Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Test for Joint Infection Could Spare Some Patients an Unnecessary Procedure

05.03.2008
A potential diagnostic test that could help surgeons confirm or rule out the presence of infection-causing bacteria in prosthetic joints that require surgical revision has been developed by researchers at the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the National Institutes of Health (NIH).

Such a test could spare a subgroup of people who need the surgery a time-consuming and costly treatment for infection, while helping to ensure that people who need the procedure get it. The test is described in the March issue of the Journal of Bone and Joint Surgery.

Each year, hundreds of thousands of joint replacement surgeries are performed in this country. And each year, thousands of them must be revised (the prosthetic joint must be removed and replaced) due to severe pain and swelling. These symptoms are often due to infection, says Rocky S. Tuan, Ph.D., chief of NIAMS' Cartilage Biology and Orthopaedics Branch.

The standard treatment for suspected infection is to remove the joint prosthesis and replace it with a spacer that has been impregnated with antibiotics. After about six weeks, patients must undergo another surgery to remove the spacer. Only then can the surgeon implant the new prosthesis.

The problem with this approach is that confirming the presence of infection-causing bacteria is an inexact science. Currently, doctors check for infection by culturing a sample of the joint fluid. A positive culture confirms live bacteria, making spacer surgery a certainty. A negative culture, however, does not necessarily mean there is no infection. In fact, Tuan says that estimates of the false negative rate for joint cultures in revision surgeries range from 27 percent to 50 percent. But because failure to treat an infected joint could lead to severe infection and limb amputation, spacer surgery is sometimes performed for safety's sake even when infection test results are inconclusive.

To get around the false-negative problem, Tuan and his colleagues developed a way to test for joint infections using polymerase chain reaction (PCR), which detects the presence of bacterial DNA. However, this approach proved to have pitfalls, too. It picked up all bacteria — even dead or dying bacteria that cannot perpetuate infection — thereby giving false positives.

Tuan says this new problem led them to expand their PCR approach by testing for bacterial messenger ribonucleic acid (mRNA). "When bacteria are dying, their mRNA is one of the first things to go," he says. As a result, the researchers hypothesized that a good mRNA test would not only detect bacteria, but would likely tell them if any bacteria they detected were still viable. Unlike DNA, mRNA is not directly quantifiable by known techniques, so the mRNA test that Tuan's group developed employs a process called reverse transcription PCR (RT-PCR) to convert the mRNA into DNA for measurement.

Tuan's group tested the validity of their new method by introducing bacteria into infection-free joint fluid to simulate infection. To ensure that the bacteria were indeed present, they used the PCR test, which accurately showed the amount of bacterial DNA. The researchers then treated the joint fluid cultures with potent antibiotics designed to kill off the bacteria. As expected, the PCR-DNA test still showed that the fluid contained plenty of bacteria, but when the group analyzed the cultures with the RT-PCR test for mRNA, they found that the viable bacteria population was declining.

Now Tuan's team is recruiting 50 people who need joint revision for a clinical trial that will involve testing patients' joint fluid for bacteria and then following them for 6 months to a year after surgery. They hope that the results from this study will validate the protocol to identify or rule out infections before a person begins a surgical revision.

Tuan would like to be able to tell patients who need infection treatment, "There is a really bad infection and we know what to do."

"But we also want to tell the person without infection that it's O.K. to put in a revision joint. That saves the spacer, the additional surgery and its associated risk, and 6 weeks of being laid up," Tuan says.

The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the Department of Health and Human Services' National Institutes of Health (NIH), is to support research into the causes, treatment, and prevention of arthritis and musculoskeletal and skin diseases; the training of basic and clinical scientists to carry out this research; and the dissemination of information on research progress in these diseases. For more information about NIAMS, call the information clearinghouse at (301) 495-4484 or (877) 22-NIAMS (free call) or visit the NIAMS Web site at http://www.niams.nih.gov.

The National Institutes of Health (NIH) — The Nation's Medical Research Agency — includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

Reference:
Birmingham P et al. Simulated joint infection assessment by rapid detection of live bacteria with real-time reverse transcription polymerase chain reaction. J Bone Joint Surg Am 2008;90:602-08.

Trish Reynolds | EurekAlert!
Further information:
http://www.nih.gov
http://www.niams.nih.gov

More articles from Health and Medicine:

nachricht New method uses just a drop of blood to monitor lung cancer treatment
18.10.2018 | Osaka University

nachricht Photoactive bacteria bait may help in fight against MRSA infections
12.10.2018 | Purdue University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Goodbye, silicon? On the way to new electronic materials with metal-organic networks

Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz (Germany) together with scientists from Dresden, Leipzig, Sofia (Bulgaria) and Madrid (Spain) have now developed and characterized a novel, metal-organic material which displays electrical properties mimicking those of highly crystalline silicon. The material which can easily be fabricated at room temperature could serve as a replacement for expensive conventional inorganic materials used in optoelectronics.

Silicon, a so called semiconductor, is currently widely employed for the development of components such as solar cells, LEDs or computer chips. High purity...

Im Focus: Storage & Transport of highly volatile Gases made safer & cheaper by the use of “Kinetic Trapping"

Augsburg chemists present a new technology for compressing, storing and transporting highly volatile gases in porous frameworks/New prospects for gas-powered vehicles

Storage of highly volatile gases has always been a major technological challenge, not least for use in the automotive sector, for, for example, methane or...

Im Focus: Disrupting crystalline order to restore superfluidity

When we put water in a freezer, water molecules crystallize and form ice. This change from one phase of matter to another is called a phase transition. While this transition, and countless others that occur in nature, typically takes place at the same fixed conditions, such as the freezing point, one can ask how it can be influenced in a controlled way.

We are all familiar with such control of the freezing transition, as it is an essential ingredient in the art of making a sorbet or a slushy. To make a cold...

Im Focus: Micro energy harvesters for the Internet of Things

Fraunhofer IWS Dresden scientists print electronic layers with polymer ink

Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed...

Im Focus: Dynamik einzelner Proteine

Neue Messmethode erlaubt es Forschenden, die Bewegung von Molekülen lange und genau zu verfolgen

Das Zusammenspiel aus Struktur und Dynamik bestimmt die Funktion von Proteinen, den molekularen Werkzeugen der Zelle. Durch Fortschritte in der...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Conference to pave the way for new therapies

17.10.2018 | Event News

Berlin5GWeek: Private industrial networks and temporary 5G connectivity islands

16.10.2018 | Event News

5th International Conference on Cellular Materials (CellMAT), Scientific Programme online

02.10.2018 | Event News

 
Latest News

RUDN chemist tested a new nanocatalyst for obtaining hydrogen

18.10.2018 | Life Sciences

Massive organism is crashing on our watch

18.10.2018 | Earth Sciences

Electrical enhancement: Engineers speed up electrons in semiconductors

18.10.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>