Fees for PFGE Typing:
Within New York State: $115 per enzyme per isolate
Outside of New York State: $130 per enzyme per isolate
Note: Standard protocols for Salmonella and E. coli require 1 enzyme, while Listeria requires two enzymes; hence the cost for PFGE typing Salmonella or E. coli is $115 or $130 per isolate, while the cost for PFGE typing Listeria is $230 or $260 per isolate.
What is Pulsed Field Gel Electrophoresis (PFGE)?
PFGE is a molecular fingerprinting technique used to classify bacteria based on restriction sites within the bacterial genome beyond the species level. The process involves embedding the organism in agarose, lysing the organism in situ, and digesting the genomic DNA with a restriction endonuclease that recognizes specific sequences in the bacterial genome typically producing 10-20 fragments. Since these DNA fragments are too large to separate by conventional agarose gel electrophoresis, the use of an alternating voltage gradient system known as pulsed-field gel electrophoresis was developed. The fragments are then resolved into a pattern based on molecular size. Standard PFGE can resolve DNA fragments from 2 Mb to 20 kb. The patterns that are produced can then be analyzed to determine relatedness (Figure 1 & 2). Our laboratory follows the CDC PulseNet protocol guidelines for PFGE and uses BioNumerics analysis software to produce high-quality, reproducible results with increased comparability of patterns.
Why PFGE / Advantages?
PFGE analysis can aid in epidemiological investigation by providing rapid detection of outbreak-related cases, distinguishing outbreaks strains from other strains, as well as tracking contamination within a food system. Subtyping by PFGE is currently considered the "gold-standard" for subtyping many pathogenic organisms. PFGE has repeatedly shown to be more discriminative than other methods such as ribotyping for many bacteria1. Currently we have over 6000 Salmonella patterns and 1700 Listeria monocytogenes patterns in our database for comparison.