EISSN : 2731-0442
Published by: Springer Science and Business Media LLC (10.1186)
Total articles ≅ 7
Articles in this journal
Animal Diseases, Volume 1, pp 1-11; doi:10.1186/s44149-021-00009-5
The emergence and dissemination of colistin resistance in Enterobacteriaceae mediated by plasmid-borne mcr genes in recent years now pose a threat to public health. In this study, we isolated and characterized colistin-resistant and/or mcr-positive E. coli from pig farms in Central China. Between 2018 and 2019, 594 samples were collected and recovered 445 E. coli isolates. Among them, 33 with colistin resistance phenotypes and 37 that were positive for mcr genes were identified, including 34 positive for mcr-1, one positive for mcr-3, and two positive for both mcr-1 and mcr-3. An insertion of nine bases (“CTGGATACG”) into mcr-1 in four mcr-positive isolates led to gene dysfunction, and therefore did not confer the colistin resistance phenotype. Antimicrobial susceptibility testing revealed that 37 mcr-positive isolates showed severe drug resistance profiles, as 50% of them were resistant to 20 types of antibiotics. Multilocus sequence typing revealed a heterogeneous group of sequence types in mcr-positive isolates, among which ST10 (5/37), ST156 (5/37), and ST617 (4/37) were the predominant types. Plasmid conjugation assays showed that mcr-carrying plasmids of 25 mcr-positive isolates were conjugated with E. coli recipient, with conjugation frequencies ranging from 1.7 × 10-6 to 4.1 × 10-3 per recipient. Conjugation of these mcr genes conferred a colistin resistance phenotype upon the recipient bacterium. PCR typing of plasmids harbored in the 25 transconjugants determined six types of plasmid replicons, including IncX4 (14/25), FrepB (4/25), IncI2 (3/25), IncHI2 (2/25), FIB (1/25), and IncI1 (1/25). This study contributes to the current understanding of antibiotic resistance and molecular characteristics of colistin-resistant E. coli in pig farms.
Animal Diseases, Volume 1, pp 1-9; doi:10.1186/s44149-021-00008-6
Porcine circovirus type 3 (PCV3), which was first detected in the United States of America in 2015, is a potential threat to the swine industry. However, the prevalence of PCV3 in Shanxi Province, China, is unclear. In this research, the prevalence and genetic diversity of PCV3 were investigated in above area. Lung tissue samples (n = 491) from 19 pig slaughterhouses across 11 cities throughout Shanxi Province were analyzed for PCV3 infection by PCR in 2019. The results showed that PCV3 positive rates in slaughterhouses and individuals were 100% (19/19) and 86.76% (426/491), respectively. PCV2 and PCV3 double-positive rates in slaughterhouses and individuals were 100% (19/19) and 59.27% (291/491), respectively. PCR positive samples were further sequenced and 8 PCV3 isolates were identified. The nucleotide homology of these isolates with other PCV3 isolates in NCBI database was 97.45–99.90%. A phylogenetic analysis, based on the complete genomic sequence and ORF2, divided these PCV3 strains into 2 major groups. Based on A24/V and R27/K amino acid mutations of capsid protein, the 8 identified PCV3 strains were separated to 2 clades. This was the first detailed investigation into the epidemiology of PCV3 in Shanxi Province. Our findings enabled us to assess the possibility of widespread transmission from this region. Thus, current findings establish a basis for further studies of genetic variations in PCV3 strains circulating in China.
Animal Diseases, Volume 1, pp 1-15; doi:10.1186/s44149-021-00007-7
Staphylococcal superantigen (SAg) toxins are the most notable virulence factors associated with Staphylococcus aureus, which is a pathogen associated with serious community and hospital acquired infections in humans and various diseases in animals. Recently, SAg toxins have become a superfamily with 29 types, including staphylococcal enterotoxins (SEs) with emetic activity, SE-like toxins (SEls) that do not induce emesis in primate models or have yet not been tested, and toxic shock syndrome toxin-1 (TSST-1). SEs and SEls can be subdivided into classical types (SEA to SEE) and novel types (SEG to SElY, SE01, SE02, SEl26 and SEl27). The genes of SAg toxins are located in diverse accessory genetic elements and share certain structural and biological properties. SAg toxins are heat-stable proteins that exhibit pyrogenicity, superantigenicity and capacity to induce lethal hypersensitivity to endotoxin in humans and animals. They have multiple pathogenicities that can interfere with normal immune function of host, increase the chances of survival and transmission of pathogenic bacteria in host, consequently contribute to the occurrence and development of various infections, persistent infections or food poisoning. This review focuses on the following aspects of SAg toxins: (1) superfamily members of classic and novelty discovered staphylococcal SAgs; (2) diversity of gene locations and molecular structural characteristics; (3) biological characteristics and activities; (4) multi-pathogenicity of SAgs in animal and human diseases, including bovine mastitis, swine sepsis, abscesses and skin edema in pig, arthritis and septicemia in poultry, and nosocomial infections and food-borne diseases in humans.
