•50 % of the most prevalent virulence genes (>85 %) were toxins/bacteriocin-related.•The most prevalent STs were ST95, ST117, ST390 and ST23.•Application of autogenous vaccine led to lower genetic ...diversity of E. coli.
Colibacillosis is one of the most common problems in the poultry industry. Escherichia coli strains on farms are often genetically diverse and therefore commercial vaccines provide little protection to the flocks. Here, we investigated the effect of the autogenous E. coli vaccines on the prevalence of 84 virulence-associated genes in E. coli isolated from four and five consecutive flocks on two broiler breeder farms, respectively. 115 E. coli isolates were sequenced using Illumina technologies, and compared based on both their set of housekeeping genes and their virulence profiles, defined through the composition of virulence genes. Predominantly, phylogenetic analysis showed obvious distinction between the isolates originating from different farms suggesting spatial-dependent transmission of pathogenic strains. We detected 23 sequence types, while 52.58 % of the isolates belonged to two clonal complexes. Analysis of the virulence genes showed highest prevalence (>85 %) of feoB, uspA, uspB, uspG, uspE, fimH, ompA, astA, focA, hlyE, uspC, crl, csgA, ompT and iss, of which 50 % are toxin associated genes, demonstrating the importance of competition in the pathogenesis process. Interestingly, usp genes, which are primarily associated with uropathogenic E. coli strains, were detected in all investigated isolates. The heatmap analysis demonstrated that strains belonging to same phylogenetic groups often share similar virulence profiles, confirming the usefulness of quick tests for phylogenetic typing. However, our results suggest the need to update the list of the minimal predictors used for the identification of avian pathogenic strains. Overall results indicate that continuous application of autogenous vaccines led to lower genetic diversity of E. coli housekeeping genes, but not virulence genes.
Escherichia coli is the most common bacterial cause of infections in poultry farms. It is known for its genetic heterogenicity that complicates the protection of poultry health through ...immunoprophylaxis. In farms with continuous problems with colibacillosis, autogenous E. coli vaccine was implemented to the vaccination program instead of commercial vaccines. In this study, we investigated the effect of the autogenous vaccine on E. coli phylogroup diversity on 2 broiler breeder farms with 4 and 5 flocks, respectively. The first flocks on both farms were vaccinated with commercial vaccines, while application of autogenous vaccine was introduced in the second flock on both farms. In total, 113 strains were selected based on the target organs and age of chickens. Targeted organs were the peritoneum, liver, oviduct, and bone marrow, and analyzed strains were isolated from chickens older than 21 wk of age when problems with colibacillosis start emerging. The strains were phylotyped by PCR and allocated to phylogroups A, B1, B2, C, D, E, F or clades I–V. The results showed that autogenous vaccine could significantly affect the phylogroup shift of the strains. On farm A, application of the autogenous vaccine induced significantly lower prevalence (P = 0.01) of the phylogroups represented in the vaccine among the strains later isolated from the vaccinated flock, while on farm B, the results showed a decrease in the phylogenetic diversity with a dominant prevalence of group B2 despite the vaccine application. The results indicate that implementation of the autogenous vaccine can repress the majority of the strains, but also be unable to eliminate the presence of certain phylogroups, and thus lead to strain shift. Further detailed analyses of multilocus sequence typing and virulence genes will elucidate the pathogenic potential and selection of certain strains, with emphasis on B2 phylogroup.
