Prevalence, Risks and Antibiotic Resistance of Salmonella in Poultry Production Chain

Salmonella spp. are bacteria that cause salmonellosis, a common form of foodborne illness with major impact on human health and huge financial losses in poultry industry. The incidence of notified cases of salmonellosis has declined from a peak of 24 per 100,000 in 2009 to 20.4 reported cases per 100,000 population in 2013, with S. enteritidis and S. typhimurium being the most commonly reported serovar in EU. Salmonella spp. has been detected in a range of foods, and outbreaks have predominantly been associated with animal products such as eggs, poultry and dairy products, but also with plant origin food such as salad dressing, fruit juice and sesame. At the time of slaughter, Salmonella-infected poultry may have high numbers of organisms in their intestines as well as on the outside of the bird and are therefore an important source of contamination. Nowadays, food safety has become an important concern for the European society and governments; therefore, more strict and harmonized regulations are being implemented throughout the poultry production chain with the aim to guarantee and increase the consumer confidence in foodstuffs of animal origin. Furthermore, increasing antimicrobial resistance in non-typhoid Salmonella species has been a serious problem for public health worldwide

An Assessment of the Level of Protection Against Colibacillosis Conferred by Several Autogenous and/or Commercial Vaccination Programs in Conventional Pullets upon Experimental Challenge

The prevention of avian colibacillosis has historically been investigated through vaccination, with variable outcomes. Commercial live (attenuated) and inactivated vaccines are reported to have limited efficacy in the context of heterologous challenge. Autogenous vaccination, using field isolates, is widely used, but scarcely documented. Different vaccination programs, including a live commercial vaccine and/or an inactivated autogenous vaccine, were compared for three different avian pathogenic Escherichia coli (APEC) strain (serotypes O78, O18 and O111) challenges. On the pullet farm, four groups of conventional pullets received different vaccination protocols. Group A was kept unvaccinated (control group). Group B was vaccinated three times with a live commercial O78 E. coli vaccine (at one day old, 59 and 110 days of age). Group C was immunized twice (at 79 and 110 days) with a three-valence autogenous vaccine (O78, O18 and O111). Group D was vaccinated first with the commercial vaccine (at one day old and 59 days), then with the autogenous vaccine (110 days). Birds were transferred to the experimental facility at 121 days of age and were challenged 10 days later. In each group, 20 birds were challenged with one of the three APEC strains (O78, O18, O111); in total, 80 birds were challenged by the same strains (20 per group). The recorded outcomes were: mortality rate, macroscopic lesion score in target organs and the bacterial recovery of the challenge strain from bone marrow and pooled organs. When challenged with O78 or O111 strains, birds from groups C and D proved to be significantly better protected, in terms of lesion scoring and bacteriological isolation, than those of groups A and B. With the O18 challenge, only birds of group D presented a statistically significant reduction of their lesion score. To the authors' knowledge, this is the first report on the efficacy of an immunization program in poultry that combines commercial and autogenous vaccines

infectious bronchitis virus gel vaccination evaluation of mass like b 48 and 793 b like 1 96 vaccine kinetics after combined administration at 1 day of age

ABSTRACT Infectious bronchitis (IB) control has a strong impact on poultry farming, because of the necessary epidemiological knowledge for planning the best strategy, the optimal strain association, the priming and boosting interventions. Broiler farming is even more problematic given the short and intense productive cycle, which requires an early onset of protection against most of the infectious threats, possibly with limited respiratory post-vaccination reactions that would have a direct impact on the bird health and productivity. For this purpose, gel vaccination has been proposed as a new approach for infectious bronchitis virus (IBV) control and vaccine intake, kinetics and compatibility of combined strains administered by gel have been analyzed in this study. After gel vaccination with single and combined 1/96 and B-48 strains on 4 groups of commercial broilers, a 21-d-long experimental trial has been conducted to monitor the vaccine safety by clinical assessment and vaccine kinetics by strain-specific real-time RT-PCR on choanal cleft swabs. The vaccine strains administered by gel were safe and negligible respiratory signs were detected, even when combined. Vaccine titers were compared among groups and within the same group among a 10-bird pooled sample and 10 swabs from individually sampled birds. 1/96 strain early reached high titers in all animals, while B-48 presence was less constant even though it was detected in almost all birds before the trial end. The individual and pooled sample comparison revealed a partial overestimation of vaccine titers in the pooled samples and the loss of the prevalence data, although the trend portrayed by the pooled swabs closely followed the individual ones

