[Pathogenicity islands in opportunistic Enterobacteria]

Area of Science:

• Microbiology
• Genetics
• Molecular Biology

Background:

• Pathogenicity islands (PAIs) are mobile genetic elements carrying virulence genes.
• Escherichia coli possesses well-characterized PAIs, including those encoding hemolysin (hlyA, hlyB), P-fimbriae (papAH, papC), and S-fimbriae (sfaG, sfaA).
• The K. pneumoniae capsule polysaccharide synthesis (KpsMT) locus is also a key virulence factor.

Purpose of the Study:

• To investigate the presence of E. coli PAI gene fragments in clinical strains of other Enterobacteriaceae genera.
• To assess the potential for horizontal gene transfer of virulence factors within the Enterobacteriaceae family.
• To compare the prevalence of these gene fragments across different genera and clinical origins.

Main Methods:

• Polymerase Chain Reaction (PCR) was used to detect specific DNA fragments.
• Clinical isolates from various Enterobacteriaceae genera (Citrobacter, Enterobacter, Hafnia, Klebsiella, Morganella, Proteus, Providencia, Serratia, Yersinia) were analyzed.
• Amplicons homologous to E. coli PAI genes (hlyA, hlyB, papAH, papC, sfaG, sfaA, kpsMT) were sought.

Main Results:

• Fragments of E. coli PAIs were detected in clinical strains of Citrobacter, Enterobacter, Hafnia, Klebsiella, Morganella, Proteus, Providencia, Serratia, and Yersinia.
• Amplicons for hlyB were less frequent in intestinal Enterobacteriaceae compared to non-intestinal strains.
• Amplicons for the pili gene (sfaG) were more frequent in Enterobacteriaceae strains from respiratory infections.
• Klebsiella spp. showed the most significant difference from E. coli in PAI gene fragment occurrence.
• Overall, PAI gene fragments were less frequent in the studied Enterobacteriaceae clinical strains compared to E. coli.

Conclusions:

• The study confirms the presence of E. coli PAI gene fragments in diverse Enterobacteriaceae genera, indicating horizontal gene transfer.
• Genetic exchange of DNA fragments between bacterial species is probable, potentially leading to altered pathogenicity.
• Klebsiella spp. appear to have a distinct pattern of PAI gene acquisition compared to E. coli.