Presenter – Sheri Ross DVM PhD DACVIM from the University of California Companion Animal Hemodialysis Unit
The over diagnosis of cats with urinary tract infections (UTI’s) happens all too frequently and with antibiotic resistance being of increasing concern, last week’s veterinary webinar organised by ‘The Webinar Vet’ made essential viewing.
Sheri Ross DVM PhD DACVIM from the University of California, kindly stepped out of her hectic schedule to offer us an hour of her time discussing the diagnosis and pathogenesis of UTIs in cats.
Sheri started the lecture by citing two cases with exactly the same clinical signs and urinalysis results. Both had dysuria, haematuria and inappropriate voiding of urine. Urinalysis revealed a specific gravity of 1.020, the presence of blood and protein with cytology demonstrating the occasional cocci. The only difference between these two cats was their age, one being 12 years old and the other being one year old. The age difference could be extremely helpful in obtaining a diagnosis for each. According to studies, of the cats suffering from FLUTD between the age of 1 to 10 years, 50% will have feline idiopathic cystitis and only 2 % will have a UTI. However in cats older than 10 years, 46% will have a UTI, 22% will have neoplasia and only 5 % will have feline idiopathic cystitis. Sheri’s point was to highlight that if an older cat presents with FLUTD, alarm bells should ring and further diagnostics should be performed to look for a UTI and other underlying causes.
Both cats had some cocci present on urinalysis but Sheri was keen to stress that the presence of bacteria doesn’t always mean the cats are suffering from a UTI. The presence of a large number of bacteria alongside wbcs would be more suspicious and a culture and sensitivity should always be performed. The presence of multi types of bacteria tends to indicate the sample is likely to have been contaminated as usually there is only one pathogen present in cats with a UTI.
Sheri advised we took care in our use of antibiotics prior to getting a diagnosis. With the use of sustained release injectable antibiotics common place amongst cats, many samples could come up negative on culture. The antibiotics render the bacteria non-viable at the time of culture even though they not potent enough to cure the infection. Also, once culture and sensitivity results are obtained it is wise to remember these results are only relevant in an in vitro situation and may not cross over to the in vivo ‘patient’. For example Sheri advised if a culture was positive for enterococcus she could predict that the UTI would be resistant to antibiotics such as Cephalosporins because of the infection’s location even if the bacteria are sensitive to Cephalosporins on culture and sensitivity.
This was another session of incredibly helpful veterinary CPD brought to us by The Webinar Vet. Sheri needlessly apologized for this webinar’s coverage of a UTI’s pathogenesis as she felt this was perhaps not the most interesting of subjects. However she really needn’t have worried as it was all fascinating and I can’t wait to tune into next week’s webinar, Feline UTI’s – part 2.
The Stethoscope (MRCVS)