As the saying goes, “there ain’t no flies on us, there ain’t no flies on us, there may be flies on some of you guys but there ain’t no flies on us!”
I had a great question last week from Michael Kamdar who asked me “if a healthcare professional who works within a hospital would have the flora of that of a normal person within the community or within a hospital?” Great question! And although I have no specific resources I can comment from experience… Firstly let’s go over the normal flora of non-hospitalised people.
I had a great question last week from Michael Kamdar who asked me “if a healthcare professional who works within a hospital would have the flora of that of a normal person within the community or within a hospital?” Great question! And although I have no specific resources I can comment from experience… Firstly let’s go over the normal flora of non-hospitalised people.
image from www.evolution.berkeley.edu
Did you know there are 15,000 times more bacteria on 1 person than there are people on the planet; each of us is host 100,000,000,000,000 little “friends” and in general we tend to live in harmony for most of the time? This is normal flora, and you can learn more about it under Basic Concepts on this website.
If something “happens” to disrupt our normal flora then the types of bacteria present start to change; we become colonised with other abnormal flora. This doesn’t necessarily make us sick but it does mean if one of these bacteria get into a part of the body where it shouldn’t be then we would get a different infection compared to if it was one of our normal flora getting somewhere it shouldn’t be e.g. Streptococcus pneumoniae versus Klebsiella pneumoniae causing pneumonia. From about day 4 of admission this is what “happens” to hospitalised patients, it takes this long for normal flora to be disrupted or abnormal flora to become established. This is also why the antibiotics used to treat “hospital-acquired” or “healthcare-associated” infections are different; the infection isn’t any worse, it’s the causative bacteria that are different.
There are a number of reasons why our flora in hospital changes:
So patients in hospital have “abnormal” normal flora…
…but what about people who work in hospitals?
Healthcare worker normal flora
The bottom line is that Healthcare Workers (HCW) have the same normal flora as people who do not work in healthcare. This might sound counter intuitive and you might think that we have the same exposure to resistant bacteria as our patients and this is true, but we have one thing that protects us… we have our own normal flora! No empty house for unwanted squatters to take root.
Remember, it is disruption of normal flora that precedes the development of the hospitalised flora. If our normal flora isn’t disrupted then there is no space for the abnormal flora to get in; our normal flora fights off the invaders. Although I hear the argument that HCWs are stressed! Happily it’s not the same.
Cunningly, almost all microorganisms have some form of defence against other organisms. For some it is a way to get around host defence but for others it is fighting off competitors for resources. The best known of these mechanisms are antibiotics. Most antibiotics are naturally occurring compounds produced by microorganisms; weird that we use them against other microorganisms hey?! Many are from fungi e.g. penicillins, but others are from bacteria of the Streptomyces spp. e.g. Erythromycin, Vancomycin or Tetracycline. Bacteria produce these antibiotics to kill off competitors and maintain their own ecological position (they protect the land their house is built on).
So as HCWs our biggest and best defence against colonisation with abnormal flora is our own normal flora.
What proof is there for this?
The proof of this comes from studying outbreaks of infections in hospitals. When MRSA first became a big problem in the 1980s and 1990s there was a lot of time and resource spent looking for HCW who might be colonised and spreading the bacterium between patients. In fact some countries used to insist on negative screening swabs before they would allow overseas HCW to work in their hospitals (something currently being proposed for Covid-19 in some hospitals).
What we learned from all of this was that sometimes HCW are colonised with MRSA by the end of their shifts BUT by the following shift they were negative again. Their own flora pushed out the MRSA and they were only temporarily colonised. Screening HCW was of no value in almost all outbreak settings. NB very occasionally you might find a HCW who is a “source of infection” but it is very much the exception and only considered after much searching for other more likely sources.
And it’s not just MRSA; the same situation occurs with all sorts of hospital-associated bacteria. HCWs are temporarily colonised then their normal flora re-exerts itself.
What if healthcare workers are unwell?
If HCWs become unwell and are admitted to hospital then they change their normal flora just the same as anyone else. However problems can occur when a HCW is unwell but not admitted to hospital and continues to work in the hospital environment.
If you are a HCW who is on antibiotics for some minor infection, or steroids for your asthma, or are really just physiologically stressed and run down (like you’ve been working long hours caring for sick patients with a certain nasty virus) then it is possible that YOU WILL become colonised with abnormal flora in the same way as your patients. If you then develop a more serious infection during this time then it will be with bacteria more representative of a hospitalised patient than a community patient.
As a Microbiologist I always take note of someone’s HCW status and what has happened to them recently e.g. antibiotics, steroid use etc., because if their normal flora might have changed then they need treating like a hospitalised patient right from admission e.g. if they have pneumonia they may need treating for hospital-acquired pneumonia (HAP) on day 1 rather than community-acquired pneumonia (CAP) or switching to a HAP regime on day 4.
So as a healthcare worker what should I do?
Well it will come as no surprise that the number 1 most important thing to prevent colonisation with abnormal bacteria is to WASH YOUR HANDS and wear PPE if directed. Sound familiar… your infection control team have told you that before haven’t they!?!
Secondly, if you are unwell and taking antibiotics you should consider not coming to work. Staying at home will reduce the opportunity for abnormal colonisation whilst your normal flora is struggling. I appreciate managers might not like this message but it is sound advice. If you are taking long term medication, this is not practical so you’ll need to be especially careful with your infection control practises.
Thirdly, look after your normal flora. Normal flora is good; you need your normal flora. Keep it healthy by doing as little possible to disrupt it, like taking unnecessary antibiotics or other drugs.
Hey! Maybe, I can come up with a research project to show that chocolate is good for my normal flora… or maybe toffee; I do like Thornton’s toffee….
