Infectious diseases in Australia — the next decade

As long as human behaviour and medical practices exert unpredictable effects on the microbial environment, infectious disease will continue to challenge and surprise us. Changes in host factors (eg, immunosuppression, hospitalisation), environment (eg, air travel, global warming), and adaptations of microbial pathogens (eg, HIV and severe acute respiratory syndrome [SARS]) can have unanticipated effects. Stated another way, microbial Darwinism is at play.

In the 1960s and 70s, experts thought that the war against infectious disease had been won.1 We have since recognised the naivety of this belief. Infections occur as inadvertent consequences of medical progress — during cancer chemotherapy, and after transplantation, vascular access insertion and invasive procedures. The microbial world also punishes us when, through lack of foresight, our actions are disconnected from their potential consequences, as occurred when changes in rendering practices resulted in bovine spongiform encephalopathy and variant Creutzfeldt–Jakob disease. Moreover, with mass transportation of people and animals, remote developments have local effects in ways not seen in other branches of medicine. The rapid spread of SARS and pandemic (H1N1) 2009 influenza and the acquisition of antibiotic-resistant bacteria by travellers illustrate this. Intensive animal husbandry and globalisation of food production can increase the risk of spread of gastrointestinal pathogens, while uncontrolled antibiotic use in food production has been linked to the transfer of drug-resistant enteric organisms to humans.2 Described as “the tragedy of the commons”, the pursuit of a perceived rational or short-term self-interest will ultimately compromise a shared resource.3

What are the ongoing issues for the next decade?4 Hepatitis C and HIV infection will continue to consume resources. However, both illustrate the rewards of research investment — with appropriate treatment availability, HIV is now a manageable (albeit chronic) infection, and hepatitis C is now curable in many cases. Conversely, tuberculosis (TB) presents an ongoing global challenge, with over two billion people infected and two million deaths annually. The inexorable spread of multidrug-resistant (MDR) TB is a further concern, with over half of sufferers likely to die, many with HIV coinfection. The current MDR-TB crisis in Papua New Guinea is already affecting Queensland.5 Continued spread of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) is likely, particularly in Indigenous populations, as is the transmission of MRSA, vancomycin-resistant enterococci and MDR gram-negative bacteria in hospitals and residential aged-care facilities. In South Asia, bacteria that contain New Delhi metallo-β-lactamase 1 and are thus resistant to virtually all antibiotics have emerged as a result of antibiotic overuse and poor sanitation;6 it is estimated that over 100 million people are already colonised.7 With global spread, some surgical procedures (eg, prostate biopsies) may no longer be practicable. MDR gonorrhoea now affects management of sexually transmitted diseases. Worldwide, a virulent strain of Clostridium difficile, with serious morbidity among older people, has become endemic in hospitals and is spreading to the community. Factors in its emergence are poor antibiotic prescribing practices and inadequate environmental and hand hygiene — laxities common in Australian health care.

It’s not all bad news. Translation of molecular diagnostic research is finally reaping rewards. Many new diagnostic tests are robust, fast and sensitive. TB can now be diagnosed within hours.8 Multiplex polymerase chain reaction panels have simplified viral diagnosis and screening of potential organ donors. Mass spectrometry methodologies promise to hasten microbial detection, characterisation and susceptibility testing. Genetic profiling of an individual’s infection risks will become possible, and molecular biology will help produce an expanded range of highly effective vaccines. Internet alert systems and e-health provide exciting opportunities, as do bundled prevention strategies to decrease health care infections.

It is unclear which infectious diseases will affect us most in the next decade. Regardless, Australia must robustly plan and prepare for inevitable future epidemics. Recently emerged viruses, such as SARS, Nipah and Hendra, indicate that an increasingly disturbed global environment will produce new zoonoses with local or global implications and potential spread to susceptible populations.9

Antibiotic resistance, however, is the looming issue for day-to-day infectious diseases management in Australia. The problem is obvious, yet it is largely ignored by medical and regulatory organisations for want of easy solutions.

After the 1950s, society came to believe in the infallibility of antibiotics, and they were used liberally “just in case” or as a panacea. Simultaneously, the pharmaceutical and intensive animal industries saw the opportunity to exploit their use as “growth stimulants” in animal feed.10 This freewheeling philosophy persists, despite the realisation that unabated use of antimicrobials has a sting in its tail. Most antibiotic prescribing occurs largely without scrutiny or audit. When combined with poor infection control, this results in a spiral of increasing broad-spectrum antibiotic use. The “antibiotic paradox” is that the more we use, the fewer effective drugs remain. When this laxity with antibiotics is extended to non-medical use in food production, and over-the-counter sales in some developing countries, the antibiotic paradox becomes a downward spiral. Currently, few new antibiotics are in development. For the first time in the “antibiotic era”, we are encountering untreatable infections alongside an antimicrobial void.

We have potential remedies for some of these challenges, and they do not require technical scale-up. They require professional and political will, and a commitment from doctors, veterinarians, regulators and other allied sectors. The difficult decisions are in education of consumers and physicians, in governance, and the coordination of veterinary and agricultural sectors.

To deal with antimicrobial resistance, Australia urgently needs an antimicrobial resistance management body to coordinate these efforts.11 Such bodies are already paying dividends in other forward-thinking countries. A further logical extension to deal with the broad range of infectious disease threats is the establishment of an Australian Centre for Disease Control, with strong professional leadership to support state and territory activities and coordinate surveillance, preparedness and timely responses to national health crises. To wit, AC-DC — high-voltage infection prevention and management. Is there the will and political courage to take this on in the coming decade?