Search Results (322)

Migratory birds have been implicated in the spread of diverse emerging infectious pathogens, including West Nile virus, Usutu virus, Avian influenza viruses, Salmonella, Campylobacter, antimicrobial-resistant (AMR) bacteria, and antibiotic resistance genes (ARGs). Beyond their roles as vectors and reservoirs, migratory birds are also susceptible hosts whose own health may be compromised by these infections, reflecting their dual position in the ecology of pathogens. As facilitators of pathogen transmission during their long-distance migrations, often spanning thousands of kilometres and connecting ecosystems across continents, these birds can easily cross-national borders and circumvent traditional biosecurity measures, thereby acting as primary or secondary vectors in the transmission of cross-species diseases among wildlife, livestock, and humans. Africa occupies a pivotal position in global migratory bird networks, yet comprehensive data on pathogen carriage remain limited. Gaps in knowledge of pathogen diversity constrain current surveillance systems, resulting in insufficient genomic monitoring of pathogen evolution and a weak integration of avian ecology with veterinary and human health. These limitations hinder early detection of novel pathogens and reduce the continent’s preparedness to manage outbreaks. Therefore, this review provides a holistic assessment of these challenges by consolidating existing knowledge concerning the pathogens transmitted by migratory birds in Africa, while recognizing the adverse effect of pathogens, which potentiates population decline, extinction, and ecological imbalance. It further advocates for the adoption of a comprehensive One Health-omics approach that not only strengthens surveillance and technological capacity but also prioritizes the protection of avian health as an integral component of ecosystem and public health. Full article

Blood culture remains the gold standard for identifying bloodstream infections caused by bacteria and fungi. Isolation of the culprit microorganism onto agar plates also facilitates antimicrobial susceptibility testing. The purpose of this study was to determine the contamination rates, pathogen profile, and antimicrobial resistance in a secondary healthcare setting in a two-year timeframe. In this study, data regarding blood cultures of the years 2023 and 2024 were retrospectively analyzed to address the above questions. Blood cultures were incubated for seven days before being discarded as negative. The percentage of positive blood cultures for both years was 14.3%. Most positive cultures contained Gram-positive cocci, with a prevalence of coagulase-negative Staphylococci. In descending order, 72.72% were coagulase-negative Staphylococci, 15.15% were Staphylococcus aureus, and 12.12% were Streptococci. One strain of S. aureus was methicillin-resistant (MRSA), and one strain of Enterococcus faecium was vancomycin-resistant (VRE). Of the Gram-negative rods, 78.3% were Enterobacterales. Of these, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis were the top pathogens. The remainder comprised eight strains of Pseudomonas aeruginosa, four strains of Acinetobacter baumannii (one pandrug-resistant), three strains of Stenotrophomonas maltophilia, one strain of Sphingomonas paucimobilis, and one strain of Campylobacter jejuni. The isolated fungi comprised Candida parapsilosis, Candida glabrata, and Candida tropicalis. Of the isolated Escherichia coli strains, 39.5% were resistant to ciprofloxacin regardless of origin (outpatient or hospitalized patients). Outpatient samples were taken in a Hemodialysis Unit that collaborates with our laboratory, obtained from patients with fever or other signs of infection. Distinguishing true bacteremia from contamination remains challenging. The contamination rate in our study was quite high at 5.3%. Since there is no dedicated phlebotomy team in our healthcare setting, in light of our results, educational courses have been conducted to demonstrate the best practices for sample collection. Full article

