TABLE 1.

Prevalence of multicellular pattern formation (rdar morphotype) in the salmonellae (Salmonella reference collection C [10])

Salmonella subgroup and strain(s)aNo. of strains testedNo. of isolates with the following phenotypeb:
Pattern (rdar)Incomplete patternNo patternCalcofluor bindingc
I
    SARC96 1-111190210
        SARC16 110
        SARC16 210
II
    SARC96 12-332218d 2219
        SARC16 311
        SARC16 410
IIIa
    SARC16 510
    SARC16 610
    SARC96 3510
    SARC96 3710
IIIb
    SARC96 38-4254015
        SARC16 711
        SARC16 810
IV
    SARC96 43-7028242224
        SARC16 910
        SARC16 101±
V
    SARC96 71-831310d 0310
        SARC16 111±
        SARC16 1210
VI
    SARC96 84-9298d 019
        SARC16 1311
        SARC16 1410
Subgroup IVe
    SARC96 93-9643013
        SARC16 151d 1
        SARC16 1610
Totals (%)
    SARC969676 (79)4 (4)16 (17)80 (83)
    Without SARC168072 (90)3 (4)5 (6)74 (93)
    SARC16164 (25)1 (6)11 (69)6 (38)
  • a SARC16 isolates represent no. 2, 9, 12, 20, 34, 36, 41, 42, 47, 59, 73, 76, 89, 91, 93, and 94 within SARC96 and are referred to as Sarc1 to -16 in the text. SARC96 no. 35 and 37 are referred to as Sarc35 and Sarc37 in the text. Group V has been designated S. bongori; all other groups are part of S. enterica.

  • b Colony morphology and associated phenotypes were recorded after growth on T agar at 28°C for up to 14 days. Pattern (rdar), colonies had complete surface patterns and could be lifted intact from the agar surface; incomplete pattern, colonies could not be lifted intact from the agar surface; no pattern, colonies were nonaggregative and smooth.

  • c Fluorescence of colonies grown on T agar supplemented with 200 μg/ml calcofluor was observed under a 366-nm UV light source; ±, strains with fluorescence intermediate between those of the ATCC 14028 (positive control) and ΔbcsA (negative control) strains.

  • d SARC96 15, 74, 86, and 93 also formed rdar colonies at 37°C.

  • e These four strains were originally designated a separate subgroup (VII) (10) related to subgroup IV, but this classification has not been widely adopted (11). Therefore, the four isolates are considered members of S. enterica subgroup IV (S. enterica subsp. houtenae).