Surface Components of Escherichia coli That Mediate Resistance to the Bactericidal Activities of Serum and Phagocytes

Timmis, Kenneth N.; Boulnois, Graham J.; Bitter‐Suermann, D.; Cabello, Felipe C.

doi:10.1007/978-3-642-70586-1_11

Cited by 65 publications

(65 citation statements)

References 68 publications

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“…1) and Iss levels that we find in this study (Fig. 4, lane 3; note that the amount of protein seen here is produced from a high-copy-number subclone; the level in cells carrying the large wild-type ColV,I-K94 plasmid may be somewhat lower), are roughly 5-to 10-fold lower than levels estimated for TraT proteins (38,59). This finding, as well as the observation that the protective effect of iss is not dosage dependent (4,14), suggests the possibility that Bor/Iss exerts its effect on serum sensitivity through an enzymatic rather than structural role in the outer membrane.…”

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confidence: 42%

“…Serum resistance is a property which could play a significant role in phage and bacterial natural selection in animal hosts. It is also a hallmark of many types of pathogenic microorganisms and is one of the most extensively studied of bacterial virulence factors (7,30,58,59,62,63). An understanding of the functioning of Bor is therefore of interest both in the context of the evolutionary functions of temperate phage accessory genes and with respect to microbial pathogenesis.…”

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confidence: 99%

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bor gene of phage lambda, involved in serum resistance, encodes a widely conserved outer membrane lipoprotein

1995

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bor is one of two recently identified genes of phage which are expressed during lysogeny and whose products display homology to bacterial virulence proteins. bor is closely related to the iss locus of plasmid ColV,I-K94, which promotes bacterial resistance to serum complement killing in vitro and virulence in animals. bor has a similar in vitro effect. We show here that the bor gene product is a lipoprotein located in the Escherichia coli outer membrane. We also find that antigenically related proteins are expressed by lysogens of a number of other lambdoid coliphage, in cells carrying the cloned iss gene, and in several clinical isolates of E. coli. These results demonstrate that bor sequences are widespread and present a starting point for mechanistic analysis of bor-mediated serum resistance.Bacteriophage has long served as a model system for the study of fundamental biological processes, yet even now significant parts of biology remain poorly understood. One area of notable obscurity is the function of the so-called accessory sequences (16) which comprise roughly a third of the genome and are dispensable for growth and viability under laboratory conditions. These sequences contain numerous open reading frames of unknown function, and their retention in the face of presumably long-standing selective pressures suggests that they have functions which may provide consequential selective benefits.We have previously characterized two genes, lom and bor, whose distinctive features offer a novel perspective on the function of these accessory sequences and on the evolutionary significance of lysogeny by temperate phage generally (2). Both lom and bor are dispensable for phage vegetative growth, are expressed in Escherichia coli lysogens, and are related to bacterial virulence proteins. Lom is homologous to three such proteins, Ail, PagC, and Rck, which are involved in invasiveness of Yersinia enterocolitica, survival in macrophage phagosomes, and serum resistance of Salmonella typhimurium, respectively (23,35,46). A fifth member of the family, the Enterobacter cloacae protein OmpX, has not been associated with virulence properties (53, 54). None of these proteins is phage encoded.The phage bor gene is closely related to the iss locus of the conjugative plasmid ColV,I-K94. Sequencing (13) has shown that iss displays a discrete block of 796 bp of DNA homology to covering the region from bp 46186 to 46982 in the sequence (50), which is at the 3Ј end of R Z , at the extreme right end of the genome. On either side of this region, homology to is not detectable. The overall DNA identity between and iss is 81%, excluding gaps. The homologous region includes bor, 230 bp of 5Ј flanking DNA, and 274 bp of 3Ј flanking material which includes the coding region for the last 79 residues of R Z . Thus, iss appears to be a fragment of (or, less likely, vice versa), and it seems probable that the locus originated in a fairly recent recombination event between ColV,I-K94 and or a related phage. The iss open reading frame homologous to ...

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confidence: 42%

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confidence: 99%

bor gene of phage lambda, involved in serum resistance, encodes a widely conserved outer membrane lipoprotein

1995

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“…Among the test organisms selected first was a K1-encapsulated E. coli strain, containing short chain (rough chemotype) LPS ("K1 /r"). This highly BPI-sensitive organism (21 ) because ofthe presence of (K1 ) capsule is likely to be resistant to the cellular and extracellular antibacterial systems in blood (21,27,28) and representative of strains that are prominent in clinical infections (29)(30)(31). We have shown before that ( K 1 ) capsule does not increase bacterial resistance to BPI (21).…”

Section: Resultsmentioning

confidence: 98%

Human bactericidal/permeability-increasing protein and a recombinant NH2-terminal fragment cause killing of serum-resistant gram-negative bacteria in whole blood and inhibit tumor necrosis factor release induced by the bacteria.

