Assessing the clinical value for beta-lactamase activity of oral fluid

Zhyltsou I., Torosyan T., Semenov V., Egorov S.

Vitebsk State Medical University, Vitebsk, Republic of Belarus

The purpose of the present study was to determine whether the level of oral fluid beta-lactamase activity has an impact on the effectiveness of starting empirical antibiotic therapy prescribing to the patients with purulent-inflammatory diseases (PID) of the maxillofacial region (MFR), and whether one can use this characteristic for the optimization of antibiotic therapy.
Materials and methods. Experimental group of patients with PID MFR (n=158) was composed of patients with therapeutic (n=57) and surgical (n=101) PID MFR. The control group (n=52) was composed of virtually healthy individuals. Determination of the levels of beta-lactamase activity of oral fluid was carried out by spectrophotometric registration of decay of synthetic beta-lactam antibiotic of cephalosporin group nitrocefin, or cefinase.
Results. It has been found that the oral fluid of patients with therapeutic and surgical PID MFR possesses some beta-lactamase activity in 97,4% of cases, and variability of its levels is high (0-94,3%). The average level of beta-lactamase activity of oral fluid in the patients group was 39,6% what was reliably (р≤0,0026) higher than this one of control group (18%). According to the ROC-analysis data, the range of values of beta-lactamase activity of oral fluid between 40% and 70% corresponds to the possible presence of resistance to beta-lactam antibiotics of the first line (in particular, to the 3rd generation cephalosporins), whereas the level of activity above 70% corresponds to the probable presence of such resistance. Overall risk of failure of starting empirical antibacterial therapy in the subgroup of patients with beta-lactamase activity of oral liquid ≥40% was 3-12 times higher, and in the subgroup of patients with activity level ≥70% – in 4-14 times higher than in patients with beta-lactamase activity of oral fluid <40%.
Conclusion. At the level of beta-lactamase activity of oral fluid of patients with PID MFR within 40-70% one should recommend the prescription of inhibitor-protected beta-lactams and/or antibiotics from other pharmacological groups, and if this level of activity is >70% – one should mandatory prescribe these antibiotics.