AUTHOR=Wu Zengshuai , Li Na , Li Ziheng , Wang Jianlong , Liu Mengmeng , Qi Mengzhu , Wei Shaopeng , Wu Tong , Guo Yu , Zhu Junhui , Jiang Hexiang , Xue Ruixue , Sun Changjiang , Feng Xin , Gu Jingmin , Han Wenyu , Li Fengyang , Lei Liancheng 

TITLE=Development and application of an indirect ELISA and nested PCR for the epidemiological analysis of Klebsiella pneumoniae among pigs in China

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1329609

DOI=10.3389/fmicb.2023.1329609

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p><italic>Klebsiella pneumoniae</italic> (<italic>K. pneumoniae</italic>) is an important opportunistic and zoonotic pathogen which is associated with many diseases in humans and animals. However, the pathogenicity of <italic>K. pneumoniae</italic> has been neglected and the prevalence of <italic>K. pneumoniae</italic> is poorly studied due to the lack of rapid and sensitive diagnosis techniques.</p></sec><sec><title>Methods</title><p>In this study, we infected mice and pigs with <italic>K. pneumoniae</italic> strain from a human patient. An indirect ELISA was established using the KHE protein as the coating protein for the detection of <italic>K. pneumoniae</italic> specific antibody in clinical samples. A nested PCR method to detect nuclei acids of <italic>K. pneumoniae</italic> was also developed.</p></sec><sec><title>Results</title><p>We showed that infection with <italic>K. pneumoniae</italic> strain from a human patient led to mild lung injury of pigs. For the ELISA, the optimal coating concentration of KHE protein was 10 µg/mL. The optimal dilutions of serum samples and secondary antibody were 1:100 and 1:2500, respectively. The analytical sensitivity was 1:800, with no cross-reaction between the coated antigen and porcine serum positive for antibodies against other bacteria. The intra-assay and inter-assay reproducibility coefficients of variation are less than 10%. Detection of 920 clinical porcine serum samples revealed a high <italic>K. pneumoniae</italic> infection rate by established indirect ELISA (27.28%) and nested PCR (19.13%). Moreover, correlation analysis demonstrated infection rate is positively correlated with gross population, Gross Domestic Product (GDP), and domestic tourists.</p></sec><sec><title>Discussion</title><p>In conclusion, <italic>K. pneumoniae</italic> is highly prevalent among pigs in China. Our study highlights the role of <italic>K. pneumoniae</italic> in pig health, which provides a reference for the prevention and control of diseases associated with <italic>K. pneumoniae</italic>.</p></sec>