肺炎克雷伯菌是获得性感染相关的条件致病菌，被WHO列为急需研发新抗生素的耐药致病菌。铁载体因子是肺炎克雷伯菌在宿主细胞内增殖的重要毒力因子，主要包括肠杆菌素、耶尔森菌素、气杆菌素和沙门菌素。笔者前期从病猪的肝脏分离到一株多重耐药ST37型（ST）肺炎克雷伯菌KP200，文中利用生物信息学软件，分析KP200与来自NCBI的ST37型的160株肺炎克雷伯菌菌株铁载体因子的进化关系及遗传多样性。单拷贝核心基因组进化树分析表明，KP200与1株中国的人源肺炎克雷伯菌位于同一个进化支，相似度为99.8%；铁载体因子分析表明，所有161株ST37型肺炎克雷伯菌都携带肠杆菌素entABCEF和fepABC，KP200与其他15株肺炎克雷伯菌携带气杆菌素转运基因iutA，且这些iutA基因序列间核苷酸相似性为73.49%～100%。与高毒力肺炎克雷伯菌NTUH-K2044携带的iutA核苷酸序列比较，发现KP200携带的iutA核苷酸序列中两个碱基突变，导致两个氨基酸替换：即亮氨酸替换成苯丙氨酸、缬氨酸替换成亮氨酸。本研究为肺炎克雷伯菌ST37型别菌株的进化及其毒力分析提供了基础数据。

Klebsiella pneumoniae is a opportunistic pathogen associated with acquired infections and is listed by the World Health Organization （WHO） as a drug-resistant pathogen that urgently needs to develop new antibiotics.Siderophores is an important virulence factor for K.pneumoniae to proliferate in host cells，mainly including enterobactin，yersiniabactin，aerobactin，and salmochelin.A multi-drug resistant K.pneumoniae ST37 KP200 was isolated from the liver of sick pigs.This study analyzed the evolutionary relationship and genetic diversity of si-derophores of KP200 and 160 K.pneumoniae ST37 strains from NCBI with bioinformatics software.The single-copy core genes analysis results show that KP200 and a Chinese K.pneumoniae of human origin locate in the same clade with similarity of 99.8%.Siderophores analysis shows that all ST37 strains carry enterobactin entABCEF and fepABC.KP200 and other 15 K.pneumoniae strains carry aerobactin transporter gene iutA.The nucleotide homo-logy of 16 iutA gene sequences is 73.49%～100%.Compared with the iutA nucleotide sequence carried by the hypervirulent K.pneumoniae NTUH-K2044，it finds that the iutA nucleotide carried by KP200 results in two amino acid substitutions due to two base mutations： Leu is replaced by Phe and Val is replaced by Leu.This study provides basis for studying the evolution and virulence of K.pneumoniae ST37.