Extensive Evaluation of a Method for Quantitative Measurement of Aflatoxins B1 and M1 in Animal Urine Using High-Performance Liquid Chromatography with Fluorescence Detection.

BACKGROUND: Aflatoxins (AFs) are common feed contaminants and are one of the common causes of toxin-related pet food poisoning and recalls. OBJECTIVE: Currently, there are no validated methods for the detection and quantitation of AFs in biological matrices to diagnose AF exposure in live animals. Following a successful intra-laboratory method development to quantify AFB1 and AFM1 in animal urine by HPLC with fluorescence detection (HPLC-FLD), the present study was conducted to extensively evaluate the method performance in an unbiased manner using blinded samples. METHODS: The evaluation included two stages. First, the performance was verified in the method-originating laboratory in a single-laboratory blinded method test (BMT-S) trial followed by a multi-laboratory blinded method test (BMT-M) trial. RESULTS: In both trials, accuracy, repeatability, and reproducibility were satisfactory confirming the relatively good ruggedness and robustness of the method and ensuring that it will perform as expected if used by other laboratories in the future. CONCLUSIONS: We extensively evaluated the performance of a quantitative method to detect AFB1 and AFM1 in animal urine by HPLC-FLD by two different laboratories in two separate BMT-S and BMT-M trials. Both BMT results demonstrated the satisfactory accuracy and precision of the method. It is now available to be adopted by other diagnostic laboratories for purposes of diagnosing AF intoxication in animals. HIGHLIGHTS: A simple urine-based diagnostic test method using HPLC-FLD that originated in a single laboratory now has passed a multi-laboratory evaluation and is now available to be shared with other diagnostic laboratories for purposes of diagnosing AF intoxication in animals so better treatment can be rendered.

Non-carbapenemase producing carbapenem-resistant Klebsiella pneumoniae isolated from the urinary tract of a dog.

Objective: Carbapenems are broad-spectrum ß-lactams with excellent activity against multidrug-resistant (MDR) Enterobacterales. Unfortunately, resistance to carbapenems within this bacterial family, known as carbapenem-resistant Enterobacterales (CRE), occurs and challenges the ability to treat difficult MDR infections. Although the impact of carbapenem-resistance has been greatest in human medicine, reports in the veterinary literature are increasing especially as national veterinary antimicrobial resistance surveillance programs are now in place. In this brief communication, we report the isolation of a non-carbapenemase-producing, carbapenem-resistant Klebsiella pneumoniae from the urine of a dog, discuss the likely mechanism of resistance, and wider implications. Animal: Canine. Procedure: Whole genome sequencing and phenotypic antimicrobial susceptibility testing was performed on a K. pneumoniae isolated from the urine of a dog. Results: Antimicrobial susceptibility testing identified phenotypic resistance to imipenem and meropenem. Phenotypic detection of carbapenemase production was negative. Whole genome sequencing identified efflux pump genes associated with carbapenem resistance and point mutations in membrane porin genes. No carbapenemase gene was identified. Conclusion: Phenotypic antimicrobial susceptibility testing identified the K. pneumoniae as a non-carbapenemase producing carbapenem-resistant organism with the proposed genotypic mechanism including alteration of efflux pumps and membrane porin activity and/or expression. Clinical significance: Currently, there is limited use of carbapenem antimicrobial drugs in veterinary medicine, and practitioners may be unfamiliar or unaware of this type of resistance, its significance on routine antimicrobial susceptibility test reports, and implications for antimicrobial therapy and public health. Carbapenem-resistant Enterobacterales are infrequently isolated from companion animals; however, due to increasing adoption of advanced medical and surgical interventions, they may become more prevalent.

