Phase variation of biofilm formation in Staphylococcus aureus by IS 256 insertion and its impact on the capacity adhering to polyurethane surface.
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.
Kiem
Sungmin
S
Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul Korea. smkimkor@smc.samsung.co.kr
Oh
Won Sup
WS
Peck
Kyong Ran
KR
Lee
Nam Yong
NY
Lee
Ji-Young
JY
Song
Jae-Hoon
JH
Hwang
Eung Soo
ES
Kim
Eui-Chong
EC
Cha
Chang Yong
CY
Choe
Kang-Won
KW
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
D015815:Cell Adhesion Molecules; D011135:Polysaccharides, Bacterial; D011140:Polyurethanes; C113579:polysaccharide intercellular adhesin