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Amino Acids Apr 2024In the face of increasing antimicrobial resistance in aquaculture, researchers are exploring novel substitutes to customary antibiotics. One potential solution is the...
In the face of increasing antimicrobial resistance in aquaculture, researchers are exploring novel substitutes to customary antibiotics. One potential solution is the use of antimicrobial peptides (AMPs). We aimed to design and evaluate a novel, short, and compositionally simple AMP with potent activity against various bacterial pathogens in aquaculture. The resulting peptide, KK12YW, has an amphipathic nature and net charge of + 7. Molecular docking experiments disclosed that KK12YW has a strong affinity for aerolysin, a virulence protein produced by the bacterial pathogen Aeromonas sobria. KK12YW was synthesized using Fmoc chemistry and tested against a range of bacterial pathogens, including A. sobria, A. salmonicida, A. hydrophila, Edwardsiella tarda, Vibrio parahaemolyticus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, and methicillin-resistant S. aureus. The AMP showed promising antibacterial activity, with MIC and MBC values ranging from 0.89 to 917.1 µgmL and 3.67 to 1100.52 µgmL, respectively. In addition, KK12YW exhibited resistance to high temperatures and remained effective even in the presence of serum and salt, indicating its stability. The peptide also demonstrated minimal hemolysis toward fish RBCs, even at higher concentrations. Taken together, these findings indicate that KK12YW could be a highly promising and viable substitute for conventional antibiotics to combat microbial infections in aquaculture.
Topics: Animals; Methicillin-Resistant Staphylococcus aureus; Molecular Docking Simulation; Antimicrobial Cationic Peptides; Anti-Bacterial Agents; Escherichia coli; Fishes; Microbial Sensitivity Tests
PubMed: 38578302
DOI: 10.1007/s00726-024-03388-4 -
Microbiology Spectrum May 2024is a genus of halophilic, gram-negative bacteria found in estuaries around the globe. Integral parts of coastal cultures often involve contact with vectors of...
UNLABELLED
is a genus of halophilic, gram-negative bacteria found in estuaries around the globe. Integral parts of coastal cultures often involve contact with vectors of pathogenic spp. (e.g., consuming raw shellfish). High rates of mortality from certain spp. infections demonstrate the need for an improved understanding of spp. dynamics in estuarine regions. Our study assessed meteorological, hydrographic, and biological correlates of and at 10 sites in the Eastern Mississippi Sound System (EMSS) from April to October 2019. During the sampling period, median abundances of and were 2.31 log MPN/L and 2.90 log MPN/L, respectively. spp. dynamics were largely driven by site-based variation, with sites closest to freshwater inputs having the highest abundances. The E-W wind scalar, which affects Ekman transport, was a novel spp. correlate observed. A potential salinity effect on bacterial-particle associations was identified, where was associated with larger particles in conditions outside of their optimal salinity. Additionally, abundances were correlated to those of harmful algal species that did not dominate community chlorophyll. Correlates from this study may be used to inform the next iteration of regionally predictive models and may lend additional insight to spp. ecology in similar systems.
IMPORTANCE
spp. are bacteria found in estuaries worldwide; some species can cause illness and infections in humans. Relationships between spp. abundance, salinity, and temperature are well documented, but correlations to other environmental parameters are less understood. This study identifies unique correlates (e.g., E-W wind scalar and harmful algal species) that could potentially inform the next iteration of predictive models for the EMSS region. Additionally, these correlates may allow existing environmental monitoring efforts to be leveraged in providing data inputs for future Vibrio risk models. An observed correlation between salinity and /particle-size associations suggests that predicted environmental changes may affect the abundance of spp. in certain reservoirs, which may alter which vectors present the greatest vibrio risk.
Topics: Vibrio parahaemolyticus; Vibrio vulnificus; Estuaries; Alabama; Population Dynamics; Salinity; Vibrio Infections; Seawater; Water Microbiology
PubMed: 38578091
DOI: 10.1128/spectrum.03674-23 -
Biofilm Jun 2024is widely distributed in marine ecosystems. Magnesium ion (Mg) is the second most abundant metal cation in seawater, and plays important roles in the growth and gene...
is widely distributed in marine ecosystems. Magnesium ion (Mg) is the second most abundant metal cation in seawater, and plays important roles in the growth and gene expression of . , but lacks the detailed mechanisms. In this study, the RNA sequencing data demonstrated that a total of 1494 genes was significantly regulated by Mg. The majority of the genes associated with lateral flagella, exopolysaccharide, type III secretion system 2, type VI secretion system (T6SS) 1, T6SS2, and thermostable direct hemolysin were downregulated. A total of 18 genes that may be involved in c-di-GMP metabolism and more than 80 genes encoding putative regulators were also significantly and differentially expressed in response to Mg, indicating that the adaptation process to Mg stress may be strictly regulated by complex regulatory networks. In addition, Mg promoted the proliferative speed, swimming motility and cell adhesion of , but inhibited the swarming motility, biofilm formation, and c-di-GMP production. However, Mg had no effect on the production of capsular polysaccharide and cytoxicity against HeLa cells. Therefore, Mg had a comprehensive impact on the physiology and gene expression of .
