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!
A new potential biomarker for cancer imaging
05.02.2016 | Universiti Putra Malaysia (UPM)
NIH researchers identify striking genomic signature shared by 5 types of cancer
05.02.2016 | NIH/National Human Genome Research Institute
Automobiles increase the mobility of their users. However, their maneuverability is pushed to the limit by cramped inner city conditions. Those who need to...
Advance in biomedical imaging: The University of Würzburg's Biocenter has enhanced fluorescence microscopy to label and visualise up to nine different cell structures simultaneously.
Fluorescence microscopy allows researchers to visualise biomolecules in cells. They label the molecules using fluorescent probes, excite them with light and...
NASA's follow-on to the successful ICESat mission will employ a never-before-flown technique for determining the topography of ice sheets and the thickness of sea ice, but that won't be the only first for this mission.
Slated for launch in 2018, NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) also will carry a 3-D printed part made of polyetherketoneketone (PEKK),...
In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister picture is being painted evoking the demise of the island states and their cultures. Are the effects of sea-level rise already noticeable on reef islands? Scientists from the ZMT have now answered this question for the Takuu Atoll, a group of Pacific islands, located northeast of Papua New Guinea.
In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister...
The ‘Internet of Things’ is growing rapidly. Mobile phones, washing machines and the milk bottle in the fridge: the idea is that minicomputers connected to these will be able to process information, receive and send data. This requires electrical power. Transistors that are capable of switching information with a single electron use far less power than field effect transistors that are commonly used in computers. However, these innovative electronic switches do not yet work at room temperature. Scientists working on the new EU research project ‘Ions4Set’ intend to change this. The program will be launched on February 1. It is coordinated by the Helmholtz-Zentrum Dresden-Rossendorf (HZDR).
“Billions of tiny computers will in future communicate with each other via the Internet or locally. Yet power consumption currently remains a great obstacle”,...
02.02.2016 | Event News
26.01.2016 | Event News
26.01.2016 | Event News
05.02.2016 | Life Sciences
05.02.2016 | Materials Sciences
05.02.2016 | Physics and Astronomy