Objectif: Les carbapénèmes sont des ß-lactamines à large spectre avec une excellente activité contre les Enterobacterales multirésistantes (MDR). Malheureusement, la résistance aux carbapénèmes au sein de cette famille bactérienne, connue sous le nom d'Enterobacterales résistantes aux carbapénèmes (CRE), se produit et remet en question la capacité de traiter les infections MDR difficiles. Bien que l'impact de la résistance aux carbapénèmes ait été plus important en médecine humaine, les rapports dans la littérature vétérinaire se multiplient, d'autant plus que des programmes nationaux de surveillance de la résistance aux antimicrobiens vétérinaires sont désormais en place. Dans cette brève communication, nous rapportons l'isolement d'une Klebsiella pneumoniae non-productrice de carbapénémase et résistante aux carbapénèmes à partir de l'urine d'un chien, discutons du mécanisme probable de résistance et des implications plus larges. Animal: Canin. Procédure: Le séquençage du génome entier et les tests de sensibilité phénotypique aux antimicrobiens ont été effectués sur un isolat de K. pneumoniae provenant de l'urine d'un chien. Résultats: Les tests de sensibilité aux antimicrobiens ont identifié une résistance phénotypique à l'imipénème et au méropénème. La détection phénotypique de production de carbapénèmase était négative. Le séquençage du génome entier a identifié des gènes de pompe à efflux associés à la résistance aux carbapénèmes et à des mutations ponctuelles dans les gènes des porines membranaires. Aucun gène de carbapénémase n'a été identifié. Conclusion: Les tests de sensibilité phénotypique aux antimicrobiens ont identifié cet isolat de K. pneumoniae comme un organisme résistant aux carbapénèmes ne produisant pas de carbapénémase avec le mécanisme génotypique proposé, y compris l'altération des pompes à efflux et l'activité et/ou l'expression de porines membranaires. Signification clinique: Actuellement, l'utilisation des médicaments antimicrobiens à base de carbapénème en médecine vétérinaire est limitée, et les praticiens peuvent ne pas être familiers ou ne pas être au fait de ce type de résistance, de son importance dans les rapports de routine sur les tests de sensibilité aux antimicrobiens et de ses implications pour la thérapie antimicrobienne et la santé publique. Les Enterobacterales résistantes aux carbapénèmes sont rarement isolées des animaux de compagnie; cependant, en raison de l'adoption croissante d'interventions médicales et chirurgicales avancées, elles peuvent devenir plus répandues.(Traduit par Dr Serge Messier).

Multi-laboratory evaluation of the Illumina iSeq platform for whole genome sequencing of Salmonella, Escherichia coli and Listeria.

There is a growing need for public health and veterinary laboratories to perform whole genome sequencing (WGS) for monitoring antimicrobial resistance (AMR) and protecting the safety of people and animals. With the availability of smaller and more affordable sequencing platforms coupled with well-defined bioinformatic protocols, the technological capability to incorporate this technique for real-time surveillance and genomic epidemiology has greatly expanded. There is a need, however, to ensure that data are of high quality. The goal of this study was to assess the utility of a small benchtop sequencing platform using a multi-laboratory verification approach. Thirteen laboratories were provided the same equipment, reagents, protocols and bacterial reference strains. The Illumina DNA Prep and Nextera XT library preparation kits were compared, and 2×150 bp iSeq i100 chemistry was used for sequencing. Analyses comparing the sequences produced from this study with closed genomes from the provided strains were performed using open-source programs. A detailed, step-by-step protocol is publicly available via protocols.io (https://www.protocols.io/view/iseq-bacterial-wgs-protocol-bij8kcrw). The throughput for this method is approximately 4-6 bacterial isolates per sequencing run (20-26 Mb total load). The Illumina DNA Prep library preparation kit produced high-quality assemblies and nearly complete AMR gene annotations. The Prep method produced more consistent coverage compared to XT, and when coverage benchmarks were met, nearly all AMR, virulence and subtyping gene targets were correctly identified. Because it reduces the technical and financial barriers to generating WGS data, the iSeq platform is a viable option for small laboratories interested in genomic surveillance of microbial pathogens.

Interlaboratory comparison of SARS-CoV2 molecular detection assays in use by U.S. veterinary diagnostic laboratories.

The continued search for intermediate hosts and potential reservoirs for SARS-CoV2 makes it clear that animal surveillance is critical in outbreak response and prevention. Real-time RT-PCR assays for SARS-CoV2 detection can easily be adapted to different host species. U.S. veterinary diagnostic laboratories have used the CDC assays or other national reference laboratory methods to test animal samples. However, these methods have only been evaluated using internal validation protocols. To help the laboratories evaluate their SARS-CoV2 test methods, an interlaboratory comparison (ILC) was performed in collaboration with multiple organizations. Forty-four sets of 19 blind-coded RNA samples in Tris-EDTA (TE) buffer or PrimeStore transport medium were shipped to 42 laboratories. Results were analyzed according to the principles of the International Organization for Standardization (ISO) 16140-2:2016 standard. Qualitative assessment of PrimeStore samples revealed that, in approximately two-thirds of the laboratories, the limit of detection with a probability of 0.95 (LOD95) for detecting the RNA was ≤20 copies per PCR reaction, close to the theoretical LOD of 3 copies per reaction. This level of sensitivity is not expected in clinical samples because of additional factors, such as sample collection, transport, and extraction of RNA from the clinical matrix. Quantitative assessment of Ct values indicated that reproducibility standard deviations for testing the RNA with assays reported as N1 were slightly lower than those for N2, and they were higher for the RNA in PrimeStore medium than those in TE buffer. Analyst experience and the use of either a singleplex or multiplex PCR also affected the quantitative ILC test results.

