Kernodle D S, McGraw P A, Barg N L, Menzies B E, Voladri R K, Harshman S
Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
J Infect Dis. 1995 Aug;172(2):410-9. doi: 10.1093/infdis/172.2.410.
The morbidity and mortality of Staphylococcus aureus infections remain high despite antibiotic therapy. To investigate further the observation that penicillins increase the hemolytic activity of staphylococcal cultures, 37 strains were grown in broth with and without subinhibitory nafcillin. Nafcillin stimulated hemolytic activity in nafcillin-susceptible and -resistant isolates. Sterile broth filtrates of nafcillin-associated cultures injected intraperitoneally in mice were more rapidly lethal than filtrates of the same strain grown without nafcillin. Lethality was neutralized by anti-alpha-toxin antisera. DNA-RNA hybridization revealed a nafcillin-associated increase in alpha-toxin mRNA during the postexponential growth phase after the activation of agr. Isolates grown in slightly inhibitory nafcillin concentrations had more alpha-toxin mRNA than did nafcillin-free cultures, whereas agr RNAIII levels were comparable. This suggests that nafcillin-induced alpha-toxin production is not entirely attributable to agr. A supplemental regulatory mechanism may be involved.
尽管采用了抗生素治疗，金黄色葡萄球菌感染的发病率和死亡率仍然很高。为了进一步研究青霉素会增加葡萄球菌培养物溶血活性这一现象，在含有和不含有亚抑制浓度萘夫西林的肉汤中培养了37株菌株。萘夫西林刺激了对萘夫西林敏感和耐药菌株的溶血活性。将与萘夫西林相关的培养物的无菌肉汤滤液腹腔注射到小鼠体内，其致死速度比在没有萘夫西林的情况下培养的同一菌株的滤液更快。致死性可被抗α毒素抗血清中和。DNA-RNA杂交显示，在agr激活后的指数生长后期，萘夫西林会使α毒素mRNA增加。在略有抑制作用的萘夫西林浓度下生长的菌株比无萘夫西林培养的菌株有更多的α毒素mRNA，而agr RNAIII水平相当。这表明萘夫西林诱导的α毒素产生并不完全归因于agr。可能涉及一种补充调节机制。
