Bacterial isolates, antimicrobial susceptibility and multidrug resistance in cultures from samples collected from beef and pre-production dairy cattle in New Zealand (2003–2016)

ABSTRACTAims: To describe the common species and the antimicrobial susceptibility of bacteria cultured from samples submitted to commercial veterinary diagnostic laboratories from beef and pre-production dairy cattle between 2003–2016, and to describe the proportion of isolates with multidrug resistance (MDR).Methods: Bacterial culture and antimicrobial susceptibility data from July 2003 to March 2016 were obtained from commercial veterinary diagnostic laboratories in New Zealand. Results were included from samples from beef cattle, irrespective of age or sex, dairy-breed females aged <2 years and dairy-breed males of any age. Submission information provided included the specimen description, the organisms cultured, and the antimicrobial susceptibilities of isolates, if tested. Antimicrobial resistance (AMR) was defined as any isolate not showing susceptibility to an antimicrobial compound and MDR as any isolate showing AMR to ≥3 antimicrobial classes.Results: There were 1,858 unique laboratory submission...