Antimicrobial resistance among Gram-negative bacilli isolated from Latin America: results from SENTRY Antimicrobial Surveillance Program (Latin America, 2008-2010)

Abstract

This study updates the frequency and resistance rates of Gram-negative bacilli isolated from Latin American medical centers enrolled in the SENTRY Antimicrobial Surveillance Program. A total of 12,811 bacterial organisms, including 5704 Gram-negative bacilli (44.5%), were consecutively collected (1 per patient) between January 2008 and December 2010 from 10 Latin American medical centers located in Argentina, Brazil, Chile, and Mexico. Antimicrobial susceptibility testing was performed and interpreted by the Clinical and Laboratory Standards Institute broth microdilution method at a central laboratory. All Gram-negative organisms with reduced susceptibility to imipenem or meropenem (MIC, ≥ 2 μg/mL) were screened for carbapenemase production by the modified Hodge test and by polymerase chain reaction. ESBL rates were 18.1%, 12.8%, 23.8%, and 48.4% among Escherichia coli and 60.4%, 49.9%, 59.2%, and 33.3% among Klebsiella spp. from Argentina, Brazil, Chile, and Mexico, respectively. Meropenem-nonsusceptible Klebsiella spp. rate was highest in Brazil (11.1%), followed by Argentina (8.2%), Chile (5.0%), and Mexico (0.8%). Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae was not detected in 2008, but emerged in 2009 (10 strains) and increased significantly in 2010 (44; P < 0.0001). bla(KPC-2) was detected in 54 (65.9%) of 85 carbapenem-nonsusceptible K. pneumoniae. Meropenem-nonsusceptible P. aeruginosa was observed in 53.8%, 46.7%, 33.3%, and 28.8% of strains from Argentina, Brazil, Chile, and Mexico, respectively. Imipenem-resistant Acinetobacter spp. rates increased from 6.4%, 12.6%, and 0.0% in the 1997-1999 period to 84.9%, 71.4%, and 50.0% in 2008-2010 in Argentina, Brazil, and Chile, respectively. Oxacillinase (OXA)-producing Acinetobacter spp. was documented in Argentina (OXA-23 and -24), Brazil (OXA-23), Chile (OXA-58), and Mexico (OXA-24). Only colistin showed >77% overall coverage against the 5 most frequently isolated Gram-negative bacilli from Latin American Medical centers participating in the SENTRY Program.