<i>Aeromonas hydrophila</i>, an Emerging Causative Agent of Freshwater-Farmed Whiteleg shrimp <i>Litopenaeus vannamei</i>
<i>Aeromonas hydrophila</i> is a well-known bacterial pathogen associated with mass mortalities in aquaculture. Yet, few reports are available on whiteleg shrimp-pathogenic <i>A. hydrophila</i>. In the present study, a virulent isolate WS05 was confirmed as a causative agent...
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doaj-b213f3306ec842a6862292b835fe2faa2020-11-25T01:25:27ZengMDPI AGMicroorganisms2076-26072019-10-0171045010.3390/microorganisms7100450microorganisms7100450<i>Aeromonas hydrophila</i>, an Emerging Causative Agent of Freshwater-Farmed Whiteleg shrimp <i>Litopenaeus vannamei</i>Huihua Zhou0Chunlei Gai1Guifang Ye2Jian An3Kai Liu4La Xu5Haipeng Cao6National Pathogen Collection Center for Aquatic Animals, Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai 201306, ChinaMarine Biology Institute of Shandong, Qingdao 266104, ChinaNational Pathogen Collection Center for Aquatic Animals, Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai 201306, ChinaLianyungang Marine and Fisheries Development Promotion Center, Lianyungang 222000, ChinaInstitute of Fishery Science, Hangzhou Academy of Agricultural Sciences, Hangzhou 310024, ChinaMarine Biology Institute of Shandong, Qingdao 266104, ChinaNational Pathogen Collection Center for Aquatic Animals, Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai 201306, China<i>Aeromonas hydrophila</i> is a well-known bacterial pathogen associated with mass mortalities in aquaculture. Yet, few reports are available on whiteleg shrimp-pathogenic <i>A. hydrophila</i>. In the present study, a virulent isolate WS05 was confirmed as a causative agent of diseased freshwater-cultured whiteleg shrimp and showed a mean lethal dose (LD<sub>50</sub>) value of 4.8 × 10<sup>4</sup> CFU mL<sup>−1</sup>. It was identified phenotypically and molecularly as an <i>A. hydrophila</i> strain, and exhibited susceptibility to several veterinary antibiotics extensively used in aquaculture, including cotrimoxazole, doxycycline, florfenicol, neomycin, and tetracycline. In view of the strongest inhibition zone of florfenicol against isolate WS05, the synergistic effect of the combinations of florfenicol and herb extracts was further evaluated, and the result indicated that <i>Punica granatum</i> extract was a potential synergist of florfenicol against isolate WS05 and the fractional inhibitory concentration index (FICI) for the florfenicol-<i>P. granatum</i> extract was calculated as 0.31. When combined with 7.81 mg mL<sup>−1</sup> <i>P. granatum</i> extract, the minimum inhibitory concentration (MIC) of florfenicol against isolate WS05 was reduced from 0.50 to 0.03 mg L<sup>−1</sup>, and its activity against isolate WS05 was also enhanced with a significant reduction of ≥3.61 log in cell density after 24 h of treatment compared with that in the single drug treatment. In addition, the protective effect was potentiated by the combination of florfenicol and <i>P. granatum</i> extract, with a cumulative mortality of 36.66% (<i>p</i> < 0.05) and 33.33% (<i>p</i> < 0.05) lower than that in the single treatment with florfenicol and <i>P. granatum</i> extract after the challenge with isolate WS05 for seven days. As far as we know, this is the first study to describe whiteleg shrimp-pathogenic <i>A. hydrophila</i> and suggest <i>P. granatum</i> extract as a potential synergist of florfenicol against the <i>A. hydrophila</i> pathogen.https://www.mdpi.com/2076-2607/7/10/450<i>aeromonas hydrophila</i><i>litopenaeus vannamei</i><i>punica granatum</i>florfenicolsynergist |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Huihua Zhou Chunlei Gai Guifang Ye Jian An Kai Liu La Xu Haipeng Cao |
