Previous Article | Next Article 
Infection and Immunity, June 2003, p. 3619-3622, Vol. 71, No. 6
0019-9567/03/$08.00+0 DOI: 10.1128/IAI.71.6.3619-3622.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.
The FimH A27V Mutation Is Pathoadaptive for Urovirulence in Escherichia coli B2 Phylogenetic Group Isolates
Florence Hommais,1 Stéphanie Gouriou,2 Christine Amorin,1 Hung Bui,3 Mohamed Chérif Rahimy,4 Bertrand Picard,2 and Erick Denamur1*
INSERM U458, Hôpital Robert Debré,1
Centre d'Etude du Polymorphisme Humain, Hôpital Saint Louis, Paris,3
Laboratoire de Microbiologie, Hôpital Morvan, Brest, France,2
Faculté des Sciences de la Santé, Cotonou, République du Bénin4
Received 21 October 2002/
Returned for modification 23 December 2002/
Accepted 13 March 2003

ABSTRACT
Correlations between FimH mutations and virulence were established
by studying a collection of human commensal and extraintestinal
pathogenic
Escherichia coli natural isolates. Pathoadaptive
(A27V and, to a lesser extent, A119V) and "commensal-adaptive"
(A202V) mutations were evidenced in B2 phylogenetic group strains.
fimH phylogenetic analysis indicates that these pathoadaptive
mutations occurred several times.

TEXT
One of the mechanisms in bacterial evolution towards virulence
is the allelic variation of existing genes that has been called
pathoadaptive (
19). One of the most studied pathoadaptive mutations
is the allelic variation within the adhesive subunit of type
I fimbriae, FimH, of
Escherichia coli (
15,
16,
18). This bacterium
is a normal inhabitant of the intestinal tract of vertebrates
but can also be responsible for intestinal and extraintestinal
diseases (mainly urinary tract infections [UTI] and septicemia).
Indeed, all
E.
coli isolates are capable of binding to trimannose
receptors, allowing bacteria to bind buccal epithelial cells.
In addition, 70% of UTI isolates bind to both trimannose and
monomannose residues (
17), allowing them to adhere strongly
to uroepithelial cells. This change in tissue tropism is due
to a small number of amino acid changes in FimH, an otherwise
highly conserved molecule (
1,
7,
14,
15). In vitro mutagenesis
and analysis of the FimH sequences of a small number of natural
isolates had allowed the identification of the amino acids responsible
for an increase in binding monomannose residues (
13,
17,
18).
Moreover, previous studies have shown a link between long-term
evolutionary history (strain phylogeny) and virulence in
E.
coli, as extraintestinal
E.
coli pathogens (including UTI strains)
belonged preferentially to one of the four main
E.
coli phylogenetic
groups, i.e., the B2 phylogenetic group (
9,
12). Thus, the simultaneous
action on virulence of both single-mutation effects and the
accumulated divergence in genetic background over millions of
years led us to study more carefully the diversity and evolutionary
history of the
fimH gene from natural strains belonging to the
various
E.
coli phylogenetic groups (
6). We sequenced the
fimH gene from the first postsignal peptide codon to codon 232 in
an epidemiologic collection encompassing both 44 commensal and
69 pathogenic strains. The strains were isolated mainly in France
and in Benin and included two previously published collections
(
11,
12).
fimH amplification was performed by standard PCR from
bacterial lysate using primer fimHF (5'-TGATGGGCTGGTCGGTAAATG-3')
and fimH3R (5'-CGATACCGTGTTATTCGCTGG-3'). PCR products were
directly sequenced on both strands without interim cloning.
In addition, the phylogenetic group (A, B1, D, and B2 [
6]) to
which the strains belong was determined by PCR as described
by Clermont et al. (
2), and the intrinsic extraintestinal virulence
of the strains was tested by inoculating 10 mice per strain
followed by scoring of deaths, as described by Picard et al.
(
12).
The Pearson correlation coefficients between the different FimH amino acid mutations and the characteristics of the strains, i.e., their origin of isolation (normal feces, urine, blood, miscellaneous infections), their phylogenetic groups, and the lethality in mice (0 to 1 mouse, 2 to 8 mice, and 9 to 10 mice killed of 10 mice inoculated), were calculated, and the statistical significance was evaluated by a Fisher test. Among the coding sequence, 33 amino acids were found to be variable, but only 7 of those, which were found variable in more than seven strains, were considered in the statistical analyses (Table 1). Except for A202V, all amino acid changes considered here (A27V, G66S/C, N70S, S78N, A119V, V163A) were previously described as polymorphic and potentially pathoadaptive for E. coli (15). Fifteen different FimH alleles (I to XV) were found in our collection of natural isolates (Table 1). While most amino acid mutations were widespread among the 15 alleles, the V163A mutation was found only in allele V in combination with both N70S and S78N mutations. Moreover, mutations N70S and S78N were almost always found together (0.865; P < 0.0001) and were the most common amino acid mutations. These two mutations are localized within ß-sheet 6 in the three-dimensional structure of FimH (1).
