[Objectives]To explore the function of hcp gene in Aeromonas hydrophila.[Methods]A pair of specific primers was designed referring to the hcp gene sequence of A.hydrophila.The hcp gene was amplified by PCR,and performed bioinformatics analysis.[Results]The hcp gene had a total length of 1650 bp and encoded 549 amino acids.The theoretical molecular weight of the protein predicted was about 59476.44 kDa.After predicting the N-terminal signal peptide structure of the amino acid sequence,neither obvious signal peptide cleavage site nor signal peptide was found,and the protein had no transmembrane region.The amino acid sequence had a N-glycosylation site,4 protein kinase C phosphorylation sites,7 casein kinase II phosphorylation sites,9 N-myristoylation sites,4 isoprene binding sites,10 microbody C-terminal target signal sites,and an ATP/GTP binding site motif A(P-ring).The amino acid sequence of hcp gene of A.hydrophila was performed homology analysis with other Aeromonas strains,and it showed higher homology with A.veronii.In the secondary structure,theα-helix,β-sheet,random coil and extended strand accounted for 45.36%,6.01%,37.52%and 11.11%,respectively.The tertiary structure model consisted of 18α-helix and 22β-sheet.Analysis of protein-protein network interaction demonstrated that the proteins interacting with Hcp protein were AHA_3407,nrfA,nirB-1,nirB-2 and AHA_1112.[Conclusions]Through the bioinformatics prediction results,the basic information of hcp gene of A.hydrophila is preliminarily understood,and the possible function of this protein is predicted,in order to provide guidance for subsequent vaccine research.
Fan LIXingjun FUHaiyun FENGShi WANGWeijie ZHANGHuanying PANGNa WANG
The study was conducted to identify Aeromonas spp.and Vibrio spp.from fresh Pangasius fish(n=153)in Cambodia and test their antimicrobial susceptibility to antibiotics.The samples were collected from different wet markets of Phnom Penh city and Kampong Thom,and Siem Reap provinces.The bacteria were isolated by using selective medium and their AMR(Antimicrobial Resistance)profile was tested by API 20E technique,respectively.Susceptibility profile was determined for seven antibiotics commonly used.The Vibrio spp.(34.64%,n=53)was found to be higher than Aeromonas spp.(24.83%,n=38).Four Vibrio and four Aeromonas species were identified where V.parahaemolyticus(57%,n=30)was the highest,followed by V.cholerae(38%,n=20),V.fluvialis(3.8%,n=2)and V.aglinolyticus(1.9%,n=1),whereas A.hydrophila(47%,n=18)was the highest,followed by A.hydrophila/caviae(45%,n=17),A.sobria(5%,n=2),A.caviae(2.6%,n=1).All the species presented high multi-resistance to the tested antibiotics.The antibiotic susceptibility profile to ampicillin(74%-100%),ciprofloxacin(7%-100%),sulfamethoxazole/trimethoprim(14%-100%),florfenicol(14%-100%),oxytetracycline(7%-100%),erythromycin(10%-100%)and colistin sulphate(33%-100%)was revealed resistance level in Aeromonas spp.whereas few species of Vibrio spp.resistant to ampicillin(43%-100%),ciprofloxacin(14%-100%),sulfamethoxazole/trimethoprim(14%-100%),florfenicol(14%-100%),oxytetracycline(20%-100%),erythromycin(29%-100%),colistin sulphate(33%-100%)were also identified.The results revealed these Aeromonas spp.and Vibrio spp.are potentially reservoirs of antibiotic resistance genes.MDR(Multidrug Resistance)was widespread among the samples isolated.That is a high-risk source of contamination since those pathogens and antimicrobials are often used.Our findings highlight that the aquatic environment and fresh Pangasius fish act as reservoirs of AMR Aeromonas spp.and Vibrio spp.which underline the need for a judicious use of antimicrobials and timely surveillance of AMR in aquaculture.Overall,the findings of our stud
