Explainer: what are superbugs and how can we control them?

Superbugs are routine bacteria that have learnt how to avoid being killed by antibiotics. When this ability extends across multiple different types (classes) of antibiotics, the bugs are deemed multi-drug resistant (MDR) and qualify as “superbugs”.

Broadly speaking, superbugs can be split into four categories of bugs that infect the skin, airways, sexual organs and the gut.

1. Skin

Bugs found on the skin, such as “golden staph” (also called MRSA or Methicillin-resistant Staphylococcus aureus) cause skin infections and infections associated with skin-penetrating procedures such as intravenous (IV) lines and surgical operations.

IV drug users are also at increased risk of these superbugs.

In hospital, these bugs are readily transmitted between patients on the hands of health-care workers and shared equipment. This risk can be mitigated with good hand hygiene and the use of alcohol-based hand sanitisers. Alcohol is fatal to this superbug while leaving healthy protective skin bacteria untouched.

2. Airways

Superbugs can colonise and infect the upper airways, including the sinuses, inner ear, throat and lungs.

Because many respiratory viruses can mimic bacterial infections, antibiotics are often inappropriately used to treat viral respiratory tract infections. This has resulted in widespread resistance among many common respiratory bacteria.

The use of rapid diagnostic tests to accurately differentiate viral versus bacterial respiratory infections can improve the appropriate use of antibiotics and minimise emergence of resistance.

Pneumonia vaccines can also reduce disease rates and therefore prevent the need for antibiotics.

Transmission between patients and in crowded locations is a key challenge. There is some evidence to suggest it can be prevented with the use of simple face masks.

3. Sex organs

Sexually transmitted infections, whether viral (HIV, herpes) or bacterial (chlamydia, gonorrhoea, syphilis) are a major source of emerging superbugs. This is especially so in regions with high rates of unprotected sexual activity and prostitution, often near major military bases.

Cases of gonorrhoea resistant to all known antibiotics have recently been reported. Because no vaccines are available, superbug prevention largely depends on the regular use of condoms, increased rates of male circumcision and changes in human sexual behaviour. But uptake of these has proven difficult despite numerous public educational campaigns. Thus, STD superbugs are certain to increase.

4. Gut

Gastrointestinal superbugs can not only complicate major intrabdominal problems (such as appendicitis and gall bladder disease), they are also the key cause of urinary tract infections (UTIs) and infections following gynaecology and prostate surgery.

The sinister feature of gut superbugs is that they can silently replace the healthy gut bacteria without the person realising, then only come to light when an infection occurs.

In the meantime, the faeces is highly infectious. Environmental contamination (associated with faecal incontinence) or contamination of drinking water due to inadequate or broken sewerage systems results in widespread dissemination.

Such gut superbugs can be identified by culturing the faeces, but this is relatively expensive and accurate identification of the myriad of resistance genes requires specialist laboratory skills. Nevertheless, we have now entered a phase where this will be necessary for many patients undergoing otherwise simple surgery.

Tracking down how many patients and relatives have become faecally colonised and the extent of the hospital contamination is likely to be time-consuming and expensive.

Stopping superbugs in their tracks

Around the world, many health systems are struggling to identify which practical control strategies work best.

Cleaning hospitals with bleach-based agents has proven to reliably control environmental contamination and reduce patient-to-patient superbug transmission in most circumstances. At my hospital, Austin Health, all cleaning is now done solely with bleach. But cleaners need to be specially trained to use the product correctly.

All hospitals will now need to adopt such enhanced standards if we are to control the multitude of known gut superbugs.

To complicate matters further, the food supply in some countries is now contaminated with gut superbugs, due to uncontrolled antibiotic use in farm animals. Simply eating such food can lead to gut superbug acquisition.

We are now entering a dangerous time in the control of superbugs. For each of the four superbug categories we know the control solutions but ensuring these get implemented is a key challenge to our health system and society.

Prof. M. Lindsay Grayson previously received funding from the NHMRC. He is currently director of Hand Hygiene Australia, which runs the National Hand Hygiene Initiative. He is one of three patent holders for a hand sanitiser, the royalties for which go to Austin Health.