1151 - Candida Colonization Alters Pathogenic Pulmonary Infection in Pediatric Patients with Cystic Fibrosis

Background: Isolation of Candida from the respiratory tract of patients with cystic fibrosis (CF) is common, but its clinical significance remains unclear. We evaluated whether pediatric Candida colonization is associated with specific risk factors, co-pathogens, and degree of respiratory disease.

Methods: Using the Military Healthcare System database, we identified 273 pediatric patients with CF who were followed for 938 person-years between 2012 and 2017. To determine whether prevalence was associated with different categorical variables, Fisher’s exact tests were performed on 1000 random samples with the constraint that exactly one interval was selected from each individual to generate each sample. When appropriate, follow-up binomial tests were performed to identify species differences. Individuals with a specific Candida species isolated in ≥50% of their respiratory cultures were considered colonized. Those with C. albicans were analyzed separately from all other Candida species. FEV₁ values < 80% predicted were used as a surrogate for degree of respiratory disease.

Results: Candida colonization was not associated with degree of respiratory disease, exocrine pancreatic insufficiency, co-existing diabetes, or the presence of a homozygous F508del CFTR mutation. C. albicans colonization differed by age, and was least prevalent amongst 0-2 year olds (p=0.031) (Fig 1). Compared to those either not colonized with Candida, or colonized with a species other than C. albicans, patients colonized with C. albicans had lower rates of co-infection with Aspergillus (p = 0.041) (Fig 2).   Significant differences in Candida colonization between groups was also notable for those colonized with Stenotrophomonas (p=0.014) and Nontuberculous Mycobacterium (p < 0.01), but not for Staphylococcus aureus or Pseudomonas (all p > 0.1).  Figure 1. C. albicans prevalence differed by age group (p<0.01). Specifically, prevalence was lower in the 0-2 year old age group (p=0.031).
Figure 2. Individuals were grouped into those without a Candida infection (None), those with non-C. albicans colonization (Other), and those with C. albicans colonization. No differences were found with respect to co-infection with MRSA, MSSA, or Pseudomonas. Significant differences were found with respect to Stenotrophomonas (p=0.014), Aspergillus (p < 0.01), and NTM (p < 0.01). The prevalence of Aspergillus in those individuals with C. albicans was lower compared to those with a different Candida infection or no Candida infection (p=0.041). The prevalence of co-infection with Stenotrophomonas was somewhat elevated among those with a non-C. albicans infection (p=0.052).


Conclusion: C. albicans likely plays a role in influencing the airway microbiome of patients with CF. The significance of colonization with other Candida species warrants further exploration.   Our data suggests that further studies are needed to evaluate whether Candida may be seen as protective against certain pathogens and therefore this may influence recommendations to treat patients who have CF with antifungals.