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Vaccines Apr 2023Pullorum disease, caused by the serovar Gallinarum biovar Pullorum, is a highly contagious disease in the poultry industry, leading to significant economic losses in...
Pullorum disease, caused by the serovar Gallinarum biovar Pullorum, is a highly contagious disease in the poultry industry, leading to significant economic losses in many developing countries. Due to the emergence of multidrug-resistant (MDR) strains, immediate attention is required to prevent their endemics and global spreading. To mitigate the prevalence of MDR infections in poultry farms, it is urgent to develop effective vaccines. Reverse vaccinology (RV) is a promising approach using expressed genomic sequences to find new vaccine targets. The present study used the RV approach to identify new antigen candidates against Pullorum disease. Initial epidemiological investigation and virulent assays were conducted to select strain R51 for presentative and general importance. An additional complete genome sequence (4.7 Mb) for R51 was resolved using the Pacbio RS II platform. The proteome of was analyzed to predict outer membrane and extracellular proteins, and was further selected for evaluating transmembrane domains, protein prevalence, antigenicity, and solubility. Twenty-two high-scored proteins were identified among 4713 proteins, with 18 recombinant proteins successfully expressed and purified. The chick embryo model was used to assess protection efficacy, in which vaccine candidates were injected into 18-day-old chick embryos for in vivo immunogenicity and protective effects. The results showed that the PstS, SinH, LpfB, and SthB vaccine candidates were able to elicit a significant immune response. Particularly, PstS confers a significant protective effect, with a 75% survival rate compared to 31.25% for the PBS control group, confirming that identified antigens can be promising targets against infection. Thus, we offer RV to discover novel effective antigens in an important veterinary infectious agent with high priority.
PubMed: 37112777
DOI: 10.3390/vaccines11040865 -
Genes Mar 2023Gallinarum (SG) is the causative agent of fowl typhoid (FT), a disease that is harmful to the poultry industry. Despite sanitation and prophylactic measures, this...
Gallinarum (SG) is the causative agent of fowl typhoid (FT), a disease that is harmful to the poultry industry. Despite sanitation and prophylactic measures, this pathogen is associated with frequent disease outbreaks in developing countries, causing high morbidity and mortality. We characterized the complete genome sequence of Colombian SG strains and then performed a comparative genome analysis with other SG strains found in different regions worldwide. Eight field strains of SG plus a 9R-derived vaccine were subjected to whole-genome sequencing (WGS) and bioinformatics analysis, and the results were used for subsequent molecular typing; virulome, resistome, and mobilome characterization; and a comparative genome study. We identified 26 chromosome-located resistance genes that mostly encode efflux pumps, and point mutations were found in gyrase genes ( and ), with the mutation S464T frequently found in the Colombian strains. Moreover, we detected 135 virulence genes, mainly in 15 different pathogenicity islands (SPIs). We generated an SPI profile for SG, including C63PI, CS54, ssaD, SPI-1, SPI-2, SPI-3, SPI-4, SPI-5, SPI-6, SPI-9, SPI-10, SPI-11, SPI-12, SPI-13, and SPI-14. Regarding mobile genetic elements, we found the plasmids Col(pHAD28) and IncFII(S) in most of the strains and 13 different prophage sequences, indicating a frequently obtained profile that included the complete phage Gifsy_2 and incomplete phage sequences resembling Escher_500465_2, Shigel_SfIV, Entero_mEp237, and Salmon_SJ46. This study presents, for the first time, the genomic content of Colombian SG strains and a profile of the genetic elements frequently found in SG, which can be further studied to clarify the pathogenicity and evolutionary characteristics of this serotype.
Topics: Animals; Colombia; Typhoid Fever; Genetic Profile; Salmonella Infections, Animal; Salmonella; Genomics
PubMed: 37107581
DOI: 10.3390/genes14040823 -
Animals : An Open Access Journal From... Apr 2023Fowl typhoid, a septicaemic disease of poultry, is caused by Gallinarum and leads to severe economic losses. The aim of the present study was to isolate, select and...
