Bacteria and Symptoms Flashcards
Which bacteria causes TB?
Mycobacteria tuberculosis
What are the features of mycobacteria tuberculosis?
Slow growing, obligate aerobic bacteria.
Acid-fast bacilli (AFB)
Which stains can be used for mycobacterium tuberculosis? What medium is it grown on?
Acid-fast bacilli (AFB) which stains with Ziehl-Neelsen and auramine-rhodamine stain.
Traditionally grown on Lowenstein-Jensen media.
What are the signs/symptoms of TB?
Systemic features include weight loss and night sweats.
Pulmonary features of tuberculosis include cough and haemoptysis.
Extra-pulmonary abscesses can form and bone infection may occur (spinal TB = Pott’s disease).
Erythema nodosum may occur in TB and tuberculous meningitis can develop.
What is the cause of meningococcal meningitis?
Neisseria meningitidis bacteria
What are the features of neisseria meningitidis?
Also called meningococcus.
Gram NEGATIVE diplicocci. Catalase and oxidase +ve.
What are signs/symptoms of meningococcal meningitis?
Meningitis - headache, nausea, vomiting, pyrexia, photophobia.
Kernig sign +ve and neck stiffness.
What is the rash like in septicaemia caused by meningitis?
Purpuric non-blancing rash.
What is the cause of staph infections?
Staphyloccocus aureus at site or disseminated disease e.g. septicaemia.
What are the features of staph. aureus? What is its pattern of growth? Is it coagulase +ve or -ve?
Gram positive.
Grows in clusters and colonies appear yellow/golden on medium. Shows beta-haemolysis of blood agar medium. Coagulase +ve.
What are the signs/symptoms of staph infection?
MRSA= methicillin resistant staphylococcus aureus.
Not multi-resistant.
Resistance to penicillins by beta-lactamases.
Can cause pneumonia post-influenza.
What is the most common cause of pneumonia?
Streptococcus pneumoniae
What are the features of streptococcus pneumoniae?
Also called pneumococcus. Alpha-haemolytic Gram positive diplicocci. Oxidase +ve, catalase –ve. Grow in chains or pairs.
What is the periodicity of mycoplasma pneumoniae?
Occurs in 3-4 year cycles
What is the most common cause of atypical pneumonia?
Mycoplasma pneumoniae
What are the features of mycoplasma pneumoniae? Which medium does it grow on?
Intracellular bacteria which lacks complete cell wall.
Cold agglutinins +ve on blood test (50-70%), grows on Eaton’s agar.
What are the signs/symptoms of atypical pnuemonia?
Headache and malaise precede pulmonary features.
Host of extra-pulmonary features e.g. myocarditis.
What colour is the sputum in streptococcus pneumonia infection?
Productive cough (rusty coloured spututm), dyspnoea, pyrexia.
What is the colour of sputum in haemophilus pneumonia?
Yellow/green productive cough.
What are the features of haemophilus influenzae bacteria?
Gram negative bacilli
Which bacteria causes pneumonia in COPD commonly?
Haemophilus influenzae
Name 3 causes of atypical pneumonia.
- Mycoplasma pneumoniae
- Chlamydia pneumoniae
- Legionella pneumophila
Other:
- Chlamydophila psittaci
- Coxiella burnetii
- Viral pneumonias: SARS, RSV, adenonviridae, chickenpox pneumonitis.
Which bacteria causes pneumonia in cystic fibrosis and neutropenic states?
Pseudomonas aeuroginosa infects in CF, neutropenic states e.g. cytotoxic chemotherapy.
Describe the features of pseudomonas aeuroginosa. What does it produce in culture?
Gram negative bacilli
Produces green pigment (pyoverdin) in culture.
Which patients are most likely to develop pneumonia due to Klebsiella spp.?
Elderly pt with heart or lung disease
Diabetics
Alcoholics
Cancer patients
What are the features of Klebsiella spp?
Gram negative bacilli
Describe the sputum in Klebsiella pneumonia.
Purulent or blood stained sputum. Can be gelatinous.
Which patients get PCP (pneumocystic carinii pneumonia?
Immunocompromised
What is the new name given to pneumocystis carinii?
Pneumocystis jirovecii
What are the signs/symptoms of penumocytis jirovecii pneumonia?
Fever, marked dyspnoea (out of proportion from CXR findings), non-productive cough.
Which bacteria causes Legionnaire’s disease?
