Absolute quantification of priority bacteria in aquaculture using digital PCR.

Modern aquaculture systems are designed for intensive rearing of fish or other species. Both land-based and offshore systems typically contain high loads of biomass and the water quality in these systems is of paramount importance for fish health and production. Microorganisms play a crucial role in removal of organic matter and nitrogen-recycling, production of toxic hydrogen sulfide (H2S), and can affect fish health directly if pathogenic for fish or exerting probiotic properties. Methods currently used in aquaculture for monitoring certain bacteria species numbers still have typically low precision, specificity, sensitivity and are time-consuming. Here, we demonstrate the use of Digital PCR as a powerful tool for absolute quantification of sulfate-reducing bacteria (SRB) and major pathogens in salmon aquaculture, Moritella viscosa, Yersinia ruckeri and Flavobacterium psychrophilum. In addition, an assay for quantification of Listeria monocytogenes, which is a human pathogen bacterium and relevant target associated with salmonid cultivation in recirculating systems and salmon processing, has been assessed. Sudden mass mortality incidents caused by H2S produced by SRB have become of major concern in closed aquaculture systems. An ultra-sensitive assay for quantification of SRB has been established using Desulfovibrio desulfuricans as reference strain. The use of TaqMan® probe technology allowed for the development of multi-plex assays capable of simultaneous quantification of these aquaculture priority bacteria. In single-plex assays, limit of detection was found to be at around 20 fg DNA for M. viscosa, Y. ruckeri and F. psychrophilum, and as low as 2 fg DNA for L. monocytogenes and D. desulfuricans.

Evaluation of soluble fentanyl microneedles for loco-regional anti-nociceptive activity.

The use of opioids for treating acute and chronic pain condition is a common clinical practice. When delivered systemically, the analgesic activity is mediated through the central pathway, which although effective, leads to various adverse effects such as dependence, abuse and respiratory depression. Fentanyl is an opioid analgesic that is available as injection and transdermal patch products for the management of acute and chronic pain. These products require stringent regulatory controls and label warnings on disposal due to the abuse potential associated. This research project evaluated the regional antinociceptive efficacy of fentanyl delivered from soluble microneedles. The microneedle patches were formulated with relatively less drug loading as compared to patches intended for systemic delivery and were tested for their antinociceptive activity in rats by measuring the paw withdrawal latency when exposed to a thermal stimulus. The results indicate that regional delivery of fentanyl mediated through soluble microneedles provides an effective antinociceptive activity. The onset of analgesic activity was faster with microneedle patch (0.5 h) when compared to the adhesive dermal patch (6 h). This study thus demonstrates the effectiveness of microneedle mediated pain management for immediate pain relief.