Bacterial Pathogens: Staphylococcus & Neisseria

Staphylococcus aureus

• Spherical, gram-positive bacteria arranged in clusters.
• Transmitted through direct contact with infected individuals, contaminated objects, or inhalation of respiratory droplets.
• Enters the body via skin wounds, hair follicles, or glands.
• Associated diseases include MRSA, local cutaneous infections (folliculitis, furuncle, carbuncle, impetigo), bacteremia, osteomyelitis, food intoxication, and toxic shock syndrome.
• Symptoms: skin infections (red, painful areas, pus-filled blisters), food poisoning (nausea, vomiting, diarrhea), toxic shock syndrome (high fever, rash, confusion).
• Untreated infections can lead to severe conditions such as bloodstream infections and pneumonia.
• Diagnosis through culture from infected areas or exposure history.

Neisseria meningitidis

• Non-spore forming, non-motile, encapsulated gram-negative diplococcus with a kidney bean shape.
• Transmission is via mucosal attachment, entering the bloodstream, and crossing the blood-brain barrier, potentially leading to meningitis.
• Human nasopharynx serves as its natural reservoir.
• Rapidly onset disease characterized as meningitis with symptoms including fever, sore throat, headache, and stiff neck.
• Untreated cases can result in cognitive impairment, learning disabilities, and death.
• Diagnosis involves gram stain, CSF, and blood tests.
• Treatment includes cephalosporins that penetrate the blood-brain barrier.
• Preventable by vaccination.

Clostridium perfringens

• Pleomorphic, gram-positive bacteria with straight or curved rods, non-motile and capsulated.
• Symptoms may mimic neuromuscular conditions, with initial fever, headache, and dizziness.
• If untreated, can lead to severe cardiac and neurological complications.
• Diagnosis involves Lyme antibody tests.
• Treatment options include tetracycline or amoxicillin.
• Prevention strategies include protective clothing, insect repellent, and pest control.

Vibrio cholerae

• Curved, gram-negative, aerobic rod-shaped bacteria.
• Ingestion through contaminated food or water is the primary mode of transmission.
• Infects the mucous barrier of the small intestine and is non-invasive.
• Causes cholera, characterized by severe diarrhea and electrolyte loss due to cholera toxin.
• Symptoms include "rice-water" stool, muscle cramps, severe thirst, and hypotension.
• Untreated, patients can lose up to 50% of body weight.
• Diagnosis through stool cultures or rapid dipsticks.
• Treatment includes rehydration and tetracycline administration.
• Preventative measures involve proper sewage disposal and water purification.

Additional Pathogens

• Streptococcus pneumoniae: Spherical, alpha-hemolytic bacteria found in pairs, non-motile.
• Listeria monocytogenes: Rod-shaped, non-spore-forming, catalase-positive, facultative anaerobic organisms.
• Mycobacterium tuberculosis: Acid-fast bacteria, rod-shaped, strictly aerobic, causes tuberculosis.
• Bordetella pertussis: Coccoid, gram-negative, encapsulated, non-spore-forming bacteria that causes whooping cough.
• Treponema pallidum: Spirochete, helically coiled, responsible for syphilis.
• Borrelia burgdorferi: Spiral-shaped spirochete causing Lyme disease, equipped with flagella.
• Helicobacter pylori: Aerophilic, helical-shaped with flagella, linked to stomach ulcers.

Viruses

• Herpes simplex 2: DNA virus, double-stranded, encapsulated.
• Epstein-Barr: DNA virus, double-stranded, encapsulated, associated with mono.
• Hepatitis B: DNA virus, both single and double-stranded, encapsulated, affecting liver.
• Morbillivirus (measles): RNA virus, single-stranded, encapsulated, causes measles.
• HIV: RNA virus, single-stranded, encapsulated, leads to AIDS.

Explore the characteristics and diseases associated with Staphylococcus aureus and Neisseria meningitidis. This quiz covers transmission, symptoms, and diagnosis of these significant bacterial pathogens. Test your knowledge on the various infections caused by these bacteria.