Pulsed-Field Gel Electrophoresis (PFGE) employs an alternating field of electrophoresis to allow separation of the large DNA fragments obtained from genomic restriction digests with rare-cutting enzymes. Crucial to PFGE is the extraction of intact chromosomal DNA, which may render the technique more time consuming than other fingerprinting strategies. On the other hand, since PFGE profiles contain large DNA fragments that together represent the whole bacterial genome, this technique displays a superior discriminatory power at strain level.
At BCCM/LMG, PFGE is offered as a customer service for typing of isolates from clinical outbreaks, strain authenticity verifications in patent cases, genome evolution studies, etc. One major application illustrating the value of PFGE is its use as standardized epidemiological typing tool in the US network PulseNet coordinated by the Centers for Disease Control and Prevention (CDC). PulseNet keeps a cumulative PFGE database representing nearly half a million isolates of bacteria from food, the environment, and human foodborne illness for monitoring purposes.
BCCM/LMG has expertise in PFGE typing of lactic acid bacteria (e.g. lactobacilli, enterococci), bifidobacteria, Bacillus and E. coli. Upon request, and if numbers are sufficient, we can also optimize protocols for other bacterial groups. PFGE profiles are generated using a CHEF mapper pulsed-field electrophoresis system (Bio-Rad).
The service report includes a technical description of the protocol and visual interpretation of digitized profiles. On request, we can also perform clustering analysis of PFGE fingerprints using BioNumerics v7.0 software, and compare these with previous or future isolates that a customer has/will send us.
Literature
Masco L, Huys G, De Brandt E, Temmerman R, Swings J. 2005. Culture-dependent and culture-independent qualitative analysis of probiotic products claimed to contain bifidobacteria. Int J Food Microbiol 102:221-230. doi:10.1016/j.ijfoodmicro.2004.11.018
Vancanneyt M, Huys G, Lefebvre K, Vankerckhoven V, Goossens H, Swings J. 2006. Intraspecific genotypic characterization of Lactobacillus rhamnosus strains intended for probiotic use and isolates of human origin. Appl Environ Microb 72:5376-5383. doi: 10.1128/AEM.00091-06
Vankerckhoven V, Huys G, Vancanneyt M, Snauwaert C, Swings J, Klare I, Witte W, Van Autgaerden T, Chapelle S, Lammens C, Goossens H. 2008. Genotypic diversity, antimicrobial resistance, and virulence factors of human isolates and probiotic cultures constituting two intraspecific groups of Enterococcus faecium isolates. Appl Environ Microb 74:4247-4255. doi: 10.1128/AEM.02474-07