TABLE 1.

Hemagglutination and PIA production of transductants with transposon insertions of mutants M10 and M11 in different wild-type strains

Strain	(OD570)a	PIAb (reciprocal titer)	Hemagglutinationc (reciprocal titer)
1457	2.469	1024	128
1457-M10	0.044	0	0
1457-M11	0.045	0	0
9142	1.836	512	64
9142-M10	0.014	0	0
9142-M11	0.020	0	0
8400	2.080	1024	64
8400-M10	0.056	0	0
8400-M11	0.054	0	0
SE-5	2.224	1024	128
RP62A	1.798	1024	256

^aStrains were grown in TSB in 96-well tissue culture plates, the plates were washed with phosphate-buffered saline, cells were fixed with Bouin’s fixative, and adherent bacterial biofilms were stained with gentian violet. Biofilm-producing strains were arbitrarily assigned to have a mean OD₅₇₀ greater than 0.1. 

^bPIA expression was determined in extracts of bacteria grown in TSB by coagglutination. A coagglutination reagent specific for PIA was prepared by sensitizing S. aureus Cowan I with PIA-specific absorbed antiserum. 

^cHemagglutination was assessed as described in Materials and Methods.