Dissemination and diversity of metallo-β-lactamases in Latin America:: report from the SENTRY Antimicrobial Surveillance Program

Carbapenem resistance among Pseudomonas aeruginosa and Acinetobacter spp. is becoming a critical therapeutic problem worldwide. The SENTRY Antimicrobial Surveillance Program monitors pathogen frequency and antimicrobial resistance patterns of nosocomial and community-acquired infections through sentinel hospitals on five continents. Pseudomonas spp. and Acinetobacter Spp. strains resistant to imipenem (MIC, greater than or equal to 16 mg/l), meropenem (MIC, greater than or equal to 16 mg/l), and ceftazidime (MIC. greater than or equal to32 mg/l) collected from January 2001 to December 2003 were routinely screened for antimicrobial resistance genes. Resistant isolates were initially tested for metallo-beta-lactamase (MbetaL) production by phenotypic tests (disk approximation or MbetaL Etest strip) and then characterization of the MbetaL (hydrolysis assays, PCR for bla(IMP). bla(VIM), bla(SPM) gene sequencing). Eighty-nine isolates (33 Acinetobacter spp., 54 Pseudomonas aeruginosa. and 2 P. fluorescens) had positive phenotypic screening tests. Among those, 34 isolates producing MbetaL were identified, including 7 Acinetobacter spp., 25 P aeruginosa and 2 R fluorescens. The MbetaLs identified were IMP-1. VIM-2 and two newly described enzymes: SPM-1 and IMP-16. The greatest concentration of MOL strains was in Brazil, where imipenem-resistant P. aeruginosa increased significantly in the time period evaluated by the SENTRY Program. MbetaL-producing P aeruginosa was detected in Sao Paulo (SPM-1) and Brasilia (SPM-1 and IMP-16). Brazil and Caracas, Venezuela (VIM-2); while MbetaL-producing Acinetobacter spp. isolates were detected in Sao Paulo, Brazil (IMP-1). P. fluorescens isolates producing IMP-1 and VIM-2 were detected in Sao Paulo, Brazil and Santiago, Chile, respectively. The emergence and dissemination of mobile NXIOLproducing isolates represent an alarming factor for increasing resistance to carbapenems in several medical centres evaluated by the SENTRY Program in Latin America. (C) 2004 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.