[Focus and value of the assay of 5 beta-lactams using high-performance liquid chromatography]

Severe infectious diseases treatment often needs a frequent antimicrobial agent blood levels control. These controls are still performed by microbiological assay procedure. High performance liquid chromatography (HPLC) is now allowing a new kind of assay procedure and improves on speed, specificity and sensitivity. We developed a procedure allowing us to monitor every day by routine, five beta-lactam antibiotics with only one analytical column: benzylpenicillin, ampicillin, cloxacillin, mezlocillin and cefotaxime. A single extraction procedure suitable to the five beta-lactam antibiotics and to various body fluids and the use of three mobile phases, permit us to give a quick answer to the clinicians and thus to consider a rapid adaptation of the doses being administered. In consideration of the specificity, it is possible to control blood levels of each beta-lactam antibiotic even by associated antimicrobial treatment, what is sometimes impossible using the microbiological assay procedure. Cefotaxime is well separated from its active metabolite desacetyl-cefotaxime. The disparity of the levels obtained, for the same posology, essentially by prematures and new-borns, but also in case of massive infusions for endocarditis justify the use of a rapid and specific procedure like high performance liquid chromatography (HPLC).