Nosocomial lower respiratory tract infections: prevalence and risk factors in 14 Greek hospitals.

Nosocomial lower respiratory tract infections (NLRTIs) are associated with significant morbidity and mortality. The aim of this study was to investigate the epidemiological features of NLRTIs in Greece, where knowledge about these infections is limited. Two point-prevalence studies of hospital-acquired infections were carried out in 14 Greek hospitals located throughout the country, one in 1999 and one in 2000. NLRTIs were diagnosed in accordance with the Centers for Disease Control and Prevention (CDC) definitions. Among the 7,120 hospitalized patients registered during the two studies, 610 (8.6%) cases of hospital-acquired infections were identified, of which 200 (32.8%) were NLRTIs. Sixty-nine (34.5%) patients had pneumonia, and the remaining 131 (65.5%) patients had bronchitis. The greatest prevalence of NLRTI was found in the adult ICUs (30.4%). Male gender, age >65 years, mechanical ventilation, tracheostomy, an intravenous central line, and an indwelling urethral catheter were the main risk factors. There was no significant difference in the incidence of NLRTI among hospital-acquired infections between the 1999 study and the 2000 study. The causative microorganism was identified in 78 of 200 (39%) cases, and 103 strains were isolated. The majority of strains (67%) were gram-negative bacteria. The most frequently isolated microorganisms were Pseudomonas aeruginosa (22.3%), Acinetobacter spp. (19.4%), Klebsiella pneumoniae (12.6%), and Staphylococcus aureus (10.7%). There was no difference between the two prevalence studies in the frequency of isolation of the microorganisms. NLRTI was the leading cause of morbidity and mortality among hospitalized patients with hospital-acquired infections in Greek hospitals. Gram-negative microorganisms were the most frequently isolated pathogens.