Highly Pathogenic Avian Influenza A(H5N1) Clade 2.3.4.4b Virus Infection in Domestic Dairy Cattle and Cats, United States, 2024.

We report highly pathogenic avian influenza A(H5N1) virus in dairy cattle and cats in Kansas and Texas, United States, which reflects the continued spread of clade 2.3.4.4b viruses that entered the country in late 2021. Infected cattle experienced nonspecific illness, reduced feed intake and rumination, and an abrupt drop in milk production, but fatal systemic influenza infection developed in domestic cats fed raw (unpasteurized) colostrum and milk from affected cows. Cow-to-cow transmission appears to have occurred because infections were observed in cattle on Michigan, Idaho, and Ohio farms where avian influenza virus-infected cows were transported. Although the US Food and Drug Administration has indicated the commercial milk supply remains safe, the detection of influenza virus in unpasteurized bovine milk is a concern because of potential cross-species transmission. Continued surveillance of highly pathogenic avian influenza viruses in domestic production animals is needed to prevent cross-species and mammal-to-mammal transmission.

Sialic Acid Receptor Specificity in Mammary Gland of Dairy Cattle Infected with Highly Pathogenic Avian Influenza A(H5N1) Virus.

In March 2024, the US Department of Agriculture's Animal and Plant Health Inspection Service reported detection of highly pathogenic avian influenza (HPAI) A(H5N1) virus in dairy cattle in the United States for the first time. One factor that determines susceptibility to HPAI H5N1 infection is the presence of specific virus receptors on host cells; however, little is known about the distribution of the sialic acid (SA) receptors in dairy cattle, particularly in mammary glands. We compared the distribution of SA receptors in the respiratory tract and mammary gland of dairy cattle naturally infected with HPAI H5N1. The respiratory and mammary glands of HPAI H5N1-infected dairy cattle are rich in SA, particularly avian influenza virus-specific SA α2,3-gal. Mammary gland tissues co-stained with sialic acids and influenza A virus nucleoprotein showed predominant co-localization with the virus and SA α2,3-gal. HPAI H5N1 exhibited epitheliotropism within the mammary gland, and we observed rare immunolabeling within macrophages.

Small Noncoding RNA CjNC110 Influences Motility, Autoagglutination, AI-2 Localization, Hydrogen Peroxide Sensitivity, and Chicken Colonization in Campylobacter jejuni.

Small noncoding RNAs (ncRNAs) are involved in many important physiological functions in pathogenic microorganisms. Previous studies have identified the presence of noncoding RNAs in the major zoonotic pathogen Campylobacter jejuni; however, few have been functionally characterized to date. CjNC110 is a conserved ncRNA in C. jejuni, located downstream of the luxS gene, which is responsible for the production of the quorum sensing molecule autoinducer-2 (AI-2). In this study, we utilized strand specific high-throughput RNAseq to identify potential targets or interactive partners of CjNC110 in a sheep abortion clone of C. jejuni These data were then utilized to focus further phenotypic evaluation of the role of CjNC110 in motility, autoagglutination, quorum sensing, hydrogen peroxide sensitivity, and chicken colonization in C. jejuni Inactivation of the CjNC110 ncRNA led to a statistically significant decrease in autoagglutination ability as well as increased motility and hydrogen peroxide sensitivity compared to the wild-type. Extracellular AI-2 detection was decreased in ΔCjNC110; however, intracellular AI-2 accumulation was significantly increased, suggesting a key role of CjNC110 in modulating the transport of AI-2. Notably, ΔCjNC110 also showed a decreased ability to colonize chickens. Complementation of CjNC110 restored all phenotypic changes back to wild-type levels. The collective results of the phenotypic and transcriptomic changes observed in our data provide valuable insights into the pathobiology of C. jejuni sheep abortion clone and strongly suggest that CjNC110 plays an important role in the regulation of energy taxis, flagellar glycosylation, cellular communication via quorum sensing, oxidative stress tolerance, and chicken colonization in this important zoonotic pathogen.

Role of metAB in Methionine Metabolism and Optimal Chicken Colonization in Campylobacter jejuni.

