Microbiology Flashcards by Shamoun Dattu

What is the typical initial state of tuberculosis infection?

Asymptomatic, becomes latent in a Gohn focus/granuloma

Reactivation occurs due to factors like immunosuppression.

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What are classic lesions associated with tuberculosis?

Caseating granulomas

These granulomas are a hallmark of TB infection.

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List some risk factors for developing tuberculosis.

Travel to South Asia/Eastern Europe
HIV+
Homelessness
Intravenous drug use (IVDU)
Contact with infected individuals

These factors increase susceptibility to TB.

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What are the general presentations of tuberculosis?

Fever
Night sweats
Weight loss

These symptoms are common in active TB cases.

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What are respiratory symptoms associated with tuberculosis?

Cough
Haemoptysis

These symptoms indicate pulmonary involvement in TB.

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What are less common presentations of tuberculosis seen in immunosuppressed patients?

Subacute meningitis
Pott’s disease
Miliary TB
Lymphadenitis
Pericarditis
Peritonitis
Renal TB
Testicular TB
Liver TB

These presentations indicate disseminated or atypical forms of TB.

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What is the gold standard investigation for tuberculosis?

Culture on Lowenstein-Jensen medium for 6 weeks

Acid-fast bacilli can be identified through this method.

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What does a Tuberculin skin test (Mantoux/Heaf) indicate?

Exposure to tuberculosis (active/latent/BCG)

This test helps in identifying prior exposure to TB.

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What are the components of the RIPE treatment regimen for tuberculosis?

Rifampicin
Isoniazid
Pyrazinamide
Ethambutol

This combination is typically administered for 2 months, followed by rifampicin and isoniazid for an additional 4 months.

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What are some side effects of tuberculosis medications?

Rifampicin – orange secretions
Isoniazid – peripheral neuropathy
Pyrazinamide – hepatotoxicity
Ethambutol – optic neuritis

Awareness of these side effects is important for patient management.

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What is the purpose of BCG vaccination?

To provide immunity against tuberculosis in high-risk patients

BCG is a live attenuated vaccine derived from M. bovis.

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What are the main characteristics of leprosy?

Skin depigmentation
Nodules
Trophic ulcers
Nerve thickening

Leprosy is caused by M. Leprae and can lead to significant disability due to nerve damage.

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What does Mycobacterium Avium-Intracellulare complex resemble?

Tuberculosis, particularly in individuals with underlying lung disease

This complex often causes disseminated infections in immunocompromised patients.

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What is a common condition caused by Mycobacterium marinum?

Fish tank granuloma

This condition typically presents as papules or plaques in aquarium owners.

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What are the symptoms of Mycobacterium ulcerans infection?

Painless nodules
Ulceration
Scarring
Contractures

This infection is commonly found in tropical regions and can lead to significant tissue damage.

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What is pneumonia?

Inflammation of lung alveoli

Symptoms include fever, cough, shortness of breath, and pleuritic chest pain.

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What are the symptoms of pneumonia?

Fever, cough, shortness of breath, pleuritic chest pain

Patients often present feeling sick.

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What investigations are performed for pneumonia?

CXR, calculate CURB-65, sputum cultures, atypical screen

CXR typically shows abnormal findings.

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What is the supportive treatment for pneumonia?

Oxygen, fluids

Antibiotics are guided by CURB-65.

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Define lower respiratory tract infection (LRTI).

Broad term for lung infection, includes pneumonia, bronchitis, empyema, abscess

Can be viral or bacterial with no CXR changes.

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What is bronchitis?

Inflammation of medium-sized airways, mostly in smokers

Can be viral or bacterial with no CXR changes.

What is the treatment for bronchitis?

Bronchodilation, chest physiotherapy, +/- antibiotics

Antibiotics are not always necessary.

What are the classifications of pneumonia?

Community-acquired vs Hospital-acquired, Typical vs Atypical

Hospital-acquired pneumonia occurs after >48 hours of hospital admission.

What pathogens are associated with hospital-acquired pneumonia?

S. aureus, Klebsiella, Pseudomonas, Haemophilus

These pathogens are more common in hospital settings.

