Microbiota and Skin Infections

Microbiota of Skin

• Common skin bacteria include Streptococcus, Staphylococcus, Corynebacterium, and Propionibacterium.
• Yeasts like Candida are also present.
• Pseudomonas and Lactobacillus are also found on the skin.

Impetigo

• Caused by Staphylococcus aureus or Streptococcus pyogenes (often a mix).

Chickenpox & Shingles

• Caused by Varicella-Zoster Virus (HHV-3).
• Exposure to shingles fluid can cause chickenpox in someone who hasn't had chickenpox.
• Chickenpox is a disease caused by the varicella-zoster virus.
• Shingles develops by the reactivation, or reactivation of the varicella zoster virus.

Scarlet Fever

• Caused by Streptococcus pyogenes (strep throat).
• Erythrogenic exotoxin produced by S. pyogenes causes scarlet fever.
• Rheumatic fever is a possible consequence if not treated.
• Scarlet fever rash feels like sandpaper.

Roseola

• Caused by HHV-6.
• High fever lasting up to 3 days.
• Maculopapular rash (30% of cases) appears, usually on the fourth day of fever.
• Nearly all US adults have been infected by HHV 6.
• There's no specific treatment or prevention.

Measles

• Caused by measles virus.
• Maculopapular rash characterized by pink macules and papules.
• Often treated with supportive care.

Rubella

• Caused by rubella virus.
• Rash characterized by pink macules and papules.
• Can have teratogenic effects (miscarriage or birth defects) if contracted during the first trimester.
• Prevention/treatment through MMR vaccine.

Smallpox

• Caused by Variola virus.
• Variola major is a more severe form causing shock and toxemia.
• Variola minor is less severe and less fatal.

Fifths Disease

• Caused by Parvovirus B19.
• Rash begins on the face and worsens with increased body temperature/activity.

Capitis

• Fungal infection of the scalp, hair, eyebrows, or eyelashes.

Barba

• Fungal infection of the beard in men.

Corporis

• Fungal skin infection that's widespread (more generalized skin infections).

Cruris

• Fungal infection in the groin, genitals, or buttock area.

Pedis

• Fungal infection in the feet.

Unguium

• Fungal infection of the fingernails or toenails.

Molluscum Contagiosum

• Caused by poxvirus.
• Characterized by smooth, waxy nodules on the skin.
• Transmitted through direct contact or sexual contact.
• No definitive treatment.

Normal Biota of CNS

• No significant bacteria or fungi are generally found in the cerebrospinal fluid (CSF) in normal conditions.

Aseptic Meningitis

• Viral infection causing meningitis.
• Common in children, primarily caused by enteroviruses.
• Resolves within 2 weeks; no specific bacterial or fungal cultures.

Poliomyelitis

• Caused by poliovirus.
• Usually presents as flaccid paralysis, especially in respiratory muscles.

Toxoplasmosis

• Caused by the parasitic protozoan Toxoplasma gondii.
• Pregnant women can transmit the infection to the fetus.
• Definitive hosts are adult cats.

Rabies

• Fatal encephalitis caused by a virus found in wild animals.
• Can be transmitted through bite, scratch, or inhalation.

Meningoencephalitis

• Caused by the amoeba Naegleria fowleri.
• Often leads to death due to the amoeba's invasion and destruction of the brain and spinal tissues.

Paralysis

• Includes cases of flaccid (weak muscles) paralysis caused by polio or botulism, and rigid (stiff muscles) paralysis caused by tetanus.

Lyme Disease

• Caused by the spirochete Borrelia burgdorferi.
• Characterized by erythema migrans, which is seen as a bull's-eye rash caused by ticks.
• Symptoms include stiff neck, cardiac issues and neurological symptoms without treatment.

Infectious Mononucleosis (Mono)

• Caused by Epstein-Barr virus (EBV).
• Characterized by fatigue and marked cervical lymphadenopathy (swollen lymph nodes in the neck).

Hemorrhagic Diseases

• Includes yellow fever, dengue fever, Ebola, and Marburg fever, often characterized by bleeding-related issues.

Cat Scratch Disease

• Caused by Bartonella henselae.
• Characterized by localized lymphadenopathy following a cat scratch or bite.

Pertussis (Whooping Cough)

• Caused by Bordetella pertussis.
• Characterized by violent coughing attacks.

Atypical Pneumonia

• Primarily caused by Mycoplasma pneumoniae.
• Frequently involves bronchitis in patients.

Influenza

• Caused by influenza viruses (types A, B, and C).
• Characterized by fever, cough, sore throat, and other symptoms.

E. coli O157:H7

• Strain of E. coli that can cause severe illness, including hemolytic uremic syndrome (HUS).
• Often associated with undercooked or contaminated meat.

Shigellosis

• Caused by Shigella species.
• Characterized by dysentery (bloody diarrhea), as well as nausea and vomiting.
• Associated with improper hygiene and sanitation.

Taenia solium

• Tapeworm parasite that can infect pigs, and humans.
• Usually asymptomatic, but more severe cases can occur and cause vague abdominal pain, nausea and worms in feces.

Trichinosis

• Parasitic roundworm infection transmitted through eating undercooked pork
• Characterized by muscle and neurological problems

Infectious Conditions, Genital Lesions

• Syphilis
• Genital herpes

Viral Sexually Transmitted Infections (Wart-Like)

• Human Papillomavirus (HPV)
• Molluscum contagiosum