Campylobacter jejuni is a zoonotic pathogen and is one of the leading causes of human gastroenteritis worldwide. C. jejuni IA3902 (representative of the sheep abortion clone) is genetically similar to C. jejuni W7 (representative of strain type NCTC 11168); however, there are significant differences in the ability of luxS mutants of these strains to colonize chickens. LuxS is essential for the activated methyl cycle and generates homocysteine for conversion to l-methionine. Comparative genomics identified differential distribution of the genes metA and metB, which function to convert homoserine for downstream production of l-methionine, between IA3902 and W7, which could enable a secondary pathway for l-methionine biosynthesis in a W7 ΔluxS but not in an IA3902 ΔluxS strain. To test the hypothesis that the genes metA and metB contribute to l-methionine production and chicken colonization by Campylobacter, we constructed two mutants for phenotypic comparison, the W7 ΔmetAB ΔluxS and IA3902 ΔluxS::metAB mutants. Quantitative reverse transcription-PCR and tandem mass spectrometry protein analysis were used to validate MetAB transcription and translation as present in the IA3902 ΔluxS::metAB mutant and absent in the W7 ΔmetAB ΔluxS mutant. Time-resolved fluorescence resonance energy transfer fluorescence assays demonstrated that l-methionine and S-adenosyl methionine concentrations decreased in the W7 ΔmetAB ΔluxS mutant and increased in the IA3902 ΔluxS::metAB mutant. Assessment of chicken colonization revealed that the IA3902 ΔluxS::metAB strain partially rescued the colonization defect of the IA3902 ΔluxS strain, while the W7 ΔmetAB ΔluxS strain showed significantly decreased colonization compared to that of the wild-type and the W7 ΔluxS strain. These results indicate that the ability to maintain l-methionine production in vivo, conferred by metA and metB in the absence of luxS, is critical for normal chicken colonization by C. jejuni.

The Rho-Independent Transcription Terminator for the porA Gene Enhances Expression of the Major Outer Membrane Protein and Campylobacter jejuni Virulence in Abortion Induction.

Campylobacter jejuni is a leading cause of foodborne illnesses worldwide. Its porA gene encodes the major outer membrane protein (MOMP) that is abundantly expressed and has important physiological functions, including a key role in systemic infection and abortion induction in pregnant animals. Despite the importance of porA in C. jejuni pathogenesis, mechanisms modulating its expression levels remain elusive. At the 3' end of the porA transcript, there is a Rho-independent transcription terminator (named T porA in this study). Whether T porA affects the expression and function of MOMP remains unknown and is investigated in this study. Green fluorescent protein (GFP) fusion constructs with the porA promoter at the 5' end and an intact T porA or no T porA at the 3' end of the gfp coding sequence revealed that both the transcript level of gfp and its fluorescence signals were more than 2-fold higher in the construct with T porA than in the one without T porA Real-time quantitative PCR (qRT-PCR) analysis of the porA mRNA and immunoblot detection of MOMP in C. jejuni showed that disruption of T porA significantly reduced the porA transcript level and the expression of MOMP. An mRNA decay assay demonstrated that disruption of T porA resulted in a shortened transcript half-life of the upstream gfp or porA gene, indicating that T porA enhances mRNA stability. In the guinea pig model, the C. jejuni construct with an interrupted T porA was significantly attenuated in abortion induction. Together, these results indicate that T porA enhances the expression level of MOMP by stabilizing its mRNA and influences the virulence of C. jejuni.

High Prevalence of Fluoroquinolone-Resistant Campylobacter Bacteria in Sheep and Increased Campylobacter Counts in the Bile and Gallbladders of Sheep Medicated with Tetracycline in Feed.

