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Biology Apr 2024is one of the main causative agents leading to acute hepatopancreatic necrosis disease, the severe bacterial disease that occurs during shrimp aquaculture. Hemocytes...
is one of the main causative agents leading to acute hepatopancreatic necrosis disease, the severe bacterial disease that occurs during shrimp aquaculture. Hemocytes play important roles during infection. Previously, we found that there were few differentially expressed genes (DEGs) between hemocytes from -resistant and -susceptible shrimp before infection. We considered that there should be different immune responses between them after a pathogen infection. Here, the transcriptome data of hemocytes from -resistant and -susceptible shrimp before and after a pathogen infection were compared. The results showed that there were 157 DEGs responsive to infection in -resistant shrimp, while 33 DEGs in -susceptible shrimp. DEGs in -resistant shrimp were mainly related to immune and glycolytic processes, while those in -susceptible shrimp were mainly related to metabolism, with only two DEGs in common. A further analysis of genes involved in glucose metabolism revealed that GLUT2, HK, FBP, and PCK1 were lowly expressed while PC were highly expressed in hemocytes of the -resistant shrimp, indicating that glucose metabolism in shrimp hemocytes was related to a infection. After the knockdown of PC, the expression of genes in Toll and IMD signaling pathways were down-regulated, indicating that glucose metabolism might function through regulating host immunity during infection. The results suggest that the immune responses between -resistant and -susceptible shrimp were apparently different, which probably contribute to their different resistance abilities.
PubMed: 38785782
DOI: 10.3390/biology13050300 -
Journal of Fish Diseases May 2024Diseases caused by pathogens commonly occurring in the aquatic environment or those that are non-host specific are prevalent and threaten the rapid growth of tropical...
Diseases caused by pathogens commonly occurring in the aquatic environment or those that are non-host specific are prevalent and threaten the rapid growth of tropical aquaculture. This study investigates causes of mortality in 12 batches of newly stocked juvenile Lates calcarifer from three different hatcheries. Cytology based on Diff-Quik™-stained tissue and blood smears provides rapid diagnosis of possible causes of mortality, while histopathology and haematology provide a better understanding of how prolonged transport and fish with existing chronic disease are more likely to experience elevated mortality post-stocking. Our findings showed that accumulation of ammonia during prolonged transport causes extensive damage to epithelial barriers in gastrointestinal tracts and depressed immunity due to marked hypoglycaemia, predisposing fish to acute Streptococcosis. Lates calcarifer with chronic bacterial enteritis developed severe hypoglycaemia, had low circulating total plasma protein, and suffered high mortality within 24 hours post-stocking. Hypoglycaemia and low circulating blood proteins disrupt osmoregulation and exacerbate dehydration, which is fatal in fish in sea water. Dying L. calcarifer tested PCR positive for scale drop disease virus (SDDV) at 28 days post-stocking showed a 10-fold elevation of white blood cell counts, severe vasculitis, and obstruction of blood supply to major organs. Destruction of important immune organs such as spleen is a hallmark of SDDV infection that explains high incidences of opportunistic Vibrio harveyi infections in 61% of fish with SDDV. Overall, this study reiterates the importance of stocking disease-free fish and reducing transport stress.
PubMed: 38785265
DOI: 10.1111/jfd.13963 -
Mathematical Biosciences Jul 2024Diverse modelling techniques in cholera epidemiology have been developed and used to (1) study its transmission dynamics, (2) predict and manage cholera outbreaks, and... (Review)
Review
Diverse modelling techniques in cholera epidemiology have been developed and used to (1) study its transmission dynamics, (2) predict and manage cholera outbreaks, and (3) assess the impact of various control and mitigation measures. In this study, we carry out a critical and systematic review of various approaches used for modelling the dynamics of cholera. Also, we discuss the strengths and weaknesses of each modelling approach. A systematic search of articles was conducted in Google Scholar, PubMed, Science Direct, and Taylor & Francis. Eligible studies were those concerned with the dynamics of cholera excluding studies focused on models for cholera transmission in animals, socio-economic factors, and genetic & molecular related studies. A total of 476 peer-reviewed articles met the inclusion criteria, with about 40% (32%) of the studies carried out in Asia (Africa). About 52%, 21%, and 9%, of the studies, were based on compartmental (e.g., SIRB), statistical (time series and regression), and spatial (spatiotemporal clustering) models, respectively, while the rest of the analysed studies used other modelling approaches such as network, machine learning and artificial intelligence, Bayesian, and agent-based approaches. Cholera modelling studies that incorporate vector/housefly transmission of the pathogen are scarce and a small portion of researchers (3.99%) considers the estimation of key epidemiological parameters. Vaccination only platform was utilized as a control measure in more than half (58%) of the studies. Research productivity in cholera epidemiological modelling studies have increased in recent years, but authors used diverse range of models. Future models should consider incorporating vector/housefly transmission of the pathogen and on the estimation of key epidemiological parameters for the transmission of cholera dynamics.
