A team of clinician researchers has discovered a highly virulent, multidrug resistant form of the pathogen, Pseudomonas aeruginosa, in patient samples in Ohio. Their investigation suggests that the particular genetic element involved, which is still rare in the United States, has been spreading heretofore unnoticed, and that surveillance is urgently needed. The research is published ahead of print in Antimicrobial Agents and Chemotherapy.
The P. aeruginosa contained a gene for a drug resistant enzyme called a metallo beta-lactamase. Beta-lactamases enable broad-spectrum resistance to beta-lactam antibiotics, including carbapenems, cephalosporins, and penicillins, because they can break the four atom beta-lactam ring, a critical component of these antibiotics' structure.
The initial isolate of metallo-beta-lactamase-producing P. aeruginosa was identified in March, 2012, in a foot wound of a 69-year-old man with type 2 diabetes living in a long-term care facility. During 2012-2013, the investigators identified this highly antibiotic-resistant infection in six other patients. One of the seven patients subsequently died of the infection.
The cases are linked epidemiologically via admission to a community hospital and residence in long-term care facilities in Northeast Ohio. The one exception was a patient from Qatar who was transferred into a tertiary medical center in Ohio, says lead author Federico Perez, of the Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA.
The investigators subsequently found that the metallo beta-lactamase was contained within an integron, a genetic element that can jump from one species of bacterium to another, can reside on plasmids or within the chromosomes, and is known for being able to contain multiple antibiotic resistance genes.
This particular metallo beta-lactamase, verona integron-encoded metallo beta-lactamse (VIM), is widespread globally, if not in the US. "VIM enzymes confer resistance to imipenem and all other beta-lactams," says Perez. "They are not inhibited by metallo beta-lactamase inhibitors."
"Alarmingly, the [extensively drug-resistant] phenotype expressed by some of these isolates precluded any reliable antibiotic treatment since they even displayed intermediate resistance to colistin, an 'agent of last resort'," the researchers write. "Patients who were affected had multiple comorbidities, endured prolonged colonization, required long-term care and, in one instance had a lethal outcome from a bloodstream infection."
On top of everything else, genomic sequencing and assembly showed that the integron was part of a novel 35 kilobase region that included a transposon (another mobile genetic element) and the so-called Salmonella Genomic Island 2 (SGI2). That indicated that a recombination event had occurred between Salmonella and P. aeruginosa, contributing even more resistance genes to the latter.
"This is the first description of genetic exchange of a large mobile element—the Salmonella Genome Island—and resistance genes between P. aerugenosa and Salmonella, says Perez. "This movement of genetic material creates concern that metallo beta-lactamases will disseminate rapidly in these enteric pathogens that are also very invasive. We are also concerned about the possibility of enhanced virulence."
The manuscript can be found online at http://bit.ly/asmtip0814a. The final version of the article is scheduled for the October 2014 issue of Antimicrobial Agents and Chemotherapy.
Antimicrobial Agents and Chemotherapy is a publication of the American Society for Microbiology (ASM). The ASM is the largest single life science society, composed of over 39,000 scientists and health professionals. Its mission is to advance the microbiological sciences as a vehicle for understanding life processes and to apply and communicate this knowledge for the improvement of health and environmental and economic well-being worldwide.
Jim Sliwa | Eurek Alert!
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences