A second large plasmid encodes conjugative transfer and antimicrobial resistance in O119:H2 and some typical O111 enteropathogenic \u3ci\u3eEscherichia coli\u3c/i\u3e strains

A novel and functional conjugative transfer system identified in O119:H2 enteropathogenic Escherichia coli (EPEC) strain MB80 by subtractive hybridization is encoded on a large multidrug resistance plasmid, distinct from the well-described EPEC adherence factor (EAF) plasmid. Variants of the MB80 conjugative resistance plasmid were identified in other EPEC strains, including the prototypical O111:NM strain B171, from which the EAF plasmid has been sequenced. This separate large plasmid and the selective advantage that it confers in the antibiotic era have been overlooked because it comigrates with the virulence plasmid on conventional gels

A Second Large Plasmid Encodes Conjugative Transfer and Antimicrobial Resistance in O119:H2 and Some Typical O111 Enteropathogenic Escherichia coli Strains▿ §

A novel and functional conjugative transfer system identified in O119:H2 enteropathogenic Escherichia coli (EPEC) strain MB80 by subtractive hybridization is encoded on a large multidrug resistance plasmid, distinct from the well-described EPEC adherence factor (EAF) plasmid. Variants of the MB80 conjugative resistance plasmid were identified in other EPEC strains, including the prototypical O111:NM strain B171, from which the EAF plasmid has been sequenced. This separate large plasmid and the selective advantage that it confers in the antibiotic era have been overlooked because it comigrates with the virulence plasmid on conventional gels

Prognostic Modeling in Desmoplastic Melanoma Using Different Cutpoints for the Proportion of Desmoplasia

Currently, desmoplastic melanomas are commonly divided into “pure” desmoplastic melanoma (at least 90% desmoplasia histologically) and “mixed” (<90%), with pure having a better prognosis, but our understanding of the relationship between percent desmoplasia and prognosis is incomplete. We sought to determine whether a more refined grading system that examined extent of desmoplasia by percent in 10% increments would be a better prognostic model. We also sought to determine the optimal cutpoint for percent desmoplasia if a single cutpoint were used.We analyzed 103 patients with desmoplastic melanoma confined to the skin at diagnosis and who were followed for at least 6 months. Desmoplasia proportions ranged from 10% to 100%, with forty patients (38.4%) having 100% desmoplasia. Overall, eighteen patients (17.5%) eventually developed metastases. Those with 100% desmoplasia had a statistically significantly decreased likelihood of metastasis compared to those with <100% desmoplasia (OR=0.15, p=0.017). However, there was no trend towards decreased likelihood of metastasis with decreasing percentages below 100% (p=0.658), implying a graduated system did not appear to be a better model than a single cutpoint. We also found that a model for predicting metastasis that incorporated Breslow thickness and the presence or absence of 100% desmoplasia (Akaike information criterion (AIC) = 84.64) was better than a model using 90% desmoplasia as the cutpoint (AIC = 89.35). We determined that a single cutpoint is sufficient in modeling prognosis for desmoplastic melanoma, and that 100% desmoplasia is a better cutpoint than the 90% cutpoint found in the “pure/mixed” model currently in use

Prognostic Modeling in Desmoplastic Melanoma Using Different Cutpoints for the Proportion of Desmoplasia

Currently, desmoplastic melanomas are commonly divided into “pure” desmoplastic melanoma (at least 90% desmoplasia histologically) and “mixed” (<90%), with pure having a better prognosis, but our understanding of the relationship between percent desmoplasia and prognosis is incomplete. We sought to determine whether a more refined grading system that examined extent of desmoplasia by percent in 10% increments would be a better prognostic model. We also sought to determine the optimal cutpoint for percent desmoplasia if a single cutpoint were used.We analyzed 103 patients with desmoplastic melanoma confined to the skin at diagnosis and who were followed for at least 6 months. Desmoplasia proportions ranged from 10% to 100%, with forty patients (38.4%) having 100% desmoplasia. Overall, eighteen patients (17.5%) eventually developed metastases. Those with 100% desmoplasia had a statistically significantly decreased likelihood of metastasis compared to those with <100% desmoplasia (OR=0.15, p=0.017). However, there was no trend towards decreased likelihood of metastasis with decreasing percentages below 100% (p=0.658), implying a graduated system did not appear to be a better model than a single cutpoint. We also found that a model for predicting metastasis that incorporated Breslow thickness and the presence or absence of 100% desmoplasia (Akaike information criterion (AIC) = 84.64) was better than a model using 90% desmoplasia as the cutpoint (AIC = 89.35). We determined that a single cutpoint is sufficient in modeling prognosis for desmoplastic melanoma, and that 100% desmoplasia is a better cutpoint than the 90% cutpoint found in the “pure/mixed” model currently in use