Search Results (119)

Background: Avian pathogenic Escherichia coli (APEC) is a leading cause of colibacillosis in poultry. Piper betle L. is a medicinal plant rich in bioactive compounds including hydroxychavicol that possess potent antibacterial activity. This study aimed to investigate the efficacy of a P. betle L. leaf nanoemulsion (NEPE) and hydroxychavicol against multidrug-resistant APEC isolates. Methods: In vitro and in silico analysis of NEPE and hydroxychavicol against APEC were determined. Results: The nanoemulsion exhibited potent antibacterial activity, with MIC and MBC values of 0.06–0.25% v/v and 0.125–0.25% v/v, respectively. The MIC and MBC values of hydroxychavicol against isolates ranged from 0.25 to 1.0 mg/mL. A time–kill assays revealed rapid bactericidal effects of both compounds, achieving a ≥3-log reduction within 4 h at 4 × MIC. Scanning electron microscopy demonstrated that APEC cells treated with hydroxychavicol exhibited filamentous cells with incomplete septa. Molecular docking and dynamics simulations of hydroxychavicol against APEC cell division proteins were investigated. According to the binding energy, hydroxychavicol exhibited the highest affinity with ZapE, FtsW, FtsX, FtsZ, and FtsA, respectively. However, the FtsA protein showed the least protein conformational change throughout the 5000 ns simulation, reflecting a highly stable conformation. Conclusions: These confirm the potential stability of protein and ligand, as supported by molecular dynamics simulation. The results suggested the potential of NEPE and hydroxychavicol, which may have promising antibacterial potential that can be used to inhibit APEC growth. Full article

The genotoxin colibactin, a complex secondary metabolite, targets eukaryotic cell cycle machinery and contributes to neonatal sepsis and meningitis. Avian pathogenic Escherichia coli (APEC) XM, which produces this genotoxin, is an agent of poultry diseases with zoonotic potential. In this study, we confirmed that clbF was necessary for the APEC XM strain to produce colibactin, but it did not affect the growth, adhesion, or invasion of cells. Deletion of clbF substantially diminished both virulence and systemic dissemination, but it also changed the gene expression of the antiserum survival factor, adherence and invasion, iron acquisition genes, and the secretion system. In conclusion, clbF is necessary for the synthesis of the genotoxin colibactin and affects the development of APEC meningitis in mice. Full article

Avian pathogenic Escherichia coli (APEC) is highly infective in poultry, causing significant economic losses to the poultry industry. As an extraintestinal pathogenic strain, adherence is a critical step in the infection. The functions of several adhesins, including type I, P, and Curli fimbriae, have been extensively studied. However, the roles of other adhesins, like Sfm, remain largely unexplored. Sfm is widely present in E. coli. Although the Sfm cluster is an ortholog of the fim gene cluster of Salmonella type I fimbriae, the biological function of Sfm in APEC has not yet been elucidated. To investigate whether Sfm in APEC CE129 plays a role in virulence, in this study, we constructed recombinant strains by expressing Sfm in the fimbriae-deficient strain SE5000. Additionally, a CE129 sfmA mutant strain was constructed. The resulting changes in adherence, biofilm formation, resistance to macrophage phagocytosis, and resistance to serum bactericidal ability were observed. The adherence ability of CE129ΔsfmA was reduced by 41%. HD-11 cells demonstrated a 30% increase in the phagocytosis of CE129ΔsfmA, and a 50% reduction in SE5000 (pBR322-sfm). The sfm deletion mutant showed a 23.9% reduction in the resistance to serum bactericidal ability, while SE5000 (pBR322-sfm) displayed a 32% increase. SE5000 (pBR322-sfm) exhibited a 34% increase in biofilm formation, and CE129ΔsfmA demonstrated a 21% decrease. Real-time PCR was employed to examine the impact of Sfm deletion on the transcription level of key virulence factors (fimA, fliC, papC, tsh, ompA, and iss). The results indicated that Sfm in CE129 is closely associated with bacterial adherence and survivability, contributing to biofilm formation and influencing the expression of key virulence factors. This study yields initial insight into the functional roles of Sfm in APEC and provides a foundation for the effective control of E. coli in the poultry industry. Full article

