Producers of metallo-beta-lactamases (MBLs) have been shown to confer resistance to carbapenems. The present study was undertaken to evaluate the presence of resistance to imipenem and oxymino cephalosporins, as well as MBLs production among clinical isolates of Pseudomonas aeruginosa in João Pessoa-PB, Brazil. A total of 198 non-repetitive strains of P. aeruginosa identified by routine techniques were studied. These strains were screened for MBL production, using the double disk diffusion test previously described by Arakawa et al. (2000), as modified by Nakajima et al. (2001), using disks containing sodium mercaptoacetate as inhibitor of MBL. Strains were considered to be MBL producer when they demonstrated a typical expansion in the inhibitory zone by the presence of thiol compound. A total of four strains (2%) showed positive results among the isolates tested. Our findings indicate that the appearance of metallo-beta-lactamase in Pseudomonas aeruginosa strains is an emerging problem, with important therapeutic implications, and this fact needs further investigation including the use of molecular methodologies to fully characterize the extent of the problem.
Pseudomonas aeruginosa; Resistance; Metallo-beta-lactamases
