Nasal carriage of Staphylococcus aureus in healthy humans with different levels of contact with animals in Tunisia: genetic lineages, methicillin resistance, and virulence factors

Eur J Clin Microbiol Infect Dis. 2011 Apr;30(4):499-508. doi: 10.1007/s10096-010-1109-6. Epub 2010 Nov 11.

Abstract

Nasal swabs of 423 healthy humans who showed different levels of contact with animals (frequent, 168; sporadic, 94; no contact, 161) were obtained in Tunisia (2008-2009), and 99 of them presented other associated risk factors. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in one of these 423 samples (0.24%), retrieved from a veterinarian. The MRSA isolate was mecA-positive, typed as ST80-t203-SCCmecIVc-agrIII, and contained tet(K), ant(6)-Ia, and aph(3')-IIIa genes encoding tetracycline, streptomycin, and kanamycin resistance, respectively. This MRSA isolate also contained the lukF/lukS virulence gene encoding Panton-Valentine leukocidin. Fifty-four (12.8%) additional nasal samples contained methicillin-susceptible S. aureus (MSSA) and one isolate/sample was characterized. A high diversity of spa types (n = 43; 4 new) and pulsed-field gel electrophoresis (PFGE) types (n = 37) was detected among the 55 recovered S. aureus strains. The percentages of antimicrobial resistance/detected resistance genes were as follows: tetracycline [22%/tet(K)-tet(L)-tet(M)], erythromycin [5%/msrA], ciprofloxacin [14.5%], trimethoprim-sulfamethoxazole [2%/dfrA], streptomycin [11%/ant(6)-Ia], kanamycin [7%/aph(3')-IIIa], amikacin [5%], and chloramphenicol [2%]. Four and two isolates carried the lukF/lukS and eta and/or etb genes, respectively, and always in individuals with contact with animals. Eleven isolates carried the tst gene and were recovered from individuals with different levels of contact with animals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Proteins / genetics
  • Bacterial Typing Techniques
  • Carrier State / epidemiology*
  • Carrier State / microbiology
  • Drug Resistance, Multiple, Bacterial / genetics
  • Electrophoresis, Gel, Pulsed-Field
  • Humans
  • Methicillin / pharmacology
  • Methicillin Resistance / genetics
  • Methicillin-Resistant Staphylococcus aureus / drug effects
  • Methicillin-Resistant Staphylococcus aureus / genetics
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification*
  • Methicillin-Resistant Staphylococcus aureus / pathogenicity
  • Microbial Sensitivity Tests
  • Nasal Mucosa / microbiology*
  • Risk Factors
  • Staphylococcal Infections / epidemiology*
  • Staphylococcal Infections / microbiology
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / isolation & purification*
  • Staphylococcus aureus / pathogenicity
  • Tunisia / epidemiology
  • Virulence
  • Virulence Factors / genetics*

Substances

  • Bacterial Proteins
  • Virulence Factors
  • Methicillin