Bacteria Basics & IDs

Question 1

Gram Negative Circular Cocci:

Maltose fermenter vs. Nonfermenter?

Answer 1

Maltose Fermenter: N. meningitidis

Maltose Nonfermenter: N. gonorrhoeae

Question 2

Gram Negative “Coccoid” Rods?

Answer 2

• Haemophilus influenzae (requires factors V & X)
• Pasteurella - animal bites
• Brucella - brucellosis
• Bordetella pertussis

“Italian Foods - Pasta, Bruschetta, Bordetella”
“ATE the FOOD” (H. flu)

Question 3

Gram Negative Enterics, Oxidase positive, Comma-shaped:

Grows in 42 deg C vs. Alkaline Media?

Answer 3

42 deg C = Campylobacter jejuni

Alkaline media = Vibrio cholerae

Question 4

Gram Negative Rods:

Latose fermenter - fast vs. slow?

Answer 4

Fast fermenters = Klebsiella, E. coli, Enterobacter

Slow fermenters = Citrobacter, Serratia

Question 5

Gram Negative Rods:

Lactose Nonfermenters - Oxidase pos vs. neg?

Answer 5

Oxidase positive = Pseudomonas, H. pylori

Oxidase negative = Shigella, Salmonella, Proteus

Question 6

Gram Positive, Branching filamentous:

Anaerobe vs. Aerobes?

Answer 6

Anaerobe (not acid fast) = Actinomyces

Aerobe (acid fast) = Nocardia

Question 7

Gram Positive Rods (bacilli)?

Answer 7

• Clostridium (anaerobe)
• Corynobacterium
• Listeria
• Bacillus (aerobe)
• Mycobacterium (acid-fast)

Question 8

Gram Positive Cocci – Catalase positive (clusters);

Coagulase pos vs. neg?

Answer 8

Coagulase positive = S. aureus

Coagulase negative =

• S. epidermidis (Novobiocin sensitive)
• S. saprophyticus (Novobiocin resistant)

Question 9

Gram Positive Cocci, Catalase negative (chains):

• Optochin sensitive vs. resistant?
• Bacitracin sensitive vs. resistant?

Answer 9

Streptococcus

Optochin - Viridans is Resistant; Pneumoniae is Sensitive
— “OVRPS” (overpass)

Bacitracin - group B strep are Resistant; group A strep are Sensitive
— “B-BRAS”

Question 10

Gram Negative Rods:

- Zoonotic organisms?

Answer 10

• Francisella
• Brucella
• Pasteurella
• Bartonella

Question 11

Gram Negatives:

- Pleomorphic organisms?

Answer 11

• Rickettsiae (Giemsa)

- Chlamydiae (Giemsa)

Question 12

Which bacterial organism does not Gram stain b/c it has no cell wall?

Answer 12

Mycoplasma

cell membrane contains sterols

Question 13

Which bacterial organism has Mycolic Acid & a high Lipid content in their cell wall?

Answer 13

Mycobacteria

Question 14

Bugs picked up by Giemsa stain?

Answer 14

Chlamydia, Borrelia, Rickettsiae, Trypanosomes, Plasmodium

Certain Bugs Really Try my Patience

Question 15

Bugs picked up by the Ziehl-Neelson (carbol fuchsin) stain?

Answer 15

Nocardia & Mycobacterium

acid fast organisms

Question 16

Bugs picked up by the India Ink stain?

Answer 16

Cryptococcus neoformans

Mucicarmine can also be used to stain thick polysaccharide capsule red

Question 17

Bugs picked up by Silver stain?

Answer 17

Legionella, Helicobacter pylori, & Fungi (e.g. Pneumocystis)

Question 18

Obligate aerobes?

Answer 18

Nocardia, Pseudomonas aeruginosa, Mycobacterium tuberculosis, Bacillus

“Nagging Pests Must Breathe”

Question 19

Obligate anaerobes?

Answer 19

Clostridium, Bacterioides, Actinomyces

“anaerobes Can’t Breathe Air”

(lack catalase &/or superoxide dismutuase, thus are susceptible to oxidative damage)

Question 20

Obligate intracellular organisms?

