In House Rapid, Simple Multiple-Locus Variable-Number Tandem Repeat Analysis (MLVA): A Reliable Tool for Enterobacter...

Area of Science:

• Microbiology
• Genomics
• Epidemiology

Background:

• Enterobacter hormaechei, part of the Enterobacter cloacae complex, is a major cause of hospital-acquired infections.
• Multidrug resistance is a common challenge with E. hormaechei, necessitating rapid diagnostic and surveillance tools.
• Genomic comparison is crucial for timely infection control strategies.

Purpose of the Study:

• To develop a simple, rapid multiple-locus variable-number tandem-repeat analysis (MLVA) protocol for E. hormaechei epidemiological surveillance.
• To assess the discriminatory power of the developed MLVA protocol.
• To compare MLVA performance against whole-genome sequencing (WGS) as a gold standard.

Main Methods:

• Eight variable-number tandem-repeat (VNTR) regions were amplified using multiplex PCR.
• Amplified products were analyzed via gel electrophoresis.
• The MLVA protocol was validated on 46 unrelated strains, outbreak-related strains, and VIM-producing strains, with WGS used for comparison.

Main Results:

• MLVA demonstrated comparable discriminatory power to multilocus sequence typing (MLST) for unrelated E. hormaechei strains (36 profiles vs. 33 sequence types).
• MLVA successfully identified unique profiles for epidemic strains during potential outbreaks, correlating with low single nucleotide polymorphism (SNP) distances in WGS.
• The protocol showed consistent MLVA profiles within the same sequence types for VIM-producing strains.

Conclusions:

• The developed MLVA protocol is a rapid, cost-effective tool for epidemiological investigations of E. hormaechei.
• MLVA can effectively screen for clonal groups and rapidly rule out unrelated strains.
• While valuable for screening, WGS remains essential for detailed analysis when MLVA profiles are similar.