Topics: Cholera; Humans; Epidemiological Models; Disease Outbreaks
PubMed: 38777029
DOI: 10.1016/j.mbs.2024.109210 -
Tropical Medicine & International... Jul 2024Globally, there are estimated to be 2.9 million cholera cases annually. Early detection of cholera outbreaks is crucial for resource allocation for case management and...
Evaluation of a rapid diagnostic test for detection of Vibrio cholerae O1 in the Democratic Republic of the Congo: Preventative intervention for cholera for 7 days (PICHA7 program).
OBJECTIVE
Globally, there are estimated to be 2.9 million cholera cases annually. Early detection of cholera outbreaks is crucial for resource allocation for case management and for targeted interventions to be delivered to stop the spread of cholera. In resource limited settings such as Eastern Democratic Republic of the Congo (DRC), there is often limited laboratory capacity for analysing stool samples for cholera by bacterial culture. Therefore, rapid diagnostic tests (RDTs) for cholera present a promising tool to rapidly test stool samples in a health facility setting for cholera. Our objective is to evaluate the Crystal VC O1 RDT for cholera detection compared with bacterial culture and polymerase chain reaction (PCR) for Vibrio cholerae.
METHODS
From March 2020 to December 2022, stool samples were collected from 644 diarrhoea patients admitted to 94 health facilities in Bukavu in Eastern DRC. Patient stool samples were analysed by Crystal VC O1 RDT for cholera and by bacterial culture and PCR for V. cholerae O1.
RESULTS
Twenty six percent of diarrhoea patients (166/644) had stool samples positive for cholera by RDT, and 24% (152/644) had stool samples positive for V. cholerae O1 by bacterial culture or PCR. The overall specificity and sensitivity of the Crystal VC O1 RDT by direct testing was 94% (95% confidence interval [CI]: 92%-96%) and 90% (95% CI, 84%-94%), respectively, when compared with either a positive result by bacterial culture or PCR.
CONCLUSION
Our findings suggest that the Crystal VC O1 RDT presents a promising tool for cholera surveillance in this cholera endemic setting in sub-Saharan Africa.
Topics: Humans; Cholera; Democratic Republic of the Congo; Vibrio cholerae O1; Male; Feces; Female; Adult; Adolescent; Middle Aged; Young Adult; Sensitivity and Specificity; Child; Diarrhea; Child, Preschool; Polymerase Chain Reaction; Diagnostic Tests, Routine; Infant; Aged; Disease Outbreaks; Rapid Diagnostic Tests
PubMed: 38773948
DOI: 10.1111/tmi.13998 -
Scientific Reports May 2024Climate change and disease threaten shrimp farming. Here, we studied the beneficial properties of a phytogenic formulation, Shrimp Best (SB), in whiteleg shrimp....
Climate change and disease threaten shrimp farming. Here, we studied the beneficial properties of a phytogenic formulation, Shrimp Best (SB), in whiteleg shrimp. Functional studies showed that SB dose-dependently increased shrimp body weight and decreased feed conversion ratio. We found that SB protected against Vibrio parahaemolyticus as evidenced by survival rate, bacterial load, and hepatopancreatic pathology in shrimp. Finally, we explored the likely mechanism by which SB affects growth performance and vibriosis in shrimp. The 16S rRNA sequencing data showed that SB increased 6 probiotic genera and decreased 6 genera of pathogenic bacteria in shrimp. Among these, SB increased the proportion of Lactobacillus johnsonii and decreased that of V. parahaemolyticus in shrimp guts. To dissect the relationship among SB, Lactobacillus and Vibrio, we investigated the in vitro regulation of Lactobacillus and Vibrio by SB. SB at ≥ 0.25 μg/mL promoted L. johnsonii growth. Additionally, L. johnsonii and its supernatant could inhibit V. parahaemolyticus. Furthermore, SB could up-regulate five anti-Vibrio metabolites of L. johnsonii, which caused bacterial membrane destruction. In parallel, we identified 3 fatty acids as active compounds from SB. Overall, this work demonstrated that SB improved growth performance and vibriosis protection in shrimp via the regulation of gut microbiota.
Topics: Animals; Penaeidae; Vibrio parahaemolyticus; Vibrio Infections; Lactobacillus; RNA, Ribosomal, 16S; Vibrio; Probiotics
PubMed: 38773245
DOI: 10.1038/s41598-024-62436-x -
Aquatic Toxicology (Amsterdam,... Jul 2024As one of the main components of marine pollution, microplastics (MPs) inevitably enter the mussel aquaculture environment. At the same time, pathogenic bacteria,...
