Microbiology- (p35-44- TB, RTIs + STIs) Flashcards
What is the presentation of TB?
Cough +/- haemoptysis Fever (night sweats) Weight loss Malaise Ethnicity
How does post-primary TB present and in who?
In young adults ?Reactivation/re-infection Upper lobes affected May progress to cavitation Classic lesion- caseating granuloma Healing by fibrosis and calcification
How does primary TB present and in who?
Children, elderly, HIV
Multiplies at pleural surface
LN involvement
Classic lesion- granuloma (Langhan’s giant cells)
Can be asymptomatic
Can be miliary- progressive, disseminated haematogenous spread
Treatment for TB (First line and second line)?
1st Line: RIPE Rifampicin Isoniazid Pyrazinamide Ethambutol RI for 4 months PE for 2 months
2nd line:
Injectables (capreomycin, kanamycin, amikacin), quinolones, cycloserine, ethionamide, PAS etc
Investigations for TB?
Imaging- CXR (upper lobe cavitation in post-primary), CT
Culture- Sputum (x3), bronchoalveolar lavage, urine, pus etc in Lowenstein Jensen medium (Gold standard)
Sputum microscopy- ZN/auramine stain- Gram +ve rods, acid fast, aerobic, intracellular
Tuberculin skin tests- Mantoux/Heaf
Interferon gamma release assays
NAAT
How does TB meningitis present and how is it diagnosed?
Subacute Weight loss, fever, night sweats Headache, neck stiffness Personality change, decreased GCS Focal neurological deficit Diagnosis- CT or LP (lymphocytic)
Treatment for TB meningitis?
> 12 months of TB treatment and steroids
Types of extrapulmonary TB and who is at risk?
Lymphadenitis Pericarditis Abdominal Genito-urinary, renal, testicular Skin, liver etc
People at risk with HIV coinfection
Risk factors for TB and reactivation of latent TB?
Recent migration, HIV, homeless, drug users, prison, close contacts
Reactivation of latent:
Immunosuppression, malnutrition, ageing, chronic alcohol excess
Vaccination for TB?
BCG- attenuated strain of m. bovis
Manifestations of leprosy?
Skin- depigmentation, macules, plaques, nodules, trophic ulcers
Nerves- thickened nerves, sensory neuropathy
Eyes- Keratitis, iridocyclitis
Bone- periostitis, aseptic necrosis
Treatment for leprosy?
Rifampicin, dapsone, clofazimine
Other mycobacteria?
M. Avium
M. marinarum (fish tank granuloma)
M. ulcerans (insects- tropics/Aus)
Definition of pneumonia?
Inflammation of lung alveoli
Definition of bronchitis?
Inflammation of medium sized airways
Presentation of pneumonia
Fever, cough, pleuritic chest pain, SOB
Presentation of bronchitis?
Cough, fever, increased sputum production, increased SOB
Commonly smokers
What would the bronchitis CXR show?
Normal
How do you assess pneumonia severity?
CURB 65
Treatment of pneumonia?
Supportive (O2, fluids etc) and Abx
Treatment of bronchitis?
Bronchodilation, physiotherapy +/- Abx
What pathogen is associated with rusty coloured sputum and is normally lobar on CXR?
S. pneumonia
What would you see down the microscope for S. pneumonia?
+ve diplococci
What would you see down the microscope for H. influenza?
-ve cocco-bacilli
What would you see down the microscope for S. aureus?
+ve cocci grape bunch clusters
Which organism is associated with recent viral infection (e.g. influenza) +/- cavitation on CXR?
S. aureus
What would you see in the microscope for K. pneumonia?
-ve rod, enterobacter
Name 3 atypical pneumonias
Legionella pneumophilia
Mycoplasma pneumonia
Chlamydia pneumonia
Which organism is associated with travel, air conditioning, water towers, hepatitis and low Na?
Legionella pneumophilia
What symptoms do you see in mycoplasma pneumonia?
Systemic, joint pain, erythema multiforme
What would you associate with chalmydia psittaci?
Birds
Which pathogen causes whooping cough in unvaccinated (e.g. travelling community in EMQs)?
Bordatella pertussis
What pathogens cause respiratory tract infections in HIV?
P. jiroveci, TB, cryptococcus neoformans
What pathogens cause respiratory tract infections after bone marrow Tx?
Aspergillus + CMV
What pathogens cause respiratory tract infections post-splenectomy?
Encapsulated organisms- H. influenza, S. pneumonia + N. menigitidis
What pathogens cause respiratory tract infections in cystic fibrosis?
Pseudomonas aeruginosa, burkholderia cepacia (v high mortality)
How do you diagnose respiratory tract infections?
Urine antigen tests in severe CAP for s. pneumonia and legionella
Antibody tests- paired serum samples, most useful for those difficult to culture e.g. chlamydia, legionella)
Immunofluorescence- Antibody labelled with fluorescent dye- used in virology
What is the definition of hospital acquired pneumonia?
