SpeeDx Pty. Ltd. announced that a study using a beta version of PlexPCR M. genitalium ResistancePlus shows strong results in the detection of both M. genitalium and mutations in the 23S rRNA gene of the bacteria that have been shown to confer resistance to commonly prescribed macrolide based antibiotics.

The study, Multiplex Assay for Simultaneous Detection of Mycoplasma genitalium and Macrolide Resistance using PlexZyme and PlexPrime Technology, published in PLOS ONE,  was performed in collaboration with Sepehr Tabrizi, PhD at the Royal Women's Hospital in Melbourne, Australia.

"We believe this study is a positive first step in combatting the growing problem of antibiotic resistance in M. genitalium," said Prof. Sepehr Tabrizi, senior scientist in charge at Royal Women's Hospital in Melbourne, Australia. "The SpeeDx assay provides valuable information to the clinicians in a rapid timeframe allowing for better treatment of patients infected with M. genitalium. Timely detection of potential antibiotic resistance could enable the development of better algorithms for the treatment of M. genitalium infection and promote responsible stewardship of antibiotics."

The PlexPCR M. genitalium ResistancePlus assay was evaluated in 400 samples from 254 (186 males and 68 females) consecutively infected participants, undergoing tests of cure. Using the MG 23S assay, 83 percent (331/400) of samples were positive, with 56 percent of positives carrying a macrolide resistance mutation.  Due to the detection of macrolide resistance, broad-spectrum antibiotics, including azithromycin therapy, would not be an effective treatment for more than half the patient samples included in this study.

M. genitalium is a sexually transmitted infection that can cause symptoms such as urethritis, cervicitis, endometriosis and pelvic inflammatory disease.1 It has been found to have a higher prevalence than Neisseria gonorrhoeae in recent studies2,3 and has shown to have increasing treatment failure rates due to antimicrobial resistance to macrolide based antibiotics such as azithromycin4.  M. genitalium is often misdiagnosed because its symptoms are similar to other sexually transmitted diseases and PCR testing is not widely available. Because of this, doctors usually send patient samples to a special laboratory and prescribe a broad-spectrum antibiotic while they wait for their patients' results to come back. Meanwhile, patients with resistant M. genitalium needlessly suffer continued infection.

PlexPCR and ResistancePlus constitute multiplex qPCR kits for detection of infectious disease pathogens and antimicrobial resistance markers, respectively. Powered by the company's proprietary PlexZyme and PlexPrime technologies, both product lines offer high multiplexing capability for better, more streamlined detection of infectious disease-causing pathogens. With increased ability to detect more pathogens as well as multiple genetic markers, every PlexPCR and ResistancePlus assay provides more actionable information to support laboratories and researchers alike.

Based in Sydney, Australia and founded in 2009, SpeeDx is a privately owned company specializing in innovative multiplex real-time polymerase chain reaction (qPCR) solutions for clinical diagnostics.