The impact of Candida albicans colonization in the airway on ventilator-associated pneumonia caused by Pseudomonas aeruginosa

Abstract

Objective  To investigate the impact of Candida albicans colonization on the mortality, duration of antibiotic therapy, immune and inflammation status in patients with ventilator-associated pneumonia (VAP) caused by multidrug-resistant Pseudomonas aeruginosa. Methods  This prospective multicenter cohort study included patients with VAP caused by multidrug-resistant Pseudomonas aeruginosa (MDR-Pa) admitted to six tertiary teaching hospitals from June 2018 to June 2023. The patients were divided into colonization group and non-colonization group based on the presence of Candida albicans detected in the broncho-alveolar lavage fluid (BALF). The 30-d all-cause mortality, duration of antibiotic therapy, immune and inflammation status were compared between the two groups after VAP diagnosis on the day1, day3, day5, and day7. Results  During the five-year research period, a total of 232 VAP patients caused by MDR-Pa were included from six participating units in the intensive care unit (ICU), with 105 cases in the colonization group and 127 cases in the non-colonization group. The Pseudomonas aeruginosa detected in BALF samples from the non-colonization group showed higher sensitivity to aminoglycosides, cephalosporins, and carbapenems compared to the colonization group (P<0.05). However, both groups showed lower sensitivity to 16 antibiotics compared to China antimicrobial surveillance network (CHINET) 2022 (P<0.05).  Interleukin-17A and (1,3)-β-D glucan levels in the non-colonization group were consistently lower than those in the colonization group at various time points, and other inflammatory markers were more likely to return to normal values (P<0.05). Additionally, the absolute values of T and Th lymphocytes in the non-colonization group recovered to normal levels faster on the day 7 (P<0.05). There was no statistically significant difference in the 30-d all-cause mortality between the two groups (25.7% vs 22.8%, P=0.61), but the non-colonization group had a significantly shorter duration of antibiotic therapy compared to the colonization group ［(11.3±3.1)d vs （14.2±4.7)d, P<0.01］, with a trend towards shorter ICU hospitalization time. Conclusion  The colonization of Candida albicans in the airway does not affect the 30-d all-cause mortality of patients with VAP caused by MDR-Pa. However, it does prolong the inflammatory response and the duration of antibiotic use, as well as delay the recovery of immune function.

Keywords

ventilator-associated pneumonia / Candida albicans / Pseudomonas aeruginosa / colonization / co-exist