10 important (and serious) bacterial infections

10 important (and serious) bacterial infections

In this article we will describe 10 important (and serious) bacterial infections – in alphabetical order.

1. Anthrax

Causative agent: Bacillus anthracis.

Anthrax is a severe infection caused by the rod-shaped, Gram-positive bacterium called Bacillus anthracis. Anthrax comes in three forms: lung anthrax or pneumonia, skin anthrax, and intestinal anthrax. All of these forms when not treated immediately can be fatal.

This bacterium is often used in bioterrorism. Terrorists release the spores of the bacteria in crowded and public spaces or sometimes send letters which contain the spores.

2. Botulism

Causative agent: Clostridium botulinum.

Botulism is a rare yet extremely fatal bacterial disease caused by the bacterium Clostridium botulinum. This bacterium produces the substance botulinum, a type of lethal neurotoxin that paralyzes different muscles.

Botulism occurs in many types: food borne, wound, infant, and respiratory. Food borne botulism is the most common and also the most deadly.

Interestingly, the causative agent of this infection is also the same bacterium that is used to produce the ‘anti-ageing’ product’ Botox.

3. Clostridium difficile (‘C diff’)

Causative organism: Clostridium difficile

C diff is present naturally in the gut. Some antibiotics cause the bacteria to multiply and produce toxins causing diarrhoea. This usually occurs in a hospital or care home. It is an example of a ‘superbug’.

4. Cholera

Causative agent: Vibrio cholerae.

Cholera is a type of bacterial disease that is often characterised by watery diarrhoea and severe dehydration. When left untreated, it can lead to death.

This infection is caused by consuming water or food that is contaminated with the bacterium. The bacterium Vibrio cholerae, which is commonly found in environments with poor sanitation, produces a toxin that poisons the intestines.

5. Leptospirosis

Causative agent: Leptospira sp. (20+ types)

Leptospirosis (or Weils’ Disease) is a bacterial infection that can result from when eyes, nose, or an open wound is exposed to soil or water that is contaminated with the bacteria. This bacteria is commonly found in animal urine (especially rats).

When left untreated, this infection can damage the kidney, liver, lungs, and the brain.

6. Meningitis

Causative agent: Neisseria meningitidis (other bacterial include Listeria monocytogenes and Streptococcus pneumoniae).

Bacterial meningitis affects the brain and the spinal cord. During the infection, the bacterium causes swelling of the meninges (protective membranes) around the brain and spinal cord.

The bacterium is generally transmitted from one person to another via coughing and sneezing. It can also be transmitted by an infected mother to her child during labour or birth.

Typical symptoms include headache, neck stiffness, nausea, vomiting, confusion, and sensitivity to light.

7. MRSA infection

Causative agent: Methicillin-resistant Staphylococcus aureus.

The bacterium Staphylococcus aureus is a naturally occurring bacterium present in our noses. However, a different strain of that bacterium, known as the MRSA or Methicillin-resistant Staphylococcus aureus (biofilm), has evolved to become insensitive to the antibiotic methicillin. Because the bacterium is very resistant to even the most powerful antibiotics, it is another ‘superbug’.

The infection caused by this bacterium can be fatal and hard to treat. The bacterium can infect the lungs, urinary tract, and bloodstream.

8. Pneumonia

Causative agent: Streptococcus pneumoniae (other bacteria include Staphylococcus aureus, Group A Streptococcus, Klebsiella pneumoniae, Haemophilus influenzae,  Legionella pneumophila and Mycoplasma pneumoniae).

Pneumonia is an infection in the lungs and can be caused by bacteria, viruses, or fungi. The alveoli (air sacs) of the lungs become filled with pus, making it hard to breathe.

Symptoms of this infection include cough with yellow/green sputum, shortness of breath, chest pain, fever, and night chills.

9. Tetanus

Causative agent: Clostridium tetani.

Also known as ‘lockjaw’, tetanus is an often fatal bacterial infection that affects the brain and the nervous system. It is caused by the bacterium Clostridium tetani that produces a toxin that paralyzes muscles.

Common sources of the bacteria include contaminated saliva or faecal matter, unsanitary surgical procedures, animal and insect bites.

10. Tuberculosis

Causative agent: Mycobacterium tuberculosis.

Tuberculosis is a highly contagious long-term infection, especially in the lungs. It symptoms include fever, weight loss, night sweats and persistent cough that may last for many months.

The causative agent of tuberculosis (or commonly called TB) is an airborne pathogenic bacteria that can be transmitted from one person to another via sneezing and coughing.

Other infections (also in alphabetical order)

Bubonic Plague

Causative agent: Yersinia pestis.

Caused by the bacterium Yersinia pestis, bubonic is the most common type of plague. This bacterial disease is characterised by the swelling of lymph nodes (called buboes) in the groin and armpits. The bacterium is usually transmitted by infected fleas, that can be  carried by rats.

The second bubonic plague, known as the Black Death, ravaged Europe, North Africa, and Asia from 1346 to 1353; and is estimated to have caused up to 200 million deaths – as many as 60 % of the population of Europe at the time.

E.Coli urinary tract infection (UTI)

Causative agent: Escherichia coli.

The commonest cause of UTI is the faecal coliform bacterium E.coli.

Gonorrhoea

Causative agent: Neisseria gonorrhoeae.

Also called as ‘the clap’, gonorrhoea is the second most prevalent sexually transmitted disease (HIV/AIDS is first). It is caused by the bacterium Neisseria gonorrhoeae that is transmitted during sexual contact.

Gonorrhoea, when left untreated can cause severe complications: on women, these include infection of the fallopian tubes and uterus; in men, the bacterium may cause the infection of the epididymis.

Pseudomonas 

Causative agent: Pseudomonas aeruginosa.

Caused by Pseudomonas aeruginosa, pseudomonas infection targets the respiratory system. Here, the bacterium damages the lungs and worsens the conditions of people with cystic fibrosis.

The bacterium is ubiquitous and therefore can infect people in many ways. It can be obtained by using contaminated surgical equipment, may spread through food, or transmitted via physical contact.

Syphilis

Causative agent: Treponema pallidum.

Syphilis is another bacterial disease transmitted via sexual activity. It can also be transmitted via physical contact and prolonged kissing. Moreover, infected pregnant mothers can pass the bacterium to their babies during labour and birth.

Syphilis spread from sores and can cause damage organs like the eyes, brain, and joints.

Summary

We have described 10 important (and serious) bacterial infections. We hope you have found it helpful.

 

Last Reviewed on 9 March 2024