Bovine viral diarrhea virus (BVDV) is a pestivirus which infects both domestic animals and wildlife species worldwide. In China, cattle are often infected with BVDV of different genotypes, but there is very limited knowledge regarding BVDV infection in Chinese yaks and the genetic diversity of the virus. The objectives of this study were to detect viral infection in yaks in Qinghai, China and to determine the genotypes of BVDV based on analysis of the 5′untranslated region (5′UTR) and N-terminal protease (Npro) region.

Phage therapy is a promising therapeutic option for treating bacterial infections that do not respond to common antimicrobial treatments. Biofilm-mediated infections are particularly difficult to treat with traditional antibiotics, and the emergence of antibiotic-resistant strains has further complicated the situation. Pseudomonas aeruginosa is a bacterial pathogen that causes chronic infections and is highly resistant to many antibiotics.

Infectious diseases are a serious threat to the existence of animals and humans' life. In the 21st century, the emergence and re‐emergence of several zoonotic and non‐zoonotic global pandemic diseases of socio‐economic importance has affected billions of humans and animals. The need for expensive equipment and laboratories, non‐availability of on‐site testing abilities, with time‐consuming and low sensitivity and specificity issues of currently available diagnostic techniques to identify these pathogenic micro‐organisms on a large scale highlighted the need for developing cheap, portable environment friendly diagnostic methods. In recent years, these issues have been addressed by clustered regularly interspaced palindromic repeats (CRISPR)‐based diagnostic platforms that have transformed the molecular diagnostic field due to their outstanding ultra‐sensitive nucleic acid detecting capabilities. In this study, we highlight the types, potential of different Cas proteins, and amplification systems. We also illuminate the application of currently available CRISPR integrated setups on the diagnosis of infectious diseases, majorly in food‐producing animals (pigs, ruminants, poultry, and aquaculture), domestic pets (dogs and cats), and diseases of zoonotic importance. We conclude the challenges and future perspectives of using these systems to rapidly diagnose and treat other infectious diseases and also develop control strategies to prevent the spread of pathogenic organisms.

Riemerella anatipestifer (R. anatipestifer) is a multidrug-resistant bacterium and an important pathogen responsible for major economic losses in the duck industry. Our previous study revealed that the efflux pump is an important resistance mechanism of R. anatipestifer. Bioinformatics analysis indicated that the GE296_RS02355 gene (denoted here as RanQ), a putative small multidrug resistance (SMR)-type efflux pump, is highly conserved in R. anatipestifer strains and important for the multidrug resistance. In the present study, we characterized the GE296_RS02355 gene in R. anatipestifer strain LZ-01. First, the deletion strain RA-LZ01ΔGE296_RS02355 and complemented strain RA-LZ01cΔGE296_RS02355 were constructed. When compared with that of the wild-type (WT) strain RA-LZ01, the mutant strain ΔRanQ showed no significant influence on bacterial growth, virulence, invasion and adhesion, morphology biofilm formation ability, and glucose metabolism. In addition, the ΔRanQ mutant strain did not alter the drug resistance phenotype of the WT strain RA-LZ01 and displayed enhanced sensitivity toward structurally related quaternary ammonium compounds, such as benzalkonium chloride and methyl viologen, which show high efflux specificity and selectivity. This study may help elucidate the unprecedented biological functions of the SMR-type efflux pump in R. anatipestifer. Thus, if this determinant is horizontally transferred, it could cause the spread of quaternary ammonium compound resistance among bacterial species.

Colistin (polymyxin E) is a group of cationic antimicrobial cyclic peptides and is recognized as a last‐resort defense against lethal infections with carbapenem‐resistant pathogens. In addition to the plasmid‐borne mobilized phosphoethanolamine (PEA) transferases, the functional expression of lipid A‐modifying enzymes encoded on chromosomes has been attributed to intrinsic bacterial colistin resistance. However, the mechanisms of colistin resistance in Riemerella anatipestifer remain unknown. Herein, the GE296_RS09715 gene‐encoded Lipid A PEA transferases (RaEptA) was identified in R. anatipestifer . Genetic and structural analyses revealed that the amino acid sequence of RaEptA shared 26.6%–33.1% similarities with the family of Lipid A PEA transferases (EptA) and MCR‐like proteins and have defined 12 residues that contribute to the formation of phosphatidylethanolamine (PE)‐recognizable cavities. Comparative analyses of colistin resistance in RA‐LZ01 and RA‐LZ01ΔRaEptA showed the level of colistin has fallen from 96 μg mL ⁻¹ down to 24 ~ 32 μg mL ⁻¹ . Site‐directed mutagenesis assay of the PE‐binding cavity and expression of the mutants reveals that K309‐rRaEptA can remodel the surface of Escherichia coli and rendering it resistant to colistin, suggesting this point‐mutation of P309K is necessary for EptA‐mediated lipid A modification. Moreover, the virulence of RA‐LZ01ΔRaEptA was attenuated compared with RA‐LZ01 both in vivo and vitro. Taken together, the results represent the RaEptA involved in the colistin resistance and pathogenicity, and the P309K mutation might alter bacterial adaptation and increase the spread of colistin resistance from R. anatipestifer to other gram‐negative bacteria. The findings of this study suggest another scenario for the spread of colistin resistance genes and should be considered by a wide audience.