The Utility of Acute-Phase Proteins in the Assessment of Treatment Response in Dogs With Bacterial Pneumonia

Viitanen, S.J.; Lappalainen, A.K.; Christensen, M.B.; Sankari, S.; Rajamäki, M.M.

in determining optimal treatment duration. 27, [29] [30] [31] 33, 34, 60 No published clinical studies exist addressing the optimal duration of antimicrobials in dogs with BP, and current recommendations may overestimate the treatment duration needed, especially in uncomplicated cases. Considering the variety of infectious agents and the individual differences in the interactions between microbe and the host immune system, a need also exists in dogs with BP for customizing antibiotic treatment duration according to disease severity and response rate. In our study, normalization of CRP was used to guide duration of antimicrobial treatment in 8 of 17 dogs and resulted in significantly decreased treatment duration compared to 9 of 17 conventionally treated dogs. It would have been ideal to randomize the chosen treatment regimen and stratify the randomization according to disease severity. Instead, conventional treatment was used at the beginning of the study, because previous information on the applicability of CRP to predict treatment duration was lacking. When clinical experience was gained and serum CRP was found to reflect the recovery process well, it was considered safe to stop administering antibiotics after CRP normalization. Ending antimicrobials at the point of CRP normalization was still considered premature and, to increase safety, antimicrobials were administered for 5-7 days after CRP normalization. Relapses of BP were not noted in dogs receiving a CRP-guided course of antibiotics, and therefore, the approach appears to be safe. However, because the incidence of relapse was low in both groups, our study was not able to identify an optimal end point for antimicrobial treatment and even shorter courses than those used in the CRP-guided group may have been sufficient in dogs with BP. Additionally, the small number of dogs and lack of randomization are limitations, and larger randomized studies are warranted.