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Heliyon Apr 2020Agricultural drainage ditches represent a major source of nutrient pollution. Shifts in nitrogen source and use of animal manures have changed the bacterial composition...
Agricultural drainage ditches represent a major source of nutrient pollution. Shifts in nitrogen source and use of animal manures have changed the bacterial composition both in species of bacteria and their abundance in agricultural ditches. This change affects how nitrogen is being cycled and potentially the final forms of available nutrients. In particular, animal manures often have bacteria such as present, increasing the abundance of a bacterial species in ditches. Research has shown that the effect of different nitrogen sources is to change bacterial community composition (class, family). How this influences the role of an individual bacterial species is poorly understood. Thus, our question was how individual species would respond to different sources of nitrogen. We used , and that are common in agricultural ditches and exposed them to different concentrations of nitrogen in cultures of 1 × 10 and 1 × 10 dilutions from a stock solution of bacteria. Nitrogen sources were ammonium chloride, sodium nitrate and urea. The results showed and have strong similarities particularly with nitrate-N and urea-N utilization and the response was often correlated with the amount of nutrient added. while similar did not show any strong correlation with amount of nutrient added. was different from the other three bacteria in utilization or production. Research has provided insight into the role of some bacteria in nitrogen cycling and may be valuable in the future to developing management strategies to reduce nutrients.
PubMed: 32322713
DOI: 10.1016/j.heliyon.2020.e03711 -
PeerJ 2023Tilapia is a primary aquaculture fish in Thailand, but little is known about the occurrence of antimicrobial resistance (AMR) in , spp., and colonizing healthy tilapia...
BACKGROUND
Tilapia is a primary aquaculture fish in Thailand, but little is known about the occurrence of antimicrobial resistance (AMR) in , spp., and colonizing healthy tilapia intended for human consumption and the co-occurrence of these AMR bacteria in the cultivation water.
METHODS
This study determined the phenotype and genotype of AMR, extended-spectrum -lactamase (ESBL) production, and virulence factors of , spp., and isolated from hybrid red tilapia and cultivation water in Thailand. Standard culture methods such as USFDA's BAM or ISO procedures were used for the original isolation, with all isolates confirmed by biochemical tests, serotyping, and species-specific gene detection based on PCR.
RESULTS
A total of 278 isolates consisting of 15 , 188 spp., and 75 isolates were retrieved from a previous study. All isolates of and isolates were resistance to at least one antimicrobial, with 26.7% and 72.3% of the isolates being multidrug resistant (MDR), respectively. All isolates were resistant to ampicillin (100%), followed by oxytetracycline (26.7%), tetracycline (26.7%), trimethoprim (26.7%), and oxolinic acid (20.0%). The predominant resistance genes in were (20.0%), followed by 13.3% of isolates having , , , , and isolates also exhibited a high prevalence of resistance to ampicillin (79.3%), oxolinic acid (75.5%), oxytetracycline (71.8%), chloramphenicol (62.8%), and florfenicol (55.3%). The most common resistance genes in these isolates were (65.4%), (64.9%), (63.8%), and (55.9%). All isolates were susceptible to all antimicrobials tested, while the most common resistance gene was (12.0%). One isolate of was positive for , while all isolates of and isolates were negative for integrons and . None of the bacterial isolates in this study were producing ESBL. The occurrence of (20.0%) in these isolates from tilapia aquaculture may signify a serious occupational and consumer health risk given that colistin is a last resort antimicrobial for treatment of Gram-negative bacteria infections.
CONCLUSIONS
Findings from this study on AMR bacteria in hybrid red tilapia suggest that aquaculture as practiced in Thailand can select for ubiquitous AMR pathogens, mobile genetic elements, and an emerging reservoir of and colistin-resistant bacteria. Resistant and pathogenic bacteria, such as resistance to ampicillin and tetracycline, or MDR circulating in aquaculture, together highlight the public health concerns and foodborne risks of zoonotic pathogens in humans from cultured freshwater fish.
