Microbe INVASION! FINAL PROGRAM SCRIPT Audio/Narration /MUSIC, EFFECTS We live in a microbial world. Every day we’re exposed to billions of invading
bacteria and other microscopic creatures. But after years of trying to exterminate or exclude them,
scientists now realise many of them are allies, not enemies. Some are so
essential to us, we should consider them as a vital human organ. Scientists
argue that instead of waging war on bugs, in many cases we should welcome … the Microbe Invasion. For three and a half billion years Earth has been
ruled by bacteria. iThey have colonised every corner of the planet…and
its occupants. As far as they and other microscopic creatures are
concerned, the human body is simply another virgin territory to invade and
occupy. “We have emerged as a species on a planet
that’s predominated by microbes. Microbes have learned over the course of
millions of years of very stringent selection how to insinuate themselves onto
and into their mammalian partners.” So far we’ve treated microbes more like enemies
than partners, defending ourselves against attack with antibiotics and
vaccines. But in the war against disease, scientists are
discovering many bacteria actually fight on our side. By studying their strategies and weapons we can learn
from our microscopic allies “ They should be viewed as our teachers. They
have been forced to devise a whole range of means of manipulating the biology
of their hosts in a way that benefit the microbes but do not harm their hosts.” For every microbug that causes disease, there are
hundreds more that do no harm at all. Some are even our best line of defence against death
and disease. Scientists now believe that by understanding the
complex partnership between our bodies and their billions of microbes, we may
be better equipped to fight deadly infections. “They have developed strategies for manipulating
our genes and by turning to them we should be able to forge new ways of
manipulating our biology to promote health and to prevent disease.” Just like the earth itself, our body is a living
planet, a network of ecosystems where bacteria are the dominant life form.
There’s only one time in our lives when it isn’t so. While it’s in the womb, this baby lives in a
sterile cocoon, protected from an invading army of bacteria and other bugs. ii For Sarah Tregonning, this is her fourth baby,
but it’s still a miraculous and slightly scary experience. /Lightning and Thunder FX/ /Natsot/ Birth noises/ This is the moment everyone has been waiting for: the
baby, his mother, his father, and the combined forces of the microbe invasion. The first offensive takes place in the birth canal.
iii For generations, occupying armies of bacteria have
lived on Sarah and now, they’re ready to invade this new world and all
its terrain. [PAUSE] As the baby emerges from the womb and begins to slide
past the birth canal walls, the first tiny microbes leave his mother and attach
to the baby’s skin. The invasion has begun. Billions of microbial competitors join in. They land,
dig in, and secure a beachhead wherever they can. While some of these invaders are our enemies, many
will become our closest allies. At this vulnerable stage of life, a baby needs all the
protection he can get. Dangerous microbes could win the battle for territory
and take his life in a matter of hours. But even as this child takes his first breath, a
second invasion has begun. This second wave of microbes launches itself as soon
as the baby emerges Hundreds of competing species race to take up a
strategic position on the baby’s body. Some are potentially harmful. All of them are common in every mother’s
intestines. iv /NATSOT/“It’s a wee boy..it’s a wee
boy…” Most bugs will be marooned on the baby’s skin
and die there; but some will make it into his mouth and be swallowed. Eventually they’ll occupy his intestines /NATSOT/“You’ve got a grandson. “And his name is?” “Alexander Charles” “Oh isn’t that nice?” If he doesn’t pick them up at birth,
there’ll be plenty more chances in the days and weeks after. Touching,
kissing and even spitting on him, everyone he meets will cover him in bugs. v But these bacteria are a precious gift: an army that
will defend this baby throughout his life. Bugs like Lactobacilli secrete acid
onto our inner surfaces, which discourages other, more harmful bacteria from
settling there. vi Bifidobacteria are another ally. Inside the
baby’s intestines, they reproduce quickly and protect him from bad
bacteria, simply by overcrowding them. vii So it’s actually a good idea to welcome some of
these microscopic invaders. Scientists believe our body may even encourage
bacteria with nutrient signposts, just before or after birth. “These signposts consist of nutrients, nutrients
that are manufactured by the cells that line our intestine. Now an early
colonizing species of micro-organism is able to use these signposts to set up
shop in a particular location of the intestine and can use these nutrients as
important food sources.” Breast-feeding positively encourages helpful bacteria.
