Liang Jiayu, Lin Shanshan, He Lanbo
Department of Traditional Chinese Medicine, Navy 905 Hospital, Shanghai, 200052, China.
Department of Pulmonary Diseases of Traditional Chinese Medicine, Rui'an Traditional Chinese Medicine Hospital, Wenzhou 325200, China.
Cell Mol Biol (Noisy-le-grand). 2023 Oct 31;69(10):88-93. doi: 10.14715/cmb/2023.69.10.12.
This study was to explore the formation ability of biofilm and capsule and the drug resistance mechanism for multidrug-resistant Klebsiella pneumoniae. firstly, 55 strains of K. pneumoniae were screened out from the body fluid specimens of the laboratory. The strains were drug-resistant, and the characteristics of clinical infections of these strains were analyzed. Secondly, all strains were tested for the presence of biofilms and capsules, and then the deoxyribonucleic acid (DNA) genomes of the strains extracted were detected using polymerase chain reaction (PCR) technology. Finally, the serotype genes and virulence genes of the strains were screened, and the relationship between these two genes and the formation of capsules and biofilms was analyzed and compared. A new generation of sequencing technology was applied to analyze the genome structure of K. pneumoniae, comparative genomics technology was adopted to analyze the drug resistance plasmids, and molecular cloning and other methods were utilized to clone the drug resistance-related genes. of the 55 strains of K. pneumoniae isolated clinically, 61.8% came from blood with a total number of 34 strains; 8 strains were from secretion specimens (accounting for 14.5% of the total); and 7 strains were from drainage fluid (accounting for 12.7% of the total), including 2 strains from pus, bile, and pleural fluid, respectively. The strains were tested by PCR, of which iroN virulence genes were the most (34 strains), accounting for 61.8%, followed by wabG and fimH (33 strains, accounting for 60% of the total), followed by magA, K2, K20, K1, and K57. The positive rates of the two virulence genes (fimH and wabG) were higher in positive strains of biofilm. The drug susceptibility results showed that ampicillin and amoxicillin were more resistant to capsule-positive strains than the capsule-negative strains. K. pneumoniae had been able to form a complete capsule and biofilm, the formation rate of biofilm was higher than that of the capsule, and there was an increasing trend. The two serotype genes (K20 and K2) accounted for relatively high proportions, and K. pneumoniae carried relatively more virulence genes (wabG and fimH), which may be closely related to the capsule production of K. pneumoniae. In addition, resistance-related genes were also transferred horizontally in different strains of bacteria, forming a wide range of drug resistance, which brought great difficulties to clinical work.
本研究旨在探讨多重耐药肺炎克雷伯菌生物膜和荚膜的形成能力及其耐药机制。首先，从实验室体液标本中筛选出55株肺炎克雷伯菌。这些菌株具有耐药性，并对其临床感染特征进行了分析。其次，检测所有菌株是否存在生物膜和荚膜，然后使用聚合酶链反应（PCR）技术检测提取的菌株脱氧核糖核酸（DNA）基因组。最后，筛选菌株的血清型基因和毒力基因，并分析比较这两种基因与荚膜和生物膜形成之间的关系。应用新一代测序技术分析肺炎克雷伯菌的基因组结构，采用比较基因组学技术分析耐药质粒，并利用分子克隆等方法克隆耐药相关基因。临床分离的55株肺炎克雷伯菌中，61.8%来自血液，共34株；8株来自分泌物标本（占总数的14.5%）；7株来自引流液（占总数的12.7%），其中分别有2株来自脓液、胆汁和胸腔积液。通过PCR检测这些菌株，其中铁摄取调节蛋白N（iroN）毒力基因最多（34株，占61.8%），其次是wabG和菌毛蛋白H（fimH）（33株，占总数的60%），其次是magA、K2、K20、K1和K57。生物膜阳性菌株中两种毒力基因（fimH和wabG）的阳性率较高。药敏结果显示，氨苄西林和阿莫西林对荚膜阳性菌株的耐药性高于荚膜阴性菌株。肺炎克雷伯菌能够形成完整的荚膜和生物膜，生物膜的形成率高于荚膜，且呈上升趋势。两种血清型基因（K20和K2）所占比例相对较高，肺炎克雷伯菌携带的毒力基因（wabG和fimH）相对较多，这可能与肺炎克雷伯菌的荚膜产生密切相关。此外，耐药相关基因也在不同菌株间水平转移，形成广泛的耐药性，给临床工作带来极大困难。
