Monsibais Alisha N, Tea Olivia, Ghatbale Pooja, Phan Jennifer, Lam Karen, Paulson McKenna, Tran Natalie, Suder Diana S, Blanc Alisha N, Samillano Cyril, Suh Joy, Dunham Sage, Gonen Shane, Pride David, Whiteson Katrine
Dept of Molecular Biology and Biochemistry, University of California, Irvine.
Department of Pathology, University of California, San Diego.
bioRxiv. 2024 Aug 16:2024.08.14.607921. doi: 10.1101/2024.08.14.607921.
In our era of rising antibiotic resistance, (STM) is an understudied, gram-negative, aerobic bacterium widespread in the environment and increasingly causing opportunistic infections. Treating STM infections remains difficult, leading to an increase in disease severity and higher hospitalization rates in people with Cystic Fibrosis (pwCF), cancer, and other immunocompromised health conditions. The lack of effective antibiotics has led to renewed interest in phage therapy; however, there is a need for well-characterized phages. In response to an oncology patient with a respiratory infection, we collected 18 phages from Southern California wastewater influent that exhibit different plaque morphology against STM host strain B28B, cultivated from a blood sample. Here, we characterize the genomes and life cycle kinetics of our STM phage collection. We hypothesize that genetically distinct phages give rise to unique lytic life cycles that can enhance bacterial killing when combined into a phage cocktail compared to the individual phages alone. We identified three genetically distinct clusters of phages, and a representative from each group was screened for potential therapeutic use and investigated for infection kinetics. The results demonstrated that the three-phage cocktail significantly suppressed bacterial growth compared to individual phages when observed for 48 hours. We also assessed the lytic impacts of our three-phage cocktail against a collection of 46 STM strains to determine if a multi-phage cocktail can expand the host range of individual phages. Our phages remained strain-specific and infect >50% of tested strains. The multi-phage cocktail maintains bacterial growth suppression and prevents the emergence of phage-resistant strains throughout our 40-hour assay. These findings suggest specialized phage cocktails may be an effective avenue of treatment for recalcitrant STM infections resistant to current antibiotics.
在我们这个抗生素耐药性不断上升的时代，嗜麦芽窄食单胞菌（STM）是一种研究较少的革兰氏阴性需氧细菌，广泛存在于环境中，越来越多地引起机会性感染。治疗STM感染仍然很困难，导致囊性纤维化患者（pwCF）、癌症患者和其他免疫功能低下的健康状况患者的疾病严重程度增加和住院率升高。缺乏有效的抗生素引发了人们对噬菌体疗法的新兴趣；然而，需要特性明确的噬菌体。针对一名患有呼吸道感染的肿瘤患者，我们从南加州废水流入物中收集了18种噬菌体，这些噬菌体对从一份血样中培养出的STM宿主菌株B28B表现出不同的噬菌斑形态。在此，我们对我们收集的STM噬菌体的基因组和生命周期动力学进行了表征。我们假设，与单独的噬菌体相比，基因不同的噬菌体产生独特的裂解生命周期，当组合成噬菌体鸡尾酒时可以增强细菌杀伤作用。我们鉴定出了三个基因不同的噬菌体簇，并对每组中的一个代表进行了潜在治疗用途筛选和感染动力学研究。结果表明，在观察48小时时，三噬菌体鸡尾酒与单个噬菌体相比显著抑制了细菌生长。我们还评估了我们的三噬菌体鸡尾酒对46株STM菌株的裂解影响，以确定多噬菌体鸡尾酒是否可以扩大单个噬菌体的宿主范围。我们的噬菌体仍然具有菌株特异性，可感染超过50%的测试菌株。在我们40小时的试验中，多噬菌体鸡尾酒保持了对细菌生长的抑制，并防止了噬菌体抗性菌株的出现。这些发现表明，专门的噬菌体鸡尾酒可能是治疗对当前抗生素耐药的顽固性STM感染的有效途径。