Campylobacter is a major foodborne pathogen in humans and a significant cause of abortion in sheep. Although ruminants are increasingly recognized as important reservoirs for Campylobacter species, limited information is available about the molecular epidemiology and antimicrobial resistance (AMR) profiles of sheep Campylobacter Here, we describe a two-trial study that examined Campylobacter profiles in sheep and determined whether in-feed tetracycline (TET) influenced the distribution and AMR profiles of Campylobacter Each trial involved 80 commercial sheep naturally infected with Campylobacter: 40 of these sheep were medicated with tetracycline in feed, while the other 40 received feed without antibiotics. Fecal and bile samples were collected for the isolation of Campylobacter The bacterial isolates were analyzed for antimicrobial susceptibility and genotypes. The results revealed that 87.0% and 61.3% of the fecal and bile samples were positive for Campylobacter (Campylobacter jejuni and Campylobacter coli), with no significant differences between the medicated and nonmedicated groups. All but one of the tested Campylobacter isolates were resistant to tetracycline. Although fluoroquinolone (FQ) resistance remained low in C. jejuni (1.7%), 95.0% of the C. coli isolates were resistant to FQ. Genotyping revealed that C. jejuni sequence type 2862 (ST2862) and C. coli ST902 were the predominant genotypes in the sheep. Feed medication with tetracycline did not affect the overall prevalence, species distribution, and AMR profiles of Campylobacter, but it did increase the total Campylobacter counts in bile and gallbladder. These findings identify predominant Campylobacter clones, reveal the high prevalence of FQ-resistant C. coli, and provide new insights into the epidemiology of Campylobacter in sheep.IMPORTANCECampylobacter is a major cause of foodborne illness in humans, and antibiotic-resistant Campylobacter is considered a serious threat to public health in the United States and worldwide. As a foodborne pathogen, Campylobacter commonly exists in the intestinal tract of ruminant animals, such as sheep and cattle. Results from this study reveal the predominant genotypes and high prevalence of tetracycline (TET) and fluoroquinolone (FQ) resistance in sheep Campylobacter The finding on fluoroquinolone resistance in sheep Campylobacter is unexpected, as this class of antibiotics is not used for sheep in the United States, and it may suggest the transmission of fluoroquinolone-resistant Campylobacter from cattle to sheep. Additionally, the results demonstrate that in-feed medication with tetracycline increases Campylobacter counts in gallbladders, suggesting that the antibiotic promotes Campylobacter colonization of the gallbladder. These findings provide new information on Campylobacter epidemiology in sheep, which may be useful for curbing the spread of antibiotic-resistant Campylobacter in animal reservoirs.

Short communication: Metagenomic evaluation of skin biopsies of udder sores in dairy cows.

The objectives of this study were (a) to evaluate skin biopsies of udder sores and negative control cows for the presence of mange and nonbacterial pathogens via histopathology and (b) to identify and compare bacterial abundance in the lesions of cows with udder sores and from the skin of healthy controls from the same farms. Cows from 3 dairy farms with (n = 23) and without (n = 12) udder sore lesions were enrolled, and punch biopsies (23 lesions, 23 negative control samples of cows with lesions, and 12 control samples of cows without lesions) were collected. The biopsies were evaluated histopathologically, and their 16S metagenome was analyzed. No signs of mange or viral or fungal infections were detected histopathologically in any samples. The α diversity of microbial populations decreased in lesions, across all farms, and the abundance of spirochaetes did not notably change, compared with controls. However, compared with control samples, the microbial fractions of Fusobacterium, Helcococcus spp., Anaerococcus spp., Porphyromonas spp., Prevotella spp., and Trueperella spp. increased several-fold in lesions. In summary, our results suggest that spirochaetes, viruses, and mange are unlikely to cause udder sores. Instead, sores were associated with a marked increase in the abundance of Fusobacterium, Helcococcus, Anaerococcus, Porphyromonas, Prevotella, and Trueperella. Future studies are needed to determine which of these bacteria initiates this polymicrobial infection.

Key Role of Capsular Polysaccharide in the Induction of Systemic Infection and Abortion by Hypervirulent Campylobacter jejuni.