When all strains were considered, significant correlations were
found only between N70S/S78N mutations, the B2 phylogenetic
group (0.467;
P < 0.0001), and lethality in mice (0.316;
P < 0.0009). In addition, a link between virulence in mice
and B2 phylogenetic group was observed in our data (0.529;
P < 0.0001), in accordance with previous works (
8,
12). To
know whether N70S and S78N mutations were correlated with lethality
in mice independently from phylogenetic groups, we looked for
correlations between FimH amino acid mutations, origin, and
virulence in B2 group strains (68 strains, of which 28 are commensal
and 40 are pathogenic). No significant correlation was observed
for the N70S/S78N mutations, indicating that the previously
observed correlation with lethality in mice was due to the B2
specificity of these mutations and not to the pathogenic nature
of the strain.
Among the B2 strains, a highly significant correlation was found between the A27V mutation and UTI strains (0.378; P < 0.002). To a lesser extent, significant correlations were also found between the A119V mutation and UTI strains (0.273; P < 0.03) and between the A202V mutation and strains isolated from feces (0.307; P < 0.016). Because of the small sample size used to calculate these last two coefficients, additional B2 strains should be tested to confirm these data. In addition, a correlation was found between the A27V mutation and virulence in mice (0.330; P < 0.009). This mutation is localized in a loop between ß-sheets 3 and 4 (1), and previous in vitro binding assays had shown a potential role of A27V mutation in the capacity of the strain to bind to monomannose (17) (Table 1). No correlation was found when non-B2 group strains were analyzed (data not shown). Taken together, these data strongly suggest a pathoadaptive role of the A27V mutation in the natural environment.
Having demonstrated that FimH has both mutations that are linked to the global phylogeny of the strains (N70S/S78N) and mutations that are linked to the environment (A27V, A119V, and A202V), we then compared the fimH gene and the strain phylogenies to understand the fimH evolutionary history. The unrooted tree reconstructed from the fimH sequences showed a grouping that is incongruent with the phylogenetic groups to which the strains belong (Fig. 1), an argument for the occurrence of horizontal gene transfers during fimH evolution (3, 5). The mutations separating the monophyletic group of B2 strains supported by a bootstrap value of 88% from the remaining strains, which also encompass some B2 strains (Fig. 1), were determined with MacClade (10). They are not scattered all over the sequence but are clustered between nucleotides 183 and 351 (data not shown), a feature typical of gene transfer (3). It could be assumed that the monophyletic group of B2 strains which possesses the N70S/S78N mutations corresponds to the true B2, whereas the remaining B2 strains have suffered from horizontal gene transfers. In addition, the phylogenetic tree (Fig. 1) indicated that the nucleotide changes corresponding to the A27V and A119V mutations (C80T and C356T, respectively) were each flanked by different sequences (three and two sequences, respectively). Thus, pathoadaptive mutations had arisen several times during the evolution.
This study is the first large-scale analysis of FimH pathoadaptive
mutations from a collection of well-characterized natural isolates.
Altogether, our data indicated that pathoadaptive mutations
are selected for in nature in B2 phylogenetic group strains.
Since B2 strains have numerous extraintestinal virulence determinants,
virulence can be considered a multifactorial trait as previously
suggested (
8), with a probably essential effect of the genetic
background of the strain in the rise of particular mutations
such as pathoadaptive ones. Furthermore, the concept of commensal-adaptive
mutation could be proposed for the A202V mutation, which was
preferentially present in B2 group strains isolated from feces.
It would be interesting to test whether FimH A202V strains adhere
better to gut epithelium. Moreover, one could propose that the
balancing selection for these patho- and commensal-adaptive
mutations could explain the presence of B2 group strains in
normal feces (
4,
21).

ACKNOWLEDGMENTS
This study was partially supported by a grant from the Programme
de Recherche Fondamentale en Microbiologie et Maladies Infectieuses
et Parasitaires (MENRT).
We are grateful to Olivier Pradillon for technical help and to Patricia Escobar-Páramo and Olivier Tenaillon for their comments on the manuscript.

FOOTNOTES
* Corresponding author. Mailing address: INSERM E03 39, IFR 02, Faculté de Médecine Xavier Bichat, 16 rue Henri Huchard, 75018 Paris, France. Phone: 33 (1) 44 85 61 56. Fax: 33 (1) 44 85 61 49. E-mail:
denamur{at}bichat.inserm.fr.

