Staphylococcus aureus dry-surface biofilms are not killed by sodium hypochlorite: implications for infection control
Staphylococcus aureus dry-surface biofilms are not killed by sodium hypochlorite: implications for infection control
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DOI：
10.1016/j.jhin.2016.03.020
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发表时间：
2016-07-01
影响因子：
6.9
通讯作者：
Vickery, K.
中科院分区：
文献类型：
--
作者：
Almatroudi, A.;Gosbell, I. B.;Vickery, K.
目的：检测次氯酸钠溶液对金黄色葡萄球菌干表面生物膜的杀灭效果。方法：采用美国疾病控制与预防中心生物膜反应器，通过12天的生长和脱水交替循环，建立一种含1.36×10(7)金黄色葡萄球菌/片的干表面生物膜。用活/死染色共聚焦激光扫描显微镜(CLSM)定性检测生物膜，用超声活菌平板计数和结晶紫试验定量检测生物膜。将1000-20000 ppm的次氯酸钠作用于干表面生物膜10min，洗片3次，用激光共聚焦显微镜、平板计数和延长培养至16d检测剩余生物膜的活力。对暴露前后的分离株进行最低抑菌浓度(MIC)和最低根除浓度(MEC)测试，其中一对进行全基因组测序。结果：次氯酸盐暴露使平板数量减少了7log(10)倍，生物被膜生物量减少了100倍；然而，残留生物膜染色显示活的金黄色葡萄球菌细胞仍然存在。延长培养时间，金黄色葡萄球菌重新生长并形成生物膜。暴露后的金黄色葡萄球菌分离株的MIC和MECs与亲本株没有显著差异。对暴露前和暴露后的一对进行全基因组测序，发现它们实际上是相同的。结论：次氯酸盐暴露导致7对数死亡，但生物体重新出现。没有发生耐药性突变，这意味着次氯酸盐抗性是金黄色葡萄球菌生物被膜的一种固有特性。其临床意义值得进一步研究。(C)2016年医疗感染学会。爱思唯尔有限公司出版。保留所有权利。
Background: Dry hospital environments are contaminated with pathogenic bacteria in biofilms, which suggests that current cleaning practices and disinfectants are failing.Aim: To test the efficacy of sodium hypochlorite solution against Staphylococcus aureus dry-surface biofilms.Methods: The Centers for Disease Control and Prevention Biofilm Reactor was adapted to create a dry-surface biofilm, containing 1.36 x 10(7) S. aureus/coupon, by alternating cycles of growth and dehydration over 12 days. Biofilm was detected qualitatively using live/dead stain confocal laser scanning microscopy (CLSM), and quantitatively with sonicated viable plate counts and crystal violet assay. Sodium hypochlorite (1000-20,000 parts per million) was applied to the dry-surface biofilm for 10 min, coupons were rinsed three times, and residual biofilm viability was determined by CLSM, plate counts and prolonged culture up to 16 days. Isolates before and after exposure underwent minimum inhibitory concentration (MIC) and minimum eradication concentration (MEC) testing, and one pair underwent whole-genome sequencing.Findings: Hypochlorite exposure reduced plate counts by a factor of 7 log(10), and reduced biofilm biomass by a factor of 100; however, staining of residual biofilm showed that live S. aureus cells remained. On prolonged incubation, S. aureus regrew and formed biofilms. Post-exposure S. aureus isolates had MICs and MECs that were not significantly different from the parent strains. Whole-genome sequencing of one pre- and post-exposure pair found that they were virtually identical.Conclusions: Hypochlorite exposure led to a 7-log kill but the organisms regrew. No resistance mutations occurred, implying that hypochlorite resistance is an intrinsic property of S. aureus biofilms. The clinical significance of this warrants further study. (C) 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.