PubMed: 38577556
DOI: 10.1016/j.bioflm.2024.100194 -
PloS One 2024Vibrio parahaemolyticus is a marine bacterium that can infect and cause the death of aquatic organisms. V. parahaemolyticus can also cause human foodborne infection via...
Vibrio parahaemolyticus is a marine bacterium that can infect and cause the death of aquatic organisms. V. parahaemolyticus can also cause human foodborne infection via contaminated seafood, with clinical syndromes which include diarrhea, abdominal cramps, nausea and so on. Since controlling V. parahaemolyticus is important for aquaculture and human health, various strategies have been explored. This study investigates the application of antagonistic microorganisms to inhibit the growth of V. parahaemolyticus. We screened aquaculture environment samples and identified a Bacillus subtilis strain O-741 with potent antimicrobial activities. This strain showed a broad spectrum of antagonistic activities against V. parahaemolyticus and other Vibrio species. Application of the O-741 bacterium significantly increased the survival of Artemia nauplii which were infected with V. parahaemolyticus. Furthermore, the cell-free supernatant (CFS) of O-741 bacterium exhibited inhibitory ability against V. parahaemolyticus, and its activity was stable to heat, acidity, UV, enzymes, and organic solvents. Next, the O-741 CFS was extracted by ethyl acetate, and analyzed by ultra-performance liquid chromatography-mass-mass spectrometry (UPLC-MS/MS), and the functional faction was identified as an amicoumacin A compound. The organic extracts of CFS containing amicoumacin A had bactericidal effects on V. parahaemolyticus, and the treated V. parahaemolyticus cells showed disruption of the cell membrane and formation of cell cavities. These findings indicate that B. subtilis strain O-741 can inhibit the V. parahaemolyticus in vitro and in vivo, and has potential for use as a biocontrol agent for preventing V. parahaemolyticus infection.
Topics: Humans; Vibrio parahaemolyticus; Bacillus subtilis; Chromatography, Liquid; Tandem Mass Spectrometry; Anti-Bacterial Agents
PubMed: 38573920
DOI: 10.1371/journal.pone.0299015 -
Scientific Reports Apr 2024Cholera continues to represent a major public health concern in Ethiopia. The country has developed a Multi-sectoral National Cholera Elimination Plan in 2022, which...
Cholera continues to represent a major public health concern in Ethiopia. The country has developed a Multi-sectoral National Cholera Elimination Plan in 2022, which targets prevention and control interventions in cholera hotspots. Multiple methods to classify cholera hotspots have been used in several countries. Since 2014, a classification method developed by United Nations Children's Fund has been applied to guide water, sanitation and hygiene interventions throughout Sub-Saharan Africa based on three outbreak parameters: frequency, duration and standardized attack rate. In 2019, the Global Task Force on Cholera Control (GTFCC) proposed a method based on two parameters: average annual cholera incidence and persistence. In 2023, an updated GTFCC method for multisectoral interventions considers three epidemiological indicators (cumulative incidence, cumulative mortality and persistence,) and a cholera-case confirmation indicator. The current study aimed to classify cholera hotspots in Ethiopia at the woreda level (equivalent to district level) applying the three methods and comparing the results to optimize the hotspot targeting strategy. From 2015 to 2021, cholera hotspots were located along major routes between Addis Ababa and woredas adjacent to the Kenya and Somalia borders, throughout Tigray Region, around Lake Tana, and in Afar Region. The multi-method comparison enables decision makers to prioritize interventions according to a sub-classification of the highest-priority areas.
Topics: Child; Humans; Cholera; Ethiopia; Public Health; Disease Outbreaks; Sanitation
PubMed: 38570545
DOI: 10.1038/s41598-024-56299-5 -
Scientific Reports Apr 2024Since the onset of the seventh cholera pandemic, Ethiopia has been affected by recurrent epidemics. However, the epidemiology of cholera in this country remains poorly...
