*Microbiology 2 (Lecture 2) Flashcards Preview

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Flashcards in *Microbiology 2 (Lecture 2) Deck (77):
1

What are the causes of the classical flu?

Influenza A virus
Influenza B virus

2

What is the cause of a flu like illness?

Parainfluenza viruses but many other causes

3

Does haemophilus influenzae cause flu?

Not a primary cause (it is a bacterium) but may be a secondary invader

4

Complications of flu?

Primary influenzal pneumonia
Secondary bacterial pneumonia
Bronchitis
Otitis media
Influenza during pregnancy may also be associated with perinatal mortality, prematurity, smaller neonatal size and lower birth weight

5

How is flu treated?

Symptomatic (bed rest, fluids, paracetamol)
Antivirals (only if patient is at risk of complications and when flu is circulating and early in disease)

6

What antivirals are used to treat flu?

Oseltamivir
Zanamivir

7

What are epidemics of flu associated with?

Winter
Minor mutations in the surface proteins of the virus (antigenic drift)

8

What is the difference between epidemic and pandemic?

An epidemic occurs when a disease affects a greater number people than is usual for the locality or one that spreads to areas not usually associated with the disease. A pandemic is an epidemic of world-wide proportions.

9

What type of flu can cause pandemics?

Influenza A only

10

What subtype of influenza A is avian flu?

H5N1

11

How is influenza confirmed in the lab?

Direct detection of virus:
PCR (nasopharyngeal swab, throat swab or other respiratory samples)
Other labs/ hospitals may used immunofluorescence, antigen detection (near patient)

12

Prevention of flu?

Killed vaccine (given to adult/ child (aged 6 months to 2 years) patients at high risk and healthy care workers)
Live attenuated vaccine (more effective than killed vaccine in children aged 2-17, given to ALL children aged 2-5 and all primary school children administer intra-nasally)

13

When are antivirals used as a prophylaxis against flu?

After a contact with flu
Very rarely

14

What are 3 examples of atypical pneumonia?
How are these treated?

Mycoplasma pneumoniae
Coxiella and Chlamydohila psittaci
Tetracycline and macrocodes e.g. clarithromycin

15

Mortality of atypical pneumonias?

Varies with pathogen by generally lower than classical bacterial pneumonia

16

How are the atypical pneumonias (mycoplasma, coxiella, psittaci) diagnosed?

By serology (send acute and convalescent bloods to lab)
Virus detection (PCR on respiratory swabs/ secretions)

17

Who tends to get mycoplasma pneumoniae?

Children and young adults
Person to person spread

18

What diseases does coxiella burnetti cause?

Pneumonia
Q-fever

19

what is infection with coxiella burnetti associated with?

Sheep and goats

20

Complications of infection wit coxiella burnetti?

Culture negative endocarditis

21

What illness does infection with chlamoydophila psittaci cause?
How does this usually present?

Psittacosis (parrot fever)
Pneumonia

22

What age do patients present with bronchiolitis?
Symptoms

1st or 2nd year of life
Fever
Coryza
Cough
Wheeze
Severe cases can cause grunting, decreased PaO2, intercostal/ sternal indrawing

23

Complications of bronchiolitis?

Respiratory and cardiac failure
(especially if premature or pre-existing conditions)

24

What is usually the cause of Bronchiolitis?
How is this confirmed?

Respiratory Syncytial Virus
By PCR on throat or perusal swab

25

Therapy for bronchiolitis?

Supportive

26

What is metapneumovirus?

A respiratory viral pathogen that causes acute respiratory tract infection in children
Most children have antibody by age 5

27

What diseases does metapneumovirus cause?

Second only to RSV in bronchiolitis
2% of cases pf influenza-like illness
Ranges in severity from mild to requiring ventilation

28

How is metapneumovirus confirmed in the lab?

PCR

29

what is a cause of infantile pneumonia related to an STI?
How is it diagnosed?

Chlamydia trachomatis
PCR on urine of mother or perusal/ throat swabs of child

30

What does chlamoydophila pneumonias cause?

Mostly mild respiratory infeciton
Person to person spread

31

What is the upper respiratory tract colonised with?

Gram positives:
Alpha-haemolytic streptococci inc. strep pneumoniae
B-haemolytic streptococci inc. strep pyogenes
Staph aureus
Gram negatives:
Haemophilus influenzae
Moraxella catharalis
Many others

32

What are the 5 types of upper respiratory tract infections

Sinusitis
Rhinitis
Pharyngitis (includes pharynx, tonsils and uvula)
Epiglottitis
Laryngitis

33

What usually causes epiglottitis/

Haemophilus influenzae type B

34

Clinical picture of epiglottitis?

Children (2-7):
Acute onset (hours)
Sore throat
Drooling
sevre croup/ stridor
High temp
Adult onset is days

35

How do we test for epiglottitis?

Blood culture

36

Why do we not test for epiglottis using a throat swab?

It can irritate the epiglottis further causing it to swell up further

37

Treatment for epiglottis?

Usually admitted to ICU and treated with Ceftriaxone

38

Are the conducting airways (trachea and bronchi) usually colonised?

No

39

When do patients tends to get infection in their conducting airways (trachea and bronchi)?

Changes to airway e.g. trauma/ intubation
Airway abnormalities
Virulent pathogen

40

What are the pathogenic causes of acute COPD exacerbation?

