Laboratoire des Microorganismes et Biomolécules Actives, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Tunis, Tunisie.
Institut Supérieur des Sciences Biologiques Appliquées de Tunis, Université de Tunis El Manar, 2092 Tunis, Tunisie.
Sci Rep. 2017 Jan 16;7:40349. doi: 10.1038/srep40349.
Bacteriophages display remarkable genetic diversity and host specificity. In this study, we explore phages infecting bacterial strains of the Enterobacteriaceae family because of their ability to infect related but distinct hosts. We isolated and characterized two novel virulent phages, SH6 and SH7, using a strain of Shigella flexneri as host bacterium. Morphological and genomic analyses revealed that phage SH6 belongs to the T1virus genus of the Siphoviridae family. Conversely, phage SH7 was classified in the T4virus genus of the Myoviridae family. Phage SH6 had a short latent period of 16 min and a burst size of 103 ± 16 PFU/infected cell while the phage SH7 latent period was 23 min with a much lower burst size of 26 ± 5 PFU/infected cell. Moreover, phage SH6 was sensitive to acidic conditions (pH < 5) while phage SH7 was stable from pH 3 to 11 for 1 hour. Of the 35 bacterial strains tested, SH6 infected its S. flexneri host strain and 8 strains of E. coli. Phage SH7 lysed additionally strains of E. coli O157:H7, Salmonella Paratyphi, and Shigella dysenteriae. The broader host ranges of these two phages as well as their microbiological properties suggest that they may be useful for controlling bacterial populations.
噬菌体表现出显著的遗传多样性和宿主特异性。在这项研究中，我们探索了感染肠杆菌科细菌菌株的噬菌体，因为它们能够感染相关但不同的宿主。我们使用福氏志贺菌作为宿主细菌分离和表征了两种新型毒性噬菌体 SH6 和 SH7。形态学和基因组分析表明，噬菌体 SH6 属于肌尾噬菌体科 T1 病毒属。相反，噬菌体 SH7 被归类为肌尾噬菌体科 T4 病毒属。噬菌体 SH6 的潜伏期短，为 16 分钟，爆发量为 103±16PFU/感染细胞，而噬菌体 SH7 的潜伏期为 23 分钟，爆发量低得多，为 26±5PFU/感染细胞。此外，噬菌体 SH6 对酸性条件（pH<5）敏感，而噬菌体 SH7 在 pH3 到 11 之间稳定 1 小时。在测试的 35 株细菌中，SH6 感染其福氏志贺菌宿主菌株和 8 株大肠杆菌。噬菌体 SH7 还裂解了大肠杆菌 O157:H7、副伤寒沙门氏菌和痢疾志贺氏菌的菌株。这两种噬菌体更广泛的宿主范围及其微生物学特性表明，它们可能有助于控制细菌种群。
