A prebiotic, Celmanax™, decreases Escherichia coli O157:H7 colonization of bovine cells and feed-associated cytotoxicity in vitro

<p>Abstract</p> <p>Background</p> <p><it>Escherichia coli </it>O157:H7 is the most common serovar of enterohemorrhagic <it>E. coli </it>associated with serious human disease outbreaks. Cattle are the main reservoir with <it>E. coli </it>O157:H7 inducing hemorrhagic enteritis in persistent shedding beef cattle, however little is known about how this pathogen affects cattle health. Jejunal Hemorrhage Syndrome (JHS) has unclear etiology but the pathology is similar to that described for <it>E. coli </it>O157:H7 challenged beef cattle suggestive that <it>E. coli </it>O157:H7 could be involved. There are no effective treatments for JHS however new approaches to managing pathogen issues in livestock using prebiotics and probiotics are gaining support. The first objective of the current study was to characterize pathogen colonization in hemorrhaged jejunum of dairy cattle during natural JHS outbreaks. The second objective was to confirm the association of mycotoxigenic fungi in feeds with the development of JHS and also to identify the presence of potential mycotoxins. The third objective was to determine the impact of a prebiotic, Celmanax™, or probiotic, Dairyman's Choice™ paste, on the cytotoxicity associated with feed extracts <it>in vitro</it>. The fourth objective was to determine the impact of a prebiotic or a probiotic on <it>E. coli </it>O157:H7 colonization of mucosal explants and a bovine colonic cell line <it>in vitro</it>. The final objective was to determine if prebiotic and probiotic feed additives could modify the symptoms that preceded JHS losses and the development of new JHS cases.</p> <p>Findings</p> <p>Dairy cattle developed JHS after consuming feed containing several types of mycotoxigenic fungi including <it>Fusarium culmorum</it>, <it>F. poae</it>, <it>F. verticillioides</it>, <it>F. sporotrichioides</it>, <it>Aspergillus</it><it>flavus</it>, <it>Penicillium roqueforti, P. crustosum, P. paneum </it>and <it>P. citrinum</it>. Mixtures of Shiga toxin - producing <it>Escherichia coli </it>(STEC) colonized the mucosa in the hemorrhaged tissues of the cattle and no other pathogen was identified. The STECs expressed Stx1 and Stx2, but more significantly, Stxs were also present in the blood clot blocking the jejunum. Mycotoxin analysis of the corn crop confirmed the presence of fumonisin, NIV, ZEAR, DON, 15-ADON, 3-ADON, NEO, DAS, HT-2 and T-2. Feed extracts were toxic to enterocytes and 0.1% Celmanax™ removed the cytotoxicity <it>in vitro</it>. There was no effect of Dairyman's Choice™ paste on feed-extract activity <it>in vitro</it>. Fumonisin, T-2, ZEAR and DON were toxic to bovine cells and 0.1% Celmanax™ removed the cytotoxicity <it>in vitro</it>. Celmanax™ also directly decreased <it>E. coli </it>O157:H7 colonization of mucosal explants and a colonic cell line in a dose-dependent manner. There was no effect of Dairyman's Choice™ paste on <it>E. coli </it>O157:H7 colonization <it>in vitro</it>. The inclusion of the prebiotic and probiotic in the feed was associated with a decline in disease.</p> <p>Conclusion</p> <p>The current study confirmed an association between mycotoxigenic fungi in the feed and the development of JHS in cattle. This association was further expanded to include mycotoxins in the feed and mixtures of STECs colonizing the severely hemorrhaged tissues. Future studies should examine the extent of involvement of the different STEC in the infection process. The prebiotic, Celmanax™, acted as an anti-adhesive for STEC colonization and a mycotoxin binder <it>in vitro</it>. Future studies should determine the extent of involvement of the prebiotic in altering disease.</p

Baseline microcephaly prevalence in rural Guatemala: implications for neonatal screening for congenital Zika virus infection

Background: Microcephaly is the result of disturbance in early brain development and has various causes. Zika was identified in Central America in early 2015. Establishing baseline microcephaly rates in areas affected by Zika is important for the assessment of the burden and contribution of Zika to microcephaly in low-resource settings. Methods: We undertook a retrospective review of records from a community wellness programme in rural Guatemala where trained community health workers obtained data on weight, length, and head circumference for infants aged 0 to 13 days, enrolled in the programme between August 1, 2014, and March 31, 2016. We estimated gestational age using a Z-score of zero for length on the modified Fenton growth curve. Z-scores for head circumference and weight, adjusted for gestational age and sex, were then calculated. We used univariate logistic regression to test associations between microcephaly and low weight (Z ≤−1), small size for gestational age (weight below 10th percentile for gestational age), and sex. We analysed head circumference Z-scores and microcephaly for changes over time using birth month as well as multiple time-breaks (we compared infants born before versus after April 30, 2015; October 31, 2015; and January 31, 2016) with Student t-tests, and logistic and linear regression. Findings: We included 296 infants: mean head circumference Z-score was −0·68 (95% CI −0·78 to −0·58). 20 infants (6·8%) had a head circumference Z-score ≤–2 and were considered to have microcephaly, giving a microcephaly prevalence of 676 per 10 000 livebirths. One infant (0·3%) had a head circumference Z-score ≤–3. Weight ≤–1 SD (OR 4·59 (1·69–12·41, p=0·003) and small for gestational age (6·65, 1·88–23·55, p=0·003) were associated with microcephaly. Sex was not significantly associated with microcephaly. Birth month and time-breaks were not associated with microcephaly nor with head circumference Z score. Interpretation: Baseline neonatal microcephaly present in this rural Guatemalan community before and during Guatemala's early Zika epidemic is more than 100 and 300 times higher than baseline rates reported before the Zika virus epidemic in Puerto Rico and Brazil, respectively. Increased microcephaly rate associated with Zika epidemics in other countries was not detectable in our study population, probably because data were collected early in the Zika epidemic. High baseline microcephaly rates have important implications for neonatal screening programmes to identify infants congenitally infected with Zika in low-income countries. Funding: The Center for Global Health at the University of Colorado and the Jose Fernando Bolanos Menendez Foundation provided funding for the wellness programme