DNA microarray analysis of Staphylococcus aureus causing bloodstream infection: bacterial genes associated with...

Area of Science:

• Microbiology
• Infectious Diseases
• Genetics

Background:

• Staphylococcus aureus bloodstream infections (SABSI) pose significant challenges due to complex microbe-host interactions.
• Previous research suggested an association between S. aureus clonal complex (CC) 30 and SABSI mortality.
• Understanding the genetic basis of S. aureus virulence is crucial for improving patient outcomes.

Purpose of the Study:

• To investigate the genetic profiles of S. aureus isolates from SABSI patients.
• To test the hypothesis that specific S. aureus genetic factors are associated with mortality in SABSI.
• To compare genetic characteristics between SABSI isolates and asymptomatic carrier strains.

Main Methods:

• DNA microarray analysis and spa typing were used to characterize 305 SABSI isolates and 38 S. aureus CC30 carrier isolates.
• Statistical analyses, including Fisher's exact test, LASSO, and elastic net regressions, were employed.
• Isolates were grouped based on patient outcome and characteristics for detailed analysis.

Main Results:

• No specific S. aureus genetic determinants were directly associated with mortality in SABSI patients.
• AgrIII and cna genes were positively associated, while setC and seh were negatively associated with S. aureus CC30 compared to non-CC30 isolates.
• Genes chp and sak, involved in immune evasion, were more frequent in CC30 SABSI isolates than CC30 carrier isolates, suggesting higher virulence.

Conclusions:

• This study did not identify specific S. aureus genes linked to mortality in SABSI using DNA microarray and advanced statistical methods.
• Genetic differences were observed between CC30 and non-CC30 isolates, and between infection and carrier strains.
• Future research with whole genome sequencing in larger cohorts is recommended to further elucidate genetic associations with SABSI outcomes.