Pseudomonas aeruginosa is an opportunistic human pathogen that causes many infections such as urinary tract, respiratory tract, burn infections in addition to septicemia. Iron (Fe) is an essential element for the growth of most living microorganisms. Siderophores are iron chelating compounds produced by bacteria. Ps. aeruginosa produces two major siderophores; pyoverdine and pyochelin.
Ps. aeruginosa isolates were identified morphologically, biochemically and by culture characteristics. Siderophore production was assessed phenotypically by chrome azurol sulfonate (CAS) Shuttle assay and genotypically by PCR.
Siderophore production varied among the clinical isolates. High production was found in 63.33% of isolates. Intermediate production of siderophore was detected in 30%, while 6.66% of isolates showed a low level of siderophores. Genotypic detection of genes responsible for the formation of siderophores and their receptors revealed the presence of PvdS, PtxR and FpvA genes that are responsible for pyoverdine synthesis and its receptor formation in all isolates. Whereas pchG and FptA encoding pyochelin and its receptor were detected in 85.7% of isolates.
Siderophores are important iron chelators in Ps. aeruginosa. Substantial correlation was received from the genotypic and phenotypic investigations of siderophore production.