Characterization of Ornithobacterium rhinotracheale from commercial layer chickens in eastern Japan

Application of extremophile cell factories in industrial biotechnology

Due to the extreme living conditions, extremophiles have unique characteristics in morphology, structure, physiology, biochemistry, molecular evolution mechanism and so on. Extremophiles have superior growth and synthesis capabilities under harsh conditions compared to conventional microorganisms, allowing for unsterilized fermentation processes and thus better performance in low-cost production. In recent years, due to the development and optimization of molecular biology, synthetic biology and fermentation technology, the identification and screening technology of extremophiles has been greatly improved. In this review, we summarize techniques for the identification and screening of extremophiles and review their applications in industrial biotechnology in recent years. In addition, the facts and perspectives gathered in this review suggest that next-generation industrial biotechnology (NGIBs) based on engineered extremophiles holds the promise of simplifying biofuturing processes, establishing open, non-sterilized continuous fermentation production systems, and utilizing low-cost substrates to make NGIBs attractive and cost-effective bioprocessing technologies for sustainable manufacturing.

Complete Genome Sequences of Three Ornithobacterium rhinotracheale Strains from Avian Sources, Using Hybrid Nanopore-Illumina Assembly

Ornithobacterium rhinotracheale has been associated with respiratory disease in poultry, particularly turkeys, leading to significant economic losses. However, O. rhinotracheale is poorly studied, and a very limited number of complete genomes are available. Here, we report the complete genome sequences of three O. rhinotracheale strains, generated using a Nanopore-Illumina hybrid assembly approach.

The Microbial Community of the Respiratory Tract of Commercial Chickens and Turkeys

Respiratory tract health critically affects the performance of commercial poultry. This report presents data on the microbial community in these organs from a comprehensive study of laying chickens and turkey breeders. The main objective was to characterize and compare the compositions of the respiratory system bacteria isolated from birds of different ages and geographical locations in Poland. Using samples from 28 turkey and 26 chicken flocks, the microbial community was determined by 16S ribosomal RNA sequencing. There was great variability between flocks. The diversity and abundance of upper respiratory tract (URT) bacteria was greater in chickens than in turkeys. At the phyla level, the URT of the chickens was heavily colonized by Proteobacteria, which represented 66.4% of the total microbiota, while in turkeys, this phylum constituted 42.6% of all bacteria. Firmicutes bacteria were more abundant in turkeys (43.2%) than in chickens (24.1%). The comparison of the respiratory tracts at the family and genus levels showed the diversity and abundance of amplicon sequence variants (ASV) differing markedly between the species. Potentially pathogenic bacteria ASV were identified in the respiratory tract, which are not always associated with clinical signs, but may affect bird productivity and performance. The data obtained, including characterization of the bacterial composition found in the respiratory system, may be useful for developing effective interventions strategies to improve production performance and prevent and control disease in commercial laying chickens and turkeys.

Occurrence of Ornithobacterium rhinotracheale in Polish turkey flocks

Introduction

Ornithobacterium rhinotracheale (ORT) causes significant economic losses to the poultry industry around the world. The bacterium often affects poultry as part of multiple infections causing very serious clinical signs that are usually not limited only to the respiratory system. This study’s main objective was the retrospective detection and identification of ORT in turkey flocks.

Material and Methods

ORT identification was performed in 6,225 samples taken from 133 different flocks between 2015 and 2020. Molecular methods were used, specifically real-time PCR and traditional PCR. We focused on partial 16S rRNA gene sequences of isolates, which were compared with sequences obtained from GenBank. The reaction products were analysed phylogenetically. Molecular methods indicating secondary infections was carried out, and the bacterial composition of the upper respiratory tract was 16S metasequenced for selected flocks to identify any other pathogens.

