Gelalcha Benti D, Mohamed Ruwaa I, Gelgie Aga Edema, Kerro Dego Oudessa
Department of Animal Science, The University of Tennessee, Knoxville, TN, United States.
Department of Genome Science and Technology, The University of Tennessee, Knoxville, TN, United States.
Front Microbiol. 2024 Sep 24;15:1439363. doi: 10.3389/fmicb.2024.1439363. eCollection 2024.
The rising prevalence of Extended-Spectrum Beta-Lactamase (ESBL)-producing species (spp.) poses a significant threat to human and animal health and environmental safety. To address this pressing issue, a comprehensive study was undertaken to elucidate the burden and dissemination mechanisms of ESBL- spp. in dairy cattle farms.
Fifty-seven species were isolated on CHROMagar™ ESBL plates and confirmed with MADLI-TOF MS and whole genome sequenced from 14 dairy farms.
Six families of beta-lactamase () ( , , , , and ) were detected in ESBL- spp. genomes. Most (73%) of isolates had the first three types of beta-lactamase genes, with being the most frequent, followed by . Most (93%) isolates harbored two or more bla genes. The isolates were genotypically MDR, with 26 distinct types of antibiotic resistance genes (ARGs) and point mutations in , , and genes. The genomes also harbored 22 different plasmid replicon types, including three novel IncFII. The IncFII and Col440I plasmids were the most frequent and were associated with and genes, respectively. Eighteen distinct sequence types (STs), including eight isolates with novel STs of , were detected. The most frequently occurring STs were ST353 ( = 8), ST469 ( = 6), and the novel ST7501 ( = 6). Clusters of ESBL- strains with identical STs, plasmids, and ARGs were detected in multiple farms, suggesting possible clonal expansion. The same ESBL variant was linked to identical plasmids in different STs in some farms, suggesting horizontal spread of the resistance gene. The high burden and dual spread mechanism of ESBL genes in species, combined with the emergence of novel sequence types, could swiftly increase the prevalence of ESBL- spp., posing significant risks to human, animal, and environmental health. Immediate action is needed to implement rigorous surveillance and control measures to mitigate this risk.
产超广谱β-内酰胺酶（ESBL）细菌物种的日益流行对人类、动物健康及环境安全构成了重大威胁。为解决这一紧迫问题，开展了一项全面研究以阐明奶牛场中ESBL细菌的负担及传播机制。
在CHROMagar™ ESBL平板上分离出57个物种，并通过基质辅助激光解吸电离飞行时间质谱（MADLI-TOF MS）进行确认，然后对来自14个奶牛场的样本进行全基因组测序。
在ESBL细菌基因组中检测到6个β-内酰胺酶家族（A、C、D、G、O和T）。大多数（73%）分离株具有前三种类型的β-内酰胺酶基因，其中blaCTX-M最为常见，其次是blaTEM。大多数（93%）分离株携带两个或更多bla基因。这些分离株在基因型上具有多重耐药性，带有26种不同类型的抗生素抗性基因（ARG），且gyrA、parC和mecA基因存在点突变。基因组中还存在22种不同的质粒复制子类型，包括三种新型IncFII。IncFII和Col440I质粒最为常见，分别与blaCTX-M和blaTEM基因相关。检测到18种不同的序列类型（ST），包括8株具有新型ST的blaCTX-M分离株。最常见的ST是ST353（n = 8）、ST469（n = 6）和新型ST7501（n = 6）。在多个农场中检测到具有相同ST、质粒和ARG的ESBL菌株簇，表明可能存在克隆扩增。在一些农场中，相同的ESBL变体与不同ST中的相同质粒相关联，表明抗性基因存在水平传播。ESBL基因在细菌中的高负担和双重传播机制，再加上新型序列类型的出现，可能迅速增加产ESBL细菌的流行率，对人类、动物和环境健康构成重大风险。需要立即采取行动实施严格的监测和控制措施以降低这种风险。
