Med Micro Exam 2

What does neonate mean?

Newborn baby

What is sepsis?

Infection throughout the body

What food source is commonly linked to Listeria?

Unpasteurized dairy and other contaminated foods

How can Listeria be distinguished from Corynebacterium by shape?

Listeria is more uniform in shape

What gives acid-fast bacteria survival and resistance to decolorization?

Mycolic acids in the cell wall

What is a limitation of the PPD test?

It cannot distinguish active disease from latent infection or prior BCG vaccination

What is the most useful first imaging test when TB is suspected?

Chest X-ray

In meningitis, what does gram-negative diplococci suggest?

Neisseria meningitidis

Which Neisseria grows on chocolate agar and which grows on blood agar?

N. gonorrhoeae grows on chocolate agar; N. meningitidis grows on blood agar

How does N. gonorrhoeae avoid immune detection?

Antigenic variation of pili and Opa proteins

Why can drug-resistant gonorrhea spread easily?

It may go undetected and be transmitted without the person knowing

What can untreated gonorrhea in females lead to?

Pelvic inflammatory disease

How does Streptococcus pneumoniae appear on Gram stain?

Gram-positive, lancet-shaped diplococci

Where are meningococcal outbreaks more likely to occur?

Close quarters such as dorms, prisons, and barracks

What does Haemophilus influenzae require for growth?

Hemin and NAD

Why are capsules dangerous virulence factors?

They are antiphagocytic and help bacteria evade the immune system

What organism classically causes swollen epiglottis, and what should be avoided?

Haemophilus influenzae type b; do not swab the throat

What key lab feature distinguishes Enterobacteriaceae from many other gram-negative rods?

They are oxidase negative

What does a metallic green sheen in E. coli indicate?

Lactose fermentation

What type of diarrhea does ETEC cause, and where?

Traveler’s diarrhea in the small intestine

What type of diarrhea does STEC cause, and where?

Bloody diarrhea in the large intestine

Why are UTIs more common in women?

The urethra is shorter

Why can Salmonella more easily become systemic?

It can survive in macrophages

Where can Salmonella be harbored chronically?

The gallbladder

How many Shigella organisms can cause disease?

About 100 to 200 organisms

How does Shiga toxin cause disease?

It blocks protein synthesis

What food is Vibrio classically linked to?

Raw oysters

What is the basic morphology of Vibrio?

Curved gram-negative rod

What pigment-related factor is produced by Pseudomonas aeruginosa?

Pyocyanin

What are two classic identifiers of Pseudomonas aeruginosa?

Green pigment and a grape-like odor

What autoimmune condition is associated with Campylobacter infection?

Guillain-Barré syndrome

What growth conditions does Campylobacter require?

Low oxygen and high temperature

How does H. pylori survive in the stomach?

Urease helps neutralize acid

How does H. pylori damage the stomach lining?

It destroys the mucus barrier