Results

The presence of ORT was detected in 30.83% of samples by real-time PCR and 28.57% by PCR. Phylogenetic analysis of the PCR products from the turkeys samples showed that their sequences resolved into two main genetic groups. Tests for the occurrence of secondary infections showed the presence of Mycoplasma gallisepticum and M. synoviae in some samples but the total absence of Bordetella avium. The upper respiratory tract in turkeys was dominated by two major phyla Firmicutes and Proteobacteria. At the genus level, the genera Ornithobacterium, Mycoplasma, Gallibacterium, Avibacterium, and Escherichia-Shigella were found which may include pathogenic bacteria that can cause clinical symptoms.

Conclusion

The results of the analysis of multiple infection carried out in flocks with respiratory signs are probably associated with outbreaks of ornithobacteriosis in turkey flocks in Poland.

An updated comprehensive review on ornithobacteriosis: A worldwide emerging avian respiratory disease

Ornithobacteriosis is an important emerging respiratory disease of domestic and wild birds caused by Ornithobacterium rhinotracheale (ORT) bacterium. The disease has been detected in some countries since 1980, which rapidly spread worldwide later on. Ornithobacteriosis can transmit either horizontally or even vertically. Infection with ORT is mainly characterized by respiratory distress, poor performance, acute death, and a drop in egg production. However, the most characteristic necropsy lesions of dead turkeys and chickens are yoghurt like airsacculitis and pneumonia, usually unilateral. Unfortunately, infection with ORT was misdiagnosed in most of the poultry flocks due to similarity with other respiratory pathogens and the lack of the ideal protocols for diagnosis. Recently, some molecular and serological techniques have been used to detect the infection. Treatment of ORT with antibiotics is very difficult and variable as a result of acquired resistance. Many vaccines have been developed to counteract such infection in broiler, layers, and breeder chicken and turkey flocks. Inactivated, live, and sub-unit vaccines have been used with satisfactory results. Thus, this review paper aimed to address ornithobacteriosis, emphasizing the distribution, transmission, clinical picture, diagnosis, and disease control.

Concurrent infection of Avibacterium paragallinarum and fowl adenovirus in layer chickens

The diagnosis of a concurrent infection of Avibacterium paragallinarum and fowl adenovirus (FAdV) in an infectious coryza–like outbreak in the outskirt of Beijing is reported. The primary signs of the infection were acute respiratory signs, a drop in egg production, and the presence of hydropericardium–hepatitis syndrome–like gross lesions. Laboratory examination confirmed the presence of A. paragallinarum by bacterial isolation and a species-specific PCR test. In addition, conventional serotyping identified the isolates as Page serovar A. Fowl adenovirus was isolated from chicken liver specimen and identified by hexon gene amplification. In addition, histopathologic analysis and transmission electron microscopy examination further confirmed the presence of the virus. Both hexon gene sequencing and phylogenetic analysis defined the viral isolate as FAdV-4. The pathogenic role of A. paragallinarum and FAdV was evaluated by experimental infection of specific-pathogen-free chickens. The challenge trial showed that combined A. paragallinarum and FAdV infection resulted in more severe clinical signs than that by FAdV infection alone. The concurrent infection caused 50% mortality compared with 40% mortality by FAdV infection alone and zero mortality by A. paragallinarum infection alone. To our knowledge, this is the first report of A. paragallinarum coinfection with FAdV. The case implies that concurrent infections with these 2 agents do occur and more attention should be given to the potential of multiple agents during disease diagnosis and treatment.

Genomic Landscape of Ornithobacterium rhinotracheale in Commercial Turkey Production in the United States