Objectives: This observational and cross-sectional study investigated differential associations between entero-invasive and non-entero-invasive enteric pathogens and HIV infection, considering socioeconomic, clinical and immunological aspects. In a Ghanaian population with a high prevalence of enteric pathogens, stool samples from people living with HIV (PLWH) were screened for Salmonella spp., Shigella spp./EIEC (enteroinvasive Escherichia coli), and Campylobacter jejuni as entero-invasive bacteria, for enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), and enteroaggregative E. coli (EAEC) as non-entero-invasive bacteria. Arcobacter butzleri, with uncertain enteropathogenicity, was also included. Methods: Stool samples from PLWH (with and without antiretroviral therapy) and HIV-negative controls were analyzed by real-time PCR for the presence and quantity of the selected enteropathogens. Results were correlated with socioeconomic, clinical, and immunological parameters. Results: The presence of Shigella spp. /EIEC in stool was both qualitatively and quantitatively associated with reduced CD4+ T lymphocyte counts and was qualitatively associated with clinically apparent diarrhea. EAEC showed a weak positive association with HIV infection, supported by a negative correlation between EAEC DNA quantity and CD4+ T lymphocyte counts. EPEC colonization was associated with HIV negativity, higher CD4+ T lymphocyte counts, and lower socioeconomic status. Abundance of Salmonella enterica was associated with clinically apparent diarrhea. Conclusions: This explorative, hypothesis-forming study suggests species- or pathovar-specific associations between enteric bacterial pathogens and HIV-related immunosuppression. Observed relationships with clinically apparent diarrhea largely align with findings from sub-Saharan African children, except for a more pronounced association between diarrhea and Salmonella in this cohort. Full article

Interactions between Campylobacter jejuni and host immune cells have been studied using various single-cell line models, such as macrophages and intestinal epithelial cells; however, these single-cell approaches do not fully capture the complexity of the host response. Investigating the interactions between these cell types offers a more comprehensive model for understanding Campylobacter–host dynamics. Therefore, this study aimed to investigate these interactions, specifically between intestinal epithelial cells and macrophages, using an in vitro model of C. jejuni infection. We examined whether soluble factors secreted from C. jejuni-infected HT-29 cells (human colorectal adenocarcinoma cells that express characteristics of mature intestinal cells) at 10 and 50 multiplicities of infection (MOI) influence RAW 264.7 macrophage activity, including nitric oxide (NO) production, migration, phagocytosis, bacterial killing, and the expression of cytokines (IL-6, IL-1β, TNF-α) and the chemokine CCL2. C. jejuni infection of HT-29 cells at 10 MOI induced significant IFN-γ production, a key macrophage activator. The treatment of macrophages with supernatants from HT-29 cells infected with C. jejuni significantly increased NO production, enhanced migration and phagocytic activity, and increased IL-6, TNF-α and CCL2 gene expression. However, no significant killing of phagocytosed C. jejuni was observed. On the other hand, supernatants from HT-29 cells infected with 50 MOI of C. jejuni suppressed NO production and macrophage phagocytosis, which may explain individual variations in the immune system’s ability to contain infection, potentially influenced by the infectious dose. These findings support the notion that Campylobacter can evade macrophage killing even under activated conditions. Further studies are needed to elucidate the molecular mechanisms by which Campylobacter survives within activated macrophages. Full article

Accurate and timely identification of enteric pathogens is crucial for guiding treatment in hospitalized patients with acute diarrhea. Conventional stool testing often lacks sensitivity, whereas multiplex PCR diagnostics offer rapid, comprehensive pathogen detection. This retrospective multicenter study included 267 adult inpatients with acute diarrhea from two hospitals. Patients underwent either traditional stool diagnostics (n = 146) or multiplex PCR testing combined with stool culture (n = 121). Clinical data, diagnostic yields, antibiotic use, and clinical outcomes were analyzed. The multiplex PCR group demonstrated a significantly higher diagnostic yield than traditional testing (77.7% vs. 41.1%, p < 0.001), detecting more mixed infections (34.7%) and a broader range of pathogens, including Campylobacter, viruses, and parasites. PCR positivity correlated independently with bloody diarrhea (OR 16.5; 95% CI: 1.81–150.26) and dehydration (OR 7.05; 95% CI: 1.40–35.45). PCR testing reduced inappropriate antibiotic use (OR 0.30; p < 0.001), shortened antibiotic duration post-result (median 5 vs. 7 days; p < 0.0001), and increased antibiotic adjustments (42.1% vs. 27.4%; p = 0.011) and discontinuation (12.4% vs. 3.7%; p = 0.033). The PCR group had more ICU admissions (20.7% vs. 7.1%, p = 0.001) and longer hospital stays (median 10 vs. 6 days, p < 0.0001), reflecting more severe illness. Liver cirrhosis, comorbidity burden, and systemic inflammation predicted worse outcomes. Multiplex PCR enhances pathogen detection and promotes antibiotic stewardship in hospitalized patients with diarrhea. Rapid results support earlier, targeted clinical decisions, particularly in patients with complex comorbidities or severe presentations. Full article

