Molecular and phenotypic detection of siderophore production by hypervirulent Klebsiella pneumoniae

Klebsiella pneumoniae is a highly prevalent pathogen among nosocomial and community- acquired infections, including urinary tract infections (UTIs), pneumonia, surgical site infections, and bloodstream infections. One hundred (100) isolates were obtained from different sources, including urine, burns, sputum, blood, and wound. All isolates were bacteriologically identified as Klebsiella pneumoniae using phenotypic and biochemical tests. The antimicrobial susceptibility test was done by using the disc diffusion method for thirteen different antimicrobial agents. String test was used to evaluate the hypermucoviscousity of the isolates and siderophore production was estimated by CAS agar and colorimetric methods. Two genes, iucA and iroB, were detected by PCR and their correlation with phenotypic markers was evaluated. The results showed that 51% of the isolates were positive for the string test and 49 % were negative. The results showed that the siderophores production ranged between 14 to 74 psu. Genotyping results showed that 23% of the isolates contained iucA gene and 17 % contained iroB. There was a high correlation between the two genes and the hypermucoviscousity. Also, siderophore production was highly associated with having one of the genes or both with more than 60 psu of siderophores production.