Table 1.

Bacterial strains and plasmids

Strain or plasmidRelevant characteristicsaOrigin or reference
S. epidermidis220 ica positive, biofilm positiveb; origin of template DNA for PCR amplification of the ica promoter segment (icaprom ); host for chromosomal integration of plasmid pSK2Clinical isolate, catheter-related septicemia (this study)
S. epidermidis 220-1Derivative of S. epidermidis 220 carrying a chromosomally integrated copy of pSK2; Chlr This study
S. aureusRN4220Restriction-negative derivative of S. aureus 8325; cloning host 26
S. epidermidisRP62ABiofilm-positive control strainATCC 32984
S. carnosus TM300Biofilm-negative control strain 21
E. coliMC4100 lacZ negative; cloning host 9
S. epidermidis567 ica positive; biofilm negativeb Clinical isolate, urinary tract infection (this study)
S. epidermidis561 ica positive; biofilm negativeb Clinical isolate, urinary tract infection (this study)
pSK1 E. coli high copy number vector pUC18 (52) carrying the ica promoter segment of S. epidermidis 220; Ampr This study
pKO10Derivative of the pBT1 shuttle vector (8) carrying lacZ fused to the S. aureus alpha-toxin promoter and a temperature-sensitive origin of replication; Ampr Chlr 35
pSK2pBT1 shuttle vector (8) containing the Pica::lacZ fusion and a temperature-sensitive origin of replication; AmprChlr This study
  • a Amp, ampicillin; Chl, chloramphenicol; r, resistant.

  • b Determined by a quantitative adherence assay in tissue culture plates using tryptic soy broth (Difco) as the growth medium.