Bacteriophages, or phages, are viruses that infect and kill specific bacteria, offering a promising alternative to antibiotics in livestock production. With growing concerns over antibiotic resistance, phages have gained renewed interest due to their ability to target harmful pathogens without disturbing beneficial gut microbiota. This review explores the application of dietary phage supplementation in monogastric animals, particularly pigs and poultry. In pigs, phage use has demonstrated beneficial effects such as improved growth performance, enhanced gut health, and reduced infections from Salmonella and E. coli. Various delivery methods, including feed and water supplementation, have been studied, with microencapsulation showing promising results for stability and effectiveness. Similarly, in poultry, phages have been successfully used to control pathogens like Salmonella, Campylobacter, and avian pathogenic E. coli, improving gut health, immunity, and overall performance. Several commercial phage products are already in use, demonstrating both safety and efficacy. Despite these advantages, challenges such as a narrow host range, bacterial resistance, and regulatory limitations remain. Therefore, further research is necessary to understand phage–host interactions, optimize delivery strategies, and evaluate long-term effects under normal and disease-free conditions. This review highlights the potential of bacteriophages as safe, targeted, and sustainable alternatives to antibiotics in monogastric animal production, contributing to improved animal health and reduced antibiotic use. Full article

Cholera remains a major public health challenge, and co-infections can complicate clinical outcomes. In a cross-sectional study, we investigated the prevalence and patterns of enteric co-infections during Zambia’s 2023–2024 cholera outbreak and evaluated their implications for disease severity. 240 suspected cholera patients were enrolled from five healthcare facilities in Lusaka. Stools were tested for 11 enteric pathogens using the Bosphore^® Gastroenteritis Panel Kit v2 on the QuantStudio 5 qPCR, with Vibrio cholerae confirmed by real-time PCR (quantitative PCR). Co-infections were highly prevalent, affecting 79.2% of participants. Campylobacter was the most frequently detected pathogen (70.0%), followed by Norovirus GI/GII (20.0%). Persons living with HIV were significantly more likely to present with co-infections than their counterparts (adjusted PR 1.27, 95% CI: 1.07–1.51; p = 0.008). Participants with confirmed V. cholerae + coinfections (N = 62) were less likely to developed moderate to severe disease compared to those with mono-infections (adjusted PR 0.59, 95% CI: 0.38–0.90; p = 0.014). These findings highlight the high prevalence and complexity of co-infections during cholera outbreaks, potentially contributing to antimicrobial resistance. They also highlight the need for targeted clinical management, particularly among persons living with HIV. Full article

Spotty liver disease (SLD), primarily caused by Campylobacter hepaticus and (less frequently) by Campylobacter bilis, significantly impacts commercial layer hens by causing liver lesions, reducing egg production, and increasing mortality, meaning it can result in serious economic losses for farmers. This study explored the relationship between infection, liver dysfunction, and reproduction, aiming to identify host genetic markers for tracking SLD progression. Hens were orally inoculated with the C. hepaticus strain NSW44L and monitored over a seven-day period. Pathogen colonisation was quantified using qPCR across the liver, bile, caeca, spleen, and ovarian follicles, while liver lesions were scored and hepatic transcriptomes analysed using RNA-seq. C. hepaticus was detected in the liver, caeca, and spleen from one day post-inoculation (dpi) (1.44–1.68 log₁₀ CFU/mL), appeared in bile by the third dpi (3.64 log₁₀ CFU/mL), and reached the follicles by the fourth dpi (3.25 log₁₀ CFU/mL). The highest bacterial loads were found in bile on days six and seven (up to 7.18 CFU/mL). Liver lesions were first observed on the fourth dpi, reaching their peak at the sixth and seventh dpi. Gene expression analysis in liver tissue revealed a notable downregulation of yolk-precursor and metabolic genes, such as prolactin receptor (PRLR), 7-dehydrocholesterol reductase (DHCR7), and malic enzyme 1 (ME1). In contrast, from days three to seven post-infection, there was significant upregulation of avidin (AVD), a biotin-binding protein, and versican (VCAN), which is linked to tissue remodelling and inflammation. These findings correlate with the disease’s progression from initial liver infection to widespread bacterial presence, suggesting value as host biomarkers for effective SLD monitoring and the development of targeted therapies. Full article