> 48h into hospital stay without previous infection
What abx do you use to treat a mild-moderate CAP?
Penicillin 1st line (amoxicillin) or macrolide if penicillin allergy for 5-7d
What abx do you use to treat a moderate-severe CAP?
Penicillin + macrolide (co-amoxiclav + clarithromycin) 2-3w
What abx do you use to treat atypical CAPs?
Use protein synth. Abx- Macrolide/tetracycline
What commonly used drug does clarithromycin interact with?
Warfarin
What is the first line treatment for HAP?
Ciprofloxacin +/- vancomycin
If no joy, bring in the piptazobactam
Special tx for legionella?
Macrolide + Rifampicin
Special tx for s. aureus?
Flucloxacillin
Special tx for pseudomonas spp.?
Piperacillin + tazobactam
or
Ciprofloxacin +/- gentamicin
Special tx for MRSA?
Vancomycin
Which STIs cause discharge?
Gonorrhoea Chlamydia Trichomonas Candida BV
What STIs cause ulceration?
Syphilis HSV LGV Chancroid Donovanosis
What STIs cause rashes and lumps
Genital warts- HPV
Molluscum contagiosum
Scabies
Pubic lice
What is most likely diagnosis if painful genital ulcers?
Herpes
What is most likely diagnosis if painless genital ulcers?
Syphillis
What would you see down the microscope in N. gonorrhoeae??
Intracellular gram -ve diplococci
What condition can gonorrhoea lead to in neonates?
Opthalmia neonatorum (neonatal conjuctivitis) if left untreated when transferred to child from birth canal
How is gonorrhoea diagnosed?
Urethral (95% sensitivity) or rectal (20% sensitivity) smears- culture from these is gold standard
Tx of gonorrhoea?
Ceftriaxione IM- 250mg single dose or cefixime PO- 400mg single dose
What can gonorrhoea and chlamydia lead to in women?
PID- most common cause of female infertility in europe
How is chlamydia diagnosed?
Nucleic acid amplication tests (NAATs) - gold standard
Tx of uncomplicated chlamydia?
Azythromycin- 1g stat Doxycycline- 100mg BD 7/7
What is lympho-granuloma venereum?
Lymphatic infection with chlamydia trachomatis
How is lympho-granuloma venereum treated?
Doxycycline for 21/7 100mg BD
What pathogen is responsible for syphillis and what would you see on microscopy?
Treponema pallidum- gram negative spirochaete
How is syphilis diagnosed?
Detection of antibody (RPR), real time PCR and microscopy
How does primary syphilis present?
Macule -> papule -> indurated painless genital ulcer appearing 1-12w following transmission
May persist 4-6wks. Regional adenopathy.
How does secondary syphilis present?
Systemic bacteraemia. Low grade fever, malaise, symmetrical, non-pruritic, maculo-papular rash on back, trunk, arms, legs, palms, soles, face
How does tertiary syphilis present?
Gumma (granuloma- 2-40y later
Cardiovascular- 10-30y later
Neurosyphilis (most common in HIV +ve)- 2-30y later
Treatment of syphilis?
Single dose IM benzathine penicillin
What pathogen causes chancroid?
Haemophillus ducreyi
How and where does chancroid usually present?
Tropical ulcer disease mainly in Africa + rare in UK
Multiple painful ulcers
How is chancroid diagnosed?
Culture (chocolate agar) + PCR
Where is donovanosis common?
Africa, India, Australian aboriginal communities
How does donovanosis present?
Large expanding ulcers starting as papule or nodule that breaks down
Beefy red appearance.
How is donovanosis diagnosed?
Giemsa stain of biopsy or tissue crush. Donovan bodies.
How is donovanosis treated?
Azithromycin
What enteric pathogens are spread through oro-anal contact?
Shigella, salmonella, giardia (protozoan), occasionally others (strongyloides)
What do you see down the microscope in trichomoniasis vaginalis?
Flagellated protozoan
How is trichomoniasis diagnosed?
Wet prep microscopy, PCR
How is trichomoniasis treated?
Metronidazole
What happens in bacterial vaginosis?
Abnormal vaginal flora, polymicrobial, decreased lactobacilli
Smelly discharge
How is BV diagnosed?
Microscopy of gram stain, raised pH, whiff test and clue cells
Symptoms of candidiasis?
White thick discharge, itching, soreness, redness, vulvovaginitis in women and balantis in men
How is candidiasis treated?
Topical or oral antifungals- e.g. clotrimazole or fluconazole
What causes molluscum contagiousum?
Pox virus
How does molluscum contagiosum present and spread in children vs adults?
Children- hands and faces, skin to skin contact
Adults- genital lesions, sexual contact
Treatment of molluscum contagiosum?
Cryotherapy- destructive
Cause of genital warts?
dsDNA HPV
How are genital warts diagnosed?
Examination- papular, planar, pedunculated, carpet, keratinised, pigmented
How are genital warts treated?
Podophyllotoxin solution or cream
Cryotherapy