11 4 2 1 5 8 South China Fisheries Science Vol. 11, No. 4 Aug., 215 doi: 1. 3969/ j. issn. 295-78. 215. 4. 11 1, 2 1,, 1 1 1 1,,, ( 1.,, 513; 2., 2136) : 211 ( Plectropomus leopardus),, 1 X11YD5,, 3. 8 g ( Epinephelus coioides) ( LD 5 ) 1. 67 1 5 cfu g - 1, 16S rdna toxr rpod mreb topa rctb 6,, X11YD5 ( Vibrio harveyi), X11YD5 16 5 : ; ; ; 16S rdna : S 941. 4 : A : 295-78 - ( 215) 4-71 - 1 Identification and drug sensitive test of bacterial Pathogens from Plectropomus leopardus with tail fester disease GU Liangbin 1, 2, XU Liwen 1, FENG Juan 1, SU YouLu 1, LIU Guangfeng 1, GUO Zhixun 1 ( 1. Key Lab. of South China Sea Fishery Resource Exploitation & Utilization, Ministry of Agriculture; South China Sea Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou 513, China; 2. College of Fisheries and Life Sciences of Shanghai Ocean University, Shanghai 2136, China) Abstract: In 211, there was an outbreak in a Plectropomus leopardus farm in Wenhui Town, Yandui Village, Hainan Province. The color of sick fish turned white and the tail fin festered. We isolated a Strain X11YD5 from sick P. leopardus which was proved to be pathogen by artificial infection and the LD 5 was 1. 67 1 5 cfu g - 1 in Epinephelus coioides using Karber method. To determine the molecular characteristics of X11YD5, we amplified the 16S rdna, transmembrane regulatory protein ( toxr), RNA polymerase 7 factor ( rpod), actin-like cytoskeleton protein ( mreb), topoisomerase ( topa) and replication origin-binding protein ( rctb) by PCR. Sequence analysis indicates that X11YD5 belonged to V. harveyi. Drug sensitivity test shows that X11YD5 was sensitive to norfloxacin, ofloxacin, ciprofloxacin, enrofloxacin and cotrimoxazole. Key words: Plectropomus leopardus; Vibrio harveyi; tail fester disease; 16S rdna [ 1 ] ( Plectropomus leopardus),,,,,, : 214-1-1; : 214-12 -22 : ( 312227) ; ( 214KX64 ) ; ( 215XH3) : ( 1989 - ),,, E-mail: guliangbin212@ 163. com : ( 1973 - ),,, E-mail: jannyfeng@ 163. com
72 11 [ 2],,, 29 [ 3-5 ],,,, [ 6],,,, 1 [ 7-8] 211, Fig. 1 Diseased P. leopardus,, TCBS ( 1), VP 1, X11YD5, 43, API,, ( 32E), 1. 4. 2 16S rdna mreb rctb rpod topa toxr X11YD5 16 DNA: 5 1 L, 1 1. 1 (, PCR PCR 3. 8 g, 11. 4 cm), 1 2 [ 1 ] 5 L PCR 1%, 7 d 1. 2 ( ), ( ) ) TCBS 1. 4. 3 ( K-B ) [ 11 ], 28 NCCL, 1 L (, 1 8 cfu ml - 1 ) MHA, 1 min 1. 3. 8 m 1. 2 m, 1, 4, 1, 3, 15, 2 X11YD5 2216E 12 16 h,, X11YD5 1 4,. 2, ml,,,,,,, 7 1 X-1 X11YD5 d 1. 4-8 15 2 min, ( ) 1 15 min, 3 5 min, 12 r min - 1 3 5 min,, 13 V, 25 min PCR ( [ 9 ] 1. 4. 1, 1 5 cfu g - 1, 28 24 h, 2. 1 3, ( LD 5 ) 1. 67
4 : 73 1 Tab. 1 Information of primers gene locus protein products primer ( 5 3 ) primer sequence PCR / bp PCR product / annealing temperature 16S rdna - 8F AGAGTTTGATCCTGGCTCAG 1 5 48 1492R GGTTACCTTGTTACGACTT rctb ATGCCNGARGGYTTYAARAG 544 58 rctb-r GTWGGMGCCATRTTRCGYTT toxr toxr-f GAAGCAGCACTCACCGAT 382 55 toxr-r GGTGAAGACTCATCAGCA topa topa-f GAGATCATCGGTGGTGATG 8 63 topa-r GAAGGACGAACGCTTCGTG mreb mreb-f ACTTCGTGGCATGTTTTC 1 59 mreb-r CCGTGCATATCGATCATTTC rpod RNA 7 rpod-f ACGACTGACCCGGTACGCATGT 78 5 AYATGMGNGARATGGGNACNGT rpod-r ATAGAAATAACCAGACGTAAGT TNGCYTCNACCATYTCYTTYT 2 PCR Tab. 2 System and reaction condition of PCR amplification PCR PCR system PCR revolving parameter reactant / L volume step / temperature time number of cycle Premix Taq 25 1 94 4 min 1 template 1 5 2 94 1 min 35 upstream primer 2 3 5 6 45 6 s 35 downstream primer 2 4 72 1 min 35 sterilized distilled water 5 5 72 1 min 1 3 X11YD5 Tab. 3 Pathogenicity of Strain X11YD5 to E. coioides / cfu ml - 1 / ml / / / % group bacterial concentration dosage individual number death number mortality 1 2. 1 1 7. 2 27 27 1 2 2. 1 1 6. 2 27 3 11 3 2. 1 1 5. 2 27 4 2. 1 1 4. 2 27 control. 9%. 2 21 2. 2 X-1 2, TCBS,,,, X-1, ( 2), X11YD5 O/129( 1 g - 1 ), O/129 ( 15 g
