Inducibility and potential role of MecA-gene-positive oxacillin-susceptible Staphylococcus aureus from colonized healthcare workers as a source for nosocomial infections
Inducibility and potential role of MecA-gene-positive oxacillin-susceptible Staphylococcus aureus from colonized healthcare workers as a source for nosocomial infections
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DOI：
10.1016/s0195-6701(03)00119-1
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发表时间：
2003-06-01
影响因子：
6.9
通讯作者：
Weist, K
中科院分区：
文献类型：
--
作者：
Kampf, G;Adena, S;Weist, K
为了解医务人员中甲氧西林敏感的甲氧西林-甲氧西林阳性金黄色葡萄球菌(MRSA)携带率，对13个普通病房和重症监护病房的447名护士和医生进行鼻咽部调查。当一名MRSA患者接受治疗时，金黄色葡萄球菌在一年内携带。所有mecA阳性的苯唑西林敏感金黄色葡萄球菌均尝试用苯唑西林和头孢噻肟作用24小时来诱导其表型耐药。来自抗生素浓度最高且孵化后可见生长的肉汤管中的微生物被再次暴露，总共重复暴露7次。以2株甲氧西林阴性、苯唑西林敏感的金黄色葡萄球菌为阴性对照。对接触抗生素前后的人群进行了分析。三分之一的医务工作者被发现是金黄色葡萄球菌携带者。仅有3名护士MRSA阳性(0.7%)。6名护士和1名医生共分离出7株潜伏期MRSA(1.6%)。经过四天的重复抗生素暴露，七个休眠的MRSA中有六个对苯唑西林高度耐药。不携带mecA基因的两个对照金黄色葡萄球菌的耐药性不会因重复抗生素暴露而改变。脉冲场凝胶电泳法(PFGE)显示，7株休眠MRSA中有2株与克隆性相关。一株休眠MRSA(HCW)的PFGE图谱与一株MRSA(HCW)的PFGE图谱相同。另一种休眠的MRSA的模式与从同一病房同时接受治疗的患者分离的MRSA没有区别，表明从HCW向患者传播。从医务人员中分离出休眠的MRSA的频率可能是MRSA的两倍。传播给患者是可能的，这可能会导致临床感染。当病房反复发生MRSA感染且来源不明时，从医务工作者中筛选出mecA基因的甲氧西林敏感金黄色葡萄球菌可能是有用的。(C)2003年医院感染学会。爱思唯尔科学有限公司出版。版权所有。
To determine the carrier rate of methicillin-susceptible mecA-positive Staphylococcus aureus (dormant MRSA) among healthcare workers (HCWs), 447 nurses and physicians from 13 general wards and intensive care units were investigated for nasal or oropharyngeal. S. aureus carriage during one year whenever an MRSA patient was treated. Induction of phenotypic resistance in all mecA-positive oxacillin-susceptible aureus was attempted by 24 h exposure to oxaciltin and cefotaxime. Organisms from the broth tube with the highest antibiotic concentration and visible growth after incubation were re-exposed for a total of seven repetitive exposures. Two mecA-negative oxacillin-susceptible S. aureus served as negative control. A population analysis before and after antibiotic exposure was performed. A third of the HCWs were found to be S. aureus carriers. Only three nurses were MRSA positive (0.7%). Seven isolates of dormant MRSA were isolated in six nurses and one doctor (1.6%). After four days of repetitive antibiotic exposure six of seven dormant MRSA were highly resistant to oxacillin. Resistance of the two control S. aureus without the mecA gene was not changed by repetitive antibiotic exposure. Two of the seven dormant MRSA were clonally related as shown by pulsed-field get electrophoresis (PFGE). The PFGE pattern of one dormant MRSA (HCW) was identical to an MRSA (HCW). The pattern of another dormant MRSA was indistinguishable from an MRSA isolated from a patient who was treated at the same time on the same ward suggesting transmission from the HCW to the patient. Dormant MRSA may be isolated twice as often as MRSA from HCWs. Transmission to patients is possible, which may lead to clinical infections. It might be useful to screen methicillin-susceptibte S. aureus isolates from HCWs for the mecA gene when recurrent infections with MRSA occur on a ward and a source cannot be found. (C) 2003 The Hospital Infection Society. Published by Elsevier Science Ltd. All rights reserved.