Kurthia gibsonii H. Kurth, 1883. Ueber Bacterium zopfii, eine neue Bakterienart. Berichte der Deutschen Botanischen Gesellschaft, 1, 97-100 was isolated on 10 unrelated laying hen farms over a period ...of 15 months. Farmers reported elevated morbidity and mortality rates, and suspected colibacillosis based on the necropsy findings. The most frequently found lesions were perihepatitis, fibrinous peritonitis, salpingitis and oophoritis. Necropsy findings and bacteriological results allowed the diagnosis of colibacillosis. In addition, K. gibsonii was isolated from the ovarian follicles (44.44%), liver (22.22%), peritoneum (16.67%), bone marrow (5.56%), spleen (5.56%), and duodenum (5.56%). On all farms, coinfection with E. coli was detected, while on some farms other common avian pathogens were found as well. In total, 18 K. gibsonii strains were identified and phylogenetically analysed based on the 16S rRNA gene sequences. The results showed some variability of the strains originating from the same farm, although the overall phylogenetic diversity was low, regardless of the geographical location of the farm, age of the flock or date of collection. Embryo lethality assay showed K. gibsonii is not able to cause a primary infection. We conclude that Kurthia gibsonii may play a role as an opportunistic pathogen for poultry. This is the first report of coinfection of Kurthia gibsonii and E. coli in laying hens.
RESEARCH HIGHLIGHTS
Kurthia gibsonii is a novel opportunistic pathogen in poultry.
Phylogenetic analysis showed low genetic diversity of Kurthia gibsonii isolates.
Embryo lethality assay showed K. gibsonii does not cause primary infections.
Fowl typhoid is a septicemic disease caused by
subsp.
serovar Gallinarum biovar Gallinarum. It is a host-specific disease primarily affecting chickens and turkeys, although it has been reported in ...various animal species and sporadically in humans. Here, we present a case of a fowl typhoid outbreak on a turkey poult farm where the source of infection was the hatchery. The birds started showing symptoms of growth retardation at 21 days of age, after which the mortality rates gradually started to increase. Post mortem examination revealed that the main lesions were granulomatous proliferations in the small intestines. The results of the histopathological examination indicate that the severity of the infection was alleviated by the application of phytogenic mixtures and probiotics as a supportive treatment, even though the affected flock was eventually culled at 60 days of age. The farmer was advised to apply more strict biosecurity measures to prevent the spread of the disease on the farm and try to eradicate the pathogen from the barn. Since the outbreak, there have been no recurrent infections.
The black soldier fly (Hermetia illucens) has emerged as an interesting alternative protein source in animal feed due to its ability to grow on various substrates. Although it has many rearing ...benefits and possible applications, it has an unfavourable fatty acid profile if used for human consumption due to its high content of lauric acid and low content of polyunsaturated fatty acids. In order to investigate whether the lipid composition of black soldier fly larvae can be altered, the feeding media were supplemented with varying concentrations of fish, linseed or coconut oil (1, 2.5 and 5%). Two-week-old larvae were collected, measured and their tissue fatty acid composition was determined. The fatty acid profile of the larvae showed significant plasticity, depending on the life stage and the fatty acid composition of the feeding media. The addition of 2.5 and 5% of different oils significantly changed the fatty acid composition of larvae, depending on the type and percentage of oil. The n6/n3 ratio was considerably improved by supplementing fish and linseed oil. The addition of linseed oil increased the content of linolenic acid, but bioconversion to eicosapentaenoic and docosahexaenoic acids was low. In contrast, the addition of fish oil significantly increased the content of eicosapentaenoic and docosahexaenoic acids in the larvae. The content of lauric acid significantly increased after coconut addition. The trial showed that by using different oils, the lipid composition of black soldier fly larvae could be specifically changed to increase the beneficial long chain n3 polyunsaturated fatty acids, and the amount of lauric or linolenic acid.
is the main bacterial cause of major economic losses and animal welfare issues in poultry production. In this study, we investigate the effect of an autogenous vaccine on
strains longitudinally ...isolated from broiler breeder flocks on two farms. In total, 115
isolates were sequenced using Illumina technologies, and compared based on a single-nucleotide polymorphism (SNP) analysis of the core-genome and antimicrobial resistance (AMR) genes they carried. The results showed that SNP-based phylogeny corresponds to a previous multilocus-sequence typing (MLST)-based phylogeny. Highly virulent sequence types (STs), including ST117-F, ST95-B2, ST131-B2 and ST390-B2, showed a higher level of homogeneity. On the other hand, less frequent STs, such as ST1485, ST3232, ST7013 and ST8573, were phylogenetically more distant and carried a higher number of antimicrobial resistance genes in most cases. In total, 25 antimicrobial genes were detected, of which the most prevalent were
(
) (100%),
(71.3%) and
(
) (13.91%). The frequency of AMR genes showed a decreasing trend over time in both farms. The highest prevalence was detected in strains belonging to the B1 phylogenetic group, confirming the previous notion that commensal strains act as reservoirs and carry more resistance genes than pathogenic strains that are mostly associated with virulence genes.