Mother’s milk contains antibodies that specifically target harmful
microbes. But it allows helpful species like Bifidobacteria to thrive. viii It’s a telling example of our close partnership
with many types of bacteria. As Sarah’s child grows, all of his available
territory - inside and out, will be conquered by microbes. By the age of two, he’ll be occupied by many
different species of bacteria. He will never be alone. In fact, like all of us
- his cells will be vastly outnumbered by the microbes. “The total number of microbes that colonise our
surfaces exceed the total number of cells in our body by at least a factor of
ten. We are more microbial than we are Homo sapiens.” ix Our entire lives are spent in partnership with
friendly bacteria. They have evolved so closely with us that we can even
consider them part of our own family. But other microbes aren’t so committed to that
relationship. There are plenty of opportunists out there, ready to take what they
can from us and move on. Whether we live or die matters little to them. So we and our microbial allies, have evolved some
sophisticated weapons to protect our vulnerable territory. BREAK ONE Act 2 The mouth is an open door to microscopic opportunists. Every day, we and our microbial partners have to guard
against disease causing organisms like salmonella that enter here. x The constant supply of food, warmth and moisture, make
our mouth an ideal home for billions of microbes. Swarms of bacteria like spirochetes live in this rich
sea of saliva, and so do their giant predators. Protozoans like Trichomonas prey on them as well as
dead skin cells and scraps of food. xi Music and fx When human populations boom in a confined area, they create
elaborate structures and societies we call cities. The same thing happens in our mouth, only it’s
called a biofilm. xii Using our teeth as foundations, Streptococcal bacteria
stick themselves to the enamel surface. They and billions of others build
blocks and towers as busy and crowded as any modern metropolis. 50 The longer it grows, the more complex life in the
biofilm becomes. But just like a human city, these dense populations
can produce pollution. Some bacteria create the sulphur compounds responsible
for bad breath. xiii Others feed on sugars, and excrete acid powerful
enough to strip the enamel off our teeth. xiv There’s a good reason why brushing and flossing
stops these bugs from damaging our teeth and gums. The action tears down the protective biofilm, and lets
in fresh air. Many of the bacteria living here are anaerobic; for them oxygen
is a lethal poison. As the biofilm collapses, so does their world. While Streptococci are the dominant bacteria in this
oral society they come in many species, most of them friendly. “In your mouth, you have massive populations of
these friendly streptococci but they’re not there to harm us, in fact
they’re our closest friends. They’re our own if you like personal
army of protectors, there to defend us against the occasional rogue
streptococcus” Professor John Tagg knows all about rogue strep. As a
child, he was plagued with streptococcal infections that gave him sore throats
and rheumatic fever – a disease that kills five hundred thousand people
every year xv. John Tagg survived but it left him with a burning ambition “ I was quite determined then to get one back on
the streptococcus” “It became a lifetime obsession” It took thirty years of research, but Professor Tagg,
of New Zealand’s Otago University
has made a major discovery. Not only are some strains of Strep harmless, at least
one produces its own natural antibiotic, known as BLIS. “BLIS is the little term that we’ve
developed if you like for this smart weaponry that bacteria seem universally to
apply to deal with the competitors that they will encounter in nature.” The good Strep use BLIS to sabotage the growth of
their competitors. BLIS are chemical weapons that target rival groups of
fast growing Strep bacteria. These micro-missiles penetrate the surface of the
enemy cells allowing vital nutrients to leak out. And so, an entire community
of competitors starves to death. By understanding how this biological control system
works, the BLIS research team are developing a natural alternative to
antibiotics. Trials so far suggest that giving children helpful
strep in a tablet establishes populations of these good bacteria in the mouth. The good bugs then go into battle to keep the bad bugs
under control. As a result, the chances of getting strep infections
are significantly reduced. As Dr. Tagg sees it –it’s smarter and more
economical to adopt nature’s sophisticated weaponry instead of blasting
the body with broad-spectrum antibiotics. “BLIS are the equivalent of the laser-guided
weaponry being developed today to take out specific targets. Rather than the
somewhat more crude approach of dropping an atomic bomb and taking out all the
terrain as well as the inhabitants.” Working with friendly bugs to discourage certain harmful
microbes in the mouth and throat is a clever idea. Meanwhile other
micro-organisms are swallowed and find themselves on a one way trip through the
human gut. The digestive system offers a rich array of habitats
for good bugs and bad. This is where we and our microbial partners work hard to
keep treacherous opportunists under control. The first line of defense is the stomach. This half-gallon pool of enzymes and hydrochloric acid
is enough to tear most microbes to pieces. But it’s not foolproof. For years scientists assumed that the stomach was
sterile but they have now discovered that some bacteria actually make their
home in this liquid hellhole. Helicobacter pylori live in the stomach lining. They
create their own chemical shield to protect themselves from stomach acid. xvi “Helicobacter pylori is a spiral shaped
bacterium that sets up shop in half the humans that live on this planet. For
most humans this organism colonises the intestine, produces a short-term
inflammation of the lining in the intestine, but then enjoys a relatively
– what we think – a relatively innocent relationship with its
host.” But for 20 per cent of people with this bacteria xvii,
the benign relationship turns nasty. The immune system tries to attack these
spiral-shaped bugs. Instead of killing the bacteria, however, the powerful
chemicals damage the stomach lining, causing painful ulcers. Other microbes can make it past the stomach safely,
provided they know a trick or two. Salmonella is the most common food poisoning bug. It
often crops up in badly prepared meat or dairy products. xviii These foods contain fat globules that offer bacteria a
protective coating against stomach acids. And so, Salmonella slip past our defenses in a kind of
Trojan horse made of grease. But the body does have a means of fighting back
against these aggressive marauders: ..its own fat-busting detergent called bile. Bile is like dishwashing liquid – it breaks up
fat into tinier globules we can absorb. It also happens to be lethal to many
