A novel functional class 2 integron in clinical Proteus mirabilis isolates

Results: Class 1 integrons were detected in 96 (63%) of 153 Proteus isolates: eight different gene cassette arrays were detected, includingdfrA32-ereA1-aadA2, which was detected for the first time inP.mirabilis. Class 2 integrons were detected in 101 (66%) of 153 Proteus isolates: four different gene cassette arrays were detected, including dfrA1-catB2-sat2-aadA1, which was detected for the first time in a class 2 integron. A novel functional class 2 integron was detected in 38P.mirabilis isolates with a common promoter (235 TTTAAT|16 bp|210 TAAAGT). The variable region of this functional class 2 integron containeddfrA14 and three novel open reading frames with unknown functions. Very similar ERIC– PCR fingerprinting patterns were detected in these 38 P. mirabilis isolates and were different from other class 2 integron-positive isolates. Conclusions: A novel functional class 2 integron was found for the first time inP.mirabilis. These functional class 2 integron-harbouring P. mirabilis isolates were likely to be clonally spread in our hospital.