Agatha Christie

Killer Bugs for Halloween: Microbes and murder through the lens of Agatha Christie

girlymicro General, Microbiology (Clinical), Science Communication, Writing , , , , , , , , , , , ,

I don’t think this is a surprise to any of the regular readers of this blog, but I adore Agatha Christie novels. Reading them has seen me through many a difficult period. They are a source of comfort, escape, and inspiration. I even wrote a previous blog about how there are parallels between solving her ‘who done its’ and my day job, as a hospital detective. What could be more Halloween than a little bit of murder, however, and so today I wanted to talk about how she uses microbes to kill in her books and why the science behind their use brings me so much joy.

Celebrating the Hospital Detectives: Why I describe Infection Prevention and Control as the detectives within our healthcare drama

When many people think of Agatha Christie murders, however, they think of her as the Queen of Poisons. They are even a number of books written about her experience as a apothecary’s assistant (pharmacy technician) during the Great War (First World War) and others breaking down her use of toxins. Most readers probably don’t necessarily think of her books having much to do with microbiology, even I hadn’t really made the link despite having listened to, read, and watched, all of her content multiple times.

I’ve been going through a difficult period at work, that combined with the hormonal chaos of the perimenopause, has led to a lot of being awake from 2 – 5am. In order to manage the anxiety I’ve been hitting the audiobooks pretty hard, and of course that has meant listening to a LOT of Christie. Imagine my surprise, therefore, that I finally clocked that although many of the deaths include death by poison, there also a few where the death featured is not by toxin, but by microbe! The excitement of this revelation probably didn’t help with the sleeping or resulting sleep deprivation, but it has inspired me to write this blog. So, not all bad then.

WARNING – THERE WILL BE SPOILERS AHEAD!

Who was Agatha Christie?

Dame Agatha Christie wrote 66 detective novels between 1916 and 1976. Her first novel, The Mysterious Affair at Styles, was written in 1916 and published in 1920. Her final work was published after her death in 1976 at the age of 85 and is one of my favourites, Sleeping Murder. Her work features so many wonderful characters, including detective characters that most people will have heard of, Hercule Poirot and Miss Jane Marple. There are many more however, including two of my favourites Tommy and Tuppence, and a girl who will forever hold a piece of my heart, Miss Ariadne Oliver, who is a novelist with some parallels to Christie herself.

Today we’re going to be talking about three main books, published over almost 30 years and featuring three different detective characters:

  • Cards on the Table, 2 November 1936, featuring Hercule Poirot (and my girl Ariadne Oliver)
  • Murder is Easy (originally Easy to Kill), 5 June 1939, featuring a one off appearance by Luke Fitzwilliam as the detective character
  • The Mirror Crack’d from Side to Side, 12 November 1962, featuring Miss Jane Marple

Cards on the Table

This book is based around a dinner party organised by Mr. Shaitana. He is an interesting chap, with an interest in collecting and also murder. He organises a dinner party with a pretty varied guest list, four detective or crime solving characters (Poirot, Oliver, Superintendent Battle, and Colonel Race), alongside four characters who may or may not have been involved with death under suspicious circumstances (Mrs. Lorrimer, Major John Despard, Dr. Geoffrey Roberts, Anne Meredith).

Shaitana is murdered after dinner, in plain sight, whilst sitting in an arm chair, as our suspects play bridge in the same room, and our detectives play bridge in another. The solving of the crime, in the most British way possible, comes down to an investigation of the Bridge hands played. On a side note as a Bridge player in my youth, albeit a very bad one, I kind of love this.

So where do the microbes come in? Not in the murder in the room, but the deaths by suspicious circumstances that one of suspects is trying to cover up.

The first murder by microbe is linked to an affair and the associated cover up, and the way it is done is pretty cool. One of our suspects has an affair with a married woman, and when he realises her husband has discovered what has happened by over hearing a conversation he takes a trip to the bathroom on the pretext of washing his hands. Whilst there he takes the opportunity to contaminate the bristles of a shaving brush with Bacillus anthracis spores, so that next time the gentleman shaves, and ideally has a few shaving cuts, the anthrax will be inoculated into the wounds.

