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First Emergence of Resistance to Macrolides and Tetracycline Identified in Mannheimia haemolytica and Pasteurella multocida Isolates from Beef Feedlots in Australia

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Alhamami, T., Chowdhury, P. R., Gomes, N., Carr, M., Veltman, T., Khazandi, M., Mollinger, J. L., Deutscher, A. T., Turni, C., Mahdi, L., Venter, H., Abraham, S., Djordjevic, S. P. and Trott, D. J. (2021) First Emergence of Resistance to Macrolides and Tetracycline Identified in Mannheimia haemolytica and Pasteurella multocida Isolates from Beef Feedlots in Australia. Microorganisms, 9 (6). p. 1322. ISSN 2076-2607

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Article Link: https://doi.org/10.3390/microorganisms9061322

Publisher URL: https://www.mdpi.com/2076-2607/9/6/1322


Bovine respiratory disease (BRD) causes high morbidity and mortality in beef cattle worldwide. Antimicrobial resistance (AMR) monitoring of BRD pathogens is critical to promote appropriate antimicrobial stewardship in veterinary medicine for optimal treatment and control. Here, the susceptibility of Mannheimia haemolytica and Pasteurella multicoda isolates obtained from BRD clinical cases (deep lung swabs at post-mortem) among feedlots in four Australian states (2014–2019) was determined for 19 antimicrobial agents. The M. haemolytica isolates were pan-susceptible to all tested agents apart from a single macrolide-resistant isolate (1/88; 1.1%) from New South Wales (NSW). Much higher frequencies of P. multocida isolates were resistant to tetracycline (18/140; 12.9%), tilmicosin (19/140; 13.6%), tulathromycin/gamithromycin (17/140; 12.1%), and ampicillin/penicillin (6/140; 4.6%). Five P. multocida isolates (3.6%), all obtained from NSW in 2019, exhibited dual resistance to macrolides and tetracycline, and a further two Queensland isolates from 2019 (1.4%) exhibited a multidrug-resistant phenotype to ampicillin/penicillin, tetracycline, and tilmicosin. Random-amplified polymorphic DNA (RAPD) typing identified a high degree of genetic homogeneity among the M. haemolytica isolates, whereas P. multocida isolates were more heterogeneous. Illumina whole genome sequencing identified the genes msr(E) and mph(E)encoding macrolide resistance, tet(R)-tet(H) or tet(Y) encoding tetracycline resistance, and blaROB-1 encoding ampicillin/penicillin resistance in all isolates exhibiting a corresponding resistant phenotype. The exception was the tilmicosin-resistant, tulathromycin/gamithromycin-susceptible phenotype identified in two Queensland isolates, the genetic basis of which could not be determined. These results confirm the first emergence of AMR in M. haemolytica and P. multocida from BRD cases in Australia, which should be closely monitored.

Item Type:Article
Business groups:Biosecurity Queensland
Additional Information:Correction of this article at https://era.daf.qld.gov.au/eprint/8718
Keywords:bovine respiratory disease; antimicrobial susceptibility; Mannheimia haemolytica; Pasteurella multocida
Subjects:Animal culture > Cattle
Veterinary medicine > Veterinary microbiology
Veterinary medicine > Veterinary parasitology
Animal culture > Housing and environmental control
Animal culture > Feeds and feeding. Animal nutrition
Live Archive:01 Jul 2021 02:13
Last Modified:05 May 2022 03:05

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