kinds of bacteria. xix However, some microbes survive these perils in
protective coats or spores. They head for the small intestine - a rich feeding
ground for friendly microbes and opportunists. But bacteria have a hard time
settling down here. They must fight against the churning rapids of
liquidised food and digestive juices. Any creature that wants to stick around
here has to be specially equipped. xx The only ones that are, are real monsters. Tapeworms are the ultimate parasites, superbly adapted
for life in the human gut. xxi Some species grow to almost fifteen feet long. Others
can reach more than thirty feet. xxii Some species grow to more than 4 metres long. Others can reach over nine metres Such monsters can block the intestine, or consume so
much food their hosts suffer malnutrition. They reproduce by detaching egg sacs that pass through
the intestine to be picked up by another unsuspecting host. xxiii These parasites feed while latched on to the
intestinal lining with a bunch of hooks and suckers attached to their ugly
heads. 21 Most bacteria get swept harmlessly downstream along
with the food. But one tough customer will always cause havoc - given
half a chance. Clostridium enters the gut in its own protective
spore. Once activated, it becomes a protein feeder. xxiv It digests the meat in the diet, but it can also make
a meal of our intestinal lining. Victims can end up with deadly abdominal
infections. xxv To stop these bacteria and their toxic waste products
from damaging our tissues, every week or two we shed the layer of cells that
lines our intestine. xxvi “These cells sit at the interface between a
toxic wasteland and the rest of the body and their renewal probably is part of
an ancient mechanism designed to take away damaged cells as a result of their
exposure to the toxins that exist in the diet.” The shed cells make a feast for bacteria like
Clostridium, and they’re welcome to it. But down at the bottom of our intestinal folds,
budding young cells are vulnerable to attack. Recently scientists discovered
the powerful defence system that protects them. xxvii Paneth cells are like anti-aircaft batteries. They
launch packets of destructive enzymes that protect the cell
“nursery” from bacterial attack. For microbes that have survived this far, the
hazardous journey is almost over. After travelling 20 feet ( six metres)
through the small intestine they are about to reach the promised land –
the colon. xxviii This is where bacterial numbers explode and where the
partnership between our bodies and our bacteria truly flourishes. We rely so
heavily on our friendly bugs that many scientists now consider them as vital as
any human organ. “We have a kilogram and a half of bacteria in
our gut which constitutes an organ, an organ that is as important to our
physiology as our lungs or our kidneys or our liver. And this organ does things
like helping it to digest food, it provides a lot of vitamins, it breaks down a
lot of drugs, it provides various essential lipids and precursor molecules, so
it is very much a part of our physiology…we are partly bacterial.” BREAK 2 ACT III What we choose to consume affects our health. But just
as important is the mounting recognition that our health also depends on the
colonies of bacteria that live in our intestines. From her teenage years, Sarah Tregonning suffered
terrible digestive problems. She had flatulence, bloating and stomach cramps. “Sometimes I’d be constipated and other
times I’d be having dreadful, dreadful diarrhoea, and I had no idea of
when that would be or what foods would set me off.” Sarah was put on high fibre diets and treated with
steroids but nothing really worked. Eventually she was diagnosed with irritable
bowel syndrome - a chronic illness that affects up to 25 per cent of the
population, mostly women. xxix “When I first started working I had problems
with irritable bowel syndrome and it was really difficult because I was working
in the food industry and you can’t just keep running off to the toilet
every two minutes when you desperately need to go and there’s nothing you
can do to control it.” /Audio tape / “I got to the stage where I was so thin because
of the constant diarrhoea and the constant pain in my stomach was preventing me
from eating because anything I ate would still upset my stomach.” The causes of irritable bowel syndrome are not clear
but most of the symptoms are associated with the colon. We mightn’t think of our colon as the land of
milk and honey but for trillions of bacteria – this is heaven. And it’s here that science is uncovering an
extraordinary relationship between humans and microbes. This is where the bacterial population explodes
– fuelled by fibre. Our bacterial allies break down what’s left of
our food – the roughage we can’t digest. xxx In the process, they create waste products, mainly in
the form of gas. xxxi The gas may be a discomfort but it’s a fair
trade for the extra nutrients we get from the bacterial activity. All in all,
it makes for a mutually beneficial relationship. “We’ve come to an arrangement, with our
gut flora, and we provide a home for them, we provide a surface for them to
live on, the mucosal surface and they provide the nutrient and they provide the
protection.” In such ideal conditions, everyone jostles for a prime
position. The good bacteria expand quickly to fill the space
available. Fortunately for us, that helps keep harmful bugs away from our colon
walls. “So our normal bacterial flora provide a major
barrier to any new organisms that would like to come and live in our gut and
that applies of course to poisoning organisms like salmonella and things, that
might wander down there. They’re the first defense against invading
species.” To protect their patch, friendly bacteria like
Lactobacilli produce acid that discourages harmful microbes from breeding.
xxxii As bad bacteria reproduce and grow they often give
themselves away by broadcasting toxins into the area. Our friendly bugs listen for such enemy broadcasts, as
well as communicating among themselves. xxxiii “One thing that’s becoming quite clear, is
that there is a lot of molecular chattering going on, not only between the
bacteria themselves, but also between the bacteria and our own cells.” This constant chit-chat gives bacteria a good idea of
their own numbers and the number of possible enemies too. If our bacterial allies decide there are too many bad
bugs in the neighbourhood, they’ll attack them with their own biochemical
weapons. But the body’s defence force, the immune system
is “listening in” too. If it detects a mounting threat of
insurrection, it’s always ready to enforce the peace. xxxiv But when there are too many bad bugs, the immune
system just evacuates the area. We experience this as vomiting or a bad case of the
runs. “It just throws everything out the nearest
way. If the damage is being done in the stomach then up it comes. If it’s
being done in the colon then down it goes and if it’s in between it can
go both ways.” But there is a drawback to this drastic evacuation.