Topics: Animals; Aeromonas hydrophila; Ampicillin; Anti-Bacterial Agents; Colistin; Drug Resistance, Bacterial; Oxolinic Acid; Oxytetracycline; Tetracycline; Tilapia; Virulence Factors
PubMed: 36855429
DOI: 10.7717/peerj.14896 -
The Brazilian Journal of Infectious... 2019Aeromonas species are renowned enteric pathogens with virulence determinants linked to human diseases, such as gastroenteritis, skin, soft-tissue and muscle infections,...
INTRODUCTION
Aeromonas species are renowned enteric pathogens with virulence determinants linked to human diseases, such as gastroenteritis, skin, soft-tissue and muscle infections, and septicemia. A recent concern of resistance in this organism has emerged, especially the presence carbapenemases. Herein we describe a case series of emerging carbapenem-resistant Aeromonas species infection in our hospital in Cali, Colombia.
MATERIALS AND METHODS
Cases from 2012 to 2018 are reported. Clinical data was abstracted from the clinical charts and laboratory information. Phenotypic detection of resistance was identified using the VITEK®2 system (BioMérieux) and broth microdilution MicroScan WalkAway plus System (Beckman Coulter). CARBA NP-test and multiplex qPCR assay was performed in 11 isolates to identify genes encoding carbapenemases (bla bla bla and bla).
RESULTS
21 cases of Aeromonas infection in hospitalized patients with phenotypic resistance to carbapenems were studied. The median age was 50 years, 55% (12/21) were male, and 67% (14/21) were healthcare-associated infections (HAI). Aeromonas hydrophila was the most common species (19/21). Forty-three percent (9/21) of the patients were immunocompromised. The mortality was 33% (7/21), and in patients with bacteremia was 100%. Most patients received empirical treatment with meropenem and failed to this treatment. PCR amplification tests showed negative results for the carbapenemases analyzed.
CONCLUSION
Emerging phenotypic carbapenem-resistant infection has been seen in our hospital, most as HAI. High mortality was found, especially in immunocompromised patients and in those who failled empirical treatment with carbapenems. As the main carbapenemases tested were negative, carbapenem-resistant could be attributed to an intrinsic metallo-β-lactamase, CphA encoded by the cphA gene, possible hyperproduction of ampC β-lactamase and/or porins expression.
Topics: Adult; Aeromonas; Aged; Anti-Bacterial Agents; Carbapenems; Colombia; Cross-Sectional Studies; Female; Gram-Negative Bacterial Infections; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Phenotype; beta-Lactam Resistance; beta-Lactamases
PubMed: 31541615
DOI: 10.1016/j.bjid.2019.08.005 -
Heliyon Dec 2023The fish immune system, which consists of innate and adaptive immunologic processes, defends against viruses, bacteria, fungi, and parasites. The gut immunity is an...
The fish immune system, which consists of innate and adaptive immunologic processes, defends against viruses, bacteria, fungi, and parasites. The gut immunity is an integral part of the host immune system that controls immunological homeostasis, hosts' interactions with their microbiomes, and provides defence against a number of intestinal infections. , a facultative air-breathing fish, was experimentally infected with using intraperitoneal injection followed by bath challenge, and transcriptome data were used to examine the gut immune responses during disease progression and recovery from the diseased state without the use of medication. For the control or uninfected fish (FGC) and the infected fish that were kept for seven days (FGE1) and fifteen days (FGE2), separate water tanks were set up. Coding DNA sequences (CDS) for FGC and FGE1, FGC and FGE2, and FGE1 and FGE2 were analyzed for differential gene expression (DGE). The presence and expression of genes involved in the T cell receptor (TCR) signalling pathway, natural killer (NK) cell-mediated cytotoxicity pathway, and complement-mediated pathway, along with a large number of other immune-related proteins, and heat shock protein (HSPs) under various experimental conditions and its relationship to immune modulation of the fish gut was the primary focus of this study. Significant up-and-down regulation of these pathways shows that, in FGE1, the fish's innate immune system was engaged, whereas in FGE2, the majority of innate immune mechanisms were repressed, and adaptive immunity was activated. Expression of genes related to the immune system and heat-shock proteins was induced during this host's immunological response, and this information was then used to build a thorough network relating to immunity and the heat-shock response. This is the first study to examine the relationship between pathogenic bacterial infection, disease reversal, and modification of innate and adaptive immunity as well as heat shock response.
