Measurement of Intervention Strategies for the Treatment and (Prevention?) of Mycoplasmal Pneumonia using a Model System Eileen L. Thacker, DVM, PhD, DACVM Iowa State University

Measurement of Intervention Strategies Goals and measurements:Goals and measurements: –productivity –clinical disease - coughing –percentage of pneumonia – lung lesions macroscopicmacroscopic microscopicmicroscopic –number of organisms reductionreduction sterilizationsterilization

This will determine what parameters need to be measured

What do we need to measure for antibiotics? Production parametersProduction parameters Clinical diseaseClinical disease Percentage of pneumoniaPercentage of pneumonia Number of organismsNumber of organisms

M. hyopneumoniae Isolation of the organismIsolation of the organism –Difficult –Limited number of field isolates available – virulence? Growth of the organismsGrowth of the organisms Long term effect of culture on organismLong term effect of culture on organism

First Step Determine in vitro susceptibilities and the MICDetermine in vitro susceptibilities and the MIC –field isolates Culture techniquesCulture techniques In vitro culture techniquesIn vitro culture techniques Care must be taken when interpreting in relation to results in the pigCare must be taken when interpreting in relation to results in the pig

In the Pig - Alone Pure infectionPure infection –strain 232 –others??? ModelModel –culture vs lung homogenate Production parametersProduction parameters Percentage of pneumonia – consistencyPercentage of pneumonia – consistency Number of organisms – what assays?Number of organisms – what assays?

Field Trials What mimics “the real world”What mimics “the real world” –Variation between systems –What pathogens –Identification of pathogens –Role of other pathogens What do we measure?What do we measure? Antibiotic effect on secondary pathogensAntibiotic effect on secondary pathogens

Model Field Trials Co-infections?Co-infections? –M. hyopneumoniae –P. multocida –APP –PRRSV –SIV –Circo –etc. – where do we stop?

Answers Difficult to determineDifficult to determine Best needs and interests of the industryBest needs and interests of the industry –what does M. hyopneumoniae on the label mean? Can be doneCan be done –CTC has been shown if administered prior to challenge to reduce number of organisms –unsuccessful with others

Questions - Many