Clinical features of different bacteria Flashcards
Appearance of staphylococcus on microscopy
Clusters of cocci (bunch of grapes)
Tests used to differentiate between staphylococcus aureus and other staphylococcus strains
Coagulase test = positive
DNase test = positive
Surface protein A is present
Exotoxins produced by staphylococcus aureus
Toxic Shock Syndrome toxin
Enterotoxins A-E
Epidermolytic toxin (scalded skin syndrome)
Which bacteria can cause toxic shock and which test can be used to differentiate between them
Group A streptococcus (pyogenes) and staphylococcus aureus - GAS is catalase negative, Staph A is catalase positive
What kind of bacteria is listeria?
A gram positive, bacillus, facultative anaerobe, beta haemolysis on agar, intracellular pathogen (hides within phagocytic cells), produces flagella at room temp
Signs and symptoms of listeriosis
Flu-like illness, high fever, diarrhoea
Incidence of listeriosis
1 in 10,000
Neonatal mortality rate with listeriosis
Up to 60%
Transmission of listeria
Undercooked food, unpasteurised milk, soft cheeses, pate
What kind of bacteria is E.coli?
Gram negative rod, a non-lactose fermenter, facultative anaerobe
What are the microbiological characteristics of neiserria species?
Gram negative, diplococci, obligate aerobes, oxidase and catalase positive, often require a rich media to grow and thrive in the presence of high CO2
What levels of CO2 do Neisseria species prefer to grow in?
High levels
What does Treponema pallidum pertenue cause?
Yaws - (Yaw(n)s around the mouth) periositis, yellow papillomatous skin lesions
What is Yaws disease?
Disease caused by treponea pallidum pertenue = periositis, yellow papillomatous skin lesions
What does Treponema carrateum cause?
Pinta - (“tinta” of the skin) - achromic lesions and papulosquamous skin lesions
What is Pinta disease?
Caused by treponema carrateum - (“tinta” of the skin) - achromic lesions and papulosquamous skin lesions
What is Bejel disease?
Caused by terponema pallidum endemicum - oral mucosal lesions, mucus patches, condylomata lata, gummas
What does Treponema pallidum endemicum cause?
Bejel diseased - (“tinta” of the skin) - achromic lesions and papulosquamous skin lesions
What does Treponema pallidum pallidum cause?
Syphyllis
What are the features of congenital syphyllis?
Stillbirth
Before 2 years - maculopapular rash on hands and feet, snuffles, hepatosplenomegaly, optic neuritis
after 2 years - saber shins, saddle shaped nose, hearing loss, Hutchinson teeth (notches in teeth)
What are the features of primary syphilis?
1-3 weeks - painless chancre
What are the features of secondary syphillis
6-12 weeks - highly infectious, generalised lymphadenopathy, non-itchy maculopapular rash on body, condyloma lata
What are condyloma lata?
White, smoth, warty painless lumps around the genitals and anus that form during secondary syphillis
What are the features of tertiary syphilis?
Neuro - tabes dorsalis (posterior spinal column - loss of vibration and proprioception), anterior spinal column ( loss of sensation + weakness), neuro (altered mental state, memory loss, slurred speech, loss of coordination), CVs (aortic aneurysm), eye (aryll Robertson pupil), gumma
What is tabes dorsalis?
Damage to the posterior spinal cord (occurs in tertiary syphilis) - results in loss of proprioception and vibration sense
What is a Gumma?
Seen in tertiary syphilis - a ball of immune cells, surrounded by fibroblasts, with a necrotic centre which forms as an inflammatory response to the spirochaetes
What type of hypersensitivity reaction is tertiary syphilis?
Type 4 (T cell mediated)
What are the features of an Argyll Robertson pupil?
Accomodates but does not react to light (prostitutes pupil - seen in tertiary syphilis)
A-Which organism causes gas gangrene?
B- Which organism causes necrotising fasciitis?
C- most common cause of surgical site infection?
Clostridium perfringens
Streptococcus pyogenes
Staphylococcus aureus
Which bacteria are commonly found in breast abscesses?
Actinomyces and bacteroides
Which group of patients does a campylobacter jejuni infection typically effect?
Children and young adults
What disease does campylobacter jejuni typically cause?
Colitis (food poisoning)
What kind of bacteria is campylobacter jejuni?
Helical shaped, gram negative
What is the most common source of campylobacter jejuni?
Infected food or water (typically from infected faeces of domestic or farm animals)
Which antibiotics are effective against campylobacter jejuni?
Ciprofloxacin and erythromycin