PubMed: 38130423
DOI: 10.1016/j.heliyon.2023.e22936 -
BMC Research Notes Nov 2023Eel (Anguilla bicolor bicolor) is an Indonesian export commodity. However, it is facing a problem related to Aeromonas hydrophila, which can cause motile aeromonas...
The potential of shallot skin powder and actinomycetes metabolites as antimicrobe and antibiofilm in the treatment of eel (Anguilla bicolor bicolor) infected with Aeromonas hydrophila.
BACKGROUND
Eel (Anguilla bicolor bicolor) is an Indonesian export commodity. However, it is facing a problem related to Aeromonas hydrophila, which can cause motile aeromonas septicemia (MAS) and produce biofilm formation. Problem with antibiotic resistance challenges the need of an alternative treatment. Therefore, it is important to explore a solution to treat infection and the biofilm formed by A. hydrophila.
OBJECTIVES
In this study, we used shallot skin powder and actinomycetes metabolite 20 PM as antimicrobe and antibiofilm to treated eels infected with A. hydrophila.
RESULTS
Shallot skin powder (6.25 g 100 g feed) and Actinomycetes 20 PM metabolite (2 mL 100 g feed) were found to be effective as antimicrobe and antibiofilm agent in treating eels infected with A. hydrophila. Eel treated with antibiotic, shallot skin powder, and actinomycetes metabolite had 80%, 66%, and 73% survival rates, respectively. Other indicators such as red blood cell count, hemoglobin, and hematocrit were increased, but white blood cell count and phagocytic activity were dropped. Biofilm destruction were analyzed using scanning electron microscopy to determined antibiofilm activity of actinomycetes metabolite against biofilm of A. Hydrophila.
CONCLUSIONS
Shallot skin powder and actinomycetes metabolite were potential to treat infection of A. hydrophila in eel as an alternative treatment to antibiotics.
Topics: Animals; Anguilla; Aeromonas hydrophila; Powders; Shallots; Actinobacteria; Actinomyces; Biofilms; Gram-Negative Bacterial Infections
PubMed: 37946241
DOI: 10.1186/s13104-023-06611-9 -
Frontiers in Microbiology 2022is an emerging waterborne and foodborne pathogen with pathogenicity to humans and warm water fishes, which severely threatens human health, food safety and aquaculture....
is an emerging waterborne and foodborne pathogen with pathogenicity to humans and warm water fishes, which severely threatens human health, food safety and aquaculture. A novel method for the rapid, accurate, and sensitive detection of pathogenic is still needed to reduce the impact on human health and aquaculture. In this work, we developed a rapid, accurate, sensitive, and visual detection method (dRAA-CRISPR/Cas12a), without elaborate instruments, integrating the dualplex recombinase-assisted amplification (dRAA) assay and CRISPR/Cas12a system to detect pathogenic expressing and/or virulence genes. The dRAA-CRISPR/Cas12a method has high sensitivity, which can rapidly detect (about 45 min) with the limit of detection in 2 copies of genomic DNA per reaction, and has high specificity for three pathogenic strains ( , , and ). Moreover, dRAA-CRISPR/Cas12a method shows satisfactory practicability in the analysis of the spiked human blood and stool and fish samples. These results demonstrate that our developed pathogenic detection method, dRAA-CRISPR/Cas12a, is a promising potential method for the early diagnosis of human infection and on-site detection of in food and aquaculture.
PubMed: 36274718
DOI: 10.3389/fmicb.2022.973996 -
Toxics Mar 2023Bacterial fish disease outbreaks are a key concern for aquaculture. Complementary feed additives such as immunostimulants can serve as an ideal solution for disease...