So what would the anthrax do? The association with wounds is key, ideally a deeper cut, as there are 2 likely infectious outcomes from this. The most likely would be Cutaneous Anthrax, resulting in a surface lesion that gradually progresses to turn into a very characteristic, painless, coal-black necrotic eschar. The bacteria then release toxins that cause localised swelling. If the bacteria then enter the blood stream they then can lead to a 5% to 20% mortality rate if untreated, which of course they would be in 1936. Penicillin, which is the main treatment and fortunately the first antibiotic developed, didn’t become widely available until 1945/1946.

Even if penicillin was around it may not have helped if the bacteria entered the blood stream, as you would usually like to use either ciprofloxacin or doxycycline plus one or two additional active antibiotics like vancomycin, imipenem, or meropenem – none of which would be available for some time.

If the inoculation had been deeper, he may have developed Subcutaneous Anthrax, which could result in deep tissue infection and even anthrax meningitis. So the death of his target is not unexpected, especially given the consideration that the victim is likely to have multiple daily exposures every time they shaved.

Why is the shaving brush a clever idea? Well, firstly it’s an object that is likely to be used very regularly, and the spores will survive a very long time upon it. Secondly, not only will it be used often, the likelihood is that it will come into contact with broken skin sooner or later, increasing the chances that severe infection will occur. Third, the inoculation event will be temporarily distinct from the infection, with days to weeks separating the contamination of the brush and the presentation of the infection, making it very hard to trace back to an individual or time point. Finally, and probably most cleverly, these kinds of shaving brushes were often made of badger or boar bristles. During the Great War, however, there was a large scale cutaneous anthrax outbreak linked to shaving brushes that were made of untreated horsehair, some of which were mocked up to look like more expensive badger. This means even if someone identified the shaving brush as the cause, they would have reason to believe that it was an unintentional exposure and there would be even less likelihood of connecting it to our suspect.

Having succeeded once, like many murderers, our suspect decided to try again. The wife of his first victim, yes the one he was having an affair with, appears to become a little too much now her husband is no longer in the picture. He uses the cover of a routine typhoid injection (which had been available as required since the 1897) prior to a trip abroad to inject her with an infectious agent that resulted in her death. It doesn’t list what but if direct injection is an option, and no antibiotic exist, the world is your oyster in terms of bacterial choice.

This may feel a little far fetched, but the video below includes information about the way genetic evidence was collected to show that a doctor within the US injected his ex girlfriend with HIV under the cover of it being a vitamin B injection in order to infect her. Sometimes reality is even stranger than fiction.

Murder is Easy

This is one of my favourite Christie books, and I think it is one that is less known to many. It also has one of my favourite microbial deaths, this time of a main character. Under interrogation it would not be possible for me to deny that all these facts are connected. Luke Fitzwilliam, our detective character and a retired colonial police officer, meets Miss Lavinia Pinkerton on a train to London who is planning on visiting Scotland Yard. She confides in him that a serial killer is operating in her quiet English village, Wychwood-under-Ashe, and that the deaths have been disguised as ordinary accidents. She names a number of deaths that have already occurred (Amy Gibbs, Tommy Pierce, and Harry Carter) and says that the local doctor, Dr. John Humbleby, will be next. I do think this is why I don’t speak to strangers on trains.

Luke mostly thinks that Lavinia just has an over active imagination, until he sees in the newspaper the next day that Miss Pinkerton has been killed in a hit-and-run accident in London. As a result he travels to Wychwood-under-Ashe to investigate further.

He finds that the 3 deaths he’s been told about have occurred in a wide number of ways:

  • Amy Gibbs: Died after drinking hat paint swapped with her cough mixture bottle
  • Tommy Pierce: Pushed from a high windowsill (while cleaning) to his death
  • Harry Carter: Pushed off a footbridge into the river, where he drowned

Dr. Humbleby then dies under suspicious circumstances of sudden onset septicaemia (blood stream infection), but how does it happen? Although anthrax is cool, this method is even cooler. So let’s talk pus.

Dr Humbleby dies as a result of our killer accidentally-on purpose injuring him with scissors whilst he visits their home. When dressing the injured hand our killer uses a bandage that they have deliberately contaminated with pus discharging from the ear of an infected cat, named Wonky Pooh.

