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Microbiology Spectrum Apr 2024, an aquatic pathogenic bacterium, has been found to infect many fish species and cause huge aquaculture losses. Antibiotics are the most common drugs used to treat...
, an aquatic pathogenic bacterium, has been found to infect many fish species and cause huge aquaculture losses. Antibiotics are the most common drugs used to treat these infections. However, antibiotic abuse can lead to the development of antibiotic resistance. Probiotics have the potential to replace antibiotics for preventing infections. Zebrafish () is a model organism used to study the innate immune system and host-pathogen interactions. Currently, there is little information on how the fish immune system responds to and probiotic treatment. To increase the understanding of the molecular mechanisms behind the zebrafish defense against and provide evidence that antibiotics can be replaced by probiotics, a transcriptome analysis of the zebrafish spleen was conducted 48 hours after infection by , as well as after treatment using KUST48 4 hours after infection. A total of 36,499 genes were obtained. There were 3,337 genes found to have significant differential expression between treatment and control groups. According to further annotation and enrichment analysis, differentially expressed genes (DEGs) were involved in signal transduction, endocrine system cancer, and the immune system. Insulin resistance disappeared in the zebrafish after treatment. Quantitative real-time PCR was performed to confirm the significant regulation of immune defense DEGs, the results of which were consistent with the RNA-sequencing data. These results could serve as a basis for future studies on the immune response to and provide suggestions for probiotic alternatives to antibiotics, which will be of great significance to aquaculture and environmental protection.IMPORTANCEIn recent years, the unreasonable use of antibiotics has led to the emergence of drug-resistant pathogenic bacteria, antibiotic residues, cross infection, toxic side effects, and so on, which has caused a serious threat to human food safety and life health. In recent years, many studies have demonstrated the potential of probiotics as a substitute for antibiotics, but there is still a lack of understanding of the molecular mechanisms underlying probiotic therapy. We conduct a research on the impact of KUST48 on the transcription profile of -infected zebrafish spleen. Mortality of zebrafish infected with was significantly reduced after treatment with KUST48. Our results can help to strengthen our understanding of the pathogenic mechanisms of zebrafish and provide a valuable reference for the molecular mechanisms of probiotic therapy.
Topics: Animals; Humans; Zebrafish; Aeromonas hydrophila; Lactococcus lactis; Spleen; Anti-Bacterial Agents; Gram-Negative Bacterial Infections; Fish Diseases
PubMed: 38441470
DOI: 10.1128/spectrum.03927-23 -
Antimicrobial Resistance and Infection... Mar 2024Aeromonas hydrophila infections can cause gastrointestinal symptoms such as diarrhea; however, deep infections are rarely reported. Outbreaks of A. hydrophila are...
BACKGROUND
Aeromonas hydrophila infections can cause gastrointestinal symptoms such as diarrhea; however, deep infections are rarely reported. Outbreaks of A. hydrophila are reported more frequently in fish, poultry, and snakes than in humans. This study aimed to track clonal relatedness of deep infections caused by A. hydrophila using whole genome sequencing (WGS).
METHODS
We collected three isolates of A. hydrophila in July 19 to August 29, 2019, from patients that underwent spine surgery. Accurate species identification was performed using whole-genome average nucleotide identity (ANI). Antimicrobial susceptibility testing was performed using a VITEK 2 automated AST-N334 Gram-negative susceptibility card system. Antimicrobial resistance and virulence genes were identified using the Comprehensive Antibiotic Resistance Database and Virulence Factor Database VFanalyzer.
RESULTS
All three isolates were identified as A. hydrophila based on ANI and multilocus sequence typing analysis revealed that A. hydrophila belonged to a novel sequence type (ST1172). All three isolates were susceptible to amikacin and levofloxacin; however, they were resistant to piperacillin/tazobactam, ceftriaxone, cefuroxime, cefoxitin, and imipenem. Isolate 19W05620 (patient 3) showed increased ceftazidime resistance (minimum inhibitory concentration ≥ 64 µg/mL). All three isolates possessed the same chromosomally encoded β-lactamases, including bla (β-lactamase), imiH (metallo-β-lactamase), and bla (AmpC) in plasmids.
CONCLUSIONS
Our study validated the transmission of a novel carbapenem-resistant A. hydrophila sequence type (ST1172) in patients that underwent spine surgery. Control measures should be developed to prevent dissemination of A. hydrophila in the hospital setting.
Topics: Animals; Humans; Aeromonas hydrophila; Amikacin; Carbapenems; beta-Lactamases; Anti-Infective Agents
PubMed: 38433212
DOI: 10.1186/s13756-023-01339-4 -
PloS One 2024The rapid and accurate detection of pathogenic bacteria is essential for food safety and public health. Conventional detection techniques, such as nucleic acid...
