University of Alberta, Dept. of Agricultural, Food and Nutritional Scienence, Edmonton, AB T6G 2P5, Canada.
Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, NE 68588-6205, United States.
Lett Appl Microbiol. 2024 Feb 1;77(2). doi: 10.1093/lambio/ovae007.
The ecological relationships among antimicrobial producing, resistant, and sensitive strains have been proposed to follow rock-paper-scissors dynamics, but evidence is mainly based on Gram-negative bacteriocins in vitro. The ecological relevance of antimicrobials in vivo or in situ has not been systematically studied. This study therefore aimed to analyze binary and ternary competitions among reutericyclin-producing strain Limosilactobacillus reuteri TMW1.656, its reutericyclin-resistant, nonproducing isogenic derivative L. reuteri TMW1.656∆rtcN, and the reutericyclin-sensitive, nonproducing L. reuteri TMW1.656∆rtcN∆rtcT in vitro (liquid culture and static plate), in situ (sourdough fermentation), and in vivo (gut of germ-free mice). In liquid culture, L. reuteri TMW1.656 had a higher fitness than TMW1.656∆rtcN and TMW1.656∆rtcN∆rtcT. Limosilactobacillus reuteri TMW1.656∆rtcN∆rtcT had a higher fitness than TMW1.656∆rtcN. On agar plates, L. reuteri TMW1.656 had a higher fitness than TMW1.656∆rtcN∆rtcT. In situ, reutericyclin production and resistance had no influence on the fitness of the strains. In vivo, TMW1.656 had an advantage over TMW1.656∆rtcN and TMW1.656∆rtcN∆rtcT. Ternary competitions showed reutericyclin production was ecologically beneficial in all ecosystems. The findings support the ecological importance of reutericyclin in a variety of environments/niches, providing an explanation for the acquisition of the reutericyclin gene cluster in L. reuteri and its contribution to the ecological fitness of Streptococcus mutans.
抗微生物产生、抗性和敏感菌株之间的生态关系被提出遵循石头剪刀布动态，但证据主要基于革兰氏阴性细菌素的体外研究。抗微生物在体内或原位的生态相关性尚未得到系统研究。因此，本研究旨在分析产雷替曲塞林的罗伊氏乳杆菌 TMW1.656 菌株及其雷替曲塞林抗性、非产同种衍生株 L. reuteri TMW1.656∆rtcN 以及雷替曲塞林敏感、非产的 L. reuteri TMW1.656∆rtcN∆rtcT 在体外（液体培养和静态平板）、原位（酸面团发酵）和体内（无菌小鼠肠道）的二元和三元竞争。在液体培养中，L. reuteri TMW1.656 的适应性强于 TMW1.656∆rtcN 和 TMW1.656∆rtcN∆rtcT。Limosilactobacillus reuteri TMW1.656∆rtcN∆rtcT 的适应性强于 TMW1.656∆rtcN。在琼脂平板上，L. reuteri TMW1.656 的适应性强于 TMW1.656∆rtcN∆rtcT。在原位，雷替曲塞林的产生和抗性对菌株的适应性没有影响。在体内，TMW1.656 比 TMW1.656∆rtcN 和 TMW1.656∆rtcN∆rtcT 更具优势。三元竞争表明雷替曲塞林的产生在所有生态系统中都具有生态效益。这些发现支持了雷替曲塞林在多种环境/小生境中的重要生态作用，为罗伊氏乳杆菌中雷替曲塞林基因簇的获得及其对变异链球菌生态适应性的贡献提供了一种解释。
