Antimicrobial resistance gene found in marine pathogen

September 20, 2016, American Society for Microbiology

A team of Chinese investigators has discovered a gene for resistance to β-lactamase antibiotics, in the pathogenic marine bacterium, Vibrio parahaemolyticus. The β-lactamase gene, blaVEB-2, has never before been found in V. parahaemolyticus, and in fact, has been found almost exclusively in non-marine pathogens. The research is published Monday, September 19, 2016 in Antimicrobial Agents and Chemotherapy, a journal of the American Society for Microbiology.

The were contained within a novel, highly unusual plasmid. Plasmids are pieces of independent DNA that can jump from one species of bacteria to another, and which frequently carry multiple resistance genes—as this plasmid did. The authors suspect that these plasmids may be enabling Vibrios, and likely other marine bacterial pathogens, to spread resistance—which they note has been gradually climbing among marine pathogens.

"Interestingly, we found that this plasmid can be transferred back to E. coli through a process called conjugation," said corresponding author Sheng Chen, PhD, Associate Professor in Microbiology, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University. "Such plasmid may serve as machinery to collect resistance genes from the environment, and transfer them to other marine organisms, or even other bacteria."

"The results suggest that the Vibrios can readily acquire various types of resistance genes presumably through horizontal gene transfer from other organisms in the marine environment," said Chen. "This may be the reason why there has been a gradual increase in resistance rate among the marine pathogens such as V. parahaemolyticus, which is a common causative agent of food-borne infections but has until recently remained susceptible to most ."

The motivation for the research was Chen's interest in studying the transmission kinetics and host specificity of various mobile resistance elements, notably plasmids, that are responsible for causing an increase in in major bacterial pathogens. Researchers had thought that there was little selection pressure for resistance in the oceans, because antibiotics are thought to be absent from the oceans, "despite the fact that antibiotics may be released into the sea via the sewage system," Chen said. Furthermore, gastroenteritis caused by V. parahaemolyticus is generally self-limiting, so that most cases do not require antibiotic treatment, further reducing selection pressure.

β-lactamases are enzymes that disable β-lactam antibiotics. The penicillin and cephalosporin β-lactams are among the most commonly used antibiotics, and thus, β-lactamases are significant threats to the antibiotic armory.

Explore further: Antibiotic resistance persists in bacteria, even absent selection pressure from antibiotics

More information: Ruichao Li et al. Genetic Characterization of a-carrying plasmid in, Antimicrobial Agents and Chemotherapy (2016). DOI: 10.1128/AAC.01749-16

Related Stories

Antibiotic resistance—it's a social thing

March 15, 2016

Trace concentrations of antibiotic, such as those found in sewage outfalls, are enough to enable bacteria to keep antibiotic resistance, new research from the University of York has found. The concentrations are much lower ...

Mcr-1 gene isolated from human for the first time in Brazil

August 8, 2016

August 8, 2016 - For the first time in Brazil, a particular antibiotic resistance mechanism conferring resistance to the important antibiotic, colistin, has been detected in a human. It was in a strain of Escherichia coli ...

Recommended for you

Apple pivot led by star-packed video service

March 25, 2019

With Hollywood stars galore, Apple unveiled its streaming video plans Monday along with news and game subscription offerings as part of an effort to shift its focus to digital content and services to break free of its reliance ...

How tree diversity regulates invading forest pests

March 25, 2019

A national-scale study of U.S. forests found strong relationships between the diversity of native tree species and the number of nonnative pests that pose economic and ecological threats to the nation's forests.

Scientists solve mystery shrouding oldest animal fossils

March 25, 2019

Scientists from The Australian National University (ANU) have discovered that 558 million-year-old Dickinsonia fossils do not reveal all of the features of the earliest known animals, which potentially had mouths and guts.

Earth's deep mantle flows dynamically

March 25, 2019

As ancient ocean floors plunge over 1,000 km into the Earth's deep interior, they cause hot rock in the lower mantle to flow much more dynamically than previously thought, finds a new UCL-led study.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.