College of Veterinary Medicine, Nanjing Agricultural University, No.1 Weigang, Xuanwu District Nanjing City, 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, No.1 Weigang, Xuanwu District Nanjing City, 210095, China; OIE Reference Lab for Swine Streptococcosis, No.1 Weigang, Xuanwu District Nanjing City, 210095, China; MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, No.1 Weigang, Xuanwu District Nanjing City, 210095, China.
Department of Clinical Laboratory, Nantong Third Hospital Affiliated to Nantong University, Nantong, Jiangsu 212006, China.
Virus Res. 2022 Jun;314:198750. doi: 10.1016/j.virusres.2022.198750. Epub 2022 Mar 18.
In recent years, Klebsiella pneumoniae has caused an increase in the number of serious infections associated with pneumonia, septicemia, urinary tract infections, and pyogenic liver abscess. In this study, a phage P929, isolated from hospital sewage in Jiangsu, could specifically infect K. pneumoniae KL19 capsular type by forming plaques with a translucent halo that expanded over time. Phage P929 with a multiplicity of infection (MOI) of 0.1 produced the highest phage titer. According to a one-step growth curve experiment, the latent time period of phage P929 was 25 min, and the burst size was about 156 phage particles/cell. The sensitivity tests confirmed that P929 was stable at temperatures ranging from 4 to 50 °C and pH 3 to 11. Based on morphological observation and phylogenetic analysis, phage P929 could be assigned to a new species in the genus Drulisvirus of the subfamily Slopekvirinae in the family Autographiviridae. According to genome analysis, phage P929 was 44,764 bp in size with 53.66% G + C content, encoding 57 proteins or coding sequences (117-3699 bp in length). Phage P929 showed potential antibacterial activity on planktonic cells and biofilm. After 120 min, the OD600 values of five phage-treated groups were basically reached zero compared to the untreated group, and the antibacterial activity of P929 was still detectable within 390 min. In anti-biofilm tests, phage P929 at an MOI of 1 significantly reduced the biofilm formation of K. pneumoniae in 48 h. These results suggest that phage P929 may be used to treat carbapenem-resistant and biofilm-forming K. pneumonia in clinical settings.
近年来，肺炎克雷伯菌引起的严重感染数量不断增加，这些感染与肺炎、败血症、尿路感染和化脓性肝脓肿有关。在这项研究中，从江苏医院污水中分离到的噬菌体 P929，通过形成随时间扩大的半透明晕环噬菌斑，能够特异性感染肺炎克雷伯菌 KL19 荚膜型。噬菌体 P929 的感染复数（MOI）为 0.1 时产生的噬菌体效价最高。根据一步生长曲线实验，噬菌体 P929 的潜伏期为 25 分钟，爆发量约为 156 个噬菌体/细胞。敏感性测试证实，P929 在 4 至 50°C 和 pH 3 至 11 的温度下稳定。根据形态观察和系统发育分析，噬菌体 P929 可归入 Autographiviridae 科 Slopekvirinae 亚科 Drulisviruses 属的一个新种。根据基因组分析，噬菌体 P929 大小为 44764bp，G+C 含量为 53.66%，编码 57 种蛋白质或编码序列（长度为 117-3699bp）。噬菌体 P929 对浮游细胞和生物膜均显示出潜在的抗菌活性。与未处理组相比，在 120 分钟后，五个噬菌体处理组的 OD600 值基本达到 0，并且在 390 分钟内仍能检测到 P929 的抗菌活性。在抗生物膜试验中，噬菌体 P929 在 MOI 为 1 时可显著减少肺炎克雷伯菌在 48 小时内的生物膜形成。这些结果表明，噬菌体 P929 可能用于治疗临床中耐碳青霉烯类和形成生物膜的肺炎克雷伯菌。
