title: Prevalence of antiseptic-resistance genes in staphylococci isolated from orthokeratology lens and spectacle wearers in Hong Kong.
abstract: OBJECTIVE
  To compare isolation of staphylococci from periorbital tissues and accessories of orthokeratology (ortho-k) lens and spectacle wearers and investigate prevalence of antiseptic-resistance (QAC) genes. To determine minimum inhibitory concentrations (MIC) of antiseptics and antibiotic susceptibility of isolates.
  
  
  METHODS
  Staphylococci were isolated from eyelids, eyelashes, and conjunctival sacs of 23 ortho-k lens wearers and 20 spectacle wearers. Samples were also collected from ortho-k lenses, lens cases, and spectacle frames. Isolations of Staphylococcus aureus were compared between ortho-k subjects and controls for all samples and for coagulase-negative staphylococci (CNS) from conjunctival sacs. QAC genes were amplified in 110 S. aureus and 59 CNS isolates and prevalence compared in isolates from ortho-k lens and spectacle wearers. Associations were assessed between presence of QAC genes and antibiotic and antiseptic susceptibility.
  
  
  RESULTS
  Although isolation of S. aureus did not differ significantly in periorbital samples from ortho-k and control subjects, QAC genes were significantly more common in both S. aureus and CNS from ortho-k subjects (odds ratio 4.4 and 10.74, respectively). Overall, qacA/B was the predominant gene detected, being present in 26.5% CNS and 11% S. aureus. smr and qacH were present in 12% of CNS, but were less common in S. aureus. QAC gene-positive isolates had higher MICs to benzalkonium chloride and chlorhexidine digluconate.
  
  
  CONCLUSIONS
  Our results suggest that long-term use of multipurpose solutions containing quaternary ammonium compounds may select for carriage of organisms harboring QAC genes. As these genes are associated with antibiotic resistance, their increased prevalence in isolates from contact lens wearers is a concern.
authors: School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR.
authors: Guang-sen
authors: GS
authors: Shi
authors: Squina Centre for Infection Control, School of Nursing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR.
authors: Maureen
authors: M
authors: Boost
authors: School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR 2Squina Centre for Infection Control, School of Nursing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR.
authors: Pauline
authors: P
authors: Cho
mesh_terms: D000293:Adolescent; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D017920:Antiporters / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001548:Benzalkonium Compounds / Q000494:pharmacology; D002648:Child; D002710:Chlorhexidine / Q000031:analogs & derivatives / Q000494:pharmacology; D003261:Contact Lenses / Q000382:microbiology*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005139:Eyeglasses / Q000382:microbiology*; D005260:Female; D006801:Humans; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D054158:Orthokeratologic Procedures; D015995:Prevalence; D013203:Staphylococcal Infections / Q000453:epidemiology*; D013211:Staphylococcus aureus / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000891:Anti-Infective Agents, Local; D017920:Antiporters; D001426:Bacterial Proteins; D001548:Benzalkonium Compounds; D026901:Membrane Transport Proteins; C010882:chlorhexidine gluconate; D002710:Chlorhexidine