Acinetobacter baumannii is a nosocomial pathogen, which is a problem worldwide due to the emergence of a difficult-to-treat multidrug-resistant A. baumannii (MDRAB). Endolysins are hydrolytic enzymes produced by a bacteriophage that can be used as a potential therapeutic agent for multidrug-resistant bacterial infection in replacing antibiotics. Here, we isolated a novel bacteriophage through prophage induction using mitomycin C from clinical A. baumannii 1656-2. Morphologically, ΦAb1656-2 was identified as a Siphoviridae family bacteriophage, which can infect MDRAB. The whole genome of ΦAb1656-2 was sequenced, and it showed that it is 50.9 kb with a G + C content of 38.6% and 68 putative open reading frames (ORFs). A novel endolysin named AbEndolysin with an N-acetylmuramidase-containing catalytic domain was identified, expressed, and purified from ΦAb1656-2. Recombinant AbEndolysin showed significant antibacterial activity against MDRAB clinical strains without any outer membrane permeabilizer. These results suggest that AbEndolysin could represent a potential antimicrobial agent for treating MDRAB clinical isolates.

中文翻译：

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一种新型噬菌体 ΦAb1656-2 及其对多药耐药鲍曼不动杆菌具有较高抗菌活性的内溶素的表征

鲍曼不动杆菌是一种院内病原体，由于出现了一种难以治疗的耐多药鲍曼不动杆菌(MDRAB)，因此在世界范围内都存在问题。内溶素是由噬菌体产生的水解酶，可用作耐多药细菌感染的潜在治疗剂，以替代抗生素。在这里，我们使用来自临床鲍曼不动杆菌1656-2的丝裂霉素 C 通过前噬菌体诱导分离出一种新型噬菌体。形态学上，ΦAb1656-2被鉴定为可感染MDRAB的Siphoviridae家族噬菌体。对ΦAb1656-2的全基因组进行测序，结果显示它长50.9 kb，G+C含量为38.6%，有68个推定的开放阅读框（ORFs）。一种名为 AbEndolysin 的新型内溶素从 ΦAb1656-2 中鉴定、表达和纯化含有 N-乙酰胞壁苷酶的催化结构域。重组 AbEndolysin 对 MDRAB 临床菌株显示出显着的抗菌活性，而没有任何外膜透化剂。这些结果表明，AbEndolysin 可能代表治疗 MDRAB 临床分离株的潜在抗菌剂。