O'Connor Paula M, Cotter Paul D, Hill Colin, Ross R Paul
Teagasc Food Research Centre, Moorepark, Co. Cork, P61 C996 Fermoy, Ireland.
APC Microbiome Ireland, University College Cork, T12 YT20 Cork, Ireland.
Antibiotics (Basel). 2025 Feb 11;14(2):184. doi: 10.3390/antibiotics14020184.
Bacteriocins can be considered a novel source of natural alternatives to antibiotics or chemical food additives with the potential to fight against clinical and food pathogens. A number have already been commercialised as food preservatives, but they also have the potential to treat drug-resistant clinical pathogens and can play a role in immune modulation. To achieve their full potential, an understanding of their mode of action is required. Bactofencin A and nisin A were purified to homogeneity by reversed-phase HPLC and their effect on the mastitis pathogen DPC5246 was assessed by cell viability assays and flow cytometry. We report that bactofencin A displays a delayed inhibitory effect against the mastitis pathogen, DPC5246, suggesting an unusual mode of action. This characteristic was clearly visible on BHI plate media, where formation of inhibition zones against the staphylococcal strain took 23 h compared to 6 h for the well-characterised nisin. This delayed killing and injury was also demonstrated using flow cytometry, where damage was evident 4 h after bacteriocin addition. Treatment with 2 μM bactofencin A resulted in approximately 20-fold higher numbers of injured and 50-fold higher numbers of dead cells when compared to untreated cells. Combining bactofencin A with the lantibiotic nisin A resulted in faster killing at lower bacteriocin concentrations. When combined in an equal ratio, the combination exhibited a 4-fold increase in inhibition compared to nisin A alone. These results demonstrate that the combination may be very effective in therapeutic applications against pathogenic staphylococci.
细菌素可被视为抗生素或化学食品添加剂的新型天然替代品来源，有潜力对抗临床和食品病原体。已有多种细菌素作为食品防腐剂实现了商业化，但它们也有治疗耐药临床病原体的潜力，并且可在免疫调节中发挥作用。为充分发挥其潜力，需要了解它们的作用模式。通过反相高效液相色谱法将杆菌防御素A和乳链菌肽A纯化至同质，并通过细胞活力测定和流式细胞术评估它们对乳腺炎病原体DPC5246的作用。我们报告称，杆菌防御素A对乳腺炎病原体DPC5246显示出延迟抑制作用，这表明其作用模式不同寻常。在BHI平板培养基上这一特性清晰可见，与特征明确的乳链菌肽相比，针对葡萄球菌菌株形成抑菌圈需要23小时，而乳链菌肽只需6小时。使用流式细胞术也证明了这种延迟杀伤和损伤，在添加细菌素4小时后损伤明显。与未处理的细胞相比，用2μM杆菌防御素A处理导致受损细胞数量增加约20倍，死亡细胞数量增加50倍。将杆菌防御素A与羊毛硫抗生素乳链菌肽A联合使用，在较低细菌素浓度下可实现更快杀伤。以等比例联合使用时，与单独使用乳链菌肽A相比，联合使用的抑菌效果提高了4倍。这些结果表明，这种联合在针对致病性葡萄球菌的治疗应用中可能非常有效。