The rapid and accurate detection of pathogenic bacteria is essential for food safety and public health. Conventional detection techniques, such as nucleic acid sequence-based amplification and polymerase chain reaction, are time-consuming and require specialized equipment and trained personnel. Here, we present quick, disposable impedance sensors based on the novel hybrid MoS2 nanomaterial for detecting Escherichia coli DNA. Our results indicate that the proposed sensors operate linearly between 10- 20 and 10-15 M concentrations, achieving an impressive detection limit of 10-20 M with the highest sensitivity observed at a 0.325 nM probe concentration sensor. Furthermore, the electrochemical impedance spectroscopy biosensors exhibited potential selectivity for Escherichia coli DNA over Bacillus subtilis and Vibrio proteolyticus DNA sequences. The findings offer a promising avenue for efficient and precise DNA detection, with potential implications for broader biotechnology and medical diagnostics applications.
Topics: Electric Impedance; Molybdenum; Aeromonas hydrophila; DNA; Escherichia coli; Biosensing Techniques; Electrochemical Techniques
PubMed: 38422053
DOI: 10.1371/journal.pone.0299272 -
Microorganisms Feb 2024, a Gram-negative bacterium widely found in freshwater environments, acts as a common conditional pathogen affecting humans, livestock, and aquatic animals. In this...
, a Gram-negative bacterium widely found in freshwater environments, acts as a common conditional pathogen affecting humans, livestock, and aquatic animals. In this study, the impact of oridonin, an -kaurane diterpenoid compound derived from , on the virulence factors of AS 1.1801 and its antibacterial mechanism was elucidated. The minimum inhibitory concentration (MIC) of oridonin against AS 1.1801 was 100 μg/mL. Oridonin at inhibitory concentrations could significantly increase the electrical conductivity in the supernatant and escalate nucleic acid leakage ( < 0.01). This effect was concomitant with observed distortions in bacterial cells, the formation of cytoplasmic cavities, cellular damage, and pronounced inhibition of protein and nucleic acid synthesis. Additionally, oridonin at inhibitory levels exhibited a noteworthy suppressive impact on AS 1.1801 across biofilm formation, motility, hemolytic activity, lipase activity, and protease activity ( < 0.05), demonstrating a dose-dependent enhancement. qRT-PCR analysis showed that the gene expression of , and were significantly downregulated after oridonin treatment in AS 1.1801 ( < 0.05). Our results indicated that oridonin possessed significant antibacterial and anti-virulence effects on AS 1.1801.
PubMed: 38399819
DOI: 10.3390/microorganisms12020415 -
Microorganisms Jan 2024The oral cavity of snakes serves as a habitat for various microorganisms, some of which may include potential zoonotic pathogens posing risks to hosts and causing wound...
The oral cavity of snakes serves as a habitat for various microorganisms, some of which may include potential zoonotic pathogens posing risks to hosts and causing wound infections in snakebite victims. Clinical studies on snakebite cases in Taiwan have identified specific pathogens, such as (Gram-positive), , , and (Gram-negative). However, the prevalence of these bacteria in the oral cavity of wild snakes remains largely unknown. This study investigated the occurrence of these bacteria in six wild snake species (, , , , , and ) from southern Taiwan, along with factors influencing their presence. Oropharyngeal swab samples were collected from a substantial number of wild-caught snakes ( = 1104), followed by DNA extraction, polymerase chain reaction, and gel electrophoresis. The band positions of samples were compared with positive and negative controls to determine the presence of target bacteria in each sample. The overall occurrence rates were 67.4% for , 31.5% for , 8.2% for , and 7.7% for . Among snake species, exhibited dominance in (93.4%), (17.1%), and (14.5%), while male showed dominance in (51.3%). The occurrence of was lowest in winter. The results of multiple logistic regression analyses suggest that factors such as species, sex, temperature, season, and coexisting pathogens may have a significant impact on the occurrence of target bacteria. These findings have implications for wildlife medicine and snakebite management.
PubMed: 38399667
DOI: 10.3390/microorganisms12020263 -
Foods (Basel, Switzerland) Feb 2024Bivalves can concentrate biological and chemical pollutants, causing foodborne outbreaks whose occurrence is increasing, due to climatic and anthropic factors that are...
