other hand, cytological criteria to guide
diagnosis are not well defined (7), lesions are unspecific and treatment of
feline pyoderma is frequently prescribed without previous cytology in first opinion
practice. It would be interesting to find out how often we prescribe this
antibiotic in cases of low bacterial risk.
2) Urinary tract
infections (UTI) caused by E. Coli
and Proteus.
Cefovecin is not active against Pseudomonas pp. or Enterococci
and the latter are third in importance after E. Coli and Staphylococcus in
feline UTI (9,10).
Bacterial cystitis is only present in a low percentage
(2-12%) of young cats with urinary tract symptoms. In older cats and cats with
predisposing diseases the prevalence of bacterial cystitis may be twice as much
as in younger individuals (5). Feline idiopathic cystitis is responsible for a
great number of low urinary tract disorders (FLUTD) in cats and should be
considered first in our list of differential diagnosis.
The guidelines (5) recommend aminopenicillins for UTI
treatment initiated before results are available, and amoxicillin/clavulanate
in pyelonephritis. In-house tests can be used to achieve prompter culture and
sensitivity results.
SOME PROPERTIES OF
CEFOVECIN THAT WE DO NOT ALWAYS REMEMBER:
1) Renal elimination, but a small
amount is eliminated unchanged in the bile. It needs to be used with caution
in animals with renal dysfunction and avoided when the dysfunction is severe
(11). Conserations:
o Decrease dose when CREA 2.5-3.5
mg/d (221-309 mmol/L)
§ Standard dose x
(normal sCREA/cat sCREA)
§ Reduce dosing interval: CatsCREA/
normal sCREA
2) Because the drug can persist in the
body for up to 65 days, adverse reactions may occur that require prolonged
treatment. Some specific adverse effects have been described in cats (11):
odd behaviour, vocalisation, inappropriate urination, haemolytic anaemia and
elevated BUN and serum creatinine.
3) The long duration of excretion in
the urine makes it difficult to interpret post-treatment culture results.
4) Although clinical significance has
not been established, it may compete with other highly protein-bound drugs
for plasma protein binding sites: furosemide, doxycycline, and ketoconazole,
NSAIDs, propofol, cardiac, anticonvulsant, and behavioral medications.
5) Light sensitive.
6) Cefovecin may cause positive
Coomb’s test, positive serum/urine creatinine (Jaffa) and urinary glucose
(Clinitest).
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On the study by Singleton’s et al, the main presenting
complaints more likely to be associated with antibiotic prescription included
respiratory conditions, trauma, tumours and kidney disease.
Let us have a look at the most common bacterial isolates in
cats (12):
-
Systemic
infections:
o
Neutropenia E.
coli, Enterococcus spp.,
anaerobes
o
Systemic inflammatory response
syndrome E. coli
-
Respiratory
tract:
o
Upper respiratory tract infections: Mycoplasma spp., Chlamydophila felis,
or Bordetella bronchiseptica.
o
Pneumonia Mycoplasma
spp.
o
Pyothorax Pasteurella
spp., anaerobes
-
Pyelonephritis E. coli, Enterococcus spp.
-
Cholangitis/Hepatitis Escherichia
coli, Enterococcus spp.,
anaerobes.
Amoxicillin-clavulanic acid and doxycycline were reported to
be more efficacious than cefovecin in shelter cats with clinical signs
consistent with upper respiratory disease (13). Its high protein-binding does
not allow it to achieve effective serum levels to treat systemic E. Coli
infections (14). As discussed above, administration of this antimicrobial in
cases of renal dysfunction should be carefully handled.
So it seems like Cefovecin is overprescribed in cats, despite
the fact that its long duration of action involves a potentially higher risks of
adverse effects including the development of bacterial antimicrobial
resistance.
International Cat Care tries to
address the difficulties found in cats when oral treatment is administered by
describing restraining techniques and providing a list of options such as pill
crushers, gelatine capsules, pill splitters and pill givers. Detailed
instruction can be found on their web site: https://icatcare.org/advice/how-give-your-cat-tablet
Besides that, there are a few
antibiotics available which make administration easier and more palatable (e.g:
Zodon (liquid clindamycin), Synulox palatable tablets) as well as
treats to wrap drugs up (Easypill).
References:
- Singleton, D.A. et al.
Patterns of antimicrobial agent prescription in a sentinel population of
canine and feline veterinary practices in the United Kingdom. The Veterinary Journal, 224(June),
pp. 18-24 2017
- Critically important antimicrobials for human medicine – 5th
rev. Geneva: World Health Organization; 2017.
- Love et al Bacteriological
warfare amongst cats: what have we learned about cat bite infections? Veterinary Microbiology 74
179-193 2000
- Wiebe, V. Drug Therapy for Infectious Diseases of
the Dog and Cat. Table 3.1. Section A: Pharmacology guidelines.
Chapter 4: Approaching infectious
diseases cases p 3 Ed:
Wiley-Blackwell 2015
- FECAVA/Danish Small Animal
Veterinary Association Antibiotic
Use Guidelines for Companion Animal Practice. Chapter 6: Organ and
disease specific recommendations 2009
- Woolley, K.L.; Kelly,
R.F.; Fazakerley, J.; Williams, N.J.; Nuttall, T.J.; McEwan, N.A. Reduced
in vitro adherence of Staphylococcus species to feline corneocytes
compared to canine and human corneocytes. Vet. Dermatology. 19, 1–6 2008,
- YU H. W. and Vogelnest L.
J. Feline superficial pyoderma: a retrospective study of 52 cases
(2001-2011) Veterinary dermatology
p1-10 2012
- Diesel, A. Cutaneous
hypersensitivity dermatoses in the feline patient: a review of allergic
skin disease in cats Veterinary
Science 4(2), 25 2017
- Marques et al. European
multicenter study on antimicrobial resistance in bacteria isolated from
companion animal urinary tract infections. Veterinary Research 12:213 2016
- Litster A, Moss S, Platell
J et al.: Occult bacterial lower urinary tract infections in cats -
urinalysis and culture findings. Veterinary
Microbiology 136(1-2):130-134, 2009
- Katrina R. Viviano. Chapter 4: Practical Antimicrobial
Therapy. Consultations in Feline
Internal Medicine Vol 7 edited by S.E Little. Ed Elsevier p57 2016
- Maddison J, Page S, Church
D. Clinical Conditions in Cats
Associated with Bacterial Infections and the Most Common Bacterial
Isolates to Guide Empirical Antimicrobial Therapy Small animal clinical
pharmacology, Edinburgh, Saunders. 2008
- Litster AW: Comparison of
the efficacy of amoxicillin-clavulanic acid, cefovecin and doxycycline in
the treatment of upper respiratory disease in cats housed in animal
shelters. Am Vet Med Assoc
241:218-226, 2012
- Wiebe, V. Drug Therapy for Infectious Diseases of
the Dog and Cat. Section D:
Antibiotics Chapter 135: Cefovecin
p 136 Ed: Wiley-Blackwell 2015
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