Bacterial fish disease outbreaks are a key concern for aquaculture. Complementary feed additives such as immunostimulants can serve as an ideal solution for disease prevention. Herein, we scrutinized the efficacy of exopolysaccharides (EPSs) from probiotic and EPS-mediated zinc oxide nanoparticles (EPS-ZnO NPs) for a diet to evaluate growth parameters, antioxidant enzyme activities, and immune stimulation together with disease resistance against and in Mozambique tilapia . Fish were separated into seven groups, with six experimental groups fed with EPS and EPS-ZnO NPs at 2, 5, and 10 mg/g and a control fed a basal diet. The fish ingesting feed supplemented with EPS and EPS-ZnO NPs at 10 mg/g showed improved growth performance. Cellular and humoral-immunological parameters were tested in serum and mucus after 15 and 30 days of feeding. These parameters were substantially enriched with a 10 mg/g diet ( < 0.05) of EPS and EPS-ZnO NPs in comparison with the control. Furthermore, the EPS and EPS-ZnO NP supplemental diet actively enhanced the antioxidant response (glutathione peroxidase, superoxide dismutase, and catalase). In addition, the supplemental diet of EPS and EPS-ZnO NPs lowered the death rate and improved the disease resistance of following assessment with and at 50 µL. Hence, the overall results suggest that the supplemental diet of EPS and EPS-ZnO NPs might be used to ensure aquaculture feed additives.
PubMed: 37112540
DOI: 10.3390/toxics11040313 -
Frontiers in Microbiology 2022, a ubiquitous bacterium in aquatic habitats with broad host ranges, has earned the nickname of a 'Jack-of-all-trades'. However, there is still a limited understanding...
, a ubiquitous bacterium in aquatic habitats with broad host ranges, has earned the nickname of a 'Jack-of-all-trades'. However, there is still a limited understanding of the mechanism of how this bacterium fit the competition with other species in dynamic surroundings. The type VI secretion system (T6SS) is macromolecular machinery found in Gram-negative bacteria's cell envelope that is responsible for bacterial killing and/or pathogenicity toward different host cells. In this study, the depression of T6SS under iron-limiting conditions was detected. The ferric uptake regulator (Fur) was then found to act as an activator of T6SS by directly binding to the Fur box region in A promoter in the T6SS gene cluster. The transcription of A was repressed in Δ. Moreover, the inactivation of Fur resulted in considerable defects in the interbacterial competition activity and pathogenicity of and . These findings provide the first direct evidence that Fur positively regulates the expression and functional activity of T6SS in Gram-negative bacteria and will help to understand the fascinating mechanism of competitive advantage for in different ecological niches.
PubMed: 36845974
DOI: 10.3389/fmicb.2022.1099611 -
Le Infezioni in Medicina Dec 2019Aeromonas hydrophila (A. hydrophila) occasionally causes necrotizing fasciitis (NF) and sepsis in immunocompromised hosts. NF is associated with high mortality. In cases...
Aeromonas hydrophila (A. hydrophila) occasionally causes necrotizing fasciitis (NF) and sepsis in immunocompromised hosts. NF is associated with high mortality. In cases of septic shock due to A. hydrophila, mortality is nearly 100%. Our 47-year-old male patient was diagnosed with NF and septic shock due to A. hydrophila. He had not been exposed to fresh or slightly salty water, which is where the bacterium is typically found, so its origin in this case is unclear. This is the first known case in which the patient was able to be completely cured without amputation. NF was suspected from his sepsis, medical history including alcoholic cirrhosis, and a severely poor general condition, but his skin lesions were mild. We promptly made an exploratory incision and debrided his legs. NF could then be diagnosed. At an early stage, A. hydrophila was recognized as a possible pathogen of NF because of the patient's medical background and the Gram stain findings of intraoperative exudate. Minocycline in addition to carbapenem and vancomycin plus clindamycin were administered as empiric therapy. When A. hydrophila was detected in the blood culture, ciprofloxacin was administered as definitive therapy. Successful treatment of NF requires early diagnosis, prompt debridement from onset and adequate empirical antibiotic therapy.
Topics: Aeromonas hydrophila; Fasciitis, Necrotizing; Gram-Negative Bacterial Infections; Humans; Male; Middle Aged; Remission Induction; Sepsis
PubMed: 31846994
DOI: No ID Found -
Microbiology Resource Announcements Feb 2022We report the complete genome sequence of Aeromonas hydrophila bacteriophage BUCT552 whose full length of the linear dsDNA genome is 59,685 bp and G+C content is...
We report the complete genome sequence of Aeromonas hydrophila bacteriophage BUCT552 whose full length of the linear dsDNA genome is 59,685 bp and G+C content is 60.0%. It contains 74 open reading frames but no tRNA. The results of TEM showed BUCT552 is a member of the family .
PubMed: 35175128
DOI: 10.1128/mra.01172-21