micro 9-12

folliculitis

• Infection of hair follicle 

• Pimple 

• Stye @ eyelid base 

• Staphylococcus aureus

impetigo

• Sores 

• Contagious 

• S.aureus 

• Streptococcus pyogenes 

necrotising fascitis (flesh eating disease)

streptococcous pyogenes

acne

Cutibacterium acnes  

Complication of burns

Pseudomonas aeruginosa  

Cutaneous anthrax  

• Eschar: black, painless ulcer 

• Class 2 biohazard 

• Bacillus anthracis  

gas gangrene

• Death of muscle and connective tissue 

• Blackening of infected muscle and skin 

• Gas bubbles 

• Clostridium perfringens

Macular

redness, flat

Papular

small raised bumps, redness, by T cells

Maculopapular

combination of flat, discolored spots (macules) and small, raised bumps (papules) on a reddish background 

Vesicular

small, fluid-filled blisters called vesicles

Pustular

vesicular rash becomes secondarily infected with bacteria, pus and raised 

herpes

• Painful lesions caused by inflammation and cell death  

• Spread between mucous membranes of mouth and genitals

• Lab diagnosis: molecular biology   

• Caused by human herpesviruses 1 and 2 (HSV1 and HSV2) 

• HSV1: cold sores, close contact, 

• HSV2: genital herpes, sexual intercouse 

warts 

• Benign epithelial growths on skin or mucous membranes 

• Papillomaviruses  

chicken pox and shingles

Varicella-zoster virus (VZV) 

rubella

• Mild rash 

• Congenital infection can result in birth defects or death of fetus  

• Infection spreads from the respiratory tract throughout the body  

• Rubella virus 

cytaneous mycoses

• Cutaneous lesions  

• Dermatophytes  

• Ring worm 

bacterial entry to CSF

1. Most common: haematogenous – inflammation can alter permeability of blood-brain barrier 

2. Less common: breaks in bones and meninges, medical procedures, travel in peripheral neurons to CNS 

bacterial meningitis

• Sudden high fever, severe meningeal inflammation and increased WBCs in CSF 

• HSV 

• Neisseria meningitidis 

• Streptococcus pneumoniae 

• Haemophilus influenzae 

• Listeria monocytogenes 

• Streptococcus agalactiae (GBS of neonates) 

• Opportunistic members of normal microbiota  

Arboviral encephalitis 

Transmitted by mosquitos  

Cryptococcal meningitis 

• Loss of vision and coma in later stages 

• Cryptococcus neoformans  

Prion disease 

• Mad cow disease 

• Medical procedures can spread the disease (heat resistant) 

• Spreads bad folds of proteins, normal prions into abnormal form 

Trachoma

• Scarring of conjunctiva and cornea 

• Chlamydia trachomatis (not STI) 

Dental caries, gingivitis and periodontal disease

• Holes or pits in teeth

• Streptococcus mutans

Peptic ulcers

• abdominal pain

• Flagella burrows through stomach lining

• Adhesins attach to gastric cells

• Urease test, neutralises stomach acid

• Helicobacter pylori

Bacterial gastroenteritis - Bali belly

• shigellosis

• Diarrhoea, dysentery

• Small intestine

• Shigella

Bacterial gastroenteritis: Traveler’s diarrhoea

• E.coli (ETEC)

• Entero, toxin, e.coli

Bacterial gastroenteritis - campylobacter diarrhoea

• campylobacter jejuni

• 3x effects of salmonella

• Curved/coiled

Bacterial gastrointestinal - anti-microbial associated diarrhoea

• clostridiodes difficile

• Antimicrobial use of facilitates overgrowth

• Toxins

Bacterial gastroenteritis - salmonellosis and typhoid fever

• typhoid fever: typhoid and paratyphi serotypes

  • Contaminated food or water

• Salmonellosis: enteritidis and typhimurium

  • Contaminated eggs

Bacterial food poisoning

• nausea, vomiting, diarrhoea, cramping

• Staphylococcus aureus

Viral gastroenteritis

• norovirus, rotavirus

• Most common cause to gastroenteritis

Viral hepatitis

• Hepatitis A (HAV): anal – faecal-oral

• Hepatitis B (HBV): blood – envelope virus

  • Surface and core antigen

• Hepatitis C (HCV): bloodborne

Giardiasis

• asymptomatic

• Giardiasis intestinalis

• Cysts are resistant to chlorine, heat, drying and stomach acid

Cryptosporidiosis

• watery diarrhoea

• Resistant to chlorine

• Cryptosporidium paryum

Amebiasis

• trophs motile

• Produce proteins that are toxic to cells

• Entamoeba histolytica

Bacterial vaginosis

• loss of lactobacilli

• Overgrowth of other bacteria

Vaginak candidiasis

• Endogenous infection as normal microbiota of skin and mucous membranes

• Candida albicans

Gonorrhea

• women asymptomatic

• Neiserria gonorrhoea

Chlamydia

• molecular tests

• Chlamydia trachomatis

Syphilis

treponema pallium

• primary - painless lesion

• Secondly - rash

• Tertiary - hole in head

Trichomoniasis

• Vaginal discharge and irritation

• Males asymptomatic

• Trichomonas vaginalis

Septicaemia

• microbial infection of the blood that produces systemic toxicity (high grade fever and shock)

Bacteraemia

• presence of bacteria in the blood without toxicity but may result in low grade fever

• Staph aureus

Lymphangitis

Infection and inflammation of lymphatic vessels

middle ear infection source

• Streptococcus pneumoniae

UTI, urine, source blood

E.coli

Wound source blood

Staphylococcus aureus

Skin, heart valve source blood

Staphylococcus epidermis

CSF blood source

Meningococcus

Mouth source blood

Non-pneumococcal streptococcus

Brucellosis

• biohazard cupboard

• Brucella spp.

Bubonic Plague

• BSL3

• yersinia pestis

Lyme disease

• borrelia burgodorferi

Infectious mononucleosis

• severe sore throat and fever

• Epstein-barr virus

Cytomegalovirus (CMV) diseases

• asymptomatic most cases

• Cytomegalovirus

Dengue fever

• internal bleeding, showcases, possible death

• Aedes mosquitoes

African viral haemorrhagic fever

• fever and fatigue

• Ebola virus or marburgvirus

Malaria

• mosquito vector

• Fever, chills, diarrhoea

• P.falciparum

Toxoplasmosis

• fever, malaise, inflammation

• Toxoplasma gondii

Schistomiasis

• Swimmer’s itch

• Burrows into bladder wall

• Eggs deposited throughout body

• Schistosoma

Diphtheria

• sore throat, localised pain, fever

• Corynebacterium diphtheriae

Rhinosinutus and otitis

• Congestion, headache, pain in ear

• Streptococcus pneumoniae, aureus, haemophilia influenzae

Common cold

Enteroviruses (rhinovirus)

Bronchitis

Streptococcus pneumoniae, haemophius influenzae, staphylococcus aureus

Community aquired pneumonia

• strep pneumoniae

• Haemophilus influenzae

• Staph aureus

Bacterial pneumonias

• mycoplasma pneumoniae

• Streptococcus pneumoniae

Primary atypical pneumoniae

• Fever, malaise, sore throat, excessive sweating

• mycoplasma pneumoniae

Legionnaires disease

Legionella pneumophila

Tuberculosis

• Mycobacterium tuberculosis

• Very hard cell wall

Whooping cough

Bordetella pertusis