Pus is not just fluid; it is a dense mixture of dead white blood cells, cellular debris, and often billions of microorganisms, frequently from different species, combined in one sample. The act of introducing pus (even a small amount) has an infection rate of close to 100% (although obviously no trials on this) as it will overwhelm local tissue defenses, frequently leading to localised tissue damage, and delayed healing. As we are talking about the pre-antibiotic era here, systemic infection (i.e. infection impacting blood or organs) is very likely to occur as the local wound infection cannot be treated. It means our killer has a very high chance of fulfilling their deadly objective. I personally love a pus sample as they are such great specimens to work with…I don’t know what that says about me.

The Mirror Crack’d From Side to Side

Although I have only found three deaths directly linked to microbes, Agatha Christie didn’t just use microbes for murder, she also used them as the motivation for murder.

There is no avoiding spoiling this one I’m afraid, so skip this section if you don’t want to know the core of the plot

The story starts out with film star Marina Gregg and her husband, film producer Jason Rudd, moving into Gossington Hall (the same Hall that features in the Body in the Library) in the village home of Miss Jane Marple, St Mary Mead. The stylish couple host the local village fête where a deadly encounter occurs.

One of the local villagers, Heather Badcock, meets Marina and as part of their discussion talks about how many years before in Barbados she had left her sick bed in order to get an autograph from her. Heather later dies of poisoning at the same event. Miss Jane Marple is not well and so is at home and misses both the conversation and the death, but when more people start to die she decides to investigate and find the reason behind Heather’s death.

As she speaks to people she gets many different explanations as to the reason that Heather was sick when she went to collect the autograph, everything from Chickenpox to Flu. Miss Marple works as an infection detective as the causative organism is what the entire motive hangs on. Eventually, she manages to get an accurate recounting of the conversation from the Vicar, who tell her that Heather says she had German Measles. This fits with what others have said, in that she covered her face with powder in order to hide her rash.

First, let’s talk about what German Measles is, as it is not actually a name in common scientific use, and hasn’t been the approved name since 1881. The virus in question is rubella, but when the presentation was originally discovered it was known as German Measles because it was first described as being distinct from measles by German physicians. Prior to this presentation recognition, rubella was considered to be a variant of either measles or scarlet fever. In 1740, the German physician and chemist Friedrich Hoffmann recognised that it was, in fact, a separate infection. The name rubella was given by surgeon Henry Veale in 1866, meaning little red, as a way to more accurately describe the rash and was widely adopted in 1881.

Why does it matter that Miss Marple identified rubella as the cause? In healthy adults rubella presents as a rash with small flat spots and a high temperature, with or without joint pain and cold like symptoms. You are infectious for ~1 week before the rash starts and 1 week afterwards. Infection is usually mild and self resolves in a week to 10 days. So why would this conversation with Marina result in Heather’s death?

Well, it turns out that Marina had been desperate to have children, so desperate she had adopted. She finally found herself pregnant, but in a way she had never understood, she discovered she had caught rubella when she was 4 months pregnant. As a result, her child was born with a severe congenital learning disability and was placed in a special care facility from birth. Marina suffered a nervous breakdown and became reliant on medication as a result. When Heather approaches her, for the first time ever Marina knows precisely where she was infected and by whom.

Far from being a mild disease in pregnant women, infection, especially early in pregnancy can have devastating consequences for the foetus. For this reason in the 1970s the rubella vaccination programme was introduced. I remember all the girls in my class being walked into a room separate from the boys when I was in primary school to get vaccinated. The aim of this selective program was specifically to target pre-pubertal schoolgirls and non-immune women of childbearing age in order to protect future pregnancies from the risk of Congenital Rubella Syndrome (CRS).

You may have noticed, however, that the virus infects all individuals, and so by only vaccinating those physiologically capable of bearing children the transmission chain is not interrupted, only the consequences of infection. For this reason the vaccine, within the UK, was extended to everyone in 1988 in order to support better transmission control.