Avian pathogenic Escherichia coli (APEC) poses a global threat to poultry health and public safety due to its high lethality, limited treatment options, and potential for zoonotic transmission via the food chain. However, long-term genomic surveillance remains limited, especially in countries like China where poultry farming is highly intensive. This study aimed to characterize the population structure, virulence traits, and antimicrobial resistance of 81 APEC isolates from diseased chickens collected over 16 years from Shandong and neighboring provinces in eastern China. The isolates were grouped into seven Clermont phylogroups, with A and B1 being dominant. MLST revealed 27 STs, and serotyping identified 29 O and 16 H antigens, showing high genetic diversity. The minor phylogroups (B2, C, D, E, G) encoded more virulence genes and had higher virulence-plasmid ColV carriage, with enrichment for iron-uptake, protectins, and extraintestinal toxins. In contrast, the dominant phylogroups A and B1 primarily carried adhesin and enterotoxin genes. Antimicrobial resistance was widespread: 76.5% of isolates were multidrug-resistant. The minor phylogroups exhibited higher tetracycline resistance (mediated by tet(A)), whereas the major phylogroups showed increased resistance to third- and fourth-generation cephalosporins (due to bla_CTX-M-type ESBL genes). These findings offer crucial data for APEC prevention and control, safeguarding the poultry industry and public health. Full article

A novel bivalent oral vaccine candidate against H5N1 and H9N2 avian influenza virus (AIV) was developed using Lactobacillus surface display technology without genetic modification. The hemagglutinin subunit 1 (HA1) antigens from both subtypes were fused to the surface layer-binding domain of Lactobacillus crispatus K313, expressed in Escherichia coli, and purified. Wild-type Lactobacillus johnsonii H31, isolated from chicken intestine, served as a delivery vehicle by adsorbing and stably displaying the HA1 proteins on its surface. This approach eliminates the need for bacterial engineering while utilizing lactobacilli’s natural capacity to protect surface-displayed antigens, as evidenced by HA1’s protease resistance. Mouse immunization studies demonstrated induction of strong systemic IgG and mucosal IgA responses against both H5N1 and H9N2 HA1. The system offers several advantages, including safety through non-GMO probiotics, potential for multivalent vaccine expansion, and intrinsic antigen protection by lactobacilli. These findings suggest this platform could enable development of cost-effective, multivalent AIV vaccines. Full article

Escherichia coli (E. coli) remains a major concern in poultry production due to its ability to incite foodborne illness and public health crisis, zoonotic potential, and the increasing prevalence of antibiotic-resistant strains. The contamination of poultry products with pathogenic E. coli, including avian pathogenic E. coli (APEC) and Shiga toxin-producing E. coli (STEC), presents risks at multiple stages of the poultry production cycle. The stages affected by E. coli range from, but are not limited to, the hatcheries to grow-out operations, slaughterhouses, and retail markets. While traditional detection methods such as culture-based assays and polymerase chain reaction (PCR) are well-established for E. coli detection in the food supply chain, their time, cost, and high infrastructure demands limit their suitability for rapid and field-based surveillance—hindering the ability for effective cessation and handling of outbreaks. Biosensors have emerged as powerful diagnostic tools that offer rapid, sensitive, and cost-effective alternatives for E. coli detection across various stages of poultry development and processing where detection is needed. This review examines current biosensor technologies designed to detect bacterial biomarkers, toxins, antibiotic resistance genes, and host immune response indicators for E. coli. Emphasis is placed on field-deployable and point-of-care (POC) platforms capable of integrating into poultry production environments. In addition to enhancing early pathogen detection, biosensors support antimicrobial resistance monitoring, facilitate integration into Hazard Analysis Critical Control Points (HACCP) systems, and align with the One Health framework by improving both animal and public health outcomes. Their strategic implementation in slaughterhouse quality control and marketplace testing can significantly reduce contamination risk and strengthen traceability in the poultry value chain. As biosensor technology continues to evolve, its application in E. coli surveillance is poised to play a transformative role in sustainable poultry production and global food safety. Full article

