Bacterial Virulence Characteristics of Escherichia coli Isolates from First-Time Urinary Tract Infection

Foxman, Betsy; Zhang, Lixin; Palin, Karen; Tallman, Patricia; Marrs, Carl F.

doi:10.1093/infdis/171.6.1514

Cited by 105 publications

(102 citation statements)

References 43 publications

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“…Dot blot hybridization. Membranes dotted with single-stranded genomic DNA obtained from crude lysates of each Haemophilus strain were made by using a modification of the method of Foxman et al (13,14). The bacteria were grown overnight on chocolate agar and were suspended in 4 ml of PBS to an optical density of 1.0.…”

Section: Methodsmentioning

confidence: 99%

Relationships of Nontypeable Haemophilus influenzae Strains to Hemolytic and Nonhemolytic Haemophilus haemolyticus Strains

et al. 2008

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Haemophilus influenzae is both a human respiratory pathogen and pharyngeal commensal, while H. haemolyticus, the closest phylogenetic relative of H. influenzae, is arguably a strict pharyngeal commensal. A hemolytic phenotype has historically differentiated H. haemolyticus from H. influenzae, but the recent recognition of significant nonhemolytic H. haemolyticus colonization has decreased this trait's resolvability. Given this and the potential of recombination between the species, we examined the distribution of microbiologic and molecular traits between collections of H. influenzae and H. haemolyticus strains separated within a dendrogram obtained by multilocus sequence analysis (MLSA). All strains hybridizing with a probe to iga, a gene encoding an immunoglobulin A protease of H. influenzae, clustered apart from strains that did not hybridize with the probe. Other traits also segregated significantly along this division, suggesting a separation of the species. Of note, the LOS genes licA, lic2A, and lgtC of H. influenzae were approximately 2, 6, and 54 times, respectively, more prevalent in H. influenzae than in H. haemolyticus. In contrast to species separation, interspecies recombination was evidenced by the inability of single gene sequences to phylogenetically separate the species and by the "fuzzy" distribution of some species-specific traits across the species dividing line. Together, these data support the historically accurate and pragmatic division of these species while recognizing their potential for recombination. Future comparative genomic studies identifying common and distinctive genes could be useful in evaluating their role in the commensal or virulent growth, respectively, of H. influenzae.Haemophilus influenzae is one of eight Haemophilus species that reside as commensal organisms in the pharyngeal cavity of humans. These other commensal Haemophilus species include H. parainfluenzae, H. haemolyticus, H. parahaemolyticus, H. paraphrohaemolyticus, H. segnis, H. aphrophilus, and H. paraphrophilus. H. influenzae is by far the most pathogenic member of the genus in humans. Strains possessing a type b capsule are often associated with invasive diseases, such as meningitis, sepsis, and pneumonia; and strains lacking a capsule (referred to as nontypeable [NT]) are associated with localized mucosal diseases, such as otitis media, sinusitis, and bronchitis. Other haemophili are considered to be rarely associated with disease, and H. haemolyticus has never been implicated as an infectious disease agent (1).In contrast to other haemophili, H. haemolyticus and H. influenzae both depend on X (hemin) and V (NAD) growth factors, both lack the ability to ferment sucrose, both share similar GϩC contents, and both are nearly indistinguishable by their colony and cellular morphologies (25). Initial phylogenetic studies performed by using DNA-DNA hybridization revealed that H. haemolyticus associated with H. influenzae in a cluster of the family Pasteurellaceae termed Haemophilus sensu stricto (6,41,47), and t...

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Section: Methodsmentioning

confidence: 99%

Relationships of Nontypeable Haemophilus influenzae Strains to Hemolytic and Nonhemolytic Haemophilus haemolyticus Strains

et al. 2008

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“…Particularly in non-hospitalized patients, more than 80 % of nonobstructive UTIs are caused by uropathogenic Escherichia coli strains. Different virulence factors have been identified as contributing to their pathogenicity, such as the secreted haemolysin, and specific capsular as well as O-serotypes, for example (Foxman et al, 1995;Ikameimo et al, 1993;Korhonen et al, 1985). The expression of specific adhesins which enable bacteria to attach to and to successfully colonize host tissues in the urinary tract is of particular importance (Wullt et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

The Pix pilus adhesin of the uropathogenic Escherichia coli strain X2194 (O2 : K− : H6) is related to Pap pili but exhibits a truncated regulatory region

et al. 2003

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Adhesins provide a major advantage for uropathogenic Escherichia coli in establishing urinary tract infections (UTIs). A novel gene cluster responsible for the expression of a filamentous adhesin of the pyelonephritogenic E. coli strain X2194 has been identified, molecularly cloned, and characterized. The ‘pix operon’ contains eight open reading frames which exhibit significant sequence homology to corresponding genes in the pap operon encoding P pili, the prevalent E. coli adhesins in non-obstructive acute pyelonephritis in humans. Although a pixB gene corresponding to the PapB regulator was identified, a papI homologue could not be found in the pix operon. Instead, a fragment of the R6 gene of the highly uropathogenic E. coli strain CFT073 was identified upstream of pixB. The R6 gene is located in a pathogenicity island containing several pilus-encoding sequences and shows homology to a transposase of Chelatobacter heintzii. In a pixA–lacZ fusion system it was demonstrated that the expression of Pix pili is regulated at the transcriptional level by the R6 gene sequence. A significantly reduced transcription was observed by deleting this fragment and by lowering the growth temperature from 37 to 26 °C. In contrast to other filamentous adhesin systems, Pix pili are mainly expressed in the steady state growth phase and were not repressed by the addition of glucose.

