Adhesins, Serum Resistance and Cytolysins of E. Coli- Genetic Structure and Role in Pathogenicity

1988 ◽  
pp. 221-229
Author(s):  
J. Hacker ◽  
W. Goebel ◽  
H. Hof ◽  
W. Konig ◽  
B. Konig ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Serum Resistance ◽  
E Coli

scholarly journals Role of Virulence Factors in Resistance of Avian Pathogenic Escherichia coli to Serum and in Pathogenicity

2003 ◽  
Vol 71 (1) ◽  
pp. 536-540 ◽  
Author(s):  
Melha Mellata ◽  
Maryvonne Dho-Moulin ◽  
Charles M. Dozois ◽  
Roy Curtiss ◽  
Peter K. Brown ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Bacterial Resistance ◽  
Serum Resistance ◽  
Temperature Sensitive ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
K1 Capsule

ABSTRACT In chickens, colibacillosis is caused by avian pathogenic Escherichia coli (APEC) via respiratory tract infection. Many virulence factors, including type 1 (F1A) and P (F11) fimbriae, curli, aerobactin, K1 capsule, and temperature-sensitive hemagglutinin (Tsh) and plasmid DNA regions have been associated with APEC. A strong correlation between serum resistance and virulence has been demonstrated, but roles of virulence factors in serum resistance have not been well elucidated. By using mutants of APEC strains TK3, MT78, and χ7122, which belong to serogroups O1, O2, and O78, respectively, we investigated the role of virulence factors in resistance to serum and pathogenicity in chickens. Our results showed that serum resistance is one of the pathogenicity mechanisms of APEC strains. Virulence factors that increased bacterial resistance to serum and colonization of internal organs of infected chickens were O78 lipopolysaccharide of E. coli χ7122 and the K1 capsule of E. coli MT78. In contrast, curli, type 1, and P fimbriae did not appear to contribute to serum resistance. We also showed that the iss gene, which was previously demonstrated to increase resistance to serum in certain E. coli strains, is located on plasmid pAPEC-1 of E. coli χ7122 but does not play a major role in resistance to serum for strain χ7122.

scholarly journals Peptidoglycan Association of Murein Lipoprotein Is Required for KpsD-Dependent Group 2 Capsular Polysaccharide Expression and Serum Resistance in a UropathogenicEscherichia coliIsolate

mBio ◽  
2017 ◽  
Vol 8 (3) ◽  
Author(s):  
Jingyu Diao ◽  
Catrien Bouwman ◽  
Donghong Yan ◽  
Jing Kang ◽  
Anand K. Katakam ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Capsular Polysaccharide ◽  
Cell Envelope ◽  
Bloodstream Infections ◽  
Serum Resistance ◽  
E Coli ◽  
Serum Killing ◽  
Group 2

ABSTRACTMurein lipoprotein (Lpp) and peptidoglycan-associated lipoprotein (Pal) are major outer membrane lipoproteins inEscherichia coli. Their roles in cell-envelope integrity have been documented inE. colilaboratory strains, and while Lpp has been linked to serum resistancein vitro, the underlying mechanism has not been established. Here,lppandpalmutants of uropathogenicE. colistrain CFT073 showed reduced survival in a mouse bacteremia model, but only thelppmutant was sensitive to serum killingin vitro. The peptidoglycan-bound Lpp form was specifically required for preventing complement-mediated bacterial lysisin vitroand complement-mediated clearancein vivo. Compared to the wild-type strain, thelppmutant had impaired K2 capsular polysaccharide production and was unable to respond to exposure to serum by elevating capsular polysaccharide amounts. These properties correlated with altered cellular distribution of KpsD, the predicted outer membrane translocon for “group 2” capsular polysaccharides. We identified a novel Lpp-dependent association between functional KpsD and peptidoglycan, highlighting important interplay between cell envelope components required for resistance to complement-mediated lysis in uropathogenicE. coliisolates.IMPORTANCEUropathogenicE. coli(UPEC) isolates represent a significant cause of nosocomial urinary tract and bloodstream infections. Many UPEC isolates are resistant to serum killing. Here, we show that a major cell-envelope lipoprotein (murein lipoprotein) is required for serum resistancein vitroand for complement-mediated bacterial clearancein vivo. This is mediated, in part, through a novel mechanism by which murein lipoprotein affects the proper assembly of a key component of the machinery involved in production of “group 2” capsules. The absence of murein lipoprotein results in impaired production of the capsule layer, a known participant in complement resistance. These results demonstrate an important role for murein lipoprotein in complex interactions between different outer membrane biogenesis pathways and further highlight the importance of lipoprotein assembly and transport in bacterial pathogenesis.

scholarly journals Genetic Structure of the nadA and nadB Antivirulence Loci in Shigella spp.

