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F1000Research 2023Strategies to increase body resistance and prevent disease in aquaculture include using vaccines, antibiotics, and probiotics. Today, the use of antibiotics with...
Strategies to increase body resistance and prevent disease in aquaculture include using vaccines, antibiotics, and probiotics. Today, the use of antibiotics with natural ingredients is becoming a trend. One of the natural ingredients that contain high antioxidants and antibiotics is sp. This research was conducted from March to May 2022 at the Biotechnology Laboratory, Faculty of Fisheries and Marine, Universitas Riau, in two stages: 1) the sensitivity of extracts of sp. and 2) the application of sp. extract orally in tilapia ( ). The parameters measured were clear zone, minimum inhibitory concentration, LD test of leaf extract of sp. in tilapia ( ), hemoglobin levels, hematocrit, total leukocytes, total erythrocytes, leukocyte differentiation, and survival rate. Data on hematology parameters were tabulated and analyzed using a One-Way ANOVA followed by a Student Newman Keuls (SNK) test when deemed necessary. The results showed that the extract of sp. inhibited the growth of bacteria with a clear zone of 6.5-15.0 mm, which is classified as resistant. At doses of 2000, 2500, and 3000 ppm, it did not cause death in fish for 96 hours (LD ). Hematological parameters can be a sign of the health status of fish. Tilapia given sp. in different doses gave an effect between treatments, both after 30 days of rearing and post-test against bacteria (p<0.05). The results showed that the hematology of fish fed with sp. extract was in the normal or healthy range. Healthy tilapia had erythrocyte counts ranging from 1.34-2.11×10 cells/mm , hematocrit 26.17-33.19%, hemoglobin 6.26-11.2 g/dL and total leukocytes 1.01-1.50×10 cells/mm and total erythrocytes 5.88-9.13×10 cells/ mm . A dose of 3000 ppm provided the highest health improvement against bacterial infection.
Topics: Animals; Sargassum; Cichlids; Aeromonas hydrophila; Microbial Sensitivity Tests; Anti-Bacterial Agents; Fish Diseases
PubMed: 38817412
DOI: 10.12688/f1000research.128819.2 -
Antibiotics (Basel, Switzerland) Mar 2022The emergence of antimicrobial-resistant bacteria is an enormous challenge to public health. and are opportunistic pathogens in fish. They exert tremendous adverse...
The emergence of antimicrobial-resistant bacteria is an enormous challenge to public health. and are opportunistic pathogens in fish. They exert tremendous adverse effects on aquaculture production, owing to their acquired antibiotic resistance. A few Clinical and Laboratory Standards Institute (CLSI) epidemiological cut-off values (ECVs) against spp. are available. We evaluated antimicrobial susceptibility by establishing 8 ECVs using two analytical methods, normalized resistance interpretation and ECOFFinder. We detected antimicrobial resistance genes in two motile spp. isolated from aquatic animals. Results showed that 89.2% of and 75.8% of isolates were non-wild types according to the oxytetracycline ECV and ECV, respectively. The antimicrobial resistance genes included , , , , , , , , , , and . The most common gene in spp. isolates was , followed by . Some strains carried more than one gene, with - and - found in ; however, was not detected in any of the strains. Furthermore, 18.6% of and 24.2% of isolates showed presumptive multidrug-resistant phenotypes. The emergence of multidrug resistance among aquatic aeromonads suggests the spread of drug resistance and difficult to treat bacterial infections.
PubMed: 35326806
DOI: 10.3390/antibiotics11030343 -
Microbiology (Reading, England) Sep 2022Neutrophilic Fe(II) oxidizing bacteria play an important role in biogeochemical processes and have also received attention for multiple technological applications. These...
