Sepsis and survival in critically ill calves: Risk factors and antimicrobial use.

Abstract

BACKGROUND: Sepsis is a life-threatening disease for which critically important antimicrobials (CIA) frequently are used. Diagnostic and therapeutic guidelines for sepsis and critically ill calves are largely lacking. OBJECTIVES: Identify factors associated with mortality in critically ill calves and describe bacteria obtained from blood cultures of critically ill calves with sepsis and their antimicrobial resistance. ANIMALS: Two-hundred thirty critically ill calves, mainly Belgian Blue beef cattle. METHODS: Retrospective cohort study. Logistic regression, survival analysis, and decision tree analysis were used to determine factors associated with mortality. RESULTS: Of the critically ill calves, 34.3% had sepsis and 61.3% died. The final survival model indicated that calves with sepsis (hazard risk [HR]: 1.6; 95% confidence interval [CI]: 1.0-2.5; P&#xa0;=&#xa0;.05), abnormal behavior (HR: 2.3; 95% CI: 1.3-4.0; P&#xa0;=&#xa0;.005), and hypothermia (HR: 0.82; 95% CI: 0.72-0.95; P&#xa0;=&#xa0;.01) had a significantly higher mortality risk. In a second survival model, hypothermia (HR: 0.87; 95% CI: 0.78-0.96; P&#xa0;=&#xa0;.004) and hypoglycemia (HR: 2.2; 95% CI: 1.5-3.3; P&#x2009;<&#x2009;.001) were risk factors for mortality. Decision tree analysis emphasized the importance of behavior, hypochloremia, hypoglycemia, hyperkalemia, and lung ultrasonography for mortality risk. Escherichia coli (30.6%) was most frequently isolated from blood cultures, of which 90.9% were multidrug resistant. Inappropriate use of antimicrobials was frequent for penicillin, amoxicillin, and sulfamethoxazole/trimethoprim, but less for CIA. CONCLUSIONS AND CLINICAL IMPORTANCE: Many critically ill calves have sepsis, which increases mortality risk. Bacteria involved are often resistant to first-intention antimicrobials but less resistant to CIA. The other identified risk factors for mortality can support therapeutic decision-making.