Featured Research

from universities, journals, and other organizations

Genes Involved In Antibiotic Resistance Vary Within A Species

Date:
December 24, 2008
Source:
Case Western Reserve University
Summary:
When comparing the genome sequence of three MDR A. baumannii isolates and three drug-susceptible A. baumannii isolates, scientists found that one variation of bacteria would respond to antibiotics while another variation of the same bacteria may not.

The recent emergence of multidrug resistance (MDR) in Acinetobacter baumannii, a bacteria that causes infections primarily among seriously ill patients in the intensive care unit who may have reduced immune systems, has raised concern in health care settings worldwide. When comparing the genome sequence of three MDR A. baumannii isolates and three drug-susceptible A. baumannii isolates, Case Western Reserve University School of Medicine found that one variation of bacteria would respond to antibiotics while another variation of the same bacteria may not.

Related Articles


A. baumannii is currently recognized by the Infectious Diseases Society of America as one of the most important pathogens threatening our health care delivery system.

Over the last 10-15 years, A. baumannii has become increasingly resistant to antibiotics and now more than one-third of infections are MDR, which means these pathogens are resistant to at least three different classes of antibiotics. This pattern of resistance to many antibiotics limits the ability of physicians to treat serious infections caused by A. baumannii.

The study was led by Mark Adams, Ph.D., Associate Professor in the Department of Genetics at Case Western Reserve University School of Medicine.

Adams first sequenced the genome of an MDR isolate and his collaborator in Buffalo, Steven Gill, Ph.D., Associate Professor of Oral Biology at SUNY Buffalo, sequenced two drug susceptible isolates to learn more about the genes (the genome contains the complete set of genes) that control resistance to antibiotics. Adams then compared the new sequence with genomes of other MDR and drug susceptible isolates, comparing six complete genomes.

What they found is that within a hospital or even a person, there can be a variation within the bacteria which means that it can affect how the infection reacts to antibiotics.

"A key conclusion of our study is that even very closely related isolates of A. baumannii can differ significantly in the set of resistance genes that they carry," said Adams. "It is known that resistance genes can be shared between bacteria (horizontal gene transfer), and it appears that this is a frequent event, with genes entering a genome and being deleted even across a single outbreak."

"We used to think—you treat this bacteria with this drug—but now we know that you have to look more carefully not just at the bacteria but at each one's genetic characteristics," said Adams. "This is an argument for targeted therapy in infectious disease because you want to select an antibiotic that will be effective against the particular genetic characteristics of the bug that's causing the infection."

The scientists also found that each isolate has a somewhat different set of genes.

"About three-fourths of the genes are shared by all the isolates, while the remainder are unique to different subsets," said Adams. "We identified 475 genes that are shared by all six clinical isolates of A. baumannii but are not present in a closely related Acinetobacter species that does not cause infections. These genes merit further study to help figure out what makes A. baumannii able to live in association with humans and cause disease."

Funding was provided by a grant from Steris Foundation to Adams and by funding from the National Institutes of Health to a collaborator in this study, Robert Bonomo, M.D., Associate Professor of Medicine, Pharmacology and Molecular Biology and Microbiology at Case Western Reserve University School of Medicine, and Geriatric Research, Education and Clinical Center and Infectious Diseases at Louis Stokes Cleveland Department of Veteran Affairs Medical Center. Dr. Bonomo published an article in 2006 about an initial outbreak at Walter Reed where a number of soldiers had the same bacteria but it was treated differently based on its genetic variations.


Story Source:

The above story is based on materials provided by Case Western Reserve University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Adams et al. Comparative Genome Sequence Analysis of Multidrug-Resistant Acinetobacter baumannii. Journal of Bacteriology, 2008; 190 (24): 8053 DOI: 10.1128/JB.00834-08

Cite This Page:

Case Western Reserve University. "Genes Involved In Antibiotic Resistance Vary Within A Species." ScienceDaily. ScienceDaily, 24 December 2008. <www.sciencedaily.com/releases/2008/12/081216131009.htm>.
Case Western Reserve University. (2008, December 24). Genes Involved In Antibiotic Resistance Vary Within A Species. ScienceDaily. Retrieved April 18, 2015 from www.sciencedaily.com/releases/2008/12/081216131009.htm
Case Western Reserve University. "Genes Involved In Antibiotic Resistance Vary Within A Species." ScienceDaily. www.sciencedaily.com/releases/2008/12/081216131009.htm (accessed April 18, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Saturday, April 18, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Un-Bee-Lievable: Bees on the Loose After Washington Truck Crash

Un-Bee-Lievable: Bees on the Loose After Washington Truck Crash

Reuters - US Online Video (Apr. 17, 2015) A truck carrying honey bees overturns near Lynnwood, Washington, spreading boxes of live bees across the highway. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Our Love Of Puppy Dog Eyes Explained By Science

Our Love Of Puppy Dog Eyes Explained By Science

Newsy (Apr. 17, 2015) Researchers found a spike in oxytocin occurs in both humans and dogs when they gaze into each other&apos;s eyes. Video provided by Newsy
Powered by NewsLook.com
Dog Flu Spreading in Midwestern States

Dog Flu Spreading in Midwestern States

AP (Apr. 17, 2015) Dog flu is spreading in several Midwestern states. Dog daycare centers and veterinary offices are taking precautions. (April 17) Video provided by AP
Powered by NewsLook.com
Raw: Rare Whale Spotted in Gulf of Mexico

Raw: Rare Whale Spotted in Gulf of Mexico

AP (Apr. 17, 2015) Researchers from the E/V Nautilus had quite a surprise Tuesday, when a curious sperm whale swam around their remotely operated vehicle in the Gulf of Mexico. Cameras captured the encounter. (April 17) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins