Salmonella enterica subspecies houtenae as an opportunistic pathogen in a case of meningoencephalomyelitis and bacteriuria in a dog.

Background: We report the first case of canine Salmonella meningoencephalomyelitis and second case of canine Salmonella bacteriuria, as well as the first reported case of Salmonella enterica subspecies houtenae in a dog.

Case Presentation: Immunosuppressive treatment in a dog for a relapse of steroid-responsive meningitis and arteritis (SRMA) allowed for the opportunistic establishment of a bacteremia with Salmonella enterica subsp. houtenae, ultimately causing meningoencephalomyelitis and subclinical bacteriuria. The bacterial infections were treated with a four-month course of amoxicillin; clinical treatment success was determined by serial negative urine cultures and lack of clinical signs correlated to the meningoencephalomyelitis.

Conclusions: Both the bacteriuria and meningoencephalomyelitis represented opportunistic infections in a dog immunosuppressed for SRMA. The clinical course of this infectious meningoencephalitis emphasizes the importance of differentiating relapse of initial disease from opportunistic infection occurring in a compromised central nervous system. The novel Salmonella species identified in this case acts as a reminder that infectious disease diagnostics should not be curbed by anecdotal prediction of routine pathogenic suspects.