Microbiology Flashcards
What lesion do you see in TB?
Caseating granuloma
When TB multiples at pleural surface and involves lymph nodes
Ghon focus
When TB goes systematic?
Miliary TB - haematogenous spread
Ix for TB
CXR - upper lobe cavitation Sputum culture - bronchoaveolar lavage if needed PCR/NAAT on sputum culture Mantoux test Acid fast bacilli with Ziehl-Neelsen IGRA
What are the features of TB meningitis?
Weight loss Fever Night sweats Headache Stiff neck Photophobia Low GCS Focal neurological deficit
How to diagnose TB meningitis?
CT
LP
Tx of TB meningitis
12 months anti-TB medication and steriods
Manifestation of spinal TB
All the TB symptoms and back pain
Discitis leads to vertebral destruction + collapse
Iliopsoas abscess
Ix of spinal TB + Tx
MRI/CT + biopsy/aspirate + one year anti-TB tx
What kind of vaccine is the BCG?
Attenuated
What kind of strain does the BCG use?
M.bovis
Who cant have the BCG vaccine?
HIV patients
What causes leprosy?
M.leprae + M.lepromatosis
Manifestations of leprosy?
Skin : depigmentation that lacks sensation, macules, nodules, ulcers
Neuro: thickened nerves causing neuropathy
Eyes: iridocyclitis, keratitis
Bone: periositis aseptic necrosis
Types of leprosy
Paucibacillary –> Multibacillary
TT - tuberculoid BT - borderline tuberculoid BB - borderline BT - borderline lepromatous Lepromatous BT
Tx of leprosy
Rifampicin, dapsone, clofazimine
Tx of TB
Initiation phase: 8 weeks
- Rifampicin - hepatoxiticy and drug interactions
- Isoniazid - hepatoxicity + peripheral neuropathy
- Ethambutol - optic neuritis and visual disturbances
- Pyrazinamide - dont give to gout patients. hepatoxicity
- Pyrodixone (B6) - give to pregnant, alcoholics, HIV+, neuropathy patients
Continuation phase: 16 weeks
- Rifampicin
- Isoniazid
Tx of latent TB
6 months of isoniazid
Tx of resistant TB
mono - one drug only
MDRTB - RIF + INA
XDRTB - RIF + INA + injectables (amikacine) + quinolones
CURB65
Confusion Urea > 7 Resp rate >30 BP <90 65 - age +
Score more than 2+ = hospitalisation, more than 3+ = severe pneumonia
Types of pneumonia
CAP + HAP
Bronchopneumoniae
Lobar
Atypical - usually in the interstium so outside the alveoli
Red hepatisation
Liver-like appearance of the lung tissue due to exudate filling the air spaces. Day 3-5
Gray hepatisation
Happens after red hepatisation when the RBC in the exudate start to break down. Day 5-7
Reticular CXR ?
Atypical pneumonia
Organisms associated with pneumoniae
Typical:
Strep pneumoniae + Staph aureus + H. influenzae - K. pneumonia - M. catarrhalis -
Atypical: look for extrapulmonary features and weird CXR or no signs
Klebsiella Mycoplasma pneumonia Legionella pneumophilia Chlamydia pneumonia Chlamydia psittaci Bordatella pertussis TB
Legionella pneumophilia
Airconditioning, water towers, hepatitis, hyponatremia
Mycoplasma pneumonia
THINK COLD AGGLUTININ TEST JOINT PAIN SJS Erythema multiforme Systemic symptoms
Chlamydia psittaci
Birds
Strep pneumonia
Lobar pneumoniae
Rusty-coloured sputum
H.Influenzae
COPD and smokers
M.Catarrhalis
Smokers
S.Aureus
Think recent viral infection
K.pneumonia
Alcoholics
Old people
Haemoptysis
ok bmt, what is the treatment for CAP? (mild)
outpatient amoxicillin
If allergic/2nd line - erythomycin (macrolide)
Supportive care for pneumonia
O2 therapy (careful COPD patients - aim for 92%)
IV fluids
OBs
Tx for CAP (moderate)
Amoxicillin + Erthyromycin/clarithyromycin
Tx for atypical pneumonia
Macrolide/Tetracyline
AKA - clarithomycin + doxycycline (?)
Tx for HAP ?
Cipro + vancomycin
Tx for aspiration pneumonia
Cefuroxime + metro
Tx for s.aureus
Flucloxacillin
Tx for legionella pneumonia
Macrolide + rifampicin
Tx for MRSA pneumonia
Vancomycin
Tx for pseudomonas spp
Cipro + gentamicin
Reid index in chronic bronchitis
> 40%
Blue bloaters
Chronic bronchitis
What infections are patients with chronic bronchitis at risk of?
