Effects of gastric alkalization on bacterial colonization in critically ill patients

Gastric alkalization of critically ill patients is associated with bacterial and fungal overgrowth in gastric contents. We studied the incidence of gastric colonization and its relation to other infections and antibiotic therapy in 25 critically ill ICU patients. All patients received 12-h NG Mylanta II and 15 received an H2-receptor antagonist. All patients had bacterial colonization of NG contents within 4 days of ICU admission and 10 had Candida colonization within 8 days. There were 70 NG isolates and the same isolates were found in tracheobronchial secretions (n = 46), blood (n = 4), urine (n = 4), and wounds (n = 8). Tracheobronchial colonization was preceded by NG colonization with the same organism in 12 instances (11 patients), was concurrent with NG colonization in 20 instances (14 patients), was followed by NG colonization in 14 instances (11 patients), and had no similar NG isolate in 18 instances (11 patients). NG culture of the same organism preceded four of eight positive blood cultures. In 35 of 70 NG isolates and five of 11 subsequent tracheobronchial isolates, colonization occurred despite concurrent appropriate antibiotics. We conclude that colonization of alkalinized NG contents is universal, is a common source of infection in other areas, and is not prevented by systemic antibiotic therapy. Local antibiotic therapy may be important in controlling this important source of infection.