2007 ◽  
Vol 189 (17) ◽  
pp. 6482-6486 ◽  
Author(s):  
Anne-Laure Prunier ◽  
Raymond Schuch ◽  
Reinaldo E. Fernández ◽  
Anthony T. Maurelli
Keyword(s):  
Escherichia Coli ◽  
Genetic Structure ◽  
Nicotinic Acid ◽  
E Coli ◽  
Shigella Spp

ABSTRACT Comparison of nadA and nadB in 14 Shigella strains and enteroinvasive Escherichia coli versus E. coli showed that at least one locus is altered in all strains. These observations explain the characteristic nicotinic acid auxotrophy of Shigella organisms and are consistent with the previously identified antivirulence nature of these genes for these pathogens.

scholarly journals Occurrence of Escherichia coli in captive psittaciformes: antimicrobial susceptibility and virulence genes

2020 ◽  
Vol 21 ◽  
Author(s):  
Karine Louise Calaça ◽  
Renato Clini Cervi ◽  
Silvânia Andrade Reis ◽  
Iolanda Aparecida Nunes ◽  
Valéria de Sá Jayme ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Susceptibility ◽  
Virulence Genes ◽  
Susceptibility Testing ◽  
Metropolitan Region ◽  
Serum Resistance ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Hygienic Conditions

Abstract Captive Psittaciformes may harbor Gram-negative bacteria in their digestive tract, mainly due to poor hygienic conditions and confinement. The present study was carried out with the objective of isolating and identifying Escherichia coli in samples collected from Psittaciformes cages in 50 commercial establishments in the metropolitan region of Goiania, with subsequent antimicrobial susceptibility testing and detection of virulence genes. A total of 141 samples of excreta and swab samples from feeders and water bowls were collected, totaling 423 samples. Escherichia coli was isolated from 9.7% (41/423) samples: 12% (17/141) in excreta, 8.5% (12/141) in feed, and 8.5% (12 /141) in waterers. To determine the susceptibility profile of E. coli isolates, resistance to ciprofloxacin 4.9% (2/41), gentamicin 17.0% (7/41), doxycycline 34.1% (14/41), florfenicol 34.1% (14/41), trimethoprim 39.0% (16/41), tetracycline 41.5% (17/41), enrofloxacin 43.9% (18/41), amoxicillin 48.8% (20/41), neomycin 61.0% (25/41), and sulfonamide 90.2% (37/41) was determined. In 20 isolates, resistance was determined at 4 or more antimicrobials, seven of excreta (7/17), five of feed (5/12), and eight of waterers (8/12). One of the isolates from the waterers showed resistance to all antimicrobials. The iss gene was detected in three isolates, the tsh gene in three, the papC gene in two, traT and eae genes were not detected. In this study, it can be concluded that Psittaciformes commercialized as pet are carry E. coli isolates resistant to most commonly used antimicrobials, mainly sulfonamides and neomycin, besides having virulence and serum resistance genes, which highlights the possibility of the to cause disease in humans.

scholarly journals Environmental Growth Conditions Influence the Ability of Escherichia coli K1 To Invade Brain Microvascular Endothelial Cells and Confer Serum Resistance

1998 ◽  
Vol 66 (12) ◽  
pp. 5692-5697 ◽  
Author(s):  
Julie L. Badger ◽  
Kwang Sik Kim
Keyword(s):  
Escherichia Coli ◽  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Bacterial Growth ◽  
Growth Conditions ◽  
Brain Barrier ◽  
Microvascular Endothelial Cells ◽  
Serum Resistance ◽  
Brain Microvascular Endothelial Cells ◽  
E Coli

