BACTERIAL PATHOGENS

Question 1

STAPHYLOCOCCUS AURIES

Answer 1

• Nasal carriage in 50% people
• can cause bacteraemia, septicaemia, pneumonia and meningits.
• produces exoenzymes and toxins

Question 2

STAPHYLOCOCCUS EPIDERMIS

Answer 2

• opportunistic skin commensal pathogen
• causes infection in association with ‘foreign bodies’ eg intravascular catheters. adheres to plastics/metals using glycocalyx (slime).
• slower acting than auries. high temp and pain.

Question 3

STREPTOCOCCUS PYOGENES

Answer 3

• group A strep.
• commonest cause of bacterial sore throat.
• causes scarlet fever (strawberry tongue), pneumonia
• gram positive

Question 4

STREPTOCOCCUS PNEUMONIAE

Answer 4

• commonest cause of bacterial pneumonia

- commonest cause of bacterial meningitis (except in neonates)

Question 5

STREPTOCOCCUS AGALACTIA

Answer 5

• group B strep

- commonest cause of bacterial meningitis and sepsis in neonates

Question 6

STREPTOCOCCUS MILLERI COMPLEX

Answer 6

• 3 closely related species of pus forming cocci.

- associated with abscesses e.g dental

Question 7

VIRIDENS STREPTOCOCCI

Answer 7

• a- haemolytic streptococci inhabit upper resp. tract.

- cause sub-acute bacterial endocarditis

Question 8

STREPTOCOCCUS GALLOLYTICUS

Answer 8

• (former name S.BOVIS)
• a-haemolytic strep that forms part of normal bowel flora.
• bacteraemia of this –> colonic malignancies

Question 9

LISTERA MONOCYTOGENES

Answer 9

• gram +ve , Zoonosis
• rare cause of sepsis and meningitis in pregnancy, neonates and the immunosupressed.
• associated with unpasteurised milk

Question 10

CORYNEBACTERIUM species

Answer 10

• gram +ve
• opportunistic infections with trauma and devices
• eg corynebacterium diptheria

Question 11

PROPIONIBACTERIUM acnes

Answer 11

• gram +ve
• associated with acne
• device associated and post-procedural infecitons

Question 12

ENTEROBACTERIACEAE

Answer 12

• gram -ve found in bowel flora
• e.g E.COLI which is commonest cause of UTI and bacteraemia.
• source of nosocomial (health-care) infections
• colonise shorter urethra in females and can develop antibiotic resistance.

Question 13

PSUDOMONAS AERUGINOSA

Answer 13

• gram -ve multi resistant.
• opportunistic: causes resp infections, UTI
• GREEN PIGMENT

Question 14

NEISSERIA MENINGITIS

Answer 14

• gram -ve
• causes meningococcal sepsis/ meningitis
• classic purpuric non-blanching rash

Question 15

NEISSERIA GONORRHOEAE

Answer 15

• gram -ve : cause of gonorrhora

- rare to cause invasive infections 2ndary to primary STI.

Question 16

-HAEMOPHILLUS influenzae

Answer 16

• gram -ve
• forms normal resp.tract flora and infections eg pneuonia
• type b (capsulated) causes meningitis and epiglottitis. only type b prevented by Hib vaccine.

Question 17

HACEK organisms

Answer 17

• unusual cause of infective endocarditis
• Haemophilus parainfluenzae,
• Haemophilus aphrophilus,
• Actinobacillus actinomycetemcomitans,
• Cardiobacterium hominis,
• Eikenella corrodens, and Kingella kingae.

Question 18

SPIROCHETES

Answer 18

• Treponemaa pallidium –> syphilis

- other species cause leptospirosis and lyme disease

Question 19

Cell-wall free

Answer 19

• MYCOPLASMA PNEUMONIAE
• LEGIONELLA PNEUMONIAE
• C. TRACHOMATIS (chalmydia species and commonest STI)

Question 20

ANAEROBES

Answer 20

• Bcteriodes fragilis

- e.g clostridium species: C.dofficile, C.tetani, C.botulinum

Question 21

MYCOBACTERIA

Answer 21

• AFB acid fast bacilli
  dont stain conventionally ie gram
  Mycobacterium tuberculosis –> tb
  others are opportunistic in AIDS patients