Multidrug-resistant clones of community-associated meticillin-resistant Staphylococcus aureus isolated from Chinese children and the resistance genes to clindamycin and mupirocin

J Med Microbiol. 2012 Sep;61(Pt 9):1240-1247. doi: 10.1099/jmm.0.042663-0. Epub 2012 May 17.

Abstract

This study aimed to correlate the multidrug resistance (MDR) and sequence type (ST) clones of community-associated (CA) meticillin-resistant Staphylococcus aureus (MRSA) to identify the genes responsible for clindamycin and mupirocin resistance in S. aureus isolates from paediatric hospitals in mainland China. A total of 435 S. aureus isolates were collected. Compared with CA meticillin-susceptible S. aureus (MSSA), the resistance rates of CA-MRSA to ciprofloxacin, chloramphenicol, gentamicin and tetracycline were higher (19.0 vs 2.6 %, P<0.001; 14.7 vs 3.1 %, P<0.001; 14.7 vs 3.1 %, P<0.01; and 46.0 vs 13.3 %, P<0.001, respectively). Compared with hospital-associated (HA)-MRSA, the resistance rates of CA-MRSA to ciprofloxacin, gentamicin, rifampicin, tetracycline and trimethoprim-sulfamethoxazole were lower (19 vs 94.8 %, P<0.001; 14.7 vs 84.4 %, P<0.001; 5.5 vs 88.3 %, P<0.001; 46 vs 94.8 %, P<0.001; and 1.8 vs 9.1 %, P<0.01, respectively). The resistance rates of CA-MRSA, HA-MRSA and CA-MSSA to clindamycin (92.0, 77.9 and 64.1 %, respectively) and erythromycin (85.9, 77.9 and 63.1 %, respectively) were high. The MDR rates (resistance to three or more non-β-lactams) were 49.6, 100 and 14 % in the CA-MRSA, HA-MRSA and CA-MSSA isolates, respectively. Five of seven ST clones in the CA-MRSA isolates, namely ST59, ST338, ST45, ST910 and ST965, had MDR rates of >50 % (67.9, 87.5, 100, 50 and 83.3 %, respectively). The constitutive phenotype of macrolide-lincosamide-streptogramin B (MLS(B)) resistance (69 %) and the ermB gene (38.1 %) predominated among the MLS(B)-resistant CA S. aureus strains. The resistance rate to mupirocin was 2.3 % and plasmids carrying the mupA gene varied in size between 23 and 54.2 kb in six strains with high-level resistance as determined by Southern blot analysis. The present study showed that resistance to non-β-lactams, especially to clindamycin, is high in CA-MRSA isolates from Chinese children and that the profile of resistance is related to clonal type. This study revealed distinctive patterns of MLS(B)-resistant genes among CA S. aureus isolates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Anti-Bacterial Agents / pharmacology*
  • Child
  • Child, Preschool
  • China
  • Clindamycin / pharmacology
  • Community-Acquired Infections / microbiology*
  • Drug Resistance, Multiple, Bacterial* / genetics
  • Humans
  • Infant
  • Infant, Newborn
  • Methicillin-Resistant Staphylococcus aureus / drug effects*
  • Methicillin-Resistant Staphylococcus aureus / genetics*
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification
  • Methicillin-Resistant Staphylococcus aureus / metabolism
  • Microbial Sensitivity Tests
  • Mupirocin / pharmacology
  • Sequence Analysis, DNA
  • Staphylococcal Infections / microbiology*
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / isolation & purification
  • Staphylococcus aureus / metabolism

Substances

  • Anti-Bacterial Agents
  • Clindamycin
  • Mupirocin