Department of Molecular Biology and Genetic Engineering, School of Bioengineering and Biosciences, Lovely Professional University, Jalandhar-Delhi G.T. Road, Phagwara, Punjab, 144401, India.
Department of Biological Sciences, Faculty of Science, Federal University of Kashere, P.M.B. 0182, Gombe, Nigeria.
Mol Biol Rep. 2024 Mar 14;51(1):419. doi: 10.1007/s11033-024-09362-3.
A novel lytic bacteriophage (phage) was isolated with Pseudomonas mendocina strain STP12 (P. mendocina) from the untreated site of Sewage Treatment Plant of Lovely Professional University, India. P. mendocina is a Gram-negative, rod-shaped, aerobic bacterium belonging to the family Pseudomonadaceae and has been reported in fifteen (15) cases of economically important diseases worldwide.
Here, a novel phage specifically infecting and killing P. mendocina strain STP12 was isolated from sewage sample using enrichment, spot test and double agar overlay (DAOL) method and was designated as vB_PmeS_STP12. The phage vB-PmeS-STP12 was viable at wide range of pH and temperature ranging from 4 to10 and - 20 to 70 °C respectively. Host range and efficiency of plating (EOP) analysis indicated that phage vB-PmeS-STP12 was capable of infecting and killing P. mendocina strain STP6 with EOP of 0.34. Phage vB_PmeS_STP12 was found to have a significant bacterial reduction (p < 0.005) at all the doses administered, particularly at optimal MOI of 1 PFU/CFU, compared to the control. Morphological analysis using high resolution transmission electron microscopy (HR-TEM) revealed an icosahedral capsid of ~ 55 nm in diameter on average with a short, non-contractile tail. The genome of vB_PmeS_STP12 is a linear, dsDNA containing 36,212 bp in size with a GC content of 58.87% harbouring 46 open reading frames (ORFs). The 46 predicted ORFs encode proteins with functional information categorized as lysis, replication, packaging, regulation, assembly, infection, immune, and hypothetical. However, the genome of vB_PmeS_STP12 appeared to be devoid of tRNAs, integrase gene, toxins genes, virulence factors, antimicrobial resistance genes (ARGs) and CRISPR arrays. The blast analysis with phylogeny revealed that vB_PmeS_STP12 is genetically similar to Pseudomonas phage PMBT14, Pseudomonas phage Almagne and Serratia phage Serbin with a highest identity of 74.00%, 74.93% and 59.48% respectively.
Taken together, characterization, morphological analysis and genome-informatics indicated that vB_PmeS_STP12 is podovirus morphotype belonging to the class Caudoviticetes, family Zobellviridae which appeared to be devoid of integrase gene, ARGs, CRISPR arrays, virulence factors and toxins genes, exhibiting stability and infectivity at wide range of pH (4 to10) and temperature (-20 to 70 °C), thereby making vB_PmeS_STP12 suitable for phage therapy or biocontrol. Based on the bibliometric analysis and data availability with respect to sequences deposited in GenBank, this is the first report of a phage infecting Pseudomonas mendocina.
从印度 Lovely Professional 大学污水处理厂未处理的地点，用假单胞菌 Mendocina 菌株 STP12（假单胞菌 Mendocina）分离出一种新型溶菌噬菌体（噬菌体）。假单胞菌 Mendocina 是一种革兰氏阴性、杆状、需氧细菌，属于假单胞菌科，已在全球 15 例具有重要经济意义的疾病中报道过。
在这里，使用富集、点测试和双层琼脂覆盖（DAOL）方法从污水样本中分离出一种专门感染和杀死假单胞菌 Mendocina 菌株 STP12 的新型噬菌体，并将其命名为 vB_PmeS_STP12。噬菌体 vB-PmeS-STP12 在 pH 值为 4 至 10 和 -20 至 70°C 的宽范围内具有活性。宿主范围和效价分析表明，噬菌体 vB-PmeS-STP12 能够感染和杀死假单胞菌 Mendocina 菌株 STP6，效价为 0.34。噬菌体 vB_PmeS_STP12 在所有给药剂量下均表现出显著的细菌减少（p<0.005），与对照组相比，特别是在最佳 MOI 为 1 PFU/CFU 时。使用高分辨率透射电子显微镜（HR-TEM）进行的形态分析显示，平均直径约为 55nm 的二十面体衣壳带有一个短的、不可收缩的尾巴。vB_PmeS_STP12 的基因组是一条线性、双链 DNA，大小为 36,212bp，GC 含量为 58.87%，包含 46 个开放阅读框（ORFs）。46 个预测的 ORF 编码具有功能信息的蛋白质，可分为裂解、复制、包装、调节、组装、感染、免疫和假设。然而，vB_PmeS_STP12 的基因组似乎缺乏 tRNA、整合酶基因、毒素基因、毒力因子、抗微生物耐药基因（ARGs）和 CRISPR 阵列。与系统发育的 Blast 分析表明，vB_PmeS_STP12 在遗传上与假单胞菌噬菌体 PMBT14、假单胞菌噬菌体 Almagne 和弧菌噬菌体 Serbin 相似，最高同源性分别为 74.00%、74.93%和 59.48%。
综上所述，特征描述、形态分析和基因组信息学表明，vB_PmeS_STP12 是一种 Podovirus 形态，属于 Caudoviticetes 类，家族 Zobellviridae，似乎缺乏整合酶基因、ARGs、CRISPR 阵列、毒力因子和毒素基因，在 pH 值为 4 至 10 和温度为-20 至 70°C 的宽范围内表现出稳定性和感染力，从而使 vB_PmeS_STP12 适合噬菌体治疗或生物控制。根据文献计量分析和 GenBank 中已存入序列的可用性，这是首例感染假单胞菌 Mendocina 的噬菌体报告。