Legionella pneumophila
Which pneumonia-causing bacteria is associated with water source/poor ventilation?
Legionella pneumophilia
What are the features of legionella pneumophilia?
Gram negative aerobic bacilli.
Catalse, oxidase, beta-lactamase +ve.
What are the features of streptococcus viridans?
Alpha-haemolytic and differentiated from Streptococcus pneumoniae by optochin test.
Which test differentiates between streptococcus pneumonia and streptococcus viridans?
Optochin test
Which bacteria causes group A strep infections like strep throat?
streptococcus pyogenes
Name 3 types of infection caused by streptococcus pyogenes.
Strep throat
Endocarditis
Scarlet fever
What are the features of streptococcus pyogenes? What is elevated when infected?
Beta-haemolytic streptococcus with group A antigen.
Elevated anti-streptolysin A titre following infection.
What is a possible consequence of strep throat?
Strep throat can lead to rheumatic fever via immune reaction.
What are the signs/symptoms of scarlet fever?
Fever, rigors, headache vomiting and lymphadenopathy.
Blanching eythematous rash.
Strawberry tongue then raspberry tongue.
Which bacteria causes shigella dysentery?
Shigella flexineri
How is shigella flexineri transmitted?
Faeco-oral route
What are the features of shigella flexineri?
Gram negative with four serotypes.
What is a symptom of shigella dysentery infection?
Frequent small volume stools with blood and mucus.
Which bacteria causes Letospirosis?
Leptospira interrogans
How is Letospirosis contracted?
Spirochete zoonosis.
Ingestion of infected water.
What are the signs/symptoms of Letospirosis?
Jaundice and haemorrhage. Severe headache, malaise, fever, anorexia and myalgia.
Which bacteria causes Lyme disease?
Borrelia bugdorferi
What are the signs/symptoms of Lyme disease?
Initially skin lesions and headache, myalgia, arthralgia.
Second stage month later with neurological features.
What is a common cause of hospital acquired diarrhoea?
Clostridium difficile
What toxins are produced by c. difficile? How are they detected?
Produces two major toxins toxin A (enterotoxic) and B (cytotoxic).
ELISA for toxins as diagnostic tool.
What are the features of c. difficile bacteria?
Gram positive anaerobic bacilli.
What is the main cause of C. difficile diarrhoea? What is a possible consequence?
Disruption to normal commensals in the gut by broad spectrum antibiotics (e.g. co-amoxiclav) can cause overgrowth.
May lead to pseudomembranous colitis.
Which bacteria causes Leprosy(Hansen’s disease)?
Mycobacterium leprae
What are the features of myobacterium leprae?
Gram positive aerobic rod.
Does not grow in culture.
What are the signs/symptoms of leprosy?
Anaesthetic skin lesions.
Peripheral nerve damage.
Which bacteria causes gastroenteritis?
Campylobacter jejuni
How is campylobacter jejuni transmitted?
Zoonotic infection.
Bowel commensal in many livestock
What are the signs/symptoms of gastroenteritis? How does it differ from salmonella infection?
Crampy abdominal pains, nausea and profuse diarrohaea, sometimes blood stained.
Longer incubation than salmonella.
Which bacteria cause salmonella?(2)
Salmonella enteritidis
Salmonella typhimurium
What are the features of salmonella bacteria? Which medium can be used to grow it?
Gram negative
MacConkey agar plates- hints towards enterococci.
Incubation 12-48 hours.
What are the signs/symptoms of salmonella?
Crampy abdominal pains, nausea, diarrohea and occasional fever.
What infections does esterichia coliform commonly cause?
Gastroeneritis
UTI
Which form of esterichia coliform is enterotoxic?
Commensal forms are not pathogenic. Enterotoxic forms include 0157:H7
What bacteria cause typhoid/enteric fever?
Salmonella typhi
Also Salmonella paratyphi
How is typhoid contracted?
Faeco-oral contact
What are the features of salmonella typhi? Which medium does it grow on?
Gram negative
MacConkey agar plates
What are the signs/symptoms of typhoid?
Onset non-specific; intermittent fever, headache and abdo pain.
Abdominal tenderness, hepatosplenomegaly, lymphadenopathy and maculopapular rash.
List some complications of typhoid.
Complications include meningitis, pneumonia, bone infections and perforation.
Which bacteria causes Q fever?
Coxiella burnetii
What are the signs/symptoms of Q fever?
Fever, malaise, headache with multiple lesions on CXR.
