Background
The understanding of high mortality associated with intra-abdominal candidiasis (IAC) remains limited. While
Candida
is considered a harmless colonizer in the digestive tract, its role as a true pathogen in IAC is still debated. Evidence regarding
Candida
virulence in the human peritoneal fluid are lacking. We hypothesized that during IAC,
Candida albicans
develops virulence factors to survive to new environmental conditions. The objective of this observational exploratory monocentric study is to investigate the influence of peritoneal fluid (PF) on the expression of
C. albicans
virulence using a multimodal approach.
Materials and methods
A standardized inoculum of a
C. albicans
(3.10
6
UFC/mL) reference strain (SC5314) was introduced in vitro into various PF samples obtained from critically ill patients with intra-abdominal infection. Ascitic fluids (AFs) and Sabouraud medium (SBD) were used as control groups. Optical microscopy and conventional culture techniques were employed to assess the morphological changes and growth of
C. albicans
. Reverse transcriptase qPCR was utilized to quantify the expression levels of five virulence genes. The metabolic production of
C. albicans
was measured using the calScreener™ technology.
Results
A total of 26 PF samples from patients with secondary peritonitis were included in the study. Critically ill patients were mostly male (73%) with a median age of 58 years admitted for urgent surgery (78%). Peritonitis was mostly hospital-acquired (81%), including 13 post-operative peritonitis (50%). The infected PF samples predominantly exhibited polymicrobial composition. The findings revealed substantial variability in
C. albicans
growth and morphological changes in the PF compared to ascitic fluid. Virulence gene expression and metabolic production were dependent on the specific PF sample and the presence of bacterial coinfection.
Conclusions
This study provides evidence of
C. albicans
virulence expression in the peritoneal fluid. The observed variability in virulence expression suggests that it is influenced by the composition of PF and the presence of bacterial coinfection. These findings contribute to a better understanding of the complex dynamics of intra-abdominal candidiasis and advocate for personalized approach for IAC patients.
Trial registration
https://clinicaltrials.gov/
(NCT05264571; February 22, 2022)
Graphical Abstract
Highlights
This study is the first to demonstrate the expression of
Candida albicans
virulence in human peritoneal fluid.
The expression of
Candida albicans
virulence in peritoneal fluid shows significant variability among critically ill patients with intra-abdomina...

Reappraisal of intra-abdominal candidiasis: insights from peritoneal fluid analysis

10.1186/s40635-023-00552-0