Global vaccine introduction was driven by an outbreak across Europe and the US between 1962 – 1965 that impacted over 12.5 million people in the US alone, and resulted in 11,000 miscarriages and stillbirths. The Mirror Cracked came out in 1962, and so the audience would have been very sensitive to the plot lines within, especially as there was no way to protect pregnancies at the time. Heather deciding to ignore her symptoms and deliberately risk exposing others would have been a particularly heinous act, I image, and there is a powerful quote associated with it as the end of the book:

Heather Badcock meant no harm. She never did mean harm, but there is no doubt that people like Heather Badcock (and like my old friend Alison Wilde), are capable of doing a lot of harm because they lack – not kindness, they have kindness – but any real consideration for the way their actions may affect other people. She thought always of what an action meant to her, never sparing a thought to what it might mean to somebody else.
Agatha Christie, The Mirror Crack’d From Side to Side

I feel that is a strong reflection on some of the more modern behaviours that we see in response to infectious disease, especially post pandemic, and the way vaccine related behaviours are starting to impact wider society. Not only are vaccines beneficial to individuals, but they protect the wider community, not all of whom can get vaccinated. By protecting ourselves we protect others, an option that wasn’t available for Marina, but is available to all of us.

The every present impact of infectious disease

Infectious diseases were part of every day life for most of the time that Christie was writing, and for most of it responding with antibiotics was also not an option. In The Mirror Crack’d, Doctor Haydock says he has to continue his rounds as he has 8 cases of German Measles, Whooping Cough, and Scarlet Fever that he needs to see. Numbers that would be shocking today in a small English village, two thirds of which are now vaccine preventable, and the other readily treated with antibiotics. I think because we don’t see the negative consequences of these types of infection in our every day life, outside of healthcare, we don’t realise how fortunate we are to live in an age where we have such options.

As well as being background, some infectious diseases, especially polio, even provided an alibi…as well as a setting up scenarios for becoming a target for murder in her books.

Christie wrote books at the height of the global polio epidemics and the resulting disease is used as a realistic backdrop to shape the characters’ temperaments, physical mobility, or alibis. Polio is a virus that causes everything from asymptomatic infections to life-threatening paralysis, and nowadays is another vaccine preventable infection.

Before modern ventilators became available, patients who experienced muscle weakness due to polio infection were sometimes managed within iron lung machines, that were used to mechanically assist or if needed take over the work of breathing for a patient who has lost control of their respiratory muscles. Having seen historic examples of these when I worked at Boston Children’s Hospital, I can testify to how terrifying they must have been if your child ended up in one.

Within the book, the Crooked House, which came out in 1949, one the main characters is a boy of 16 who is recovering from a mild case of polio. He has a lot of residual stiffness that causes his grandfather to pull him out of school and provide him with a private tutor instead. He becomes isolated by being at home, and the presence of the tutor is also a big driver in the plot after his grandfather is found dead. Polio, therefore, drives a number of the circumstances that result in the subsequent deaths.

Another book that some people may be less familiar with is called Ordeal by Innocence that was published in 1958. The matriarch of the Argyle family is found murdered and one of her adopted children is found guilty, is sent to jail, and subsequently dies.

Dr. Arthur Calgary is a geophysicist who returns from a two year expedition to the antarctic. He sees coverage of the case and realises he is the alibi for the son Jacko who was convicted, but he could not testify as he was away. He turns up to inform the family of the son’s innocence and sets in motion a series of events that reveal the real killer, but also results in many more deaths.

It also causes Philip Durrant, who is married to one of the other Argyle children, to begin his own investigation. Philip has recently contracted a case of severe polio that has left him paralysed and confined to a wheelchair. He hates being dependent and commences his own investigation as a way of asserting his independence. It may not end well for him.

Finally, and I’ve saved one of the best for last. I’m talking about The Pale Horse released in 1961. Some people don’t love this one, but I have to tell you I find it brilliant and clever, and so atmospheric I adore it. I won’t talk about how the deaths are achieved in this one as it is too fun to spoil, but I will mention that one of the main suspects is known as Mr Venables, who requires the use of wheelchair after severe polio infection. An eye witness identifies him close to a crime scene, but his legs are entirely atrophied, making it physically impossible for him to stand or walk. A lot of the discussion therefore centers around whether his has a genuine polio disability or is it a long in the planning elaborate alibi. I’ll leave discovering the answer to you.

