Alhamami Tamara, Chowdhury Piklu Roy, Gomes Nancy, Carr Mandi, Veltman Tania, Khazandi Manouchehr, Mollinger Joanne, Deutscher Ania T, Turni Conny, Mahdi Layla, Venter Henrietta, Abraham Sam, Djordjevic Steven P, Trott Darren J
Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy Campus, Roseworthy, SA 5371, Australia.
The ithree Institute, University of Technology Sydney, City Campus, Ultimo, NSW 2007, Australia.
Microorganisms. 2021 Jun 17;9(6):1322. doi: 10.3390/microorganisms9061322.
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 and 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 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 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 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 isolates, whereas isolates were more heterogeneous. Illumina whole genome sequencing identified the genes (E) and (E)encoding macrolide resistance, (R)-(H) or (Y) encoding tetracycline resistance, and 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 and from BRD cases in Australia, which should be closely monitored.
牛呼吸道疾病（BRD）在全球范围内导致肉牛的高发病率和死亡率。对BRD病原体进行抗菌药物耐药性（AMR）监测对于促进兽医学中合理的抗菌药物管理以实现最佳治疗和控制至关重要。在此，对从澳大利亚四个州（2014 - 2019年）的饲养场中BRD临床病例（死后深部肺拭子）分离得到的 和 菌株，测定了其对19种抗菌药物的敏感性。除了来自新南威尔士州（NSW）的一株对大环内酯类耐药的分离株（1/88；1.1%）外， 分离株对所有测试药物均呈泛敏感。 分离株对四环素（18/140；12.9%）、替米考星（19/140；13.6%）、图拉霉素/加米霉素（17/140；12.1%）以及氨苄西林/青霉素（6/140；4.6%）的耐药频率要高得多。五株 分离株（3.6%），均于2019年从新南威尔士州获得，表现出对大环内酯类和四环素的双重耐药性，另外两株来自2019年昆士兰州的分离株（1.4%）表现出对氨苄西林/青霉素、四环素和替米考星的多重耐药表型。随机扩增多态性DNA（RAPD）分型显示 分离株之间具有高度的遗传同质性，而 分离株则更为异质。Illumina全基因组测序在所有表现出相应耐药表型的分离株中鉴定出了编码大环内酯类耐药的基因（E）和（E）、编码四环素耐药的（R） - （H）或（Y）以及编码氨苄西林/青霉素耐药的 。例外情况是在两株昆士兰州分离株中鉴定出的对替米考星耐药、对图拉霉素/加米霉素敏感的表型，其遗传基础无法确定。这些结果证实了澳大利亚BRD病例中 和 首次出现AMR，应密切监测。
