Table 3

Molecular characteristics of 200 selected extended-spectrum-β-lactamase-producing Escherichia coli isolates (collected in 2000 to 2009) in relation to ST131 and blaCTX-M-15 status

Trait categorya,bSpecific traitaNo. (%) of isolatesP valuec
ST131 M15 (group 1; n = 50)ST131 M15+ (group 2; n = 50)ST131+ M15 (group 3; n = 50)ST131+ M15+ (group 4; n = 50)Group 1 vs 2Group 3 vs 4Group 1 vs 3Group 2 vs 4
Phy. groupGroup A10 (20)28 (56)0 (0)0 (0)<0.001<0.001<0.001
Group B17 (14)1 (2)0 (0)0 (0)0.01
Group B25 (10)0 (0)50 (100)50 (100)<0.001<0.001
Group D28 (56)21 (42)0 (0)0 (0)<0.001<0.001
AdhesinsF10 papA4 (8)5 (10)40 (80)50 (100)0.001<0.001<0.001
afa/draBC3 (6)2 (4)2 (4)13 (26)0.030.004
iha8 (16)3 (6)39 (78)48 (96)0.02<0.001<0.001
fimH42 (84)30 (60)50 (100)50 (100)0.010.006<0.001
hra10 (20)6 (12)1 (2)4 (8)0.008
Toxinssat6 (12)3 (6)39 (78)48 (96)0.02<0.001<0.001
vat6 (12)0 (0)1 (2)0 (0)0.03
astA9 (18)5 (10)0 (0)0 (0)0.03
SiderophoresfyuA30 (60)31 (62)49 (98)50 (100)<0.001<0.001
iutA21 (42)39 (78)43 (86)49 (98)<0.001<0.001<0.001
CapsulekpsM II18 (36)11 (22)35 (70)45 (90)0.020.001<0.001
K23 (6)4 (8)5 (10)17 (34)0.0070.003
K53 (6)0 (0)20 (40)18 (36)<0.001<0.001
kpsMT III3 (6)9 (18)0 (0)0 (0)0.003
Miscellaneoususp7 (14)1 (2)49 (98)50 (100)<0.001<0.001
ompT15 (30)7 (14)48 (96)50 (100)<0.001<0.001
traT34 (68)42 (84)44 (88)46 (92)0.03
malX17 (34)20 (40)48 (96)50 (100)<0.001<0.001
ExPECn.a.d15 (30)7 (14)33 (66)47 (94)0.0010.001<0.001
PFGE statuse≥2 per type9 (19)f22 (44)27 (54)41 (82)0.0090.005<0.001<0.001
≥5 per type0 (0)0 (0)18 (36)33 (66)<0.001<0.001
  • a Traits shown are those that yielded P < 0.05 in an initial four-way comparison (not shown) plus at least one pairwise comparison (as shown). These included afa/draBC (Dr-binding adhesins), astA (enteroaggregative E. coli heat-stable toxin), the F10 papA allele (P fimbria structural subunit variant), fimH (type 1 fimbria adhesin), fyuA (yersiniabactin system), hra (heat-resistant agglutinin), iha (adhesin siderophore), iutA (aerobactin system), K2 (group 2 capsule variant), K5 (group 2 capsule variant), kpsMII (group 2 capsule), kpsMTIII (group 3 capsule), malX (fitness island marker), ompT (outer membrane protease), sat (secreted autotransporter toxin), usp (uropathogenic specific protein), and vat (vacuolating toxin). Traits detected in ≥1 isolate but without significant by-group prevalence differences (definition: overall prevalence) included afaE8 (afimbrial adhesin: 1.5%), bmaE (M fimbriae: 1.5%), cdtB (cytolethal distending toxin B: 0.5%), clbB and clbN (polyketide synthesis: 1% and 2%), clpG (mannose-resistant adhesin: 0.5%), cnf1 (cytotoxic necrotizing factor: 2%), cvaC (microcin V: 1%), H7 fliC allele (flagellin: 0.5%), hlyD (alpha hemolysin: 3.5%), hlyF (hemolysin variant: 4%), ibeA (invasion of brain endothelium: 2%), ireA (siderophore receptor: 1.5%), iroN (salmochelin receptor: 3%), iss (increased serum survival: 3%), K1 (capsule variant: 3%), papAH (P fimbria major subunit: 4.5%), papC (P fimbria assembly: 7.0%), papEFG (P fimbria tip pilins: 5.5%), papG alleles II and III (P adhesin variants: 4.5% and 1%), pic (autotransporter protease: 0.5%), rfc (O4 lipopolysaccharide synthesis: 1%), traT (serum resistance associated: 82.5%), and tsh (temperature-sensitive hemagglutinin: 2%). Traits sought but not detected included F17 (mannose-resistant adhesin), focG (F1C adhesin), gafD (G fimbriae), K15 (capsule variant), papG allele I (P adhesin variant), pic (protein associated with intestinal colonization), sfa/foc (S and F1C fimbriae), and sfaS (S fimbria adhesin).

  • b ExPEC, extraintestinal pathogenic E. coli; PFGE, pulsed-field gel electrophoresis; Phy., phylogenetic. ExPEC was defined as the presence of ≥2 of papA and/or papC and of sfa/foc, afa/dra, kpsMII, and iutA.

  • c P values (by Fisher's exact test, two-tailed) are shown where P < 0.05.

  • d n.a., not applicable.

  • e The data correspond to isolates belonging to pulsotype groups consisting of ≥2 isolates or ≥5 isolates each.

  • f The denominator was 48 (rather than 50), since 2 isolates were refractory to XbaI PFGE analysis.