Ornithobacterium rhinotracheale is a causative agent of respiratory tract infections in avian hosts worldwide but is a particular problem for commercial turkey production. Little is known about the ecologic and evolutionary dynamics of O. rhinotracheale, which makes prevention and control of this pathogen a challenge. The purpose of this study was to gain insight into the genetic relationships between O. rhinotracheale populations through comparative genomics of clinical isolates from different U.S. turkey producers. O. rhinotracheale clinical isolates were collected from four major U.S. turkey producers and several independent turkey growers from the upper Midwest and Southeast, and whole-genome sequencing was performed. Genomes were compared phylogenetically using single nucleotide polymorphism (SNP)-based analysis, and then assembly and annotations were performed to identify genes encoding putative virulence factors and antimicrobial resistance determinants. A pangenome approach was also used to establish a core set of genes consistently present in O. rhinotracheale and to highlight differences in gene content between phylogenetic clades. A total of 1,457 nonrecombinant SNPs were identified from 157 O. rhinotracheale genomes, and four distinct phylogenetic clades were identified. Isolates clustered by company on the phylogenetic tree, however, and each company had isolates in multiple clades with similar collection dates, indicating that there are multiple O. rhinotracheale strains circulating within each of the companies examined. Additionally, several antimicrobial resistance proteins, putative virulence factors, and the pOR1 plasmid were associated with particular clades and multilocus sequence types, which may explain why the same strains seem to have persisted in the same turkey operations for decades.IMPORTANCE The whole-genome approach enhances our understanding of evolutionary relationships between clinical Ornithobacterium rhinotracheale isolates from different commercial turkey producers and allows for identification of genes associated with virulence, antimicrobial resistance, or mobile genetic elements that are often excluded using traditional typing methods. Additionally, differentiating O. rhinotracheale isolates at the whole-genome level may provide insight into selection of the most appropriate autogenous vaccine strain, or groups of strains, for a given population of clinical isolates.

Comparison of the first Iranian native Ornithobacterium rhinotracheale vaccine with conventional vaccine: A challenge study

Background and Aim:

The best strategy to prevent or control an Ornithobacterium rhinotracheale (ORT) infection is vaccination. The present study aimed to compare the efficacy of the first Iranian inactivated ORT vaccine (Razi, Iran), which had been prepared from a native strain, with the Nobilis ORT Inac (Intervet, The Netherlands) through a challenge trial.

Materials and Methods:

Seventy-two 1-day-old specific pathogen-free White Leghorn chickens were used in this study. The birds were divided randomly into four groups. Following the vaccination and challenge of the birds, the efficacy of the Razi and the Intervet ORT vaccines was evaluated by serological, bacteriological, and molecular methods.

Results:

The antibody titer in vaccinated groups was determined to be significantly higher than unvaccinated birds. In addition, the difference in postmortem lesion scores between the vaccinated and unvaccinated birds was significant. The differences in the means of the antibody titers and postmortem lesion scores in birds that were vaccinated by the Razi and Intervet ORT vaccines were not significant.

Conclusion:

Considering the results of this study, it can be concluded that the Iranian native ORT vaccine was comparable to the Intervet vaccine. The Razi ORT vaccine has effectively decreased the duration of the ORT infection and can effectively protect the chickens against an ORT infection.

Ornithobacterium rhinotracheale: An Update Review about An Emerging Poultry Pathogen

Respiratory diseases in birds generate sanitary and economic impacts and may be related to the environment and climate. Mycoplasma gallisepticum, Ornithobacterium rhinotracheale (ORT), Pasteurella multocida, Avibacterium paragallinarum, Escherichia coli, Riemerella anatipestifer, and Bordetella avium are among the most important avian respiratory pathogens. ORT is responsible for causing ornitobacteriosis, a disease characterized by clinical signs ranging from mild to severe respiratory conditions, with high mortality rates, mainly affecting turkeys and chickens. The first report of ornitobacteriosis was in 1981 in Germany. Despite its importance, few studies on ORT have been published. In addition, the presence of this pathogen has been neglected in poultry farms, mainly due to the lack of appropriate diagnostic protocols. The lack of correct isolation and diagnostic protocols along with inappropriate use of antimicrobial agents have been contributing to treatment failure. Due to its economic importance to the poultry industry, ornitobacteriosis should be monitored and included in national programs for the prevention and control of avian respiratory diseases. This review aimed to update and discuss important issues related to ORT since this pathogen has great economic and sanitary implications for the chicken production chain.