Antimicrobial resistance in Pasteurella and Mannheimia: epidemiology and genetic basis

Isolates of the genera Pasteurella and Mannheimia cause a wide variety of d iseases of great economic importance in poultry, pigs, cattle and rabbits. Antimicrobial agents represent the most powerful tools to control such infe ctions. However, increasing rates of antimicrobial resistance may dramatica lly reduce the efficacy of the antimicrobial agents used to control Pasteur ella and Mannheimia infections. This review presents a short summary of the infections caused by Pasteurella and Mannheimia isolates in food-producing animals and the possibilities of preventing and controlling primary and se condary pasteurellosis. Particular reference is given to antimicrobial chem otherapy and the resistance properties of Pasteurella and Mannheimia isolat es. The genetic basis of the most predominant resistance properties such as resistance to beta -lactam antibiotics, tetracyclines, aminoglycosides, su lfonamides, and chloramphenicol is discussed. This is depicted with referen ce to the role of plasmids and transposons in the spread of the resistance genes among Pasteurellaceae and members of other bacterial families and gen era.