Elastic Light Scatter Pattern Analysis for the Expedited Detection of Yersinia Species in Pork Mince: Proof of Concept

Abstract

Isolation of the pathogens Yersinia enterocolitica and Yersinia pseudotuberculosis from foods typically rely on slow (10–21 day) “cold enrichment” protocols before confirmed results are obtained. We describe an approach that yields results in 39 h that combines an alternative enrichment method with culture on a non-selective medium, and subsequent identification of suspect colonies using elastic light scatter (ELS) analysis. A prototype database of ELS profiles from five Yersinia species and six other bacterial genera found in pork mince was established, and used to compare similar profiles of colonies obtained from enrichment cultures from pork mince samples seeded with representative strains of Y. enterocolitica and Y. pseudotuberculosis. The presumptive identification by ELS using computerised or visual analyses of 83/90 colonies in these experiments as the target species was confirmed by partial 16S rDNA sequencing. In addition to seeded cultures, our method recovered two naturally occurring Yersinia strains. Our results indicate that modified enrichment combined with ELS is a promising new approach for expedited detection of foodborne pathogenic yersiniae.

Cold Enrichment Methods for the Detection of Foodborne Yersiniosis: Friend or Foe?

“…For strain ERL 10782 (Y. enterocolitica), neither yadA nor virF were detected by PCR, indicating that the plasmid detected was not pYV. The original seeding cultures in reference [8] are denoted by an asterisk, *. Reisolates refer to strains of that strain recovered after pork mince seeding studies [8] or experiments described in this paper.…”

“…The original seeding cultures in reference [8] are denoted by an asterisk, *. Reisolates refer to strains of that strain recovered after pork mince seeding studies [8] or experiments described in this paper. +, trait detected; -, trait not detected; Ye, Y. enterocolitica; Yp, Y. pseudotuberculosis; ERL, Enteric Reference Laboratory of the Institute of Environmental Science, New Zealand; ATCC, American Type Culture Collection, Virginia, MA, USA; NCTC, National Type Culture Collection, London, UK.…”

“…We recently described a novel, rapid (39 h) detection approach for Yersinia spp. in pork mince using an initial enrichment step at 37 • C combined with non-destructive, semi-automated isolate identification using Elastic Light Scatter analysis [8]. One of the anonymous referees for this paper explicitly questioned our method, declaring that "pYV could be lost and the colony morphology might be greatly affected."…”

“…In this paper, we investigate the impact of our protocol on pYV plasmid carriage, with special reference to the enrichment temperature of 37 • C used. Sixteen isolates representing one strain each of Y. enterocolitica and Y. pseudotuberculosis recovered from our original seeding experiments [8], and nine additional strains (see Section 3, Materials and Methods) subjected to the 37 • C + 28 • C enrichment protocol described, were examined for plasmid carriage using the QIAPrep spin miniprep assay. Plasmids were detected in every isolate examined both pre-and post-enrichment (Figure 1).…”

Antimicrobial Activity Derivatives 2H-pirano[2,3-c]piridines against Pathogens of Intestinal Yersiniosis

“…The expressed polymorphism of clinical manifestations and the difficulties of early laboratory diagnostics lead to diagnostic errors, recommending inadequate antibiotic therapy and, as a result, to the development of the disease complications with subsequent disability of the patient [9,10]. In this connection, Yersiniosis causes not only significant socio-economic losses but also constitute an important problem for human health [11,12]. An important aspect in the treatment of patients with intestinal yersiniosis is the administration of effective antibiotic therapy [13].…”