title: Phase variation of biofilm formation in Staphylococcus aureus by IS 256 insertion and its impact on the capacity adhering to polyurethane surface.
abstract: While ica gene of Staphylococcus epidermidis is known to undergo phase variation by insertion of IS256, the phenomenon in Staphylococcus aureus has not been evaluated. Six biofilm-positive strains were tested for the presence of biofilm-negative phase-variant strains by Congo red agar test. For potential phase-variant strains, pulsed-field gel electrophoresis was done to exclude the possibility of contamination. To investigate the mechanism of the biofilm-negative phase variation, PCR for each ica genes were done. Changes of ica genes detected by PCR were confirmed by southern hybridization, and their nucleotides were analyzed by DNA sequencing. Influence of ica genes and biofilm formation on capacity for adherence to biomedical material was evaluated by comparing the ability of adhering to polyurethane surface among a biofilm-negative phase-variant strain and its parent strain. A biofilm-negative phase-variant S. aureus strain was detected from 6 strains tested. icaC gene of the phase-variant strain was found to be inactivated by insertion of additional gene segment, IS256. The biofilm-negative phase-variant strain showed lower adhering capacity to polyurethane than its parent strain. This study shows that phase variation of ica gene occurs in S. aureus by insertion of IS256 also, and this biofilm-negative phase variation reduces adhering capacity of the bacteria.
authors.affiliation: Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul Korea. smkimkor@smc.samsung.co.kr
authors.forename: Sungmin
authors.initials: S
authors.lastname: Kiem
authors.forename: Won Sup
authors.initials: WS
authors.lastname: Oh
authors.forename: Kyong Ran
authors.initials: KR
authors.lastname: Peck
authors.forename: Nam Yong
authors.initials: NY
authors.lastname: Lee
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Song
authors.forename: Eung Soo
authors.initials: ES
authors.lastname: Hwang
authors.forename: Eui-Chong
authors.initials: EC
authors.lastname: Kim
authors.forename: Chang Yong
authors.initials: CY
authors.lastname: Cha
authors.forename: Kang-Won
authors.initials: KW
authors.lastname: Choe
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D004866:Equipment Contamination / Q000517:prevention & control; D016254:Mutagenesis, Insertional / Q000379:methods; D016297:Mutagenesis, Site-Directed / Q000235:genetics; D044367:Phase Transition; D011135:Polysaccharides, Bacterial / Q000235:genetics / Q000378:metabolism*; D011140:Polyurethanes; D013045:Species Specificity; D013211:Staphylococcus aureus / Q000166:cytology / Q000502:physiology*; D013329:Structure-Activity Relationship
chemical_list: D015815:Cell Adhesion Molecules; D011135:Polysaccharides, Bacterial; D011140:Polyurethanes; C113579:polysaccharide intercellular adhesin