This study investigated prevalence of different bacterial species in cats with urinary tract infections.The most  common isolate was Escherichia coli(37.3%) followed by Enterococcus faecalis (27%).Almost 20% of isolates  were coagulase-negative species that could not be identified with standard methods.Further testing identfied them as Staphylococcus felis.The S felis-positive samples were collected by cystocentesis from cats with  clinical signs of urinary tract disease. S felis was significantly associated with higher urine specific gravity and  urine that was more likely to contain crystals.The authors believe this to be the first published study that associates S felis with clinical signs of lower urinary tract disease in cats. S felis may be a common urinary  pathogen of cats, but further work is required for confirmation. This study suggests that if a gram-negative organism is seen in cats with urinary tract infections, it is probably E coli. If gram-positive cocci are seen, E  faecalisor S felis should be considered. Study funded by Bayer Animal Health, Australia 

COMMENTARY: Urinary tract infections in cats are the exception rather than the rule, especially in young  cats. This study focused on cats that had confirmed infection with an organism that had not previously been identified as a possible pathogen in the urinary tracts of cats. S felis was isolated from clinical specimens in  cats starting in 1989 and is considered a normal commensal organism of the skin. Differentiating E faecalis  from S felis is important because E faecalis has a different susceptibility profile and requires higher dosages,  longer duration, and in some cases a combination of therapeutic agents.On the other hand, treatment of S  felis infection is relatively uncomplicated.

Prevalence of bacterial species in cats with clinical signs of lower urinary tract disease:Recognition of Staphylococcus felisas a possible feline urinary tract pathogen. Litster A,Moss SM,Honnery M,et al.VET MICROBIOL121:182-188,2007.