Case Studies...
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Bacillus Cereus, Cereals and Rice
Bacillus cereus contaminates rice and other foods, leading to severe but short-lived food poisoning....
Bacteria and Evolution
Bacteria are ancient simple organisms that have evolved over millions of years. Some may be the ancestors of chloroplasts and mitochondria, cell organelles present in plant and animal cells....
Bacteria and Food Hygiene
It is relatively easy to achieve good food hygiene using some basic rules to reduce bacterial contamination. These can, quite literally, mean the difference between life and death....
Bacteria and Sex
Sexual contact results in millions of bacteria being exchanged between partners. Most of these are harmless but some are pathogenic and the diseases they cause can be serious....
Bacteria and Tooth Decay
Tooth decay has been a human problem since Neolithic times. Bacteria that live on the sugars in the mouth produce acid that erodes tooth enamel causing caries....
Bacteria in the Home
Most bacteria in the home are harmless but a few areas are danger spots. It makes sense to observe some hygiene rules in bathrooms, toilets, kitchens and around bins....
Bacteria That Deal With Pollution
Species of bacteria with an unusual collection of enzymes are able to break down complex toxic molecules that pollute the land and groundwater, rendering them harmless....
Bacteria That Fix Nitrogen
Proteins are vital for the growth of plants and animals and the nitrogen they contain comes mainly from atmospheric nitrogen that is captured by specialised nitrogen-fixing bacteria....
Bacteria That Infect Plants
About a hundred different species of bacteria infect plant and cause serious disease, usually by blocking internal transport vessels to cause wilt and rot....
Bacteria That Recycle Nutrients
Bacteria play a key role in the environment by recycling nutrients containing the elements nitrogen and carbon. Without such activity, these elements would be in short supply....
Bacteria, Boils and Spots
Many people, especially teenagers, get spots. Spots are hair follicles that become blocked with sebum and then infected by bacteria. Plants also get spot diseases that are caused by bacteria....
Bacterial Vaginosis: An Embarrassing Problem
Bacterial vaginosis is a common problem that affects 10-15% of women during their childbearing years. It causes vaginal discharge that has an offensive, fishy smell....
Dealing With Antibiotic Resistance
Antibiotic resistance is a global phenomenon and needs several strategies to try to limit its further development and spread....
Do Bacteria Cause the Common Cold?
It is often thought that the common cold is a bacterial infection but it is actually caused by different viruses. Bacteria do, however, have a part to play....
Do People Still Get Leprosy?
Leprosy is an active disease that is still present in about 120 countries, including the USA and Europe. At least 250,000 people currently have leprosy....
Do People Still Get the Plague?
The bacterium that causes the plague is still very much alive and waves of infection continued to affect other parts of the world outside Europe, causing isolated outbreaks and a few deaths....
E. Coli Food Poisoning
E. coli food poisoning is caused by toxin producing strains such as 0157, which causes a serious and potentially fatal disease....
Eye Witness Account: The Misery of Cholera
The cholera outbreak in Zimbabwe began in August 2008. In January 2009, when we interviewed Mwana, a student who had recently visited her family there, nearly 3000 people had already died....
Facts and Figures About MRSA
MRSA, a strain of Staphylococcus aureus that can resist treatment by many antibiotics is a serious problem in hospitals all over the world....
Facts and Figures About Vaccines
We already have some vaccines against bacterial diseases that help save thousands of lives worldwide. Research is ongoing to produce more vaccines against others such as cholera, TB and pneumonia....
Flesh Eating Bacteria
Flesh eating bacteria is used to describe the bacteria that cause necrotizing fasciitis, a very rare bacterial infection of muscle and underlying tissue that is caused by Staphylococcus pyogenes....
Friendly Bacteria in the Digestive System
There are trillions of friendly bacteria in the human digestive system. They carry out useful functions such as helping to digest plant material and vitamin production....
Friendly Bacteria on the Skin
Normal, healthy skin may have 180 different bacterial species living on it. These bacteria are described as friendly because they do no harm and they protect against potential pathogens....
H Pylori and Stomach Ulcers
Many stomach and duodenal ulcers are thought to be related to an infection by the bacterium Helicobacter pylori....
How and When Were Bacteria Discovered?
Bacteria were first seen in the 1660s, and proof of their link with disease was eventually obtained in the 1870s. Bacteriology has since become a science in its own right....
How Antibiotics Work
Antibiotics are either bactericidal (they kill bacterial cells directly) or they are bacteriostatic (they slow bacterial growth by preventing division). Individual antibiotics work by various chemical...
How Are Bacteria Classified?
Bacterial classification is one of the most rapidly evolving fields of science. Although bacteria are single-celled and relatively simple organisms, classifying them is a difficult and unfinished proc...
How Can People Catch Lyme Disease?