Can be environmental
Haemophilus influenzae
Moraxella catarrhalis
Streptococcus pneumoniae
Gram negatives
Virus

41

Why do patients with CF tend to get frequent infections?

Inefficient clearance and build-up of mucus

42

What types of bacteria are often seen in CF patients?

Staph aureus. haemophilus influenzae, strep pneumoniae, pseudomonas aeruginosa, Burkholderia cepacia and MANY others

43

What is whooping cough (pertussis)?

Acute tracheobronchitis

44

What are the clinical features of whopping cough (pertussis)

Cold like symptoms for 2 weeks
Paroxysmal coughing
Repeated voilent exhalations with severe inspiratory whoop, vomiting common
Residual cough for month or more

45

What bacteria causes whooping cough?

Bordetella pertussis (gram negative coccobacillus)

46

How is pertussis diagnosed?

Bacterial culture (pernasal swab)
PCR (pernasal swab)
Serology

47

Treatment of pertussis?

Antibiotics if had cough for less than 21 days - clarithromycin (erythromycin if pregnant)

48

Clinical features of CAP?

Cough
Increased sputum
Chest pain
Dyspnoea
Fever
CXR with infiltrates
Acquired in the community

49

Is legionella gram negative or gram positive?

Gram negative

50

Clinical features of legionella pneumonia?

Flu like illness which may progress to severe pneumonia, with mental confusion, acute renal failure and GI symptoms

51

How is legionella pneumonia spread?

No person to person spread
Inhalation of contaminated water droplets
Therefore associated with shower heads, cooling towers, air conditioning

52

Diagnosis of legionella pneumonia?

Legionella urinary antigen (detects serogroup 1 only)
PCR available direct from sputum

53

Treatment of legionella pneumonia?

Clarythromycin, erythromycin, levofloxacin

54

What is the greatest risk for developing hospital acquired pneumonia?

Endotracheal intubation with mechanical ventilation (also risks with sedation, micro aspirations, aspirations of GI contents, immunosuppression)

55

Microbiology of HAP?

60% = gram negative including E. coli, Klebsiella spp, pseudomonas app, CAP organisms, S aureus and anaerobes

56

Treatment of a severe HAP?

IV amoxicillin, metronidazole and gentamicin
Step down to PO co-trimoxazole + metronidazole

57

Treatment of non-severe HAP?

PO amoxicillin + metronidazole

58

What is the full name of PCP?

Pneumocystis jirovecii pneumonia

59

What type of patients get this?

One of the most frequent and severe opportunistic infection in people with weakened immune systems e.g. aIDS, immunosuppression (people with a normal immune system can be asymptomatic with it either carrying it or eradication it)

60

What type of organism is pneumocystitis jirovecii?

Fungus

61

Does mycoplasma pneumonia cause a dry or wet cough?

Dry

62

Symptoms of PCP?

Fever
Dry cough
SOB
Fatigue
HIV patients = sub-acute, low grade fever, severe pneumonia
Non-HIV = more acute high fever

63

Diagnosis of PCP?

Microscopy (immunofluorescence of gargle)
PCR

64

Treatment of PCP?

Co-trimoxazole or pentamdine

65

What are a list of causes of CAP?

Streptococcus pneumonia (Common)
Haemophilus pneumoniae (common)
Moraxella catarrhalis (common)
Mycoplasma pneumonie (common, atypical)
Chlamydias (pneumoniae (atypical), psiticci (atypical), trachomatis)
PCP
Legionella pneumoniae (atypical)
Staphylococcus aureus
Coxiella burnetti (atypical)
Viruses

66

Aside from PCP, what is another fungal chest infection?

Apergillus

67

What causes aspergilus chest infection?

Usually aspergillum fumigates (common environmental fungus)

68

What type of patients get aspergillus chest infection?

Immunocompromised/ supressed patients
(causes severe pneumonia and invasive disease)

69

What type of infection do immunocompetent patients infected by aspergillus get?

Localised pulmonary infection
Aspergilloma (fungus ball) in pre-existing chest caivties

70

How is aspergillus diagnosed?

Bronchoalveolar lavage ideally (fungal culture, PCR)
Tissue (histopathology)

71

Treatment of aspergillus?

Amphotericin B
Voriconazole
Surgery

72

Causes of TB?
Appearance of TB?

Mycobacterium tuberculosis
Acid alcohol fast bacilli with a thick waxy coat

73

Pathogensis of TB?

Mycobacterium tuberculosis are engulfed by alveolar macrophages in alveoli but resist killing and multiply leading to a focus

74

Types of TB?

90% asymptomatic and develop latent TB (alterations in immune function leads to reactivation and active TB)
10% develop immediate active TB

75

Clinical symptoms of TB?

Long term cough
Chest pain
Sputum =?- haemoptysis
Weakness or fatigue
Fever and chills
Night sweats

76

Diagnosis of TB?

Microscopy of sputum/ tissue
Culture on selective media
PCR
Immune reaction

77

How is microscopy of mycobacterium tuberculosis prepared?

Ziehl-Neelsen (ZN) stain is used - red dye which is added to smear and heated to allow dye to penetrate waxy coat, acid/alcohol added
Waxy coat of mycobacterium retains the dye even after exposure to acid and alcohol