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Journal of Applied Microbiology Sep 2018Antibiotics and several other chemicals have been used to prevent fish diseases. However, this situation results in economic loss for the companies in the aquaculture...
AIMS
Antibiotics and several other chemicals have been used to prevent fish diseases. However, this situation results in economic loss for the companies in the aquaculture industry and most importantly it pollutes the environment. Cinnamic acid is a naturally occurring aromatic acid and is considered to be safe for human consumption. Therefore, in this study, the antibacterial activity of trans-cinnamic acid and commonly used antibiotics, namely chloramphenicol, vancomycin, streptomycin and erythromycin, were tested against 32 bacteria, including fish pathogens, nonpathogenic isolates and collection strains.
METHODS AND RESULTS
Trans-cinnamic acid was applied against the bacteria using the disc diffusion and microdilution method under in vitro conditions. Antibiotics were also tested under similar conditions against all tested bacteria using the disc diffusion method. The results show that among 32 bacterial strains trans-cinnamic acid exhibited potent inhibitory effect on the Gram-negative fish pathogen Aeromonas sobria. In addition, a moderate inhibition of trans-cinnamic acid of fish pathogens Aeromonas salmonicida, Vibrio (Listonella) anguillarum, Vibrio crassostreae and Yersinia ruckeri was also observed for trans-cinnamic acid in our study. On the contrary, the majority of nonpathogenic intestinal isolates were resistant to trans-cinnamic acid.
CONCLUSIONS
To the best of our knowledge, this is the first report on the antimicrobial activity of trans-cinnamic acid on 24 of the studied bacteria isolated from fish. In conclusion, trans-cinnamic acid can be used as an environmentally friendly alternative additive to prevent and control primarily A. sobria, as well as other pathogenic bacteria such as A. salmonicida, V. anguillarum, V. crassostreae and Y. ruckeri.
SIGNIFICANCE AND IMPACT OF THE STUDY
This study indicated that trans-cinnamic acid may present an environmentally friendly alternative therapeutic agent against A. sobria infections in the aquaculture industry.
PubMed: 30179290
DOI: 10.1111/jam.14097 -
International Journal of Molecular... Jul 2018In order to understand the molecular basis underlying the host immune response of koi carp (), Illumina HiSeq 2000 is used to analyze the muscle and spleen transcriptome...
In order to understand the molecular basis underlying the host immune response of koi carp (), Illumina HiSeq 2000 is used to analyze the muscle and spleen transcriptome of koi carp infected with (). assembly of paired-end reads yielded 69,480 unigenes, of which the total length, average length, N50, and GC content are 70,120,028 bp, 1037 bp, 1793 bp, and 45.77%, respectively. Annotation is performed by comparison against various databases, yielding 42,229 (non-redundant protein sequence (NR): 60.78%), 59,255 (non-redundant nucleotide (NT): 85.28%), 35,900 (Swiss-Prot: 51.67%), 11,772 (clusters of orthologous groups (COG): 16.94%), 33,057 (Kyoto Encyclopedia of Genes and Genomes (KEGG): 47.58%), 18,764 (Gene Ontology (GO): 27.01%), and 32,085 (Interpro: 46.18%) unigenes. Comparative analysis of the expression profiles between bacterial challenge fish and control fish identifies 7749 differentially expressed genes (DEGs) from the muscle and 7846 DEGs from the spleen. These DEGs are further categorized with KEGG. Enrichment analysis of the DEGs and unigenes reveals major immune-related functions, including up-regulation of genes related with Toll-like receptor signaling, complement and coagulation cascades, and antigen processing and presentation. The results from RNA-Seq data are also validated and confirmed the consistency of the expression levels of seven immune-related genes after 24 h post infection with qPCR. Microsatellites (11,534), including di-to hexa nucleotide repeat motifs, are also identified. Altogether, this work provides valuable insights into the underlying immune mechanisms elicited during bacterial infection in koi carp that may aid in the future development of disease control measures in protection against .
