Wan Sheng-Hui, Li Nana, Zheng Pei, Li Yanfang, Liang Yan, Qu Yonggang
College of Animal Science and Technology, Shihezi University, Shihezi, 832003, China.
Xinjiang Tecon Animal Husbandry Technology Co., Ltd., Changji, 831399, China.
Porcine Health Manag. 2025 May 7;11(1):25. doi: 10.1186/s40813-025-00424-x.
This study aimed to analyze the antimicrobial resistance and pathogenicity of Klebsiella pneumoniae(K. pneumoniae) isolates from pigs, evaluate their potential threat to pig farming and public health, and provide a theoretical basis for controlling K. pneumoniae infections in pig farms.
Nasal swabs collected from pigs were subjected to bacterial isolation, biochemical identification, species-specific PCR, and 16S rRNA sequencing to identify K. pneumoniae. Serotyping and multilocus sequence typing (MLST) were conducted using the wzi and MLST methods, respectively. Biofilm formation was assessed using crystal violet staining. Antimicrobial susceptibility was evaluated via the Kirby-Bauer disk diffusion method, and resistance and virulence genes were identified using PCR. Pathogenicity was determined through string testing and mouse infection models.
21 strains of K. pneumoniae were isolated and identified from 50 swabs of pig nasal cavities. The isolates were classified into serotypes wzi 19 and wzi 81 and sequence types ST37 and ST967. Ten isolates exhibited strong biofilm-forming ability, while 11 showed moderate biofilm production. Antimicrobial susceptibility testing revealed resistance to β-lactams, aminoglycosides, quinolones, tetracyclines, sulfonamides, aminoalcohols, and glycopeptides, with sensitivity restricted to imipenem and polymyxins. Ten resistance genes and eight virulence genes were detected. Pathogenicity testing in mice revealed a moderate virulence level, with a median lethal dose (LD) of 4.0 × 10⁶ CFU/mL. Infected mice exhibited significant lesions in the liver, lungs, and small intestine.
These findings highlight a potential risk to pig farming and public health, emphasizing the need for effective control measures against K. pneumoniae infections in pig farms.
本研究旨在分析从猪身上分离出的肺炎克雷伯菌（K. pneumoniae）的耐药性和致病性，评估其对养猪业和公共卫生的潜在威胁，并为控制猪场肺炎克雷伯菌感染提供理论依据。
对从猪身上采集的鼻拭子进行细菌分离、生化鉴定、种特异性PCR和16S rRNA测序，以鉴定肺炎克雷伯菌。分别使用wzi和多位点序列分型（MLST）方法进行血清型鉴定和多位点序列分型。使用结晶紫染色评估生物膜形成。通过 Kirby-Bauer 纸片扩散法评估抗菌药物敏感性，并使用PCR鉴定耐药基因和毒力基因。通过串珠试验和小鼠感染模型确定致病性。
从50份猪鼻腔拭子中分离并鉴定出21株肺炎克雷伯菌。分离株分为血清型wzi 19和wzi 81以及序列型ST37和ST967。10株分离株表现出较强的生物膜形成能力，而11株表现出中等程度的生物膜产生。抗菌药物敏感性测试显示对β-内酰胺类、氨基糖苷类、喹诺酮类、四环素类、磺胺类、氨基醇类和糖肽类耐药，仅对亚胺培南和多粘菌素敏感。检测到10个耐药基因和8个毒力基因。小鼠致病性测试显示毒力水平中等，半数致死剂量（LD）为4.0×10⁶ CFU/mL。感染小鼠的肝脏、肺和小肠出现明显病变。
这些发现凸显了对养猪业和公共卫生的潜在风险，强调需要采取有效措施控制猪场肺炎克雷伯菌感染。
