Nakamura Tomohiro, Kitana Junya, Fujiki Jumpei, Takase Masayuki, Iyori Keita, Simoike Kenta, Iwano Hidetomo
Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan.
ELMS Animal Medical Center, Suginami City, Japan.
Front Med (Lausanne). 2020 Jun 10;7:234. doi: 10.3389/fmed.2020.00234. eCollection 2020.
The spread of antibiotic-resistant bacteria (ARB) in human and veterinary medicine is of global concern. Notably, the emergence of methicillin-resistant has become a serious problem. In this context, bacteriophages and their lytic enzymes, endolysins, have received considerable attention as therapeutics for infectious diseases in place of antibiotics. The aim of the present study was to investigate the antibiotic-resistance patterns of staphylococcal species isolated from canine skin at a primary care animal hospital in Tokyo, Japan and evaluate the lytic activity of the staphylococcal bacteriophage phiSA012 and its endolysin Lys-phiSA012 against isolated antibiotic-resistant staphylococcal strains. Forty clinical staphylococcal samples were isolated from infection sites of dogs (20 from skin and 20 from the external ear canal). Susceptibility to antimicrobial agents was determined by a disk diffusion method. The host range of phiSA012 was determined by using a spot test against staphylococcal isolates. Against staphylococcal isolates that showed resistance toward five classes or more of antimicrobials, the lytic activity of phiSA012 and Lys-phiSA012 was evaluated using a turbidity reduction assay. Twenty-three , 16 , and 1 were detected from canine skin and ear infections, and results revealed 43.5% methicillin resistance in and 31.3% in . In addition, the prevalence multidrug resistance (MDR) was 65.2%. PhiSA012 could infect all staphylococcal isolates by spot testing, but showed little lytic activity by turbidity reduction assay against MDR isolates. On the other hand, Lys-phiSA012 showed lytic activity and reduced significantly the number of staphylococcal colony-forming units. These results demonstrated that ARB issues underlying in small animal hospital and proposed substitutes for antibiotics. Lys-phiSA012 has broader lytic activity than phiSA012 against staphylococcal isolates; therefore, Lys-phiSA012 is a more potential candidate therapeutic agent for several staphylococcal infections including that of canine skin.
抗生素耐药菌（ARB）在人类医学和兽医学中的传播是全球关注的问题。值得注意的是，耐甲氧西林菌的出现已成为一个严重问题。在这种背景下，噬菌体及其裂解酶（内溶素）作为替代抗生素治疗传染病的手段受到了相当大的关注。本研究的目的是调查从日本东京一家初级保健动物医院的犬类皮肤分离出的葡萄球菌属的抗生素耐药模式，并评估葡萄球菌噬菌体phiSA012及其内溶素Lys-phiSA012对分离出的耐抗生素葡萄球菌菌株的裂解活性。从犬类感染部位分离出40份临床葡萄球菌样本（20份来自皮肤，20份来自外耳道）。通过纸片扩散法测定对抗菌剂的敏感性。通过对葡萄球菌分离株进行点试验来确定phiSA012的宿主范围。针对对五类或更多类抗菌药物表现出耐药性的葡萄球菌分离株，使用浊度降低试验评估phiSA012和Lys-phiSA012的裂解活性。从犬类皮肤和耳部感染中检测到23株、16株和1株，结果显示中耐甲氧西林率为43.5%，中为31.3%。此外，多重耐药（MDR）的患病率为65.2%。通过点试验，phiSA012可以感染所有葡萄球菌分离株，但通过浊度降低试验对MDR分离株的裂解活性很小。另一方面，Lys-phiSA012表现出裂解活性，并显著减少了葡萄球菌菌落形成单位的数量。这些结果证明了小动物医院中存在的ARB问题，并提出了抗生素的替代物。Lys-phiSA012对葡萄球菌分离株的裂解活性比phiSA012更广泛；因此，Lys-phiSA012是治疗包括犬类皮肤感染在内的几种葡萄球菌感染的更具潜力的候选治疗剂。