Since the onset of the seventh cholera pandemic, Ethiopia has been affected by recurrent epidemics. However, the epidemiology of cholera in this country remains poorly understood. This study aimed to describe cholera outbreak characteristics in Ethiopia from 2015 to 2021. During this period, Ethiopia experienced four epidemic waves. The first wave involved nationwide outbreaks during the second half of 2016 followed by outbreaks predominantly affecting Somali Region in 2017. The second wave primarily affected Tigray and Afar Regions. During the third wave, multiple smaller-scale outbreaks occurred during 2019. The fourth wave was limited to Bale Zone (Oromia Region) in 2021. Overall, a north to south shift was observed over the course of the study period. Major cholera transmission factors included limited access to safe water and sanitation facilities. Severe weather events (drought and flooding) appear to aggravate cholera diffusion. Cholera transmission between Ethiopia and nearby countries (Kenya and Somalia), likely plays a major role in regional cholera dynamics. Overall, this study provides the first understanding of recent spatiotemporal cholera dynamics in Ethiopia to inform cholera control and elimination strategies.
Topics: Humans; Cholera; Ethiopia; Epidemics; Disease Outbreaks; Kenya; Pandemics
PubMed: 38570534
DOI: 10.1038/s41598-024-51324-z -
BMC Veterinary Research Apr 2024Vibriosis is one of the most serious bacterial diseases and causes high morbidity and mortality among cultured sea breams. This study was undertaken to track the...
BACKGROUND
Vibriosis is one of the most serious bacterial diseases and causes high morbidity and mortality among cultured sea breams. This study was undertaken to track the surveillance of Vibrio infection and its correlation to environmental factors. A total of 115 gilthead sea breams were collected seasonally from a private earthen pond fish farm in the Shatta area of Damietta, Egypt from September 2022 to July 2023. Physicochemical parameters of water were analyzed, and heavy metal levels were measured. The fish samples were subjected to clinical, bacteriological, Enterobacterial Repetitive Intergenic Consensus (ERIC) fingerprinting, and hematoxylin and Eosin histopathological staining.
RESULTS
The results revealed significant variations in the water quality parameters over different seasons, in addition to an increase in heavy metals. Naturally infected fish showed external signs and postmortem lesions that were relevant to bacterial infection. Two dominant Vibrio subspecies of bacteria were identified: V. alginolyticus (205 isolates) and V. fluvialis (87 isolates). PCR confirmed the presence of V. alginolyticus using the species-specific primer collagenase at 737 bp. The highest prevalence of V. alginolyticus was detected during the summer season (57.72%), and the lowest prevalence was observed in autumn (39.75%). The correlation analysis revealed a positive relationship between V. alginolyticus and water temperature (r = 0.69). On the other hand, V. fluvialis showed a high prevalence during the autumn season (25.30%) and the lowest prevalence during the summer season (10.56%), where it was negatively correlated with water temperatures (r =-0.03). ERIC fingerprinting showed genetic variation within the Vibrio isolates. Antimicrobial susceptibility testing revealed sensitivity to ciprofloxacin and doxycycline, and resistance to amoxicillin and erythromycin. The multiple antibiotic resistance (MAR) index values for V. alginolyticus and V. fluvialis ranged from 0.3 to 0.7, with a multi-drug resistance pattern to at least three antibiotics. Histopathological alterations in the affected tissues revealed marked hemorrhage, vascular congestion, and hemosiderosis infiltration.
CONCLUSION
This study provides insights into the potential propagation of waterborne diseases and antibiotic resistance in the environment. Ensuring that the environment does not serve as a reservoir for virulent and contagious Vibrio species is a critical concern for regional aquaculture industries. Therefore, we recommend implementing environmental context-specific monitoring and surveillance tools for microbial resistance.
Topics: Animals; Sea Bream; Prevalence; Egypt; Drug Resistance, Bacterial; Vibrio; Anti-Bacterial Agents; Vibrio Infections; Genetic Variation
PubMed: 38561778
DOI: 10.1186/s12917-024-03978-0 -
BMC Infectious Diseases Mar 2024Since the early 1970s, cholera outbreaks have been a major public health burden in the Democratic Republic of Congo (DRC). Cholera cases have been reported in a... (Review)
Review
BACKGROUND
Since the early 1970s, cholera outbreaks have been a major public health burden in the Democratic Republic of Congo (DRC). Cholera cases have been reported in a quasi-continuous manner in certain lakeside areas in the Great Lakes Region. As these cholera-endemic health zones constitute a starting point for outbreaks and diffusion towards other at-risk areas, they play a major role in cholera dynamics in the country. Monitoring the spatiotemporal dynamics of cholera hotspots and adjusting interventions accordingly thus reduces the disease burden in an efficient and cost-effective manner.