Fowl typhoid, a septicaemic disease of poultry, is caused by Gallinarum and leads to severe economic losses. The aim of the present study was to isolate, select and characterize indigenous probiotic lactobacilli with anti- Gallinarum activity. A total 55 lactobacilli were isolated from the caeca and ileum parts of healthy chickens and identified to species level by 16S rDNA sequencing. All the isolates were initially screened for antimicrobial activity and selected isolates were further subjected to in vitro evaluation of probiotic properties. Lactobacilli isolates ( = 21) showed varying levels of activity (08-18 mm) against Gallinarum. These selected isolates also showed tolerance to acidic conditions (pH 3 and 4). Out of these 21 isolates, 13 showed growth (>0.5 OD at 600 nm) 0.3% bile salts. Moreover, these isolates also had the ability of auto-aggregation (20.05 ± 0.62%-50.70 ± 1.40%), and co-aggregation with Gallinarum (5.22 ± 0.21%-42.07 ± 0.70%). Results revealed that lactobacilli had a higher level of resistance to vancomycin (100%), streptomycin (100%), ciprofloxacin (95%), gentamicin (90%), doxycycline (90%), oxytetracycline (85%), and bacitracin (80%), and a lower level of resistance to penicillin (33%), erythromycin (28%), chloramphenicol (23%), fusidic acid (23%) and amoxicillin (4%). The PC-10 and PC-76 were sensitive to most of the antibiotics. The overall results revealed that two strains (PC-10 and PC-76) fulfill the in vitro selection criteria of probiotics, i.e, tolerance to low pH, resistance to bile salts, auto-aggregation, co-aggregation with Gallinarum, and absence of acquired antibiotic resistance. The PC-10 and PC-76 also inhibited the (>5 log10) growth of Gallinarum in co-culture assay. It is concluded that PC-10 and PC-76 may be further investigated and developed as anti- Gallinarum probiotics for poultry.
PubMed: 37106847
DOI: 10.3390/ani13081284 -
Mobile DNA Apr 2023Antimicrobial resistant pathogens are a global health threat driven by the indiscriminate use of antimicrobials. Antimicrobial resistance can be acquired by resistance...
Antimicrobial resistant pathogens are a global health threat driven by the indiscriminate use of antimicrobials. Antimicrobial resistance can be acquired by resistance genes encoded by mobile genetic elements. In this study, we identified a strain of Salmonella enterica serovar Gallinarum (SG4021) from an infected chicken in Korea and characterized the presence of resistance genes in its plasmid by whole genome sequencing. The sequence was then compared with that of a plasmid (P2) from strain SG_07Q015, the only other strain of S. Gallinarum isolated in Korea for which a genome sequence is available. The results revealed that both strains harbored nearly identical DNA carrying antibiotic resistance gene cassettes inserted into integron In2 of the transposable element Tn21, namely an aadA1 resistance gene conferring resistance to aminoglycosides and a sul1 resistance gene conferring resistance to sulfonamide. Interestingly, despite the presence of sul1 in SG4021, an antibiotic sensitivity test revealed that it was sensitive to sulfonamides. Further analysis revealed that this disparity was due to the insertion of a ~ 5 kb ISCR16 sequence downstream of the promoter driving sul1 expression in SG4021. Using various mutants, we showed that the insertion of ISCR16 blocked the expression of the sul1 gene from the upstream promoter. Therefore, the functionality of antimicrobial resistance genes determines phenotypic antimicrobial resistance.
PubMed: 37095552
DOI: 10.1186/s13100-023-00292-8 -
Journal of Animal Science and Technology Mar 2023The poultry industry, which produces excellent sources of protein, suffers enormous economic damage from diseases. To solve this problem, research is being conducted on...
The poultry industry, which produces excellent sources of protein, suffers enormous economic damage from diseases. To solve this problem, research is being conducted on the early detection of infection according to the behavioral characteristics of poultry. The purpose of this study was to evaluate the potential of a non-movement behavior observation method to detect sick chickens. Forty 1-day-old Ross 308 males were used in the experiments, and an isolator equipped with an Internet Protocol (IP) camera was fabricated for observation. The chickens were inoculated with serovar A18-GCVP-014, the causative agent of fowl typhoid (FT), at 14 days of age, which is a vulnerable period for FT infection. The chickens were continuously observed with an IP camera for 2 weeks after inoculation, chickens that did not move for more than 30 minutes were detected and marked according to the algorithm. FT infection was confirmed based on clinical symptoms, analysis of cardiac, spleen and liver lesion scores, pathogen re-isolation, and serological analysis. As a result, clinical symptoms were first observed four days after inoculation, and dead chickens were observed on day six. Eleven days after inoculation, the number of clinical symptoms gradually decreased, indicating a state of recovery. For lesion scores, dead chickens scored 3.57 and live chickens scored 2.38. Pathogens were re-isolated in 37 out of 40 chickens, and hemagglutination test was positive in seven out of 26 chickens. The IP camera applied with the algorithm detected about 83% of the chickens that died in advance through non-movement behavior observation. Therefore, observation of non-movement behavior is one of the ways to detect infected chickens in advance, and it appears to have potential for the development of remote broiler management system.
PubMed: 37093929
DOI: 10.5187/jast.2022.e105 -
Developmental and Comparative Immunology Aug 2023In the present study, lipid-A gene mutants of Salmonella gallinarum (SG) were screened, and the arnT mutant exhibited optimal acidic and oxidative-stress and...