Escherichia coli (E. coli) is one of the most common bacterial causes of infection in poultry farming. Whether the infection is localized or systemic, a primary or secondary disease, it is most ...frequently treated through the application of wide-spectrum antimicrobials. Excessive use of antimicrobials in agriculture is significantly contributing to the worldwide rise of antimicrobial resistance, but is also very expensive and often ineffective in the long term. Here, we present a case where a colibacillosis outbreak on a family farm of laying hens was treated using an autogenous vaccine. The birds had septicemia, cellulitis, and severe skin wounds. They were not vaccinated against E. coli, and did not receive any antimicrobials previously. E. coli strains were isolated from the daily mortalities on the farm and used for preparation of the vaccine. Each bird was given an intramuscular injection of the autogenous vaccine. The immunogenicity of the vaccine was tested by the determination of specific antibody levels in the sera of the birds using the in-house ELISA. Shortly after vaccination, the morbidity and mortality rates significantly decreased, and egg production was improved. The application of the autogenous vaccine served as a curative and preventive measure, and has proven to be a very efficient method of antimicrobial therapy.
Mycoplasma synoviae (MS), despite its lower pathogenicity, has the ability to cause significant losses in poultry production but is usually underdiagnosed. In egg layer production, losses could be ...significant because of the drop in egg production and poor eggshell quality. Problems with colibacillosis and other infections secondary to MS have been continuously reported on Croatian egg layer farms. As a result, regular monitoring of flocks also included screening of the seroprevalence and molecular detection of MS using ELISA and qPCR tests, respectively. During monitoring, altogether 1135 samples were tested, including 1067 serum samples and 68 tracheal swabs, in a total of 126 flocks and 83 longitudinally merged flocks on 15 farms during the period from 2017 to 2021. The results showed a high general prevalence of MS with 86.6% positive layer farms, while grouped flock seroprevalence and prevalence were 98.6% and 85.7%, respectively. With age, seroprevalence and ELISA titers rise significantly compared to the rearing period, with a significant mutual correlation over the entire production period. Additionally, there is a significant correlation between ELISA titers and age in weeks. Several flocks covered longitudinally from the first week of age, over the rearing period to the end of production, showed low prevalence during the rearing period, with a later significant rise in titer and prevalence, which indicates the dominance of horizontal transmission during production. Overall results indicate the need for a prompt reaction regarding preventive measures, such as better flock management, biosecurity and vaccination, which would reduce the losses and improve production. Key words: Mycoplasma synoviae; layer flocks; seroprevalence; ELISA; molecular detection; qPCR Mycoplasma synoviae (MS), unatoc nizoj patogenosti, moze uzrokovati znacajne gubitke u proizvodnji peradi, no obicno je poddijagnosticirana. Gubici u proizvodnji konzumnih jaja mogu biti znacajni zbog pada proizvodnje i lose kvalitete ljuske jajeta. Problemi s kolibacilozom i drugim zarazama koje se javljaju kao sekundarne MS-u kontinuirano se prijavljuju na farmama nesilica konzumnih jaja u Hrvatskoj. Stoga je u pracenje zdravlja na farmama ukljuceno i otkrivanje seroprevalencije i molekularnog dokaza MS-a primjenom ELISA i qPCR testova. Tijekom pracenja testirano je ukupno 1135 uzoraka, 1067 seruma i 68 obrisaka dusnika, u ukupno 126 jata, odnosno 83 longitudinalno grupiranih jata na 15 farmi od 2017. do 2021. godine. Rezultati su pokazali visoku opcu prevalenciju od 86,6% pozitivnih farmi na MS. Kod longitudinalno grupiranih jata seroprevalencija je iznosila 98,6%, dok je molekularnim monitoringom prevalencija bila 85,7%. S dobi, seroprevalencija i ELISA titar znacajno rastu, uz znacajnu medusobnu korelaciju tijekom cijelog razdoblja proizvodnje. Takoder, postoji znacajna korelacija izmedu ELISA titra i dobi u tjednima. Jata pracena longitudinalno od dobi jednog tjedna do kraja proizvodnje, pokazuju nisku prevalenciju tijekom uzgojnog razdoblja. Kasnije, u razdoblju proizvodnje, dolazi do znacajnog porasta titra i prevalencije, sto ukazuje na dominantan horizontalni prijenos tijekom proizvodnje. Rezultati monitoringa skrecu pozornost na potrebu brze reakcije na farmama s ciljem poboljsanja preventivnih mjera, narocito boljeg upravljanja jatima, biosigurnosnih mjera i cijepljenja, sto bi znacajno smanjilo gubitke i poboljsalo proizvodnju. Kljucne rijeci: Mycoplasma synoviae; kokosi nesilice; seroprevalencija; ELISA; prevalencija; qPCR
