New resistance mechanism of escherichia coli to beta-lactamins

ABSTRACT

Escherichia coli is the germ most frequently isolated in espicially urinary infections. The perpetual change of its sensitivity profile to beta-lactamins is [due to several evolution factors. Some strains have acquiered resistance by gene mutation or by acquisition of movable genetic material. Also phenomenon as impermeability, excretion by efflux system or modifying penicillin liaison proteins could be seen but the production of beta-lactamases remains the most frequent mechanism of resistance that has been describe until now. The authors report, through this observation, a case of a particular strain of Escherichia coli that has been isoleted from urine of an hospitalized patiente. This strain presented an hyperproduction of cefalosporinases, which is a recently discovered mechanism of resistance. In one hand, specific bacteriologic tests as synergy test, antagonism test and the use of cloxacillin added antibiogramme on Mueller-Hinton medium were carried out and have allowed to display the phenotypic aspect of this mechanism. In the other hand, its genetic aspect was mentionned through a new literature data. The authors have also underlined the importance of the antibiogramme prior to any prescription of antibiotics which could put pressure on the germ leading to a selection of individual resistant, to this kind of difficul not controlled resistance and many potential complications ensue from it