Screening of lipid-A related genes and development of low-endotoxicity live-attenuated Salmonella gallinarum by arnT deletion that elicits immune responses and protection against fowl typhoid in chickens.
In the present study, lipid-A gene mutants of Salmonella gallinarum (SG) were screened, and the arnT mutant exhibited optimal acidic and oxidative-stress and macrophage-survival. Modifying lipid-A by arnT-deletion resulted in significantly reduced endotoxicity, virulence, and mortality. Therefore, the arnT-deleted vaccine-candidate strain JOL2841 was constructed and demonstrated to be safe due to appropriate clearance by the chicken immune system. The reduced-endotoxicity of JOL2841 was evident from the downregulation of TNFα and IL-1β inflammatory cytokines, no inflammatory signs in organ gross-examination, and histopathological analysis. The IgY and IgA antibody titres, CD4, and CD8 T-cell population improvements, and IL-4, IL-2, and INFγ expression decipher the profound Th2 and Th1 immunogenicity. Consequently, JOL2841 exhibited prominent protection against wild-type SG challenge, as revealed by organ pathogen-load determination, organ gross-examination, and histopathological examination. Overall, the study represented the first report of arnT deficient SG resulted in negligible endotoxicity, low-virulence, safety and coordinated elicitation of humoral and cell-mediated immune response in chickens.
Topics: Animals; Chickens; Endotoxins; Typhoid Fever; Salmonella Vaccines; Poultry Diseases; Salmonella Infections, Animal; Salmonella; Immunity, Cellular; Lipids; Vaccines, Attenuated
PubMed: 37044268
DOI: 10.1016/j.dci.2023.104707 -
Journal of Microbiological Methods May 2023The poultry industry in developing countries is still combating mortality and economic loss due to Salmonella contamination. Salmonella Gallinarum is a common pathogen...
The poultry industry in developing countries is still combating mortality and economic loss due to Salmonella contamination. Salmonella Gallinarum is a common pathogen of poultry birds, being the etiologic agent of fowl typhoid, which specifically infects adult birds via the oral-fecal route. Timely detection of S. Gallinarum in poultry flocks can allow early treatment intervention leading to a decrease in economic losses. Detection of S. Gallinarum is challenging, while its PCR-based detection is a promising strategy, however, due to its high genomic similarity with other commonly existing Salmonella spp., identification of S. Gallinarum from poultry samples with high specificity is still a challenge. The current study was conducted to isolate S. Gallinarum from different districts of Pakistan, assess their antibiotic susceptibility profile, and develop a method for its early detection. A total of 20 strains were isolated using buffer peptone water, selenite cysteine broth, and Xylose Lysine Tergitol-4 (XLT-4) agar supplemented with tergitol and characterized by biochemical procedures. The antibiotic sensitivity profile highlighted the highest resistance of isolates towards novobiocin and nalidixic acid, commonly used antibiotics in Pakistan Poultry production. The primers designed to amplify a unique genomic region of S. Gallinarum, showed successful detection of twenty S. Gallinarum strains, while no amplification with genomic DNA from other common Salmonella spp. The reported method can be utilized to detect S. Gallinarum from tissue samples of infected birds in a short time leading to early diagnosis and timely treatment intervention.
Topics: Animals; Poultry; Pakistan; Poloxalene; Poultry Diseases; Salmonella; Birds; Polymerase Chain Reaction; Drug Resistance, Microbial; Anti-Bacterial Agents; Early Diagnosis; Salmonella Infections, Animal; Chickens
PubMed: 37015313
DOI: 10.1016/j.mimet.2023.106709 -
Journal of Microbiological Methods Apr 2023Salmonella species are Gram-negative bacteria with more than 2600 serovars. Among these serovars, many are associated with various diseases in livestock and humans....
Salmonella species are Gram-negative bacteria with more than 2600 serovars. Among these serovars, many are associated with various diseases in livestock and humans. White Kauffman Le-Minor (WKL) serotyping scheme applies specific serum to determine the serovars of Salmonella. Recent studies have applied molecular methods for serovar predictions. These methods include PCR, hybridization and sequence data to detect/predict serovar-specific genetic elements. Among these, PCR is a robust method if the unique genetic element is already known. Within this context, also involving novel primers, two multiplex PCR assays were standardized to detect six important Salmonella serovars viz. Typhimurium, Enteritidis, Kentucky, Infantis, Virchow and Gallinarum associated with poultry in India. The developed PCR assays showed targeted serovar specificity. Serial dilution experiments of both kit-based and crude lysate DNA preparations indicated similar applicability of both methods for testing from pure cultures. Further the developed assays were validated with 25 recent field isolates to confirm the applicability in routine diagnosis. The PCR assay could predict all the targeted serovars (17/25) with 100% specificity (CI-95%; 0.63-1). Molecular serotyping can reduce the number of serum used in comparison to the conventional serotyping which involves more random application of serum.
