Microbiology

Question 1

Phage encoded toxins

Answer 1

ABCDE
ShigA Like
        Botulinium
        Cholera
        Diphtheria
        Erythrogenic toxin of Pyogenes

Question 2

Obligate Anaerobes

Obligate Aerobes

Answer 2

Anerobes are Can’t Breathe Air (Clostridium Bacteroides Actinomyces ). Do NOT USE AMINOGLYCOSIDES
Aerobes are Nagging Pests that Must Breathe (Nocardia, Pseudomonas, Mycobacterium and Bacillus)

Question 3

Competent bacteria (AKA TRANSFORMATION), i.e. they can take up DNA from the environment are

Answer 3

SHiN
S.Pneumoniae
H.flu type b
Neisseria

Question 4

NADPH oxidase deficiency

Answer 4

AKA Chronic Granulomatous Disease
Recurrent infections with catalase + organisms S.aureus, Pseudomonas and Candida. These degrade limited H2o2

Catalase Pos are PLACESS organisms (Pseu, Listeria, Asperg, Candida, S.aureus, Serratia)

Question 5

Why catalase is pathogenic

Answer 5

Degrades peroxide before it can be acted on myeloperoxidase to microbicidal products

Question 6

Encapsulated Organisms

Answer 6

SHiN (Strep pneumo, Hflu, Neisseria- also catalase pos)

SKS (Salmonella, Klebsiella and GBS)

Question 7

Intracellular organisms

• Bacteria
• Fungi
• Protozoa

Answer 7

Bacteria:- Chlamydia, Legionella, Listeria, MycoBacterium, Neisseria, Nocardia, Rickettsia, Salmonella
Fungi:- Cryptococcus, Histoplasma, Pneumocystis
Protozoa:- Plasmodium, Toxo

Question 8

Listeria monocytogenes

Answer 8

• multiplies at 4 degrees
• immotile at 37 but tumbling motility at 22
• narrow zone of beta hemolysis like GBS agalactiae
• meat, unpasteurized milk, soft cheese, raw veggs
• facultative intracellular
• CMI
• spread during delivery or via placenta
• Pore forming Listeriolysinn O selectively activated in acidified phagosome, can lyse vacuole and escape

Question 9

Modes intracellular bacteria evade immune system

Answer 9

• Block fusion of phagosome with lysosome (Salmonella and Mycobacterium TB)
• Inhibit phagolysosome acidification (Mycobacterium TB)
• Escape from phagosome into cytosol (Listeria and Shigella)

Question 10

Bugs to remember:- Name the diseases, key given

1. PSEUDOmonas
2. SStrep PneuMOniae
3. PMS for Agalactiae

Answer 10

1. Pneumonia (Cystic Fibrosis), Sepsis, Ear (swimmers ear), UTI, Drug Use & Diabetes and Osteomyelitis. Others are wound/burn infections, hot tub folliculitis, malignant otitis externa in diabetes
2. MOPS (Meningitis, Otitis Media in children, Pneumoniae and Sepsis in sickle cell anemia and splenectomy and SINUSITIS)
3. PMS (Pneumonia Meningitis and Sepsis) give intrapartum penincillin

Question 11

There are four beta hemolytic bacteria

one note about pyogenes

Answer 11

Listeria, Staph, GAS (pyogenes), GBS (agalacticiae)

Pyogenes:- Pharyngitis and more commonly impetigo precedes glomerulonephritis. Pharyngitis likely is followed by scarlet fever. Antibodies to M protein help assess risk for rheumatic fever even though it enhances immune response to pyogenes

Question 12

Natural Colonizers/Flora

Nose, Skin, Oropharynx, Vagina, Spore in Soil, Spore not in soil

Answer 12

1. Nose (Staph aureus)
2. Skin (Epidermis)
3. Oropharynx (Viridans)
4. Vagina (agalactiae, screen 35-38 wks, hippurate test +ve)
5. Spore in soil (Anthrax, Perfingens, Tetani)
6. Spore not in soil (Cereus, Botulium, Burnetti)