METHODS
A literature review was conducted to describe the spatiotemporal dynamics of cholera in the DRC at the province level from 1973 to 1999. We then identified and classified cholera hotspots at the provincial and health zone levels from 2003 to 2022 and described the spatiotemporal evolution of hotspots. We also applied and compared three different classification methods to ensure that cholera hotspots are identified and classified according to the DRC context.
RESULTS
According to all three methods, high-priority hotspots were concentrated in the eastern Great Lakes Region. Overall, hotspots largely remained unchanged over the course of the study period, although slight improvements were observed in some eastern hotspots, while other non-endemic areas in the west experienced an increase in cholera outbreaks. The Global Task Force on Cholera Control (GTFCC) and the Department of Ecology and Infectious Disease Control (DEIDC) methods largely yielded similar results for the high-risk hotspots. However, the medium-priority hotspots identified by the GTFCC method were further sub-classified by the DEIDC method, thereby providing a more detailed ranking for priority targeting.
CONCLUSIONS
Overall, the findings of this comprehensive study shed light on the dynamics of cholera hotspots in the DRC from 1973 to 2022. These results may serve as an evidence-based foundation for public health officials and policymakers to improve the implementation of the Multisectoral Cholera Elimination Plan, guiding targeted interventions and resource allocation to mitigate the impact of cholera in vulnerable communities.
Topics: Humans; Cholera; Democratic Republic of the Congo; Disease Outbreaks; Public Health
PubMed: 38549076
DOI: 10.1186/s12879-024-09164-9 -
Microorganisms Mar 2024With rising infection rates in recent years, poses an increasing threat to public safety in the coastal brackish Baltic Sea. It is therefore important to monitor this...
With rising infection rates in recent years, poses an increasing threat to public safety in the coastal brackish Baltic Sea. It is therefore important to monitor this organism and assess the infection risk on a more regular basis. However, as the coastline of the Baltic Sea is 8000 km long and shared by nine nations, a convenient, fast, inexpensive, yet efficient identification method is essential. We evaluated the effectiveness of a two-step agar-based approach consisting of successive isolation and cultivation on thiosulphate-citrate-bile salt sucrose (TCBS) agar and CHROMagar™ for in comparison with , , and . Our study contains isolates from water and sediment across a broad expanse of the Baltic Sea including 13 locations and two different summers, the time of year during which infections are usually much more frequent. Confirmation of isolate species identity was carried out using molecular analyses. The two-step agar plating method performed well across different locations and timeframes in correctly identifying by more than 80%, but the sensitivity in other species varied. Thus, our approach yielded promising results as a potential tool for early detection across a broad timeframe and transect of the Baltic Sea and potentially other brackish environments.
PubMed: 38543665
DOI: 10.3390/microorganisms12030614 -
Microorganisms Feb 2024Spotted sea bass () is a high-economic-value aquacultural fish widely distributed in the coastal and estuarine areas of East Asia. In August 2020, a sudden outbreak of...
Spotted sea bass () is a high-economic-value aquacultural fish widely distributed in the coastal and estuarine areas of East Asia. In August 2020, a sudden outbreak of disease accompanied by significant mortality was documented in reared in marine cage cultures located in Nanhuang island, Yantai, China. Two coinfected bacterial strains, namely, NH-LM1 and NH-LM2, were isolated from the diseased for the first time. Through phylogenetic tree analysis, biochemical characterization, and genomic investigation, the isolated bacterial strains were identified as and subsp. , respectively. The genomic analysis revealed that possesses two circular chromosomes and six plasmids, while subsp. possesses two circular chromosomes and two plasmids. Furthermore, pathogenic genes analysis identified 587 and 484 genes in and subsp. , respectively. Additionally, drug-sensitivity testing demonstrated both and subsp. exhibited sensitivity to chloramphenicol, ciprofloxacin, ofloxacin, orfloxacin, minocycline, doxycycline, tetracycline, and ceftriaxone. Moreover, antibiotic resistance genes were detected in the plasmids of both strains. Extracellular product (ECP) analysis demonstrated that both and subsp. can produce hemolysin and amylase, while additionally can produce caseinase and esterase. Furthermore, infected fish displayed severe histopathological alterations, including infiltration of lymphocytes, cellular degeneration and necrosis, and loose aggregation of cells. Artificial infection assays determined that the LD of subsp. was 3 × 10 CFU/g, while the LD of was too low to be accurately evaluated. Furthermore, the dual infection of and subsp. elicits a more rapid and pronounced mortality rate compared to single challenge, thereby potentially exacerbating the severity of the disease through synergistic effects. Ultimately, our findings offer compelling evidence for the occurrence of coinfections involving and subsp. in , thereby contributing to the advancement of diagnostic and preventative measures for the associated disease.
PubMed: 38543554
DOI: 10.3390/microorganisms12030503