[Surveillance of antimicrobial resistance: VIRA study 2004]

The objective of the study was to know the current situation of the antimicrobial sensitivity patterns of the main multi-resistant bacteria and to analyze any possible changes with respect to the VIRA study carried out in 2001.

The 40 participating hospitals sent a total of 1,425 microorganisms isolated in February 2004, distributed as follows: penicillin-resistant Streptococcus pneumoniae (139), methicillin-resistant Staphylococcus aureus (289), clinically significant coagulase-negative staphylococci (158), ampicillin-resistant Enterococcus faecium (89) and Enterococcus faecalis (2), ampicillin-resistant Haemophilus influenzae (85), ciprofloxacin-resistant Escherichia coli (346), Pseudomonas aeruginosa (187), and Acinetobacter baumannii (130). The hospitals provided epidemiological data on these microorganisms. Sensitivity was determined by the broth microdilution method.

The number of highly penicillin-resistant pneumococci fell significantly (p < 0.0001) compared with the previous study (from 59.8% to 30.2%). Global methicillin-resistance in S. aureus was 31.2%, which represents a significant increase (p < 0.001) compared with the year 2001 (24.8%). 11.3% of the E. coli strains were extended-spectrum beta -lactamase-producers and came from 24 hospitals. One P. aeruginosa isolate gave a positive result in the E-test MBL assay, suggesting the presence of metallo-beta -lactamases. The strains of imipenem-resistant A. baumannii presented cross-resistance with several antibiotics.

These results show how the multi-resistant bacteria included in the study represent a growing problem in our hospitals. This emphasizes the importance of resistance surveillance systems and the correct use of antimicrobial agents.