3rd generation cephalosporins are more active against Gram-negative bacteria than the 1st and 2nd generations which are rendered ineffective by production of β-lactamase. CPZ and CAZ are useful in infections caused by Pseudomonas Eft is active against Pasteurella multocida, Mannheimia haemolytica, Histophilus somnus, Fusobacterium necrophorum, Actinobacillus, Salmonella cholerasuis, Streptococcus suis. Here, CPZ is linked to infection.