Animal Diseases, Volume 1, pp 1-11; doi:10.1186/s44149-021-00001-z
Cage layer osteoporosis (CLO) is a common bone metabolism disease in the breeding industry of China. However, effective prevention for CLO has not been developed. Icariin (ICA), the main bioactive component of the Chinese herb Epimedium, has been shown to have good therapeutic effects on bone-related diseases. In this study, the effects of ICA were further evaluated in a low-calcium diet-induced CLO, and a serum metabolomics assay was performed to understand the underlying mechanisms. A total of 144 31-wk-old Lohmann pink-shell laying hens were randomly allocated to 4 groups with 6 replicates of 6 hens per replicate. The 4 dietary treatment groups consisted of a basal diet (3.5% calcium), a low-calcium diet (2.0% calcium), and a low-calcium diet supplemented with 0.5 or 2.0 g/kg ICA. The results showed that ICA exerted good osteoprotective effects on low-calcium diet-induced CLO. ICA significantly increased femur bone mineral density, improved bone microstructure, decreased bone metabolic level, and upregulated mRNA expression of bone formation genes in femoral bone tissue. Serum untargeted metabolomics analysis showed that 8 metabolite levels were significantly changed after ICA treatment, including increased contents of 7-dehydrocholesterol, 7-oxocholesterol, desmosterol, PC (18:1(9Z)/18:1(9Z)), PS (18:0/18:1(9Z)), N,N-dimethylaniline and 2-hydroxy-butanoic acid and decreased N2,N2-dimethylguanosine. Metabolic pathway analysis based on the above 8 metabolites indicated that ICA mainly perturbed steroid biosynthesis and glycerophospholipid metabolism. These findings suggest that ICA can effectively prevent bone loss in low-calcium diet-induced CLO by mediating steroid biosynthesis and glycerophospholipid metabolism and provide new information for the regulation of bone metabolic diseases.
Animal Diseases, Volume 1, pp 1-9; doi:10.1186/s44149-021-00003-x
Bile acids (BAs) are evolutionally conserved molecules synthesized in the liver from cholesterol to facilitating the absorption of fat-soluble nutrients. In the intestines, where enteric viruses replicate, BAs also act as signaling molecules that modulate various biological functions via activation of specific receptors and cell signaling pathways. To date, BAs present either pro-viral or anti-viral effects for the replication of enteric viruses in vivo and in vitro. In this review, we summarized current information on biosynthesis, transportation and metabolism of BAs and the role of BAs in replication of enteric caliciviruses, rotaviruses, and coronaviruses. We also discussed the application of BAs for cell culture adaptation of fastidious enteric caliciviruses and control of virus infection, which may provide novel insights into the development of antivirals and/or disinfectants for enteric viruses.
Animal Diseases, Volume 1, pp 1-2; doi:10.1186/s44149-021-00006-8
Animal Diseases, Volume 1, pp 1-10; doi:10.1186/s44149-021-00002-y
The zoonotic cryptosporidiosis is globally distributed, one of the major diarrheal diseases in humans and animals. Cryptosporidium oocysts are also one of the major environmental concerns, making it a pathogen that fits well into the One Health concept. Despite its importance, fully effective drugs are not yet available. Anti-cryptosporidial drug discovery has historically faced many unusual challenges attributed to unique parasite biology and technical burdens. While significant progresses have been made recently, anti-cryptosporidial drug discovery still faces a major obstacle: identification of systemic drugs that can be absorbed by patients experiencing watery diarrhea and effectively pass through electron-dense (ED) band at the parasite-host cell interface to act on the epicellular parasite. There may be a need to develop an in vitro assay to effectively screen hits/leads for their capability to cross ED band. In the meantime, non-systemic drugs with strong mucoadhesive properties for extended gastrointestinal exposure may represent another direction in developing anti-cryptosporidial therapeutics. For developing both systemic and non-systemic drugs, a non-ruminant animal model exhibiting diarrheal symptoms suitable for routine evaluation of drug absorption and anti-cryptosporidial efficacy may be very helpful.
Animal Diseases, Volume 1, pp 1-8; doi:10.1186/s44149-021-00004-w
Three major human coronavirus disease outbreaks, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and 2019 coronavirus disease (COVID-19), occurred in the twenty-first century and were caused by different coronaviruses (CoVs). All these viruses are considered to have originated from bats and transmitted to humans through intermediate hosts. SARS-CoV-1 and SARS-CoV-2, disease agent of COVID-19, shared around 80% genomic similarity, and thus belong to SARS-related CoVs. As a natural reservoir of viruses, bats harbor numerous other SARS-related CoVs that could potentially infect humans around the world, causing SARS or COVID-19 like outbreaks in the future. In this review, we summarized the current knowledge of CoVs on geographical distribution, genetic diversity, cross-species transmission potential and possible pathogenesis in humans, aiming for a better understanding of bat SARS-related CoVs in the context of prevention and control.
Animal Diseases, Volume 1, pp 1-28; doi:10.1186/s44149-021-00005-9
The frequent emergence of coronavirus (CoV) epidemics has seriously threatened public health and stock farming. The major hosts for CoVs are birds and mammals. Although most CoVs inhabit their specific natural hosts, some may occasionally cross the host barrier to infect livestock and even people, causing a variety of diseases. Since the beginning of the new century, increasing attention has been given to research on CoVs due to the emergence of highly pathogenic and genetically diverse CoVs that have caused several epidemics, including the recent COVID-19 pandemic. CoVs belong to the Coronaviridae family of the Nidovirales order. Recently, advanced techniques for viral detection and viral genome analyses have enabled characterization of many new nidoviruses than ever and have greatly expanded the Nidovirales order with new classification and nomenclature. Here, we first provide an overview of the latest research progress in the classification of the Nidovirales order and then introduce the host range, genetic variation, genomic pattern and pathogenic features of epidemic CoVs and other epidemic viruses. This information will promote understanding of the phylogenetic relationship and infectious transmission of various pathogenic nidoviruses, including epidemic CoVs, which will benefit virological research and viral disease control.