Our empty spaces become ripe for colonisation by harmful species. The same
thing can happen after taking antibiotics. “Broad spectrum antibiotics affect the normal
healthy flora of the bowel. And a not infrequent problem in people taking
antibiotics is of course they develop diarrhoea – because some of the
good bacteria die off and the bad ones start to grow up and produce
toxins.” /Sound fx/ Luckily, we can repopulate our intestines with good
bacteria from the supermarket shelf. Yoghurt and other live-bacterial products, known as
probiotics are proving to be life-changing health supplements. xxxv After 15 years of chronic pain and discomfort, Sarah
Tregonning chanced upon a solution to her problems. One day she walked into a
health food store and got talking to natural therapist Georgie Chisholm. The therapist recommended Sarah take a daily dose of
live bacteria. She thought these good bugs might just help. Sarah was ready to try anything – even
swallowing capsules of live bacteria. After 3 months, Sarah’s irritable bowel settled
down. “I don’t have the constant urge to go to
the toilet. I don’t have the dreadful bloating or the stomach cramps and
I can eat not quite whatever I fancy but certainly I can eat with a lot more
comfort than I used to. It is a miracle cure and it’s literally cleaning
me up from the inside out.” Probiotics - the idea that taking live bacteria might
be beneficial to human health is only now beginning to gather scientific
support. “The scientific community were very sceptical
about this at first – the major claims for the benefits of probiotics, I
think, are really that they stimulate the immune system and secondly that they
strengthen this barrier of resistance to invading bacteria and therefore they
would help to protect you against food poisoning, infectious diarrhoea and help
improve your gut after you’d had an episode.” But it now seems scientific evidence and backing for
probiotics is taking off. When Russian cosmonauts developed digestive problems
during long missions in space, medical staff developed a special yoghurt to
settle their stomachs. xxxvi They cultured bacteria from the intestines of
crewmembers who were doing fine and fed it to the troubled cosmonauts. By eating yoghurt containing their comrades’
bacteria, the cosmonauts’ troubled digestions were happily fixed. Commercial voice: “…it’s culture at
the highest level” What to do with astronauts’ intestinal bacterial
is an issue that’s troubled NASA since the sixties. It’s a matter
of volume and weight. “There are trillions of bacteria in our colon,
and when we defecate each day half the mass of our stool are live bacteria that
emanate from this microbial society.” The last thing Nasa wanted on their spacecraft were
waste units full of live bacteria. So they devised foods intended to shut down the
astronauts’ gut dwelling bacteria altogether. “When the Americans wanted to put a man on the
moon, they had to get around this problem of defecation. They designed this
special diet which was totally residue free, there was nothing for the gut
bacteria to feed on, and so the idea was that the gut bacteria effectively
died. They could go for three or four weeks without defecating. When the time
come it was an agonizing experience. But, they could go for three or four
weeks, they could do a moonshot.” But the idea never took off. Astronauts would have
nothing to do with the special diet. Without bacteria colonising our “Inner
Space” we’d all be in deep trouble. But if we allow bacteria into our forbidden zones, the
consequences can be dire. Third Break Act IV The outer surface of an adult human offers around
twenty square feet ( 2 square metres) xxxviiof skin. For microbes there’s a wide choice of climates
and habitats. With little sweat or other secretions, our legs are
like dry deserts. Here there are about 70,000 microorganisms per square inch.
xxxviii 11,000 microorganisms per square centimetre There are even more in the forest of the scalp. But the steamy jungles of the armpits and groin
support the densest populations of microbes. Up to six and a half million
bacteria occupy every square inch. Up to one million bacteria occupy every square
centimetre. With its oily secretions, the face is microbe paradise. By the end of a typical day, the bacterial population
here is exploding well into the millions. xxxix Clostridium spores constantly settle on our skin. In
the right conditions, they can become flesh-eaters. To protect ourselves from
these bacterial infestations.. ..we simply move them on. Dead skin cells detach in
small clustersxl……taking any hitch-hikers with them. If bad bugs do get in, they can inflict terrible
damage. Mark Inglis is one of New Zealand’s most successful
wine-makers – but it wasn’t his first career choice. He used to be
a mountaineer until he lost both legs at the age of 22. While climbing Mt Cook, New Zealand’s highest
mountain, Mark and a fellow mountaineer became trapped by bad weather. It was
fourteen days before they could be rescued. They were lucky to be alive but by
then frostbite had set in to their feet. “ I always remember on the way to the hospital
Phil and I discussing that we’d perhaps lose the big toe; at the worst
perhaps we’d lose all of our toes. You know there’s plenty of
climbers around missing toes. We didn’t even consider the thought of
gangrene or the extent of the frost bite, losing whole legs.” In the hospital, Mark’s feet were slowly thawed
out but the damage was done. “Every day in hospital, the feet swelled up and
then started to discolor and then started to turn black.” Frostbite had turned the water in his body cells to
ice, rupturing the cell walls and killing the tissue. The destruction opened the way for bacterial infection
by Enterobacter xli, causing gangrene. “With the wet gangrene, they puffed right up,
first one foot, then the other. Then after treatment with antibiotics, the foot
almost mummified.” In the end, surgeons had no choice but to amputate. On
Christmas eve 1982, Mark Inglis had both legs removed just below the knee. “Nothing can ever prepare you to waking up and
seeing the sheets end so much shorter on your bed. Those were the worst three
days of my life.” Keeping bacteria out of the body’s forbidden
zones requires constant vigilance. Dead or damaged tissue is just one way in for rogue
bacteria, but the body has other access points that it must defend. The eyes and ears are protected by a powerful
antibacterial compound called lysozyme. Earwax collects trespassers like flypaper. And then
lysozyme molecules home in on their captive targets. xlii These antibacterial molecules attack by chopping bits
out of the invaders’ cell walls. xliii Airborne microbes like Clostridium are trapped and
killed here every day, but there are billions more floating in the air. And so we have a series of clever traps for dealing
with them. In the nostrils, giant hairs and sticky surfaces catch
some invaders. xliv But others manage to slip past these defences. /Music and FX/ If a dangerous intruder like a Clostridium spore
infiltrates the lungs, then bodyguards called macrophages arrive swiftly to
deal with them. xlv /FX/ The Macrophage engulfs the invader… and removes
it for disposal Millions of tiny hairs on the walls of our airways
carry unwelcome bugs back up towards the throat. xlvi Once there, we either drop them into the acid bath of
our stomach by swallowing, or eject the bugs back into the air with a cough.