Presumed Choline Chloride Toxicosis in Cats With Positive Ethylene Glycol Tests After Consuming a Recalled Cat Food.

Four previously healthy adult domestic shorthair cats (2 male, 2 female) from one household developed acute vomiting and ataxia less than 12 hours after consuming a commercial canned cat food. Blood work abnormalities included mild hyperglycemia with increased alanine aminotransferase (n = 1) and decreased blood urea nitrogen (n = 2). The veterinarian conducted whole blood ethylene glycol (EG) tests, which were positive for all cats. There were no known EG exposures. All cats were treated for suspected EG toxicosis and fully recovered after 48 hours. Separately from the cats' case, the same food was voluntarily recalled by the manufacturer 5 days later due to a higher-than-formulated amount of choline chloride added to the food. The 4 cats' canned cat food was tested for choline, choline chloride, EG, diethylene glycol, and propylene glycol to look for causes of the positive whole blood EG test. The cat food contained an average of 165,300 ppm (165,300 mg/kg) choline and 221,600 ppm (221,600 mg/kg) choline chloride on a dry matter basis, which is at least 65 times the recommended choline amount for adult cats. No glycols were detected. This case documents suspected choline toxicosis in cats after consuming a commercial canned cat food with a higher-than-formulated amount of choline chloride, and it suggests that choline toxicosis may cause a positive result on some EG whole blood tests. Choline toxicosis could be a possible differential diagnosis when a cat has a positive EG test and no known exposure to antifreeze.

Development of UHPLC/Q-TOF Analysis Method to Screen Glycerin for Direct Detection of Process Contaminants 3-Monochloropropane-1,2-diol Esters (3-MCPDEs) and Glycidyl Esters (GEs).

The U.S. Food and Drug Administration's (FDA's) Center for Veterinary Medicine (CVM) has been investigating reports of pets becoming ill after consuming jerky pet treats since 2007. Renal failure accounted for 30% of reported cases. Jerky pet treats contain glycerin, which can be made from vegetable oil or as a byproduct of biodiesel production. Glycidyl esters (GEs) and 3-monochloropropanediol esters (3-MCPDEs) are food contaminants that can form in glycerin during the refining process. 3-MCPDEs and GEs pose food safety concerns, as they can release free 3-MCPD and glycidol in vivo. Evidence from studies in animals shows that 3-MCPDEs are potential toxins with kidneys as their main target. As renal failure accounted for 30% of reported pet illnesses after the consumption of jerky pet treats containing glycerin, there is a need to develop a screening method to detect 3-MCPDEs and GEs in glycerin. We describe the development of an ultra-high-pressure liquid chromatography/quadrupole time-of-flight (UHPLC/Q-TOF) method for screening glycerin for MCPDEs and GEs. Glycerin was extracted and directly analyzed without a solid-phase extraction procedure. An exact mass database, developed in-house, of MCPDEs and GEs formed with common fatty acids was used in the screening.

Pet Food-Associated Dietary Exogenous Thyrotoxicosis: Retrospective Study (2016-2018) and Clinical Considerations.

