Newcastle disease vaccines-A solved problem or a continuous challenge?

Proposals to update the harmonised monitoring and reporting of antimicrobial resistance (AMR) from a public health perspective in Salmonella, Campylobacter coli, Campylobacter jejuni, Escherichia coli, Enterococcus faecalis, Enterococcus faecium and methicillin-resistant Staphylococcus aureus (MRSA) from food-producing animals and derived meat in the EU are presented in this report, accounting for recent trends in AMR, data collection needs and new scientific developments. Phenotypic monitoring of AMR in bacterial isolates, using microdilution methods for testing susceptibility and interpreting resistance using epidemiological cut-off values is reinforced, including further characterisation of those isolates of E. coli and Salmonella showing resistance to extended-spectrum cephalosporins and carbapenems, as well as the specific monitoring of ESBL/AmpC/carbapenemase-producing E. coli. Combinations of bacterial species, food-producing animals and meat, as well as antimicrobial panels have been reviewed and adapted, where deemed necessary. Considering differing sample sizes, numerical simulations have been performed to evaluate the related statistical power available for assessing occurrence and temporal trends in resistance, with a predetermined accuracy, to support the choice of harmonised sample size. Randomised sampling procedures, based on a generic proportionate stratified sampling process, have been reviewed and reinforced. Proposals to improve the harmonisation of monitoring of prevalence, genetic diversity and AMR in MRSA are presented. It is suggested to complement routine monitoring with specific cross-sectional surveys on MRSA in pigs and on AMR in bacteria from seafood and the environment. Whole genome sequencing (WGS) of isolates obtained from the specific monitoring of ESBL/AmpC/carbapenemase-producing E. coli is strongly advocated to be implemented, on a voluntary basis, over the validity period of the next legislation, with possible mandatory implementation by the end of the period; the gene sequences encoding for ESBL/AmpC/carbapenemases being reported to EFSA. Harmonised protocols for WGS analysis/interpretation and external quality assurance programmes are planned to be provided by the EU-Reference Laboratory on AMR.

Technical specifications on harmonised monitoring of antimicrobial resistance in zoonotic and indicator bacteria from food-producing animals and food

Members of the genus Campylobacter remain a leading cause of bacterial gastroenteritis worldwide Infection is usually self-limiting but in severe cases may require antibiotic treatment In a recent statement by the World Health Organization (WHO) Campylobacter was named as one of the 12 bacteria that pose the greatest threat to human health because they are resistant to antibiotics In this mini review we describe recent trends in fluoroquinolone (FQ) (particularly ciprofloxacin) resistance in strains of members of the genus Campylobacter isolated from livestock and clinical samples from several countries Using evidence from phenotyping surveys and putative resistance prediction from DNA sequence data, we discuss the acquisition and spread of FQ resistance and the role of horizontal gene transfer and describe trends in FQ-resistance in samples from livestock and clinical cases This review emphasises that FQ resistance remains common among isolates of members of the genus Campylobacter from various sources

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Trends in fluoroquinolone resistance in Campylobacter.

Campylobacter jejuni, a common foodborne zoonotic pathogen, causes gastroenteritis worldwide and is increasingly resistant to antibiotics. We aimed to investigate the antimicrobial resistance (AMR) genotypes of C. jejuni isolated from humans, poultry and birds from wild and urban Italian habitats to identify correlations between phenotypic and genotypic AMR in the isolates. Altogether, 644 C. jejuni isolates from humans (51), poultry (526) and wild- and urban-habitat birds (67) were analysed. The resistance phenotypes of the isolates were determined using the microdilution method with EUCAST breakpoints, and AMR-associated genes and single nucleotide polymorphisms were obtained from a publicly available database. Antimicrobial susceptibility testing showed that C. jejuni isolates from poultry and humans were highly resistant to ciprofloxacin (85.55% and 76.47%, respectively), nalidixic acid (75.48% and 74.51%, respectively) and tetracycline (67.87% and 49.02%, respectively). Fewer isolates from the wild- and urban-habitat birds were resistant to tetracycline (19.40%), fluoroquinolones (13.43%), and quinolone and streptomycin (10.45%). We retrieved seven AMR genes (tet (O), cmeA, cmeB, cmeC, cmeR, blaOXA-61 and blaOXA-184) and gyrA-associated point mutations. Two major B-lactam genes called blaOXA-61 and blaOXA-184 were prevalent at 62.93% and 82.08% in the poultry and the other bird groups, respectively. Strong correlations between genotypic and phenotypic resistance were found for fluoroquinolones and tetracycline. Compared with the farmed chickens, the incidence of AMR in the C. jejuni isolates from the other bird groups was low, confirming that the food-production birds are much more exposed to antimicrobials. The improper and overuse of antibiotics in the human population and in animal husbandry has resulted in an increase in antibiotic-resistant infections, particularly fluoroquinolone resistant ones. Better understanding of the AMR mechanisms in C. jejuni is necessary to develop new strategies for improving AMR programs and provide the most appropriate therapies to human and veterinary populations.

/pdf/antimicrobial-resistance-genotypes-and-phenotypes-of-2i4jzhx0m0.pdf

Antimicrobial resistance genotypes and phenotypes of Campylobacter jejuni isolated in Italy from humans, birds from wild and urban habitats, and poultry.