Weiss

Elsbach²,

Chen³

et al. 1992

J. Clin. Invest.

214

136

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The bactericidal/ permeability-increasing protein (BPI) ofneutrophils and BPI fragments neutralize the effects of isolated Gram-negative bacterial lipopolysaccharides both in vitro and in vivo. Since endotoxin most commonly enters the host as constituents of invading Gram-negative bacteria, we raised the question: Can BPI and its bioactive fragments also protect against whole bacteria? To determine whether the bactericidal and endotoxin-neutralizing activities of BPI / fragments are expressed when Gram-negative bacteria are introduced to the complex environment of whole blood we examined the effects of added BPI and proteolytically prepared and recombinant NH2-terminal fragments on: (a) the fate of serum-resistant encapsulated Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa that survive the antibacterial actions of whole blood and (b) the ability of these bacteria to trigger cytokine release. Added BPI in nanomolar concentrations killed each ofthree encapsulated strains ofE. coli and in closely parallel fashion inhibited tumor necrosis factor (TNF) release. Holo-BPI and its NH2-terminal fragment were equipotent toward a rough LPS chemotype Kl-encapsulated strain, but the fragment was substantially more potent than holo-BPI toward two encapsulated smooth LPS chemotype strains. TNF release induced by K. pneumoniae and P. aeruginosa was also inhibited by both holo-BPI and fragment but, at the protein concentrations tested, P. aeruginosa was killed only by the fragment and K. pneumoniae was not killed by either protein. The bactericidal action of BPI/fragment toward E. coli is inhibited by C7-depleted serum, but accelerated by normal serum, indicating that BPI, acting in synergy with late complement components, enhances extracellular killing of serum-resistant bacteria. Thus, BPI and an even more potent NH2-terminal fragment may protect against Gram-negative bacteria in the host by blocking bacterial proliferation as well as endotoxin-mediated

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“…However, this inactivation had no effect on K15 capsule expression, serum resistance, and virulence of E. coli strain 536 (Table 3 and It has been amply reported that group 2 capsules are more frequently distributed among uropathogenic isolates than among fecal isolates (26,27,50). This led to the speculation that group 2 capsules contribute to urovirulence according to their ability to impede phagocytosis (13,34,54). The capsule has also been reported to confer resistance to the bactericidal activity of serum (2,13,31,47).…”

Section: Discussionmentioning

confidence: 99%

The Pathogenicity Island-Associated K15 Capsule Determinant Exhibits a Novel Genetic Structure and Correlates with Virulence in Uropathogenic Escherichia coli Strain 536

Schneider

Dobrindt

Brüggemann³

et al. 2004

Infect Immun

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The K15 capsule determinant of uropathogenic Escherichia coli strain 536 (O6:K15:H31) is part of a novel 79.6-kb pathogenicity island (PAI) designated PAI V 536 that is absent from the genome of nonpathogenic E. coli K-12 strain MG1655. PAI V 536 shows typical characteristics of a composite PAI that is associated with the pheV tRNA gene and contains the pix fimbriae determinant as well as genes coding for a putative phosphoglycerate transport system, an autotransporter protein, and hypothetical open reading frames. A gene cluster coding for a putative general secretion pathway system, together with a kps K15 determinant, is localized downstream of a truncated pheV gene (pheV) also present in this chromosomal region. The distribution of genes present on PAI V 536 was studied by PCR in different pathogenic and nonpathogenic E. coli isolates of various sources. Analysis of the 20-kb kps locus revealed a so far unknown genetic organization. Generally, the kps K15 gene cluster resembles that of group 2 and 3 capsules, where two conserved regions (regions 1 and 3) are located up-or downstream of a highly variable serotype-specific region (region 2). Interestingly, recombination of a group 2 and 3 determinant may have been involved in the evolution of the K15 capsule-encoding gene cluster. Expression of the K15 capsule is important for virulence in a murine model of ascending urinary tract infection but not for serum resistance of E. coli strain 536.

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Surface Components of Escherichia coli That Mediate Resistance to the Bactericidal Activities of Serum and Phagocytes

Cited by 65 publications

References 68 publications

bor gene of phage lambda, involved in serum resistance, encodes a widely conserved outer membrane lipoprotein

bor gene of phage lambda, involved in serum resistance, encodes a widely conserved outer membrane lipoprotein

Human bactericidal/permeability-increasing protein and a recombinant NH2-terminal fragment cause killing of serum-resistant gram-negative bacteria in whole blood and inhibit tumor necrosis factor release induced by the bacteria.

The Pathogenicity Island-Associated K15 Capsule Determinant Exhibits a Novel Genetic Structure and Correlates with Virulence in Uropathogenic Escherichia coli Strain 536

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