Avian pathogenic Escherichia coli (APEC) causes avian colibacillosis, leading to significant economic losses and concerns for food safety in the poultry industry. This study focused on examining the virulence gene profile, antibiotic resistance prevalence, and resistance patterns of APEC isolates. A total of 250 bacterial strains were collected from birds affected by colibacillosis. Serogrouping revealed diverse serotypes, with O2 being the most common (16%), followed by O1, O8, and O76. All isolates tested positive for at minimum one virulence gene, with 7.2% carrying all five targeted genes, particularly in serogroups O1, O8, O45, and O88. The most detected gene was iss, present in 79.6% of isolates, followed by tsh, iucC, sitA, and papC. The antibiotic resistance analysis showed that all isolates exhibited multidrug resistance, although they remained susceptible to gentamicin, amikacin, ciprofloxacin, and chloramphenicol. Moreover, specific antibiotic resistance genes were known in the isolates, with tetA detected in 54.8%, tetB in 51.7%, sul1 in 50%, and aadA1 in 29.2%. These findings highlight the widespread antibiotic resistance in chicken carcasses, which poses a hazard to human health in terms of transfer of resistance to humans, reduced effectiveness of antibiotics and impaired ability to contain infectious diseases. Therefore, it is crucial to implement strict monitoring programs to regulate antibiotic usage in poultry production. Full article

Antimicrobial resistance (AMR) is a major global concern in both human and veterinary medicine. Among antimicrobial resistance (AMR) bacteria, Extended-Spectrum Beta-Lactamases (ESBLs) pose a serious health risk because infections can be difficult to treat. These Gram-negative bacteria can be frequently found in poultry and in Italy, where such protein production is established. ESBL-producing Escherichia coli, Salmonella and Klebsiella in chicken and turkey may pose a significant public health risk due to potential transmission between poultry and humans. This review aims to assess the prevalence of ESBL-producing E. coli, Salmonella and Klebsiella phenotypically and genotypically in Italian poultry, identifying the most common genes, detection methods and potential information gaps. An initial pool of 1462 studies found in scientific databases (Web of Sciences, PubMed, etc.) was screened and 29 were identified as eligible for our review. Of these studies, 79.3% investigated both phenotypic and genotypic ESBL expression while ${bla}_{CTX-M}$, ${bla}_{TEM}$ and ${bla}_{SHV}$ were considered as targeted gene families. Large differences in prevalence were reported (0–100%). The ${bla}_{CTX-M-1}$ and ${bla}_{TEM-1}$ genes were the most prevalent in Italian territory. ESBL-producing E. coli, Salmonella and Klebsiella were frequently detected in farms and slaughterhouses, posing a potential threat to humans through contact (direct and indirect) with birds through handling, inhalation of infected dust, drinking contaminated water, ingestion of meat and meat products and the environment. Considering the frequent occurrence of ESBL-producing bacteria in Italian poultry, it is advisable to further improve biosecurity and to introduce more systematic surveillance. Additionally, the focus should be on the wild birds as they are ESBL carriers. Full article

Avian colibacillosis causes significant economic losses and raises concerns for human health due to food safety risks, a problem exacerbated by the increase in antibiotic resistance. This study aimed to develop novel antibacterial strategies using fermented liquid of Sini decoction dregs to address these challenges. We analyzed the transcriptome of the chicken thymus sample GSE69014 in the GEO database to identify immune-related genes, performed molecular docking to assess compound interactions, and experimental validation via Western blot and ELISA to evaluate anti-inflammatory effects. Results revealed 11 core genes, including TLR4, critical for immune responses against the infection, with TLR4 activating key inflammatory pathways. Fermented liquid with probiotics enhanced bioactivity, and natural compounds Dioscin and Celastrol from the fermented liquid inhibited inflammation by targeting the TLR4-MD2 complex. In animal models, fermented liquid outperformed individual compounds, likely due to synergistic effects, significantly reducing inflammatory markers. These findings demonstrate that fermented liquid of Sini decoction dregs offers a promising, sustainable approach to control avian colibacillosis, mitigate antibiotic resistance, and improve poultry health, providing a scientific foundation for its application in farming to reduce economic losses and enhance food safety. Full article

