Zermeño-Cervantes Lina Angélica, Martínez-Díaz Sergio Francisco, Venancio-Landeros Alberto Antony, Cardona-Félix César Salvador
Instituto Politécnico Nacional-CICIMAR, Av. Instituto Politécnico Nacional S/N, Col. Playa Palo de Santa Rita, La Paz, B. C. S., CP. 23096, México.
CONACyT-Instituto Politécnico Nacional-CICIMAR, Av. Instituto Politécnico Nacional S/N, Col. Playa Palo de Santa Rita, La Paz, B. C. S., CP. 23096, México.
Res Microbiol. 2023 Sep-Oct;174(7):104104. doi: 10.1016/j.resmic.2023.104104. Epub 2023 Jul 6.
Endolysins have garnered significant attention as a potential alternative to antibiotics in aquaculture, mainly for combating Vibrio spp., Gram-negative pathogens responsible for infectious outbreaks. However, endolysin effectiveness against Gram-negative bacteria is limited due to the outer membrane's poor permeability. The combat against marine pathogens poses an additional challenge of finding endolysins that retain their activity in high ionic strength conditions. Thus, this study aimed to demonstrate that certain endolysins retain muralytic activity in seawater and also evaluated outer membrane permeabilizers as endolysin adjuvants. The effectiveness of KZ144 and LysPA26 endolysins, along with EDTA and oregano essential oil, was evaluated against Vibrio parahaemolyticus ATCC-17802 in natural seawater. Results revealed the muralytic activity of both endolysins in seawater. However, the endolysins appeared to counteract the permeabilizers' effect during the initial bactericidal assays. Further investigations revealed that the observed effect was not antagonistic. After the permeabilizer action, V. parahaemolyticus likely used endolysins as a growth substrate. Endolysins may not play an indifferent role if they fail to exert a bactericidal effect. Instead, they can serve as a substrate for fast-growing bacteria, such as V. parahaemolyticus, increasing bacterial density. It should be considered a potential drawback of endolysins' proteinaceous nature as bactericidal agents.
溶菌酶作为水产养殖中抗生素的潜在替代品已引起广泛关注，主要用于对抗弧菌属，这是一类导致感染性疫情爆发的革兰氏阴性病原体。然而，由于外膜通透性较差，溶菌酶对革兰氏阴性菌的有效性有限。对抗海洋病原体还面临着另一个挑战，即要找到在高离子强度条件下仍能保持活性的溶菌酶。因此，本研究旨在证明某些溶菌酶在海水中仍保留溶壁活性，并评估外膜通透剂作为溶菌酶佐剂的效果。在天然海水中，评估了KZ144和LysPA26溶菌酶以及乙二胺四乙酸（EDTA）和牛至精油对副溶血性弧菌ATCC - 17802的有效性。结果显示两种溶菌酶在海水中均具有溶壁活性。然而，在最初的杀菌试验中，溶菌酶似乎抵消了通透剂的作用。进一步研究表明，观察到的这种作用并非拮抗作用。在通透剂发挥作用后，副溶血性弧菌可能将溶菌酶用作生长底物。如果溶菌酶未能发挥杀菌作用，它们可能并非起无关紧要的作用。相反，它们可以作为快速生长细菌（如副溶血性弧菌）的底物，从而增加细菌密度。作为杀菌剂，溶菌酶的蛋白质性质应被视为一个潜在的缺点。
