Streptococcus Pneumoniae

Question 1

What shape is Strept. Pneum?

Answer 1

ROUND SHAPE in chains = COCCUS

Question 2

What gram stain and why?

Answer 2

Gram positive = thick peptidoglycan in cell wall

Question 3

What colour does positive gram stain?

Answer 3

PURPLE

Question 4

Strep Pneumonia is non-…. and non-….

Answer 4

Non-motile and non-sporing

Question 5

What kind of anaerobes are strep. Penumonia and what does that mean?

Answer 5

Facultative anaerobes = means they can survive in aerobic and non-aerobic conditions

Question 6

Is strep. pneumonia catalase positive or negative?

Answer 6

Catalase negative = NO CATALASE ENZYME

Question 7

What type of agar can be used for strep. pneumonia? Explain.

Answer 7

BLOOD AGAR - undergoes alpha hemolysis (green hemolysis) because it produced HYDROGEN PEROXIDE which partially oxidises red Hb&raquo_space; green methahemoglobing

Question 8

What is the OPTOCHIN TEST and how is it done?

Answer 8

It is a test used to distinguish strep. pneumonia from other strep. species (eg strep viridians)

Optochin is added to the blood agar = strep. pneumonia is sensitive to optochin and will die, whereas strep. viridian’s are resistant to optochin test and will survive

Question 9

Describe Ag on strep. pneumonia and which type of Ab is produced against it?

Answer 9

Ag = capsular pollysaccharide

• over 100 serotypes
• induce production of IgM Ab

Question 10

State the virulence factors of strep. pneumonia

Answer 10

• ENCAPSULATED:
• polysaccharide layer that is capsulated - contain pili + fibrin (allow attachment to surfaces) = capsule also INHIBIT PHAGOCYTOSIS
• TOXINS:
• IgA protease > destroys IgA antibody
• Pneumolysin > activates host complement system + causes local inflammation which destroys bacteria AND HOST TISSUE

-NEURAMINIDASE:
-glycoside hydrolase enzymes > cleave glycosidic linkages of neuraminic acids.
-contributes to a variety of perturbations =
>high viscosity of blood
>thrombocytopenia
>hemolytic anemia
>auto immune conditions
>deficiency of mucus viscoelasticity

Question 11

What type of immunity is induced against strep. pneumonia?

Answer 11

Hummoral Immunity

Protective opsonising Ab against capsular pollysaccharides

Question 12

What kind of infections does strep. pneumonia cause?

Answer 12

RHINOSINITIS
MENINGITIS
OTITIS MEDIA
PNEUMONIA
BACTERMIA

Question 13

What is RHINOSINITIS?

Answer 13

RHINOSINITIS:

> mucus membrane in nose + in paranasal sinus becomes inflammed&raquo_space; fever, headache + facial pain

Question 14

Describe MENGITIS?

Answer 14

MENINGITIS:
> when walls of paranasal sinus is very thing > strep. pneumonia can enter cranial cavity&raquo_space; fever, neck stiffness, headache

Question 15

Describe OTITIS MEDIA?

Answer 15

OTITIS MEDIA:
> strep. pneumonia invading eustachian tube = pain in ear
> chronic otitis media can radiate to mastoid behind ear + cause MASTOIDIS
> also enter cranial cavity from ear&raquo_space; MENINGITIS

Question 16

Describe PNEUMONIA?

Answer 16

PNEUMONIA:
> strep can adhere to alveola cells = pneumocytes and release pneumolysin > leads to destruction of pneumocytes and alveolar capillaries
> fever, chills, cough, chest pain

Question 17

What is BACTERAEMIA and what other infections can it lead to?

Answer 17

BACTERMIA:
> strep can enter alveolar - capillary wall + enter blood

> SEPSIS = common in people with spleen problems (splenectomy) and sickle cell disease

> PNEUMOCOCCO ENDOCARITIS: forms clums that damage the valves + infect pericardium

> SEPTIC ARTHIRITIS: strep collects in joints

> MENINGITIS: crosses blood-brain barrier

> BACTERIAL PERITONITIS: enters peritoneum > common in P with cirrhosis and develop ascites or too much fluid in peritoneal cavity

Question 18

How is strep. pneumonia diagnosed?

Answer 18

Biological specimens taken: 
>pus
>sputum
>CSF
>PERITONEAL FLUID

PCR > to detect strep. pneumonia DNA

Question 19

What staining can be used for strep. pneumonia?

Answer 19

KLETT STAINING
LOFFLER
GRAM

Question 20

Who is eligible to get vaccines against strep. pneumonia?

Answer 20

Vaccines given to those at risk:
> infants under 2 yrs
> elderly above 55yrs
> P with chronic diseases (diabetes, HIV, cancer, sickle cell disease, no or impaired spleen)

Question 21

What are types of vaccines for strep. pneumonia?

Answer 21

2 GROUPS OF VACCINES:

1) Pneumococcal Polysaccharide Vaccine (PPV23)
-contains 23 purified capsular Ag
> ADULTS

2)Pneumococcal Conjugate Vaccine (PCV13)
- capsular pollysaccharide specific to 13 strep. pneumonia serotypes
-bound to non-toxic recombinant of DIPHTERIA TOXINS
> YOUNG INFANTS

Question 22

State other prophylaxis for strep. pneumonia?

Answer 22

RESPIVAX

BRONCHOVAXOME

Question 23

What are the ANTIBIOTIC TREATMENT for strep. pneumonia?

Answer 23

BETA LACTAM (Anb)/ MACROLIDES/ CHLORAMPHENOL
> Penicillin G
> Penicilin V
> Cephalosporins

β-lactam antibiotics: antibiotics contain beta-lactam ring in molecular structure > includes penicillin derivatives (penams), cephalosporins (cephems), monobactams, carbapenems and carbacephems.

Question 24

As strep. pneumonia has progressively developed resistance to penicillin and its derivatives (amoxycillin + ampicillin), what other alternatives can be used?

Answer 24

> FLUROQUINOTONES

> COMBINATION (amoxicillin + clauvonic acid)

> 3rd generation cephalosporins (ceftriaxone + cefotaxine)

> vancomycin + linezolid