Community and hospital acquired methicillin resistant Staphylococcus aureus efficiently retain the Van A determinant

作     者：Anup Kainthola Ajay B. Bhatt Ashish Gupta 

作者机构：Laboratory of Microbiology Department of Botany & Microbiology HNB Garhwal Central University Uttarakhand 246174 India School of Biotechnology Amity International University NOIDA UP India 

出 版 物：《Frontiers in Biology》 (生物学前沿（英文版）)

年 卷 期：2015年第10卷第6期

页      面：520-527页

核心收录：

学科分类：090603[农学-临床兽医学] 09[农学] 0906[农学-兽医学] 0903[农学-农业资源与环境] 

基　　金：University Grants Commission, UGC ABB 

主　　题：Van A resistance MRSA fitness growth kinetics resistance transfer 

摘      要：Dissemination of vancomycin resistance from hospital to community strains is a serious threat to public health. Our study aimed to provide evidence for transmission of Van A type resistance from the hospital to the community. Wild-type community and hospital associated methicillin resistant Staphylococcus aureus strains were studied in vitro and in a model that mimicked a natural environment to ascertain their ability to acquire and maintain the vancomycin resistance determinant （Van A gene） from vancomycin resistant Enterococcus faecalis. Fitness was assessed and the cost of Van A acquisition and retention was estimated. In vitro mating experiments were carried out using a filter mating technique and a model of a natural water body environment. Transfer of resistance was carried out in two different conditions： restricted and favorable. Transconjugants were confirmed by E test and PCR using specific primer sets. Growth kinetics and fitness measurements were done by spectrometric analysis. Using the in vitro filter mating technique, high transfer frequencies that ranged from 0.7 × 10^-3（0.0006） to 3.1 ×10^-4（0.00011） were recorded, with the highest transfer frequencies for CA MRSA （thermosensitively homogenous） （0.7 × 10^- 3）, and 1.2 × 10^-4 to 2.4 × 10^-4 in the model. HA MRSA （homogenous） showed a greater capacity （3.6 ×10^-4） to receive the Van A gene, while CA MRSA showed a reduced ability to maintain the gene after serial subcultures. CA and HA thermosensitively heterogeneous MRSA transconjugants exhibited higher growth rates. The present study provides evidence for the enhanced ability of CA and HA MRSA clones to acquire and maintain Van A type resistance.