The rise of multidrug resistance in gonorrhoea-causing bacteria is threatening to make this sexually-transmitted infection extremely difficult to treat.

Professor Catherine Ison, from Health Protection Agency (HPA) in London, speaking at the meeting, highlights the very real possibility that strains of Neisseria gonorrhoeae resistant to all current treatment options could emerge in the near future.

She described how some strains of the gonococcal bacteria that cause the disease, are now showing decreased sensitivity to the current antibiotics used to treat them - ceftriaxone and cefixime, threatening to join MRSA , and come lately gram-negative bacteria.

Gonorrhoea is the second most common bacterial sexually-transmitted infection and if left untreated can lead to pelvic inflammatory disease, ectopic pregnancy and infertility in women. Current treatment consists of a single dose of antibiotic given in the clinic when prescribed, by mouth for cefixime and by injection for ceftriaxone.

"Choosing an effective antibiotic can be a challenge because the organism that causes gonorrhoea is very versatile and develops resistance to antibiotics very quickly," explains Professor Ison.

"Penicillin was used for many years until it was no longer effective and a number of other agents have been used since. The current drugs of choice, ceftriaxone and cefixime, are still very effective but there are signs that resistance particularly to cefixime is emerging and soon these drugs may not be a good choice," she said.



Bacteria isolated from patients diagnosed with gonorrhoea are tested for their susceptibility to various antibiotics to monitor patterns of resistance at a local and national level. Ongoing monitoring of antimicrobial resistance is critical to ensure that first-line treatments for gonorrhoea remain effective.

"There are few new drugs available. It is probable that the current use of a single dose may soon need to be revised, and treatment over several days or with more than one antibiotic will need to be considered," she warns. "If this problem isn't addressed then there is a real possibility that gonorrhoea will become a very difficult infection to treat," she said.

Personalised modelling approach
What makes some viral infections fatal and others much less severe is largely a mystery. It is thought that a part of the variability can be attributed to differences in how individuals respond to infection.



Professor Michael Katze, (left) from the University of Washington in Seattle,  focus is on computer modelling as a powerful tool to allow treatments to be tailored to individuals, an approach could ultimately prevent future pandemics.

He explains how 'systems biology' methods could successfully tackle viral infections, such as HIV and hepatitis C virus, for which there is still no effective vaccine or treatment.



"Systems biology is like a Rubik's cube - it's a matrix that integrates computational models, experimental systems and high-throughput data in a variety of combinations to solve the puzzle of virus-host interactions. It provides a powerful new approach to virology, drug discovery and vaccine development," says Professor Katze.



Computer models (right) of the whole cell can be made and tested by simulating virus-induced changes and monitoring the whole cell response. Comparing the model to real biological examples allows the model to be refined and allows researchers to make further predictions about how different cells respond to different changes. 

Improved animal models may help us understand how differences in an individual's genetic make-up affect HIV development.

"Determining which host genes affect HIV progression has been relatively slow using the current techniques in isolation," he comments remarks. "Some current studies indicate there is a link between genes that affect how virus particles enter the host cell and the disease progression," he adds.



Identifying the molecules produced from these host genes could provide a method to effectively detect disease, predict how individuals respond to infection and even establish how effective a vaccine is.

"If this becomes as easy as doing a simple blood test, we will be equipped to provide the most effective treatment to the individual. This will limit the spread of the virus, which in turn could help protect the population as a whole and even prevent the next pandemic," he suggests.

Stimulant identified: now to work on response
Stimulating single living cells with light and microparticles. Biophysicists at Yale created a method to stimulate single living cells with light and microparticles. Left side: The five particles pictured are trapped with laser tweezers and release a chemical which attracts the cell. Right side: The cell encounters a larger chemical concentration close to the particles (white-yellow region) than further away from the particles (red-black region). Credit: Holger Kress and Eric Dufresne.

Dr Holger Kress (left) describes a new technique pioneered by himself and Professor Eric Dufresne (right) at Yale University, that uses sponge-like micro-particles to mimic bacteria.



The micro-particles slowly release a characteristic bacterial "scent" that is picked up by immune cells, causing them to actively move towards the source of the chemical in an attempt to hunt down the model microbes.

Micro-particles can be trapped and manipulated three-dimensionally using 'optical tweezers' - highly focussed laser beams that are able to precisely control the movement of the particles to within a millionth of a millimetre.

"By controlling the shape of the chemical signals, we were able to control the movements of immune cells and study how they respond to the signals," says Dr Kress.



The scientists found that a single chemical-releasing micro-particle was enough to encourage neutrophils (a type of immune cell) to migrate towards it. Within less than one minute's exposure to the micro-particle, the neutrophils were able to polarise the growth of their internal 'skeleton' in the direction of the chemical.



Dr Kress explained that although researchers had successfully identified the types of chemical signals that stimulate immune cells, it is still a challenge to work out the exact details of the immune cell response.

"This new technique allows us to measure systematically how cells respond to various stimuli over minute gradients in time and space," 

he says and believes his technique could be applied across a wide range of research fields. "Cell migration along chemical gradients of this kind plays a key role in wound healing and the wiring of the brain. It is also an essential feature of many diseases - particularly metastatic cancers."