Copyright © 2012. . © 2012 Hoffman and Cawthorn

Aims: The detection of viable Enterobacter sakazakii cells is important due to the association of this pathogen with outbreaks of life-threatening neonatal infections. The aim of this study was to optimize a PCR-based method for selective detection of only viable Ent. sakazakii cells in the presence of dead cells, utilizing propidium monoazide (PMA) or ethidium bromide monoazide (EMA). Methods and Results: PMA or EMA was added to suspensions of viable and/or dead Ent. sakazakii cells at varying concentrations (10, 50 or 100 μg ml⁻¹) prior to DNA isolation and PCR with Ent. sakazakii-specific primers. At concentrations of 50 and 100 μg ml⁻¹, PMA completely inhibited PCR amplification from dead cells, while causing no significant inhibition of the amplification from viable cells. PMA was also effective in allowing selective PCR detection of only viable cells in mixtures of varying ratios of viable and dead cells. EMA was equally effective in preventing amplification from dead cells, however, it also inhibited DNA amplification from viable cells. Conclusions: This study demonstrated the efficiency of PMA for viable and dead differentiation of Ent. sakazakii, as well as the lack of selectivity of EMA for this purpose. Significance and Impact of the Study: PMA-PCR, in particular, will be useful for monitoring the resistance, survival strategies and stress responses of Ent. sakazakii in foods and the environment.

Consumers have the power to influence conservation of marine fishes by selectively purchasing sustainably harvested species. Yet, this power is hindered by vague labeling and seafood fraud, which may mask market biodiversity and lead to inadvertent consumption of threatened species. Here, we investigate the repercussions of such labeling inaccuracies for one of the world's most highly prized families of fishes‐–the snappers (Family: Lutjanidae). By DNA barcoding 300 “snapper” samples collected from six countries, we show that the lax application of this umbrella term and widespread mislabeling (40%) conceal the identities of at least 67 species from 16 families in global marketplaces, effectively lumping taxa for sale that derive from an array of disparately managed fisheries and have markedly different conservation concerns. Bringing this trade into the open should compel a revision of international labeling and traceability policies, as well as enforcement measures, which currently allow such extensive biodiversity to be consumed unknowingly.