Dissemination of macrolides, fusidic acid and mupirocin resistance among <i>Staphylococcus aureus</i> clinical isolates

Abstract

// Xingmei Liu 1, * , Shanshan Deng 2, * , Jinwei Huang 3 , Yaling Huang 1 , Yu Zhang 1 , Qin Yan 1 , Yanhong Wang 1 , Yanyue Li 1 , Chengfu Sun 1 and Xu Jia 1 1 Non-Coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu 610500, China 2 School of Laboratory Medicine, Chengdu Medical College, Chengdu 610500, China 3 Institute of Antibiotics, The Fifth Affiliated Hospital, Wenzhou Medical University, Lishui 323000, China * These authors have contributed equally to this work Correspondence to: Chengfu Sun, email: chengfu.sun@cmc.edu.cn Xu Jia, email: jiaxu@cmc.edu.cn Keywords : Staphylococcus aureus , macrolides, fusidic acid (FA), mupirocin, resistance Received: May 04, 2017&emsp;&emsp;&emsp;&emsp; Accepted: June 19, 2017&emsp;&emsp;&emsp;&emsp; Published: July 22, 2017 ABSTRACT As an increasingly common cause of skin infections worldwide, the prevalence of antibiotic-resistant Staphylococcus aureus ( S. aureus ) across China has not been well documented. This literature aims to study the resistance profile to commonly used antibiotics, including macrolides, fusidic acid (FA) and mupirocin, and its relationship to the genetic typing in 34 S. aureus strains, including 6 methicillin-resistant S. aureus (MRSA), isolated from a Chinese hospital. The MIC results showed 27 (79.4%), 1 (2.9%) and 6 (17.6%) isolates were resistant to macrolides, FA and mupirocin, respectively. Among 27 macrolide-resistant S. aureus isolates, 5 (18.5%) were also resistant to mupirocin and 1 (3.7%) to FA. A total of 13 available resistant genes were analyzed in 28 antibiotic-resistant strains using polymerase chain reaction (PCR). The positive rates of macrolide-resistant ermA , ermB , ermC , erm33 and low level mupirocin-resistant ileS mutations were 11.1%, 25.9%, 51.9%, 7.4% and 100%, respectively. Other determinants for FA- and high level mupirocin-resistance were not found. The results of multilocus sequence typing (MLST) and pulsed field gel electrophoresis (PFGE) revealed 13 sequence types (STs) and 18 clusters in 23 resistant gene positive S. aureus isolates. Among these STs, ST5 was most prevalent, accounting for 18.2%. Notably, various clusters were found with similar resistance phenotype and genotype, exhibiting a weak genetic relatedness and high genetic heterogeneities. In conclusion, macrolides, especially erythromycin, are not appropriate to treat skin infections caused by S. aureus , and more effective measures are required to reduce the dissemination of macrolides, FA and mupirocin resistance of the pathogen.