Pertics Botond Zsombor, Kovács Tamás, Schneider György
Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Szigeti St. 12., H-7624 Pécs, Hungary.
Department of Biotechnology, Nanophagetherapy Center, Enviroinvest Corporation, Kertváros St. 2., H-7632 Pécs, Hungary.
Microorganisms. 2023 Mar 6;11(3):669. doi: 10.3390/microorganisms11030669.
is a nosocomial pathogen. Among its virulence factors is the capsule with a prominent role in defense and biofilm formation. Bacteriophages (phages) can evoke the lysis of bacterial cells. Due to the mode of action of their polysaccharide depolymerase enzymes, phages are typically specific for one bacterial strain and its capsule type. In this study, we characterized a bacteriophage against the capsule-defective mutant of the nosocomial 52145 strain, which lacks K2 capsule. The phage showed a relatively narrow host range but evoked lysis on a few strains with capsular serotypes K33, K21, and K24. Phylogenetic analysis showed that the newly isolated Klebsiella phage 731 belongs to the genus in the family; it has a 31.084 MDa double-stranded, linear DNA with a length of 50,306 base pairs and a G + C content of 50.9%. Out of the 79 open reading frames (ORFs), we performed the identification of , coding for a trimeric tail fiber protein with putative capsule depolymerase activity, along with the mapping of other putative depolymerases of phage 731 and homologous phages. Efficacy of a previously described recombinant K2 depolymerase (B1dep) was tested by co-spotting phage 731 on strains, and it was demonstrated that the B1dep-phage 731 combination allows the lysis of the wild type 52145 strain, originally resistant to the phage 731. With phage 731, we showed that B1dep is a promising candidate for use as a possible antimicrobial agent, as it renders the virulent strain defenseless against other phages. Phage 731 alone is also important due to its efficacy on strains possessing epidemiologically important serotypes.
是一种医院病原体。在其毒力因子中，荚膜在防御和生物膜形成中起重要作用。噬菌体可以引起细菌细胞的裂解。由于其多糖解聚酶的作用方式，噬菌体通常对一种细菌菌株及其荚膜类型具有特异性。在本研究中，我们对一种针对医院52145菌株的荚膜缺陷突变体的噬菌体进行了表征，该突变体缺乏K2荚膜。该噬菌体显示出相对较窄的宿主范围，但能在一些具有荚膜血清型K33、K21和K24的菌株上引起裂解。系统发育分析表明，新分离的克雷伯氏菌噬菌体731属于该科的属；它有一个31.084 MDa的双链线性DNA，长度为50306个碱基对，G + C含量为50.9%。在79个开放阅读框（ORF）中，我们鉴定了编码具有假定荚膜解聚酶活性的三聚体尾丝蛋白的基因，同时对噬菌体731和同源噬菌体的其他假定解聚酶进行了定位。通过将噬菌体731与菌株共点样，测试了先前描述的重组K2解聚酶（B1dep）的功效，结果表明B1dep - 噬菌体731组合能够裂解原本对噬菌体731耐药的野生型52145菌株。利用噬菌体731，我们表明B1dep是一种有前途的抗菌剂候选物，因为它使有毒菌株对其他噬菌体失去防御能力。单独的噬菌体731因其对具有重要流行病学血清型的菌株的功效也很重要。