Topics: Aeromonas; Animals; Carps; Fish Proteins; Gram-Negative Bacterial Infections; Molecular Sequence Annotation; Muscles; Spleen; Transcriptome
PubMed: 30036965
DOI: 10.3390/ijms19072107 -
Frontiers in Microbiology 2017is a mesophilic motile aeromonad currently depicted as an opportunistic pathogen, despite increasing evidence of mutualistic interactions in salmonid fish. However, the...
is a mesophilic motile aeromonad currently depicted as an opportunistic pathogen, despite increasing evidence of mutualistic interactions in salmonid fish. However, the determinants of its host-microbe associations, either mutualistic or pathogenic, remain less understood than for other aeromonad species. On one side, there is an over-representation of pathogenic interactions in the literature, of which only three articles to date report mutualistic interactions; on the other side, genomic characterization of this species is still fairly incomplete as only two draft genomes were published prior to the present work. Consequently, no study specifically investigated the biodiversity of . In fact, the investigation of as a species complex may have been clouded by: (i) confusion with biovar because of their similar biochemical profiles, and (ii) the intrinsic low resolution of previous studies based on 16S rRNA gene sequences and multilocus sequence typing. So far, the only high-resolution, phylogenomic studies of the genus included one strain (CECT 4245 / Popoff 208), making it impossible to robustly conclude on the phylogenetic intra-species diversity and the positioning among other species. To further understand the biodiversity and the spectrum of host-microbe interactions in as well as its potential genomic diversity, we assessed the genomic and phenotypic heterogeneity among five strains: two clinical isolates recovered from infected fish (JF2635 and CECT 4245), one from an infected amphibian (08005) and two recently isolated brook charr probionts (TM12 and TM18) which inhibit growth of subsp. (a salmonid fish pathogen). A phylogenomic assessment including 2,154 softcore genes corresponding to 946,687 variable sites from 33 genomes confirms the status of as a distinct species divided in two subclades, with 100% bootstrap support. The phylogenomic split of in two subclades is corroborated by a deep dichotomy between all five strains in terms of inhibitory effect against subsp. , gene contents and codon usage. Finally, the antagonistic effect of strains TM12 and TM18 suggests novel control methods against subsp. .
PubMed: 29276504
DOI: 10.3389/fmicb.2017.02434 -
PloS One 2017Aeromonas sobria serine protease (ASP) is an extracellular serine protease secreted by the organism. Here, we identified the amino acid residue of ASP that contributes...
Aeromonas sobria serine protease (ASP) is an extracellular serine protease secreted by the organism. Here, we identified the amino acid residue of ASP that contributes to substrate specificity by using both synthetic peptides and biological protein components. The results showed that the arginine residue at position 566 (Arg-566) of ASP, which is located in the extra occluding region of ASP close to an entrance of the catalytic cavity, is involved in the substrate specificity. A substitutional point mutation of the Arg-566 residue of ASP to Ala residue (ASP[R566A]) caused a decrease of the proteolytic efficiency for a certain substrate. In addition, ASP lost the ability to recognize the primary substrate by such a point mutation, and ASP[R566A] reacted to a wide range of synthetic substrates. It is likely that Arg-566 causes an interaction with the amino acid residue at position P3 of the substrate, which is the third amino acid residue upstream from the cleavage site. Another study using ORF2 protein, a chaperone protein of ASP, further suggested that Arg-566 could also play an important role in interaction with ORF2. We therefore conclude that the Arg-566 residue of ASP is likely responsible for the selection of substrates.
Topics: Aeromonas; Amino Acid Sequence; Arginine; Bacterial Proteins; Fibrinogen; Humans; Kininogens; Molecular Chaperones; Mutagenesis, Site-Directed; Proteolysis; Serine Proteases; Substrate Specificity
PubMed: 29023605
DOI: 10.1371/journal.pone.0186392 -
Secondary bacterial infections and antibiotic resistance among tungiasis patients in Western, Kenya.PLoS Neglected Tropical Diseases Sep 2017Tungiasis or jigger infestation is a parasitic disease caused by the female sand flea Tunga penetrans. Secondary infection of the lesions caused by this flea is common...
