Three-year surveillance study of nosocomial bacterial resistance in Argentina. The Antimicrobial Committee; and the National Surveillance Program (SIR) Participants Group

Abstract

Introduction: A national surveillance program (SIR) was introduced in 1996 in Argentina by the Antimicrobial Committee of the Argentinean Society for Microbiology to assess bacterial resistance. The present study reports the rates of nosocomial bacterial resistance found by this program.

Methods: A 2-month point-prevalence study was conducted twice yearly (i.e., April-May and October-November) from 1996 to 1998, by 27 Argentinean centers. Susceptibility testing was carried out by the disk diffusion method following the National Committee for Clinical Laboratory Standards guidelines.

Results: In all, 6343 isolates recovered from 5603 inpatients (> or =48-hr hospitalization) were included. Methicillin resistance was 58% and 56% in Staphylococcus aureus and coagulase-negative staphylococci (CNS), respectively. Although no vancomycin resistance was found in staphylococci, 2% and 8% of the S. aureus and CNS strains, respectively, proved resistant to teicoplanin. No ampicillin resistance was displayed by Enterococcus faecalis. High-level gentamicin and streptomycin resistance in enterococci were 33% and 37%, respectively. Acquired glycopeptide resistance in enterococci emerged in 1997 (2%). Imipenem resistance in Acinetobacter spp and Pseudomonas aeruginosa was 9% and 21%, respectively. Among Enterobacteriaceae, 1% and 5% of the Klebsiella pneumoniae and Enterobacter cloacae isolates, respectively, proved resistant to imipenem. Ceftazidime and cefepime resistance was found in 63% and 33% of the E. cloacae strains. Resistance to extended-spectrum cephalosporins was shown by 48%, 26%, and 8% of the K. pneumoniae, Proteus mirabilis, and Escherichia coli isolates, respectively.

Conclusions: The alarming rates of resistance found in this study provide compelling evidence of the need for more rational use of antimicrobial agents in Argentina.