Agatha Christie used the times in which she lived, not just as the backdrop for her novels, but as the driver for the plots within them. It is no surprise, therefore, that infectious diseases featured heavily. Living in a pre-antimicrobial, mostly pre-vaccination world must have been terrifying, especially if a loved one fell ill. Using that fear of the unknown, fear of the less understood, makes a lot of sense when setting the scene for murder and mayhem. The inclusion of a detective character, whose job it is to reduce the chaos and make the world make more sense, also explains why it may have struck a cord with those reading who also were experiencing disease within their own daily lives. This deep dive has just made me extra grateful for all the progress we have made in making these organisms much more present in books than they are in my reality, and if possible love Christie even more than I did before.

All opinions in this blog are my own

And now…for a shameless plug

If you love Halloween, or a nice outbreak thriller/zombie film, keep an eye out for my new book ‘Don’t Open That Door: A microbiologist’s guide to infection in movies and TV’ is out in early December, and available for kindle pre order now:

Have you ever wondered whether The Last of Us TV series could actually happen?

Have you ever considered what you would do if you were the one standing at the air lock door in Alien?

Would you open it or leave your crew outside in order to save humanity?

If you’ve ever watched a blockbuster and thought, “Wait, is that how infections actually work?”

Then this book was written for you.

In Don’t Open That Door! A Microbiologist’s Guide to Infection in Movies and TV, Professor Elaine Cloutman-Green (affectionately known to her fans as ‘The Girlymicrobiologist’) bridges the gap between Hollywood fiction and real-world science. Drawing on over two decades of experience as an NHS Consultant Clinical Scientist and infection control expert, she takes you on a fascinating, approachable journey through your favourite movies and TV shows to reveal where the storytelling ends and the real science begins, helping you find the fact within the fiction.

What’s Inside:

  • The Survival Basics: Master the fundamentals of microbiology and infection control, including how pathogens spread from airborne droplets to zoonotic transmission.
  • The Intervention Arsenal: Learn the truth behind pandemic interventions, exploring everything from real-world isolation protocols to the mechanics of vaccines.
  • The Rogue’s Gallery of Pathogens: Dive into dedicated sections exploring the distinct worlds of viruses, fungi, parasites, and bacteria.
  • Hollywood vs. The Lab: Deep-dive into chapters exploring both your favourite cult films and TV series, as well as ones you may be less familiar with. Discover how fictional world-building and cinematic outbreaks stack up against actual scientific investigations.

Whether you are a die-hard sci-fi geek, a horror movie buff, or simply curious about the microscopic partners that share our world, this book will completely change the way you watch television.

Happy Halloween

Celebrating the Hospital Detectives: Why I describe Infection Prevention and Control as the detectives within our healthcare drama

girlymicro General, Microbiology (Clinical), Science Communication , , , , , , , , , , , , ,

This weekend I’m off to Torquay for the Agatha Christie Spring Literary Festival. It will involve talks, a statue unveiling and even a ball! Some of you will know that I’m a massive Agatha Christie fan and love a good murder mystery. It’s part of the reason my ambition for when I retire is to finally have time to write some of the pathology murder mysteries that I have drafted out. I’m planning a three book series called The Murder Manuals. Anyway, that’s some way off but I still love to indulge in a bit of Agatha joy.

Whilst thinking about it this weekend, when I should have really been packing instead, it occurred to me that maybe one of the reasons that I love my job so much is because, in many ways, working in Infection Prevention and Control (IPC) is like working to solve real life mysteries and challenges on a daily basis. You come into work every day not really knowing what the future will hold and spend your days trying to uncover who the criminals (microorganisms) are and how to prevent future ‘crimes’, in the form of infections. This feels even more true having recently posted about how a forensic science lecture I went to looked at solving crimes. So, whilst my head is all linked to the detective process (I suspect I’m more Miss Marple than Hercule Poirot, although really I’d love Mr Girlymicro and I to be Tommy and Tuppence) I thought I would write about why I believe IPC professionals make the best healthcare detectives.

