Page 251 - 《水产学报》2026年第2期

2 期 谭美星，等：黄鳝致病菌豚鼠气单胞菌分离鉴定、药敏特性及其生物学分析 50 卷

Isolation, identification, drug sensitivity characteristics and biological
analysis of pathogenic Aeromonas caviae in Monopterus albus

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TAN Meixing , QIN Man , YANG Xiaoyu , LI Huaming , ZOU Chunmei ,
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ZHANG Fuxian , GAO Weihua , ZHAO Chengmin , PENG Mo 4
(1. College of Animal Science and Technology, Yangtze University, Jingzhou 434023, China;
2. Hubei Geshuo Biotechnology Co., Ltd., Jingzhou 434000, China;
3. Hubei Xiaobenyu Agricultural Development Co., Ltd., Jingmen 448200, China;
4. College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang 330045, China)
Abstract: Monopterus albus is renowned for its tender, delectable flesh and exceptional nutritional profile. It is particularly rich
in essential fatty acids like DHA and EPA, and possesses significant medicinal properties, including anti-aging and blood lipid
regulation, alongside considerable economic value.With the growing demand for M. albus, the continuous expansion and
intensification of artificial cultivation, coupled with ongoing changes in the external environment, M. albus is highly suscept-
ible to infections by bacteria, viruses, parasites, and fungi. Diseases caused by bacterial infections have inflicted substantial
losses on M. albus farming. Aeromonas caviae is a common zoonotic pathogen that infects humans, animals, and fish. It is
widely distributed in various aquatic environments and tends to cause infections and multiple complications in hosts with com-
promised immunity. To investigate the pathogenic agents and prevention/control methods for the hemorrhagic symptoms on the
body surface and visceral organs of diseased M. albus in a farming base in Jingzhou City, Hubei Province. In this study, a dom-
inant bacterial strain was isolated from the lesioned tissues of M. albus. Its biological characteristics were systematically ana-
lyzed through morphological observation, physiological and biochemical identification, 16S rRNA gene sequencing, multilocus
sequence typing (MLST) analysis, antimicrobial susceptibility testing, pathogenicity assays, and resistance gene sequencing.
The isolated strain is a Gram-negative short bacillus. 16S rRNA gene sequencing results confirmed that the isolate is A.caviae
derived from M. albus, designated as Ac240602. The isolated strain Ac240602 exhibits β-hemolytic activity, and its molecular
typing is ST 2615. The artificially infected M. albus showed swelling of the skin and anus, as well as varying degrees of hemor-
rhage in the liver, intestines, spleen, and kidneys, which were similar to the symptoms of naturally infected cases. The isolated
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strain harbors 8 virulence genes including lip, alt, and act, with a median lethal dose (LD 50 ) of 1.00×10 CFU/mL for M. albus.
The isolated strain is highly sensitive to 11 drugs including piperacillin, ceftriaxone, and doxycycline, while carrying 17 resist-
ance genes such as blaTEM, aadA1, and aadA2, thus being identified as a multidrug-resistant strain. Strain Ac240602 exhibits
moderate biofilm-forming ability and is an ESBLs (extended-spectrum β-lactamase)-producing positive strain. The carried res-
istance gene blaTEM shares 100% sequence identity with TEM-1 (GenBank accession no.: MT387455.1) and shows close evol-
utionary relationship with TEM-155 and TEM-47. The isolated strain is sensitive to traditional Chinese medicines such as Schis-
andra chinensis, Prunus mume, and Paeonia veitchii. This study provides theoretical basis and data support for the infection
and comprehensive prevention and control of Aeromonas in M. albus.
Key words: Monopterus albus; Aeromonas caviae; isolation and identification; pathogenicity; drug resistance
Corresponding authors: ZHANG Fuxian. E-mail: zhangfuxian99@163.com;
GAO Weihua. E-mail: gwh105@126.com
Funding projects: Hubei Provincial Natural Science Foundation (2022CFB314); Jingzhou Science and Technology Plan
Project (2025CC32)

中国水产学会主办 sponsored by China Society of Fisheries https://www.china-fishery.cn
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