title: Characteristics of qacA/B-positive Staphylococcus aureus isolated from patients and a hospital environment in China.
abstract: OBJECTIVE
  This study was designed to demonstrate the characteristics of qacA/B-positive Staphylococcus aureus in China.
  
  
  METHODS
  One hundred and forty-five MRSA and 178 MSSA from clinical specimens from seven hospitals in different regions of China, 70 MRSA from superficial sites of patients and 106 MRSA from environmental samples from an ICU were collected and screened for the presence of the qacA/B gene. The qacA/B-positive isolates and 72 randomly selected qacA/B-negative control isolates were further characterized by MLST, spa typing and detection of toxin genes, as well as antimicrobial and chlorhexidine susceptibility. SCCmec typing was conducted for MRSA. PFGE was conducted for qacA/B-positive isolates.
  
  
  RESULTS
  Twenty-five (7.8%) of the 321 MRSA isolates harboured qacA/B, including 11 isolates from clinical specimens (7.6%), 12 isolates from patients' superficial sites (17.1%) and 2 isolates from an ICU environment (1.9%). Ten and five qacA/B-positive MRSA were identified as ST239-t030-MRSA-III and ST239-t037-MRSA-III, respectively. Six PFGE clusters and five singletons were identified among the 25 qacA/B-positive MRSA. Only one (0.6%) of the 178 MSSA isolates harboured qacA/B. qacA/B carriage in MRSA was statistically associated with spa-t037 and the presence of mupA. Compared with qacA/B-negative MRSA, the qacA/B-positive MRSA exhibited a lower susceptibility to chlorhexidine and higher resistance rates to clindamycin and trimethoprim/sulfamethoxazole.
  
  
  CONCLUSIONS
  Carriage of qacA/B, although it had a low prevalence, might be the main reason for declining susceptibility to chlorhexidine in MRSA from Chinese patients and is probably associated with spa-t037 and the presence of the mupA gene.
authors.affiliation: Center for Hospital Infection Control, Chinese PLA Institute for Disease Control & Prevention, Academy of Military Medical Sciences, Beijing, China College of Food Science and Engineering, Shandong Agricultural University Shandong Agricultural University, Tai'an, China.
authors.forename: Zhongyi
authors.initials: Z
authors.lastname: Lu
authors.affiliation: Center for Hospital Infection Control, Chinese PLA Institute for Disease Control & Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: College of Food Science and Engineering, Shandong Agricultural University Shandong Agricultural University, Tai'an, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Surgical Intensive Care Unit, Chinese PLA General Hospital, Beijing, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Surgical Intensive Care Unit, Chinese PLA General Hospital, Beijing, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Song
authors.affiliation: Center for Hospital Infection Control, Chinese PLA Institute for Disease Control & Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Hu
authors.affiliation: Department of Clinical Laboratory, General Hospital of Chengdu Military Command, Chengdu, China.
authors.forename: Ziying
authors.initials: Z
authors.lastname: Zou
authors.affiliation: Department of Clinical Microbiology, Urumqi General Hospital of Lanzhou Military Command, PLA, Urumqi, China.
authors.forename: Zhengxiang
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Clinical Microbiology, The Second Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Libo
authors.initials: L
authors.lastname: Duo
authors.affiliation: Department of Clinical Microbiology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Jiyong
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Clinical Laboratory, General Hospital of Ji'nan Military Command, Ji'nan, China.
authors.forename: Yanwen
authors.initials: Y
authors.lastname: Gong
authors.affiliation: Department of Clinical Laboratory, 94 Hospital of PLA, Nanchang, China.
authors.forename: Zhanke
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China.
authors.forename: Xuqin
authors.initials: X
authors.lastname: Wu
authors.affiliation: Center for Hospital Infection Control, Chinese PLA Institute for Disease Control & Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Jingya
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Center for Hospital Infection Control, Chinese PLA Institute for Disease Control & Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Changjian
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Center for Hospital Infection Control, Chinese PLA Institute for Disease Control & Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Mengqiang
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Center for Hospital Infection Control, Chinese PLA Institute for Disease Control & Prevention, Academy of Military Medical Sciences, Beijing, China hanlicdc@163.com.
authors.forename: Li
authors.initials: L
authors.lastname: Han
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D002681:China; D002710:Chlorhexidine / Q000494:pharmacology; D002981:Clindamycin / Q000494:pharmacology; D016000:Cluster Analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D004783:Environmental Microbiology; D005798:Genes, Bacterial; D005838:Genotype; D060005:Genotyping Techniques; D006761:Hospitals; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; C099272:QacB protein, Staphylococcus aureus; C068498:qacA protein, Staphylococcus aureus; D002981:Clindamycin; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D002710:Chlorhexidine
keywords: S. aureus; antimicrobial resistance; chlorhexidine resistance; toxin genes