Multi locus variable-number tandem repeat (MLVA) typing tools improved the surveillance of Salmonella enteritidis: a 6 years retrospective study

PLoS One. 2015 Feb 18;10(2):e0117950. doi: 10.1371/journal.pone.0117950. eCollection 2015.

Abstract

Surveillance of Salmonella enterica subsp. enterica serovar Enteritidis is generally considered to benefit from molecular techniques like multiple-locus variable-number of tandem repeats analysis (MLVA), which allow early detection and confinement of outbreaks. Here, a surveillance study, including phage typing, antimicrobial susceptibility testing and MLVA on 1,535 S. Enteritidis isolates collected between 2007 and 2012, was used to evaluate the added value of MLVA for public health surveillance in Belgium. Phage types PT4, PT8, PT21, PT1, PT6, PT14b, PT28 and PT13 dominate the Belgian S. Enteritidis population. The isolates of S. Enteritidis were most frequently susceptible to all antibiotics tested. 172 different MLVA profiles were detected, of which 9 frequent profiles included 67.2% of the S. Enteritidis population. During a serial passage experiment on selected isolates to investigate the in vitro stability of the 5 MLVA loci, no variations over time were observed indicating that the MLVA profiles were stable. The MLVA profile of isolates originating from different outbreaks in the Democratic Republic of the Congo (DRC) between 2010 and 2011 were distinct from any of the MLVA profiles found in Belgian isolates throughout the six year observational period and demonstrates that MLVA improves public health surveillance of S. Enteritidis. However, MLVA should be complemented with other subtyping methods when investigating outbreaks is caused by the most common MLVA profile.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Bacterial Typing Techniques / methods*
  • Disease Outbreaks
  • Genetic Loci / genetics*
  • Humans
  • Minisatellite Repeats*
  • Public Health Surveillance / methods*
  • Retrospective Studies
  • Salmonella Infections / epidemiology
  • Salmonella enteritidis / classification*
  • Salmonella enteritidis / drug effects
  • Salmonella enteritidis / genetics*
  • Salmonella enteritidis / isolation & purification

Substances

  • Anti-Bacterial Agents

Grants and funding

The authors received no specific funding for this work, but the Belgian reference center for Salmonella is partially supported by the Belgian Ministry of Social Affairs through a fund within the Health Insurance System. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.