Answer 20

Rickettsia & Chlamydia

“stay inside b/c it’s Really Cold”
can’t make own ATP

Question 21

Facultative intracellular organisms?

Answer 21

Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, Yersinia pestis

“Some Nasty Bugs May Live FacultativeLY”

Question 22

Catalase-positive organisms?

Answer 22

Pseudomonas, Listeria, Aspergillus, Candida, E. coli, S. aureus, Serratia

“you need PLACESS for your CATs”

• recurrently infect ppl w/ chronic granulomatous disease (NADPH oxidase deficiency) b/c they degrade the limited H2O2

Question 23

H. influenza - Culture/media reqs?

Answer 23

Chocolate agar w/ Factors V (NAD+) & X (hematin)

Question 24

N. gonorrhoeae & meningitidis - Culture/media reqs?

Answer 24

Thayer Martin (VPN) Media:

• Vancomycin (inhibits gram +’s)
• Polymyxin (inhibits gram -‘s except Neisseria)
• Nystatin (inhibits fungi)

“to connect to Neisseria, use your VPN client”

Question 25

B. pertussis - Culture/media reqs?

Answer 25

Bordet-Gengou (potato) agar

Question 26

C. diphtheriae - Culture/media reqs?

Answer 26

Tellurite plate, Loffler’s media

Question 27

M. tuberculosis - Culture/media reqs?

Answer 27

Lowenstein-Jensen agar

Question 28

M. pneumoniae - Culture/media reqs?

Answer 28

Eaton’s agar

Question 29

Lactose-fermenting enterics - Culture/media reqs?

Answer 29

Pink colonies on MacConkey’s agar
(fermentation produces acid, turning colony pink)

E. coli is also grown on eosin-methylene blue (EMB) agar as colonies w/ green metallic sheen

Question 30

Legionella - Culture/media reqs?

Answer 30

Charcoal yeast extract agar buffered w/ cysteine & iron

Question 31

Fungi - Culture/media reqs?

Answer 31

Sabourad’s agar

“Sab’s a FUN GUY”

Question 32

Encapsulated bacteria?

They have a positive ______ reaction.

Answer 32

Streptococcus pneumoniae, Haemophilus influenzae type B, Neisseria meningitidis, E. coli, Salmonella, Klebsiella pneumoniae, Group B Strep

• Positive Quellung Reaction (capsule swells)
• Are opsonized, then cleared by spleen

Question 33

Asplenics have decreased opsonizing ability & are at risk for severe infections (esp. of encapsulated bugs).
What vaccines should be given?

Answer 33

S. pneumoniae, H. influenzae, N. meningitidis

Question 34

Urease-positive bugs?

Answer 34

Cryptococcus, H. pylori, Proteus, Ureaplasma, Nocardia, Klebsiella, S. epidermidis, S. saprophyticus

“CHuck norris hates PUNKSS”

Question 35

4 pigment-producing bacteria?

Answer 35

Actinomyces isralii - yellow “sulfur” granules composed of filaments of bacteria
(Israel has yellow sand)

S. aureus - yellow pigment
(aureus = Latin for gold)

Pseudomonas aeruginosa - blue-green pigment
(Aerugula is green)

Serratia marcescens - red pigment
(think, red maraschino cherries)

Question 36

Name causative organism.

Single broad-based bud seen on KOH prep from a pulmonary infiltrate

Answer 36

Blastomyces dermatitidis

Question 37

Gram positive organisms?

Answer 37

Cocci = Staph & Strep

Branching Filamentous = Actinomyces & Nocardia

Rods = Corynebacterium, Bacillus, Listeria, Clostridium, Mycobacterium

“Corny Actors Knock Back Listerine in the Closet” (+ Staph, Strep, & Mycobacterium)

Question 38

Gram Negative Rods:
Respiratory Organisms (aerosol transmission)?

Answer 38

• Haemophilus (pleomorphic)
• Legionella (silver)
• Bordetella