xlvii Every minute of the day these traps prevent microbes
from invading our forbidden zones. At the same time, in places where
they’re welcome, we tolerate our microbes as part of a healthy ecosystem. But what happens to the microbes when we die? The latest scientific research reveals there is indeed
life after death. FOURTH BREAK ACT V There is one final journey that we and our microbes
will take together. The journey to death, and beyond. When we die, our bodies are prepared for burial or
cremation. While such respect is quite natural, it interferes with the
processes of Nature. In this unusual outdoor laboratory, people have
donated their bodies so that forensic scientists can uncover the secrets of
natural decomposition. (SOUND ON TAPE)L.W. ..at this point in time” Dr. Richard Jantz and his team of anthropologists from
the University of Tennessee study the process of decay - to help criminal
investigators identify the time and cause of death. xlviii “Bacterial proliferation in the body is
pretty active and a lot of bacteria grow, so, they’re working from inside
out. And then with the warmer weather the flies become more active and lay
eggs, so you’ll have a larger maggot population and they work form the
outside in; so, they’re efficient soft tissue carnivores. So
they’ll go relatively quickly – three and a half, four
weeks.” While insects play their part in dismantling the body,
the forensic scientists are uncovering the hidden role performed by microbes. “Even in the absence of insects, the body will
putrefy and eventually decompose. So the decomposition process sort of starts
from the inside out, and the body’s own microbes consume it, so to
speak.” Some of our decomposers may even be descendants of the
bacteria our mothers handed down to us at birth. Many of them have helped keep us alive and healthy
since the day we were born. Now, without the living ecosystem we provide, they
face the end too. As the skin cools and dries out, it becomes an
inhospitable place for most bacteria. xlix While the body is alive, the soldiers of the immune
system fight to keep rogues like Clostridium out of sensitive areas. But now the immune system is out of action. l Without macrophages to keep them under control, vast
numbers of Clostridium spores hatch out and rampage through the body. Caught up in a feeding frenzy, the expanding
population’s activity raises the temperature to over 120 degrees
fahrenheit. li (over 50 degrees celsius) As the last supper continues, the feasting hordes
create large amounts of gas. With all the exits closed, it has nowhere to go. The body begins to bloat as the bacterial party goes
out of control. lii But the contents of the intestine are soon used up. “There are some bacteria which just live off
carbohydrates and fibre and that’s it, they don’t have anything to
eat they’re done for.” Starving and overwhelmed by the protein eaters, our
allies begin to die. “There are other bacteria which can digest
protein very happily and they’ll start digesting you.” Clostridium and other decomposers finally serve as our
undertakers, breaking down our organs and tissues. As they see us into our
afterlife, they’re also planning their own. Clostridium produces spores for when the party ends.
In these time capsules, they can travel freely and reactivate.. …centuries later. liii About five to ten days after death, the skin bursts.
In a flash, billions of partying microbes die when they are suddenly exposed to
oxygen and cold temperatures. liv Those that have prepared for this moment will escape
on a breeze, or perhaps on the body of a feeding insect. lv The rest will die and break down as our flesh dries
out and is eaten by scavengers. Only the skeleton will endure, and we’ll
be alone, for the first time since we left the womb. For most of our lives, we’ll be unaware of our
body’s inhabitants and the battles they fight for us. Good or bad, they can’t live without us, and
we’d be in trouble without many of them. From the moment we’re born, our good bugs will
dig in and become our first line of defence. “ We acquire these partners from the beginning
of our life as we enter this world. We live with them and we die with them. And
the question that I think is so exciting is to decipher the significance of
this microbial partnership to our own biology, how microbes shape and participate
in shaping our physiology and how that contributes to our health and how that
sets us up for vulnerabilities or resistances to a variety of different
diseases” No matter where life takes us, we’ll never be
alone. We’ll always be accompanied by our microbial allies, the armies of
the microbe invasion. /Theme Music to end/ /SFX OVER LOGO/ i “Australian rocks 3,485 million years old
contain eleven or more types of rcognisable fossil bacteria. The oldest rocks
on Earth thus contain vestiges of life.” Margulis, L. and Sagan D. 1995.
What is Life? Simon & Schuster, p.53. Madigan M.T., Martinko J.M. and Parker J. 2000. Brock,
Biology of Microorganisms. Ninth edition. Prentice-Hall International Editions,
p.424. ii Tannock, G.W. 1995. Normal Microflora.
Chapham&Hall, p.37. iii Tannock, G.W. 1995. Normal Microflora.
Chapham&Hall, p.37. iv “At the moment of birth or shortly
thereafter, microbes in faeces that have been expelled involuntarily by the
mother during labour…have the opportunity to colonize the neonate.”
Tannock, G.W. 1995. Normal Microflora. Chapham&Hall, p.37. v “Suckling, kissing and caressing of the infant
after birth provide additional insurance that members of the microflora are
transmitted from one generation to the next.” Tannock, G.W. 1995. Normal
Microflora. Chapham&Hall, p.37. vi “Lactobacilli are often found in dairy
products, and some strains are used in the preparation of fermented milk
products….The lactobacilli are rarely ever pathoghenic.” (p.506-7).
Madigan M.T., Martinko, J.M and J. Parker 2000. Biology of Microorganisms.
Prentice-Hall International Editions. “…these aerotolerant rods produce lactic
acid from simple carbohydrates. The acidity inhibits competing bacteria, but
lactobacilli grow well in acidic environments. In humans, lactobacilli are
located in the vagina, intestinal tract, and oral cavity.” (p.287)
Tortora, G.J., Berdell, R.F. and C.L. Case 1992. Microbiology. An introduction.
The Benjamin/Cummings Publishing Co. Inc vii The study referenced here shows the probiotic
effect of bifidobacteria by direct inhibition of the adherence of pathogenic
bacteria. (Bernet MF, Brassart D, Neeser JR, Servin AL. (1993) Adhesion of
human bifidobacterial strains to cultured human intestinal epithelial cells and
inhibition of enteropathogen-cell interactions. Appl Environ Microbiol;
59(12):4121-8). viii Tannock, G.W. 1995. Normal Microflora.