Beginning at the end

Like most good crime dramas, we in IPC, often make our entrance towards the end of a story when we things have already happened. We then have to work backwards to understand what’s happened as well as working forward to prevent any future risk (‘crimes’). Now, the point we get involved can range a bit. Just like in detective dramas, if the crime is obvious the police get involved early. Sometimes however, Miss Marple suspects a crime has occurred (think Sleeping Murder) but everyone else can be slow to get onboard.

In the world of IPC sometimes there are very clear events that need to be looked into. An outbreak for instance is traditionally described as 2 cases linked in person, place and time, or a single case of a significant infection, such as Ebola. This works pretty well most of the time but there are circumstances where using this definition can mean it takes you longer to identify an outbreak, or ‘crime’, has occurred. An example of this is when outbreaks are linked to an intermediate environmental source. This means that you may have low level numbers of cases which don’t appear to be linked in time, or even person, but are just linked to location. I’ve written about the importance of environmental IPC before, but this is one of the reasons it can be particularly tricky.

Need to understand the rules

In every detective story there are rules. If you’re in a Christie novel there will be a denouement, if you’re watching Columbo you will always see the murder at the start, and if the murderer is a female she will always be the person Morse tries to flirt with badly at least once. Infection Prevention and Control is no different. There are unwritten rules that you need to learn and which will help guide you on your way. Vancomycin Resistant Enterococci outbreaks will often have an environmental component. Norovirus outbreaks within staff often have a secret staff member who vomited in the toilet and told nobody. Pseudomonas aeruginosa outbreaks make people ask ‘have you checked your water?’ All of these things give you a way to start investigating and a set of questions to begin with.

Now, here comes the word of warning. Just like The Murder of Roger Ackroyd broke the rules, so do bacteria and other outbreak causes not always behave the way they are supposed to. Just like any good police drama with a rebellious detective, you need to know the rules but also know when to ignore them. Know when to switch tack and think that your MRSA outbreak may actually be linked to your ventilation system, not direct hand to patient transmission. Be neutral enough when looking at your data to not ignore the clues that are there. Red herrings will be present and distract you, so know when to call a fish a fish.

Start broad and narrow down

One of the best ways, with any investigation, is to start broad and narrow down. This enables you to avoid diving down rabbit holes and missing other pathways that should be investigated. Very rarely can you turn up to a country house murder and exclude most of those present, and as Hercule Poirot famously states “it is always wise to suspect everybody”, and the same is true with IPC investigations.

Ask yourself, why do I think that there’s something happening? How do I know that cases occurring at the same time are actually linked? How are my surveillance systems set up to support identification of low levels of cases over prolonged periods? How sure am I then that a ‘crime’ has actually been committed? Once the body as been found, in terms of looking for sources, where do I get my information from? Do I consider just other patients, or patients and families, or patients, families and the environment, or even patients, families, environment and staff. This, all before you even start to consider how different organisms behave in different types of patients. In a country house murder you need to consider those above stairs as well as those below, and in stories like the A.B.C. Murders, you even need to consider those who came and rang your doorbell.

There are so many moving parts within healthcare and we need to ensure that we are capturing as much of that landscape as possible when we start our investigations. Starting broad supports this, but you also then need to know the key moments to start excluding options so that you can eventually get to the depth needed to support interventions and change. Eventually you have to have the scene where you commit and name the murderer. Within IPC, events such as outbreak meetings can really help with this, as unlike our favourite detectives, we can’t keep all the information to ourselves right to the very end. These meetings bring people together to both help gathering information but also to decide on how to focus next steps.

A plethora of unreliable witnesses

In A Murder is Announced Miss Marple states, ‘Please don’t be too prejudiced against the poor thing because she’s a liar. I do really believe that, like so many liars, there is a real substratum of truth behind her lies’. One of the things that is often quite difficult to pin down during IPC investigations is….what is the truth? Truth is often seen as definitive but in reality truth relates back to the lens through which the individual sees the world. For instance, if you asked me what I was doing at 7am last Wednesday I wouldn’t lie, but I would have to offer some form supposition as I can’t actually remember precisely. The other complication is that those directly involved may be even less able to recall their own roles. If I’m sick in hospital days can merge into one and I’m focussed on my physical reality rather than taking in my environment. This is all before we take into consideration the fact that we may be providing sedatives and other medications that could impact recall. Would I remember that one of my visitors mentioned my niece had diarrhoea……..probably not.

