Li Ruichao, Lin Dachuan, Chen Kaichao, Wong Marcus Ho Yin, Chen Sheng
Shenzhen Key Lab for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong PolyU Shenzhen Research Institute, Shenzhen, People's Republic of China State Key Lab of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Shenzhen Key Lab for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong PolyU Shenzhen Research Institute, Shenzhen, People's Republic of China State Key Lab of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
Antimicrob Agents Chemother. 2015 Jul;59(7):4106-11. doi: 10.1128/AAC.05008-14. Epub 2015 Apr 27.
Vibrio parahaemolyticus is an important causative agent of gastroenteritis, with the consumption of contaminated seafood being the major transmission route. Resistance to penicillin is common among V. parahaemolyticus strains, whereas cephalosporin resistance remains rare. In an attempt to assess the current prevalence and characteristics of antibiotic resistance of this pathogen in common food samples, a total of 54 (17% of the total samples) V. parahaemolyticus strains were isolated from 318 meat and seafood samples purchased from supermarkets and wet markets in Shenzhen, China, in 2013. These isolates exhibited high-level resistance to ampicillin, yet they were mostly susceptible to other antimicrobials, except for two that were resistant to extended-spectrum cephalosporins. The β-lactamase gene blaPER-1 was detectable in one strain, V. parahaemolyticus V43, which was resistant to both third- and fourth-generation cephalosporins. Compared to other blaPER-1-positive V. parahaemolyticus strains reported in our previous studies, strain V43 was found to harbor an ∼200-kb conjugative plasmid carrying genes that were different from the antimicrobial resistance genes reported from the previous studies. The β-lactamase gene blaCMY-2 was detectable for the first time in another V. parahaemolyticus isolate, V4, which was resistant to third-generation cephalosporins. This blaCMY-2 gene was shown to be located in an ∼150-kb IncA/C-type conjugative plasmid with a genetic structure consisting of traB-traV-traA-ISEcp1-blaCMY-2-blc-sugE-encR-orf1-orf2-orf3-orf4-dsbC-traC, which is identical to that of other IncA/C conjugative plasmids in Enterobacteriaceae, albeit with a different size. These findings indicate that the transmission of extended-spectrum-β-lactamase (ESBL) and AmpC β-lactamase genes via conjugative plasmids can mediate the development of extended-spectrum cephalosporin resistance in V. parahaemolyticus, thereby posing a potential threat to public health.
副溶血性弧菌是肠胃炎的重要病原体，食用受污染的海鲜是主要传播途径。副溶血性弧菌菌株对青霉素耐药很常见，而对头孢菌素耐药仍很罕见。为评估该病原体在常见食品样本中抗生素耐药性的当前流行情况和特征，2013年从中国深圳超市和湿货市场购买的318份肉类和海鲜样本中，共分离出54株（占总样本的17%）副溶血性弧菌菌株。这些分离株对氨苄西林表现出高水平耐药，但除两株对超广谱头孢菌素耐药外，它们大多对其他抗菌药物敏感。在一株对第三代和第四代头孢菌素均耐药的副溶血性弧菌V43菌株中可检测到β-内酰胺酶基因blaPER-1。与我们之前研究中报道的其他blaPER-1阳性副溶血性弧菌菌株相比，发现V43菌株携带一个约200 kb的接合质粒，其携带的基因与之前研究报道的抗菌耐药基因不同。在另一株对第三代头孢菌素耐药的副溶血性弧菌分离株V4中首次检测到β-内酰胺酶基因blaCMY-2。该blaCMY-2基因位于一个约150 kb的IncA/C型接合质粒中，其遗传结构为traB-traV-traA-ISEcp1-blaCMY-2-blc-sugE-encR-orf1-orf2-orf3-orf4-dsbC-traC，与肠杆菌科其他IncA/C接合质粒相同，只是大小不同。这些发现表明，超广谱β-内酰胺酶（ESBL）和AmpCβ-内酰胺酶基因通过接合质粒的传播可介导副溶血性弧菌对超广谱头孢菌素耐药性的产生，从而对公众健康构成潜在威胁。