As one of the main components of marine pollution, microplastics (MPs) inevitably enter the mussel aquaculture environment. At the same time, pathogenic bacteria, especially pathogens such as Vibrio, can cause illness outbreaks, leading to large-scale death of mussels. The potential harm of MPs and pathogenic bacteria to bivalve remains unclear. This study designed two experiments (1) mussels (Mytilus galloprovincialis) were exposed to 100 particles/L or 1,000 particles/L polymethyl methacrylate (PMMA, 17.01 ± 6.74 μm) MPs and 1 × 10 CFU/mL Vibrio parahaemolyticus at the same time (14 days), and (2) mussels were exposed to 100 particles/L or 1,000 particles/L MPs for a long time (30 days) and then exposed to 1 × 10 CFU/mL V. parahaemolyticus to explore the effects of these two stresses on the mussel immune system. The results showed that after the combined exposure of V. parahaemolyticus and MPs, the lysosomal membrane stability of hemocytes decreased, lysozyme activity was inhibited, and hemocytes were induced to produce more lectins and defensins to fight pathogenic invasion. Long-term exposure to MPs caused a large amount of energy consumption in mussels, inhibited most of the functions of humoral immunity, increased the risk of mussel infection with pathogenic bacteria, and negatively affected mussel condition factor, the number of hemocytes, and the number of byssuses. Mussels may allocate more energy to deal with MPs and pathogenic bacterial infections rather than for growth. Above all, MPs exposure can affect mussel immune function or reduce its stress resistance, which in turn has an impact on mollusk farming.
Topics: Animals; Mytilus; Microplastics; Vibrio parahaemolyticus; Water Pollutants, Chemical; Hemocytes; Muramidase; Immune System
PubMed: 38768528
DOI: 10.1016/j.aquatox.2024.106959 -
BioRxiv : the Preprint Server For... May 2024Bacteria and phages are locked in a co-evolutionary arms race where each entity evolves mechanisms to restrict the proliferation of the other. Phage-encoded defense...
UNLABELLED
Bacteria and phages are locked in a co-evolutionary arms race where each entity evolves mechanisms to restrict the proliferation of the other. Phage-encoded defense inhibitors have proven powerful tools to interrogate how defense systems function. A relatively common defense system is BREX (Bacteriophage exclusion); however, how BREX functions to restrict phage infection remains poorly understood. A BREX system encoded by the SXT integrative and conjugative element, Ind5, was recently identified in , the causative agent of the diarrheal disease cholera. The lytic phage ICP1 that co-circulates with encodes the BREX inhibitor OrbA, but how OrbA inhibits BREX is unclear. Here, we determine that OrbA inhibits BREX using a unique mechanism from known BREX inhibitors by directly binding to the BREX component BrxC. BrxC has a functional ATPase domain that, when mutated, not only disrupts BrxC function but also alters how BrxC multimerizes. Furthermore, we find that OrbA binding disrupts BrxC-BrxC interactions. We determine that OrbA cannot bind BrxC encoded by the distantly related BREX system encoded by the SXT Ban9, and thus fails to inhibit this BREX system that also circulates in epidemic . Lastly, we find that homologs of the Ind5 BrxC are more diverse than the homologs of the Ban9 BrxC. These data provide new insight into the function of the BrxC ATPase and highlight how phage-encoded inhibitors can disrupt phage defense systems using different mechanisms.
IMPORTANCE
With renewed interest in phage therapy to combat antibiotic-resistant pathogens, understanding the mechanisms bacteria use to defend themselves against phages and the counter-strategies phages evolve to inhibit defenses is paramount. Bacteriophage exclusion (BREX) is a common defense system with few known inhibitors. Here, we probe how the vibriophage-encoded inhibitor OrbA inhibits the BREX system of , the causative agent of the diarrheal disease cholera. By interrogating OrbA function, we have begun to understand the importance and function of a BREX component. Our results demonstrate the importance of identifying inhibitors against defense systems, as they are powerful tools for dissecting defense activity and can inform strategies to increase the efficacy of some phage therapies.
PubMed: 38766029
DOI: 10.1101/2024.05.09.593382 -
The Science of the Total Environment Jul 2024Rapid urbanization has precipitated significant anthropogenic pollution (nutrients and pathogens) in urban rivers and their receiving systems, which consequentially...