Campylobacter jejuni is a zoonotic pathogen, and a hypervirulent clone, named clone SA, has recently emerged as the predominant cause of ovine abortion in the United States. To induce abortion, orally ingested Campylobacter must translocate across the intestinal epithelium, spread systemically in the circulation, and reach the fetoplacental tissue. Bacterial factors involved in these steps are not well understood. C. jejuni is known to produce capsular polysaccharide (CPS), but the specific role that CPS plays in systemic infection and particularly abortion in animals remains to be determined. In this study, we evaluated the role of CPS in bacteremia using a mouse model and in abortion using a pregnant guinea pig model following oral challenge. Compared with C. jejuni NCTC 11168 and 81-176, a clone SA isolate (IA3902) resulted in significantly higher bacterial counts and a significantly longer duration of bacteremia in mice. The loss of capsule production via gene-specific mutagenesis in IA3902 led to the complete abolishment of bacteremia in mice and abortion in pregnant guinea pigs, while complementation of capsule expression almost fully restored these phenotypes. The capsule mutant strain was also impaired for survival in guinea pig sera and sheep blood. Sequence-based analyses revealed that clone SA possesses a unique CPS locus with a mosaic structure, which has been stably maintained in all clone SA isolates derived from various hosts and times. These findings establish CPS as a key virulence factor for the induction of systemic infection and abortion in pregnant animals and provide a viable candidate for the development of vaccines against hypervirulent C. jejuni.

Identification and functional analysis of two toxin-antitoxin systems in Campylobacter jejuni.

Toxin-antitoxin (TA) systems are widely distributed in bacteria and play an important role in maintaining plasmid stability. The leading foodborne pathogen, Campylobacter jejuni, can carry multiple plasmids associated with antibiotic resistance or virulence. Previously a virulence plasmid named pVir was identified in C. jejuni 81-176 and IA3902, but determining the role of pVir in pathogenesis has been hampered because the plasmid cannot be cured. In this study, we report the identification of two TA systems that are located on the pVir plasmid in 81-176 and IA3902, respectively. The virA (proteic antitoxin)/virT (proteic toxin) pair in IA3902 belongs to a Type II TA system, while the cjrA (RNA antitoxin)/cjpT (proteic toxin) pair in 81-176 belongs to a Type I TA system. Notably, cjrA (antitoxin) represents the first noncoding small RNA demonstrated to play a functional role in Campylobacter physiology to date. By inactivating the TA systems, pVir was readily cured from Campylobacter, indicating their functionality in Campylobacter. Using pVir-cured IA3902, we demonstrated that pVir is not required for abortion induction in the guinea pig model. These findings establish the key role of the TA systems in maintaining plasmid stability and provide a means to evaluate the function of pVir in Campylobacter pathobiology.

Digital dermatitis: Natural lesion progression and regression in Holstein dairy cattle over 3 years.

Bovine digital dermatitis (DD) is a leading cause of lameness in dairy cattle in the United States, with prevalence estimates as high as 30%. Whereas clinical lesions have been well described, little is known about the morphologic changes that are associated with the early stages of lesion development from normal skin to clinical lesions. This study used the Iowa DD scoring system to evaluate the epidemiology of natural lesion development by digitally photographing the rear legs of a cohort of dairy cows over a 3-yr period. Sixty-one adult Holstein dairy cows were monitored for 1,032 cow foot-months. The incidence rate of lesion development was 4 lesions per 100 cow foot-months, with the average time for a lesion to develop being 133 d. Whereas 20% of the 1,678 foot observations exhibited clinical DD lesions, an additional 55% of all observations exhibited preclinical stage 1 and 2 lesions that were indicative of DD lesion development. Utilizing the dichotomous categorization of preclinical lesions in the Iowa DD scoring system, it was found that first-lactation heifers had a higher rate of the thickened and crusted "B" type lesions, whereas the ulcerative "A" type lesions were more likely to be identified in multiparous animals. For clinical DD lesions that received topical treatment, scoring of the post-treatment lesions using the Iowa DD scoring system was found to be useful in prognosticating both the risk of recrudescence and the time until recrudescence. Systemic disease, systemic antibiotic therapy, and periparturient stress were not associated with an increase or decrease in DD lesion scores. Treatment with a single topical tetracycline wrap was associated with a significant decrease (-1.17) in DD lesion score. The results of this study demonstrate that the complex morphologic changes associated with digital dermatitis can be readily classified using the Iowa DD scoring system and the scores can be used to predict and monitor the effects of treatment and prevention measures.