Currently Campylobacter is the most commonly reported zoonosis in developed and developing countries. In the European Union, the number of reported confirmed cases of human campylobacteriosis was 246,307 in 2016, which represents 66.3 cases per 100,000 population. The genus Campylobacter includes 31 species with 10 subspecies. Within the genus Campylobacter, C. jejuni subsp. jejuni and C. coli are most frequently associated with human illness. Mainly, the infection is sporadic and self-limiting, although some cases of outbreaks have been also reported and some complications such as Guillain-Barre syndrome might appear sporadically. Although campylobacters are fastidious microaerophilic, unable to multiply outside the host and generally very sensitive, they can adapt and survive in the environment, exhibiting aerotolerance and resistance to starvation. Many mechanisms are involved in this, including pathogenicity, biofilm formation, and antibiotic resistant pathways. This chapter reviews the sources, transmission routes, the mechanisms, and strategies used by Campylobacter to persist in the whole food chain, from farm to fork. Additionally, different strategies are recommended for application along the poultry food chain to avoid the public health risk associated with this pathogen.

Campylobacter in the Food Chain.

Thermostable Newcastle disease virus (NDV) vaccines have been used widely to control Newcastle disease for village poultry flocks, due to their independence of cold chains for delivery and storage. To explore the potential use of thermostable NDV as a vaccine vector, an infectious clone of thermostable avirulent NDV strain TS09-C was developed using reverse genetics technology. The GFP gene, along with the self-cleaving 2A gene of foot-and-mouth disease virus and ubiquitin monomer (2AUbi), were inserted immediately upstream of the NP (nucleocapsid protein), M (matrix protein) or L (large polymerase protein) gene translation start codon in the TS09-C infectious clone. Detection of GFP expression in the recombinant virus-infected cells showed that the recombinant virus, rTS-GFP/M, with the GFP gene inserted into the M gene expressed the highest level of GFP. The rTS-GFP/M virus retained the same thermostability, growth dynamics and pathogenicity as its parental rTS09-C virus. Vaccination of specific-pathogen-free chickens with the rTS-GFP/M virus conferred complete protection against virulent NDV challenge. Taken together, the data suggested that the rTS09-C virus could be used as a vaccine vector to develop bivalent thermostable vaccines against Newcastle disease and the target avian diseases for village chickens, especially in the developing and least-developed countries.

Development of a novel thermostable Newcastle disease virus vaccine vector for expression of a heterologous gene

Sequence analysis of 79 ciprofloxacin-resistant Campylobacter jejuni isolates collected in China showed resistance-related sequence variations in gyrA and CmeR-Box. All the isolates contain an identical Thr-86-Ile substitution in GyrA. Several novel CmeR-Box variations, including point substitutions, deletion, and insertion, were identified. The point insertion or deletion led to dramatically reduced binding of CmeR to the cmeABC promoter, which significantly increases the expression of cmeABC and contributes to the high fluoroquinolone resistance.

Correlation between gyrA and CmeR Box Polymorphism and Fluoroquinolone Resistance in Campylobacter jejuni Isolates in China.

The invention relates to a fluorescent quantitative PCR rapid detection kit for specifically detecting clostridium perfringens enterotoxin positive bacteria infection. The detection kit comprises (a) a fluorescent quantitative reaction solution; (b) clostridium perfringens exotoxin cpa positive and clostridium perfringens enterotoxin cpe positive quality control substances; and (c) a negative quality control substance, wherein the fluorescent quantitative reaction solution comprises 2 pairs of primers and one pair of probes, namely a forward primer cpa01 and a reverse primer cpa02 of clostridium perfringens exotoxin cpa and a fluorescence probe cpap, as well as a forward primer cpe01 and a reverse primer cpe02 of clostridium perfringens enterotoxin cpe and a fluorescence probe cpep. The detection kit disclosed by the invention has the advantages that positive clostridium perfringens of the enterotoxin cpe can be rapidly diagnosed; the specificity is high, the sensitivity is high, and the false positive rate is low; and moreover, the detection speed is high, and only one and a half hours are needed.

Clostridium perfringens enterotoxin positive bacteria dual fluorescent quantitative PCR rapid detection kit

The invention discloses a Newcastle disease virus heat-resistant transformation method and application of the Newcastle disease virus heat-resistant transformation method. The heat-resistant characteristic of the Newcastle disease virus is specifically and remarkably improved through an HN gene replacement method. The non-heat-resistant Newcastle disease virus is transformed at the transcription plasmid level through the RNA virus reverse genetic technology, the HN gene of the non-heat-resistant Newcastle disease virus is replaced with the HN gene of the heat-resistant Newcastle disease virus, host cells are transfected by the transformed transcription plasmid, rescue is conducted to obtain the heat-resistant transformed Newcastle disease virus, and therefore the heat-resistant characteristic of the Newcastle disease virus is greatly improved. The heat-resistant characteristic of the Newcastle disease virus is remarkably improved through the artificial recombination mode for the first time, and a non-heat-resistant Newcastle disease vaccine strain LaSota is successfully transformed into a heat-resistant Newcastle disease vaccine strain rT-HN. The method can be widely applied to heat-resistant transformation of Newcastle disease vaccine strains, and has great application prospects on the aspects of heat-resistant, safe and efficient Newcastle disease vaccine research and the like.

Newcastle disease virus heat-resistant transformation method and application

Riemerella anatipestifer is an important bacterial pathogen associated with epizootic infections in waterfowl and various other birds. Riemerella anatipestifer strain RA-JLLY is an avirulent strain, isolated from the brain of an old duck in Hubei province, China. Here, we report the genome sequence of this species.

Genome Sequence of Avirulent Riemerella anatipestifer Strain RA-JLLY.

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