ABSTRACT A major limitation to advances in prevention and therapy of neonatal meningitis is our incomplete understanding of the pathogenesis of this disease. In an effort to understand the pathogenesis of meningitis due to Escherichia coli K1, we examined whether environmental growth conditions similar to those that the bacteria might be exposed to in the blood could influence the ability ofE. coli K1 to invade brain microvascular endothelial cells (BMEC) in vitro and to cross the blood-brain barrier in vivo. We found that the following bacterial growth conditions enhanced E. coli K1 invasion of BMEC 3- to 10-fold: microaerophilic growth, media buffered at pH 6.5, and media supplemented with 50% newborn bovine serum (NBS), magnesium, or iron. Growth conditions that significantly repressed invasion (i.e., 2- to 250-fold) included iron chelation, a pH of 8.5, and high osmolarity. More importantly, E. coli K1 traversal of the blood-brain barrier was significantly greater for the growth condition enhancing BMEC invasion (50% NBS) than for the condition repressing invasion (osmolarity) in newborn rats with experimental hematogenous meningitis. Of interest, bacterial growth conditions that enhanced or repressed invasion also elicited similar serum resistance phenotype patterns. This is the first demonstration that bacterial ability to enter the central nervous system can be affected by environmental growth conditions.

scholarly journals Serogroups and virulence genes of Escherichia coli isolated from psittacine birds

2011 ◽  
Vol 31 (10) ◽  
pp. 916-921 ◽  
Author(s):  
Terezinha Knöbl ◽  
André B.S Saidenberg ◽  
Andrea M Moreno ◽  
Tânia A.T Gomes ◽  
Mônica A.M Vieira ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Virulence Genes ◽  
Serum Resistance ◽  
Temperature Sensitive ◽  
E Coli ◽  
Cytotoxic Necrotizing Factor ◽  
Heat Stable ◽  
Genes Encoding ◽  
Cytotoxic Necrotizing Factor 1

Escherichia coli isolates from 24 sick psittacine birds were serogrouped and investigated for the presence of genes encoding the following virulence factors: attaching and effacing (eae), enteropathogenic E. coli EAF plasmid (EAF), pili associated with pyelonephritis (pap), S fimbriae (sfa), afimbrial adhesin (afa), capsule K1 (neu), curli (crl, csgA), temperature-sensitive hemagglutinin (tsh), enteroaggregative heat-stable enterotoxin-1 (astA), heat-stable enterotoxin -1 heat labile (LT) and heat stable (STa and STb) enterotoxins, Shiga-like toxins (stx1 and stx2), cytotoxic necrotizing factor 1 (cnf1), haemolysin (hly), aerobactin production (iuc) and serum resistance (iss). The results showed that the isolates belonged to 12 serogroups: O7; O15; O21; O23; O54; O64; O76; O84; O88; O128; O152 and O166. The virulence genes found were: crl in all isolates, pap in 10 isolates, iss in seven isolates, csgA in five isolates, iuc and tsh in three isolates and eae in two isolates. The combination of virulence genes revealed 11 different genotypic patterns. All strains were negative for genes encoding for EAF, EAEC, K1, sfa, afa, hly, cnf, LT, STa, STb, stx1 and stx2. Our findings showed that some E. coli isolated from psittacine birds present the same virulence factors as avian pathogenic E. coli (APEC), uropathogenic E. coli (UPEC) and Enteropathogenic E. coli (EPEC) pathotypes.

scholarly journals Genetic Structure and Distribution of Four Pathogenicity Islands (PAI I536 to PAI IV536) of Uropathogenic Escherichia coli Strain 536

2002 ◽  
Vol 70 (11) ◽  
pp. 6365-6372 ◽  
Author(s):  
Ulrich Dobrindt ◽  
Gabriele Blum-Oehler ◽  
Gabor Nagy ◽  
György Schneider ◽  
André Johann ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genetic Structure ◽  
Dna Sequences ◽  
Coli Strain ◽  
Open Reading Frames ◽  
Pathogenicity Islands ◽  
Virulence Determinants ◽  
Core Element ◽  
E Coli ◽  
Virulence Potential

ABSTRACT For the uropathogenic Escherichia coli strain 536 (O6:K15:H31), the DNA sequences of three pathogenicity islands (PAIs) (PAI I536 to PAI III536) and their flanking regions (about 270 kb) were determined to further characterize the virulence potential of this strain. PAI I536 to PAI III536 exhibit features typical of PAIs, such as (i) association with tRNA-encoding genes; (ii) G+C content differing from that of the host genome; (iii) flanking repeat structures; (iv) a mosaic-like structure comprising a multitude of functional, truncated, and nonfunctional putative open reading frames (ORFs) with known or unknown functions; and (v) the presence of many fragments of mobile genetic elements. PAI I536 to PAI III536 range between 68 and 102 kb in size. Although these islands contain several ORFs and known virulence determinants described for PAIs of other extraintestinal pathogenic E. coli (ExPEC) isolates, they also consist of as-yet-unidentified ORFs encoding putative virulence factors. The genetic structure of PAI IV536, which represents the core element of the so-called high-pathogenicity island encoding a siderophore system initially identified in pathogenic yersiniae, was further characterized by sample sequencing. For the first time, multiple PAI sequences (PAI I536 to PAI IV536) in uropathogenic E. coli were studied and their presence in several wild-type E. coli isolates was extensively investigated. The results obtained suggest that these PAIs or at least large fragments thereof are detectable in other pathogenic E. coli isolates. These results support our view that the acquisition of large DNA regions, such as PAIs, by horizontal gene transfer is an important factor for the evolution of bacterial pathogens.

