Klebsiella pneumoniae isolated from dairy herds in Brazil

Klebsiella pneumoniae is one of the causative agents of clinical mastitis. Due to the increasing number of resistant K. pneumoniae treating mastitis can be challenging. Therefore, this study aimed to characterize phenotypic and genotypic patterns of antimicrobial resistance in K. pneumoniae isolated from Brazilian dairy herd farms. The phenotype was studied using the Kirby Bauer method and the double disk diffusion test. The WGS data belong to three ESBL producer samples (two mastitis isolates - ID190 and ID48 and one isolated from a bulk tank - IDTQ2). Our data shows the presence of blactxm8 and blashv108. Our samples presented a IncI1 pST114 plasmid. When aligned with a reference sequence it presented evidence of being the plasmid harbouring the bla-ctx-m8 gene. Additionally, all samples were part of ST281 and presented the same mobile elements with the exception of the tank isolate that presented an extra phage sequence P4 and one extra plasmid replicon IncX3. They also presented virulence genes previously associated with K. pneumoniae isolated from human infections such as iroE and iroN and proteins from the secretion system type I, II and IV. ESBL strains isolated from animal production containing mobile elements and human associated virulence factors represent a threat to public health, reinforcing the importance of One Health approach to monitor and control the spread of multiresistant bacteria in different niches.

肺炎克雷伯菌（Klebsiella pneumoniae）是临床乳腺炎的致病菌之一。随着耐药肺炎克雷伯菌菌株数量不断增加，乳腺炎的治疗面临较大挑战。因此，本研究旨在对从巴西奶牛场分离得到的肺炎克雷伯菌的抗菌耐药性表型与基因型特征进行解析。表型分析采用柯比-鲍尔（Kirby Bauer）法与双纸片扩散试验开展。全基因组测序（Whole Genome Sequencing, WGS）数据来自3株产超广谱β-内酰胺酶（Extended-Spectrum Beta-Lactamases, ESBL）菌株：2株分离自乳腺炎病例（ID190与ID48），1株分离自散装奶罐（IDTQ2）。本研究数据显示菌株携带blaCTX-M-8与blaSHV-108基因。受试菌株均携带IncI1型pST114质粒，经与参考序列比对后证实，该质粒确实携带有blaCTX-M-8基因。此外，所有菌株均属于序列型281（Sequence Type 281, ST281），且携带相同的移动遗传元件；仅奶罐分离株例外，其额外携带P4噬菌体序列与IncX3型质粒复制子。受试菌株还携带此前在人源肺炎克雷伯菌感染分离株中发现的毒力基因，如iroE与iroN，以及Ⅰ型、Ⅱ型和Ⅳ型分泌系统相关蛋白。从动物养殖环境中分离得到的产ESBL菌株若携带移动遗传元件及与人源感染相关的毒力因子，将对公共卫生构成威胁，这也进一步强调了采用同一健康（One Health）策略对不同生态位中多重耐药菌的传播进行监测与防控的重要性。