Editor: V. J. DiRita

REFERENCES
1 - Choudhury, D., A. Thompson, V. Stojanoff, S. Langermann, J. Pinkner, S. J. Hultgren, and S. D. Knignt. 1999. X-ray structure of the FimC-FimH chaperone-adhesin complex from uropathogenic Escherichia coli. Science 285:1061-1066.[Abstract/Free Full Text]
2 - Clermont, O., S. Bonacorsi, and E. Bingen. 2000. Rapid and simple determination of the Escherichia coli phylogenetic groups. Appl. Environ. Microbiol. 66:4555-4558.[Abstract/Free Full Text]
3 - Denamur, E., G. Lecointre, P. Darlu, O. Tenaillon, C. Acquaviva, C. Sayada, I. Sunjevaric, R. Rothstein, J. Elion, F. Taddei, M. Radman, and I. Matic. 2000. Evolutionary implications of the frequent horizontal transfer of mismatch repair genes. Cell 103:711-721.[CrossRef][Medline]
4 - Duriez, P., O. Clermont, S. Bonacorsi, E. Bingen, A. Chaventré, J. Elion, B. Picard, and E. Denamur. 2001. Commensal Escherichia coli isolates are phylogenetically distributed among geographically distinct human populations. Microbiology 147:1671-1676.[Abstract/Free Full Text]
5 - Dykhuizen, D. E., and L. Green. 1991. Recombination in Escherichia coli and the definition of biological species. J. Bacteriol. 173:7257-7268.[Abstract/Free Full Text]
6 - Herzer, P. J., S. Inouye, M. Inouye, and T. S. Whittman. 1990. Phylogenetic distribution of branched RNA-linked multicopy single-stranded DNA among natural isolates of Escherichia coli. J. Bacteriol. 172:6175-6181.[Abstract/Free Full Text]
7 - Hung, C. S., J. Bouckaert, D. Hung, J. Pinkner, C. Widberg, A. DeFusco, C. G. Auguste, R. Strouse, S. Langermann, G. Walsman, and S. J. Hultgren. 2002. Structural basis of tropism of Escherichia coli to the bladder during urinary tract infection. Mol. Microbiol. 44:903-915.[CrossRef][Medline]
8 - Johnson, J. R., M. Kuskowski, E. Denamur, J. Elion, and B. Picard. 2000. Clonal origin, virulence factors, and virulence. Infect. Immun. 68:424-425.[Free Full Text]
9 - Johnson, J. R., and A. L. Stell. 2000. Extended virulence genotypes of Escherichia coli strains from patients with urosepsis in relation to phylogeny and host compromise. J. Infect. Dis. 181:261-272.[CrossRef][Medline]
10 - Maddison, D. R., and W. P. Maddison. 2000. MacClade 4: analysis of phylogeny and character evolution, version 4.0. Sinauer Associates, Sunderland, Mass.
11 - Picard, B., P. Duriez, S. Gouriou, I. Matic, E. Denamur, and F. Taddei. 2001. Mutator natural Escherichia coli isolates have an unusual virulence phenotype. Infect. Immun. 69:9-14.[Abstract/Free Full Text]
12 - Picard, B., J. S. Garcia, S. Gouriou, P. Duriez, N. Brahimi, E. Bingen, J. Elion, and E. Denamur. 1999. The link between phylogeny and virulence in Escherichia coli extraintestinal infection. Infect. Immun. 67:546-553.[Abstract/Free Full Text]
13 - Schembri, M. A., E. V. Sokurenko, and P. Klemm. 2000. Functional flexibility of the FimH adhesin: insights from a random mutant library. Infect. Immun. 68:2638-2646.[Abstract/Free Full Text]
14 - Sokurenko, E. V., V. Chesnokova, R. J. Doyle, and D. L. Hasty. 1997. Diversity of the Escherichia coli type 1 fimbrial lectin. J. Biol. Chem. 272:17880-17886.[Abstract/Free Full Text]
15 - Sokurenko, E. V., V. Chesnokova, D. E. Dykhuizen, I. Ofek, X. R. Wu, K. A. Krogfelt, C. Struve, M. A. Schembri, and D. L. Hasty. 1998. Pathogenic adaptation of Escherichia coli by natural variation of FimH adhesin Proc. Natl. Acad. Sci. USA 95:8922-8926.[Abstract/Free Full Text]
16 - Sokurenko, E. V., H. S. Courtney, S. N. Abraham, P. Klemm, and D. L. Hasty. 1992. Functional heterogeneity of type 1 fimbriae of Escherichia coli. Infect. Immun. 60:4709-4719.[Abstract/Free Full Text]
17 - Sokurenko, E. V., H. S. Courtney, J. Maslow, A. Siitonen, and D. L. Hasty. 1995. Quantitative differences in adhesiveness to type 1 fimbriated Escherichia coli due to structural differences in fimH genes. J. Bacteriol. 177:3680-3686.[Abstract/Free Full Text]
18 - Sokurenko, E. V., H. S. Courtney, D. E. Ohman, P. Klemm, and D. L. Hasty. 1994. FimH family of type 1 adhesins: functional heterogeneity due to minor sequence variations among fimH genes. J. Bacteriol. 176:748-755.[Abstract/Free Full Text]
19 - Sokurenko, E. V., D. L. Hasty, and D. E. Dykhuizen. 1999. Pathoadaptive mutations: gene loss and variation in bacterial pathogens. Trends Microbiol. 7:191-195.[CrossRef][Medline]
20 - Swofford, D. 2002. PAUP*: phylogenetic analysis using parsimony (*and other methods), version 4.0. Sinauer Associates, Sunderland, Mass.
