Contribution of the traT Gene to Serum Resistance Among Clinical Isolates of Enterobacteriaceae

Kanukollu, Usha; Bieler, Sandra; Hull, Sheila I.; Hull, Roger

doi:10.1099/00222615-19-1-61

Cited by 19 publications

(14 citation statements)

References 31 publications

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“…The cloned traT gene increases the serum resistance of unencapsulated strains when present in low copy number, whereas with encapsulated strains, higher copy numbers of traT must be present to affect serum resistance (8). traT is always carried on large IncF plasmids (259,359). Although traT is more common among extraintestinal isolates (58%) than fecal strains (38%) (259), it is not clearly associated in the aggregate with serum resistance (259,359), except possibly among UTI isolates (359), a finding which casts doubt on the importance of traT as a significant determinant of serum resistance in pathogenic strains.…”

Section: Plasmid-associated Proteins In Serum Resistancementioning

confidence: 91%

“…Several phenotypic traits other than colicin production per se may contribute to the virulence associated with ColV plasmids, including autoagglutination and hypomotility at 37°C (which may impede phagocytosis) (464,542,543), enhanced survival in the mouse peritoneum (419), increased adherence to mouse intestinal cells and increased fimbriation (65), aerobactin production (see above), impaired phagocytosis (9), and increased serum resistance (9,29,30,259,373,498,540,541). pColV, I-K94 (a well-studied ColV plasmid) also confers increased acid susceptibility (72).…”

Section: Plasmid-associated Proteins In Serum Resistancementioning

confidence: 99%

“…Incompatibility group F plasmids, e.g., ColV plasmids (FI) and the resistance plasmids R100 and R6-5 (FII), are the best studied of these (30,259,358,540,541,545), although plasmids of other incompatibility groups (N, 0, S, T, and U) may also confer enhanced serum resistance (128).…”

Section: Plasmid-associated Proteins In Serum Resistancementioning

confidence: 99%

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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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Section: Plasmid-associated Proteins In Serum Resistancementioning

confidence: 91%

Section: Plasmid-associated Proteins In Serum Resistancementioning

confidence: 99%

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Virulence factors in Escherichia coli urinary tract infection

1991

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“…Plasmid conjugation is encoded in the tra region. It has been demonstrated that expression of traT genes might be involved in bacterial resistance to serum (181,270), biofilm development (141), and phagocytosis (3), therefore contributing to the virulent properties of bacteria carrying conjugative (frequently antibiotic resistance) plasmids.…”

Section: Evolution and Dissemination Of Genes Involved In Virulence Amentioning

confidence: 99%

Interactions among Strategies Associated with Bacterial Infection: Pathogenicity, Epidemicity, and Antibiotic Resistance

2002

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SUMMARY Infections have been the major cause of disease throughout the history of human populations. With the introduction of antibiotics, it was thought that this problem should disappear. However, bacteria have been able to evolve to become antibiotic resistant. Nowadays, a proficient pathogen must be virulent, epidemic, and resistant to antibiotics. Analysis of the interplay among these features of bacterial populations is needed to predict the future of infectious diseases. In this regard, we have reviewed the genetic linkage of antibiotic resistance and bacterial virulence in the same genetic determinants as well as the cross talk between antibiotic resistance and virulence regulatory circuits with the aim of understanding the effect of acquisition of resistance on bacterial virulence. We also discuss the possibility that antibiotic resistance and bacterial virulence might prevail as linked phenotypes in the future. The novel situation brought about by the worldwide use of antibiotics is undoubtedly changing bacterial populations. These changes might alter the properties of not only bacterial pathogens, but also the normal host microbiota. The evolutionary consequences of the release of antibiotics into the environment are largely unknown, but most probably restoration of the microbiota from the preantibiotic era is beyond our current abilities.

