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

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/k g of body weight, PO) twice weekly until multiple PSS developed. Surgery wa s performed on dogs of both groups, and blood for baseline aerobic and anae robic bacterial culture was collected from catheters placed in the portal a nd hepatic veins and caudal vena cava. All dogs underwent vena caval bandin g, 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% grampositive and 84% gram-negative bacteria), diseased dogs had significantly higher percentage of gram-positi ve bacteria (42% of positive culture results, P less than or equal to 0.01) and significantly lower percentage of gramnegative bacteria (58% of positi ve culture results, P less than or equal to 0.01) isolated. Pseudomonas aer uginosa was isolated most frequently from dogs of both groups; more than 1 organism was isolated from 5 dogs of each group. Antimicrobial susceptibili ty included that to aminoglycosides (particularly amikacin), fluorinated qu inolones, and imipenem. Conclusions-Portal and systemic, predominantly gram-negative, bacteremia is present in catheterized, clinically normal dogs and dogs with dimethylnitr osamine-induced hepatic disease and multiple PSS.