The consumption of raw milk has been demonstrated to carry a potential risk of transmission of Campylobacter spp., with Campylobacter jejuni (C. jejuni) and Campylobacter coli (C. coli) being the major causes for foodborne gastroenteritis cases. The present study assessed the prevalence and species distribution of Campylobacter spp. in 633 raw milk samples collected over a one-year climatic cycle from small, medium, and large producers in Pichincha and Manabí, Ecuador. Samples were augmented and analyzed by qPCR for Campylobacter spp., while species identification was performed by duplex PCR and confirmed by 16S rDNA sequencing. The average prevalence of Campylobacter spp. was 49.9% (316/633), with a higher detection rate in Manabí (57.6%, 182/316) compared to Pichincha (42.4%, 134/316). C. coli was the most prevalent species, accounting for 46.2% (146/316) of the cases, followed by C. jejuni at 23.1% (73/316), co-contaminations at 13.3% (42/316), and non-identified Campylobacter at 44.0% (139/316). Phylogenetic analysis was employed to confirm species identity, thereby confirming the presence of Campylobacter fetus and Campylobacter lari. The increased diversity and frequency of isolates in Manabí, particularly during periods of elevated temperature, imply that coastal environmental conditions and production practices promote the persistence of bacteria. The findings of this study indicate a high prevalence of Campylobacter in Ecuadorian raw milk, posing a significant health risk to the population and underscoring the need for enhanced hygiene practices and continuous monitoring to mitigate public health risks. Full article

Background/Objectives: Gastric cancer is known to occur through a multistep process from gastric precancerous lesions, such as atrophic gastritis, intestinal metaplasia, and gastric dysplasia. Gastric precancerous lesions may have different risk factors for each stage, and it can be prevented by an anti-inflammatory diet. In this study, we examined the association between the dietary inflammatory index (DII) and the risk of gastric precancerous lesions among adults in a rural area. Moreover, we analyzed the interaction between the DII and H. pylori infection in relation to the risk of gastric precancerous lesion. Methods: Among 711 participants who had a gastroscopy in a community cohort study, 564 subjects were included in this analysis and were divided into three groups (233 in normal, 128 in atrophic gastritis, and 203 in intestinal metaplasia). Atrophic gastritis and intestinal metaplasia were diagnosed by endoscopy and histopathology in accordance with the Updated Sydney System. DII was derived from a food-frequency questionnaire and categorized into tertiles. H. pylori infection was determined by the Campylobacter-like organism test. Results: H. pylori infection was significantly associated with the increased risk of intestinal metaplasia (OR = 2.75, 95% CI = 1.76–4.27), but not with atrophic gastritis. The inflammation diet itself was not associated with both the risk of atrophic gastritis (OR = 0.93, 95% CI = 0.53–1.64) and intestinal metaplasia (OR = 1.32, 95% CI = 0.78–2.24). However, the risk of intestinal metaplasia was more increased in the inflammatory diet group with H. pylori infection (OR = 3.35, 95% CI = 1.54–7.30) compared to the anti-inflammatory diet group without H. pylori infection. Conclusions: This study found that H. pylori infection increased the risk of intestinal metaplasia, and this risk was further enhanced by a pro-inflammatory diet, suggesting that both diet and infection management are important for prevention of gastric precancerous lesions. Full article