If something “happens” to disrupt our normal flora then the types of bacteria present start to change; we become colonised with other abnormal flora. This doesn’t necessarily make us sick but it does mean if one of these bacteria get into a part of the body where it shouldn’t be then we would get a different infection compared to if it was one of our normal flora getting somewhere it shouldn’t be e.g. Streptococcus pneumoniae versus Klebsiella pneumoniae causing pneumonia. From about day 4 of admission this is what “happens” to hospitalised patients, it takes this long for normal flora to be disrupted or abnormal flora to become established. This is also why the antibiotics used to treat “hospital-acquired” or “healthcare-associated” infections are different; the infection isn’t any worse, it’s the causative bacteria that are different.
There are a number of reasons why our flora in hospital changes:
- Antibiotics – if someone is given an antibiotic it will kill off the sensitive bacteria in someone’s normal flora leaving behind resistant bacteria or creating an ecological niche for new resistant bacteria to exploit; this is one of the main drivers for antibiotic resistance (think empty house and squatters move in!)
- Stress – Physiological stress on the body does lots of things including suppressing the production of gastric acid, which in turn allows bacteria from the bowel to “swim” up the mucosal lining of the gut and colonise the upper gastrointestinal or respiratory tract; this is why hospitalised patients often have bacteria such as Klebsiella spp. and E. coli in the sputum samples (gross hey!)
- Environmental bacteria – the hospital environment contains bacteria from vast numbers of different individuals and so people in hospital come in to contact with lots of different bacteria, many of which are not part of normal flora e.g. Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Acinetobacter baumannii; if the hospital environment is not kept clean then hospitalised patients can become colonised with these environmental bacteria.
So patients in hospital have “abnormal” normal flora…
…but what about people who work in hospitals?
Healthcare worker normal flora
The bottom line is that Healthcare Workers (HCW) have the same normal flora as people who do not work in healthcare. This might sound counter intuitive and you might think that we have the same exposure to resistant bacteria as our patients and this is true, but we have one thing that protects us… we have our own normal flora! No empty house for unwanted squatters to take root.
Remember, it is disruption of normal flora that precedes the development of the hospitalised flora. If our normal flora isn’t disrupted then there is no space for the abnormal flora to get in; our normal flora fights off the invaders. Although I hear the argument that HCWs are stressed! Happily it’s not the same.
Cunningly, almost all microorganisms have some form of defence against other organisms. For some it is a way to get around host defence but for others it is fighting off competitors for resources. The best known of these mechanisms are antibiotics. Most antibiotics are naturally occurring compounds produced by microorganisms; weird that we use them against other microorganisms hey?! Many are from fungi e.g. penicillins, but others are from bacteria of the Streptomyces spp. e.g. Erythromycin, Vancomycin or Tetracycline. Bacteria produce these antibiotics to kill off competitors and maintain their own ecological position (they protect the land their house is built on).
So as HCWs our biggest and best defence against colonisation with abnormal flora is our own normal flora.
What proof is there for this?
The proof of this comes from studying outbreaks of infections in hospitals. When MRSA first became a big problem in the 1980s and 1990s there was a lot of time and resource spent looking for HCW who might be colonised and spreading the bacterium between patients. In fact some countries used to insist on negative screening swabs before they would allow overseas HCW to work in their hospitals (something currently being proposed for Covid-19 in some hospitals).
What we learned from all of this was that sometimes HCW are colonised with MRSA by the end of their shifts BUT by the following shift they were negative again. Their own flora pushed out the MRSA and they were only temporarily colonised. Screening HCW was of no value in almost all outbreak settings. NB very occasionally you might find a HCW who is a “source of infection” but it is very much the exception and only considered after much searching for other more likely sources.
And it’s not just MRSA; the same situation occurs with all sorts of hospital-associated bacteria. HCWs are temporarily colonised then their normal flora re-exerts itself.
What if healthcare workers are unwell?
If HCWs become unwell and are admitted to hospital then they change their normal flora just the same as anyone else. However problems can occur when a HCW is unwell but not admitted to hospital and continues to work in the hospital environment.
If you are a HCW who is on antibiotics for some minor infection, or steroids for your asthma, or are really just physiologically stressed and run down (like you’ve been working long hours caring for sick patients with a certain nasty virus) then it is possible that YOU WILL become colonised with abnormal flora in the same way as your patients. If you then develop a more serious infection during this time then it will be with bacteria more representative of a hospitalised patient than a community patient.
As a Microbiologist I always take note of someone’s HCW status and what has happened to them recently e.g. antibiotics, steroid use etc., because if their normal flora might have changed then they need treating like a hospitalised patient right from admission e.g. if they have pneumonia they may need treating for hospital-acquired pneumonia (HAP) on day 1 rather than community-acquired pneumonia (CAP) or switching to a HAP regime on day 4.
So as a healthcare worker what should I do?
Well it will come as no surprise that the number 1 most important thing to prevent colonisation with abnormal bacteria is to WASH YOUR HANDS and wear PPE if directed. Sound familiar… your infection control team have told you that before haven’t they!?!
Secondly, if you are unwell and taking antibiotics you should consider not coming to work. Staying at home will reduce the opportunity for abnormal colonisation whilst your normal flora is struggling. I appreciate managers might not like this message but it is sound advice. If you are taking long term medication, this is not practical so you’ll need to be especially careful with your infection control practises.
Thirdly, look after your normal flora. Normal flora is good; you need your normal flora. Keep it healthy by doing as little possible to disrupt it, like taking unnecessary antibiotics or other drugs.
Hey! Maybe, I can come up with a research project to show that chocolate is good for my normal flora… or maybe toffee; I do like Thornton’s toffee….
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