Listeria monocytogenes at the human–wildlife interface: black bears (Ursus americanus) as potential vehicles for Listeria

Listeria monocytogenes is the causative agent of the foodborne illness listeriosis, which can result in severe symptoms and death in susceptible humans and other animals. L. monocytogenes is ubiquitous in the environment and isolates from food and food processing, and clinical sources have been extensively characterized. However, limited information is available on L. monocytogenes from wildlife, especially from urban or suburban settings. As urban and suburban areas are expanding worldwide, humans are increasingly encroaching into wildlife habitats, enhancing the frequency of human–wildlife contacts and associated pathogen transfer events. We investigated the prevalence and characteristics of L. monocytogenes in 231 wild black bear capture events between 2014 and 2017 in urban and suburban sites in North Carolina, Georgia, Virginia and United States, with samples derived from 183 different bears. Of the 231 captures, 105 (45%) yielded L. monocytogenes either alone or together with other Listeria. Analysis of 501 samples, primarily faeces, rectal and nasal swabs for Listeria spp., yielded 777 isolates, of which 537 (70%) were L. monocytogenes. Most L. monocytogenes isolates exhibited serotypes commonly associated with human disease: serotype 1/2a or 3a (57%), followed by the serotype 4b complex (33%). Interestingly, approximately 50% of the serotype 4b isolates had the IVb-v1 profile, associated with emerging clones of L. monocytogenes. Thus, black bears may serve as novel vehicles for L. monocytogenes, including potentially emerging clones. Our results have significant public health implications as they suggest that the ursine host may preferentially select for L. monocytogenes of clinically relevant lineages over the diverse listerial populations in the environment. These findings also help to elucidate the ecology of L. monocytogenes and highlight the public health significance of the human–wildlife interface.     

Twenty-four-hour blood pressure control: an intraarterial review.

Intraarterial blood pressure monitoring has shown the circadian rhythm of blood pressure control. Blood pressures tend to be highest in the morning before falling gradually during the day to a nadir at 3:00 a.m. There is a slight rise in the late afternoon that may correspond to patients' attendance at hospital for calibration of the equipment. There is a small rise in the blood pressure before awakening, and after arousal there is a rise in blood pressure to the peak level of the morning. In this article, we examine the effect of a variety of antihypertensive agents on this rhythm. In general, beta-adrenoceptor blockers appear to have less effect on nocturnal blood pressure and surge in pressure after arousal, while vasodilators, particularly alpha-adrenoceptor blockers, have a pronounced effect. These findings indicate that the rise in blood pressure before awakening and the rapid rise upon arousal appear to be due to increased alpha-adrenoceptor activity.     

Evaluation of microsomes isolated from fresh and frozen myotomal tissue of Atlantic cod (Gadus morhua)

Microsomes were isolated from fresh and frozen myotomal tissue of Atlantic cod by two procedures. Electron microscopy revealed one method to yield microsomes containing greater quantities of myofibrillar debris than the other and this was reflected as reduced 5'-nucleotidase, acid phosphatase and succinate dehydrogenase marker enzyme activity. Overnight freezing of myotomal tissue did not affect the marker enzyme activity of microsomes isolated by either procedure. Morphological changes were observed among microsomes prepared from myotomal tissue retained for 8 weeks at -30 degrees C. Accordingly, 5'-nucleotidase was marginally elevated and acid phosphatase and succinate dehydrogenase activity reduced in comparison to fresh microsome preparations.     

A selective medium for enumeration and recovery of Pseudomonas cepacia biotypes from soil

TB-T medium provides a high degree of selectivity for and detection of Pseudomonas cepacia biotypes upon initial plating from soil. TB-T medium consists of a basal medium with glucose as the sole carbon source and asparagine as the sole nitrogen source. The selectivity of TB-T medium is based on the combination of trypan blue (TB) and tetracycline (T) (pH 5.5). On TB-T medium, 216 of 300 isolates (72%) from five different soil types were identified as P. cepacia. The remaining 28% were facultative organisms that could be separated readily from P. cepacia by anaerobic glucose fermentation and by their inability to grow at 41 degrees C. Molds were controlled on low soil dilutions by adding crystal violet, nystatin, or both. Elimination of either ingredient or elevation of the pH to 7.5 resulted in a pronounced loss of selectivity. The efficiency of recovery varied considerably among P. cepacia strains but was high enough for some strains (76 to 86%) to permit quantitative studies. TB-T medium combines a defined formulation with high selectivity and allows recovery of P. cepacia biotypes from low soil dilutions (10(1) to 10(3)).     

Combinatorial synthesis of CCR5 antagonists

Herein we report the preparation of a combinatorial library of compounds with potent CCR5 binding affinity. The library design was aided by SAR generated in a traditional medicinal chemistry effort. Compounds with novel combinations of subunits were discovered that have high binding affinity for the CCR5 receptor. A potent CCR5 antagonist from the library, compound 11 was found to have moderate anti-HIV-1 activity.