Dietary exogenous thyrotoxicosis is infrequently observed in pet food. A retrospective evaluation of pet food investigations (PFI) was conducted for 17 dogs, including review of medical records, dietary and environmental exposure interviews, food testing, and regulatory action. Five PFIs occurring between 2016 and 2018 involved 7 food products including 2 food types, jerky treats or canned food, made from beef or bison. The dogs' serum thyroid hormone concentrations were evaluated before and after diet change. The foods were tested for active thyroid hormones and hormone precursors using high performance liquid chromatography with inductively coupled plasma mass spectrometry detection. The foods were also examined microscopically. Serum thyroid hormone concentrations of thyroxine (T4) varied depending on the food type consumed. Dogs that consumed dried jerky containing greater T4 concentrations often had increased serum T4 concentrations, whereas dogs that consumed canned products containing greater and 3,4,5- and 3,5,3'-triiodothyronine (T3) concentrations often had decreased serum T4 concentrations. After the diets were changed, serum T4 and T3 concentrations normalized at 1 month. Seven foods containing beef or bison had iodine concentrations greater than 11 mg/kg, and iodine speciation identified variable concentrations of iodide, T4, T3, monoiodotyrosine (MIT), and di-iodotyrosine (DIT). Thyroid gland was found in microscopic sections from one finished food and one ingredient, gullet. FDA performed Health Hazard Evaluations to categorize the exposure risk, and 5 foods were recalled for which the product packaging had not been discarded. Dietary exogenous thyrotoxicosis should be considered in dogs exhibiting clinical signs compatible with hyperthyroidism, especially if consuming beef-based food. A thyroid panel that includes serum iodine, coupled with a thorough feeding history can aid in diagnosis. Thyrotoxicosis is typically reversible after removing the contaminated food from the diet.

A Lateral Flow Method for Aflatoxin B1 in Dry Dog Food: An Inter-Laboratory Trial.

BACKGROUND: Dogs are highly susceptible to aflatoxins, the mycotoxins which most commonly cause acute dog illnesses and deaths following the consumption of contaminated food. OBJECTIVE: In this study, a screening method to detect aflatoxin B1 (AFB1) in dry dog food was further evaluated at the FDA action level of 20 ng/g. A fourth-round multi-laboratory trial was performed. In contrast to the previous work, a different source of dog food was used in the multi-laboratory trial and more participants were involved. METHOD: The tested lateral flow method employs a modified procedure of the "Rosa® AFQ-Fast Test Kit" from Charm Sciences Inc. A total of 60 unfortified blank study samples, 220 study samples fortified at 20 ng/g, and 80 study samples fortified at 9-11 ng/g were prepared by an independent party and analyzed in 10 collaborating laboratories in a blinded manner. RESULTS: The pass rates were 98.3 and 94.5% for unfortified and 20 ng/g fortified study samples, respectively. CONCLUSIONS: The method is suitable for aflatoxin B1 screening at the FDA action level of 20 ng/g in a complex matrix such as dry dog food. HIGHLIGHTS: This work completes extensive method performance evaluation through four rounds of multi-laboratory trials.

Extensive Evaluation via Blinded Testing of an UHPLC-MS/MS Method for Quantitation of Ten Ergot Alkaloids in Rye and Wheat Grains.

BACKGROUND: Ergot alkaloids are mycotoxins produced by the fungus Claviceps, which can contaminate grains and pose a health risk to humans and animals. Validation of an ergot alkaloid method in collaborative projects can be challenging due to instability of analytes, a lack of reliable reference materials, and a fully validated reference method. OBJECTIVE: To extensively evaluate performance of a quantitative UHPLC-MS/MS method to detect ten ergot alkaloids at concentrations between 16 and 500 ng/g in grains. METHOD: The method performance was evaluated in the Blinded Method Test (BMT) exercise, which allowed organizers to successfully address the challenges. Forty completely blinded test samples were prepared in an independent laboratory and shipped to a participating laboratory to analyze on two separate days. RESULTS: Precision, accuracy, and HorRatr values met or exceeded the U.S. Food and Drug Administration recommendations. The design of the BMT exercise provided a high degree of confidence in data and conclusions drawn. CONCLUSIONS: The method performed in a manner as expected, and the method can be used by the laboratory for routine testing of wheat and rye grains. HIGHLIGHTS: BMT of laboratory methods facilitate validation of tests by evaluating performance in an unbiased manner.

New Delhi Metallo-ß-Lactamase-5-Producing Escherichia coli in Companion Animals, United States.

We report isolation of a New Delhi metallo-ß-lactamase-5-producing carbapenem-resistant Escherichia coli sequence type 167 from companion animals in the United States. Reports of carbapenem-resistant Enterobacteriaceae in companion animals are rare. We describe a unique cluster of blaNDM-5-producing E. coli in a veterinary hospital.