Infectious bursal disease virus in Western Europe: the rise of reassortant strains as the dominant field threat

Infectious bursal disease virus (IBDV) is a highly contagious birnavirus causing a burdensome immunosuppressive disease in chickens. IBDV features a remarkable antigenic, pathogenic and genetic heterogeneity, with significant implications on disease manifestation, control measures and diagnostic approaches. The recent proposals of comprehensive phylogenetic classification systems offered the ideal platform for large-scale molecular surveys, which are crucial to gather epidemiological data and inform control efforts. In this study, the IBDV scenario was investigated in most of Western Europe by considering the results of diagnostic activities performed internationally throughout 2021. In total, 470 bursal samples from nine different countries were analysed by RT-PCR targeting the VP2. When a field virus was identified, the VP1 was also characterized. Most of the 132 detected field viruses were highly homologous reassortants featuring a very virulent-like VP2 and a classical-like VP1 (genotype A3B1). Despite emerging recently, these reassortants were already signalled in several countries in North-Western Europe and associated with subclinical infections. Here, we report their further spread in the region, where they currently represent the dominant field threat. Two other IBDV types were found, one in Italy, where all the identified viruses clustered in a clade of the A3B1 genotype previously reported only in Russia and the Middle East, and the other in Portugal, where the recently characterized A9B1 genotype was confirmed to circulate. The obtained data suggest the recent occurrence of a major shift in the Western European epidemiological landscape of IBDV, stressing the importance of steady monitoring and sharing of information among different countries and laboratories

Investigation of Serotype Prevalence of <em>Escherichia coli</em> Strains Isolated from Layer Poultry in Greece and Interactions with Other Infectious Agents

Colibacillosis is the most common bacterial disease in poultry and it is caused by avian pathogenic Escherichia coli (APEC), which is assigned to various O-serogroups. Previous studies have shown that APEC strains are more often related to certain O-serogroups such asO78, O2 and O1. E. coli has been reported to act either as a primary or secondary agent in complicating other infections. The aim of this study was to investigate the occurrence of and characterize the O-serogroups of E. coli strains isolated from commercial layer and layer breeder flocks showing macroscopic lesions of colibacillosis and increased or normal mortality in Greece. Furthermore, we attempted to assess the interaction between infectious agents such as Mycoplasma gallisepticum (MG), Mycoplasma synoviae (MS), infectious bronchitis (IBV) and infectious laryngotracheitis (ILT) with E. coli infections in layer flocks with increased mortality. Our study revealed that in addition to the common serogroups (O78, O2), many other, and less common serogroups were identified, including O111. The O78, O111 and O2 serogroups were frequently detected in flocks with lesions of colibacillosis and increased mortality whereas O2, O88 and O8 were reported more commonly in birds with colibacillosis lesions but normal mortality rates. These data provide important information for colibacillosis monitoring and define preventative measures, especially by using effective vaccination programs because E. coli vaccines are reported to mainly offer homologous protection. Finally, concerning the association of the four tested infectious agents with E. coli mortality, our study did not reveal a statistically significant effect of the above infectious agents tested with E. coli infection mortality

First Report of Avian Metapneumovirus Subtype B Field Strain in a Romanian Broiler Flock during an Outbreak of Respiratory Disease

Avian metapneumovirus (aMPV) represents one of the most prevalent diseases of Turkey, especially in combination with other pathogens, and its frequency is also increasing among chickens. Despite this evidence, epidemiologic data are poor and scattered, severely preventing control of the disease even in highly developed areas such as Europe. In the present study, the detection and characterization of an aMPV subtype B strain circulating in a vaccinated but symptomatic Romanian broiler flock is reported for the first time. The phylogenetic analysis based on the partial G gene sequence demonstrates the close relationship of the Romanian virus with a group of recently emerged Italian field strains for which vaccine-induced protection was experimentally proven to be partial. These preliminary results allow us to hypothesize the spreading of vaccine-escaping aMPV subtype B strains through Europe and, consequently, dictate the carrying out of a more systematic survey to confirm this theory and enforce adequate countermeasures

