Genetic Microbial Source Tracking Support QMRA Modeling for a Riverine Wetland Drinking Water Resource.

Riverine wetlands are important natural habitats and contain valuable drinking water resources. The transport of human- and animal-associated fecal pathogens into the surface water bodies poses potential risks to water safety. The aim of this study was to develop a new integrative modeling approach supported by microbial source tracking (MST) markers for quantifying the transport pathways of two important reference pathogens, Cryptosporidium and Giardia, from external (allochthonous) and internal (autochthonous) fecal sources in riverine wetlands considering safe drinking water production. The probabilistic-deterministic model QMRAcatch (v 1.1 python backwater) was modified and extended to account for short-time variations in flow and microbial transport at hourly time steps. As input to the model, we determined the discharge rates, volumes and inundated areas of the backwater channel based on 2-D hydrodynamic flow simulations. To test if we considered all relevant fecal pollution sources and transport pathways, we validated QMRAcatch using measured concentrations of human, ruminant, pig and bird associated MST markers as well as E. coli in a Danube wetland area from 2010 to 2015. For the model validation, we obtained MST marker decay rates in water from the literature, adjusted them within confidence limits, and simulated the MST marker concentrations in the backwater channel, resulting in mean absolute errors of < 0.7 log10 particles/L (Kruskal-Wallis p > 0.05). In the scenarios, we investigated (i) the impact of river discharges into the backwater channel (allochthonous sources), (ii) the resuspension of pathogens from animal fecal deposits in inundated areas, and (iii) the pathogen release from animal fecal deposits after rainfall (autochthonous sources). Autochthonous and allochthonous human and animal sources resulted in mean loads and concentrations of Cryptosporidium and Giardia (oo)cysts in the backwater channel of 3-13 × 109 particles/hour and 0.4-1.2 particles/L during floods and rainfall events, and in required pathogen treatment reductions to achieve safe drinking water of 5.0-6.2 log10. The integrative modeling approach supports the sustainable and proactive drinking water safety management of alluvial backwater areas.

Insights in the regulation of trimetylamine N-oxide production using a comparative biomimetic approach suggest a metabolic switch in hibernating bears.

Experimental studies suggest involvement of trimethylamine N-oxide (TMAO) in the aetiology of cardiometabolic diseases and chronic kidney disease (CKD), in part via metabolism of ingested food. Using a comparative biomimetic approach, we have investigated circulating levels of the gut metabolites betaine, choline, and TMAO in human CKD, across animal species as well as during hibernation in two animal species. Betaine, choline, and TMAO levels were associated with renal function in humans and differed significantly across animal species. Free-ranging brown bears showed a distinct regulation pattern with an increase in betaine (422%) and choline (18%) levels during hibernation, but exhibited undetectable levels of TMAO. Free-ranging brown bears had higher betaine, lower choline, and undetectable TMAO levels compared to captive brown bears. Endogenously produced betaine may protect bears and garden dormice during the vulnerable hibernating period. Carnivorous eating habits are linked to TMAO levels in the animal kingdom. Captivity may alter the microbiota and cause a subsequent increase of TMAO production. Since free-ranging bears seems to turn on a metabolic switch that shunts choline to generate betaine instead of TMAO, characterisation and understanding of such an adaptive switch could hold clues for novel treatment options in burden of lifestyle diseases, such as CKD.

Surgical castration of the male common hippopotamus (Hippopotamus amphibius).

In a prospective, clinical, surgery study we report here for the first time, in detail, on the surgical castration of 10 captive adult male common hippopotami (Hippopotamus amphibius). The successful procedures, a species-specific modification of standard equine castration techniques, provide valuable insight into the spatially dynamic nature of the common hippopotamus testis. The use of ultrasonography to locate the testis before and during the procedures and species-specific positioning during surgery greatly facilitated this distinctive procedure. Additionally, this surgical method provides an important additional tool for captive management of the common hippopotamus. Castration of individual males not only facilitates population control but can potentially also be employed to limit intermale aggression.

Characterization of methicillin-resistant Staphylococcus spp. carrying the mecC gene, isolated from wildlife.

OBJECTIVES: A recently identified mecA homologue, mecC, in methicillin-resistant Staphylococcus aureus (MRSA) has been isolated from humans and different animal hosts. The aim of this study was to determine antimicrobial resistance and provide molecular characterization of MRSA and methicillin-resistant non-Staphylococcus aureus staphylococci (MRnSA) isolated from wildlife that carried the gene mecC. METHODS: Five S. aureus and one coagulase-negative Staphylococcus isolate displaying phenotypic oxacillin resistance, but not recognized with conventional PCR for mecA, were further characterized by a polyphasic approach. The presence of mecC in all isolates was determined using specific PCR. PCR targeting Panton-Valentine leucocidin (PVL) genes of MRSA was performed. MRSA isolates were genotyped by spa typing and multilocus sequence typing. All isolates were genotyped by staphylococcal cassette chromosome mec (SCCmec) typing. 16S rDNA sequence analysis for MRnSA identification was performed. Antimicrobial susceptibility testing was performed for all isolates. RESULTS: All five MRSA isolates contained the mecC gene, were PVL negative, carried SCCmec type XI and belonged to ST130 (where ST stands for sequence type), with spa types t843, t10513 or t3256, or to ST2620, with spa type t4335. The MRnSA isolate, most closely related to Staphylococcus stepanovicii, carried mecA and blaZ genes related to SCCmec XI. MRSA isolates exhibited resistance to the ß-lactams only. CONCLUSIONS: The MRSA isolates described in this study represent the first detection of mecC-positive MRSA in a European otter (Lutra lutra) and a European brown hare (Lepus europaeus). The MRnSA isolate represents the first isolation of MRnSA from a Eurasian lynx (Lynx lynx).