Hygiene and Zoonoses Department, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt.
Bacteriology, Mycology and Immunology Department, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt.
J Appl Microbiol. 2018 Jun;124(6):1629-1637. doi: 10.1111/jam.13734. Epub 2018 Mar 7.
Aeromonas hydrophila has been isolated from various fish species in Egypt and is known to carry virulence and antimicrobial resistance genes, which pose a risk for public health. The aim of the present study is to report, for the first time, the infection of mullet (Mugil cephalus) with A. hydrophila and to clarify the potential association between antimicrobial resistance and virulence traits encoded in A. hydrophila.
In this study, the occurrence of A. hydrophila in marketed mullet and the antimicrobial resistance phenotypes of these isolates were determined. Aeromonas hydrophila isolates were screened for the presence of virulence and β-lactam resistance genes; the correlation between both gene groups was also investigated. The infection rate of examined mullet with A. hydrophila was 37% (50/135). The highest antimicrobial resistance was detected to cefoxitin (100%), followed by ampicillin (84%), ceftazidime (56%) and cefotaxime (40%). Only 4% of the isolates were resistant to erythromycin; 6% were resistant to both gentamicin and kanamycin with no resistance to ciprofloxacin. Variable frequencies of virulence and β-lactam resistance genes were evident from PCR, where aerA and bla predominated. The study also indicated a general weak positive correlation (R = 0·3) between both virulence and β-lactam resistance genes. Some of the studied virulence genes (e.g. aerA:hlyA and hlyA:ast) were found to correlate positively.
The presence of virulence and resistance genes in A. hydrophila from food sources poses a serious threat to public health. To our knowledge, this is the first report describing the occurrence of A. hydrophila in mullet and highlighting the coexistence of virulence and β-lactam resistance genes encoded by these bacteria.
These data provide insights into the potential association of antimicrobial resistance and virulence genes in A. hydrophila from marketed mullet in Egypt, which could pose threats to humans even if a weak positive correlation exists between both genes.
已从埃及的各种鱼类中分离出嗜水气单胞菌，该菌携带毒力和抗微生物药物耐药基因，对公共健康构成威胁。本研究的目的首次报道了多鳞鱚（Mugil cephalus）感染嗜水气单胞菌，并阐明了该菌携带的抗微生物药物耐药和毒力基因之间的潜在关联。
本研究测定了市售多鳞鱚中嗜水气单胞菌的发生情况和这些分离株的抗微生物药物耐药表型。筛选了嗜水气单胞菌分离株中存在的毒力和β-内酰胺耐药基因；还研究了这两个基因群之间的相关性。受检多鳞鱚的嗜水气单胞菌感染率为 37%（50/135）。对头孢西丁的耐药率最高（100%），其次为氨苄西林（84%）、头孢他啶（56%）和头孢噻肟（40%）。仅 4%的分离株对红霉素耐药；6%的分离株对庆大霉素和卡那霉素耐药，对环丙沙星均敏感。PCR 显示，毒力和β-内酰胺耐药基因的频率各不相同，其中 aerA 和 bla 占优势。研究还表明，两种毒力和β-内酰胺耐药基因之间存在一般较弱的正相关（R=0.3）。一些研究的毒力基因（如 aerA:hlyA 和 hlyA:ast）呈正相关。
食源性病原体嗜水气单胞菌携带毒力和耐药基因对公共健康构成严重威胁。据我们所知，这是首次报道嗜水气单胞菌在多鳞鱚中的存在，并强调了这些细菌携带的毒力和β-内酰胺耐药基因的共存。
这些数据提供了有关埃及市售多鳞鱚中嗜水气单胞菌抗微生物药物耐药和毒力基因潜在关联的见解，即使这两个基因之间存在较弱的正相关，这些基因也可能对人类构成威胁。
