Detection of portal and systemic bacteremia in dogs with severe induced hepatic disease and multiple portosystemic shunts

Abstract Objective To determine existence of portal and systemic bacteremia in dogs with induced severe hepatic disease, compared with clinically normal dogs, before and after vena caval banding. Animals 6 control dogs and 10 dogs with induced severe hepatic disease and multiple portosystemic shunts (PSS). Procedure Dogs of the diseased group were given dimethylnitrosamine (2 mg/kg of body weight, PO) twice weekly until multiple PSS developed. Surgery was performed on dogs of both groups, and blood for baseline aerobic and anaerobic bacterial culture was collected from catheters placed in the portal and hepatic veins and caudal vena cava. All dogs underwent vena caval banding, and blood for aerobic and anaerobic bacterial culture was collected from the portal and hepatic venous catheters at 120, 240, and 360 minutes after banding. Results Compared with control dogs (16% gram-positive and 84% gram-negative bacteria), diseased dogs had significantly higher percentage of gram-positive bacteria (42% of positive culture results, P ≤ 0.01) and significantly lower percentage of gram-negative bacteria (58% of positive culture results, P ≤ 0.01) isolated. Pseudomonas aeruginosa was isolated most frequently from dogs of both groups; more than 1 organism was isolated from 5 dogs of each group. Antimicrobial susceptibility included that to aminoglycosides (particularly amikacin), fluorinated quinolones, and imipenem. Conclusions Portal and systemic, predominantly gram-negative, bacteremia is present in catheterized, clinically normal dogs and dogs with dimethylnitrosamine-induced hepatic disease and multiple PSS. (Am J Vet Res 1999;60:181-185)