[Antibiotic resistance in blood isolates of Staphylococcus aureus in 31 Spanish hospitals participating in the European Antimicrobial Resistance Surveillance System (2000)].

BACKGROUND

In 1998, the European Union funded the European Antimicrobial Resistance Surveillance System. We present here Staphylococcus aureus data in 2000 in Spain.

MATERIAL AND METHOD

31 hospitals were involved, covering almost 25% Spanish total population. All nosocomial blood isolates of S. aureus were included. Each laboratory carried out microbiological studies with its own usual methods. Quality control was carried out by UK National External Quality (NEQAS). A questionnaire including hospital, patient and specimen data was filled out for each isolate. Results were registered in a single database and analyzed and validated with Whonet. 5 software.

RESULTS

Invasive S. aureus was isolated in 903 patients. Overall incidence was 1.45/1000 admitted patients. Resistance was 28.1% (95% CI, 25.2-31.1) to oxacillin (O), 26.6% to ciprofloxacin (C), 23.8% to erythromycin (E) and 16.6% to gentamicin (G). Multiresistance was noticed in 80% oxacillin-resistant strains. More frequent multiresistance profiles were OECG (11.3% of all isolates) and OEC (6.3%). Oxacillin resistance was higher in ICU units (44.5%) than in other medical departments (27.4%) (p < 0.001). Hospitals with 500 beds or more showed 36.4% prevalence of O resistance, while in hospitals having less than 500 beds it was 18.8% (p < 0.001). A decreased susceptibility to vancomycin was not detected.

CONCLUSIONS

In Spain, invasive S. aureus shows a high prevalence of resistance to oxacillin, ciprofloxacin, erythromycin and gentamicin. Most oxacillin-resistant strains were resistant to three or more antibiotics. Nearly 50% oxacillin-resistant isolates were susceptible to gentamicin. Oxacillin resistance and resistance to multiple antibiotics was more frequent in ICU units and in hospitals with 500 beds or more.