Molecular Characteristics of Klebsiella pneumoniae Isolated from Pigs Originating in Xinxiang, Henan Province.

Animal-derived Klebsiella pneumoniae can serve as a crucial reservoir for transmitting drug resistance genes and virulence factors of pathogens. Therefore, investigating the molecular characteristics of K. pneumoniae isolated from animal origin in different regions is of great significance. This study determined the minimum inhibitory concentration of 65 K. pneumoniae 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 K. pneumoniae 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 blaCTX-M gene was the highest, followed by blaSHV and blaTEM. Among the genes encoding quinolone resistance, gyrA had the highest carriage rate, followed by qnrB, qnrA, and oqxA. 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 magA, fimH-1, markD, entB, rmpA, iroNB, iucA, and iutA, 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 K. pneumoniae 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 K. pneumoniae is of great significance for preventing the transmission of this bacterium between different hosts and regions.