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Observations on macrolide resistance and susceptibility testing performance in field isolates collected from clinical bovine respiratory disease cases
- Source :
- Veterinary microbiology. 192
- Publication Year :
- 2016
-
Abstract
- The objectives of this study were; first, to describe gamithromycin susceptibility of Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni isolated from cattle diagnosed with bovine respiratory disease (BRD) and previously treated with either gamithromycin for control of BRD (mass medication=MM) or sham-saline injected (control=CON); second, to describe the macrolide resistance genes present in genetically typed M. haemolytica isolates; third, use whole-genome sequencing (WGS) to correlate the phenotypic resistance and genetic determinants for resistance among M. haemolytica isolates. M. haemolytica (n=276), P. multocida (n=253), and H. somni (n=78) were isolated from feedlot cattle diagnosed with BRD. Gamithromycin susceptibility was determined by broth microdilution. Whole-genome sequencing was utilized to determine the presence/absence of macrolide resistance genes and to genetically type M. haemolytica. Generalized linear mixed models were built for analysis. There was not a significant difference between MM and CON groups in regards to the likelihood of culturing a resistant isolate of M. haemolytica or P. multocida. The likelihood of culturing a resistant isolate of M. haemolytica differed significantly by state of origin in this study. A single M. haemolytica genetic subtype was associated with an over whelming majority of the observed resistance. H. somni isolation counts were low and statistical models would not converge. Phenotypic resistance was predicted with high sensitivity and specificity by WGS. Additional studies to elucidate the relationships between phenotypic expression of resistance/genetic determinants for resistance and clinical response to antimicrobials are necessary to inform judicious use of antimicrobials in the context of relieving animal disease and suffering.
- Subjects :
- 0301 basic medicine
animal diseases
030106 microbiology
Bovine respiratory disease
Bovine Respiratory Disease Complex
Context (language use)
Microbial Sensitivity Tests
Microbiology
03 medical and health sciences
Antibiotic resistance
Drug Resistance, Bacterial
medicine
Animals
Pasteurella multocida
Gene
General Veterinary
biology
Bacteria
Broth microdilution
General Medicine
respiratory system
biology.organism_classification
medicine.disease
Virology
Anti-Bacterial Agents
030104 developmental biology
Cattle
Macrolides
Subjects
Details
- ISSN :
- 18732542
- Volume :
- 192
- Database :
- OpenAIRE
- Journal :
- Veterinary microbiology
- Accession number :
- edsair.doi.dedup.....51a149d621dd6f84969a1ea7a3ae17e8