74 11 2 X11YD5 ( 1 ) Fig. 2 Gram-staining of Strain X11YD5-1 ) ; ( Na + ), 3% ( NaCl) 6% NaCl, 8% NaCl 1% NaCl ; Fig. 3 Antibiotic resistance of X11YD5 to Gentamicin, 28 35, 4 15 42 ONPG,, VP,,, [ 7, 9 ] X11YD5 X-1 4 2. 3 16 ( 3), X-1 X11YD5, 5, B G 11 2 ( 5) 2. 4 16S rdna mreb rctb toxr topa rpod X11YD5 6 ( 4, 16S rdna KM657348) ( Lateolabrax Japonicus) [ 1 2] ( Rachycentron canadum) [ 13 ] ( http: blast. st-va. ncbi. nlm. nih. gov/blast. cgi), X11YD5 6 ( Penaeus chinensis) [ 1 4] ( Meretrix meretrix) [ 15 ] ( E. awoara) [ 16],, MEGA 6. NJ ( 5 1) ( Babylonia areolata) [ 17-18 ] 6, [ 1 9] ( V. harveyi) 3 4 3 K-B X11YD5 ( ) ( ) ( ) ( ) Cefixime, Furazolidone and Enrofloxacin with K-B method X11YD5 rpod toxr PCR Fig. 4 Agarose electrophoresis of rpod, toxr PCR products of Strain X11YD5, [ 7, 18],,, [ 2 ],
4 : 75 4 X11YD5 Tab. 4 Comparison of main physiological and chemical characteristics of Stain X11YD5, X-1 and V. harveyi detection item detection result X11YD5 X-1 V. harveyi Gram staining - - - TCBS TCBS grow G G Y / G O/129( 15 g) + + + O/129( 1 g) - - - not NaCl tryptone broth - - - 3% NaCl 3% NaCl tryptone broth + + + 6% NaCl 6% NaCl tryptone broth + + + 8% NaCl 8% NaCl tryptone broth - - + 1% NaCl 1% NaCl tryptone broth - - - 4 4 grow - - - 15 15 grow - - - 28 28 grow + + + 35 35 grow + + + 42 42 grow - - - ONPG ONPG reaction - - - catalase + + + oxidase + + + nitrate reduction - - + VP VP reaction - - - methyl red - - + heteroauxing - - - hydrogen sulfide - - - arginine hydrolase - - - arginine decarboxylase - - - iysine decarboxylase + + + ornithine decarboxylase - - ND glucose aerosis - - - arabinose - - - inosite - - ND mannitol - - + raffinose - - ND rhamnose - - D sucrose - - D lactose - - - salicin - - - sorbitol - - ND melibiose - - - carbamide - - ND glucose + + + maltose - - D gelatin + + + : +. ; -. ; D., ; ND. Note: +. positive; -. negative; D. sometimes positive, sometimes negative; ND. no data
76 11 5 X11YD5 X-1 Tab. 5 Antibacterial activity of pathogen X11YD5 and X-1 to different antimicrobial agents chemical B Polymyxin B Kanamycin Ofloxacin dose X11YD5 X-1 / mm /mm diameter susceptibility diameter 25 g - 1 8 R 8 R 3 g - 1 12 R 7 R 5 g - 1 26 S 22 S susceptibility G Penicillin G 1 U R R Gentamicin Tetracycline Furazolidone Norfloxacin Amoxicillin Rifampicin Cotrimoxazole Erythrocin Ciprofloxacin Chloramphenicol Cefixime Enrofloxacin 1 g - 1 16 R 13 R 3 g - 1 14 R 14 R 3 g - 1 13 R 12 R 1 g - 1 35 S 37 S 1 g - 1 R 13 R 5 g - 1 R R 1. 25 g - 1 24 S 23 S 15 g - 1 18 R 19 R 5 g - 1 36 S 26 S 3 g - 1 9 R R 5 g - 1 12 R 17 R 5 g - 1 28 S 37 S : R. ; S. Note: R. resistance; S. sensitivity 5 X11YD5 16S rdna Fig. 5 Dendrogram of 16S rdna sequence analysis of X11YD5
4 : 77 Fig. 6 6 X11YD5 mreb Dendrogram of mreb sequence analysis of X11YD5 Fig. 7 7 X11YD5 rctb Dendrogram of rctb sequence analysis of X11YD5
78 11 Fig. 8 8 X11YD5 rpod Dendrogram of rpod sequence analysis of X11YD5 Fig. 9 9 X11YD5 topa Dendrogram of topa sequence analysis of X11YD5
4 : 79 Fig. 1 1 X11YD5 toxr Dendrogram of toxr sequence analysis of X11YD5 ( V. harveyi) MLSA, 1 X11YD5, ( actin-like cytoskeleton protein, mreb),, ( replication origin-binding protein, X-1 rctb) RNA 7 ( RNA polymerase 7 X11YD5, factor, rpod) ( topoisomerase, topa) X11YD5 ( transmembrane regulatory protein, [ 21-22, 27-28 ] 16S rdna toxr) 5, [ 21-2 2] 16S rdna 16S rd-, NA,, 16S rdna ( V. campnellii ) V. communis 5 ( V. owensii), 3 ( Harveyi,, clade), ( V. rotiferianus) ( V. mytili) ( V. natriegens) rdna, 1% [ 2 4-2 5], 16S rdna BLAST VP, X11YD5 16S rdna, 99%, 16S rdna ( multi-locus se- 16, X11YD5 quence analysis, 97%, API ( 32E),, [ 23] 11, 16S, X11YD5 MLSA) 4 [ 1, 26],,
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