Elbakush Ahmed M, Fulano Alex M, Gomelsky Mark
Department of Molecular Biology, University of Wyoming, Laramie, WY, United States.
Faculty of Veterinary Medicine, University of Tripoli, Tripoli, Libya.
Front Microbiol. 2023 Oct 19;14:1258394. doi: 10.3389/fmicb.2023.1258394. eCollection 2023.
Major listeriosis outbreaks have been associated with fresh produce contaminated with . Strains that synthesize the Pss exopolysaccharide (EPS) have an estimated 10 to 10-fold advantage over nonsynthesizing strains in causing listeriosis. They more readily attach to the surfaces of fruit and vegetables forming EPS-biofilms that better withstand stresses associated with produce storage and consumption. Here, we show that the threat to fresh produce safety posed by the listerial EPS-biofilms may be countered by broadly available maple products. We serendipitously discovered that aqueous extracts of wood from several (maple) and (pecan, hickory) species inhibit the formation of listerial EPS-biofilms without affecting bacterial viability. One active ingredient in maple wood was identified as nortrachelogenin-8'-O-β-D-glucopyranoside (NTG). At 120 μM, this lignan decreased colonization of the EPS-synthesizing on cantaloupe pieces by approximately 150-fold, and on cut celery and lettuce by 10 to 11-fold. Another lignan, lariciresinol, which is abundant in a common food sweetener, maple syrup, had antibiofilm activity comparable to that of NTG. Diluted in the range of 1:200 to 1:800 maple syrup from two random manufacturers prevented formation of listeiral EPS-biofilms. Importantly, not only did maple products drastically decrease colonization of fresh produce by the EPS-synthesizing strains, they also decreased, by 6 to 30-fold, colonization by the strains that do not synthesize measurable EPS, including strains from the infamous 2011 cantaloupe listeriosis outbreak. Inhibition of surface colonization by various listerial strains, broad availability of maple sap and syrup as well as maple lumber processing waste position maple products as potential antibiofilm agents for protecting fresh produce from .
主要的李斯特菌病暴发与受污染的新鲜农产品有关。合成Pss胞外多糖（EPS）的菌株在引发李斯特菌病方面比不合成的菌株具有约10到100倍的优势。它们更容易附着在水果和蔬菜表面形成EPS生物膜，这种生物膜能更好地抵御与农产品储存和消费相关的压力。在此，我们表明，广泛可得的枫糖产品可能会对抗李斯特菌EPS生物膜对新鲜农产品安全构成的威胁。我们意外发现，几种槭树（枫树）以及山核桃、胡桃木的木材水提取物可抑制李斯特菌EPS生物膜的形成，且不影响细菌活力。枫木中的一种活性成分被鉴定为降紫杉叶素 - 8'-O-β-D-吡喃葡萄糖苷（NTG）。在120μM浓度下，这种木脂素使合成EPS的菌株在哈密瓜片上的定殖减少约150倍，在切好的芹菜和生菜上减少10到11倍。另一种木脂素落叶松脂醇在一种常见的食品甜味剂枫糖浆中含量丰富，其具有与NTG相当的抗生物膜活性。来自两家随机选取制造商且稀释比例在1:200至1:800范围内的枫糖浆可阻止李斯特菌EPS生物膜的形成。重要的是，枫糖产品不仅大幅减少了合成EPS菌株在新鲜农产品上的定殖，还使不合成可测量EPS的菌株（包括臭名昭著的2011年哈密瓜李斯特菌病暴发中的菌株）的定殖减少了6到30倍。各种李斯特菌菌株表面定殖的抑制、枫糖浆和枫木加工废料的广泛可得，使枫糖产品成为保护新鲜农产品免受李斯特菌侵害的潜在抗生物膜剂。