Chapham&Hall, p.44. Hill, J.M., Path, F.R.C., and Marsh, P.D. 1987. Human
Microbial Ecology. CRC Press, p 92. ix This microbial collection, generally referred to as
the normal microflora, is acquired soon after birth. It is estimated to consist
of about 1014 microbial cells, outnumbering the approximately 1013 human cells
that make up the body.” (p.1) Tannock, G.W. 1995. Normal Microflora.
Chapham&Hall. x “One important biological property of the
outer membrane layer of many gram-negatve Bacteria is that it is frequently
toxic to animals. Gram-negative Bacteria that are pathogenic for humans and
other mammals inlude members of the genera Salmonella, Shigella, and
Escherichia, among others.” Madigan M.T., Martinko J.M. and Parker J.
2000. Brock, Biology of Microorganisms. Ninth edition. Prentice-Hall
International Editions, p.74. xi http://www.homepages.uel.ac. Lange, D.E, Stockmann, H., and Hoecker, K.,
“Vorkommen und Identifizierung von Protozoen in der menschlichen
Mundhoehle”, Dtsch. Zahnaerztl. Z., 38, 906, 1983. [Presence and
identification of protozoans in the human mouth] xii Spake A. Taking aim at the citadels of slime “In the same way that organisms that everyone is
familiar with birds or coral reefs or what have you…form very complex
communities complex both physically and biologically- bacteria do the same
thing…so biofilms can be a few species or many many species moreover the
physical structure can be very complex – just like the physical structure
of a coral reef or a rainforest is very complex. In a biofilm you get
towers of cells in this extracellular matrix and channels and bits coming off
that move further down into the biofilm. A metaphor people have used is cities
…and if you can imagine cities as having office blocks and smaller
buildings and roads and alleys then that is not a bad analogy.” Transcript taken from UB136 – Biosignal
00:11:22:00: xiii
http://www.abc.net.au/rn/ xiv Prof. John Tagg during a telephone conversation on
the 25 May 2001 (paraphrased):” Lactic acid is produced by the organisms that
colonise the teeth, like streptococci. It is the most powerful organic acid. It
is able to break down the enamel in the teeth.” xv Of over 15 million deaths due to circulatory
diseases, 7.2 million were caused by coronary heart disease, 4.6 million by
stroke, 500 000 by rheumatic fever and rheumatic heart disease, and 3 million
by other forms of heart disease. http://www.who.int/whr/1997/ xvi “H pylori is unique in its ability to thrive
in the human stomach. It does this by activating its own cytoplasmic urease,
which converts urea into carbon dioxide and ammonia. The ammonia first
neutralises the gastric acid that enters the outer membrane of the bacteria,
preventing acidification at the inner membrane. This allows the bacteria to colonise
the stomach” Berger, A. Scientists discover how helicobacter survives
gastric acid. BMJ 2000;320:268 ( 29 January ) xvii % of population H Pylori positive: 66% % of ulcers related to H Pylori: 85% (from CDC website) % of those who are H Pylori positive and who get
ulcers = 21%, (or 7x the number who are H Pylori negative) http://www.jr2.ox.ac.uk/ xviii “All salmonellae are considered pathogenic
to some degree, causing salmonellosis or Salmonella Gastroenteritis”
Tortora, G.J., Berdell, R.F. and C.L. Case 1992. Microbiology. An introduction.
The Benjamin/Cummings Publishing Co.Inc. p.624. “Meat products are particularly susceptible to
contamination by Salmonella. If these products are mishandled, the bacteria can
grow to infective numbers rather quickly. The sources of the bacteria are the
intestinal tracts of many animals, and meat can be contaminated readily in
processing plants. Poultry, eggs, and egg products are often
contaminated.” Tortora, G.J., Berdell, R.F. and C.L. Case 1992.
Microbiology. An introduction. The Benjamin/Cummings Publishing Co.Inc. p.624. xix “Bile is a potent selective agent since,
while most bacterial species are killed by relatively small concentrations of
bile acids, some are resistant and some species…are stimulated by the
presence of bile.” Hill, J.M., Path, F.R.C., and Marsh, P.D. 1987. Human
Microbial Ecology. CRC Press. p.63 Neufeld, F., Ueber eine specifische bacteriologische
Wirkung der Galle, Z. Hyg. Infektionskr., 34, 454, 1900. [About a specific
bactericidal function of bile] xx “Bacteria in the upper small intestine are
exposed to high concentrations of bile salts, proteolytic enzymes…The
rapid flow of fluid through the small bowel and the flushing effect of the
small bowel secretions assist in maintaining small bowel cleanliness and the
resting small bowel is only heavily colonized in conditions of stasis. Hill,
J.M., Path, F.R.C., and Marsh, P.D. 1987. Human Microbial Ecology. CRC
Press. p.72. xxi “The head, or scolex, has suckers for
attaching to the intestinal mucosa of the host. Some species also have small
hooks for attaching to the host. Tapeworms do not ingest the tissues of their
hosts; in fact, they completely lack a digestive system. To obtain nutrients
from the small intestine, they absorb food through their cuticle.”
(p.320-1) Tortora, G.J., Berdell, R.F. and C.L. Case 1992. Microbiology. An
introduction. The Benjamin/Cummings Publishing Co.Inc xxiv In table 13.28 (p.510) C.[lostridium] sporogenes,
C. tetani, C. botulinum, C.tetanomorphum and C. propionicum are listed as amino
acid fermenters. Madigan M.T., Martinko J.M. and Parker J. 2000. Brock, Biology
of Microorganisms. Ninth edition. Prentice-Hall International Editions xxv “Clostridium difficile is a major cause of
antibiotic-associated diarrhea. While treatment regimens for C. difficile have
been available for decades, they remain less than optimal due to the frequent
recurrences that occur after therapy is completed. Moreover, the morbidity and
expense associated with C. difficile have underscored the need for more
effective preventive measures than are currently available.” Ciesla
WP, Bobak DA. Management and Prevention of Clostridium difficile-Associated
Diarrhea. Curr Infect Dis Rep 2001 Apr;3(2):109-115 “Clostridium difficile causes 300 000 to 3 000
000 cases of diarrhea and colitis in the United States every year.”
