Details

Autor(en) / Beteiligte

• Carter, Hannah F
• Wills, Robert W
• Scott, Matthew A
• Thompson, Alexis C
• Singer, Randall S
• Loy, John Dustin
• Karisch, Brandi B
• Epperson, William B
• Woolums, Amelia R

Titel

Assessment of Diversity of Antimicrobial Resistance Phenotypes and Genotypes of Mannheimia haemolytica Isolates From Bovine Nasopharyngeal Swabs

Ist Teil von

• Frontiers in veterinary science, 2022-05, Vol.9, p.883389-883389

Ort / Verlag

Switzerland: Frontiers Media S.A

Erscheinungsjahr

2022

Link zum Volltext

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• The threat of bovine respiratory disease (BRD) for cattle operations is exacerbated by increasing prevalence of antimicrobial resistance (AMR) in , a leading cause of BRD. Characterization of AMR in by culture and susceptibility testing is complicated by uncertainty regarding the number of colonies that must be selected to accurately characterize AMR phenotypes (antibiograms) and genotypes in a culture. The study objective was to assess phenotypic and genotypic diversity of isolates on nasopharyngeal swabs (NPS) from 28 cattle at risk for BRD or with BRD. NPS were swabbed onto five consecutive blood agar plates; after incubation up to 20 colonies were selected per plate (up to 100 colonies per NPS). Phenotype was determined by measuring minimum inhibitory concentrations (MIC) for 11 antimicrobials and classifying isolates as resistant or not. Genotype was indirectly determined by matrix-assisted laser desorption/ionization time of flight mass spectroscopy (MALDI-TOF MS). NPS from 11 of 28 cattle yielded at least one isolate; median (range) of isolates per NPS was 48 (1-94). NPS from seven cattle yielded one phenotype, 3 NPS yielded two, and 1 NPS yielded three; however, within a sample all phenotypic differences were due to only one MIC dilution. On each NPS all isolated were the same genotype; genotype 1 was isolated from three NPS and genotype two was isolated from eight. Diversity of on bovine NPS was limited, suggesting that selection of few colonies might adequately identify relevant phenotypes and genotypes.