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“…Methods used for assay of hemolysin expression, serum resistance, and D-mannose-resistant hemagglutination (MRHA) of human erythrocytes have been described previously and were used without modification (9,12). Strains were identified as prototrophic or auxotrophic by testing for capacity to grow on minimal salts agar supplemented with 0.4% glucose (4).…”

Section: Methodsmentioning

confidence: 99%

Virulence Factors of Escherichia Coli Isolates From Patients With Symptomatic and Asymptomatic Bacteriuria and Neuropathic Bladders Due to Spinal Cord and Brain Injuries

Hull¹,

Rudy²,

Wieser³

et al. 1998

The Journal of Urology

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Chronic bacteriuria is a common occurrence among spinal-cord injury patients and others with neuropathic bladders. If bacteria are present in the urinary tract, the patient may develop symptoms of infection or remain asymptomatic. We have compared virulence properties of 28 Escherichia coli isolates from patients with symptomatic urinary tract infections (UTI) and 29 E. coli isolates from patients with asymptomatic bacteriuria (ABU). Bacteria from patients with symptomatic UTI were more likely to be hemolytic than isolates from patients with ABU (P ‫؍‬ 0.05) or fecal isolates obtained from healthy volunteers (P < 0.001). Bacteria from patients with symptomatic UTI were also more likely than strains isolated from patients with ABU (P ‫؍‬ 0.08) or fecal strains (P < 0.001) to exhibit D-mannose-resistant hemagglutination of human erythrocytes. The results suggest that E. coli isolates from nonimmunocompromised patients who require intermittent catheterization and who develop symptomatic UTI may be distinguished from bacteria recovered from patients who remain asymptomatic and possibly from normal fecal E. coli.Urinary tract infection (UTI) is a frequent medical complication during the initial medical and rehabilitation period after spinal-cord injury (SCI) and traumatic brain injury (TBI) and continues to be a problem throughout the life of many spinalcord-injured individuals. The urine of patients with neuropathic bladders frequently contains bacteria, and Escherichia coli is among the most frequent bladder colonizers (1,5,6). These bacteria may produce symptoms of UTI or may produce only asymptomatic bacteriuria (ABU). Bacteria associated with ABU are often left untreated and may even be beneficial in preventing symptomatic infection by more virulent organisms (16). Little is known at present about the virulence properties of E. coli bacteria that cause symptomatic UTI in patients with neuropathic bladders or how these strains may differ from benign colonizing strains. In the present study, approved by the Institutional Review Board of the hospital at which it was performed, we investigated selected virulence properties of E. coli isolates from SCI and TBI patients with UTI and ABU. Our hypothesis was that E. coli isolates from patients with symptomatic UTI possess virulence properties that may be used to distinguish them from other E. coli strains. MATERIALS AND METHODSPatient characteristics. Subjects were selected from patients admitted to a rehabilitation hospital between January 1994 and December 1996 with a diagnosis of SCI or TBI who were treated with intermittent catheterization and acquired at least one colonization of the urinary tract with E. coli. Twenty-five patients developed 28 symptomatic UTIs due to E. coli during that time. Of these 16 males and 9 females, 4 had TBI and 21 had SCI (12 tetraplegics and 9 paraplegics); the mean age was 39 (range, 7 to 75). Twenty-seven patients were colonized 29 times with E. coli but remained asymptomatic. Of these 15 males and 12 females, 1 had TBI and 19 had SC...

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Contribution of the traT Gene to Serum Resistance Among Clinical Isolates of Enterobacteriaceae

Cited by 19 publications

References 31 publications

Virulence factors in Escherichia coli urinary tract infection

Virulence factors in Escherichia coli urinary tract infection

Interactions among Strategies Associated with Bacterial Infection: Pathogenicity, Epidemicity, and Antibiotic Resistance

Virulence Factors of Escherichia Coli Isolates From Patients With Symptomatic and Asymptomatic Bacteriuria and Neuropathic Bladders Due to Spinal Cord and Brain Injuries

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