Mylonakis E, Ryan ET, Calderwood SB. Clostridium difficile--Associated
diarrhea: A review. Arch Intern Med 2001 Feb 26;161(4):525-33 xxvi “..crypts are the principal sites of cell
regeneration, replacing cells which migrate up the epithelial escalator. The
epithelium is renewed in approximately 3-5 days. At villus tips senescent cells
are shed.” (p.297) Mims, C., Nash A., and Stephen J. 2001. Mim’s
patogenesis of infectious disease. Academic Press. San Diego xxvii “Paneth cells live in the bottom of
microscopic pits -- called crypts -- in the lining of the intestinal wall. The
crypts create new cells that line the intestinal wall; this wall of cells is
replaced every four to six days and is the only barrier between the bloodstream
and bacteria ingested with food. Paneth cells are like sentinels that protect
this cell renewal process from bacterial infestation by forming a chemical
barrier of immunity.” xxviii “In most animals, the length of the small
intestine is roughly 3.5 times body length - your small intestine, or that of a
large dog, is about 6 meters [20 feet] in length.” Colorado State University;
Hypertext for biomedical sciences xxix Irritable bowel syndrome: an update on
therapeutic modalities. : Expert Opin Investig Drugs 2001 Jul;10(7):1211-22 Farhadi A, Bruninga K, Fields J, Keshavarzian A. Department of Internal Medicine (Division of Digestive
Disease), Pharmacology, Molecular Biophysics and Physiology, Rush University
Medical Center,
Chicago IL,
USA. “Irritable bowel syndrome (IBS) is the most
common condition that a physician faces in the GI clinic. Of the general population,
10 - 25% suffer from symptoms judged to be IBS. The negative impact of this
disease includes not only pain, suffering and direct medical expenses but also
significant social and job-related consequences.” Irritable bowel syndrome in women: the
physician-patient relationship evolving. J Am Osteopath Assoc 2001 Dec;101(12
Suppl Pt 2):S12-6 Foxx-Orenstein AE, Clarida JC. Department of Gastroenterology, Medical
College of Virginia,
Virginia Commonwealth
University, Richmond 23298,
USA. aefoxx@hsc.vcu.edu “Irritable bowel syndrome (IBS) is one of
the most common functional gastrointestinal disorders seen by primary care
physicians and specialists. The disorder affects approximately 15% to 20% of
the world's population and is predominately found in women.” xxx “Your body thinks it has taken everything
that is any good out of the food and all that goes down into the colon is just
rubbish that’s unusable. And the bacteria use that rubbish to so good
effect that 30% of the weight of the content is just pure bacteria. The
bacteria are shoulder to shoulder you know, they are really tightly packed in
there and they just multiply and multiply and multiply. And they have broken
down the fibre, and when they break down the fibre you get about 10% or more of
the energy.” Prof Michael Hill, Southbank
University, London during interview on 13 Sept. 2000.
UB9 0:12:44 xxxi “Some foods which are poorly absorbed in
the stomach and intestines can be metabolized by fermentative bacteria
resulting in the production of hydrogen and carbon dioxide. In many
individuals, methanogenic bacteria then convert some of the H2 and CO2 to
methane gas (CH4).” (p.395) Brock, T.D. and Madigan M.T. 1991. Biology of
Microorganisms. Sixth edition. Prentice-Hall International Editions xxxii “…studies with antibiotic treated
animals suggest that the flora protects individuals from pathogens.
Investigators have used streptomycin to reduce the normal flora and have then
infected animals with streptomycin-resistant Salmonella. Normally, about 106
organisms are needed to establish a gastrointestinal infection, but in
streptomycin-treated animals whose flora is altered, fewer than 10 organisms
were needed to cause infectious disease. Further studies suggested that
fermentation products (acetic and butyric acids) produced by the normal flora
inhibited Salmonella growth in the gastrointestinal tract.” xxxiii :” Bacterial communication, toxin
production tied to intriguing cell Protein”. Weidenbach, K., Stanford University.
xxxiv Telford G, Wheeler D, Williams P, Tomkins PT,
Appleby P, Sewell H, Stewart GS, Bycroft BW, Pritchard DI. The Pseudomonas
aeruginosa quorum-sensing signal molecule N-(3-oxododecanoyl)-L- xxxv “Probiotics [Greek pro, for, and bios,
life], the oral administration of either living microorganisms or substances to
promote health and growth, has the potential to reestablish the natural balance
and return the host to normal health and nutrition.” p.558. Prescott,
Lansing M., John P. Harvey and Donald A. Klein, 1996. Microbiology. WCB
Publisher xxxvi BBC World News 12 August 1999: New Scientist from 14 August 1999 reported the same
story: xxxvii An average human adult has about two m2 [21.5
feet2] of skin surface, containing a variety of different
microenvironments…” Brock, T.D. and Madigan M.T. 1991. Biology of
Microorganisms. Sixth edition. Prentice-Hall International Editions. “The skin … constitutes 10% of the total
bodyweight and in an adult has an area of approximately 1.8 square metres [19.4
feet2].” Marples, M.J. 1965. The ecology of the human skin. Charles C.
Thomas, Publisher [Researcher’s note: This makes 20 feet2 a good
intermediate.] xxxviii “The figures go something like this (per
cm2) [per inch2] for a grown man: 1 million [6,500,000] in the armpit, 1.5
million on the scalp, 200.000 [1,300,000] on the forehead, but only 50.000 per
cm2 on the back and 11.000 [71,500] on the forearm.” (p.58) Andrews, M.L.A.1976.
