SERE, a widely dispersed bacterial repetitive DNA element

Area of Science:

• Microbiology
• Genetics
• Molecular Biology

Background:

• The sefABCD operon encodes fimbrial proteins crucial for Salmonella Enteritidis virulence.
• A conserved Salmonella Enteritidis repeat element (SERE) is located upstream of the sefABCD operon.
• SERE is widely distributed across bacterial and archaeal kingdoms.

Purpose of the Study:

• To report the presence and characteristics of the Salmonella Enteritidis repeat element (SERE).
• To develop a novel SERE-based polymerase chain reaction (SERE-PCR) assay for bacterial fingerprinting.
• To evaluate the utility of SERE-PCR for differentiating Salmonella Enteritidis isolates.

Main Methods:

• DNA dot-blot hybridization and genetic database searches were employed to characterize SERE.
• A SERE-based polymerase chain reaction (SERE-PCR) assay was developed.
• Fifty-four Salmonella Enteritidis isolates (nine phage types) and 54 other Salmonella serotypes were analyzed using SERE-PCR.

Main Results:

• SERE was found to be conserved and widely distributed in bacteria and archaea.
• SERE-PCR identified five distinct fingerprint profiles among Salmonella Enteritidis isolates.
• No correlation was observed between phage types and SERE-PCR fingerprint patterns.
• The SERE-PCR assay demonstrated reproducibility, speed, and ease of use.

Conclusions:

• The Salmonella Enteritidis repeat element (SERE) is a conserved genetic marker.
• SERE-PCR is a rapid and reproducible method for fingerprinting Salmonella isolates.
• Limited heterogeneity in SERE-PCR patterns suggests potential for serotype- and serogroup-specific differentiation of Salmonella Enteritidis.