Molecular Characteristics of <i>Klebsiella pneumoniae</i> Isolated from Pigs Originating in Xinxiang, Henan Province

Animal-derived <i>Klebsiella pneumoniae</i> can serve as a crucial reservoir for transmitting drug resistance genes and virulence factors of pathogens. Therefore, investigating the molecular characteristics of <i>K. pneumoniae</i> isolated from animal origin in different regions is of great significance. This study determined the minimum inhibitory concentration of 65 <i>K. pneumoniae</i> isolated from pigs by the microbroth dilution method. The drug-resistant genes and virulent factors of these strains were amplified by PCR. The correlation analysis was performed to analyze the relationship between virulence and drug resistance factors. The results showed that the drug resistance rates of the 65 <i>K. pneumoniae</i> strains against 12 common antibiotics ranged from 1.54% to 89.23%. The highest resistance rates were observed against ciprofloxacin and levofloxacin, followed by ampicillin and doxycycline. The resistance rates to kanamycin and amikacin were 64.62% and 58.46%, respectively, while the resistance rate to imipenem was relatively low at 9.23%. Among these strains, the carriage rate of the <i>bla_CTX-M</i> gene was the highest, followed by <i>bla_SHV</i> and <i>bla_TEM</i>. Among the genes encoding quinolone resistance, <i>gyrA</i> had the highest carriage rate, followed by <i>qnrB</i>, <i>qnrA</i>, and <i>oqxA</i>. Biofilm formation was detected in 86.15% of the strains, while 63.08% exhibited a high-mucoid phenotype. The virulence genes carried by these strains included <i>magA</i>, <i>fimH-1</i>, <i>markD</i>, <i>entB</i>, <i>rmpA</i>, <i>iroNB</i>, <i>iucA</i>, and <i>iutA</i>, with carriage rates ranging from 44.62% to 100.00%. Correlation analysis revealed a positive correlation between biofilm formation and the hypermucoviscous phenotype. The prevalent porcine <i>K. pneumoniae</i> in this region exhibit diversity in drug resistance, virulence phenotypes, virulence factors, and drug resistance genes. Strengthening the detection of molecular characteristics of porcine-derived <i>K. pneumoniae</i> is of great significance for preventing the transmission of this bacterium between different hosts and regions.