Deep sequencing analysis reveals temporal microbiota changes associated with development of bovine digital dermatitis.

Bovine digital dermatitis (DD) is a leading cause of lameness in dairy cattle throughout the world. Despite 35 years of research, the definitive etiologic agent associated with the disease process is still unknown. Previous studies have demonstrated that multiple bacterial species are associated with lesions, with spirochetes being the most reliably identified organism. This study details the deep sequencing-based metagenomic evaluation of 48 staged DD biopsy specimens collected during a 3-year longitudinal study of disease progression. Over 175 million sequences were evaluated by utilizing both shotgun and 16S metagenomic techniques. Based on the shotgun sequencing results, there was no evidence of a fungal or DNA viral etiology. The bacterial microbiota of biopsy specimens progresses through a systematic series of changes that correlate with the novel morphological lesion scoring system developed as part of this project. This scoring system was validated, as the microbiota of each stage was statistically significantly different from those of other stages (P < 0.001). The microbiota of control biopsy specimens were the most diverse and became less diverse as lesions developed. Although Treponema spp. predominated in the advanced lesions, they were in relatively low abundance in the newly described early lesions that are associated with the initiation of the disease process. The consortium of Treponema spp. identified at the onset of disease changes considerably as the lesions progress through the morphological stages identified. The results of this study support the hypothesis that DD is a polybacterial disease process and provide unique insights into the temporal changes in bacterial populations throughout lesion development.

Serum concentrations of haptoglobin and haptoglobin-matrix metalloproteinase 9 (Hp-MMP 9) complexes of bovine calves in a bacterial respiratory challenge model.

BACKGROUND: Serum haptoglobin (Hp) and haptoglobin matrix metalloproteinase 9 complexes (Hp-MMP 9) have been identified as biomarkers with diagnostic potential in cattle with conditions resulting in an acute inflammatory response. The purpose of this study was to evaluate potential diagnostic applications of serum Hp and Hp-MMP 9 concentrations in calves with BRD and establish a timeline for their detection in calves experimentally challenged with Bibersteinia trehalosi and Mannheimia haemolytica. Thirty-five cross bred dairy calves were inoculated via tracheal catheterization with either a PCR confirmed leukotoxin negative B. trehalosi isolate, a PCR confirmed leukotoxin positive B. trehalosi isolate, a Mannheimia haemolytica isolate, a combination of leukotoxin negative B. trehalosi and M. haemolytica, or a negative control. Serum samples were collected throughout the study. Calves were euthanized and necropsy performed on day 10 post inoculation. RESULTS: M. haemolytica inoculated calves had increased lung involvement. Serum Hp and Hp- MMP 9 concentrations were elevated compared to the other treatment groups. Increases in serum Hp and Hp-MMP 9 concentrations for the M. haemolytica group were significantly different from other study groups on day 7 of the study. B. trehalosi inoculated calves did not have increased lung involvement compared to control calves, but the leukotoxin positive B. trehalosi group demonstrated increased serum Hp-MMP 9 concentrations from day 3 to the end of the study compared to the pre-inoculation concentrations. CONCLUSION: Serum Hp-MMP 9 concentration is a useful diagnostic tool for detecting early pulmonary inflammation in calves challenged with B. trehalosi and M. haemolytica. Serum Hp-MMP 9 may also be a useful tool in detecting subclinical pulmonary inflammation in challenged calves.

Randomized clinical trial to evaluate the pathogenicity of Bibersteinia trehalosi in respiratory disease among calves.

BACKGROUND: Bibersteinia trehalosi causes respiratory disease in ruminants particularly in wild and domestic sheep. Recently, there has been an increased number of B. trehalosi isolates obtained from diagnostic samples from bovine respiratory disease cases. This study evaluated the role of B. trehalosi in bovine respiratory disease using an intra-tracheal inoculation model in calves. Thirty six cross bred 2-3 month old dairy calves were inoculated intra-tracheally with either leukotoxin negative B. trehalosi, leukotoxin positive B. trehalosi isolate, Mannheimia haemolytica, a combination of leukotoxin negative B. trehalosi and M. haemolytica or negative control. Calves were euthanized and necropsy performed on day 10 of study. RESULTS: B. trehalosi inoculated calves did not have increased lung involvement compared to control calves. Additionally, B. trehalosi was only cultured once from the lungs of inoculated calves at necropsy. CONCLUSIONS: Based on these findings B. trehalosi may not be a primary pathogen of respiratory disease in cattle. Culture of B. trehalosi from diagnostic submissions should not be immediately identified as a primary cause of respiratory disease.

