Ability of genotypical method to make assesment of tuberculosis infection hotbed

Abstract

A comparison of 142 positive results of culture test on L-Y media and Xpert MBT / RIF test was performed. The material for research was sputum collected for the diagnosis of a new TB case. In group 1 there were 52 results with scanty, in group 2–40 results with moderate, in group 3–50 results with massive bacterial excrection. Evaluation of the positive Xpert MBT / RIF test make according to the number of copies of DNA: very small, small, medium quantity, great quantity. Correlation analysis was performed in the statistical program SPPS. Xpert MBT / RIF: in group 1 26.9% – negative results, 23.1% – very small, 38.5% – small, 7.7%, – medium, 3.8% – great quantity; in the 2nd group 2.5% – negative results, 5.0% – very small, 35.0% – small, 47.5% – the medium quantity, 10.0% – a great quantity; in group 3, very small and small had 2.0% of the results, 34.0% – the medium quantity, 62.0% – a great quantity. Culture test on the L-Y media is more specific and allows to detect additionally more than 10% of patients, the result of correlation analysis gives an opportunity to recommend the use of the data of genotyping test Xpert MBT / RIF with indication of quantitative characteristics for prediction of level of bacterial excrection, early assessment of the danger of the hotbed of tuberculosis infection for planning of epidemiological surveillance and infection control.