Du Bois S K, Davison A L, Pinney R J
Department of Pharmaceutics, School of Pharmacy, University of London, UK.
J Pharm Pharmacol. 1995 Mar;47(3):193-6. doi: 10.1111/j.2042-7158.1995.tb05777.x.
Minimum inhibitory concentrations (MICs) of seven independent isolates of Staphylococcus hominis isolated in the same week from used eye-drops, preserved with thiomersal and collected from wards and clinics in the same hospital, ranged between 1 and 0.03 mg L-1 for thiomersal, 1 and 0.01 mg L-1 for phenyl mercuric nitrate and 10 and 3 mg L-1 for mercuric chloride. Although MIC values determined on solid nutrient medium indicated a 100-fold variation in susceptibility to the bacteriostatic effect of phenyl mercuric nitrate, after 5 h in an aqueous solution containing the bactericidal concentration of 10 mg L-1 phenyl mercuric nitrate, the survival levels of the six S. hominis isolates were similar, with a mean of 13.4% (s.d. 11.0), compared with 100 and 0.8%, respectively, for the most resistant and most sensitive control staphylococcal strains tested. Antibiotic susceptibilities and plasmid profiles of the S. hominis isolates indicated they were the same strain. It is concluded that laboratory indicators of preservative efficacy, such as MIC determination or susceptibility to bactericidal concentrations of preservatives, do not necessarily correlate with the epidemiology of contaminating bacterial strains or their survival in preserved pharmaceuticals.
从同一家医院病房和诊所收集的、用硫柳汞保存的用过的滴眼剂中，在同一周内分离出的7株独立的人葡萄球菌菌株，其对硫柳汞的最低抑菌浓度（MICs）在1至0.03 mg L-1之间，对硝酸苯汞的MICs在1至0.01 mg L-1之间，对氯化汞的MICs在10至3 mg L-1之间。尽管在固体营养培养基上测定的MIC值表明对硝酸苯汞抑菌作用的敏感性有100倍的差异，但在含有杀菌浓度10 mg L-1硝酸苯汞的水溶液中5小时后，6株人葡萄球菌菌株的存活水平相似，平均为13.4%（标准差11.0），而测试的最耐药和最敏感的对照葡萄球菌菌株的存活水平分别为100%和0.8%。人葡萄球菌菌株的抗生素敏感性和质粒图谱表明它们是同一菌株。得出的结论是，防腐剂效力的实验室指标，如MIC测定或对防腐剂杀菌浓度的敏感性，不一定与污染细菌菌株的流行病学或它们在保存药品中的存活情况相关。
