Suitability of PCR fingerprinting, infrequent-restriction-site PCR, and pulsed-field gel electrophoresis, combined with computerized gel analysis, inlibrary typing of Salmonella enterica serovar enteritidis

Strains of Salmonella enterica (n = 212) of different serovars and phage ty pes were used to establish a library typing computerized system for serovar Enteritidis on the basis of PCR fingerprinting, infrequent-restriction-sit e PCR (IRS-PCR), or pulsed-field gel electrophoresis (PFGE). The rate of PC R fingerprinting interassay and intercenter reproducibility was low and was only increased when DNA samples were extracted at the same time and amplif ied with the same reaction mixtures. Reproducibility of IRS-PCR technique r eached 100%, but discrimination was low (D = 0.52), The PFGE procedure show ed an intercenter reproducibility value of 93.3%. The high reproducibility of PFGE combined with the previously determined high discrimination directe d its use for library typing. The use of PFGE with enzymes XbaI, BlnI, and SpeI for library typing of serovar Enteritidis was assessed with GelCompar 4.0 software, Three computer libraries of PFGE DNA profiles were constructe d, and their ability to recognize new DNA profiles was analyzed. The result s obtained pointed out that the combination of PFGE with computerized analy sis could be suitable in long-term epidemiological comparison and surveilla nce of Salmonella serovar Enteritidis, specially if the prevalence of genet ic events that could be responsible for changes in PFGE profiles in this se rovar was low.