What characterizes typical pneumonia?

Classic signs and symptoms, classic CXR changes (i.e., consolidation), responds to penicillin antibiotics ## Footnote Typical pneumonia is often caused by common pathogens.

What characterizes atypical pneumonia?

No/atypical signs and symptoms, not in keeping with CXR, doesn’t respond to penicillin antibiotics ## Footnote May have extra-pulmonary features, such as hepatitis or hyponatraemia.

What is the most common pathogen causing typical pneumonia?

Streptococcus pneumoniae ## Footnote Associated with rusty-coloured sputum and lobar consolidation on CXR.

What are the microscopy findings for Streptococcus pneumoniae?

+ve diplococci ## Footnote Commonly identified in sputum samples.

What is Haemophilus influenzae associated with?

Smoking ## Footnote It is a common cause of pneumonia in smokers.

What is the microscopy finding for Staphylococcus aureus?

+ve cocci 'grape-bunch clusters' ## Footnote Often associated with recent viral infections.

What are the characteristics of Klebsiella pneumoniae?

Common in alcoholics and the elderly, associated with haemoptysis ## Footnote Identified as a -ve rod, enterobacter.

True or False: Atypical pneumonia is defined by the commonality of the pathogen.

False ## Footnote Some atypical pneumonias are common, but their presentation differs from typical pneumonia.

What is Haemophilus influenzae?

-ve cocco-bacilli ## Footnote Associated with smoking and COPD.

What is Staphylococcus aureus associated with?

Recent viral infection (post-influenza) ± cavitation on CXR ## Footnote +ve cocci 'grape-bunch clusters'.

What is Moraxella catarrhalis associated with?

Assoc. w/ smoking ## Footnote -ve cocci.

What organisms are associated with HIV-related immunosuppression?

P. jiroveci, TB, Cryptococcus neoformans ## Footnote These organisms are common opportunistic infections in HIV patients.

What encapsulated organisms are a concern after splenectomy?

H. influenzae, S. pneumoniae, N. meningitidis ## Footnote These bacteria are more likely to cause infections in patients without a spleen.

Which organisms are commonly associated with cystic fibrosis?

Pseudomonas aeruginosa, Burkholderia cepacia ## Footnote These bacteria are significant pathogens in the lungs of cystic fibrosis patients.

What organism is associated with neutropenia?

Aspergillus ## Footnote Neutropenic patients are at risk for fungal infections, particularly Aspergillus.

What does CXR show in typical pneumonia?

Consolidation ## Footnote Chest X-ray is a key diagnostic tool in identifying pneumonia.

What is the purpose of sputum MC&S?

To identify causative organisms in pneumonia ## Footnote Sputum microscopy, culture, and sensitivity testing help determine the specific pathogen.

What investigation should be considered if sputum is non-productive?

Broncho-alveolar lavage ## Footnote This procedure helps obtain samples from the lungs when sputum samples are insufficient.

What tests are included in an atypical pneumonia screen?

Legionella urine antigen, serum antibody tests for Chlamydia, Legionella ## Footnote These tests help identify atypical organisms that are hard to culture.

What does CURB-65 stand for?

Confusion, Urea >7, Respiratory Rate >30, Blood Pressure <90/60, Age ≥65 ## Footnote CURB-65 is a scoring system to assess the severity of pneumonia.

What antibiotics are effective against typical organisms in community-acquired pneumonia?

Penicillins ## Footnote While effective for typical organisms, penicillins do not cover atypical pathogens.

What is used to cover atypical organisms in pneumonia treatment?

Macrolides ## Footnote Macrolides are chosen to provide coverage against atypical bacteria.

What is the first line treatment for hospital-acquired pneumonia?

Ciprofloxacin + Vancomycin ## Footnote These antibiotics are often used as initial therapy according to trust guidelines.

What combination is used for severe hospital-acquired pneumonia?

Tazocin + Vancomycin ## Footnote This regimen is often employed when the pneumonia is severe.

What is the treatment for aspiration pneumonia?

Tazocin + Metronidazole ## Footnote This combination targets organisms typically found in the oral cavity that can cause aspiration pneumonia.