Comparison of Multiple-Locus Variable-Number Tandem-Repeat Analysis with Pulsed-Field Gel Electrophoresis, spa Typing, and Multilocus Sequence Typing for Clonal Characterization of Staphylococcus aureus Isolates

Abstract

Multiple-locus variable-number tandem-repeat analysis (MLVA), a new PCR-based method of typing Staphylococcus aureus, was compared to pulsed-field gel electrophoresis (PFGE), spa typing, and multilocus sequence typing (MLST) on a group of 59 S. aureus (mostly methicillin-resistant) clinical isolates. The aim of the study was to establish possible criteria of clustering MLVA patterns and to check concordance levels between the results produced by MLVA and the three other typing methods. As in our earlier study, MLVA turned out to have discriminatory power similar to that of PFGE. Comparison of data obtained by the two approaches allowed us to propose a 70% or ca. 80% cutoff value of the similarity between two MLVA patterns, depending on a cutoff level applied to interpret the PFGE results, 75% or ca. 90%, respectively. The cutoff values corresponded to the difference of up to six or four bands, respectively, among maximum 14 bands in total produced by two isolates in the analysis. The MLVA clusters matched well those obtained by PFGE, and they were also consistent in general with clusters generated by spa typing and MLST, these latter methods characterized lower resolution. Our results suggest that MLVA may be reliable in shorter-term S. aureus epidemiological studies, including analyses of outbreaks and hospital-to-hospital strain transmission events. Well-known advantages of typing methods based on PCR (low cost, short time, and easiness of performance) make MLVA a method that may be useful in a variety of laboratories, including those performing routine microbiological analyses within medical centers.

Staphylococcal Interspersed Repeat Unit Typing of Staphylococcus aureus : Evaluation of a New Multilocus Variable-Number Tandem-Repeat Analysis Typing Method

“…Our results show that SIRU typing analysis adds to the knowledge of the variability of the S. aureus genome and contributes to the understanding of genetic relationships among MRSA clones, as seen by Malachowa et al (44).…”

Core genome conservation of Staphylococcus haemolyticus limits sequence based population structure analysis

“…Other studies comparing MLVF to MLST have also shown a good concordance between type assignment made by the two methods (Malachowa et al, 2005). In contrast, Tenover et.al reported that MLVF can not be used to predict PFGE type (Tenover et al, 2007).…”

Overview of molecular typing methods for outbreak detection and epidemiological surveillance

“…In the spa sequence typing method, each identified repeat is associated to a code and a spa-type is deduced from the order of specific repeats. Although spa-typing has a lower discriminatory ability than PFGE [45,46], its cost-effectiveness, ease of use, speed, excellent reproducibility, appropriate in vivo and in vitro stability, standardised international nomenclature, high-throughput by using the StaphType software, and full portability of data via the Ridom database (http:// spaserver.ridom.de) makes this method the currently most useful instrument for characterising S. aureus isolates at the local, national and international levels [47][48][49][50][51][52]. Importantly, this approach ensures strict criteria for internal and external quality assurance of data submitted to the database that is curated by SeqNet.org [50,53].…”