Lyme disease, a bacterial infection caused by the species Borrelia, is increasing in the US and Europe. Humans become infected through the bites of deer ticks or sheep ticks....
How Do Antibiotics Affect Friendly Gut Bacteria?
Antibiotics kill all bacteria in the body, affecting the friendly bacteria that live in the gut and on the skin, as well as the pathogenic bacteria causing the infection. This can lead to problems in ...
How Do Disinfectants and Antiseptics Work?
Disinfectants kill bacteria on the surface of non-living objects; antiseptics have the same purpose but are used on the surface of the skin of animals and people....
How Does Legionnaires Disease Spread?
Legionnaires disease is caused by the bacterium Legionella pneumophila, which is spread in fine droplets of water that circulate from the air conditioning systems of large buildings....
How Many Types of Bacteria Are There?
There are trillions of bacteria on Earth, but all can be grouped into a relatively small number of types. This classification aids recognition and understanding of bacteria....
I Got Food Poisoning from Rice: Case Study
Cooked rice that is refrigerated and made into dishes such as rice salad can be contaminated with the spores of Bacillus cereus. Short lasting but distressing food poisoning can then result....
I Got Hot Tub Folliculitis!
Hot tub folliculitis is an infection of the hair follicles caused by Pseudomonas aeruginosa, which thrives in the warm water of poorly maintained hot tubs....
I Nearly Died from Toxic Shock: Case Study
Jenny suffered a very rare and unusual infection of a contraceptive diaphragm and developed toxic shock syndrome....
Identification of Bacteria
Various long-established and modern techniques are used to detect which bacteria are present in an unknown sample, such as the blood of a dangerously ill patient....
Is it Possible to Develop New Antibiotics?
Some new antibiotics are in development, but the pace of research has slowed in recent years due to the relative unprofitability of antimicrobial drugs....
Is Tetanus the Same as Lock-jaw?
Tetanus, commonly known as lockjaw, is caused by an infection with the bacterium Clostridium tetani....
Listeria and the Dangers in Pregnancy
Listeria food poisoning is rare but serious. A quarter of all people who are severely affected die and it can cause miscarriage and early delivery in pregnant women....
Major Classes of Antibiotics
Antibiotics are divided into classes depending on their mode of action and what type of bacterial infections they treat. The major classes include penicillins, aminoglycosides, tetracyclins, cephalosp...
My Mum Died of C Difficile: Case Study
Sandra’s mother went into hospital for a routine operation. Although otherwise fit, Louisa succumbed to a fatal C difficile infection after being given a course of broad spectrum antibiotics....
My Stomach Ulcer Was Due to a Bug: Case Study
Reg’s digestive discomfort turned out to be a stomach ulcer but it surprised him to learn that this was due to a bacterial infection, not to stress....
People With Leprosy Still Live in Fear
Leprosy, an ancient disease, is caused by the bacterium Mycobacterium leprae. It affects many people in India who are often afraid to seek treatment because of the stigma that still surrounds the dise...
Q Fever: the World's Most Infectious Disease
Q fever can develop after infection with just one bacterium and causes either a flu-like illness, pneumonia or liver problems....
Salmonella Food Poisoning
Salmonella food poisoning is caused by eating food contaminated with Salmonella typhimurium or Salmonella enteritidis....
Shigella in the Developing World
Shigella causes dysentery, a severe food-borne illness that affects 165 million people in the developing world every year; over a million of them die of this infection....
Trachoma and Blindness
Trachoma is the world’s leading cause of infectious blindness. It takes the sight of millions of people in the developing world, many of them women and young children....
Tuberculosis, Past, Present and Future
Tuberculosis, TB, has killed billions of people throughout the history of humankind and is still infecting millions on the planet today....
Useful Bacteria in Food
Some foods are prepared intentionally to contain large amounts of useful bacteria. Lactobacillus and Bifidobacterium species are commonly used in probiotic foods and supplements....
Using Microscopes to See Bacteria
Several different microscopes can be used to view bacteria, from the simple light microscopes to incredibly sophisticated electron microscopes and scanning electron microscopes....
What Are Antibiotic Resistant Bacteria?
Antibiotic resistant bacteria are strains of bacteria that can carry on growing and dividing normally in the presence of an antibiotic that should kill them, or severely inhibit their growth....
What Are Antibiotics?
Antibiotics are drugs used to treat bacterial infections. They act specifically on bacteria, although some are also able to kill parasites. Antibiotics are not effective against viruses or viral infec...
What Are Bacteria?
Bacteria are tiny single-celled organisms. Millions of them live in and around us and there are thousands of different types. Friendly bacteria carry out useful functions, pathogenic bacteria cause di...
What Causes Scarlet Fever?
Scarlet fever, an infection caused by Streptococcus pyogenes, a Group A Streptococcus, is now easily treated with antibiotics but it used to be extremely serious....
