Test-system "Biolactam" as an efficient means for detection of bacteria resistant to beta-lactam antibiotics
We have designed the test system BioLactam what is capable of registering the level of beta-lactamase activity in biological substrates. In the present study we have evaluated the fundamental possibility of determination of beta-lactamase activity of bacterial suspension using the above mentioned test system; also we have performed the analysis of equivalence of acquired results to the data of routine methods of bacteriological examination. It was demonstrated that test system BioLactam may be successfully used for qualitative and quantitative evaluation of beta-lactamase activity of bacterial suspensions, and the results of testing are in good concordance with those got by disk diffusion method. By the use of test system BioLactam we can determine the following eventswith the high level of reliability: 1) production of significant quantities of beta-lactamases if the level of beta-lactamase activity of bacterial suspension ≥ 14,2%; 2) resistance to inhibitor-protected beta-lactams if the level of beta-lactamase activity of bacterial suspension ≥ 26,5%; 3) resistance to cephalosporins of 3rd generation if the level of beta-lactamase activity ≥81,2%; 4) if used together with disk diffusion method - also the presence of non-enzymatic mechanisms of resistance to beta-lactam antibiotics. Test system BioLactam is optimal for determining of resistance level of enterobacteria to beta-lactam antibiotics; it may be of limited use for determination of gram positive cocci resistance to these preparations and doesn't allow to directly differentiate ESBLs and ordinary beta-lactamases.