@article{oai:nagasaki-u.repo.nii.ac.jp:00013771,
 author = {Tamai, Takashi and Tsurumoto, Toshiyuki and Kajiyama, Shiro and Adachi, Shinji and Sakimura, Toshiyuki and Shindo, Hiroyuki},
 issue = {4},
 journal = {Japanese Journal of Infectious Diseases},
 month = {},
 note = {Staphylococcus epidermidis is a cause of orthopedic device-related infection, and to treat such infection, biofilms should be controlled. Polysaccharide intercellular adhesin (PIA) is associated with the biofilm-forming ability of staphylococcal strains. PIA in biofilm-positive staphylococcal strains can be detected by the Congo red agar (CRA) method. In this study, we used the CRA method to examine the effects of subminimal inhibitory concentrations (sub-MICs) of 11 antibacterial agents on PIA production by S. epidermidis. We found that the PIA-negative variants were selected only by sub- MICs of gentamicin (GM). This PIA-negative phenotype was maintained over several generations in the absence of GM. Such selection occurred in six of eight clinical isolates, as well as in the biofilm-positive control strain. No such selection occurred with aminoglycoside antibiotics except for GM. Most of the PIA-negative variants that were selected by GM showed a markedly lower biofilm-forming ability on stainless steel washers than their untreated parent strains. In conclusion, variants with lower biofilmforming ability may be selected by a sub-MIC of GM. Investigation of the reason why variants with reduced biofilm-forming ability can be selected in the presence of sub-MICs of GM may contribute to strategies against biofilm-related infections., Japanese Journal of Infectious Diseases, 64(4), pp.304-308; 2011},
 pages = {304--308},
 title = {Biofilm deficiency in polysaccharide intercellular adhesin-negative variants of staphylococcus epidermidis selected by subminimal inhibitory concentrations of gentamicin},
 volume = {64},
 year = {2011}
}