Tungiasis or jigger infestation is a parasitic disease caused by the female sand flea Tunga penetrans. Secondary infection of the lesions caused by this flea is common in endemic communities. This study sought to shed light on the bacterial pathogens causing secondary infections in tungiasis lesions and their susceptibility profiles to commonly prescribed antibiotics. Participants were recruited with the help of Community Health Workers. Swabs were taken from lesions which showed signs of secondary infection. Identification of suspected bacteria colonies was done by colony morphology, Gram staining, and biochemical tests. The Kirby Bauer disc diffusion test was used to determine the drug susceptibility profiles. Out of 37 participants, from whom swabs were collected, specimen were positive in 29 and 8 had no growth. From these, 10 different strains of bacteria were isolated. Two were Gram positive bacteria and they were, Staphylococcus epidermidis (38.3%) and Staphylococcus aureus (21.3%). Eight were Gram negative namely Enterobacter cloacae (8.5%), Proteus species (8.5%), Klebsiellla species (6.4%), Aeromonas sobria (4.3%), Citrobacter species (4.3%), Proteus mirabillis(4.3%), Enterobacter amnigenus (2.1%) and Klebsiella pneumoniae (2.1%). The methicillin resistant S. aureus (MRSA) isolated were also resistant to clindamycin, kanamycin, erythromycin, nalidixic acid, trimethorprim sulfamethoxazole and tetracycline. All the Gram negative and Gram positive bacteria isolates were sensitive to gentamicin and norfloxacin drugs. Results from this study confirms the presence of resistant bacteria in tungiasis lesions hence highlighting the significance of secondary infection of the lesions in endemic communties. This therefore suggests that antimicrobial susceptibility testing may be considered to guide in identification of appropriate antibiotics and treatment therapy among tungiasis patients.
Topics: Adolescent; Adult; Aged; Animals; Anti-Bacterial Agents; Bacterial Infections; Child; Child, Preschool; Coinfection; Drug Resistance, Multiple, Bacterial; Female; Gram-Negative Bacteria; Gram-Positive Bacteria; Humans; Kenya; Male; Microbial Sensitivity Tests; Middle Aged; Tungiasis; Young Adult
PubMed: 28886013
DOI: 10.1371/journal.pntd.0005901 -
Scientific Reports Aug 2017Aeromonas sobria is opportunistic pathogen frequently found in environment and food. Interfering with its quorum sensing (QS) system could be a promising way to...
Aeromonas sobria is opportunistic pathogen frequently found in environment and food. Interfering with its quorum sensing (QS) system could be a promising way to alleviate its virulence. In this study, curcumin liposomes were prepared and their characteristics like particle size, zeta potential, PDI (Polymey Disperse Index), encapsulation efficiency and loading capacity were measured. The quorum sensing inhibitory effect of curcumin liposomes under sub-MIC (Minimum Inhibitory Concentration) on siderophore production, swimming and swarming motility, extracellular proteases, biofilm formation and AHLs (N-acylhomoserine lactones) production of A. sobria were also determined. The results showed that, the curcumin liposomes with high encapsulation capacity (84.51 ± 0.58%) were stable and homogeneous. QS-regulated phenotypes of the pathogen were significantly inhibited by curcumin liposomes. The in silico analysis revealed that the QS system of A. sobria may be inhibited by released curcumin from curcumin liposomes through interacting with the built LuxI type protein and blocking the production of AHLs.
Topics: Acyl-Butyrolactones; Aeromonas; Amino Acid Sequence; Bacterial Proteins; Biofilms; Curcumin; Liposomes; Microbial Sensitivity Tests; Microscopy, Electron, Scanning; Molecular Docking Simulation; Particle Size; Protein Binding; Protein Conformation; Quorum Sensing; Sequence Homology, Amino Acid
PubMed: 28819178
DOI: 10.1038/s41598-017-08986-9 -
BMJ Case Reports Mar 2017
Topics: Abscess; Administration, Intravenous; Adolescent; Aeromonas; Drainage; Ethmoid Sinusitis; Exophthalmos; Gram-Negative Bacterial Infections; Humans; Male; Ophthalmic Solutions; Orbital Diseases; Rivers; Tomography, X-Ray Computed; Treatment Outcome
PubMed: 28343158
DOI: 10.1136/bcr-2017-219505 -
Veterinary World Jan 2017This study was conducted to evaluate the presence of spp. in raw and ready-to-eat (RTE) fish commonly consumed in Assiut city, Egypt, and to determine virulence factors...
