Written Review

Production of beta lactamase is inducible in which organisms

haemophilus influenza and staph aureus

Which of the following is NOT consistent with strep pneumoniae

Catalase Negative

Bile solubility +

Bile esculin hydrolysis +

Alpha hemolysis on sheep blood agar

Bile esculin hydrolysis +

What test can differentiate Viridans strep from group D strep and enterococcus

Bile esculin

Optimal temp for Yersinia

25C

PYR: colorimetric method to ID _____and _____

enterococci and Group A strep

Bacitracin: used to ID ________ and differentiate from other beta-hemolytic streptococci

group A beta-hemolytic strep (S)

Optochin: Used to ID __________

Streptococcus pneumoniae (S)

Novobiocin: Used to ID _____from other coag neg staph

S. saprophyticus (R)

Cefinase: Used to isolate beta-lactamase producing colonies of:

1. Staph

2. Haemophilus

3. Enterococci

4. Anaerobes

5. Neisseria gonorrhoea

LAP: Used to ID___________. Specifically_______ from _______, ______

catalase negative gram positive cocci

Aerococcus from Streptococcus, Enterococcus (+)

MCAT (butyrate esterase): Used to ID______

Moraxella catarrhalis (+)

AST for coliforms should routinely include which antibiotic?

Gentamicin

Know what IMVC tests look like

How to perform Nitrate test?

Detect nitrate reductase (NO3 reduction)

Procedure:

How to perform Sodium Hippurate?

Detects hippuricase (hippurate—> glycine and benzoic acid)

Procedure:

How to perform VP?

Detects acetyl methyl carbonyl production (from glucose fermentations)

Procedure: Add reagent A and B after incubation and observe for color change

How to perform MR?

Detects acid production (pH<4.5) during glucose fermentation

Procedure: add methyl red indicator at the end of incubation

IMVIC is used to ID organisms in the _______group

coliform (GNR, aerobic/facultative anaerobic, and produces gas from lactose within 48 hrs)

What 4 things are needed to classify Enterobacteriaceae?

1. Nitrate reducer

2. Motile (except Shigella, Kleb, and sometimes Yersinia)

3. Oxidase (-)

4. Glucose Fermentor

Agents of Bioterrorism

Y. pestis

Route: Fleas

Agents of Bioterrorism

B. Anthraces

Route: Farm Animals (woolsorters!)

Agents of Bioterrorism
B. Anthraces can present as:

• _____(most common)

• _____

• _____

• cutaneous (most common)

• pulmonary

• gastrointestinal

Agents of Bioterrorism

F. tularensis “rabbit fever”

Agents of Bioterrorism

Brucella

Route: contaminated animal products

Agents of Bioterrorism

Brucella can cause _____fever

undulant

Agents of Bioterrorism

B. Pseudomallei

Route: contaminated water and soil

List the 4 main organisms under Food Bioterrorism

1. Salmonella

2. Shigella

3. E.coli O157

4. Vibrio

Strep Chart (in reference book-only common ones)

What organisms can satellite around other colonies on SBA?

Haemophilus sp. and anything fastidious

Can MALDI be used to ID Shigella?

NO; use Vitek

What are the screening disks and diameters for ESBL?

CAZ <22mm

CRO <25mm

What is the follow up fo ran ESBL screen?

(CAZ/CLA) - CAZ

(CRO/CLA) - CRO

5mm difference of either = (+)

What organisms get an ESBL screen?

1. E.coli

2. Kleb

3. Proteus mirabilis

How is the KB zone size determined?

CLSI

Minimum Inhibitory Concentration

conc. that prevents organism from growing

Minimum Bactericidal Concentration

conc. that completely kills organism

List 4 Beta lactamase antibiotics

1. Penicillins

2. Cephalosporins

3. Carbapenems

4. Monobactams

Colony counts using a calibrated loop of 1 uL:

0-10=

10-99=

100+=

0-10= 10³

10-99= 10⁴

100+ = 10⁵

Colony counts using a calibrated loop of 10uL:

0-10=

10-99=

100+=

0-10= 10²

10-99= 10³

100+= 10⁴

What causes a D zone?

Inducible penicillin resistance between Clindamycin and Erythromycin

How to test for penicillin on S. viridans?

E test or 1ug OX disc

How to test for penicillin on Strep pneumo?

E test or 1ug OX disc on MH w/ 5% blood

Orgs found in blood cultures that are associated with colon cancer

• Clostridium necrophorum

• Streptococcus bovis

What is the common cause of sepsis in neonates and how do we test for it?

Group B strep ( Strep agalactiae)

Testing: Carrot broth, Detect agar, lance field antigen test

What are the primary & secondary diseases caused by Group A strep?

Primary (during infection):

1. Scarlet Fever

Secondary (after infection):

1. Rheumatic Fever

2. Post-Streptococcal glomerulonephritis

Erysipelothrix rhusiopathiae

Source: piggy’s and common in occupational exposure handling animal products

Characteristics:

Gram (+) : rods in chains or V shape

Catalase (-)

H2S (+)

Non motile

Resistant to VANCO

What internal ailment can Enterotoxin by staph aureus cause?