Chest:
- Viral
- Strep pneumonia
- M. Cattahalis
- H. influenzae
What kind of pneumonia would HIV patients get?
P. Jiroveci
TB
Cryptococcus neoformans
What kind of risk do patients with splenectomy
Encapsulated organisms:
- H.influenzae
- N.meningitiditis
- S.pneumonia
Which organism do cystic fibrosis patients get?
Pseudomonas aeruginosa
Which organism can cause bone marrow suppression?
Aspergillus + CMV
Tx of bronchitis
Bronchodilators
Physiotherapy
Antibiotics if secondary infection as well
Types of fungal infections
Superficial vs deep
Yeast vs mould
How to diagnose superficial fungal infection
wood’s lamp
Types of superficial fungal infection
Tinea - athletes foot, ringworm
Pityriasis - seborrhoeic dermatitis, t.vesicolour (weird depigmentation)
Types of deep fungal infections
Candida - esp immunocompromised
Aspergillus - allergy, pneumonia in immunocompromised
Cryptococcus - immunocompromised (meningitis)
How to diagnose deep candida infection?
Culture, antibodies, mannan
How to diagnose deep aspergillus infection ?
ELISA, PCR, beta-glucan test
How to diagnose deep crytococcus infection?
Crytococcal antigen in serum/CSF
How do you treat cryptococcus meningitis?
Amphotericin B
Which antifungal target cell membrane synthesis
Fluconazole
Which antifungal targets cell membrane integrity
Amphotericin
Which antifungal targets DNA synthesis
Flucytosine
Which antifungal targets cell wall
Caspofungin
What causes clostridium botulinum?
Canned/vacuum packed food esp honey and beans
How does clostridium botulinum affect the body? (Anaeorbic)
Blocks Ach release from peripheral nerves
Leads to descending paralysis (opposite of GBS)
What causes clostridium perfringens? (Anaerobic)
Reheated meat, super antigen enterotoxin
Leads to massive cytokine production by CD4
Acts on small bowel - think watery diarrhoea + cramps. Lasts 24 hours
What causes clostridium difficile? (Anaerobic)
2 exotoxins (A,B) Results in pseudomembranous colitis CAUSED BY ABX - meeeeeee ciproooo
Virulence factors in s.aureus
Protein A
Catalase
Coagulase +ve
Symptoms of s.aureus (aerobic) GI infection?
Persistent vomting and diarrohea. No blood
What would you see on the blood agar - s.aureus?
Beta haemolytic
Different types of E.Coli infections?
EPEC - infantile diarrhoea (Paeds)
EHEC - haemorrhagic
ETEC - Toxigenic, Traveller’s diarrhoea. Acts on jejeunum, heat labile LT, ST?
EIEC - Invasive dystentry
HUS - anaemia, thrombocytopenia and renal failure (0157:H7 toxin)
How to treat e.coli GI infections?
Self-limiting or use ciproflaxcilin
How to treat Clostridia (perfrigens, difficile, botulinum)
Antitoxin. Metro/vanc for difficile - PO
How to treat s.aureus GI infections?
Self-limiting
Different types of salmonella?
Typhi
Paratyphi
- Multiples in the peyers patches
- Slow onset fever + constipation with bradycardia
- Splenomegaly
- Rose spots
- Anaemia
- Leukopenia
Tx of salmonella
Cipro or Ceftriaxone
Where does shigella attack?
Distal ileum and colon causing mucousal inflammation
Symptoms of shigella?
Bloody diarrhoea
Fever
Pain
Caused by the shigella enterotoxin
da fuck is Yersinia entercolitis
Animals shitting in food or something
So bad - you get reactive arthritis, erythema nodosum, mesentric adenitis, enterocolitis, necrotising granulomas. Likes a cold environment 4 degrees
How do you tx shigella?
Avoid antibiotics. Use cipro if you have to
What is the mechanism in cholera?
increased cAMP opens Cl- channel at apical membrane of enterocytes –> efflux of Cl- to lumen. Lose a lot of water and electrolytes
Why would me and yaz have 3 day hx of diarrhoea in japan?
parahaemolyticus and you get it from undercooked seafood
Tx of vibrio 1parahaemolyticus
Doxycycline
Tx of vibrio cholera
supportive
What is vibrio vulnificus?
cellulitis in peeps that handle shellfish handlers
Fatal septiciaemia with D+V in HIV patients
What causes campylobacter jejuni?
drinking unpastuerised milk, food
First you get headache, fever and the you get the tummy pain and foul, bloody diarrhoea