Phytotherapy is a growing field of modern medicine, offering natural alternatives with multidirectional pharmacological effects. Among plant-derived bioactive compounds, isoquinoline alkaloids exhibit antioxidant, anti-inflammatory, and antimicrobial properties. Our in vitro model of campylobacteriosis confirmed that berberine reduces pathological changes in colonocytes not only through its direct antibacterial (minimum inhibitory concentration for pure berberine against Campylobacter jejuni was 64 μg/mL) and anti-biofilm (fourfold reduction in C. jejuni biomass) effects, but also through its protective effect on the morphostructure and secretory profile of host cells exposed to bacterial components. Furthermore, berberine stabilized intercellular junction proteins, modulated bile acid and arachidonic acid metabolism, and supported host-protective signaling pathways. These findings indicate that berberine acts through a dual mechanism—directly reducing bacterial virulence while enhancing intestinal barrier integrity and metabolic homeostasis. In summary, berberine appears to be a multifunctional phytochemical in the development of new strategies for the prevention and treatment of C. jejuni-induced gastrointestinal infections and epithelial barrier dysfunctions. The protective effect we have demonstrated may contribute to alleviating the phenomenon of “leaky gut,” commonly associated with campylobacteriosis. Full article

Zoonotic bacteria, namely Campylobacter spp., Escherichia coli, Salmonella spp. and Staphylococcus aureus, are commonly implicated in human infections and can be transmitted from animals to humans through direct contact, the environment or the food chain. The emergence of antimicrobial resistance in these zoonotic bacteria, namely extended spectrum β-lactamases (ESBLs)-producing strains of E. coli and methicillin-resistant S. aureus (MRSA), has become a public health concern worldwide. This study aimed to determine the prevalence of fecal carriage of Campylobacter spp., Salmonella spp. and ESBL-producing strains of E. coli, as well as nasal carriage of MRSA, and to identify risk factors associated with the presence of these zoonotic bacteria in small ruminants from Portugal’s Central Region. A total of 732 animals, of which 432 sheep and 300 goats from 122 farms were sampled. Zoonotic enteric bacteria were isolated from individual fecal samples, while MRSA were isolated from pooled nasal swabs collected from each farm. Bacteria were isolated according to standard microbiological methods. The overall prevalence of Campylobacter spp. and Salmonella spp. at the animal level was 15.6% and 8.3%, respectively, with significantly higher prevalence in sheep (19.0% and 12.7%) compared to goat (10.7% and 2.0%). Presumptive ESBL-producing strains of E. coli was isolated from 5.2% of the animals. Presumptive MRSA was isolated from 5.7% of the farms. A cluster analysis was performed to identify farm clusters with similar characteristics based on the isolation of Campylobacter spp., Salmonella spp., presumptive ESBL-producing E. coli, and presumptive MRSA. Farms were grouped into three clusters: “Resistant”, “Campylobacter” and “Salmonella”. The likelihood of farms belonging to “Campylobacter” and “Salmonella” clusters in comparison to “Resistant” cluster was associated with animal species, farm location, and farmer’ practices regarding antibiotic use. This study reinforces the role of small ruminants as asymptomatic reservoirs of Campylobacter spp., Salmonella spp., E. coli and S. aureus and confirms, for the first time, their role as carriers of presumptive antibiotic-resistant zoonotic bacteria in Portugal’s Central Region. Full article

