title: Methicillin-resistant Staphylococcus aureus biofilm formation on dacryocystorhinostomy silicone tubes depends on the genetic lineage.
abstract: OBJECTIVE
  The aim of this study was to investigate biofilm formation on silicone tubes by genetically diverse methicillin-resistant Staphylococcus aureus (MRSA) strains.
  
  
  METHODS
  Capacity of biofilm formation on dacryocystorhinostomy silicone tubes was tested on 30 MRSA strains. Identification and methicillin resistance were confirmed by PCR for nuc and mecA genes. Strains were genotypically characterised (SCCmec, agr and spa typing). Biofilm formation was tested in microtiter plate and on silicone tubes.
  
  
  RESULTS
  Tested MRSA strains were classified into SCCmec type I (33.3%), II (3.3%), III (20.0%), IV (26.7%) and V (16.7%), agr type I (56.7%), II (36.7%) and III (6.6%), and eight spa clonal complexes (CCs). All tested MRSA strains showed ability to form biofilm on microtiter plate. Capacity of biofilm formation on silicone tubes was as follows: 33.3% of strains belonged to the category of low biofilm producers, and 66.7% to moderate biofilm producers. There was statistically significant correlation between spa CC and the category of biofilm production on silicone tubes (p = 0.01): CC5 and CC45 with moderate amount of biofilm, and CC8 with low amount of biofilm. A moderate amount of biofilm formed on silicone tubes correlated with agr type II MRSA strains (p = 0.008).
  
  
  CONCLUSIONS
  Biofilm formation by MRSA on silicone tubes is highly dependent on genetic characteristics of the strains. Therefore, MRSA genotyping may aid the determination of the possibility of biofilm-related ocular device infections. Genotyping and biofilm quantification may be helpful in determining when decolonisation and cohort isolation are required to prevent device-related infections.
authors.affiliation: Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, Dr Subotića 1, Belgrade, 11000, Serbia, cirkoviciv@yahoo.com.
authors.forename: Ivana
authors.initials: I
authors.lastname: Ćirković
authors.forename: Miroslav
authors.initials: M
authors.lastname: Knežević
authors.forename: Dragana D
authors.initials: DD
authors.lastname: Božić
authors.forename: Dejan
authors.initials: D
authors.lastname: Rašić
authors.forename: Anders Rhod
authors.initials: AR
authors.lastname: Larsen
authors.forename: Slobodanka
authors.initials: S
authors.lastname: Đukić
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D018441:Biofilms / Q000254:growth & development*; D004269:DNA, Bacterial / Q000235:genetics*; D003608:Dacryocystorhinostomy / Q000295:instrumentation*; D005838:Genotype; D006801:Humans; D007440:Intubation / Q000295:instrumentation; D055624:Methicillin-Resistant Staphylococcus aureus / Q000502:physiology*; D008836:Micrococcal Nuclease / Q000235:genetics; D046915:Penicillin-Binding Proteins; D016133:Polymerase Chain Reaction; D016459:Prosthesis-Related Infections / Q000382:microbiology*; D012826:Silicone Elastomers; D015534:Trans-Activators / Q000235:genetics
chemical_list: C095698:Agr protein, Staphylococcus aureus; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D046915:Penicillin-Binding Proteins; D012826:Silicone Elastomers; D015534:Trans-Activators; C487789:mecA protein, Staphylococcus aureus; C074002:nuc protein, staphylococcus; C119204:streptococcal protective antigen; D008836:Micrococcal Nuclease