BIOS 242 Week 6 Disease Worksheet

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Chamberlain University

BIOS-242 Fundamentals of Microbiology

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Date

Disease Worksheet

Staphylococcal Scalded Skin Syndrome (SSSS)

Staphylococcal Scalded Skin Syndrome (SSSS) is caused by Staphylococcus aureus, a Gram-positive bacterium known for its resilience, as it can survive on surfaces from hours to weeks. This bacterial pathogen primarily affects the skin. Its virulence factors include antigens, capsules, adhesins, and several enzymes such as coagulase, lipase, hyaluronidase, and staphylokinase.

Signs and Symptoms: Children with SSSS often present with fussiness, fatigue, fever, skin redness, and fluid-filled blisters. In severe cases, large sheets of skin may peel away.

Pathogenesis and Epidemiology: The disease results from an exfoliative toxin produced by approximately 5% of S. aureus strains. It typically originates in the oral or nasal cavity or around the umbilicus. SSSS affects nearly 56 cases per 100,000 individuals, mostly in neonates and young children.

Treatment and Prevention: Management includes intravenous antibiotics, with prevention strategies focusing on avoiding primary staphylococcal infections and maintaining hygiene during childbirth.

Necrotizing Fasciitis

Necrotizing Fasciitis, often referred to as “flesh-eating disease,” is caused by Streptococcus pyogenes or Staphylococcus aureus. Both are Gram-positive bacteria that can survive in aerobic and anaerobic environments. This bacterial infection targets tissues beneath the skin and spreads rapidly.

Signs and Symptoms: Patients commonly experience severe pain disproportionate to physical findings, fever, fatigue, muscle aches, and rashes resembling sunburn.

Pathogenesis and Epidemiology: The condition progresses quickly, causing massive tissue necrosis. Its incidence is estimated at 0.40 per 100,000 adults and 0.08 in children.

Treatment and Prevention: Effective treatment requires immediate intravenous antibiotics and surgical removal of necrotic tissue. Preventive measures include proper wound care and prompt cleaning of cuts with soap and water.

Chickenpox and Shingles

Chickenpox and shingles are caused by the Varicella-zoster virus. The incubation period for chickenpox ranges from 14 to 16 days, while shingles emerges years later as the virus reactivates in the nervous system.

Signs and Symptoms: Chickenpox is characterized by fatigue, fever, and a widespread itchy rash. Shingles manifests as a painful localized rash, often accompanied by long-term nerve pain.

Pathogenesis and Epidemiology: Transmission occurs through inhalation of respiratory droplets or contact with skin lesions. In the U.S., over 95% of individuals contract chickenpox by the age of 20.

Treatment and Prevention: Vaccination is the most effective preventive strategy. Antiviral drugs such as acyclovir help reduce the severity and duration of infection.

Trachoma

Trachoma is a chronic eye infection caused by Chlamydia trachomatis, a Gram-negative obligate intracellular bacterium. It exhibits distinct life cycles, alternating between elementary and reticulate bodies.

Signs and Symptoms: The disease presents as persistent eye inflammation, irritation, and eventual scarring, leading to blindness if untreated.

Pathogenesis and Epidemiology: Globally, approximately 229 million people are affected. Recurrent infections exacerbate corneal scarring, making it the leading infectious cause of blindness.

Treatment and Prevention: Management includes antibiotics such as azithromycin. Preventive efforts focus on sanitation, facial cleanliness, and improved access to clean water.

Bacterial Meningitis

Bacterial meningitis is caused by multiple pathogens, including Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, Listeria monocytogenes, and Streptococcus agalactiae. These Gram-negative diplococci thrive at 35–37°C with increased carbon dioxide.

Signs and Symptoms: Patients present with high fever, headaches, stiff neck, confusion, photosensitivity, and, in some cases, a purpuric skin rash.

Pathogenesis and Epidemiology: The infection often develops after bacteremia, spreading hematogenously to the meninges. It is a medical emergency due to its high mortality rate.

Treatment and Prevention: Treatment involves intravenous antibiotics and corticosteroids. Preventive strategies include hand hygiene and avoiding sharing utensils. Vaccinations against Neisseria meningitidis and Haemophilus influenzae have greatly reduced incidence.