spellingShingle |
Huihua Zhou Chunlei Gai Guifang Ye Jian An Kai Liu La Xu Haipeng Cao <i>Aeromonas hydrophila</i>, an Emerging Causative Agent of Freshwater-Farmed Whiteleg shrimp <i>Litopenaeus vannamei</i> Microorganisms <i>aeromonas hydrophila</i> <i>litopenaeus vannamei</i> <i>punica granatum</i> florfenicol synergist |
author_facet |
Huihua Zhou Chunlei Gai Guifang Ye Jian An Kai Liu La Xu Haipeng Cao |
author_sort |
Huihua Zhou |
title |
<i>Aeromonas hydrophila</i>, an Emerging Causative Agent of Freshwater-Farmed Whiteleg shrimp <i>Litopenaeus vannamei</i> |
title_short |
<i>Aeromonas hydrophila</i>, an Emerging Causative Agent of Freshwater-Farmed Whiteleg shrimp <i>Litopenaeus vannamei</i> |
title_full |
<i>Aeromonas hydrophila</i>, an Emerging Causative Agent of Freshwater-Farmed Whiteleg shrimp <i>Litopenaeus vannamei</i> |
title_fullStr |
<i>Aeromonas hydrophila</i>, an Emerging Causative Agent of Freshwater-Farmed Whiteleg shrimp <i>Litopenaeus vannamei</i> |
title_full_unstemmed |
<i>Aeromonas hydrophila</i>, an Emerging Causative Agent of Freshwater-Farmed Whiteleg shrimp <i>Litopenaeus vannamei</i> |
title_sort |
<i>aeromonas hydrophila</i>, an emerging causative agent of freshwater-farmed whiteleg shrimp <i>litopenaeus vannamei</i> |
publisher |
MDPI AG |
series |
Microorganisms |
issn |
2076-2607 |
publishDate |
2019-10-01 |
description |
<i>Aeromonas hydrophila</i> is a well-known bacterial pathogen associated with mass mortalities in aquaculture. Yet, few reports are available on whiteleg shrimp-pathogenic <i>A. hydrophila</i>. In the present study, a virulent isolate WS05 was confirmed as a causative agent of diseased freshwater-cultured whiteleg shrimp and showed a mean lethal dose (LD<sub>50</sub>) value of 4.8 × 10<sup>4</sup> CFU mL<sup>−1</sup>. It was identified phenotypically and molecularly as an <i>A. hydrophila</i> strain, and exhibited susceptibility to several veterinary antibiotics extensively used in aquaculture, including cotrimoxazole, doxycycline, florfenicol, neomycin, and tetracycline. In view of the strongest inhibition zone of florfenicol against isolate WS05, the synergistic effect of the combinations of florfenicol and herb extracts was further evaluated, and the result indicated that <i>Punica granatum</i> extract was a potential synergist of florfenicol against isolate WS05 and the fractional inhibitory concentration index (FICI) for the florfenicol-<i>P. granatum</i> extract was calculated as 0.31. When combined with 7.81 mg mL<sup>−1</sup> <i>P. granatum</i> extract, the minimum inhibitory concentration (MIC) of florfenicol against isolate WS05 was reduced from 0.50 to 0.03 mg L<sup>−1</sup>, and its activity against isolate WS05 was also enhanced with a significant reduction of ≥3.61 log in cell density after 24 h of treatment compared with that in the single drug treatment. In addition, the protective effect was potentiated by the combination of florfenicol and <i>P. granatum</i> extract, with a cumulative mortality of 36.66% (<i>p</i> < 0.05) and 33.33% (<i>p</i> < 0.05) lower than that in the single treatment with florfenicol and <i>P. granatum</i> extract after the challenge with isolate WS05 for seven days. As far as we know, this is the first study to describe whiteleg shrimp-pathogenic <i>A. hydrophila</i> and suggest <i>P. granatum</i> extract as a potential synergist of florfenicol against the <i>A. hydrophila</i> pathogen. |
topic |
<i>aeromonas hydrophila</i> <i>litopenaeus vannamei</i> <i>punica granatum</i> florfenicol synergist |
url |
https://www.mdpi.com/2076-2607/7/10/450 |
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