Multilaboratory Evaluation of a Lateral Flow Method for Aflatoxin B1 Analysis in Dry Dog Food.

BACKGROUND: Aflatoxins are one of the most heavily regulated mycotoxins in agriculture throughout the world. A variety of tests are used for detection, including rapid methods that are preferred when a large number of samples need to be quickly screened to implement an immediate action. However, a method developed for screening a specific commodity for the presence of mycotoxins requires further validation to demonstrate its suitability for additional matrices. OBJECTIVE: In this study, a study was undertaken to evaluate a rapid screening method for aflatoxin B1 (AFB1) in dry dog food, a product potentially susceptible to aflatoxins contamination. METHOD: This test method employed lateral flow technology using kits obtained from Charm Sciences Inc. Three different sources of dry dog food were tested at the FDA action level of 20 ppb (ng/g) in three trials of a multi-laboratory study by four participants. A total of 80 unfortified blank samples, 270 samples spiked at 20 ppb, and 60 samples spiked below 20 ppb were analyzed. RESULTS: The overall pass rates of 100% for unfortified samples and > 97% for 20 ppb-fortified samples meet the FDA guidance acceptance criteria for a limit test of 10-15% false positives and no more than 5% false negatives. CONCLUSIONS: The method is suitable for screening a large number of dry dog food samples for rapid response. HIGHLIGHTS: Multi-laboratory evaluation of a rapid method for aflatoxin screening in dog food.

Complete Genome Sequence of a Carbapenem-Resistant Escherichia coli Isolate with bla NDM-5 from a Dog in the United States.

The carbapenem resistance gene bla NDM-5 was identified in an Escherichia coli strain isolated from a dog. We report here the complete genome sequence of this E. coli strain; the bla NDM-5 gene was present on a large IncFII multidrug-resistant plasmid. This is the first bla NDM-5-carrying E. coli strain from an animal in the United States.

Effects of dietary taurine level on visual function in European sea bass (Dicentrarchus labrax).

Dietary insufficiencies have been well documented to decrease growth rates and survival (and therefore overall production) in fish aquaculture. By contrast, the effects of dietary insufficiencies on the sensory biology of cultured fish remains largely unstudied. Diets based solely on plant protein sources could have advantages over fish-based diets because of the cost and ecological effects of the latter, but plant proteins lack the amino acid taurine. Adequate levels of taurine are, however, necessary for the development of a fully functional visual system in mammals. As part of ongoing studies to determine the suitability of plant-based diets, we investigated the effects of normal and reduced taurine dietary levels on retinal anatomy and function in European sea bass (Dicentrarchus labrax). We could not demonstrate any effects of dietary taurine level on retinal anatomy, nor the functional properties of luminous sensitivity and temporal resolution (measured as flicker fusion frequency). We did, however, find an effect on spectral sensitivity. The peak of spectral sensitivity of individuals fed a 5% taurine diet was rightward shifted (i.e., towards longer wavelengths) relative to that of fish fed a 0% or 1.5% taurine diet. This difference in in spectral sensitivity was due to a relatively lower level of middle wavelength pigment (maximum absorbance .500 nm) in fish fed a 5% taurine diet. Changes in spectral sensitivity resulting from diets containing different taurine levels are unlikely to be detrimental to fish destined for market, but could be in fishes that are being reared for stock enhancement programs.

Enhancing the one health initiative by using whole genome sequencing to monitor antimicrobial resistance of animal pathogens: Vet-LIRN collaborative project with veterinary diagnostic laboratories in United States and Canada.