Rapid urbanization has precipitated significant anthropogenic pollution (nutrients and pathogens) in urban rivers and their receiving systems, which consequentially disrupted the compositions and assembly of bacterial community within these ecosystems. However, there remains scarce information regarding the composition and assembly of both planktonic and benthic bacterial communities as well as pathogen distribution in such environments. In this study, full-length 16S rRNA gene sequencing was conducted to investigate the bacterial community composition, interactions, and assembly processes as well as the distribution of potential pathogens along a riverine-coastal continuum in Shenzhen megacity, China. The results indicated that both riverine and coastal bacterial communities were predominantly composed of Gammaproteobacteria (24.8 ± 12.6 %), Alphaproteobacteria (16.1 ± 9.8 %), and Bacteroidota (14.3 ± 8.6 %), while sedimentary bacterial communities exhibited significantly higher diversity compared to their planktonic counterparts. Bacterial community patterns exhibited significant divergences across different habitats, and a significant distance-decay relationship of bacterial community similarity was particularly observed within the urban river ecosystem. Moreover, the urban river ecosystem displayed a more complex bacterial co-occurrence network than the coastal ecosystem, and a low ratio of negative:positive cohesion suggested the inherent instability of these networks. Homogeneous selection and dispersal limitation emerged as the predominant influences on planktonic and sedimentary bacterial communities, respectively. Pathogenic genera such as Vibrio, Bacteroides, and Acinetobacter, known for their roles in foodborne diseases or wound infection, were also identified. Collectively, these findings provided critical insights into bacterial community dynamics and their implications for ecosystem management and pathogen risk control in riverine and coastal environments impacted by rapid urbanization.
Topics: China; Urbanization; Rivers; Bacteria; Ecosystem; RNA, Ribosomal, 16S; Environmental Monitoring; Microbiota; Cities; Water Microbiology
PubMed: 38761945
DOI: 10.1016/j.scitotenv.2024.173298 -
Vaccine May 2024Cholera is responsible for 1.3 to 4.0 million cholera cases globally and poses a significant threat, with Zambia reporting 17,169 cases as of 4th February 2024....
Cholera is responsible for 1.3 to 4.0 million cholera cases globally and poses a significant threat, with Zambia reporting 17,169 cases as of 4th February 2024. Recognizing the crucial link between natural cholera infections and vaccine protection, this study aimed to assess immune responses post cholera infection and vaccination. This was a comparative study consisting of 50 participants enrolled during a cholera outbreak in Zambia's Eastern Province and an additional 56 participants who received oral cholera vaccinations in Zambia's Central Province. Vibriocidal antibodies were plotted as geometric mean titres in the naturally infected and vaccinated individuals. A significant difference (p < 0.047) emerged when comparing naturally infected to fully vaccinated individuals (2 doses) on day 28 against V. cholerae Ogawa. Those who received two doses of the oral cholera vaccine had higher antibody titres than those who were naturally infected. Notably, the lowest titres occurred between 0-9 days post onset, contrasting with peak responses at 10-19 days. This study addresses a critical knowledge gap in understanding cholera immunity dynamics, emphasizing the potential superiority of vaccination-induced immune responses. We recommend post infection vaccination after 40 days for sustained immunity and prolonged protection, especially in cholera hotspots.
PubMed: 38760271
DOI: 10.1016/j.vaccine.2024.05.027 -
International Journal of Food... Jun 2024This study reports a comprehensive epidemiological and genetic analysis of V. cholerae strains, specifically non-O1/non-O139 serogroups, isolated from animal-derived...
This study reports a comprehensive epidemiological and genetic analysis of V. cholerae strains, specifically non-O1/non-O139 serogroups, isolated from animal-derived food samples in Guangdong province from 2015 to 2019. A total of 21 V. cholerae strains were obtained, which exhibited high resistance rates for nalidixic acid (57.14 %, 12/21), ampicillin (33.33 %, 7/21), and ciprofloxacin (19.05 %, 4/21). The quinolone resistance-related gene, qnrVC, was prevalent in 80.95 % (17/21) of the isolates. Additionally, chromosomally mediated quinolone-resistance mutations, including mutations in GyrA at position 83 (S83I) and ParC at position 85 (S85L), were detected in 47.62 % of the isolates. The combination of target mutation and qnrVC genes was shown to mediate resistance or intermediate resistance to ciprofloxacin in V. cholerae. Furthermore, an IncC-type conjugative plasmid carrying thirteen antibiotic resistance genes, including genes conferring resistance to two clinically important antibiotics, cephalosporins and fluoroquinolones, was identified in the shrimp-derived strain Vc516. While none of our food isolates harbored the toxigenic CTX- and TCP-encoding genes, they did possess genes encoding toxins such as HlyA and Autoinducer-2. Notably, some V. cholerae strains from this study exhibited a close genetic relationship with clinical strains, suggesting their potential to cause human infections. Taken together, this study provides a comprehensive view of the epidemiological features and genetic basis of antimicrobial resistance and virulence potential of V. cholerae strains isolated from food in southern China, thereby advancing our understanding of this important pathogen.
Topics: China; Drug Resistance, Multiple, Bacterial; Food Microbiology; Anti-Bacterial Agents; Animals; Humans; Microbial Sensitivity Tests; Cholera; Vibrio cholerae; Vibrio cholerae non-O1; Plasmids
PubMed: 38759293
DOI: 10.1016/j.ijfoodmicro.2024.110734