Make your micro list and check it twice...gonna find out who's naughty & nice! :)

Micro is heavily tested on THE test. Knowing how to differentiate bugs and their virulence factors, how they cause disease and their presentations is critical to scoring well on Step 1. This little list is courtesy of a classmate of mine, Kallie. She used to come up with some of the best ways to re-organize material into concise, manageable bites. Thanks Kallie!

I used this list as I prepared by taking it with me on walks at night and focusing on a few of them, making notes to the side and really getting to know micro. I probably answered 15 questions based just on the info here. It enabled me to narrow down and zero in.

Some Classification Lists

Mimics Appendicitis
Yersinia entericolytica
Salmonella typhi

Cause Fever (same as those that invade host tissues)
EIEC
Shigella
Salmonella enteridis (1/2 the time)
Salmonella typhi
Yersinia
Campylobacter jejuni
Listeria

Survive at Cold Temperatures
Yersinia
Listeria monocytogenes (4C!)

Survive at Hot Temperatures
Campylobacter (42C)

Invade Intestinal Epithelium
Shigella
EIEC
Salmonella enteritidis
Listeria

Invade Lymph Nodes, Bloodstream (systemic sx)
Salmonella typhi
Yersinia
Campylobacter jejuni

Bloody Diarrhea (the invaders!)
Salmonella typhi
Yersinia
Campylobacter
EHEC (does not invade, uses Shiga toxin)
EIEC
Shigella

Gram Positive
--- 6 cause disease
Cocci
Streptococcus
Staphylococcus


Rods
Spore-forming
Bacillus
Clostridium

No Spores
Corynebacterium
Listeria (make endotoxin)

Facultative Intracellular Organisms
Listeria monocytogenes
Salmonella typhi
Yersinia

Non-mobile
Shigella

Only G+ w/ Endotoxin
Listeria monocytogenes

Human = Only Host
Salmonella typhi
Shigella

Bactericidal Antibiotics
penicillins
fluoroquinolones
vancomycin
metronidazole
aminoglycosides (can be both –cidal, -static)

Bacteriostatic Antibiotics
tetracycline
sulphonamides
trimethoprim
chloramphenicol
macrolides
lincosamides
aminoglycosides (both)

Facultative Anaerobes
Staphylococcus (G+)
Listeria (G+)
most G- rods
Mycoplasma

Microaerophilic Bacteria
Streptococcus (G+)
Spirochetes (G-)
Campylobacter (G-)

Obligate Anaerobes
Clostridium (G+)
Bacteroides (G-)

Lactose Fermenting
E. coli

Non-Lactose Fermenting
Shigella
Salmonella typhi
Yersinia
V. cholera

Produces H2S
Salmonella typhi

Sterols in Cell Membrane
Mycoplasma

Not a Normal Part of Flora
Shigella
Salmonella

No Cell Wall
Mycoplasma

Stain Acid-Fast
Mycobacteria

Visualize via Darkfield Micro
Spirochetes

Shiga Toxin (AB)
Shigella
EHEC
EIEC
LT
ETEC
V. cholera (cholera toxin)
Campylobacter jejuni

ST
ETEC
EAEC
Yersinia

Resistance Encoded by Plasmid (modify antibiotic, efflux pump?)
Vancomycin (D-ala-D-ala  D-ala-D-lactose)
Aminoglycosides (modify drug)
Tetracycline (efflux)
Macrolides, Erythromycin (methylation of rRNA)
Sulfonamides (altered permeability)

Resistance Encoded by Chromosome (altered target, altered permeability?)
Quinolones (altered DNA gyrase, topo IV)
Sulfonamides (altered dihydropterate synthase)

AB Toxin
Shiga
E. coli (LT toxin)
V. cholera

TTSS
EHEC
Salmonella
Shigella
Yersinia

HUS
EHEC
Shigella dystenteriae

Invade M Cells
Yersinia
Shigella
Listeria