Characterization of plasmids and plasmid-associated determinants of Yersinia enterocolitica pathogenesis

Abstract

Yersinia enterocolitica isolates harboring a particular species of plasmid deoxyribonucleic acid showed a high degree of lethality for gerbils and caused the detachment of HEp-2 tissue cell monolayers. Strains cured of their plasmid deoxyribonucleic acid showed loss of these properties. However, invasiveness of HEp-2 cells was shown not to be a plasmid-mediated property. The expression of plasmid-associated properties, including at least three major outer membrane polypeptides, occurred during growth at 37 but not at 25°C and was related to the concentration of calcium in the growth medium. The plasmid species associated with these properties ranged in molecular mass from 40 x 106 to 48 x 106 daltons and comprised a family of related plasmids.

Monoclonal antibodies directed against plasmid-encoded released proteins of enteropathogenic Yersinia

“…. A plasmid of 42-46 MDa is required for the expression of virulence by these different species [6][7][8] (reviewed in [9]), and these plasmids are closely related on the basis of DNA sequence homology [10,11]. Recently, several virulence-associated Yersinia proteins were identified as being plasmid-encoded.…”

Outbreak of extended-spectrum β-lactamase producing Serratia marcescens in an intensive care unit

“…The introduction into therapeutic practice of the wide spectrum third generation cephalosporins and monobactam antibiotics, which are resistant to the hydrolytic activity of the j3lactamases most commonly produced by Enterobacteriaceae, has facilitated the treatment of the most serious infections produced by these bacteria; their indiscriminate use has, however, favoured the emergence of /~-lactamases with a wider spectrum of action, responsible for patterns of/3-1actam resistance [7,[16][17][18]20].…”

“…The use of classic /3-1actam antibiotics such as the first generation cephalosporins, for preventive as well as therapeutic purposes, as in surgery, selects the strains which produce these enzymes. Among Enterobacteriaceae, K. pneumoniae is by far the most common species in which these enzymes have been recognized [2,7,8,10,[16][17][18]; however, many other Gram-negative rods, including Serratia marcescens, can produce enzymes that hydrolize the ~-lactam antibiotics newly introduced in clinical therapy. This is particularly important in intensive care wards which represent the main source of nosocomial infections due to Gram-negative bacteria.…”

“…Plasmid DNA was detected using the rapid alkaline lysis technique of Portnoy et al [18]. Samples were subjected to electrophoresis through 0.7% agarose gel at 5 V cm-1.…”

Association of colony morphology with virulence of Yersinia enterocolitica

“…The V and W antigens of Y. enterocolitica have been now shown to be immunologically identical to those of Y. pestis and Y. pseudotuberculosis [4]. Several other studies have also associated similar plasmid species ranging from M r 40-48.106 in size with the invasiveness of Y. enteroco#tica [5][6][7][8] and Y. pestis [9] and correlated their presence to tissue culture cytotoxicity and to expression of several major outer membrane proteins [7].…”