PCR detection of aminoglycoside resistance genes: a rapid molecular typingmethod for Acinetobacter baumannii

Aminoglycoside resistance is common among strains of Acinetobacter baumanni i responsible for nosocomial infections, and inactivation of these antibiot ics by enzymatic modification is the main mechanism. Different types of ami noglycoside acetyltransferases (AAC), nucleotidyltransferases (ANT), and ph osphotransferases (APH) are synthesized by clinical isolates, and several e nzymes can be produced by a single strain. Using a multiplex PCR procedure carried out on bacterial thermolysates, we analyzed the aminoglycoside resi stance gene content of strains belonging to eight clusters identified by pu lsed-field gel electrophoresis. In a single reaction were combined three pr imer pairs in order to amplify the genes coding for AAC(6')-Ih, AAC(3)-I, a nd AAC(3)-II, three primer pairs for the genes coding for ANT(2 ")-I, APH(3 ')-VI, and rRNA 16S as internal control, and finally two primer pairs for t he genes coding for AAC(6')-Ib and APH(3')-I. According to the aminoglycosi de resistance gene patterns, the strains of the eight clusters were distrib uted into seven classes. This simple and rapid (< 8 h) fingerprinting techn ique could be a useful tool for the epidemiological investigation of A. bau mannii nosocomial infections. (C) Elsevier, Paris.