Bivalves can concentrate biological and chemical pollutants, causing foodborne outbreaks whose occurrence is increasing, due to climatic and anthropic factors that are difficult to reverse, hence the need for improved surveillance. This study aimed to evaluate the hygienic qualities of bivalves sampled along the production and distribution chain in Sicily and collect useful data for consumer safety. Bacteriological and molecular analyses were performed on 254 samples of bivalves for the detection of enteropathogenic , spp., spp., spp., and beta-glucuronidase-positive . A total of 96 out of 254 samples, collected in the production areas, were processed for algal biotoxins and heavy metals detection. Bacterial and algal contaminations were also assessed for 21 samples of water from aquaculture implants. spp., spp., , spp., and were detected in 106/254, 79/254, 12/254, 16/254, and 95/254 molluscs, respectively. A total of 10/96 bivalves tested positive for algal biotoxins, and metals were under the legal limit. , and were detected in 5, 3, and 3 water samples, respectively. , , and spp. were detected in water samples collected with the biotoxin-containing molluscs. Traces of yessotoxins were detected in molluscs from water samples containing the corresponding producing algae. Despite the strict regulation by the European Commission over shellfish supply chain monitoring, our analyses highlighted the need for efficiency improvement.
PubMed: 38397529
DOI: 10.3390/foods13040552 -
Antibiotics (Basel, Switzerland) Feb 2024spp. are environmental bacteria able to infect animals and humans. Here, we aim to evaluate the role of biofilms in persistence in freshwater. were isolated from...
spp. are environmental bacteria able to infect animals and humans. Here, we aim to evaluate the role of biofilms in persistence in freshwater. were isolated from water and biofilm samples and identified by Vitek-MS and sequencing. Antibiotic susceptibility profiles were determined according to EUCAST, and a crystal violet assay was used to assess biofilm assembly. MTT and the enumeration of colony-forming units were used to evaluate biofilm and planktonic susceptibility to chlorination, respectively. Identification at the species level was challenging, suggesting the need to improve the used methodologies. Five different species (, , , and ) were identified from water, and one species was identified from biofilms (). and presented resistance to different antibiotics, whith the highest resistance rate observed for (multiple antibiotic resistance index of 0.25). Of the 21 isolates, 11 were biofilm producers, and 10 of them were strong biofilm producers (SBPs). The SBPs presented increased tolerance to chlorine disinfection when compared with their planktonic counterparts. In order to elucidate the mechanisms underlying biofilm tolerance to chlorine and support the importance of preventing biofilm assembly in water reservoirs, further research is required.
PubMed: 38391552
DOI: 10.3390/antibiotics13020166 -
Frontiers in Nutrition 2024A 12-week feeding trial was conducted to evaluate the effects of replacing soybean meal with different types of rapeseed meal (RSM; Chinese 95-type (oil press model)...
High replacement of soybean meal by different types of rapeseed meal is detrimental to rainbow trout () growth, antioxidant capacity, non-specific immunity and tolerance.
A 12-week feeding trial was conducted to evaluate the effects of replacing soybean meal with different types of rapeseed meal (RSM; Chinese 95-type (oil press model) rapeseed meal [C95RM], Chinese 200-type rapeseed meal [C200RM], cold pressed rapeseed cake [CPRC], Indian rapeseed meal [IRM] and Canadian rapeseed meal [CRM]) on growth, antioxidant capacity, non-specific immunity and infection tolerance in 990 fingering (average weight 12.77 ± 0.01 g) rainbow trout (). A basal diet was prepared using fishmeal and soybean meal as the main protein sources, the other 10 diets were formulated with five types of RSM at 20% (C95RM20, C200RM20, CPRC20, IRM20, CRM20) or 35% (C95RM35, C200RM35, CPRC35, IRM35, CRM35) inclusion levels to replace iso-nitrogenous soybean meal. Regardless of the RSM source, dietary inclusion of 20% RSM significantly reduced the weight gain rate (WGR) and digestive enzymes activities (except C200RM20) of fish, but increased the blood urea nitrogen (BUN) and hepatic malondialdehyde (MDA) content (except CRM20). Fish fed with CPRC20 and IRM20 exhibited relatively higher plasma cortisol and MDA content, but lower content/activities of triiodothyronine (T), thyroxine (T) and glutathione peroxidase (GPx) in plasma, lysozyme (LZM) and complement 3 (C3) in serum, catalase (CAT) in liver, and respiratory burst activity (RBA) of head kidney macrophages. The intestinal and hepatic tissues fed with 20% RSM were damaged to some extent, with the CPRC20 and IRM20 groups being the most severely affected. Regardless of the RSM source, dietary inclusion of 35% RSM significantly decreased WGR and digestive enzymes activities, but significantly increased plasma BUN and MDA content. The fish fed with CPRC35 and IRM35 exhibited relatively higher plasma cortisol, MDA, serum triglyceride, BUN content, but lower content/activities of T, T, C3, and LZM in serum, CAT, peroxidase and GPx in plasma, CAT in liver, RBA and phagocytic activity of head kidney macrophage. The hepatic and intestinal tissues damage was the worst in the IRM35 group among the 35% RSM inclusion groups. These results indicate that including ≥20% RSM in the diet, regardless of the source, reduced the growth, antioxidant capacity, immunity, and survival to infection in rainbow trout.