This retrospective study investigated the clinical presentation, diagnostic findings, and treatment outcomes in 419 backyard (pet) chickens admitted to the Service for Avian and Reptiles at the University of Veterinary Medicine Vienna from 1 May 2009 to 30 April 2019. The median age of the chickens was 1.5 years, with 83.8% being female. The majority (80.0%) presented with individual clinical issues, while 20.0% were diagnosed with flock diseases. The most common admission causes included unspecific clinical signs (57.3%), respiratory tract issues (18.4%), and locomotor problems (16.2%). Diagnostic imaging modalities such as ultrasonography, radiography, and CT scans revealed pathologies, including ascites, salpingitis, and skeletal system abnormalities. Parasitological examinations found a high rate of coccidia, Capillaria, and Ascaridia, while microbiological analysis identified Escherichia coli and Pasteurella multocida as common bacterial pathogens. The most prevalent diseases were upper respiratory tract infections (13.8%), egg peritonitis (9.9%), and soft tissue trauma (9.4%). Treatment outcomes showed that 67.5% survived to discharge, while 32.2% died or were euthanized. Surgical interventions were performed in 25.3% of cases, with the most common surgeries being salpingohysterectomy and wound debridement. This study highlights the wide range of health issues faced by pet chickens and emphasizes the importance of accurate diagnosis and targeted treatment in avian veterinary care. It also underscores the role of various diagnostic tools, such as imaging, pathogen detection, and histopathology, in addressing the health challenges of backyard chickens. Full article

Escherichia coli (E. coli) represents a significant etiological agent of colibacillosis in poultry, resulting in considerable economic losses for the global poultry sector. The present study aimed to determine molecular characterization, antibiotic resistance, and biofilm formation of E. coli strains isolated from diseased broilers from four provinces of China. A total of 200 tissue samples were collected from the intestine, liver, crop, heart, and spleen and processed for microbiological examination. Molecular detection of E. coli strains, virulence genes, and serotypes was performed using polymerase chain reaction (PCR). Antibiotic susceptibility testing and biofilm formation were assessed using disk diffusion and 96-well microtiter plate assays. The study retrieved 68% (136/200) of E. coli strains from collected samples. Most of the E. coli strains were resistant to enrofloxacin (56%), followed by cefepime (54%), amoxicillin/clavulanate (52%), streptomycin (50%), ampicillin (48%), clindamycin (47%), kanamycin (41%), polymyxin B (37%), tetracycline (35%), sulfamethoxazole/trimethoprim (33%), ceftazidime (31%), meropenem (4.7%), and florfenicol (2.9%). Similarly, the E. coli strains tested positive for at least one virulence gene and specific serotypes. Among these, O145 was the most prevalent serotype, identified in 22 isolates (16.2%), followed by O8 (12.5%), O102 (11.8%), and O9 (11.0%). The tsh gene (10.2%) was the most prevalent virulence gene. This study found that 47.1% of E. coli strains were biofilm-producing, with 62.5% exhibiting weak biofilm production, 29.7% mild biofilm production, and 7.8% strong biofilm production. Similarly, 24.2% of the E. coli strains were avian pathogenic E. coli strains due to the presence of five or more virulence genes, specifically tsh, ompA, fimC, iss, fyuA, and astA, in a single strain by multiplex PCR. The present study recommends continuous surveillance and effective control measures to reduce the burden of avian pathogenic E. coli-related infections in poultry. Full article

The present study was conducted to assess the efficacy of Laboratory-Isolated Lactocaseibacillus casei NK1 (Lc. NK1) in broilers hypothesizing that, Lc. NK1 supplementation will enhance growth performance, modulate the gut microbiome, and reduce fecal pathogenic Escherichia coli in broilers. The experiment spanned 35 days where 60 one-day-old broiler chicks were randomly assigned to four treatment groups (n = 15); control-group with no treatment (NC), APEC (challenged with E. coli only), CProb (received commercial probiotics), and LNK1 (treated with Lc. NK1). The APEC, CProb, and LNK1 groups were infected with E. coli O78 strain at 11 days of age. Growth performance analysis revealed that the LNK1 group by day 35 gained body weight similar to the CProb group, with both groups significantly outperforming the APEC group (p < 0.001). Both the LNK1 and CProp groups exhibited similar reduction in E. coli while increasing Lactobacillus colorizations in the cloacal swabs from day 21 to 35 of age (p > 0.05). Metagenomic analysis using 16S rRNA sequencing showed that the LNK1 group maintained a diverse and balanced gut microbiota, characterized by increased Firmicutes and reduced Proteobacteria. In contrast, the APEC group exhibited reduced diversity and dominance of Escherichia-Shigella (p < 0.001). These findings suggest Lc. NK1 could be a promising probiotic for enhancing gut health and growth performance in broilers, even under pathogenic challenges, offering a potential alternative to antibiotics in poultry production. Full article

