The Novel CTX-M-116 β-Lactamase Gene Discovered in Proteus mirabilis Is Composed of Parts of the CTX-M-22 and CTX-M-23 Genes

The novel β-lactamase gene blaCTX-M-116 was identified in a Proteus mirabilis nosocomial isolate recovered from the urine of a patient in Moscow in 2005. DNA sequence analysis showed blaCTX-M-116 to be a hybrid gene consisting of 5′ blaCTX-M-23 (nucleotides 1 to 278) and 3′ blaCTX-M-22 (nucleotides 286 to 876) moieties separated by an intervening putative site of recombination (GTTAAAT). A retrospective analysis of available blaCTX-M genes in the GenBank database revealed 19 blaCTX-M genes that display the same hybrid structure.