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“…Although controversies existed for several years, recent investigations have unequivocally documented the importance of type 1 fimbriae as a major urovirulence factor. For instance, of the nine most common E. coli virulence factors, the genes for type 1 fimbriae emerged as the only trait common in all 203 UTI isolates examined (8). In addition, 26% of the 203 strains were positive only for type 1 fimbrial genes and were negative for the eight other urovirulence factors tested, including P, S, and Dr fimbriae.…”

mentioning

confidence: 97%

Tamm-Horsfall Protein Binds to Type 1 Fimbriated Escherichia coli and Prevents E. coli from Binding to Uroplakin Ia and Ib Receptors

Pak

Pu²,

Zhang³

et al. 2001

Journal of Biological Chemistry

274

201

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The adherence of uropathogenic Escherichia coli to the urothelial surface, a critical first step in the pathogenesis of urinary tract infection (UTI), is controlled by three key elements: E. coli adhesins, host receptors, and host defense mechanisms. Although much has been learned about E. coli adhesins and their urothelial receptors, little is known about the role of host defense in the adherence process. Here we show that Tamm-Horsfall protein (THP) is the principal urinary protein that binds specifically to type 1 fimbriated E. coli, the main cause of UTI. The binding was highly specific and saturable and could be inhibited by D-mannose and abolished by endoglycosidase H treatment of THP, suggesting that the binding is mediated by the high-mannose moieties of THP. It is species-conserved, occurring in both human and mouse THPs. In addition, the binding to THP was much greater with an E. coli strain bearing a phenotypic variant of the type 1 fimbrial FimH adhesin characteristic of those prevalent in UTI isolates compared with the one prevalent in isolates from the large intestine of healthy individuals. Finally, a physiological concentration of THP completely abolished the binding of type 1 fimbriated E. coli to uroplakins Ia and Ib, two putative urothelial receptors for type 1 fimbriae. These results establish, on a functional level, that THP contains conserved high-mannose moieties capable of specific interaction with type 1 fimbriae and strongly suggest that this major urinary glycoprotein is a key urinary anti-adherence factor serving to prevent type 1 fimbriated E. coli from binding to the urothelial receptors.The adhesion of Escherichia coli, the most common cause of urinary tract infection (UTI), 1 to urothelial cells is a crucially important first step in UTI pathogenesis (1-5). This adhesion process frequently requires filamentous surface appendages of uropathogenic E. coli that are called fimbriae, or pili. Epidemiological studies have shown that Ͼ90% of all E. coli isolates from UTI patients elaborate type 1 fimbriae (also named mannose-sensitive fimbriae) (4, 6, 7). Although controversies existed for several years, recent investigations have unequivocally documented the importance of type 1 fimbriae as a major urovirulence factor. For instance, of the nine most common E. coli virulence factors, the genes for type 1 fimbriae emerged as the only trait common in all 203 UTI isolates examined (8). In addition, 26% of the 203 strains were positive only for type 1 fimbrial genes and were negative for the eight other urovirulence factors tested, including P, S, and Dr fimbriae. In experimental mouse models, type 1 fimbriae were shown to be indispensable for bladder colonization and infection (9). Conversely, systemic immunization of mice with the FimH tip adhesin of type 1 fimbriae reduced bladder colonization of E. coli by 99% even in neutropenic mice, suggesting that blocking type 1 fimbriae could completely abolish E. coli adhesion (10). Further evidence supporting an important role of type 1 fimbriae ...

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Bacterial Virulence Characteristics of Escherichia coli Isolates from First-Time Urinary Tract Infection

Cited by 105 publications

References 43 publications

Relationships of Nontypeable Haemophilus influenzae Strains to Hemolytic and Nonhemolytic Haemophilus haemolyticus Strains

Relationships of Nontypeable Haemophilus influenzae Strains to Hemolytic and Nonhemolytic Haemophilus haemolyticus Strains

The Pix pilus adhesin of the uropathogenic Escherichia coli strain X2194 (O2 : K− : H6) is related to Pap pili but exhibits a truncated regulatory region

Tamm-Horsfall Protein Binds to Type 1 Fimbriated Escherichia coli and Prevents E. coli from Binding to Uroplakin Ia and Ib Receptors

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