Science Digest: What is the impact of subclinical bacteriuria in cats with CKD, with or without antimicrobial treatment?

20 July 2026

Subclinical bacteriuria (SBU) is frequently encountered in cats with chronic kidney disease (CKD), but the mechanisms of this predisposition are not fully understood, and it’s not clear if it is associated with survival and disease progression. There are currently no clear guidelines for the management of SBU in cats with CKD or the associations of antimicrobial treatment on SBU in cats with CKD. #

A new study, published in the Journal of Veterinary Internal Medicine, has evaluated the association between SBU and survival time and disease progression in cats with CKD, with or without antimicrobial treatment.1

Researchers retrospectively reviewed medical records from four veterinary teaching hospitals of 287 cats that had been diagnosed with CKD, had a documented urine culture result from cystocentesis, and no signs of lower urinary tract disease. 109 cats with SBU were compared with 178 cats with a negative urine culture.

SBU in cats with CKD was not associated with reduced survival or an increased frequency of CKD progression over the following 12 months. CKD progression occurred in 42% of cats with SBU and 40% of cats in the control group. Higher plasma creatinine concentration was significantly associated with lower survival.

Female cats had a significantly higher risk of developing SBU compared to males, as found in previous studies. Lower body weight and older age were also associated with SBU, although these associations were not significant in the multivariate analysis.

Antimicrobials were prescribed to 78% of cats with SBU, 41% of which were treated before susceptibility testing. Antimicrobial treatment didn’t prevent bacterial persistence or recolonization, and similar proportions of cats progressed to cystitis or pyelonephritis with and without antimicrobial treatment. Antimicrobial treatment failed to permanently sterilize the urine of 62% of cats, as multiple SBU/UTI were detected in these cases. However, bacteriuria remained subclinical in the majority (78%) of these cases. When antimicrobial treatment was not given, bacteriuria persisted in all cases. However, the study was unable to assess the potential effects of withholding antimicrobial treatment on survival and CKD progression, due to the limited number of untreated cats. These findings don’t support routine antimicrobial treatment in SBU cats with CKD.

From the cats with SBU, Escherichia coli was the most frequently isolated species (68% of isolates), followed by Enterococcus spp. (17%). Staphylococcus spp. (5%), Pseudomonas spp. (5%), and a single occurrence of Streptococcus spp., Kluyvera spp., Klebsiella pneunomiae, Pasteurella multocida, Pantoea spp., and Proteus spp. were identified in a limited number of cats.

Limitations of the study include the relatively small sample size; incomplete follow-up; the potential for selection bias, as urine cultures were more likely to be performed in cats with CKD that showed abnormal clinical findings; differences in diagnostic and therapeutic protocols between participating hospitals; and the possibility that acute or chronic pyelonephritis and absence of LUTS could not be definitively ruled out in all cases.

Take home message

SBU is not associated with reduced survival or CKD progression in cats. Antimicrobial treatment didn’t achieve urinary sterilization in most cases, and progression to bacterial cystitis or pyelonephritis still occurred. Routine antimicrobial treatment of SBU in cats with CKD is not supported.

Reference

1 – Le Corre E, Jousserand N, Maurey C, Krafft E, Lavoué R, Drut A & Rostang A (2026) Clinical outcomes and association with disease progression and survival of subclinical bacteriuria in cats with chronic kidney disease: a multicenter retrospective study. Journal of Veterinary Internal Medicine. 40(2), https://doi.org/10.1093/jvimsj/aalag064