Campylobacter spp. remain among the most common pathogens causing acute diarrhea worldwide. Campylobacter jejuni and Campylobacter coli are the main species that cause gastroenteritis. Campylobacteriosis is a food-borne disease, although this Gram-negative bacterium may be transmitted via water-borne outbreaks as well as direct contact with animals, emphasizing its zoonotic potential. Campylobacterisosis does not usually require hospitalization. Antimicrobials are warranted only for patients with severe disease, as well as patients who are at risk for severe disease, such as the elderly, pregnant women or immunocompromised patients. Nonetheless, the irrational use of antibiotics in human and veterinary medicine enhances antimicrobial resistance (AMR). Resistance of Campylobacter spp. to fluoroquinolones, macrolides and tetracyclines is a significant concern to the scientific community. Point mutations, horizontal gene transfer and efflux pumps are the main mechanisms for the development and transmission of AMR in Campylobacter spp. Emerging evidence suggests that climate change may indirectly contribute to the spread of AMR in Campylobacter, particularly through its influence on bacterial ecology, transmission pathways and antibiotic use patterns. Higher temperatures and extreme weather events accelerate bacterial growth, amplify the transfer of AMR genes and magnify disease transmission, including drug-resistant infections. Horizontal gene transfer, especially in the context of biofilm formation, may further perplex the situation. Excessive farming and overuse of antibiotics as growth promoters in animals may also contribute to increased AMR rates. Climate change and AMR are interconnected and pose a significant threat to global public health. Multidisciplinary strategies mitigating both phenomena are crucial in order to contain the spread of Campylobacter-related AMR. The aim of this review is to describe the molecular mechanisms that result in AMR of Campylobacter spp. and underscore the association between climate change and Campylobacteriosis. Novel methods to mitigate Campylobacter-related AMR will also be discussed. Full article

Campylobacter hepaticus is the etiological agent of Spotty Liver Disease (SLD), a newly emerging bacterial disease of laying hens resulting in significant mortality and production losses primarily in free-range systems. Although its economic impact continues to grow, the molecular basis of C. hepaticus pathogenesis remains poorly understood. In this study, we conducted transcriptomic profiling of C. hepaticus in three host-relevant conditions, exposure to chicken bile, infection of a chicken liver hepatocellular carcinoma (LMH) cell line, and isolation from liver lesions of naturally infected chickens. Through RNA-seq analysis, we found unique gene expression signatures in each environment. In the bile, C. hepaticus exhibited differential expression of 412 genes, with upregulation of genes related to motility, cell envelope remodeling, glycosylation, nitrate respiration, and multidrug efflux systems, indicating a stress-adaptive, metabolically active lifestyle. In LMH, on the other hand, 125 genes were differentially expressed, primarily reflecting downregulation of motility, oxidative stress response, chaperones, and core metabolic processes, suggesting that these cells adopt a less active, intracellular dormant lifestyle. Transcriptomic analysis of C. hepaticus isolated from the liver identified 26 differentially expressed genes, featuring selective upregulation of genes associated with nitrate respiration, sulfur metabolism, and pyridoxal 5’ phosphate homeostasis, alongside downregulation of the major outer membrane porin (momp), stress response chaperones (dnaK, groL), and genes involved in oxidative stress defense and energy production. Furthermore, the immune evasion-related gene cmeA and a glycosyltransferase gene were found to be highly upregulated. This study presents the first in-depth transcriptomic exploration of C. hepaticus in multiple host relevant niches. Our findings reveal niche-specific gene expression profiles and highlight metabolic and structural adaptations that enable C. hepaticus to survive during bile exposure, persist within host cells, and contribute to liver pathology. These insights provide a basis for identifying novel virulence determinants and may inform the development of targeted interventions, including vaccines or antimicrobial therapy, to control SLD in commercial poultry operations. Full article

Campylobacter is a leading cause of human gastroenteritis, with poultry serving as the primary reservoir host. Effective preharvest control strategies are crucial for preventing or reducing Campylobacter contamination on meat surfaces. As concerns grow regarding the use of antimicrobials in animal agriculture, the importance of non-antimicrobial preharvest strategies in poultry production has become increasingly significant. This comprehensive review focuses on the biology of Campylobacter, its impact on public health, and current and emerging preharvest strategies, with a special emphasis on vaccination. Preharvest strategies are broadly classified into biosecurity measures, gut microbiota modifications using prebiotics, probiotics, postbiotics, feed additives, and vaccination. While some vaccines have proven to be effective in research settings, no commercial vaccines are currently available. Because no single strategy can effectively combat Campylobacter, integrating multiple approaches, such as improved biosecurity measures, immunization, and dietary modifications, may provide a solution for reducing Campylobacter loads in poultry. Embracing a “One Health” approach, gaining a deeper understanding of Campylobacter pathophysiology, advancing vaccine technology, and implementing holistic farm management practices will be essential for the sustainable control of Campylobacter and for reducing the risk of human campylobacteriosis. Full article