Antimicrobial Resistance, FlaA Sequencing, and Phylogenetic Analysis of Campylobacter Isolates from Broiler Chicken Flocks in Greece

Human campylobacteriosis caused by thermophilic Campylobacter species is the most commonly reported foodborne zoonosis. Consumption of contaminated poultry meat is regarded as the main source of human infection. This study was undertaken to determine the antimicrobial susceptibility and the molecular epidemiology of 205 Campylobacter isolates derived from Greek flocks slaughtered in three different slaughterhouses over a 14-month period. A total of 98.5% of the isolates were resistant to at least one antimicrobial agent. In terms of multidrug resistance, 11.7% of isolates were resistant to three or more groups of antimicrobials. Extremely high resistance to fluoroquinolones (89%), very high resistance to tetracycline (69%), and low resistance to macrolides (7%) were detected. FlaA sequencing was performed for the subtyping of 64 C. jejuni and 58 C. coli isolates. No prevalence of a specific flaA type was observed, indicating the genetic diversity of the isolates, while some flaA types were found to share similar antimicrobial resistance patterns. Phylogenetic trees were constructed using the neighbor-joining method. Seven clusters of the C. jejuni phylogenetic tree and three clusters of the C. coli tree were considered significant with bootstrap values &gt;75%. Some isolates clustered together were originated from the same or adjacent farms, indicating transmission via personnel or shared equipment. These results are important and help further the understanding of the molecular epidemiology and antimicrobial resistance of Campylobacter spp. derived from poultry in Greece

The Effect of Whey on Performance, Gut Health and Bone Morphology Parameters in Broiler Chicks

Whey is a highly nutritious byproduct of the cheese industry that can be used effectively in the animal feed industry. However, the use of whey in poultry diets is limited by its high lactose and mineral contents. The objective of the present study was to evaluate the effect of different concentrations of whey in poultry diets on the performance, intestinal microbiota and physico-chemical parameters of the intestinal ecosystem, as well as on the bone morphology and its strength in broiler chicks. One hundred and twenty-eight, day-old, male broiler chicks were randomly allocated into four treatment groups of 32 chicks each. The treatment groups were: group A, which served as negative control and groups B, C and D, supplemented with 1, 2 and 5% of dietary whey, respectively. Performance of the groups was evaluated throughout the experiment. Following necropsies, the gastrointestinal tract from each bird was removed, divided into its anatomical parts and intestinal samples were taken for microbiological analysis and for pH and viscosity measurement as well. Tibiotarsus was also collected for morphometric analysis and strength evaluation. The statistical analysis of the experimental data revealed that the dietary supplementation of 1 and 2% of whey improved significantly (p &le; 0.05) the body weight, while the addition of 5% of whey reduced significantly (p &le; 0.05) the body weight. Furthermore, the addition of 1, 2 and 5% of dietary whey increased significantly (p &le; 0.05) the pH of jejunum digesta and reduced significantly (p &le; 0.05) the pH of caecum digesta compared to the control group. The addition of 1 and 2% of whey reduced significantly (p &le; 0.05) the viscosity in the jejunum and ileum digesta, compared to the addition of 5% of whey which reduced significantly (p &le; 0.05) the viscosity in jejunum digesta but increased significantly (p &le; 0.05) the viscosity in ileum digesta. Moreover, the addition of 1, 2 and 5% of dietary whey increased significantly (p &le; 0.05) the caecal counts of Lactobacillus spp. and Lactococcus lactis, while the addition of 5% of whey reduced significantly (p &le; 0.05) the tibiotarsus length. It can be concluded that the addition of low quantities of whey up to 2% promoted the performance and gut health of birds, while the addition of higher quantities of whey at the level of 5% had a detrimental effect on the performance and tibiotarsus length