What Health Conditions Do Klebsiella Bacteria Cause?
Klebsiella bacteria are not commonly known but they can cause serious infections; antibiotic overuse has created resistant strains that affect patients in hospitals....
What is a Strep Throat?
Strep throat is a severe, sudden onset of a sore throat caused by the bacterium Streptococcus pyogenes. It should be diagnosed and treated quickly to avoid serious complications....
What is Bacterial Meningitis?
Bacterial meningitis is a life threatening bacterial infection of the membrane and fluid that surrounds the brain and spinal cord....
What is Botulism?
Botulism is an illness caused by the effects of a potent toxin released by Clostridium botulinum. Infant botulism, food-borne botulism and wound botulism all cause nerve paralysis....
What is C Difficile?
C difficile bacteria live in the intestine of health adults and are normally harmless. It has become a major cause of hospital infections and diarrhoea in elderly patients treated with antibiotics....
What is Cellulitis?
Cellulitis is the medical term that is used to describe a serious infection within the tissues of the skin. It occurs when bacteria start to grow within connective tissue, causing swelling, redness an...
What is Cholera?
Cholera is a water-borne disease caused by the bacterium Vibrio cholerae. It causes severe, watery diarrhoea that can lead to lethal dehydration....
What is Gangrene?
Gangrene is a skin condition in which bacteria cause deep-seated infections. It can be the result of deep wounds, or can occur in tissues that have a poor blood supply....
What is Impetigo?
Impetigo is a skin infection cause by Staphylococci or Streptococci. It is usually not serious and clears up by itself, or with the help of antibiotic creams or, in severe cases, oral antibiotics....
What is Inside a Bacterial Cell?
Bacterial cells contain fluid cytoplasm that is surrounded by a rigid cell wall and a flexible cell membrane. The bacterial genome is the main internal feature....
What is MRSA?
MRSA is short for methicillin-resistant Staphylococcus aureus, a strain of bacteria that commonly causes hospital infections. MRSA is resistant to methicillin, penicillin and most other antibiotics in...
What is Otitis Media?
Otitis media is a bacterial infection that affects the middle ear. It is usually caused by Haemophilus influenzae or Streptococcus pneumoniae and follows an initial viral ear infection....
What is Psittacosis?
Psittacosis is a bacterial infection of birds caused by Chlamydophila psittaci. It can be transmitted to humans and can cause severe pneumonia that can be fatal if untreated....
What is Scalded Baby Syndrome?
Scalded baby syndrome is an acute bacterial infection of the skin that occurs in newborn babies and young children. It causes the skin to peel away, but is rarely fatal....
What is Toxic Shock Syndrome?
Toxic shock syndrome is a serious and potentially lethal condition that is caused by toxins released throughout the body by Staphylococcus aureus or Streptococcus pyogenes....
When Were Antibiotics Discovered?
The earliest antibiotic to be made available for treating people was penicillin. This was discovered by Alexander Fleming in 1928 but was not purified and manufactured until 1940....
Where Do Bacteria Live?
Bacteria live virtually everywhere on Earth – on land, in water, on and in plants, animals and people, in the Arctic, in the deep sea and in warm water near volcanoes....
Which Bacteria Cause Pneumonia?
Pneumonia is a life-threatening inflammation of the lungs that can be caused by infection with a wide range of different bacteria, including Streptococcus pneumoniae, the most common cause....
Which Bacterium Causes Diphtheria?
Corynebacterium diphtheriae, a gram positive aerobic bacterium is the causative agent of the disease diphtheria. This is a serious childhood infection that is usually controlled by vaccination....
Which Bacterium Causes the Plague?
Plague, also known as the Black Death, is caused by the bacterium Yersinia pestis. This spreads from infected fleas to humans, causing fatal disease....
Which Bacterium Causes Typhus?
Typhus is a bacterial infection caused by the Rickettsia species primarily. It leads to delirium and stupor and a high temperature and can be fatal if not treated promptly with antibiotics....
Whooping Cough; a Childhood Infection of the Past?
Whooping cough, caused by Bordetella pertussis, is preventable by vaccination. Immunisation in the UK has vastly reduced its incidence, but the disease remains a major killer in the developing world....
Why Can't Antibiotics Cure the Common Cold?
Antibiotics are drugs that target bacteria: they have no effect on infections caused by viruses. This is a key point and explains why taking antibiotics for viral infections such as flu and colds does...
Why is Anthrax So Feared?
Anthrax is a killer bacterial disease that can be fatal in 100 per cent of cases. Its spores can remain infectious for hundreds of years....
Why is Whooping Cough Becoming More Common?
Cases of whooping cough can and do become more common when parents in the UK fail to get their babies and children immunised against whooping cough - leading to the risk of infection and complications...