Pathogens Flashcards
What is pathogenesis?
the ability of a micro-organism to causes disease
What is a pathogen?
any organism OR agent that produces a disease
What is virulence?
intensity of disease/ degree of harm caused
What is an acute infection?
Sudden/rapid, usually short-lived. Can be severe
e.g. common cold, acute appendicitis
What is a chronic infection?
Develops slowly. Long-lasting and/or recurrent
e.g. chronic hepatitis, Tuberculosis
What is a latent infection?
Appears a long time after initial infection
e.g. Herpes, Shingles, Tuberculosis
What is an HCAI?
Results from direct treatment in a healthcare setting or contact with a healthcare setting
What is an opportunistic infection?
Caused by organisms that DON’T normally infect healthy hosts.
e.g. S. aureus, C. albicans, C. diff
What is a primary infection?
Initial infection within a patient
e.g. surgical site infection, urinary tract infection
What is a secondary infection?
Infections that follow a primary infection
e.g. infections of blood stream (septicaemia)
bones & joints
What is septecaemia?
A life-threatening condition arising from pathogenic organisms in the blood
What is bacteremia?
bacteria in the blood stream
What are Group A Streptococcus?
common in throat and skin infections
(invasive cause TSS and necrotising fascitis)
What are Group B Streptococcus?
Gut / urinary tract / Vagina
UTI, skin, bloodstream, pneumonia, soft-tissue bone and joint infections
What are the most common URT infections?
Pharyngitis, tonsilitis and strep throat
What are the 3 symptoms and 3 complications associated with URT infections?
Symptoms
- Inflamed tonsils
- difficulty swallowing
- fever
Complications
- Tonsillar abcesses
- otis media
- sinusitis
What are the 3 less common symptoms of URTs?
- Scarlet fever - strep + rash
- Autoimmune effects - rheumatic fever, glomerulonephritis
- Invasive infection - TSS
What are the 6 symptoms of acute otitis media?
Pain in ear
Hearing loss
Dizziness
Fever
Vomiting
Diarrhoea
What does chronic otitis media cause?
Tissues surrounding eustachian tube swell and get blocked.
Air in middle ear gets absorbed into tissues, and vacuum forms in ear and fluid build up and leads to glue ear
What are the 6 symptoms of conjunctivitis?
Redness in eye
Increased tears,
Thick crusty discharge after waking,
Green or white discharge during day,
Burning eyes
Blurred vision
What is trachoma?
STI associated conjunctivitis
Spread by contact (towels, touch, flies)
Leading cause of blindness in low income countries – if left untreated
Which bacteria causes chlamydia?
Chlamydia trachomatis
Which bacteria causes gonorrhoea?
Neisseria gonorrhoeae
What are the 4 symptoms of acute bronchitis?
- Non productive cough
- shortness of breath
- fever
- chest pains (lasts 10-11 days)
What are the 2 symptoms of chronic bronchitis?
- persistent cough (> 3 months),
- excessive mucus secretion
What are the 3 causes of chronic bronchitis?
Inflammation of trachea & bronchi
Usually due to smoking/irritants
Exacerbated by bacterial infection
What are the 4 symptoms of pneumonia?
Fever
Cough (productive)
Shortness of breath
Difficulty / pain on breathing
What is pneumonia?
Infection of lungs, inflammation of alveoli
What are the 4 symptoms of tuberculosis?
Persistent productive cough (> 3 weeks)
Blood in sputum
Chest pain, shortness of breath,
Fever (night), fatigue
Which bacteria causes tuberculosis?
Mycobacterium tuberculosis
What 5 things increases the risk of a lower UTI?
- Length of urethra- more common in women
- Catheterisation (50%)
- Disruption of normal urine flow- eg pregnancy, - enlarged prostate
- Older age
- Diabetes (more severe infections)
What are the 3 most common bacteria that ascending cause UTIs?
E. coli
Klebsiella
Proteus
What are the 5 main symptoms of an ascending lower UTI?
- Difficulty in passing urine/pain on urination (dysuria)
- Increased urge to urinate
- Urine may be cloudy/smelly
- Dull pain in pubic region
- Back pain/ generally unwell
(difficult to diagnose) in elderly or catheterised patients difficult to diagnose
What are the 4 main symptoms of an ascending upper UTI?
- Fewer UTI symptoms
- Pain in your side lower back
- Fever / loss of appetite/ feeling sick
- Haematuria (blood in the urine)
What is a descending UTI?
A rarer form of UTI where the UT becomes infected from bacteria in the blood (eg Staphylococci)
Which bacteria causes syphilis?
Treponema pallidum
What are the complications associated with chlamydia for adults and babies?
Adult: sterility, trachoma
Baby: premature birth, trachoma, pneumonia
What are the 4 symptoms of gonnorrhea and chlamydia?
Discharge
Pelvic pain
Infertility
Pain on urination
What are the complications associated with gonnorrhea for adults and babies?
Adults: sterility, systemic infection
Baby: trachoma →blindness
How is gonnorrhea treated?
Used to be 100% curable by penicillin
Now high levels of beta lactam resistance
Current PHE guidance:
- Ceftriaxone 1g IM or
- Ciprofloxacin 50mmg stat (if sensitivity known)
What is Caries?
A dental infection caused by Streptococcus mutans.
Grows on plaque on teeth, roduces Lactic acid and can cause tooth decay.
Treated with fillings/ extraction
What are dental abcesses?
Infection from tooth decay that spreads under the gum, can be treated with antibiotics but needs dental treament
What is peridontal disease?
Bacteroides/Actinomyces colonises between the teeth and gums. The gums bleed and receed, teeth may fall out. Can only be treated by better oral hygiene
Which bacteria causes oral thrush?
Candida albicans