BACKGROUND: Antimicrobial resistance (AMR) of bacterial pathogens is an emerging public health threat. This threat extends to pets as it also compromises our ability to treat their infections. Surveillance programs in the United States have traditionally focused on collecting data from food animals, foods, and people. The Veterinary Laboratory Investigation and Response Network (Vet-LIRN), a national network of 45 veterinary diagnostic laboratories, tested the antimicrobial susceptibility of clinically relevant bacterial isolates from animals, with companion animal species represented for the first time in a monitoring program. During 2017, we systematically collected and tested 1968 isolates. To identify genetic determinants associated with AMR and the potential genetic relatedness of animal and human strains, whole genome sequencing (WGS) was performed on 192 isolates: 69 Salmonella enterica (all animal sources), 63 Escherichia coli (dogs), and 60 Staphylococcus pseudintermedius (dogs). RESULTS: We found that most Salmonella isolates (46/69, 67%) had no known resistance genes. Several isolates from both food and companion animals, however, showed genetic relatedness to isolates from humans. For pathogenic E. coli, no resistance genes were identified in 60% (38/63) of the isolates. Diverse resistance patterns were observed, and one of the isolates had predicted resistance to fluoroquinolones and cephalosporins, important antibiotics in human and veterinary medicine. For S. pseudintermedius, we observed a bimodal distribution of resistance genes, with some isolates having a diverse array of resistance mechanisms, including the mecA gene (19/60, 32%). CONCLUSION: The findings from this study highlight the critical importance of veterinary diagnostic laboratory data as part of any national antimicrobial resistance surveillance program. The finding of some highly resistant bacteria from companion animals, and the observation of isolates related to those isolated from humans demonstrates the public health significance of incorporating companion animal data into surveillance systems. Vet-LIRN will continue to build the infrastructure to collect the data necessary to perform surveillance of resistant bacteria as part of fulfilling its mission to advance human and animal health. A One Health approach to AMR surveillance programs is crucial and must include data from humans, animals, and environmental sources to be effective.

Evaluation of a Diagnostic Method to Quantify Aflatoxins B1 and M1 in Animal Liver by High-Performance Liquid Chromatography with Fluorescence Detection.

Background: Aflatoxins (AFs) are secondary metabolites of fungi and are one of the causes of toxin-related pet food recalls. An intralaboratory method was previously developed to quantify aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1) in animal liver by HPLC with fluorescence detection. Objective: The aim of this study was to extensively evaluate the method performance with a single-laboratory blinded method test (BMT-S) and a multilaboratory blinded method test (BMT-M). Methods: Blinded tissue samples were prepared by a third-party laboratory and sent out to participating laboratories for both BMT-S and BMT-M. Results: In both tests, participants analyzed blinded samples prepared by an independent laboratory. In the BMT-S, accuracy ranged between 111 and 154% for AFB1 and 113 and 159% for AFM1 within the quantitation range of 0.1-0.5 ng/g. The HorRat values for repeatability ranged between 0.1 and 0.3 for AFB1 and 0.3 and 0.6 for AFM1. In the BMT-M, the interlaboratory accuracy ranged between 77 and 81% for AFB1 and 83 and 85% for AFM1 within the quantitation range of 0.2-10 ng/g. The HorRat values for reproducibility ranged between 0.4 and 0.7 for AFB1 and 0.4 and 0.9 for AFM1. Both recovery and reproducibility were acceptable. Conclusions: BMT-M evaluation demonstrated that the method was suitable for quantitation of aflatoxins B1 and M1 in animal liver between laboratories. Highlights: The BMT-S and BMT-M results demonstrated that the method is rugged and reproducible among the participating laboratories.

Whole genome sequencing confirms source of pathogens associated with bacterial foodborne illness in pets fed raw pet food.

Reports of raw meat pet food containing zoonotic foodborne bacteria, including Salmonella, Escherichia coli, and Listeria monocytogenes, are increasing. Contaminated raw pet food and biological waste from pets consuming those diets may pose a public health risk. The U.S. Food and Drug Administration Veterinary Laboratory Investigation and Response Network conducted 2 case investigations, involving 3 households with animal illnesses, which included medical record review, dietary and environmental exposure interviews, animal sample testing, and whole genome sequencing (WGS) of bacteria isolated from the pets and the raw pet food. For each case investigation, WGS with core genome multi-locus sequence typing analysis showed that the animal clinical isolates were closely related to one or more raw pet food bacterial isolates. WGS and genomic analysis of paired animal clinical and animal food isolates can confirm suspected outbreaks of animal foodborne illness.

Diet-induced obesity precipitates kidney dysfunction and alters inflammatory mediators in mice treated with Shiga Toxin 2.