The Life that lives on Man. Faber & Faber, London. [Researcher’s note: We
considered the environment of the forearm and the leg as very similar, thus
interchangeable] xxxix Bacterial count on face. (p. 200) Bodanis, D.
1986. The Secret house. Simon
& Schuster,
New York xl “About 10.000 million [10 billion] skin
scales or squames peel off each of our bodies every 24 hrs.” (p.166)
Andrews, M.L.A.1976. The Life that lives on Man. Faber & Faber, London xli The enterobacteria family includes numerous
inter-related genera, all of which are microscopically indistinguishable.
The group includes E coli and Salmonella species ref: Bacteriology Illustrated,
Gillies & Dodds His medical records state that Mark Inglis grew
Enterobacter & some E coli from his feet. 1 swab post amputation grew
Staph epidermidis. Some Enterobacter are normal gut commensals, others
are normally present in the environment, However they may also be
pathogens. They are the most common cause of intra-abdominal infection
and urinary tract infection, especially post surgery. xlii Petrakis NL, Doherty M, Lee RE, Smith SC,
Page NL: Demonstration of lysozyme and immunoglobulins in human cerumen.
Clinical and genetic implications. Nature 229: 119-120, 1971 xliii “Lysozyme is an enzyme that cleaves
glycosidic linkages in peptidoglycan in the bacterial cell wall, leadening zu
weakening of the wall and cell lysis.” (p.777). Madigan M.T., Martinko
J.M. and Parker J. 2000. Brock, Biology of Microorganisms. Ninth edition. Prentice-Hall
International Editions. xliv “The normal microbiota of the nose is found
just inside the nares. Staphylococcus aureus and S. epidermidis are the
predominant bacteria present and are found in approximately the same numbers as
on the skin of the face….The upper and lower respiratory tracts (trachea,
bronchi, bronchioles, alveoli) do not have a normal microbiota.” (p.556)
“Microorganisms larger than 10?m are usually trapped by hairs and cilia
lining the nasal cavity.” (p.575) Prescott,
Lansing M.,
John P. Harvey and Donald A. Klein, 1996. Microbiology. WCB Publisher xlv “If microorganisms actually reach the lungs,
then certain phagocytic cells – the alveolar macrophages, or dust cells
– usually locate, ingest, and destroy most of them.” (p.590)
Tortora, G.J., Berdell, R.F. and C.L. Case 1992. Microbiology. An introduction.
The Benjamin/Cummings Publishing Co.Inc xlvi “The mucociliary blanket of the respiratory
epithelium traps microorganisms less then 10 ?m in diameter that are deposited
on the mucosal surface and transports them by ciliary action away from the
lungs.” (p.575) Prescott, Lansing M., John P. Harvey
and Donald A. Klein, 1996. Microbiology. WCB Publisher xlvii This so-called ciliary escalator keeps the
mucous blanket moving toward the throat at a rate of 1 to 3 cm per hour;
coughing and sneezing speed up the escalator.” (p.409) Tortora, G.J.,
Berdell, R.F. and C.L. Case 1992. Microbiology. An introduction. The
Benjamin/Cummings Publishing Co.Inc. xlix Most fungi are classified as saprophytes because
they live on dead or dying material and obtain energy by breaking down organic
matter in dead plants and animals. Trautmann N., and Olynciw, E. Compost
microorganisms. l “White blood cells move about for at least six
hours [after death].” Mims C., 1998. When we die. Robinson, London. P.113-120 li “The metabolic changes caused by maggots and
anaerobic bacteria cause the internal temperature of the carcass to rise up to
53?C [127?F].” Goff, M. Lee, 2000. A fly for the prosecution; How insect
evidence helps solve crimes. Harvard University Press, Cambridge,
Massachusetts; London, England lii The abdomen shows signs of inflation as result of
putrefaction. As by-product of the metabolic activity of anaerobic bacteria
that invade the body from the guts gasses are produced. Mims points out that
“…at this stage, reached in temperate countries four to six days
after death, there will be a disagreeable odour due to release of the gases
hydrogen sulphide and methane, and traces of mercaptans. The smell of a
decomposing body is remarkably persistent and penetrating.” (p. 121) Mims
C., 1998. When we die. Robinson, London liii “A number of gram-positive bacteria can
form a special resistant, dormant structure called an endospore. Endospores
develop within vegetative bacterial cells of several genera: Bacillus and
Clostridium (rods), Sporosarcina (cocci), and others….. These structures
[endospores] are extraordinarily resistant to environmental stresses like heat,
ultraviolet radiation, chemical disinfectants, and desiccation. In fact, some
endospores have remained viable for well over 500 years…” Prescott,
Lansing M., John P. Harvey and Donald A. Klein, 1996. Microbiology. WCB
Publisher, p.67 liv The combined feeding frenzy of maggots and
anaerobic bacteria finally leads to breaking the skin, allowing the gasses to
escape and the corpse to deflate….[and] the corpse’s temperature
returns back to the temperature of the surroundings. By the end of the decay
stage only 20% or less by weight of the body remain, consisting mainly of bones
and skin. (days 5-11) Goff, M. Lee, 2000. A fly for the prosecution; How insect
evidence helps solve crimes. Harvard University Press, Cambridge,
Massachusetts; London, England lv As Dr Brian Batson (Southern Institute of
Technology, Invercargill, NZ) pointed out to me during a phone conversation on
the 26 April 2001 (paraphrased): “Even when an organism is not able to
survive on the decomposing body anymore, not only spore forming organisms have
a chance of survival. For instance the many visiting insects may take up
droplets of body liquids containing huge amounts of anaerobic bacteria and drop
them on your sandwich.”