The Role of Pili and Capsule in the Pathogenesis of Neonatal Infection with Escherichia coli Kl

Guerina, Nicholas G.; Keßler, Tobias; Guerina, V. J.; Neutra, Marian R.; Clegg, Herbert W.; Langermann, Solomon; Scannapieco, Frank A.; Goldmann, Donald A.

doi:10.1093/infdis/148.3.395

Cited by 83 publications

(64 citation statements)

References 29 publications

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“…Various reports have either supported or questioned the importance of type 1 fimbriae, so the topic remains controversial (1,8,19,25,26,31,33,34,42,50). Nevertheless, the virtual ubiquity of type 1 fimbriae indicates that these fimbriae must serve an essential purpose.…”

Section: Resultsmentioning

confidence: 99%

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FimH family of type 1 fimbrial adhesins: functional heterogeneity due to minor sequence variations among fimH genes

et al. 1994

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We recently reported that the type 1-fimbriated Escherichia coli strains CSH-50 and HB101(pPKIA), both K-12 derivatives, have different patterns of adhesion to yeast mannan, human plasma fibronectin, and fibronectin derivatives, suggesting functional heterogeneity of type 1 fimbriae. In this report, we provide evidence that this functional heterogeneity is due to variations in the fimH genes. We also investigated functional heterogeneity among clinical isolates and whether variation infimH genes accounts for differences in receptor specificity. Twelve isolates obtained from human urine were tested for their ability to adhere to mannan, fibronectin, periodate-treated fibronectin, and a synthetic peptide copying the 30 amino-terminal residues of fibronectin. CSH-50 and HB101(pPKLA) were tested for comparison. Selected isolates were also tested for adhesion to purified fragments spanning the entire fibronectin molecule. Three distinct functional classes, designated M, MF, and MFP, were observed. The fimH genes were amplified by PCR from chromosomal DNA obtained from representative Strains and expressed in a Afim strain (AAEC191A) transformed with a recombinant plasmid containing the entire fim gene cluster but with a translational stop-linker inserted into the fimH gene (pPKL114). Cloned fimH genes conferred on AAEC191A(pPKL114) receptor specificities mimicking those of the parent strains from which the fimH genes were obtained, demonstrating that the FimH subunits are responsible for the functional heterogeneity. RepresentativefimH genes were sequenced, and the deduced amino acid sequences were compared with the previously published FimH sequence. Allelic variants exhibiting >98% homology and encoding proteins differing by as little as a single amino acid substitution confer distinct adhesive phenotypes. This unexpected adhesive diversity within the FimH family broadens the scope of potential receptors for enterobacterial adhesion and may lead to a fundamental change in our understanding of the role(s) that type 1 fimbriae may play in enterobacterial ecology or pathogenesis.

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Section: Resultsmentioning

confidence: 99%

“…The FimA subunit is variable, but FimH is highly conserved antigenically and genetically among enterobacteria (4). Interactions between type 1 fimbriae and D-mannose-containing receptors have been shown in a number of studies to play a key role in the infectious process, but this topic remains somewhat controversial (1,3,8,19,25,26,31,33,44,50).…”

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confidence: 99%

FimH family of type 1 fimbrial adhesins: functional heterogeneity due to minor sequence variations among fimH genes

et al. 1994

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“…This evidence suggests that type 1 fimbriae may play a role in renal scarring by stimulating phagocyte-induced renal injury. Type 1 fimbriae contribute to oropharyngeal but not ileal colonization in rats (33,170). Active or passive antifimbrial immunization protects rats from UTI (493) by blocking epithelial cell adherence (495 (14).…”

Section: Animal Modelsmentioning

confidence: 99%

Virulence factors in Escherichia coli urinary tract infection

1991

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Uropathogenic strains of Escherichia coli are characterized by the expression of distinctive bacterial properties, products, or structures referred to as virulence factors because they help the organism overcome host defenses and colonize or invade the urinary tract. Virulence factors of recognized importance in the pathogenesis of urinary tract infection (UTI) include adhesins (P fimbriae, certain other mannose-resistant adhesins, and type 1 fimbriae), the aerobactin system, hemolysin, K capsule, and resistance to serum killing. This review summarizes the virtual explosion of information regarding the epidemiology, biochemistry, mechanisms of action, and genetic basis of these urovirulence factors that has occurred in the past decade and identifies areas in need of further study. Virulence factor expression is more common among certain genetically related groups of E. coli which constitute virulent clones within the larger E. coli population. In general, the more virulence factors a strain expresses, the more severe an infection it is able to cause. Certain virulence factors specifically favor the development of pyelonephritis, others favor cystitis, and others favor asymptomatic bacteriuria. The currently defined virulence factors clearly contribute to the virulence of wild-type strains but are usually insufficient in themselves to transform an avirulent organism into a pathogen, demonstrating that other as-yet-undefined virulence properties await discovery. Virulence factor testing is a useful epidemiological and research tool but as yet has no defined clinical role. Immunological and biochemical anti-virulence factor interventions are effective in animal models of UTI and hold promise for the prevention of UTI in humans.

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“…The structures apparently play no role in intestinal colonization (7,18,51). However, recent studies have indicated that they may help facilitate colonization of the lower urinary tract (1,21,26,27,31,58) and promote colonization (7), communicability (8), and clearance of E. coli from other extraintestinal sites (46).…”

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Lesions in two Escherichia coli type 1 pilus genes alter pilus number and length without affecting receptor binding

Russell

Orndorff

1992

J Bacteriol

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We describe the characterization of two genes, fimF and fimG (also called pilD), that encode two minor components of type 1 pili in Escherichia coli. Defined, in-frame deletion mutations were generated in vitro in each of these two genes. A double mutation that had deletions identical to both single lesions was also constructed. Examination of minicell transcription and translation products of parental and mutant plasmids revealed that, as predicted from the nucleotide sequence and previous reports, the fimF gene product was a protein of ca. 16 kDa and that the fimG gene product was a protein of ca. 14 kDa. Each of the constructions was introduced, via homologous recombination, into the E. coli chromosome. All three of the resulting mutants produced type 1 pili and exhibited hemagglutination of guinea pig erythrocytes. The latter property was also exhibited by partially purified pili isolated from each of the mutants. Electron microscopic examination revealed that the fimF mutant had markedly reduced numbers of pili per cell, whereas the fimG mutant had very long pili. The double mutant displayed the characteristics of both single mutants. However, pili in the double mutant were even longer than those seen in the fimG mutant, and the numbers of pili were even fewer than those displayed by the fimF mutant. All three mutants could be complemented in trans with a single-copy-number plasmid bearing the appropriate parental gene or genes to give near-normal parental piliation. On the basis of the phenotypes exhibited by the single and double mutants, we believe that the fimF gene product may aid in initiating pilus assembly and that the fimG product may act as an inhibitor of pilus polymerization. In contrast to previous studies, we found that neither gene product was required for type 1 pilus receptor binding.

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The Role of Pili and Capsule in the Pathogenesis of Neonatal Infection with Escherichia coli Kl

Cited by 83 publications

References 29 publications

FimH family of type 1 fimbrial adhesins: functional heterogeneity due to minor sequence variations among fimH genes

FimH family of type 1 fimbrial adhesins: functional heterogeneity due to minor sequence variations among fimH genes

Virulence factors in Escherichia coli urinary tract infection

Lesions in two Escherichia coli type 1 pilus genes alter pilus number and length without affecting receptor binding

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