Santos Thiago M A, Ledbetter Eric C, Caixeta Luciano S, Bicalho Marcela L S, Bicalho Rodrigo C
Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Am J Vet Res. 2011 Aug;72(8):1079-86. doi: 10.2460/ajvr.72.8.1079.
To isolate and characterize bacteriophages with strong in vitro lytic activity against various pathogenic Pseudomonas aeruginosa strains isolated from dogs with ocular infections.
26 genetically distinct P aeruginosa isolates.
P aeruginosa strains were derived from dogs with naturally acquired ulcerative keratitis. From a large-scale screening for bacteriophages with potential therapeutic benefit against canine ocular infections, 2 bacteriophages (P2S2 and P5U5) were selected; host ranges were determined, and phage nucleic acid type and genetic profile were identified via enzymatic digestion. Electron microscopy was used to characterize bacteriophage ultrastructure. Bacteriophage temperature and pH stabilities were assessed by use of double-layer agar overlay titration. A cocultivation assay was used to evaluate the effect of the bacteriophages on bacterial host growth.
P5U5 was active against all P aeruginosa isolates, whereas P2S2 formed lytic plaques on plates of 21 (80.8%) isolates. For each bacteriophage, the genomic nucleic acid was DNA; each was genetically distinct. Ultrastructurally, P2S2 and P5U5 appeared likely to belong to the Podoviridae and Siphoviridae families, respectively. The bacteriophages were stable within a pH range of 4 to 12; however, titers of both bacteriophages decreased following heating for 10 to 50 minutes at 45° or 60°C. Growth of each P aeruginosa isolate was significantly inhibited in coculture with P2S2 or P5U5; the dose response was related to the plaque-forming unit-to-CFU ratios.
Bacteriophages P2S2 and P5U5 appear to be good candidates for phage treatment of infection caused by pathogenic P aeruginosa in dogs.
分离并鉴定对从患有眼部感染的犬只中分离出的多种致病性铜绿假单胞菌菌株具有强大体外裂解活性的噬菌体。
26株基因不同的铜绿假单胞菌分离株。
铜绿假单胞菌菌株源自患有自然获得性溃疡性角膜炎的犬只。通过大规模筛选对犬眼部感染具有潜在治疗益处的噬菌体，选择了2种噬菌体（P2S2和P5U5）；确定宿主范围，并通过酶切鉴定噬菌体核酸类型和基因图谱。使用电子显微镜对噬菌体超微结构进行表征。通过双层琼脂覆盖滴定法评估噬菌体的温度和pH稳定性。采用共培养试验评估噬菌体对细菌宿主生长的影响。
P5U5对所有铜绿假单胞菌分离株均有活性，而P2S2在21株（80.8%）分离株的平板上形成裂解斑。对于每种噬菌体，基因组核酸均为DNA；每种在基因上均不同。在超微结构上，P2S2和P5U5似乎分别属于短尾噬菌体科和长尾噬菌体科。噬菌体在pH值4至12的范围内稳定；然而，在45°或60°C加热10至50分钟后，两种噬菌体的效价均下降。与P2S2或P5U5共培养时，每种铜绿假单胞菌分离株的生长均受到显著抑制；剂量反应与噬菌斑形成单位与菌落形成单位的比率相关。
噬菌体P2S2和P5U5似乎是用于噬菌体治疗犬致病性铜绿假单胞菌感染的良好候选者。
