Typing based on polymorphic tandem repeats is becoming popular for Acinetobacter baumanii population analysis in spite of the relative scarcity of this class of markers and the heterogeneity of the species which makes primer design sometimes difficult.
Ten loci have been shown to be of potential use so far, and two combination of loci have been proposed to make Multiple Loci Variable Number of Tandem Repeats (VNTR) Analysis assays (MLVA). They have been described in details in by Hauck et al., PLoS One 2012, Pourcel et al., J. Clin. Mic. 2011.
One assay comprises 8 loci and is called MLVA8Orsay in the MLVA database to reflect the fact that other selection of 8 loci might be proposed in the future by other groups. The second assay with higher discriminatory power comprises all 10 loci and is called MLVA10Orsay.
The ten loci can be typed in two multiplex PCRs as shown using a capillary electrophoresis equipment.
1-Diversity of Acinetobacter baumannii in Four French Military Hospitals, as Assessed by Multiple Locus Variable Number of Tandem Repeats Analysis. Hauck Y, Soler C, Jault P, Mérens A, Gérome P, Nab CM, Trueba F, Bargues L, Thien HV, Vergnaud G, Pourcel C. PLoS One. 2012;7(9):e44597.]
2-Evidence of diversity among epidemiologically related carbapenemase-producing Acinetobacter baumannii strains belonging to international clonal lineage II. Minandri F, D’Arezzo S, Antunes LC, Pourcel C, Principe L, Petrosillo N, Visca P. J Clin Microbiol. 2012 Mar;50(3):590-7.
3-Identification of variable-number tandem-repeat (VNTR) sequences in Acinetobacter baumannii and interlaboratory validation of an optimized multiple-locus VNTR analysis typing scheme. Pourcel C, Minandri F, Hauck Y, D’Arezzo S, Imperi F, Vergnaud G, Visca P. J Clin Microbiol. 2011 Feb;49(2):539-48.