Neutrophilic Fe(II) oxidizing bacteria play an important role in biogeochemical processes and have also received attention for multiple technological applications. These micro-organisms are thought to couple their metabolism with extracellular electron transfer (EET) while oxidizing Fe(II) as electron donor outside the cell. ES-1 is a freshwater chemolithoautotrophic Fe(II) oxidizing bacterium that is challenging to culture and not yet genetically tractable. Analysis of the ES-1 genome predicts multiple EET pathways, which are proposed to be involved in Fe(II) oxidation, but not yet validated. Here we expressed components of two of the proposed EET pathways, including the Mto and Slit_0867-0870 PCC3 pathways from ES-1 into , an established model EET organism. We demonstrate that combinations of putative inner membrane and periplasmic components from the Mto and Slit_0867-0870 PCC3 pathways partially complemented EET activity in mutants lacking native components. Our results provide evidence for electron transfer functionality and interactions of inner membrane and periplasmic components from the Mto and Slit_0867-0870 PCC3 pathways. Based on these findings, we suggest that EET in ES-1 could be more complicated than previously considered and raises questions regarding directionality of these electron transfer pathways.
Topics: Electron Transport; Electrons; Ferrous Compounds; Oxidation-Reduction; Periplasm
PubMed: 36111788
DOI: 10.1099/mic.0.001240 -
Frontiers in Microbiology 2022species are Gram-negative bacteria that infect various living organisms and are ubiquitously found in different aquatic environments. In this study, we used whole...
species are Gram-negative bacteria that infect various living organisms and are ubiquitously found in different aquatic environments. In this study, we used whole genome sequencing (WGS) to identify and compare the antimicrobial resistance (AMR) genes, integrons, transposases and plasmids found in , and isolated from Indian major carp (, Indian carp (, catfish () and Nile tilapia () sampled in India. To gain a wider comparison, we included 11 whole genome sequences of spp. from different host species in India deposited in the National Center for Biotechnology Information (NCBI). Our findings show that all 15 sequences examined had multiple AMR genes of which the Ambler classes B, C and D β-lactamase genes were the most dominant. The high similarity of AMR genes in the sequences obtained from different host species point to interspecies transmission of AMR genes. Our findings also show that all sequences examined encoded several multidrug efflux-pump proteins. As for genes linked to mobile genetic elements (MBE), only the class I integrase was detected from two fish isolates, while all transposases detected belonged to the insertion sequence (IS) family. Only seven of the 15 sequences examined had plasmids and none of the plasmids encoded AMR genes. In summary, our findings show that spp. isolated from different host species in India carry multiple AMR genes. Thus, we advocate that the control of AMR caused by spp. in India should be based on a One Health approach.
PubMed: 36532495
DOI: 10.3389/fmicb.2022.1008870 -
Biology Nov 2021The genus has been recognised as an important pathogenic species in aquaculture that causes motile septicaemia (MAS) or less severe, chronic infections. This study...
The genus has been recognised as an important pathogenic species in aquaculture that causes motile septicaemia (MAS) or less severe, chronic infections. This study compares the pathogenicity of the different spp. that were previously isolated from freshwater fish with signs of MAS. A total of 124 isolates of spp. were initially screened for the ability to grow on M9 agar with -inositol as a sole carbon source, which is a discriminatory phenotype for the hypervirulent (vAh) pathotype. Subsequently, LD of six selected spp were determined by intraperitoneal injection of bacterial suspension containing 10, 10, and 10 CFU/mL of the respective sp. to red hybrid tilapias. The kidneys, livers and spleens of infected moribund fish were examined for histopathological changes. The screening revealed that only 1P11S3 was able to grow using -inositol as a sole carbon source, and no vAh strains were identified. The LD of 1P11S3 was 10 CFU/mL, while the non--inositol utilizing 4PS2 and 8TK3 was lower at 10 CFU/mL. Similarly, tilapia challenged with the -inositol 1P11S3 showed significantly ( < 0.05) less severe signs, gross and histopathological lesions, and a lower mortality rate than the non--inositol 4PS2 and 8TK3. These findings suggested that -inositol utilizing 1P11S3 was not a hypervirulent sp. under current experimental disease challenge conditions, and that diverse spp. are of concern in aquaculture farmed freshwater fish. Therefore, future study is warranted on genomic level to further elucidate the influence of -inositol utilizing ability on the pathogenesis of spp., since this ability correlates with hypervirulence in strains.
PubMed: 34827185
DOI: 10.3390/biology10111192 -
BMC Microbiology Jan 2021Hypervirulent Aeromonas hydrophila (vAh) is an emerging pathogen in freshwater aquaculture that results in the loss of over 3 million pounds of marketable channel...