Within IPC investigations no one is likely to remember every physical action, which is why audit can be a helpful addition, in order to have an external person capture trends. In other scenarios the actual witnesses to the event can’t speak, for instance ventilation gauges that may have fluctuated or alarmed (is that a voice?) to an event that no one wrote down or reported. This is especially challenging when you are trying to get to the bottom of grumbling outbreaks that have been going for some time, but also is a particular challenge linked to infections with organisms that may not become apparent for months, such as some surgical site infections or infections with pathogens like Aspergillus. Memory can make individuals particularly poor witnesses in these scenarios and good record keeping and notes are essential to support look back investigations (investigations where you are looking back to capture risks and event detail).

Need to know which tools to use

If you only interview half of the witnesses in your case, you’ll be lucky to get even half of the story, as it will all depend on which people hold the information. On some occasions you will luck onto all the answers with the first witness, but is this a risk you want to take? The same can be true in IPC investigations if you don’t think about the tools or sampling methods you want to access from your toolkit. Is your main focus on using bacterial culture? Do you have a method that will work even if the patient is on antibiotics? If you are looking for a viral cause, what method is best? PCR is not PCR is not PCR. You can look for RNA, or DNA, you can extract from different volumes and different types of samples. The pros and cons of all of which need to be considered. Putting together a sampling strategy in response to an investigation is like choosing the pieces of a jigsaw puzzle whilst knowing that you are not going to have all of the bits. You want to choose pieces that give you the best chance of accurately guessing what the picture is.

In IPC there are various pieces of documentation that will help with thinking in this area. Documents like the UK Standards for Microbiology Investigations (UK SMIs) can help guide thinking linked to which samples might be useful to take. UKHSA also has various documentation linked to outbreak investigation with specific organisms and interpretation criteria, such as measles, C auris, and TB. At the end of the day however, just like your detective walking into a murder scene, you will need to work out how to apply that guidance to what you see in front of you.

It’s all about the clues

Once you have investigated and questioned your witnesses then you need to be able to work out from your clues which pieces are useful and which are your red herrings and may lead you astray. Like all investigations the most important thing is to be methodical but you then need to make time to be able to think and reflect. Poirot famously once solved a case without leaving his front room, just by being able to sit and question those involved. I’m not saying that this is something we should try in terms of IPC, but I do think it holds some lessons for us about the power of thinking time. Especially when you are in the midst of an outbreak there is often a real drive to be seen to be doing something, responding to everything, and constantly doing more. After 20 odd years in micro/IPC I think I’m beginning to think that Poirot may have been onto something.

If you are constantly changing or adding in responses it can be really difficult, even if you reach resolution, to know which thing you did made the difference. Early on in an outbreak it can be easy to rush into making recommendations prior to having gathered all the information you need. It sometimes feels good to call an exposure meeting the minute you get the information that an event has happened. For instance, you may have days to respond in the case of something like a chickenpox (incubation period 8 – 21 days), before those patients become a risk to anyone else. Therefore waiting to call a meeting until you have gathered all the clues, until you know everyone’s immune status, levels of exposure etc, can mean that your meeting is so much more effective in managing any risk. Waiting until you have a decent action plan for where you might search for clues, i.e. sample, may mean you find the answer so much more quickly then having to go in for multiple attempts. Taking a breath and putting thought before action may mean you get to the final result so much faster. So utilise those Little Grey Cells!

Not everyone takes kindly to be investigated

IPC should not be about blame, but just like the house guests in a country house murder may not take kindly to a visit from Inspector Japp, some occupants of your ward may be less than happy to see IPC walking up to the nurses station. Although I talk about the similarities between IPC and detectives, we should not be feared and act like police,  or worse than that judiciary. Often the reason why Jessica Fletcher gets further faster in finding the murder than the police at the scene is because she is seen as just another friendly visitor rather than someone looking to find fault. Her focus is on building and utilising relationships in order to gather information. She is often seen by the other witnesses involved as being part of their team, and the outputs of her investigations are often linked to co-production of outcomes by sharing information, rather than going it alone.

