First Detection of AmpC β-Lactamase bla _CMY-2 on a Conjugative IncA/C Plasmid in a Vibrio parahaemolyticus Isolate of Food Origin

Abstract

bVibrio 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 ␤-lactamase gene bla PER-1 was detectable in one strain, V. parahaemolyticus V43, which was resistant to both third-and fourth-generation cephalosporins. Compared to other bla PER-1 -positive V. parahaemolyticus strains reported in our previous studies, strain V43 was found to harbor an ϳ200-kb conjugative plasmid carrying genes that were different from the antimicrobial resistance genes reported from the previous studies. The ␤-lactamase gene bla CMY-2 was detectable for the first time in another V. parahaemolyticus isolate, V4, which was resistant to third-generation cephalosporins. This bla CMY-2 gene was shown to be located in an ϳ150-kb IncA/C-type conjugative plasmid with a genetic structure consisting of traB-traV-traA-ISEcp1-bla CMY-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 extendedspectrum-␤-lactamase (ESBL) and AmpC ␤-lactamase genes via conjugative plasmids can mediate the development of extendedspectrum cephalosporin resistance in V. parahaemolyticus, thereby posing a potential threat to public health. Vibrio parahaemolyticus is a halophilic Gram-negative bacterium and one of the most important seafood-borne pathogens worldwide. It is widely distributed in estuarine-marine environments and seafood products, often causing infections via the consumption of raw or undercooked seafood (1, 2). The most common symptoms of V. parahaemolyticus infections include gastroenteritis, diarrhea, headache, nausea, and vomiting. For children, the elderly, and people with suppressed immune systems, V. parahaemolyticus intestinal infections can be fatal (3). The pathogenicity of V. parahaemolyticus is always associated with the presence of the toxin genes tdh (encoding the thermostable direct hemolysin [TDH]) and its homolog trh (encoding the thermostable direct hemolysin [TDH]-related hemolysin) (4). The U.S. Food and Drug Administration estimates that approximately 4,500 infections occur per year in the United States, and over the past 15 years, outbreaks have been increasing in terms of scale and frequency (3). In recent years, the number of V. parahaemolyticus infecti...

Characterization of an IncA/C Multidrug Resistance Plasmid in Vibrio alginolyticus

“…S2 in the supplemental mate-rial). This 180-kb conjugative plasmid is larger than the ϳ150-kb V. parahaemolyticus plasmid reported in our previous study (3).…”

“…Of the pathogenic Vibrio species, V. alginolyticus is one of the top three causes of infections in humans and is genetically homologous to V. parahaemolyticus (1,2). Resistance to expanded-spectrum cephalosporins and fluoroquinolones has also been reported in V. parahaemolyticus and V. cholerae but not in other Vibrio species such as V. vulnificus and V. alginolyticus (3,4). Here we report (i) the isolation from food products of V. alginolyticus strains that are resistant to expanded-spectrum cephalosporins and (ii) the resistance mechanisms involved.…”

“…The bla CMY-2 gene was contained in a mobile element, ISEcp1-bla CMY-2 -blc-sugE, that has previously been found mainly in members of the family Enterobacteriaceae, may originate from the Citrobacter freundii chromosome, and is transferrable to other bacterial species through ISEcp1-mediated mobilization and conjugative plasmids (12,13). It has also recently been recovered in IncA/C plasmids harbored by Aeromonas salmonicida and Vibrio parahaemolyticus (3,14). In the region upstream of the conserved bla CMY-2 fragment, another conserved MDR region common to the seven plasmids that contained the floR, tet(A/R), strA, strB, and sul2 elements was also detected.…”

LptD is a promising vaccine antigen and potential immunotherapeutic target for protection against Vibrio species infection

“…Currently, antibiotics remain the major measures to control these bacterial infections, both in aquaculture and in clinical treatment. However, the widespread and frequent use of antibiotics has led to the rapid development and spread of antibiotic resistance in Vibrio species45678, which has become a serious threat to public health worldwide. Therefore, it is urgent to develop prevention strategies or alternative treatments to protect against bacterial infections.…”

Genetic and Biochemical Characterization of VMB‐1, a Novel Metallo‐β‐Lactamase Encoded by a Conjugative, Broad‐Host Range IncC Plasmid from Vibrio spp

“…At present, we expect that the bla VMB‐1 gene remains rarely detectable in clinical Enterobacteriaceae isolates as it takes time for transmission of this new antimicrobial resistance gene from the environmental strains to common human pathogens. However, association of the bla VMB‐1 gene with IncC group plasmids implies a high risk of dissemination of such resistance gene as IncC group plasmids have been identified in bacterial strains of various species recovered from both the environment and clinical setting,12,31 with over 200 sequences of IncC plasmids having been reported or deposited in the GenBank since the first report of such plasmid in 2007 13. IncC plasmid was first described among multidrug resistant Aeromonas hydrophila causing disease in cultured fish in the 1970s, when it was combined with IncA plasmids into IncA/C group 32.…”