MMI

Overview of course content covering bacteria, viruses, immunology, and their connections to public health.
Emphasis on prevention strategies including vaccines and antibiotics.
Relation of immunology to controlling disease spread.

The skin acts as a primary defense against infections due to its:
- Dryness, which is inhospitable for bacteria.
- High salt content and inhibitory substances (like sebum) present on the skin.
- Presence of lysozyme in skin that breaks down bacterial cell walls.
Most bacteria on skin are gram-positive, particularly those with thicker peptidoglycan layers that confer strength and resistance to adverse conditions.
Normal skin flora persists despite washing, indicating limited effectiveness of washing in eliminating bacteria.
Areas of skin with moisture (e.g., armpits, under breasts) foster larger bacterial populations due to favorable growth conditions.

Composition of bacteria on the skin:
- Both aerobic and anaerobic species, with anaerobic being the more prevalent type.
- Notable genera include Staphylococcus, Micrococcus, and Diphtheroids.
- Major mention of Staphylococcus epidermidis as a dominant species in skin flora.

Mucous membranes cover internal cavities and consist of:
- Layers of epithelial cells with goblet cells that produce mucus.
- Presence of cilia that helps to expel pathogens and debris from the membranes.
The acidity of mucous membranes (e.g., in the mouth and vaginal canal) supports microbiota like Lactobacillus, which protects against infections.

Eyes: Surface seen as an extension of the skin; various bacteria exist but low risk for infections as long as they remain at low levels.
The internal eye is sterile, highlighting the importance of shunning pathogens.

Common causes and types of eye infections including:
- Trachoma: Caused by Chlamydia trachomatis, primarily in developing countries, leading to blindness through follicular infections.
- Inclusion conjunctivitis: Occurs when pathogens from the genitalia infect the eye (e.g., via hand contact).
- Prevention strategies for neonatal infections include screening pregnant women and administering antibiotic drops to newborns.

Types of rashes:
- Vesicular rash: Blister-like, less than 1 cm in diameter; larger than 1 cm is termed a bullae rash.
- Maculopapular rash: Indication of immune cell activity in skin infections (e.g., measles).
Description of Staphylococcus aureus and its roles in infections, including characteristic features:
- Produces coagulase, which converts fibrinogen to fibrin, leading to clot formation.
- Variety of virulence factors (e.g., toxins, proteases) that enable bacteria to evade immune response.

Toxic shock syndrome: Life-threatening condition caused by superantigens from Staphylococcus aureus; symptoms include fever, rash, and shock.
Scalded skin syndrome: Caused by toxins from staphylococcus leading to skin sloughing, treatable with antibiotics.

Streptococcus species divided into groups based on hemolytic properties; key focus on Group A (S. pyogenes) and Group B (S. agalactiae).
Beta-hemolytic streptococci as significant pathogen sources for skin infections; noted for M protein as a virulence factor.
Complications of S. pyogenes infections include necrotizing fasciitis (flesh-eating disease) and rheumatic fever.

Proper identification of bacterial strains important for treatment selection, particularly in urinary tract infections caused by Staphylococcus saprophyticus in women.
Treatment protocols vary by severity of diagnosis; superficial infections may resolve without antibiotics.

Introduction to viral skin infections with special emphasis on wart types and their effects on immunocompromised individuals.
Discussion of herpes viruses as common pathogens; specific focus on herpes simplex virus types 1 and 2.

High infectiousness of the measles virus (90% attack rate) and its implications for public health; vaccination strategies discussed.
Measles complications include immunosuppression, with long-term impacts on cellular immunity.

Review of major microbial pathogens relevant to skin and eye infections.
Importance of understanding bacteria, viruses, vaccination, and immune responses in preventing disease spread and managing public health issues.