Shiga Toxin (Stx)-producing E. coli (STEC) continue to be a prominent cause of foodborne outbreaks of hemorrhagic colitis worldwide, and can result in life-threatening diseases, including hemolytic uremic syndrome (HUS), in susceptible individuals. Obesity-associated immune dysfunction has been shown to be a risk factor for infectious diseases, although few studies have addressed the role of obesity in foodborne diseases. We hypothesized that obesity may affect the development of HUS through an alteration of immune responses and kidney function. We combined diet-induced obese (DIO) and HUS mouse models to look for differences in disease outcome between DIO and wild-type (WT) male and female C57 B l/6 mice. Following multiple intraperitoneal injections with endotoxin-free saline or sublethal doses of purified Stx2, we examined DIO and WT mice for signs of HUS development. DIO mice receiving Stx2 injections lost more body weight, and had significantly higher (p < 0.001) BUN, serum creatinine, and neutrophil counts compared to WT mice or DIO mice receiving saline injections. Lymphocyte counts were significantly (p < 0.05) lower in Stx2-treated obese mice compared to WT mice or saline-treated DIO mice. In addition to increased Stx2-induced kidney dysfunction, DIO mouse kidneys also had significantly increased expression of IL-1α, IL-1ß, IL-6, TNF-α, MCP-1, and KC RNA compared to saline controls (p < 0.05). Serum cytokine levels of IL-6 and KC were also significantly higher in Stx2-treated mice compared to saline controls, but there were no significant differences between the WT and DIO mice. WT and DIO mice treated with Stx2 exhibited significantly higher degrees of kidney tubular dilation and necrosis as well as some signs of tissue repair/regeneration, but did not appear to progress to the full pathology typically associated with human HUS. Although the combined obesity/HUS mouse model did not manifest into HUS symptoms and pathogenesis, these data demonstrate that obesity alters kidney function, inflammatory cells and cytokine production in response to Stx2, and may play a role in HUS severity in a susceptible model of infection.

Pathology and Epidemiology of Oxalate Nephrosis in Cheetahs.

To investigate cases of acute oxalate nephrosis without evidence of ethylene glycol exposure, archived data and tissues from cheetahs ( Acinonyx jubatus) from North America ( n = 297), southern Africa ( n = 257), and France ( n = 40) were evaluated. Renal and gastrointestinal tract lesions were characterized in a subset of animals with ( n = 100) and without ( n = 165) oxalate crystals at death. Crystals were confirmed as calcium oxalate by Raman spectroscopy in 45 of 47 cheetahs tested. Crystals were present in cheetahs from 3.7 months to 15.9 years old. Cheetahs younger than 1.5 years were less likely to have oxalates than older cheetahs ( P = .034), but young cheetahs with oxalates had more oxalate crystals than older cheetahs ( P < .001). Cheetahs with oxalate crystals were more likely to have renal amyloidosis, interstitial nephritis, or colitis and less likely to have glomerular loop thickening or gastritis than those without oxalates. Crystal number was positively associated with renal tubular necrosis ( P ≤ .001), regeneration ( P = .015), and casts ( P ≤ .001) but inversely associated with glomerulosclerosis, renal amyloidosis, and interstitial nephritis. Crystal number was unrelated to the presence or absence of colitis and was lower in southern African than American and European animals ( P = .01). This study found no evidence that coexisting chronic renal disease (amyloidosis, interstitial nephritis, or glomerulosclerosis), veno-occlusive disease, gastritis, or enterocolitis contributed significantly to oxalate nephrosis. Oxalate-related renal disease should be considered as a potential cause of acute renal failure, especially in young captive cheetahs. The role of location, diet, stress, and genetic predisposition in the pathogenesis of oxalate nephrosis in cheetahs warrants further study.

Application of time-of-flight mass spectrometry for screening of crude glycerins for toxic phorbol ester contaminants.

Since 2007, the U.S. Food and Drug Administration (FDA) has received numerous complaints of pet illnesses that may be related to the consumption of jerky pet treats. Many of those treats include glycerin as an ingredient. Glycerin can be made directly from oils such as palm seed oil, but can also be derived from the seed oil of toxic Jatropha plant during biodiesel production. If crude glycerin from biodiesel production from Jatropha curcas is used in the manufacture of animal feed, toxic tigliane diterpene phorbol esters (PEs), namely Jatropha factors (JFs), may be present and could lead to animal illnesses. Considering the numerous uses of glycerin in consumer products there is a need for a rapid method to screen crude glycerin for JF toxins and other PE contaminants. We describe the development of an ultra-high pressure liquid chromatography/quadrupole time of flight (UHPLC/Q-TOF) method for screening crude glycerin for PEs. An exact mass database, developed in-house, of previously identified PEs from Jatropha curcas as well as putative compounds was used to identify possible contaminants.