TABLE 1.
Characteristics of the natural mutator E. coli isolates and their derivative strains
| Strain | Origin | Rifra | mut genotype | Phylogenetic groupb | Presence (+) or absence (−) of extraintestinal virulence determinants:
|
Lethality in micec (%) | Virulence phenotyped | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| K1 antigen | sfa/foc | pap | afa | hly | cnf | aer | ibe10 | Total no. | |||||||
| TIM28 | Pus | 5.9 × 10−6 | mutL mutant | A | − | − | − | − | − | − | − | − | 0 | 0/20 (0) | Typical |
| IAI77 | UTIe | 2.62 × 10−7 | NDf | B2 | − | + | + | − | + | + | − | − | 4 | 26/50 (52) | Atypical |
| SA2077 | UTI | 5 × 10−7 | mutL mutant | A | − | − | − | + | − | − | − | − | 1 | 11/20 (55) | Atypical |
| ECOR 48 | UTI | 8.8 × 10−7 | mutS mutant | D | + | − | + | − | + | + | − | − | 4 | 3/20 (15) | Atypical |
| IAI68 | UTI | 5 × 10−7 | ND | B2 | − | + | + | − | − | − | + | − | 3 | 26/50 (52) | Atypical |
| SA1902 | UTI | 3.25 × 10−6 | mutS mutant | B2 | + | − | − | − | − | − | + | + | 3 | 1/20 (5) | Atypical |
| M13 | Feces | 6.6 × 10−7 | mutS mutant | B1 | − | − | − | − | − | − | − | − | 0 | 5/20 (25) | Atypical |
| M13/pBR322 | This study | 9 × 10−7 | mutS mutant | 22/52 (42) | |||||||||||
| M13/pBA40 | This study | 3.4 × 10−8 | mutS+ | 27/52 (52) | |||||||||||
| SA1923 | UTI | 4.7 × 10−6 | mutS mutant | D | − | + | + | − | + | + | − | + | 5 | 0/20 (0) | Atypical |
| SA1923/pBR322 | This study | 1.57 × 10−6 | mutS mutant | 0/10 (0) | |||||||||||
| SA1923/pBA40 | This study | 2.73 × 10−8 | mutS+ | 0/10 (0) | |||||||||||
a
Frequency of mutations to rifampin resistance.
b
Phylogenetic groups are indicated as given in Herzer et al. (11).
c
Lethality in mice is indicated as the number of mice killed/number of inoculated mice and as the percentage of inoculated mice that died.
d
Atypical virulence phenotype is defined as strains with no to one virulence determinant that kill mice or as strains with three to five virulence determinants that are avirulent or kill mice at an intermediate level.
e
UTI, urinary tract infection.
f
ND, not determined.