Food poisoning

What external ailment can Enterotoxin by staph aureus cause?

Scalded Skin Syndrome (Ritter’s Disease)

Incubation requirements for Pertussis

Temp: 35-37C

Media: Bordet-gengou or Regan-Lower

Incubation requirements for Legionella

Temp: 35C

Media: BCYE

What is permease deficiency and ONPG used for?

determine the ability of an organism to produce β-galactoside enzyme

• used on enterobacteriaciae

What causes Gastric ulcers and how is it identified?

H. pylori

Testing: Tissue biopsy and Urea breath test

Bacillus ____decolorizes easily

over

Bacillus can be ____hemolytic

beta

What can cause a pseudomembrane in the throat?

Corynebacterium diphtheria

What media is used for C. diphtheria and how does it appear?

Media: Tellurite media

Appearance: mercury droplets

What is in a TSI?

Slant: Lactose and Sucrose

Butt: Glucose

Indicator: Phenol Red (Yellow = acid; Red = alkaline)

What are all the possible TSI reactions?

(Glucose: Lactose: Sucrose—> 1: 10: 10)

Know TSI for Enterobacteriaceae

Mycoplasma isolates have been associated with_____, _____, and _____

endocarditis, sternal wound infections, and arthritis

M. pneumoniae may cause____, ____or _____

bronchitis, pharyngitis, or primary atypical pneumonia

M. pneumoniae has historically been diagnosed by ____methods

serological

Due to their lack of cell wall Mycoplasma are inherently resistant to ____

β-lactams

TCBS Agar and vibrio organisms

yellow=sucrose utilization

OFPBL Agar is used to select for ______especially in ____patients

Burkholderia cepacia; CF

How does OFPBL Agar inhibit other organisms?

selective agents polymyxin B and bacitracin

Standard MH Requirements

pH: 7.2-7.4

Specific cation conc.

Depth: 4mm

Temp: 35C

Incolum: 0.5 McFarland with fresh colonies (16-24 hrs)

AST can be read at 16-18 hours except for ____and ______

Staph and Enterococcus ( must be 24 hours)

Top 3 clinically sig Non Fermenters

1. Psued

2. Acinetobacter

3. Stenotrophomonas maltophilia

Non Fermenters

Pseudomonas

GNC

NLF

OX (+)

TSI: K/K

Grapes

motile

Non Fermenters

Acinetobacter baumanii

GNC

NLF

OX-

OF glucose: yellow/green

non motile

Non Fermenters

Stenotrophomonas

GNC

NLF

OX-

OF glucose: green/green

Alk Phos +

motile

Spirochetes

Borrelia

Disease:

Source:

Disease: Lyme disease

Source: Hard ticks

Spirochetes

Leptospira

Disease:

Source:

Disease: Leptospirosis

Source: urine of animals (Hawaii 70% of infections )

Spirochetes

Treponemes pallidum

Disease:

Source:

Disease: Syphilis !!

Source: Sexual Contact

What is the MCAT disc used for?

Detects butyrate esterase to ID Moraxella catarrhalis

Tests for Syphilis

VDRL -screen

RPR - rapid

What is Pseudomonas intrinsically resistant to?

SXT

What is Kleb intrinsically resistant to?

ampicillin

MTM ingredients

SXT (trimethoprim)

Colliston

Vancomycin

Nystatin

“molar tooth”

Actinomyces

What does this suggest in males? females?

males: Neisseria gonorrhoeae

females: can’t say; females have GNC so must culture

culture looked like “bread crumbs”

Fusobacterium nucleatum

What bacteria genera are PAD (phenylalanine deaminase) positive

Proteus

Morganella

Providencia

If strep pneumo is suspected, what is a quick test that can be performed?

bile solubility (+)

IMVC for important organisms

Neisseria carb ferm test

“ chinese/oriental letters” or palisades

Corynebacterium species

What org is incubated in microaerophilic conditions at 42C?

Campy

What orgs require CO2 incubarion

• Neisseria

• Haemophilus

• Strep pneumo

• Capnocytophaga

Can specimens for micro be transported on ice?

No, everything is at RT

What does a Q-score of 0 indicate?

lots of epi’s so poor quality and most likely contamination

What does a Q-score of 3 indicate?

high quality and abundant neutrophils, indicating infection

What organisms are resistant to

• Ampicillin

• Cefazolin

• Augmentin

• Enterobacter

• Citrobacter

• Hafnia

• Serratia

For which antibiotic should you interpret where there is an 80% reduction of growth?

SXT (Trimethoprim-Sulfamethoxazole)

What is used to quench excess stain in Truants stain ( for acid fast bacteria)?

potassium pergmanganate

What is the only non fermenter that is h2s pos

shewanella putrefaciens

What drug is used to rule out MRSA?

FOX (R)

• only OX and CZ reported as (R)

On blood agar, which organism requires

X and V:

only V:

X and V: Haemophilus influenzae

only V: Para influenzae

CVA agar

organism:

Temp:

organism: campy

Temp: 42C; microaero