Is Legionella Bacteria Becoming Antibiotic Resistant?
In this article the water safety specialists at Legionella Control International look at the role of antibiotics in protecting humans against pathogenic organisms, paying particular attention to waterborne bacteria including Pseudomonas aeruginosa and legionella.
The article begins by looking at research from the World Health Organisation identifying several antibiotic resistant pathogens of concern, categorised as critical, high and medium risk. It then goes on to consider antimicrobial resistance, and the dangers of waterborne bacteria including pseudomonas and legionella. It concludes by asking if legionella bacteria are becoming resistant to antibiotics, and highlighting a number of practical risk mitigation strategies for the control of both pseudomonas and legionella risks in the workplace.
A version of this article dealing with legionella bacteria and its potential for antimicrobial resistance appeared in Legionella Control International’s newsletter. To get it in your inbox, sign up for free here.
How serious is antimicrobial resistance becoming?
Imagine you develop a bacterial infection. Home treatments are not sufficient to get rid of it, so you visit your GP to get some antibiotics. With time, and providing you take the whole course, the infection clears up and you return to normal.
Now, imagine there are no antibiotics that can treat the infection. What happens then?
This might sound unusual and unlikely, but it is a scenario that is rapidly getting closer to becoming commonplace. We have known about antimicrobial resistance for some time, and the need is becoming ever more urgent to find new ways of treating bacteria that can resist antibiotics given to combat them.
World Health Organisation (WHO) highlights priority pathogens
The idea of antibiotic resistance came to light several years ago. Back in 2017, the World Health Organisation or WHO published a list of bacteria divided into three groups – some more urgent than others – that required research to determine new ways to combat them.
The top three pathogens, classed as Priority 1, Critical were all carbapenem-resistant. Carbapenem is the name given to a class of antibiotics often used to treat organisms that are gram-positive or gram-negative. They are among the more powerful antibiotics and can treat a range of bacterial infections. The three bacteria appearing in the critical group on the list from WHO therefore require urgent attention, as we may run out of ways to treat infections caused by the pathogens.
The priority 1 pathogens, deemed critical were identified as Acinetobacter baumannii, Enterobacteriaceae and Pseudomonas aeruginosa. Pseudomonas is a germ capable of causing infections of the blood and pneumonia, a condition affecting the lungs. It may also cause relatively mild skin infections or infections of the eyes or ears. In some cases, it may not warrant treatment, especially if the individual is otherwise healthy.
WHO: Priority 1 Pathogens, Critical
- Acinetobacter baumannii
- Pseudomonas aeruginosa
- Enterobacteriaceae
However, many infections that are caused by Pseudomonas aeruginosa occur in hospitals. It can inhabit water systems, including manmade ones, and so those in hospital can be exposed to it if the circumstances allow this to occur. Since people in hospital are more likely to be weaker, perhaps recovering from surgery or other treatment, they are at greater risk as well.
For completeness, the other, priority 2 and 3 pathogens flagged by WHO and of concern were:
Priority 2 Pathogens, High
- Enterococcus faecium
- Staphylococcus aureus
- Helicobacter pylori
- Campylobacter spp.
- Salmonellae
- Neisseria gonorrhoeae
Priority 3 Pathogens, Medium
- Streptococcus pneumoniae
- Haemophilus influenzae
- Shigella spp.
What is antimicrobial resistance?
Antibiotics and other medicines are created to combat and kill various bacteria and other germs that are potentially harmful to humans. However, as with many organisms, bacteria develop and change over time. This means they can eventually evolve to a point where the threat to them (in this case, the antibiotic) is no longer a threat. The antibiotics then fail to work effectively against the bacteria they were originally created to kill, thereby causing antimicrobial resistance.
This means the bacteria can continue to grow and spread, and there is no line of defence against infections caused by them. This is concerning no matter the type of bacteria involved, but particularly so with Pseudomonas aeruginosa, a leading cause of hospital-acquired infections.
One study found that antibiotic resistance against Legionnaires’ disease was noted at between 50% and 100%
Are legionella bacteria also resistant to antibiotic treatment?
There are many strains of legionella bacteria, and research has been conducted to determine whether they may be resistant to certain types of antibiotics. Legionella pneumophila is most associated with Legionnaires’ disease, and is waterborne, and thereby able to spread throughout a manmade water system.
At present, a combination of quinolones and macrolides is used to combat cases of Legionnaires’ disease. However, antibiotics that fall into these two groups have been seen to be less effective in some cases of Legionnaires’ disease. One study performed a few years ago found that resistance against Legionnaires’ disease was noted at between 50% and 100%, which is alarming to note. While this is just one study, it does suggest that legionella bacteria could be learning how to bypass the antibiotics most used to treat it.
How do bacteria become resistant to antibiotics?
Bacteria can become resistant to antibiotics in several ways. For example, the bacteria may neutralise an antibiotic by preventing it from reaching where it needs to go to work. It may also make the antibiotic less effective even if it does reach its destination – or even destroy it altogether. In some cases, the bacteria can change its outer layer to stop the antibiotics getting through.
It may be that one type of bacteria uses one method, while another develops in a different way. However, the outcome is the same – the antibiotic that previously worked against a specific bacterium no longer has the same effect.
Perhaps most worrying of all is that a germ that is resistant to antibiotics can share this resistance with other germs. According to the US Centers for Disease Control and Prevention (CDC), germs that are useful and help protect us can also be killed by these antimicrobial resistant germs, thereby causing more than one issue.
What else can be done to combat Legionnaires’ disease?
Legionnaires’ disease is largely preventable if appropriate steps are taken to make sure legionella bacteria does not spread within a water system. We have seen this with many previous outbreaks of Legionnaires’ disease around the world. In many cases, research following an outbreak discovers that certain physical or management steps were not taken to combat the levels of legionella bacteria within a water system.
In the UK business owners and building managers responsible for health and safety – including water safety – cannot provide input into antibiotic resistance. This is a topic for those with far more specialist knowledge. However, they can focus on making sure everything is done to create a safe water system providing hot and cold water that does not allow for the colonisation of legionella bacteria, or pseudomonas – pseudomonas can become a serious issue in certain healthcare environments.
Start with a legionella risk assessment
Your risk mitigation journey all begins with a water safety or legionella risk assessment, which should identify the biggest risks in that specific water system. The risk assessment should be done by someone with experience and understanding of the potential risks and how to mitigate them correctly. In some cases, with small water systems, common sense may be enough to manage with.
However, in cases where the water systems are far more complex, such as in a hospital, for example, there should be a water safety group made up of several people, each responsible for different roles. This water safety group may also encompass someone from outside the building or company, typically referred to as an Authorising Engineer (Water) possessing the required knowledge and experience to advise on the need for a legionella risk assessment and other water engineering activities. This will vastly reduce the instance of legionella spreading throughout the water system and exposing people to Legionnaires’ disease. It’s always best if cases of Legionnaires’ disease are not allowed to develop to start with… prevention being better than cure.
Leading water safety specialists
Legionella Control International are world leading water safety specialists, supporting those responsible for the control of legionella and other waterborne pathogens in the workplace, including hospitals and other healthcare environments. Our water safety teams help keep water systems safe to use, protecting staff, visitors and others from harm.
We are experienced in the healthcare role of Authorising Engineer (Water) and can assist organisations in the development of water safety management teams, policies, and procedures to safeguard people across large scale and multi-site property portfolios, complex facilities and those considered to be higher risk. We also offer expert risk assessments, safety auditing, training and more.
If you are concerned by any of the issues raised or you would like to speak with one of our water specialists, please call us today on 0330 223 36 86.
