Successful treatment of infectious (Salmonella type III: 44) polyarthritis and osteomyelitis in a 4-week-old foal

Abstract

Summary This article describes the acute onset of infectious polyarthritis and osteomyelitis in a 4‐week‐old foal. Analysis of synovial fluid obtained from the left femoropatellar and right tarsocrural joints combined with clinical signs consisting of joint effusion and lameness yielded a diagnosis of septic arthritis. Bacterial culture of synovial fluid from the left stifle revealed Salmonella type III: 44. Rapid, sustained clinical improvement was noted following discontinuation of empirical antimicrobial therapy (potassium penicillin and amikacin sulphate) and initiation of treatment with ceftiofur and ampicillin. The importance of combining knowledge of veterinary pharmacology and microbiology so that appropriate antimicrobials may be selected with regard to the local environment in which they are to eradicate infection is emphasised. Despite frequent reference to amikacin sulphate as an effective antimicrobial for treating infections in foals caused by Salmonella, factors are discussed that explain why amikacin may not be clinically effective for treating infectious arthritis caused by Salmonella.

Orthopaedic infections; laboratory testing and response to therapy

“…While a positive culture (and accompanying antimicrobial susceptibility data) is very useful in the management of synovial sepsis and orthopaedic infections in general, it is not a guarantee for successful treatment and needs to be interpreted in light of other findings. As was the case in the report by Close et al . (2011) knowledge of a particular organism or susceptibility pattern, may change the treatment approach when there has been an unsatisfactory response to initial therapy.…”

“…1999) and anecdotal evidence of a poor prognosis when treating orthopaedic infections that involve Salmonella spp. , the report by Close et al . (2011) should serve as a reminder that microbiologists are part of the veterinary ‘team’ in such cases and their input can serve us well in making good clinical decisions.…”

“…This number is exactly as stated, a guide. Synovial fluid cytology can also be used to monitor response to therapy, as stated in the report by Close et al . (2011) where a reduction in synovial WBC count and protein levels may indicate resolution of sepsis.…”

“…The initial treatments employed in the management of the foal in the case report by Close et al . (2011) including the empirical antimicrobial treatment with amikacin and penicillin, would be considered appropriate by most standards.…”

“…The Case Report in this issue on successful treatment of polyarthritis and osteomyelitis caused by Salmonella spp. in a foal (Close et al . 2011) is not a particularly unique case, nor a complicated variation on the typical case of neonatal septic synovitis/osteomyelitis.…”