Xanthomonas maltophilia and Pseudomonas cepacia in lower respiratory tracts of patients in critical care units.

Xanthomonas maltophilia and Pseudomonas cepacia are Gram-negative bacilli that are considered to opportunistic pathogens. These bacteria may cause colonization and infection, especially in acutely ill patients. Between 1 July 1990 and 30 June 1992 sputum [correction of suptum] culture results from patients in the critical care units were surveyed daily. During the 2 year period, sputum from 27 patients grew X. maltophilia. It was hospital-acquired in 26 patients. A total of 26 patients were mechanically ventilated for between 1 day and 8 months (median 19 days) before sputum cultures grew X. maltophilia. Various antimicrobial agents were prescribed for 25 of the 27 patients before they acquired X. maltophilia infection. The case fatality was 44.4%. Sputum from 79 patients grew P. cepacia. It was hospital-acquired in all who were ventilated for between 1 day and 50 days (median 9 days) before sputum cultures grew P. cepacia. Several antimicrobial agents were given to 77 patients before P. cepacia was isolated from them. The case fatality rate was 51.9%. In the majority of cases, the positive cultures indicated colonization. Patients with APACHE II scores >15 experienced a higher fatality (55.6% vs. 22.2%, P<0.05 for X. maltophilia and 56.9% vs.28.6%, P<0.05 for P. cepacia).