21 - Zhang, L., B. Foxman, and C. Marrs. 2002. Both urinary and rectal Escherichia coli isolates are dominated by strains of phylogenetic group B2. J. Clin. Microbiol. 40:3951-3955.[Abstract/Free Full Text]
Infection and Immunity, June 2003, p. 3619-3622, Vol. 71, No. 6
0019-9567/03/$08.00+0 DOI: 10.1128/IAI.71.6.3619-3622.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.
This article has been cited by other articles:
-
Stahlhut, S. G., Tchesnokova, V., Struve, C., Weissman, S. J., Chattopadhyay, S., Yakovenko, O., Aprikian, P., Sokurenko, E. V., Krogfelt, K. A.
(2009). Comparative Structure-Function Analysis of Mannose-Specific FimH Adhesins from Klebsiella pneumoniae and Escherichia coli. J. Bacteriol.
191: 6592-6601
[Abstract]
[Full Text]
-
Stahlhut, S. G., Chattopadhyay, S., Struve, C., Weissman, S. J., Aprikian, P., Libby, S. J., Fang, F. C., Krogfelt, K. A., Sokurenko, E. V.
(2009). Population Variability of the FimH Type 1 Fimbrial Adhesin in Klebsiella pneumoniae. J. Bacteriol.
191: 1941-1950
[Abstract]
[Full Text]
-
Tartof, S. Y., Solberg, O. D., Riley, L. W.
(2007). Genotypic analyses of uropathogenic Escherichia coli based on fimH single nucleotide polymorphisms (SNPs). J Med Microbiol
56: 1363-1369
[Abstract]
[Full Text]
-
Weissman, S. J., Beskhlebnaya, V., Chesnokova, V., Chattopadhyay, S., Stamm, W. E., Hooton, T. M., Sokurenko, E. V.
(2007). Differential Stability and Trade-Off Effects of Pathoadaptive Mutations in the Escherichia coli FimH Adhesin. Infect. Immun.
75: 3548-3555
[Abstract]
[Full Text]
-
Nowrouzian, F. L., Friman, V., Adlerberth, I., Wold, A. E.
(2007). Reduced Phase Switch Capacity and Functional Adhesin Expression of Type 1-Fimbriated Escherichia coli from Immunoglobulin A-Deficient Individuals. Infect. Immun.
75: 932-940
[Abstract]
[Full Text]
-
Brzuszkiewicz, E., Bruggemann, H., Liesegang, H., Emmerth, M., Olschlager, T., Nagy, G., Albermann, K., Wagner, C., Buchrieser, C., Emody, L., Gottschalk, G., Hacker, J., Dobrindt, U.
(2006). How to become a uropathogen: Comparative genomic analysis of extraintestinal pathogenic Escherichia coli strains. Proc. Natl. Acad. Sci. USA
103: 12879-12884
[Abstract]
[Full Text]
-
Simpson, K. W., Dogan, B., Rishniw, M., Goldstein, R. E., Klaessig, S., McDonough, P. L., German, A. J., Yates, R. M., Russell, D. G., Johnson, S. E., Berg, D. E., Harel, J., Bruant, G., McDonough, S. P., Schukken, Y. H.
(2006). Adherent and Invasive Escherichia coli Is Associated with Granulomatous Colitis in Boxer Dogs.. Infect. Immun.
74: 4778-4792
[Abstract]
[Full Text]
-
Nilsson, L. M., Thomas, W. E., Trintchina, E., Vogel, V., Sokurenko, E. V.
(2006). Catch Bond-mediated Adhesion without a Shear Threshold: TRIMANNOSE VERSUS MONOMANNOSE INTERACTIONS WITH THE FimH ADHESIN OF ESCHERICHIA COLI. J. Biol. Chem.
281: 16656-16663
[Abstract]
[Full Text]
-
Sokurenko, E. V., Feldgarden, M., Trintchina, E., Weissman, S. J., Avagyan, S., Chattopadhyay, S., Johnson, J. R., Dykhuizen, D. E.
(2004). Selection Footprint in the FimH Adhesin Shows Pathoadaptive Niche Differentiation in Escherichia coli. Mol Biol Evol
21: 1373-1383
[Abstract]
[Full Text]