Gallibacterium anatis is considered one of the most common bacterial causative agents of reproductive tract disorders in poultry. In this study, phylogenetic analysis of partial rpoB sequences and ...biotyping using MALDI-TOF MS was done in order to investigate the genetic diversity of Gallibacterium isolates from 13 farms with different biosecurity measures and management practices. Sampling was done as a part of regular monitoring, except for Farms 9-13 that were included in the study to represent extensive production systems with lowest biosecurity levels. Pharyngeal and cloacal swabs were taken from live birds, while swabs from trachea, liver, peritoneum and oviduct were taken during necropsies. After cultivation and identification, strains from each farm were randomly selected for sequencing and biotyping. Both results showed high level of heterogeneity among the isolates originating from farms with low biosecurity levels, unlike isolates from farms with higher biosecurity levels and proper management that were more closely related and clustered together. Such correlation was statistically significant. Low biosecurity levels enable horizontal transmission of the pathogens, as well as gene transfer. The results confirm the importance of adequate biosecurity measures and management on poultry farms as they greatly affect the genetic diversity of the pathogens. Therefore, implementation of basic biosecurity measures could help control the heterogeneity of Gallibacterium strains, which would alleviate control of the infection prevalence on farms through immunoprophylaxis, and consequently improve poultry production. Also, the genetic diversity of G. anatis on poultry farms could be a good bioindicator of management practices and biosecurity measures used.
RESEARCH HIGHLIGHTS
High correlation between low biosecurity and high diversity of Gallibacterium anatis.
Diversity of Gallibacterium is a good bioindicator of management practices on farms.
is considered one of the most common bacterial causative agents of reproductive tract disorders in poultry. In this study, phylogenetic analysis of partial
sequences and biotyping using MALDI-TOF MS ...was done in order to investigate the genetic diversity of
isolates from thirteen farms with different biosecurity measures and management practices. Sampling was done as a part of regular monitoring, except for Farms 9-13 that were included in the study to represent extensive production system with lowest biosecurity levels. Pharyngeal and cloacal swabs were taken from live animals, while swabs from trachea, liver, peritoneum and oviduct were taken during necropsies. After cultivation and identification, strains from each farm were randomly selected for sequencing and biotyping. Both results showed high level of heterogeneity among the isolates originating from farms with low biosecurity levels, unlike isolates from farms with higher biosecurity levels and proper management that were more closely related and clustered together. Such correlation was statistically significant. Low biosecurity levels enable horizontal transmission of the pathogens, as well as gene transfer. The results confirm the importance of adequate biosecurity measures and management on poultry farms as they greatly affect the genetic diversity of the pathogens. Therefore, implementation of basic biosecurity measures could help control the heterogeneity of
strains, which would alleviate control of the infection prevalence on farms through immunoprophylaxis and consequently improve poultry production. Also, the genetic diversity of
on poultry farms could be a good bioindicator of management practice and biosecurity measures used.
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