Microbiology- (p35-44- TB, RTIs + STIs) Flashcards by Greg Poyser

What is the presentation of TB?

Cough +/- haemoptysis
Fever (night sweats)
Weight loss
Malaise
Ethnicity

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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

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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

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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

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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

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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)

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Treatment for TB meningitis?

> 12 months of TB treatment and steroids

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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

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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

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Vaccination for TB?

BCG- attenuated strain of m. bovis

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Manifestations of leprosy?

Skin- depigmentation, macules, plaques, nodules, trophic ulcers
Nerves- thickened nerves, sensory neuropathy
Eyes- Keratitis, iridocyclitis
Bone- periostitis, aseptic necrosis

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Treatment for leprosy?

Rifampicin, dapsone, clofazimine

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Other mycobacteria?

M. Avium
M. marinarum (fish tank granuloma)
M. ulcerans (insects- tropics/Aus)

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Definition of pneumonia?

Inflammation of lung alveoli

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Definition of bronchitis?

Inflammation of medium sized airways

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Presentation of pneumonia

Fever, cough, pleuritic chest pain, SOB

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Presentation of bronchitis?

Cough, fever, increased sputum production, increased SOB

Commonly smokers

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What would the bronchitis CXR show?

Normal

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How do you assess pneumonia severity?

CURB 65

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Treatment of pneumonia?

Supportive (O2, fluids etc) and Abx

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Treatment of bronchitis?

Bronchodilation, physiotherapy +/- Abx

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What pathogen is associated with rusty coloured sputum and is normally lobar on CXR?

S. pneumonia

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What would you see down the microscope for S. pneumonia?

+ve diplococci

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What would you see down the microscope for H. influenza?

-ve cocco-bacilli

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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