Avian colibacillosis caused by avian pathogenic Escherichia coli (APEC) strains is a bacterial disease responsible for enormous economic losses in the poultry industry, due to high mortality rates in farms, antibiotic therapy costs, and seizures at slaughterhouses. The aim of this study was to characterize the serogroups and molecular features of extended spectrum β-lactamase (ESBL)-producing APEC isolates recovered from 248 liver samples of 215 broilers and 33 turkeys with colibacillosis lesions in northeast Algeria. For this, microbiological tests were carried out, according to the recommended standards: E. coli isolates were recovered using standard microbiological protocols, and identification was carried out by MALDI-TOF MS. Serogrouping was performed using a rapid agglutination slide and the antisera of three O somatic groups (O1, O2, O78). Antimicrobial susceptibility was determined by the disk diffusion method. PCR assays and sequencing were used to detect antimicrobial resistance genes, integrons, phylogrouping, and MLST. Conjugation experiments were also conducted to determine the transferability of the retrieved ESBL-encoding genes. Overall, 211 (85.1%) APEC isolates were collected (one per positive sample), and 164 (77.7%) of them were typable. The O2 and O1 serogroups were the most detected (46.1% in broiler typable isolates and 61.5% in turkey typable isolates). Seventeen APEC isolates were ESBL-producers and harbored the following genes (number of isolates): bla_CTX-M-1 (14), bla_CTX-M-15 (2), and bla_SHV-12 (1). They belonged to phylogroups D (10 isolates), B1 (6 isolates), and B2 (1 isolate). The MLST of 13 ESBL producers revealed seven STs: ST23, ST38, ST48, ST117, ST131, ST1146, and ST5087. The ESBL-encoding genes were transferred by conjugation among 15 ESBL-producing isolates, and transconjugants acquired either the IncK or IncI1 plasmids. Concerted efforts from all poultry actors are needed to establish surveillance monitoring strategies to mitigate the spread of ESBL-producing isolates implicated in avian colibacillosis. Full article

Introduction: Ostrich farming is increasingly recognized for its economic potential but poses significant health challenges due to the risk of pathogen transmission, including multidrug-resistant Escherichia coli. Case study: This study reports a case of a four-month-old female ostrich from western Romania presenting with severe respiratory and digestive infections, progressing to septicemia and death. A post-mortem examination revealed extensive mucus in the trachea, pulmonary congestion, hemorrhagic enteritis, and approximately 1250 g of metal objects in the ventriculus. Pure cultures of E. coli were isolated from the lungs and bone marrow and identified via MALDI-TOF MS. The strain exhibited multidrug resistance to several antibiotics, including enrofloxacin, doxycycline, and amoxicillin, highlighting the critical issue of antimicrobial resistance in veterinary medicine. Discussions: This case underscores the need for enhanced management practices in ostrich farming to mitigate environmental and pathogenic risks, as well as the urgency of developing alternative strategies for controlling resistant bacterial infections in avian species. Conclusions: This case highlights the need for alternative treatments and stricter antimicrobial stewardship to combat multidrug-resistant E. coli in ostriches. Full article

Avian pathogenic Escherichia coli (APEC) causes bloodstream infections mainly by resisting the bactericidal action of host serum. Although various protein and polysaccharide factors involved in serum resistance have been identified, the role of small non-coding RNA (sRNA) in serum resistance has rarely been studied. The sRNA RyhB contributes to serum resistance in APEC, but the regulation mechanism of RyhB to serum resistance-related targets remains unknown. Here, we studied the regulatory mechanism of RyhB on capsule synthesis and how RyhB regulates serum resistance, macrophage phagocytosis resistance, and pathogenicity to natural hosts by regulating capsule synthesis. The results showed that RyhB upregulates capsular synthesis by interacting with the promoter regions of the capsule gene cluster and activating the translation of the capsule. The deletion of ryhB and/or neu reduced the ability of resistance to serum, macrophage phagocytosis, and pathogenicity of APEC in ducks. It can be concluded that RyhB directly upregulates the expression of capsular gene cluster and capsular synthesis and then indirectly promotes resistance to serum and macrophage phagocytosis and pathogenicity to ducks. Full article