Inconsistent and multiple bacterial species from different sample types of dogs with urolithiasis and bacterial cystitis

Abstract

Urinary tract infection is the most common complication found in dogs with urolithiasis. Bacterial cystitis can play an important role in dogs with urolithiasis; it can either be the cause of cystic formation or be a complication following urolithiasis. Moreover, urolithiasis cases that come with bacterial cystitis can lead to a condition of complicated cystitis which will require more complicated treatment and management. Proper bacterial identification should be performed in order to follow an appropriate treatment. Specific treatments require bacterial identification in order to select the most appropriate antibiotics. There are three main possible sites for bacterial sample collection in bacterial cystitis cases (urine, uroliths and urinary bladder mucosa), while the most representative sample is still questionable. In this study, urine, urinary bladder mucosa from the body and the neck and urolith were collected from ten dogs with bacterial cystitis and urolithiasis. All dogs were firstly diagnosed for all types of urolithiasis which needed to undergo surgical treatment at the Surgery Unit, Small Animal Teaching Hospital, Faculty of Veterinary Science, Chulalongkorn University. Urinalysis and urine sediment cytology were then performed to confirm the condition of bacterial cystitis in all samples. In the surgery field, all samples were cultured for bacterial species identification by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF). Uroliths retrieved from the surgical procedure were submitted for stone analysis at the Minnesota Urolith Center, College of Veterinary Medicine, University of Minnesota, USA. Positive bacterial culture results from urolith, urine (>103 CFU/mL), mucosa from the body of the bladder and mucosa from the neck of the bladder were 90%, 87.5% (no data available in 2 patients), 50%, and 40% respectively. The most common bacteria cultured from UTI patients in this study were Escherlichia coli and Pseudomonas aeruginosa. In conclusion, urine culture should be done in every patient either prior to or in the surgical field. Moreover, due to the result of inconsistent bacterial culture and bacterial species from some types of samples, a urolith culture is recommended as the appropriate culture in case of a negative result from a urine culture.