Identification of Escherichia coli clinical isolates producing macrolide 2'-phosphotransferase by a highly sensitive detection method.

Macrolide is inactivated with ATP plus crude extract of Escherichia coli producing macrolide 2'-phosphotransferase (MPH(2')), but not by living cells. Therefore, a convenient method for detection of MPH(2') using intact cells is needed. In this report, we determine that the modified lysozyme-DNase-RNase (LDR) method (named ELDR method) is at least one hundred times more sensitive for the detection of MPH(2') activity than the LDR method and, in addition, highly sensitive for the detection of aminoglycoside-modifying enzymes. Therefore, three new MPH(2')-producing strains were found in clinically isolated E. coli in Japan in 1997 by this method. It suggests that MPH(2')-producing E. coli have been spread in Japanese clinical fields.