jejuni isolates. Figure 1 Diversity of PFGE profiles. #GDC-0068 randurls[1|1|,|CHEM1|]# This picture shows the diversity of the C. jejuni PFGE profiles from the same processing plant but different years. PFGE patterns re-appeared at different years, suggesting that few predominant PFGE patters are associated to a given processing plant. A cut-off of 90%, based on previous studies [32, 36], was used to separate PFGE subtypes. Table 6 Comparison of the Simpson’s index of diversity (SID) between C. jejuni and C. coli Species Number of unrelated strains Number of types SID C. coli 78 24 0.924 C. jejuni

175 87 0.982 C. jejuni by year       2005 15 14 0.989 2006 19 11 0.918 2007 39 22 0.950 2008 23 20 0.988 2009 15 11 0952 2010 31 20 0.959 2011 33 25 0.979 Discussion There have not been recent reports on the prevalence of Campylobacter in retail broiler meat in the USA. Most of the studies include products with skin, and the samples are taken during processing where the carcasses are still intact and before portioning. The more recent publication summarizing the prevalence of Campylobacter spp. in processed carcasses comes from the

nationwide microbiological baseline data collection program by the USDA FSIS. These data were collected from July 2007 through June 2008 and showed a prevalence of 40% Campylobacter positive in carcasses post-chill [7]. Yet, most of the broiler meat sold in stores across the US is sold in tray packs and include boneless, skinless CB-839 purchase products. Because Campylobacter spp. are at low numbers in retail broiler meat in the USA [7], concentration by centrifugation [21] and filtration have been performed to increase

the number of Campylobacter cells before plating [8, 22]. Bolton broth was used in this study because this medium has been used most frequently for isolation of Campylobacter from poultry samples [23, 24], and it appears to be one of the best available alternatives to compromise between the inhibition of competitors and the growth of Campylobacter spp. [25]. The data in Table 1 are similar to most recent reports on the prevalence of Campylobacter spp. in retail samples in the US [9, 10, 21]. This prevalence is similar to the data from Belgium [26], but lower than the reports from Ireland [27], England over [28, 29], Canada [30], Japan [31] and Spain [32]. The prevalence among different countries varies from as low as 25% in Switzerland to as high as 100% in the Czech Republic [31, 33, 34]. The low prevalence of Campylobacter spp. in tenderloins has been previously reported [9, 10]. The fluctuation in the prevalence of C. coli and C. jejuni by year has not been previously addressed. However, more surveillance data is necessary to understand the extent of this fluctuation, which may be comprised of an actual variability by year and/or an artifactual variability due to the methodology used for isolation. It has been shown that analyzing more than 25 g of sample increases the chances of recovering positive samples for Campylobacter spp. [35].