Variant Creutzfeldt-Jakob Disease (vCJD)

Variant Creutzfeldt-Jakob Disease (vCJD) is caused by abnormal prion proteins, which misfold normal cellular proteins, leading to progressive neurological deterioration.

Signs and Symptoms: Patients experience personality changes, memory impairment, blurred vision, speech difficulties, insomnia, and motor dysfunction.

Pathogenesis and Epidemiology: The disease spreads through the conversion of normal prion proteins into pathogenic forms. Although rare, vCJD remains fatal, with no known cure.

Treatment and Prevention: There are no effective treatments. Preventive measures include strict regulation of beef products and medical sterilization practices.

Septicemia

Septicemia, commonly known as blood poisoning, is caused by bacteria such as Staphylococcus aureus and Streptococcus pneumoniae. These Gram-positive facultative anaerobes affect the cardiovascular system and major organs.

Signs and Symptoms: Patients present with fever, chills, nausea, fatigue, and discolored skin due to impaired blood circulation.

Pathogenesis and Epidemiology: The infection triggers a systemic inflammatory response, leading to sepsis. In the U.S., approximately 1.7 million adults are affected annually.

Treatment and Prevention: Antibiotics and supportive care, including fluid resuscitation, are standard. Preventive measures include reducing risk factors such as smoking and avoiding drug misuse.

Endocarditis

Endocarditis is primarily caused by Viridans streptococci and Pseudomonas aeruginosa. These bacteria colonize damaged cardiac tissue, leading to heart valve infections.

Signs and Symptoms: Patients may experience flu-like symptoms, chest pain, joint aches, and swelling in the legs or abdomen.

Pathogenesis and Epidemiology: The condition occurs in 2.6 to 7 cases per 100,000 annually, particularly in individuals with preexisting heart conditions.

Treatment and Prevention: Intravenous antibiotics are the primary treatment. Preventive strategies emphasize dental care and proper hygiene to reduce bacterial entry into the bloodstream.

Lyme Disease

Lyme disease is caused by Borrelia burgdorferi, a spiral-shaped bacterium with an atypical Gram-negative membrane. Unlike most pathogens, it uses manganese instead of iron to evade immune detection.

Signs and Symptoms: The hallmark symptom is erythema migrans, a circular rash around the tick bite. Additional symptoms include fever, fatigue, and neurological issues.

Pathogenesis and Epidemiology: Transmitted through tick bites, the bacterium spreads via the bloodstream, affecting joints, skin, heart, and the nervous system. It remains the most common vector-borne illness in North America and Europe.

Treatment and Prevention: Antibiotic therapy is effective, particularly when initiated early. Preventive efforts include using insect repellent, wearing protective clothing, and reducing tick habitats.

Infectious Mononucleosis

Infectious Mononucleosis, commonly called the “kissing disease,” is caused by the Epstein-Barr virus (EBV). The virus establishes latency in B lymphocytes, evading immune detection.

Signs and Symptoms: Patients often present with extreme fatigue, fever, sore throat, swollen lymph nodes, and occasional rash.

Pathogenesis and Epidemiology: Transmission occurs through contact with saliva and respiratory secretions. In the U.S., about 500 cases occur per 100,000 annually.

Treatment and Prevention: Supportive care, including rest, hydration, and balanced nutrition, is essential. Preventive strategies include avoiding close contact and not sharing utensils with infected individuals.

Summary Table of Diseases

References

Centers for Disease Control and Prevention. (2021). Bacterial meningitis. https://www.cdc.gov/meningitis

Ghosh, S., & Rajesh, G. (2020). Understanding infectious mononucleosis. Journal of Infectious Diseases, 221(2), 298–310.

Johnson, J. (2022). Trachoma and eye health. Global Health Journal, 15(4), 112–118.

BIOS 242 Week 6 Disease Worksheet

National Institutes of Health. (2020). Lyme disease: Diagnosis and treatment. https://www.nih.gov

World Health Organization. (2021). Global health estimates: Leading causes of death. https://www.who.in