Back to: MICROBIOLOGY 300 LEVEL
Welcome to class!
It’s so good to see you again, and I’m excited for today’s lesson. You’re learning the names of microorganisms that are more than just tongue-twisters—they’re real-life disease-causing agents affecting people across Nigeria and beyond. Today, we’re focusing on Streptococcus pneumoniae, Mycobacterium tuberculosis, and Bordetella pertussis—three bacteria that mainly affect the respiratory system. If you’ve ever heard someone coughing persistently in your neighbourhood or seen a health campaign for tuberculosis, then this topic is already part of your reality.
Streptococcus Pneumoniae, Mycobacterium Tuberculosis, Bordetella Pertussis
Streptococcus pneumoniae
This bacterium is a Gram-positive, lancet-shaped diplococcus—meaning it usually appears in pairs under the microscope.
Where it lives:
It commonly resides in the nose and throat of healthy people without causing illness. But when the immune system is weak, it can cause disease.
Diseases caused:
Pneumonia (especially in children and the elderly)
Otitis media (ear infection)
Meningitis
Sinusitis
Bacteraemia (blood infection)
Mode of transmission:
Spread through droplets when someone coughs or sneezes.
Risk groups:
Children under 5, elderly people, people with HIV/AIDS, or those without access to good healthcare.
Prevention:
Vaccines like the pneumococcal conjugate vaccine (PCV), proper hygiene, and treating underlying conditions.
Imagine a child in Kano with a high fever, cough, and chest pain. After a hospital visit, the doctor confirms pneumonia caused by Streptococcus pneumoniae—very common and very preventable with early care.
Mycobacterium tuberculosis
This is a slow-growing, acid-fast bacillus and the causative agent of tuberculosis (TB).
Where it affects:
Mainly the lungs, but can also affect bones, brain, kidneys, and more.
How it spreads:
Airborne droplets from a person with active TB. One sneeze can spread thousands of bacteria into the air.
Symptoms of pulmonary TB:
Persistent cough (more than 2 weeks), weight loss, night sweats, fever, and coughing up blood.
Diagnosis:
Sputum microscopy, GeneXpert test, chest X-ray, and tuberculin skin test.
Treatment:
A strict 6-month regimen of antibiotics like isoniazid, rifampicin, ethambutol, and pyrazinamide.
Public health importance:
TB is a major health issue in Nigeria, especially where housing is crowded or healthcare access is limited.
Bordetella pertussis
This bacterium causes whooping cough (pertussis), a serious respiratory illness especially dangerous for babies.
Structure:
It’s a Gram-negative coccobacillus.
Symptoms:
Starts like a cold (sneezing, mild fever), then progresses to severe coughing fits followed by a high-pitched “whoop” sound when the person breathes in. Infants may stop breathing altogether.
Transmission:
Through droplets from coughing or sneezing.
Complications:
Pneumonia, seizures, brain damage, and death—especially in babies under 1 year.
Prevention:
DTP vaccine (Diphtheria, Tetanus, Pertussis) given as part of the National Immunisation Programme.
Example in life:
A baby in a rural clinic in Benue suddenly starts gasping for air after weeks of coughing. The healthcare worker quickly suspects pertussis and refers for urgent care.
Summary
- Streptococcus pneumoniae causes respiratory infections like pneumonia and meningitis.
- Mycobacterium tuberculosis causes TB, which spreads through air and requires long-term antibiotic treatment.
- Bordetella pertussis causes whooping cough and is especially deadly for infants.
- Vaccination, early diagnosis, and public health education are essential for controlling these diseases.
Evaluation
- What diseases are commonly caused by Streptococcus pneumoniae?
- How is Mycobacterium tuberculosis transmitted?
- Why is Bordetella pertussis more dangerous for babies than adults?
Each lesson builds your knowledge and your power to save lives and impact communities. Keep showing up with this same energy and focus—Afrilearn is proud to support your journey to becoming a top scientist and leader in your field. See you in the next class!