Pathogenic synergy between Escherichia coli and Bacteroides fragilis or B. vulgatus in experimental infections: a non-specific phenomenon

Vught, A. M. J. J. Verweij-Van; Namavar, F.; Vel, W. A. C.; Sparrius, M.; Maclaren, D. M.

doi:10.1099/00222615-21-1-43

Cited by 19 publications

(12 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This has been reported previously for abscess models using nondiabetic mice, and this ability may be a major factor in B. fragilis being identified at high frequencies in diabetic infections (5,8,9). While there are numerous reports of B. fragilis providing synergy to other organisms in cutaneous abscess models (5,8,42,43), we did not observe this except in the case of C. perfringens in the young mice at day 1 postinfection (Fig. 2).…”

Section: Discussioncontrasting

confidence: 49%

Synergy in Polymicrobial Infections in a Mouse Model of Type 2 Diabetes

Mastropaolo¹,

Evans

Byrnes

et al. 2005

Infect Immun

View full text Add to dashboard Cite

Human diabetics frequently suffer delayed wound healing, increased susceptibility to localized and systemic infections, and limb amputations as a consequence of the disease. Lower-limb infections in diabetic patients are most often polymicrobial, involving mixtures of aerobic, facultative anaerobic, and anaerobic bacteria. The purpose of this study is to determine if these organisms contribute to synergy in polymicrobial infections by using diabetic mice as an in vivo model. The model was the obese diabetic mouse strain BKS.Cg-m ؉/؉ Lepr db /J, a model of human type 2 diabetes. Young (5-to 6-week-old) prediabetic mice and aged (23-to 24-week-old) diabetic mice were compared. The mice were injected subcutaneously with mixed cultures containing Escherichia coli, Bacteroides fragilis, and Clostridium perfringens. Progression of the infection (usually abscess formation) was monitored by examining mice for bacterial populations and numbers of white blood cells at 1, 8, and 22 days postinfection. Synergy in the mixed infections was defined as a statistically significant increase in the number of bacteria at the site of injection when coinfected with a second bacterium, compared to when the bacterium was inoculated alone. E. coli provided strong synergy to B. fragilis but not to C. perfringens. C. perfringens and B. fragilis provided moderate synergy to each other but only in young mice. B. fragilis was anergistic (antagonistic) to E. coli in coinfections in young mice at 22 days postinfection. When age-matched nondiabetic mice (C57BLKS/J) were used as controls, the diabetic mice exhibited 5 to 35 times the number of CFU as did the nondiabetic mice, indicating that diabetes was a significant factor in the severity of the polymicrobial infections.

show abstract

Section: Discussioncontrasting

confidence: 49%

Synergy in Polymicrobial Infections in a Mouse Model of Type 2 Diabetes

Mastropaolo¹,

Evans

Byrnes

et al. 2005

Infect Immun

View full text Add to dashboard Cite

show abstract

“…Bacterial synergism in abscess formation has been demonstrated in several animal models (4,20,29). The role of Hbp in bacterial synergism was investigated by screening E. coli strains (Table 1) for their capacity to induce a synergistic interaction with B. fragilis in a mouse model (29).…”

Section: Resultsmentioning

confidence: 99%

“…A skin infection model in mice (29) was used to investigate the possible role of Hbp in the pathogenic synergism. E. coli strains and B. fragilis BE1 (Table 1) were cultured and subsequently injected into mice as described previously (29). The inoculum size for E. coli was 5 ϫ 10 6 CFU, and that for B. fragilis BE1 was 2 ϫ 10 8 CFU.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Escherichia coli Hemoglobin Protease Autotransporter Contributes to Synergistic Abscess Formation and Heme-Dependent Growth of Bacteroides fragilis

Otto¹,

Dooren²,

Dozois

et al. 2002

Infect Immun

View full text Add to dashboard Cite

Intra-abdominal infections (IAI) continue to be a serious clinical problem. Bacterial synergism is an important factor that influences the shift from contamination to IAI, leading to the development of lesions and abscess formation. Escherichia coli and Bacteroides fragilis are particularly abundant in IAI. The underlying molecular mechanisms of this pathogenic synergy are still unclear. The role of the hemoglobin protease (Hbp) autotransporter protein from E. coli in the synergy of IAI was investigated. Hbp is identical to Tsh, a temperature-sensitive hemagglutinin associated with avian pathogenic E. coli. Clinical isolates from miscellaneous extraintestinal infections were phenotypically and genotypically screened for Hbp. The presence of Hbp was significantly associated with E. coli isolated from IAI and other extraintestinal infections. In a murine infection model, Hbp was shown to contribute to the pathogenic synergy of abscess development. Mice immunized with Hbp were protected against mixed infections and did not develop abscess lesions. Furthermore, an E. coli wild-type strain that did not induce abscess formation in the synergy model was transformed with a plasmid encoding the hbp gene, and mixed infections with this strain lead to increased growth of B. fragilis and induction of abscess lesions. Growth-promoting studies showed that purified Hbp is able to deliver heme to B. fragilis strain BE1. In conclusion, results suggest the synergy of abscess formation by E. coli and B. fragilis can be partly explained by the capacity of B. fragilis to intercept Hbp and iron from heme to overcome the iron restrictions imposed by the host.

show abstract

“…The clinical isolate B. fragilis BE1 [17] was used as a source of chromosomal DNA for cloning and PCR experiments and for functional studies on the P46 a-enolase. E. coli TOP10F' (Invitrogen) and the plasmid pACYC184 [18] were used in routine cloning procedures [19].…”

Section: Bacterial Strains Plasmids and Mediamentioning

confidence: 99%