In general, as in many areas of working life, relationship building is key. You see Jessica all the time in Cabot Cove, not just when there’s been a murder. That means that by the time she finds the body she already knows most of the players and has built up relationship capital with those involved. This enables her to sometimes ask the challenging questions. I believe the same needs to be true for IPC. If clinical teams only see us when things go wrong, they are automatically going to be somewhat defensive. If they see and work with us when times are going well, as well as less well, they are more likely to feel we’re in it together with shared ownership. All of which means we may also get to the source that much faster when we need to.

Sometimes there’s a twist in the tail

There are a number of famous Agatha Christie stories where the murder victim turns out to not actually be dead, I won’t spoil them here. The same can be true for IPC cases. There are certain organisms, of which Adenovirus is my personal favourite, that can both cause primary infection and then go latent and reactivate later. Often this reactivation is linked to immune status, and of course many patients in hospital have immune systems that are doing less well. These present challenges as you can look like you have a cluster of cases but, due to the type of patient, they can all be independent findings that happen to cluster together. So, without the right investigations you can call ‘murder’ when actually there is no corpse. Being happy to hold your hands up and step down when you have new information is an important trait, but knowing to get the testing done to enable you to do so is even more so.

The other scenario that can happen is, as Sherlock Holmes famously said, “When you have eliminated the impossible, whatever remains, however improbable, must be the truth“. There will be things that have been done, behaviour that has occured, that you would never imagine or predict. Over the years I’ve found a lizard in a bathtub, olive oil used as skin care by parents, and all kinds of things in fridges and freezers, just as the tip of this iceberg. Things that out in the real world would probably not be a risk, but in the healthcare world can lead to all kinds of issues, none of which would be on my primary list of questions when trying to identify a source. The world continues to surprise me, and therefore in the world of IPC keeping enough of an open mind to to respond to the unexpected is essential.

It’s a team sport

Poirot has Hastings. Morse has Lewis. Sherlock has Watson. Tuppence has Tommy, and Jessica has most of the population of Cabot Cove. Solving crimes benefits from teamwork and IPC is no different. I’ve spoken about the importance of relationship building but doing IPC investigations well benefits from more than even that. One of the key ways these partnerships work is by creating the space where the discussion and reflection we’ve already talked about can happen. In healthcare, which is far from a contained setting with only a handful of key players, being part of a team can also provide vastly more eyes and insight into what happens in reality.

The Hawthorne effect is a type of human behaviour reactivity in which individuals modify an aspect of their behaviour in response to their awareness of being observed

One of the reasons that it’s important to undertake a team response within IPC is that if I turn up, a stranger or less frequent visitor on the ward, then those on the unit may behave differently because I’m there. If you see IPC hanging around a sink, for instance, then you may suddenly focus way more on your hand hygiene efficacy then you would otherwise. If I go to speak to a family, they may say different things to me than they would to the bed space nurse they see everyday. In order to get the full picture I may not always be the right person to ask the questions. Being fully integrated, being seen as part of the team, or having relationships with people that are, can make all the difference in terms of the success of your activity. Everyone benefits from having a Hastings to send in to ask questions from time to time.

No greater satisfaction than being part of the denouement

I don’t know about you but I just love the moment that everyone gathers at the end of a Christie novel and detective starts the process of walking everyone through all of the different clues, red herrings, and witness statements. The moment when you discover if you’ve picked up on everything that was on offer to you, and even more than that, the anticipating of waiting to hear if you’ve put it all together in a way that a) works and was b) actually correct.

I feel the same way when I finally have that moment when I crack the case, when I find the source, or even just get to the point where I understand a tricky result. The hallelujah moment when you look down at the jigsaw pieces you have and you can finally see the full picture. It’s the reason that some of our favourite investigative successes live on for years in  teaching and case studies. I will talk about the case of the Norovirus and Biscuit Tin to anyone who will listen even now. The settings may be different but every detective, whether in a novel or in healthcare, loves to regale others with their exploits. We just can’t help ourselves. My excuse is that sharing the learning helps is all. That said I’m off to attend a talk called ‘How to kill people for profit’. I’m assuming it will give me all the tips I need to be the next cozy murder success and maybe even weave in the odd IPC detective drama moment into the mix. 

All opinions in this blog are my own