Assessing stakeholders' opinions on sharing antimicrobial susceptibility testing data from animals is key to developing a centralized database and dashboard tool.

OBJECTIVE: To present, analyze, and discuss stakeholders' opinions regarding sharing antimicrobial susceptibility testing (AST) data from animals into a centralized database and dashboard tool that would collect, aggregate, store, and analyze this type of data from veterinary diagnostic laboratories (VDLs) across the country. SAMPLE: 1 in-person focus group (9 participants), 9 virtual focus groups (49 participants), and online pre- and postmeeting surveys (76 and 35 participants, respectively). METHODS: Focus groups and surveys were conducted to assess the opinions of veterinarians, producers, researchers, diagnosticians, and government officials. RESULTS: A strong majority of stakeholders recognize AMR as a serious concern for both human and animal health and see several benefits in establishing a centralized AMR database; however, several concerns were raised associated with data confidentiality, security, curation, and harmonization. In the interest of alleviating those concerns, among other items, stakeholders suggested education and training of data users, providers, and the public in addition to assuring strong data confidentiality protections. CLINICAL RELEVANCE: Stakeholder engagement is a critical component of all stages of development, implementation, and utilization of an AMR database and dashboard tool that could be used to inform antimicrobial stewardship in veterinary medicine. This assessment of stakeholders' needs and concerns can be used to help guide future recommendations for data legal protections as well as a data confidentiality and security framework. Maintaining open communication on data usage, storage, and security as well as involvement and education of data providers, users, and the public will remain key to enabling development of an AMR database and dashboard tool for domesticated animals.

Animal drug shortages limit veterinary therapeutic options and introduce artifacts in antimicrobial sales reporting.

Supply chain issues disrupt veterinary care and cause downstream consequences that alter the practice of veterinary medicine. Antimicrobials are just 1 class of pharmaceuticals that have been impacted by supply chain issues over the last couple of years. Since February 2021, 2 sponsors/manufacturers of penicillin products have reported shortages in the active pharmaceutical ingredient. With the release of the 2021 Summary Report on Antimicrobials Sold or Distributed for Use in Food-Producing Animals by the FDA, a key finding was a 19% decrease in penicillin sales and distribution from 2020 to 2021. Herein, we provide our clinicians' professional perspective regarding how drug shortages, specifically that of penicillin, might contribute to misconstrued patterns in antimicrobial use and what can be done by veterinarians and the FDA to minimize the impact of an antimicrobial drug shortage on animal health and well-being.

Direct interaction of small non-coding RNAs CjNC140 and CjNC110 optimizes expression of key pathogenic phenotypes of Campylobacter jejuni.

