Knoetze H, Todorov S D, Dicks L M T
Department of Microbiology, University of Stellenbosch, Stellenbosch 7600, South Africa.
Int J Antimicrob Agents. 2008 Mar;31(3):228-34. doi: 10.1016/j.ijantimicag.2007.10.010. Epub 2007 Dec 26.
Peptide ST4SA, produced by Enterococcus mundtii ST4SA, inhibits the growth of Acinetobacter baumannii, Enterococcus faecalis, Enterococcus faecium, Staphylococcus aureus, Streptococcus pneumoniae and Gram-positive bacteria isolated from patients diagnosed with middle ear infections. The peptide adsorbed at a level of 94% to S. pneumoniae 40, Pseudomonas aeruginosa 25 and E. faecium HKLHS. Low concentrations of peptide ST4SA (51200 arbitrary units (AU)/mL) caused DNA and enzyme leakage from target cells, whilst 1638400AU/mL caused cell lysis. No decrease in antimicrobial activity was observed when tested on solid medium with human blood as base. Peptide ST4SA revealed a similar level of activity compared with tetracycline (30 microg), but much higher activity compared with nasal sprays, aminoglycosides, cephalosporins, fluoroquinolones, lincosamides, macrolides, nitroimidazole, penicillin, quinolones, sulphonamides, chloramphenicol, furazolidone, fusidic acid, rifampicin, trimethoprim, trimethoprim/sulfamethoxazole and vancomycin when tested in vitro. Peptide ST4SA dissipates the proton-motive force and may be used in the treatment of multidrug-resistant strains where antibiotics are excluded from cells by efflux pumps dependent on the membrane proton gradient.
蒙氏肠球菌ST4SA产生的肽ST4SA可抑制鲍曼不动杆菌、粪肠球菌、屎肠球菌、金黄色葡萄球菌、肺炎链球菌以及从诊断为中耳感染的患者中分离出的革兰氏阳性菌的生长。该肽对肺炎链球菌40、铜绿假单胞菌25和屎肠球菌HKLHS的吸附水平为94%。低浓度的肽ST4SA（51200任意单位（AU）/mL）会导致靶细胞的DNA和酶泄漏，而1638400AU/mL会导致细胞裂解。以人血为基础在固体培养基上进行测试时，未观察到抗菌活性降低。与四环素（30微克）相比，肽ST4SA显示出相似的活性水平，但在体外测试时，与鼻喷雾剂、氨基糖苷类、头孢菌素类、氟喹诺酮类、林可酰胺类、大环内酯类、硝基咪唑类、青霉素类、喹诺酮类、磺胺类、氯霉素、呋喃唑酮、夫西地酸、利福平、甲氧苄啶、甲氧苄啶/磺胺甲恶唑和万古霉素相比，其活性要高得多。肽ST4SA可消耗质子动力，可用于治疗多药耐药菌株，在这些菌株中，抗生素通过依赖膜质子梯度的外排泵被排出细胞。
