Drug resistance genes shared among bacteria in hospitals can be deadly

June 10, 2018, American Society for Microbiology

A hospital outbreak of carbapenem-resistant Enterobacteriaceae (CRE) became more worrisome when researchers found resistance genes being shared among unrelated bacteria via plasmids and other mobile genetic elements. This new research will be presented at ASM Microbe, the annual meeting of the American Society for Microbiology, held from June 7th through June 11th in Atlanta, Georgia.

In 2017, eighteen patients in a primary care hospital became sick with CRE, a family of responsible for more than 9,000 healthcare-associated infections (HAI) per year in the United States. Carbapenems are often used as last line treatment options, reserved for the sickest patients; so it is concerning when bacteria resistant to these drugs cause infections.

Outbreaks of CRE infections are often caused by closely related bacteria spreading from person-to-person or even from a common source, such as a contaminated medical device. In such cases, control efforts focus on eliminating transmission of a single strain of bacteria. In this outbreak, however, multiple types of CRE (i.e., different bacterial strains and species) were infecting patients, and whole genome sequencing revealed that the outbreak was likely perpetuated by carbapenem being shared among unrelated bacteria via plasmids or other mobile genetic elements.

"This demonstrates the important role whole genome sequencing can play in investigating HAI outbreaks," said Richard Stanton, "This outbreak shows us how drug resistance can be shared among otherwise unrelated bacteria co-existing in a patient's microbial community or in the environment." This in turn may require expanding and detection efforts to include multiple strains and species to halt the outbreak.

The bacteria involved in this included Klebsiella pneumonia and Escherichia coli, two species of bacteria that can cause a variety of healthcare-associated infections, including pneumonia, bloodstream infections, , and meningitis. Treatment of the infections in these outbreaks was complicated due to the presence of carbapenemase genes in the bacteria, of which two major variants of the Klebsiella pneumonia Carbapenemase (KPC) gene (KPC-2 and KPC-3) were found.

The bacterial strains with the KPC-2 gene were largely unrelated but all carried the same drug resistance plasmid. Similarly, the strains with the KPC-3 gene were quite diverse except they all shared a plasmid, common among the KPC-3 strains but different from the KPC-2 strains.

"Due in part to this finding, HAI investigations now include a broader scope to look not just for single species causing infections, but also for plasmids spreading across multiple types of bacteria," said Dr. Stanton. Infection control efforts also focus on areas where plasmid sharing is likely to occur in the healthcare environment, such as in sinks and drains.

Vaneet Arora, Lorrie Sims, and Rachel Zinner from the Kentucky Department for Public Health isolated and cultured the bacterial samples used in this study. Jonathan Daniels, Alison Laufer Halpin, and Richard Stanton from the Division of Healthcare Quality Promotion at the Centers for Disease Control and Prevention performed whole genome sequencing and analysis of the isolates.

This work was made possible through CDC's investments to Combat Antibiotic Resistant Bacteria and the Advanced Molecular Detection Program at CDC. A poster highlighting this work will be presented by Richard Stanton at the ASM Microbe 2018 conference in Atlanta, GA on June 10th from 12:45—2:45 PM, as part of Session 420—Infection Prevention and Control: Drug-Resistant Pathogens in Hospitals.

Explore further: Antibiotic-resistant bacteria found in the US presents a triple threat

Related Stories

Antibiotic-resistant bacteria found in the US presents a triple threat

June 9, 2018
Researchers from the Emory Antibiotic Resistance Center describe the first strain of carbapenem-resistant, hypermucoviscous Klebsiella pneumoniae exhibiting colistin heteroresistance and enhanced virulence isolated from a ...

Antibiotic-resistant plasmids flourish in hospital plumbing

February 6, 2018
Antibiotic-resistant organisms can be found in multiple locations in a hospital - on countertops and doorknobs, on computers and in sinks, and even inside the plumbing. To better understand how these organisms spread, investigators ...

Three Klebsiella species cause life-threatening infections and share drug resistance genes

August 2, 2017
A team of US researchers has discovered that three different species of Klebsiella bacteria can cause life-threatening infections in hospital patients and that all three share genes that confer resistance to the most commonly ...

Recommended for you

Recent clinical trial finds tamsulosin not effective in kidney stone passage

June 18, 2018
The latest research into finding medications to aid the passage of ureteral or kidney stones has shown that tamsulosin is not effective for patients across the board. Previously approved to help men experiencing enlarged ...

Research finds new way to determine protection of Men B vaccine against different strains

June 18, 2018
Researchers at the University of Leicester and Meningococcal Reference Unit have developed a new approach to assess the effectiveness of the Men B vaccine, Bexsero, against different strains that cause meningococcal meningitis ...

Novel molecular target to prevent scarring of the lung blood vessels identified

June 13, 2018
Pulmonary arterial hypertension, a severe form of cardiopulmonary disease in which the arteries that transport blood from the heart to the lungs become thickened, constricted, and scarred, is a disease for which there is ...

Lineage of TB traced and compared to early human migration

June 13, 2018
A team of researchers from the University of Wisconsin, the University of Iowa and the Norwegian Institute of Public Health has carried out genetic studies of tuberculosis to learn more about its lineage and to compare it ...

Fast-acting cholera vaccine could curb outbreaks

June 13, 2018
A tricked-out cholera vaccine starts protecting against the deadly disease within a day, experiments in rabbits suggest. The rapid protection offered by this designer vaccine may one day limit the spread of cholera outbreaks, ...

Finally, hope for a syphilis vaccine

June 12, 2018
Despite efforts to eradicate it, syphilis is on the rise. Until now, most health agencies focused on treating infected people and their sex partners but new discoveries may make a vaccine possible, UConn Health researchers ...

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.