AIM
This study was conducted to evaluate the presence of spp. in raw and ready-to-eat (RTE) fish commonly consumed in Assiut city, Egypt, and to determine virulence factors due to they play a key role in their pathogenicity.
MATERIALS AND METHODS
A total of 125 samples of raw and RTE fish samples were taken from different fish markets and fish restaurants in Assiut Governorate and screened for the presence of spp. by enrichment on tryptic soy broth then incubated at 30°C for 24 h. Plating unto the sterile Petri dishes containing agar base to which selective supplement was added. The plates were incubated at 37°C for 24 h. Presumptive colonies were biochemically confirmed and analyzed for pathogenicity by hemolysin production, protease, and lipase detection.
RESULTS
The results indicated that raw fish were contaminated with spp. (40% in wild and 36% in cultured Nile tilapia). Regarding RTE, spp. could be isolated with the percentage of 16%, 28% and 20% in fried Bolti, grilled Bolti and fried Bayad, respectively. Out of 35 isolates obtained, 22 were categorized as , 12 were classified as and were found in only one isolate. The virulence factors of spp. were detected and the results showed that all isolates produced of hemolysin (91.4%), protease (77.1%), and lipase enzyme (17.1%).
CONCLUSION
This study indicates that the presence of with virulence potential in fresh and RTE fish may be a major threat to public health.
PubMed: 28246446
DOI: 10.14202/vetworld.2017.34-37 -
Genome Announcements Jan 2017Aeromonas sobria is a Gram-negative, rod-shaped, and ubiquitous bacterium. We present here the draft genome sequence of A. sobria strain 08005, isolated from an...
Aeromonas sobria is a Gram-negative, rod-shaped, and ubiquitous bacterium. We present here the draft genome sequence of A. sobria strain 08005, isolated from an infected bullfrog. It is composed of 66 contigs totaling 4,678,951 bp, contains 4,252 coding DNA sequences (CDSs), four rRNAs, and 88 tRNA sequences, and shows the presence of various putative virulence-related genes.
PubMed: 28082483
DOI: 10.1128/genomeA.01352-16 -
Sensors (Basel, Switzerland) Jul 2016One quorum sensing strain was isolated from spoiled turbot. The species was determined by 16S rRNA gene analysis and classical tests, named Aeromonas sobria AS7....
One quorum sensing strain was isolated from spoiled turbot. The species was determined by 16S rRNA gene analysis and classical tests, named Aeromonas sobria AS7. Quorum-sensing (QS) signals (N-acyl homoserine lactones (AHLs)) were detected by report strains and their structures were further determined by GC-MS. The activity changes of AHLs on strain growth stage as well as the influence of different culture conditions on secretion activity of AHLs were studied by the punch method. The result indicated that strain AS7 could induce report strains to produce typical phenotypic response. N-butanoyl-dl-homoserine lactone (C₄-HSL), N-hexanoyl-dl-homoserine lactone (C₆-HSL), N-octanoyl-dl-homoserine lactone (C₈-HSL), N-decanoyl-dl-homoserine lactone (C10-HSL), N-dodecanoyl-dl-homoserine lactone (C12-HSL) could be detected. The activities of AHLs were density-dependent and the max secretion level was at pH 8, sucrose culture, 1% NaCl and 32 h, respectively. The production of siderophore in strain AS7 was regulated by exogenous C₈-HSL, rather than C₆-HSL. Exogenous C₄-HSL and C₈-HSL accelerated the growth rate and population density of AS7 in turbot samples under refrigerated storage. However, according to the total viable counts and total volatile basic nitrogen (TVB-N) values of the fish samples, exogenous C₆-HSL did not cause spoilage of the turbot fillets. In conclusion, our results suggested that QS was involved in the spoilage of refrigerated turbot.
Topics: 4-Butyrolactone; Acyl-Butyrolactones; Aeromonas; Animals; Flatfishes; Gas Chromatography-Mass Spectrometry; Homoserine; Lactones; Quorum Sensing; RNA, Ribosomal, 16S
PubMed: 27420072
DOI: 10.3390/s16071083