A Comparison of Culture- and PCR-Based Methods to Detect Six Major Non-O157 Serogroups of Shiga Toxin-Producing Escherichia coli in Cattle Feces

Citation: Noll, L. W., Shridhar, P. B., Dewsbury, D. M., Shi, X. R., Cernicchiaro, N., Renter, D. G., & Nagaraja, T. G. (2015). A Comparison of Culture- and PCR-Based Methods to Detect Six Major Non-O157 Serogroups of Shiga Toxin-Producing Escherichia coli in Cattle Feces. Plos One, 10(8), 12. doi:10.1371/journal.pone.0135446Culture-based methods to detect the six major non-O157 (O26, O45, O103, O111, O121 and O145) Shiga toxin-producing E. coli (STEC) are not well established. Our objectives of this study were to develop a culture-based method to detect the six non-O157 serogroups in cattle feces and compare the detection with a PCR method. Fecal samples (n = 576) were collected in a feedlot from 24 pens during a 12-week period and enriched in E. coli broth at 40 degrees C for 6 h. Enriched samples were subjected to immunomagnetic separation, spread-plated onto a selective chromogenic medium, and initially pooled colonies, and subsequently, single colonies were tested by a multiplex PCR targeting six serogroups and four virulence genes, stx1, stx2, eae, and ehxA (culture method). Fecal suspensions, before and after enrichment, were also tested by a multiplex PCR targeting six serogroups and four virulence genes (PCR method). There was no difference in the proportions of fecal samples that tested positive (74.3 vs. 77.4%) for one or more of the six serogroups by either culture or the PCR method. However, each method detected one or more of the six serogroups in samples that were negative by the other method. Both culture method and PCR indicated that O26, O45, and O103 were the dominant serogroups. Higher proportions (P < 0.05) of fecal samples were positive for O26 (44.4 vs. 22.7%) and O121 (22.9 vs. 2.3%) serogroups by PCR than by the culture method. None of the fecal samples contained more than four serogroups. Only a small proportion of the six serogroups (23/640; 3.6%) isolated carried Shiga toxin genes. The culture method and the PCR method detected all six serogroups in samples negative by the other method, highlighting the importance of subjecting fecal samples to both methods for accurate detection of the six non-O157 STEC in cattle feces

VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory

VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages, 10 figures). Corresponding authors: A.Marinelli and D.Zaboro

Impacts of dietary forage and crude protein levels on the shedding of Escherichia coli O157:H7 and Listeria in dairy cattle feces

Shedding of Escherichia coli O157:H7 and Listeria monocytogenes in ruminant manure is well reported. However, the influence of dietary manipulation on the shedding of the pathogens is not well understood. This study was conducted to improve the understanding of the relationship between dietary feed composition and pathogen shedding in dairy feces, particularly E. coli O157:H7 and L. monocytogenes. Twelve cows were randomly assigned to a 2 × 2 factorial arrangement of 2 dietary forage levels: low forage (37.4% of dry matter [DM]) vs. high forage (HF, 53.3% of DM) and two dietary crude protein (CP) levels: low protein (LP, 15.2% of DM) vs. high protein (HP, 18.5% of DM) in a 4 × 4 replicated Latin square design with four periods each including 15 d adaptation and 3 d sample collection. In CP treatments, significantly low concentrations of L. monocytogenes were observed from cows fed the HP (0.9-1.6 log10 cfu/g) compared to the LP diet (1.3–2.1 log10 cfu/g). Significant interaction effect was observed between dietary forage and crude protein on the presence of E. coli O157:H7 (P < 0.05) but not on L. monocytogenes. On average, the highest E. coli O157:H7 concentration (6.5 log10 cfu/g of feces) was observed from the HF and HP diet and the lowest concentration was 6.2 log10cfu/g from the HF and LP diet. The average L. monocytogenes shedding was within the range of 1.8 to 2.4 log 10cfu/g among the treatments. The study showed that diet has an influence on the shedding of pathogenic bacteria in dairy excreta

Psychometric Properties and Correlates of Precarious Manhood Beliefs in 62 Nations

Precarious manhood beliefs portray manhood, relative to womanhood, as a social status that is hard to earn, easy to lose, and proven via public action. Here, we present cross-cultural data on a brief measure of precarious manhood beliefs (the Precarious Manhood Beliefs scale [PMB]) that covaries meaningfully with other cross-culturally validated gender ideologies and with country-level indices of gender equality and human development. Using data from university samples in 62 countries across 13 world regions (N = 33,417), we demonstrate: (1) the psychometric isomorphism of the PMB (i.e., its comparability in meaning and statistical properties across the individual and country levels); (2) the PMB’s distinctness from, and associations with, ambivalent sexism and ambivalence toward men; and (3) associations of the PMB with nation-level gender equality and human development. Findings are discussed in terms of their statistical and theoretical implications for understanding widely-held beliefs about the precariousness of the male gender role

Prevalence and Serovars of \u3ci\u3eSalmonella\u3c/i\u3e in the Feces of Free-Ranging White-Tailed Deer (\u3ci\u3eOdocoileus virginianus\u3c/i\u3e) in Nebraska

To determine the prevalence and serovars of Salmonella in free-ranging deer, we cultured feces from white-tailed deer (Odocoileus virginianus) harvested by hunters during a regular firearm season in southeastern Nebraska (USA). We recovered Salmonella from 5 (1%; 95% confidence interval: 0.37– 2.20%) of 500 samples and identified four different Salmonella enterica serovars [Litchfield (1), Dessau (1), Infantis (2), and Enteritidis (1)]. Although the prevalence of Salmonella in free-ranging deer appears to be low, the serovars recovered are known to be pathogenic to humans and animals

Comparison data of a two-target real-time PCR assay with and without an internal control in detecting Salmonella enterica from cattle lymph nodes

A real-time PCR (qPCR) assay targeting on invA and pagC genes was developed and validated for the detection and quantification of Salmonella enterica strains (Bai et al., 2018) [1]. A host gene, normally an endogenous housekeeping gene (Beer-Davidson et al., 2018; Poon et al., 2004) [2,3], or an irrelevant exogenous gene (Cheng et al., 2015; Sedlak et al., 2014) [4,5] has been widely used as an internal control to monitor nucleic acid extraction efficiencies and potential PCR inhibitions in PCR-based detection assays. An endogenous internal control designed based on the 18S rRNA gene was used in the above-mentioned qPCR assay. This 18S rRNA internal control amplifies the target gene in multiple species including bovine, swine, ovine, caprine and cervine. Data was generated by the duplex qPCR assay on 138 enriched cattle lymph node samples without the internal control, and compared with data on the same samples tested by the triplex qPCR assay that has the 18S rRNA gene as internal control. Threshold cycle (Ct) data for the duplex and the triplex qPCR on the 138 samples were similar, and are presented in this brief report. Keywords: Real-time PCR, Threshold cycle, Internal control, Salmonella, Foodborne pathogen, Lymph nod