Topics: Animals; Humans; Serotyping; Serogroup; Multiplex Polymerase Chain Reaction; Poultry; Salmonella enterica; Salmonella
PubMed: 37003300
DOI: 10.1016/j.mimet.2023.106710 -
Tropical Animal Health and Production Mar 2023Fowl typhoid (FT) is an economically significant bacterial disease of layers leading to a drastic drop in egg production. Due to increased public health concerns about...
Fowl typhoid (FT) is an economically significant bacterial disease of layers leading to a drastic drop in egg production. Due to increased public health concerns about antibiotics in poultry feed, a search for new safe antimicrobials for treating fowl typhoid is crucial. The antimicrobial effect of cinnamaldehyde essential oil (CnEO) against fowl typhoid in layers was investigated in this experiment. The 60-week-old BV300-layer birds (n = 100) were divided into five groups: the non-challenged control group A, only cinnamaldehyde-treated group B (CnEO @ 1:8000 dilutions through drinking water for 60 days), the challenged group C, challenged plus cinnamaldehyde therapy group D (CnEO @ 1:8000 dilutions through drinking water from 16 to 30 dpi), and challenged plus antibiotic therapy group E (chloramphenicol @ 1 gm/5lit through drinking water from 16 to 30 dpi). Hens from all challenged groups were challenged with Salmonella Gallinarum (VTCCBAA588) @ 1 × 10 CFU/ml orally. Various parameters such as clinical signs, mortality, egg production and egg weight, colony-forming unit (CFU) count of cecal content, eggshell surface, and egg yolk were evaluated all through 60 days of an experimental trial. Results indicated that, in the case of the cinnamaldehyde therapeutic group, there was a significant improvement in egg production, mild clinical signs, lower feed conversion ratio (FCR), and a significantly lower bacterial count in ceca and on the eggshell surface compared to the control challenge group. Thus, CnEO @ 1:8000 dilutions through drinking water can be a potential antimicrobial for controlling fowl typhoid.
Topics: Animals; Female; Oils, Volatile; Typhoid Fever; Chickens; Drinking Water; Poultry Diseases; Salmonella Infections, Animal; Ovum; Anti-Infective Agents
PubMed: 36944831
DOI: 10.1007/s11250-023-03543-1 -
Food Microbiology Jun 2023Non-Typhoidal Salmonella (NTS) continues to be a leading cause of foodborne illness worldwide. Food manufacturers implement hurdle technology by combining more than one...
Non-Typhoidal Salmonella (NTS) continues to be a leading cause of foodborne illness worldwide. Food manufacturers implement hurdle technology by combining more than one approach to control food safety and quality, including preservatives such as organic acids, refrigeration, and heating. We assessed the variation in survival in stresses of genotypically diverse isolates of Salmonella enterica to identify genotypes with potential elevated risk to sub-optimal processing or cooking. Sub-lethal heat treatment, survival in desiccated conditions and growth in the presence of NaCl or organic acids were investigated. S. Gallinarum strain 287/91 was most sensitive to all stress conditions. While none of the strains replicated in a food matrix at 4 °C, S. Infantis strain S1326/28 retained the greatest viability, and six strains exhibited a significantly reduced viability. A S. Kedougou strain exhibited the greatest resistance to incubation at 60 °C in a food matrix that was significantly greater than S. Typhimurium U288, S Heidelberg, S. Kentucky, S. Schwarzengrund and S. Gallinarum strains. Two isolates of monophasic S. Typhimurium, S04698-09 and B54Col9 exhibited the greatest tolerance to desiccation that was significantly more than for the S. Kentucky and S. Typhimurium U288 strains. In general, the presence of 12 mM acetic acid or 14 mM citric acid resulted in a similar pattern of decreased growth in broth, but this was not observed for S. Enteritidis, and S. Typhimurium strains ST4/74 and U288 S01960-05. Acetic acid had a moderately greater effect on growth despite the lower concentration tested. A similar pattern of decreased growth was observed in the presence of 6% NaCl, with the notable exception that S. Typhimurium strain U288 S01960-05 exhibited enhanced growth in elevated NaCl concentrations.
Topics: Salmonella enterica; Sodium Chloride; Food Chain; Serogroup; Salmonella; Acetic Acid; Acids
PubMed: 36906307
DOI: 10.1016/j.fm.2023.104237