Small non-coding RNAs (sRNAs) are important players in modulating gene expression in bacterial pathogens, but their functions are largely undetermined in Campylobacter jejuni, an important cause of foodborne gastroenteritis in humans. In this study, we elucidated the functions of sRNA CjNC140 and its interaction with CjNC110, a previously characterized sRNA involved in the regulation of several virulence phenotypes of C. jejuni. Inactivation of CjNC140 increased motility, autoagglutination, L-methionine concentration, autoinducer-2 production, hydrogen peroxide resistance, and early chicken colonization, indicating a primarily inhibitory role of CjNC140 for these phenotypes. Apart from motility, all these effects directly contrasted the previously demonstrated positive regulation by CjNC110, suggesting that CjNC110 and CjNC140 operate in an opposite manner to modulate physiologic processes in C. jejuni. RNAseq and northern blotting further demonstrated that expression of CjNC140 increased in the absence of CjNC110, while expression of CjNC110 decreased in the absence of CjNC140, suggesting a possibility of their direct interaction. Indeed, electrophoretic mobility shift assay demonstrated a direct binding between the two sRNAs via GA- (CjNC110) and CU- (CjNC140) rich stem-loops. Additionally, RNAseq and follow-up experiments identified that CjNC140 positively regulates p19, which encodes a key iron uptake transporter in Campylobacter. Furthermore, computational analysis revealed both CjNC140 and CjNC110 are highly conserved in C. jejuni, and the predicted secondary structures support CjNC140 as a functional homolog of the iron regulatory sRNA, RyhB. These findings establish CjNC140 and CjNC110 as a key checks-and- balances mechanism in maintaining homeostasis of gene expression and optimizing phenotypes critical for C. jejuni pathobiology. IMPORTANCE Gene regulation is critical to all aspects of pathogenesis of bacterial disease, and small non-coding RNAs (sRNAs) represent a new frontier in gene regulation of bacteria. In Campylobacter jejuni, the role of sRNAs remains largely unexplored. Here, we investigate the role of two highly conserved sRNAs, CjNC110 and CjNC140, and demonstrate that CjNC140 displays a primarily inhibitory role in contrast to a primarily activating role for CjNC110 for several key virulence-associated phenotypes. Our results also revealed that the sRNA regulatory pathway is intertwined with the iron uptake system, another virulence mechanism critical for in vivo colonization. These findings open a new direction for understanding C. jejuni pathobiology and identify potential targets for intervention for this major foodborne pathogen.

Molecular evidence for zoonotic transmission of an emergent, highly pathogenic Campylobacter jejuni clone in the United States.

Campylobacter jejuni is a major zoonotic pathogen. A highly virulent, tetracycline-resistant C. jejuni clone (clone SA) has recently emerged in ruminant reservoirs and has become the predominant cause of sheep abortion in the United States. To determine whether clone SA is associated with human disease, we compared the clinical isolates of clone SA from sheep abortions with the human isolates of the PulseNet National Campylobacter databases at the CDC and the FDA using pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and serotyping. The combined SmaI and KpnI PFGE pattern designations of clone SA from sheep were indistinguishable from those of 123 (9.03%) human C. jejuni isolates (total, 1,361) in the CDC database, among which 56 were associated with sporadic infections and 67 were associated with outbreaks that occurred in multiple states from 2003 to 2010. Most of the outbreaks were attributed to raw milk, while the sources for most of the sporadic cases were unknown. All clone SA isolates examined, including PFGE-matched human isolates, belong to sequence type 8 (ST-8) by MLST and serotype HS:1,8, further indicating the clonality of the related isolates from different host species. Additionally, C. jejuni clone SA was identified in raw milk, cattle feces, the feces and bile of healthy sheep, and abortion cases of cattle and goats, indicating the broad distribution of this pathogenic clone in ruminants. These results provide strong molecular and epidemiological evidence for zoonotic transmission of this emergent clone from ruminants to humans and indicate that C. jejuni clone SA is an important threat to public health.

Bioavailability and pharmacokinetics of oral meloxicam in llamas.

BACKGROUND: South American camelids in the United States have rapidly developed into an important agricultural industry in need of veterinary services. Pain management is challenging in camelids because there are no drugs currently approved by the U.S. Food and Drug Administration for use in these species. Dosage regimens used for many therapeutic drugs have been extrapolated from other ruminants; however, the pharmacokinetics, in camelids, may differ from those of other species. Studies investigating the pharmacokinetics of cyclooxygenase-2 (COX-2) selective non-steroidal anti-inflammatory drugs in camelids are deficient in the published literature. Six adult llamas (121- 168 kg) were administered either a 1 mg/kg dose of oral or a 0.5 mg/kg dose of IV meloxicam in a randomized cross-over design with an 11 day washout period between treatments. Plasma samples collected up to 96 hours post-administration were analyzed by high pressure liquid chromatography and mass spectrometry detection (HPLC-MS) followed by non-compartmental pharmacokinetic analysis. RESULTS: A mean peak plasma concentration (CMAX) of 1.314 µg/mL (Range: 0.826 - 1.776 µg/mL) was recorded at 21.4 hours (Range: 12.0 - 24.0 hours) with a half-life (T ½ λz) of 22.7 hours (Range: 18.0 - 30.8 hours) after oral meloxicam administration. In comparison, a half-life (T ½ λz) of 17.4 hours (Range: 16.2 - 20.7 hours) was demonstrated with IV meloxicam administration. The oral bioavailability (F) of meloxicam (dose normalized) was 76% (Range: 48 - 92%). No adverse effects associated with either treatment modality were observed in the llamas. CONCLUSIONS: The mean bioavailability (F) of oral meloxicam was 76% indicating a high degree of gastrointestinal absorption. Plasma meloxicam concentrations >0.2 µg/mL were maintained for up to 72 h after oral administration; >0.2 µg/mL is considered to be the concentration of meloxicam required for analgesic effects in other species such as the horse. These data suggest that a single dosage of oral meloxicam at 1 mg/kg could potentially maintain therapeutic concentrations in plasma for up to 3 days in adult llamas.

