Seminar blog | How do you solve a problem like resistance?

On 2 August, the AMR Centre was fortunate enough to hear from Dr Catriona Bradshaw about the management of antimicrobial resistance, with a focus on Mycoplasma genitalium.

Dr Bradshaw is based at the Melbourne Sexual Health Centre where she works as a consultant and holds Associate Professorial positions at the Central Clinical School, Monash University and the School of Population and Global Health, University of Melbourne. She has a strong interest in clinical and epidemiological research in sexually transmitted infections and a particular focus on bacterial vaginosis, the vaginal microbiome and M. genitalium.

M. genitalium: asymptomatic, undetected…

M. genitalium is a sexually transmitted infection and has been associated with a number of inflammatory conditions, including inflammation of the cervix (cervicitis), the urethra (non-gonococcal urethritis), and infection of the female upper genital tract (pelvic inflammatory disease). However, M. genitalium can also infect someone without resulting in any symptoms (known as asymptomatic), which can be problematic when trying to stop the bacteria from spreading. Furthermore, many clinics often lack the diagnostic tools necessary to identify M. genitalium, meaning that treatment is performed on a presumptive basis: based on the symptoms that the individual has. This all adds up to a bacteria that is very difficult to manage and control.

…and resistant

Unfortunately, research has shown that over the last ten years M. genitalium is developing resistance to the front-line antibiotic routinely used for treating it, azithromycin. Furthermore, the typical backup-treatment choice, moxifloxacin, is also beginning to become less effective; with M. genitalium showing signs of becoming resistant in areas where moxifloxacin is used. For example, in the Asia-Pacific, of the M. genitalium strains tested, between 15–30% have been identified as being resistant to both azithromycin and moxifloxacin.

When the first and second choices fail, what next?

Dr Bradshaw discussed how research in this area has encouraged a review of the use of azithromycin in sexually transmitted infections, as well as how developing resistance assays (to ascertain if an individual has a drug-resistant form of bacteria), establishing surveillance, and producing new classes of drugs are becoming areas of increased interest. However, receiving funding for research into the production of new drugs can be difficult, so more work is being conducted to explore whether existing drugs can act as a source of new antimicrobial treatments, as well as trialling new drug combinations to delay the emergence of resistance. For example, changing the first-line therapy to a different antibiotic, doxycycline, and then identifying and using a second drug that the bacteria is not resistant to, was shown to achieve a cure rate of 92–95%.

Although identifying new, successful drug combinations is crucial, there is a strong warning underlying this approach. Dr Bradshaw emphasised that although being able to treat patients using tailored approaches seems to improve treatment effectiveness, if financial support is not provided for the development of new classes of antibiotics, we are only stalling the time before the bacteria becomes resistant to the new combination. In order to break this cycle, we need to consider carefully how we approach this increasing problem of resistance.

Missed the seminar?

For more details of Dr Bradshaw and the seminar, visit our website.

 

And keep checking our Upcoming Events page for future seminars and events.

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