PubMed: 38379546
DOI: 10.3389/fnut.2024.1363411 -
Applied Microbiology and Biotechnology Feb 2024Aeromonas is the main pathogen causing bacterial diseases in fish. The disadvantages of chemical drugs to control fish diseases have been highlighted, and it is urgent...
Aeromonas is the main pathogen causing bacterial diseases in fish. The disadvantages of chemical drugs to control fish diseases have been highlighted, and it is urgent to find an eco-friendly control method. In this study, an actinomycete strain with antibacterial activity against fish pathogenic bacteria was screened from soil samples. Combined with morphological characteristics, physiological and biochemical characteristics, and gyrB gene and whole genome comparison analysis, it was identified as a new strain of Streptomyces enissocaesilis, named Streptomyces enissocaesilis L-82. The strain has broad-spectrum antibacterial activity against fish pathogens. A substance with a mass-to-charge ratio of 227.20 [M + H] was isolated and purified by high-performance liquid chromatography and mass spectrometry. It was presumed to be a derivative of 5-dimethylallylindole-3-acetonitrile. The strain is safe and non-toxic to crucian carp, and can stably colonize crucian carp and inhibit the proliferation of A. hydrophila. After feeding the feed containing 1 × 10 CFU/mL strain concentration, the weight growth rate and specific growth rate of crucian carp increased, the activity of ACP and SOD in serum increased, and the survival rate of crucian carp increased after challenge. Genome-wide analysis showed that the strain had strong ability to metabolize and tolerate extreme environments. And has a strong potential for disease resistance. Therefore, the strain is expected to be developed as a feed additive for fish farming. KEY POINTS: • The new Streptomyces enissocaesilis L-82 has a broad spectrum and stable antibacterial activity and meets the safety standards of feed additives. • Strain L-82 can colonize crucian carp, improve the growth, antioxidant, and immune performance of the host, and improve the survival rate after being infected with A. hydrophila. • Genome-wide analysis suggests that the strain has great disease resistance potential and is expected to be developed as a feed additive for fish culture.
Topics: Animals; Goldfish; Disease Resistance; Carps; Anti-Bacterial Agents; Streptomyces
PubMed: 38372806
DOI: 10.1007/s00253-024-13031-7 -
Frontiers in Cellular and Infection... 2024and methicillin-resistant (MRSA) are potent bacterial pathogens posing major hazards to human health via consuming fish harboring these pathogens or by...
INTRODUCTION
and methicillin-resistant (MRSA) are potent bacterial pathogens posing major hazards to human health via consuming fish harboring these pathogens or by cross-contamination beyond the contaminated environment. The aim of this study was to determine risk variables associated with the presence of certain pathogenic bacteria from fish in retail markets in Egypt. The virulence genes of and were also studied. Furthermore, the antibiotic sensitivity and multidrug resistance of the microorganisms were evaluated.
METHODS
In a cross-sectional investigation, 370 samples were collected from mullet skin and muscle samples, washing water, fish handlers, knives, and chopping boards. Furthermore, fish handlers' public health implications were assessed via their response to a descriptive questionnaire.
RESULTS
and species dominated the investigated samples with percentages of 26.76% and 30.81%, respectively. Furthermore, and MRSA were the predominant recovered bacterial pathogens among washing water and knives (53.85% and 46.66%, respectively). The virulence markers and were found in 90.7% and 46.5% of isolates, respectively. Moreover, the virulence genes and were prevalent in 80% and 60% of isolates, respectively. Antimicrobial susceptibility results revealed that all isolates were resistant to amoxicillin and all MRSA isolates were resistant to amoxicillin and ampicillin. Remarkably, multiple drug resistance (MDR) patterns were detected in high proportions in (88.37%) and MRSA (100%) isolates. The prevalence of spp. and had a positive significant correlation with the frequency of handwashing and use of sanitizer in cleaning of instruments. MRSA showed the highest significant prevalence rate in the oldest age category.
CONCLUSION
The pathogenic bacteria recovered in this study were virulent and had a significant correlation with risk factors associated with improper fish handling. Furthermore, a high frequency of MDR was detected in these pathogenic bacteria, posing a significant risk to food safety and public health.
Topics: Animals; Humans; Methicillin-Resistant Staphylococcus aureus; Staphylococcus aureus; Aeromonas hydrophila; Cross-Sectional Studies; Anti-Bacterial Agents; Fishes; Smegmamorpha; Aeromonas; Amoxicillin; Risk Factors; Water; Microbial Sensitivity Tests; Staphylococcal Infections
PubMed: 38371296
DOI: 10.3389/fcimb.2024.1348973