Antibiotic resistance spectrum and genetic characteristics of MDRSA nasal isolate among primary school students

Abstract

Objective To investigate the antibiotic resistance spectrum and genetic characteristics of multidrug-resistant Staphylococcus aureus (MDRSA) nasal isolate among primary school students, and to provide a scientific basis for the prevention and control of masal MDRSA resistance and the selection of clincal drugs in children.

Methods Antibiotic susceptibility experiments were performed on all SA isolates of 1 705 primary school students from 8 primary schools in Guangzhou selected by using multistage cluster stratified sampling method. MDRSA antibiotic susceptibility spectrum was analyzed, and the resistant, virulence and immune evasion cluster ( IEC) genes detected by polymerase chain reaction (PCR) .

Results The prevalence of MDRSA nasal carriage was 20.76%(354/1 705), and the proportion of multidrug resistance among SA isolates was 96.20% (354/368). The predominant resistant antibiotics of MDRSA isolates were penicillin (99.72%), erythromycin (96.33%), clindamycin (90.96%) and teicoplanin (90.11%). Notably, 240(67.80%, 240/354) MDRSA isolates were resistant to more than six antimicrobial categories. And the predominant detection rates of resistant genes were BlaZ (92.66%), Tet(M) (49.72%), virulence genes Tst (25.42%) and IEC genes Sak (92.09%), Hlb (61.58%).

Conclusion We found high prevalence of nasal colonization MDRSA from healthy children. Moreover, MDRSA isolates has a high resistant rate to multiple antibiotics, and the proportion of resistant to ≥ 6 antimicrobial categories is high.

Abstract

【摘要】 目的 探究小学生鼻腔多重耐药金黄色葡萄球菌（multidmg-resistant staphylococcus aureus, MDRSA)的耐药 谱和基因携带特征，为预防和控制儿童鼻腔MDRSA耐药产生及临床用药的选择提供科学依据。 方法采用多阶段分层 整群抽样方法，抽取广州市8所小学1 705名小学生，对儿童鼻腔分离鉴定出的金黄色葡萄球菌（SA)进行药物敏感实验， 分析MDRSA的耐药谱，用多重聚合酶链式反应（PCR)技术测定耐药、毒素和免疫逃避（immune evasion cluster， IEC)基因。 结果 MDRSA 携带率为 20.76%(354/1 705)，MDRSA 占 SA 的比例为 96.20%(354/368)。MDRSA 对青霉素（99.72%)、红 霉素（96.33%)、克林霉素（90.96%)和替考拉宁（90.11%)的耐药率髙，同时对6类及以上抗生素耐药率为67.80%(240/ 354)。主要携带耐药基因 BlaZ (92.66%)、 Tet ( M) (49.72%)，毒素基因 Tst (25.42%)，IEC 基因 Sak (92.09%)和 Hlb (61.58%)。结论健康儿童鼻腔MDRSA携带率较髙，MDRSA对多种抗生素有髙耐药率，且耐药类别≥6的比例髙。