BACKGROUND
Hypervirulent Aeromonas hydrophila (vAh) is an emerging pathogen in freshwater aquaculture that results in the loss of over 3 million pounds of marketable channel catfish, Ictalurus punctatus, and channel catfish hybrids (I. punctatus, ♀ x blue catfish, I. furcatus, ♂) each year from freshwater catfish production systems in Alabama, U.S.A. vAh isolates are clonal in nature and are genetically unique from, and significantly more virulent than, traditional A. hydrophila isolates from fish. Even with the increased virulence, natural infections cannot be reproduced in aquaria challenges making it difficult to determine modes of infection and the pathophysiology behind the devastating mortalities that are commonly observed. Despite the intimate connection between environmental adaptation and plastic response, the role of environmental adaption on vAh pathogenicity and virulence has not been previously explored. In this study, secreted proteins of vAh cultured as free-living planktonic cells and within a biofilm were compared to elucidate the role of biofilm growth on virulence.
RESULTS
Functional proteolytic assays found significantly increased degradative activity in biofilm secretomes; in contrast, planktonic secretomes had significantly increased hemolytic activity, suggesting higher toxigenic potential. Intramuscular injection challenges in a channel catfish model showed that in vitro degradative activity translated into in vivo tissue destruction. Identification of secreted proteins by HPLC-MS/MS revealed the presence of many putative virulence proteins under both growth conditions. Biofilm grown vAh produced higher levels of proteolytic enzymes and adhesins, whereas planktonically grown cells secreted higher levels of toxins, porins, and fimbrial proteins.
CONCLUSIONS
This study is the first comparison of the secreted proteomes of vAh when grown in two distinct ecological niches. These data on the adaptive physiological response of vAh based on growth condition increase our understanding of how environmental niche partitioning could affect vAh pathogenicity and virulence. Increased secretion of colonization factors and degradative enzymes during biofilm growth and residency may increase bacterial attachment and host invasiveness, while increased secretion of hemolysins, porins, and other potential toxins under planktonic growth (or after host invasion) could result in increased host mortality. The results of this research underscore the need to use culture methods that more closely mimic natural ecological habitat growth to improve our understanding of vAh pathogenesis.
Topics: Aeromonas hydrophila; Alabama; Animals; Aquaculture; Bacterial Proteins; Bacteriological Techniques; Biofilms; Chromatography, High Pressure Liquid; Fish Diseases; Gram-Negative Bacterial Infections; Ictaluridae; Plankton; Proteomics; Tandem Mass Spectrometry; Virulence; Whole Genome Sequencing
PubMed: 33407117
DOI: 10.1186/s12866-020-02065-2 -
Iranian Journal of Veterinary Research 2022Nile tilapia is a highly valuable fish in the aquaculture sector. A culture farm has reported heavy mortalities of tilapia.
BACKGROUND
Nile tilapia is a highly valuable fish in the aquaculture sector. A culture farm has reported heavy mortalities of tilapia.
AIMS
The present study aimed to identify the etiological agent responsible for the heavy mortality in cage cultured tilapia.
METHODS
The moribund and freshly dead fishes were analyzed for clinical signs. Biochemical and molecular characterizations were performed to identify the etiological agents of the disease. Also, polymerase chain reaction (PCR) assay was used to detect the presence of the virulence genes. The susceptibility of the isolates to various antibiotics was tested by the disk diffusion method.
RESULTS
The results of the biochemical tests and PCR assay confirmed that co-infection with , and was responsible for the disease severity. Phylogenetic analysis of the gene showed that and isolates shared 99% and 98% sequence homology with and previously deposited in the Genbank database. The multiple antibiotic resistance (MAR) index of was 0.16 and that of was 0.71. The PCR test revealed that both pathogens harbored numerous virulence factors. The experimental infection study confirmed that the synergistic action of and led to increased mortality in tilapia. Histopathological changes were observed in the liver and spleen tissues of the co-infected fishes.
CONCLUSION
These findings indicate that the disease outbreak in the tilapia culture farm occurred as a result of co-infection by and .
PubMed: 36425608
DOI: 10.22099/IJVR.2022.41796.6084 -
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