scholarly journals Emerging coexistence of three PMQR genes on a multiple resistance plasmid with a new surrounding genetic structure of qnrS2 in E. coli in China

2020 ◽  
Author(s):  
ying tao ◽  
kaixin zhou ◽  
lianyan xie ◽  
yanping xu ◽  
lizhong han ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Resistance Genes ◽  
Acquired Resistance ◽  
Quinolone Resistance ◽  
Multiple Resistance ◽  
S1 Nuclease ◽  
E Coli ◽  
Resistance Plasmid ◽  
Horizontal Spread ◽  
First Time

Abstract Background: Quinolones are commonly used for treatment of infections by bacteria of the Enterobacteriaceae family. However, the rising resistance to quinolones worldwide poses a major clinical and public health risk. This study aimed to characterise a novel multiple resistance plasmid carrying three plasmid-mediated quinolone resistance genes in Escherichia coli clinical stain RJ749. Methods: MICs of ceftriaxone, cefepime, ceftazidime, ciprofloxacin, and levofloxacin for RJ749 and transconjugant c749 were determined by the Etest method. Conjugation was performed using sodium azide-resistant E. coli J53 strain as a recipient. The quinolone resistance-determining regions of gyrA, gyrB, parC, and parE were PCR-amplified. Results: RJ749 was highly resistant to quinolones, while c749 showed low-level resistance. S1-nuclease pulsed-field gel electrophoresis revealed that RJ749 and c749 both harboured a plasmid. PCR presented chromosomal mutation sites of the quinolone resistance-determining region, which mediated quinolone resistance. The c749 genome comprised a single plasmid, pRJ749, with a multiple resistance region, including three plasmid-mediated quinolone resistance (PMQR) genes (aac(6′)-Ib-cr, qnrS2, and oqxAB) and ten acquired resistance genes. One of the genes, qnrS2, was shown for the first time to be flanked by two IS26s. Three IS26-mediated circular molecules carrying the PMQR genes were detected. Conclusions: We revealed the coexistence of three PMQR genes on a multiple resistance plasmid and a new surrounding genetic structure of qnrS2 flanked by IS26 elements. IS26 plays an important role in horizontal spread of quinolone resistance.

scholarly journals Cloning and Sequencing of the Klebsiella pneumoniae O5wb Gene Cluster and Its Role in Pathogenesis

2000 ◽  
Vol 68 (5) ◽  
pp. 2435-2440 ◽  
Author(s):  
Susana Merino ◽  
Maria Altarriba ◽  
Luis Izquierdo ◽  
María Mercé Nogueras ◽  
Miguel Regué ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Gene Cluster ◽  
Genomic Library ◽  
Open Reading Frames ◽  
Serum Resistance ◽  
E Coli ◽  
Double Recombination ◽  
Uroepithelial Cells ◽  
K 12 ◽  
Type Strains

ABSTRACT One representative recombinant clone encoding Klebsiella pneumoniae O5-antigen lipopolysaccharide (LPS) was found upon screening for serum resistance in a cosmid-based genomic library ofK. pneumoniae KT769 (O5:K57) introduced intoEscherichia coli DH5α. A total of eight open reading frames (wb O5 gene cluster) were necessary to produce K. pneumoniae O5-antigen LPS in E. coliK-12. The enzymatic activities proposed for thewb O5 gene cluster are in agreement with the activities proposed for the biosynthesis of K. pneumoniaeO5-antigen LPS. Using the complete DNA sequence of the K. pneumoniae wb O5 gene cluster, we obtained (by single or double recombination) genetically well-characterized mutants devoid only of this O5-antigen LPS. Finally, using these O5−mutants and the corresponding wild-type strains or complemented mutants with the wb O5 gene cluster (O5+strains), we found that the presence of K. pneumoniaeO5-antigen LPS is essential for some pathogenic features like serum resistance, adhesion to uroepithelial cells, and colonization (experimental infections) of the urinary tract in rats.

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