Prevalence of infection by carbapenem-resistant Acinetobacter baumannii in Spain (1999-2005)

This study determines the prevalence of infections by carbapenem-resistant Acinetobacter baumannii (CRAB) in Spain, and identifies trends over time, geographical variations, and factors associated with resistance. Yearly prevalence surveys (EPINE, Estudio de Prevalencia de las Infecciones Nosocomiales en España) during 1999 to 2005 were analyzed, including data on the site of infection, culture, and antimicrobial susceptibility, and characteristics of the patients and hospitals. On average, 246 hospitals/year participated in the survey. A total of 1168 A. baumannii isolates were identified, yielding an infection prevalence rate of 3/1,000 hospitalized patients. Fourteen percent of isolates were related to community-onset infections. The most frequent sites of infection were the respiratory tract (42.2%), surgical wound (15.1%), urinary tract (12.9%), and skin (11.7%). Rate of carbapenem resistance was 34.5% (95% CI, 31.8-37.3), and was even higher among ICU patients (43.8%; 95% CI, 38.9%-48.7%). There were considerable differences between Spanish regions, with the highest rates of resistance in central regions. Higher resistance rates were observed in respiratory tract infections (43%) and catheter-related bacteremia (47.6%) than among other sites of infection (P =.003). Main factors associated with CRAB identified by multivariate analysis were surgical or tracheostomy procedures, use of invasive devices such as urinary, nasogastric, or central venous catheters, and mechanical ventilation, as well as male gender and pressure sores. The prevalence of CRAB in Spain is very high. Differences in resistance rates have been observed according to geographic region and area of hospitalization. Several invasive procedures, as well as male gender and pressure sores, are associated with higher rates of carbapenem resistance.