Impacts of Gut Microbiota on the Immune System and Fecal Microbiota Transplantation as a Re-Emerging Therapy for Autoimmune Diseases.

The enormous and diverse population of microorganisms residing in the digestive tracts of humans and animals influence the development, regulation, and function of the immune system. Recently, the understanding of the association between autoimmune diseases and gut microbiota has been improved due to the innovation of high-throughput sequencing technologies with high resolutions. Several studies have reported perturbation of gut microbiota as one of the factors playing a role in the pathogenesis of many diseases, such as inflammatory bowel disease, recurrent diarrhea due to Clostridioides difficile infections. Restoration of healthy gut microbiota by transferring fecal material from a healthy donor to a sick recipient, called fecal microbiota transplantation (FMT), has resolved or improved symptoms of autoimmune diseases. This (re)emerging therapy was approved for the treatment of drug-resistant recurrent C. difficile infections in 2013 by the U.S. Food and Drug Administration. Numerous human and animal studies have demonstrated FMT has the potential as the next generation therapy to control autoimmune and other health problems. Alas, this new therapeutic method has limitations, including the risk of transferring antibiotic-resistant pathogens or transmission of genes from donors to recipients and/or exacerbating the conditions in some patients. Therefore, continued research is needed to elucidate the mechanisms by which gut microbiota is involved in the pathogenesis of autoimmune diseases and to improve the efficacy and optimize the preparation of FMT for different disease conditions, and to tailor FMT to meet the needs in both humans and animals. The prospect of FMT therapy includes shifting from the current practice of using the whole fecal materials to the more aesthetic transfer of selective microbial consortia assembled in vitro or using their metabolic products.

Science communication challenges about antimicrobial resistance in animal agriculture: insights from stakeholders.

Background: Communicating about antimicrobial resistance (AMR) and antimicrobial stewardship (AMS) requires technical knowledge, consideration of audience values and appropriate identification of communication strategies for multiple audiences. Within the context of animal agriculture, communicating about AMR represents an important and complex endeavour for veterinarians, governmental agencies, producers and the industry to convey policy and practice information regarding the use of antimicrobials in food animals. Objectives: To assess the science communication challenges related to AMR by identifying the motivations, goals and struggles of animal agriculture stakeholders when communicating about AMR and AMS. Methods: Participants attending a meeting on AMR communication in animal agriculture (N = 80) completed a workshop on science communication, including small group meetings with oral/written comments collected. Participants included veterinarians, government agency representatives, industry stakeholders and producers. Results: Results indicated participants believed providing more accurate information would resolve misunderstanding and concern about AMR to other stakeholders, counter to recommendations of science communicators. Other participants noted beliefs about the utility of stories in trying to explain how AMS is normative and consistent with the values of all parties interested in animal agriculture. Participants noted the importance of public engagement, even if the participants' perceived target audiences did not include the public. Conclusions: Communicating about AMR and AMS in animal agriculture contexts provide unique challenges. Few evidence-based recommendations are available for science communicators in these contexts and more research is needed to improve the quality of communication about AMR and AMS in animal agriculture.