The ciliated epithelial cells in our upper and lower respiratory tract are part of the first line of defense against pathogens. Their function is to

trap and sweep microbes from the bronchi back up to the throat to be swallowed

Enterotoxin, hemolysin, hyaluronidase, coagulase, and streptokinase are all

exotoxins

Capsules are particularly important for

protecting bacteria from host defense mechanisms

Which of the following organisms cause(s) nosocomial infections?

Staphylococcus aureus
E. coli
Pseudomonas aeruginosa

A very virulent bacterial pathogen landed on your arm. Which of the following does the bacteria excrete to get past the skin barrier?

Hyaluronidase

The tetanus toxin is a particularly severe AB-toxin because it has the potential to affect processes that are needed everywhere in the body. It affects the

neurological control of all our muscles, including the heart.

Urinary tract infections are among the most common nosocomial infections, and are mainly associated with the application of

catheters

You are studying two different bacterial isolates. Bacterium A has an LD50 of 5 x 104 while bacterium B has an LD50 of 5 x 107. Which isolate is more virulent?

A

Hemolysin is a toxin that lyses

red blood cells

A _______ can be used on surfaces to sanitize, and a ________ can be used on living tissues to sanitize

disinfectant, antiseptic

_________ are the most difficult to kill

bacterial endospores

Which of these diseases that claim millions of lives per year is caused by a bacterium?

tuberculosis

Peptidoglycan is the main structure of Gram negative bacteria that is recognized by immune cells and that can induce a very strong inflammatory reaction

false

You made a 10% bleach solution on Friday. You can still use it Monday to effectively disinfect your lab bench

false

E. coli is a beneficial member of the gut microbiota, an intracellular gastric pathogen, and an extracellular pathogen of both the gastrointestinal and urinary tract. How can so many strains of E. coli exist with so many different features?

The strains differ in what genes they have and can exchange these genes between each other to give virulence features to other E. coli

After getting stitches in your hand at a hospital, you developed a MRSA infection in the stitches. This would be classified as a nosocomial infection

true

Virulence factors are structures or excretions of bacteria that allow them to infect a host. Every pathogenic bacterium has typically only one virulence factor in its genome

false

_________ are anaerobic bacteria that most often live in the free environment but can cause devastating human diseases, such as tetanus, botulism, and gangrene

Clostridium

_________ is a form of horizontal gene transfer in Bacteria that is facilitated by viruses

transduction

The prevalence of antibiotics in hospital settings can make nosocomial infections more difficult to treat

true

The LPS layer is the

outer membrane in gram negative

Your friend used a towel that was last used by someone infected with Staphylococcus aureus and gets an infection from the towel. What best describes this transmission mode?

fomite

Which of the following diseases can be treated with antibiotics?

strep

One the main sources for nosocomial infectious agents is the people handling the patients

true

“Botox” is short for botulinum toxin and is produced by Clostridium botulinum

true

All viruses require a live host cell to replicate

true

What material is the capsid of a virus particle made of?

protien

What is one major difference between non-enveloped and enveloped viruses?

Enveloped viruses have a lipoprotein membrane surrounding the nucleocapsid, while non-enveloped viruses are “naked”

A virus’ envelope typically consists of

host cell membrane

Why do RNA viruses have a higher mutation rate than DNA viruses?

The viral enzyme RNA replicase lacks proofreading capabilities and therefore is inaccurate

The viral enzyme reverse transcriptase is needed to make

DNA from RNA template

What technique can be used to quantify viruses?

plaque assays

Bacteria are mainly infected by _____ viruses, while Eukarya are more frequently infected by _____ viruses

double strand DNA

single strand RNA

On earth, viruses outnumber bacteria cells

true

Which of the following statements about the presence and distribution of viruses on/in a healthy human is true?

Most viruses are bacteriophages and occur in the large intestine

Bacteriophages infect bacterial hosts in a series of steps, of which the correct order is

attachment, penetration, synthesis, assembly, release

Bacteriophages that exhibit a lytic lifestyle are _______, while lysogenic
bacteriophages are ________.

actively replicating, incorporated into host genome

What is the mode of spreading for the common cold virus?

droplet

formite

direct contact

Everyone who carries herpesvirus always expresses symptoms.

false

People infected with HIV/AIDS typically die from secondary infections
and diseases, and not directly from HIV

true

Why do sexually transmitted diseases tend to go untreated or undetected?

Many sexually transmitted diseases have mild or no symptoms in healthy
individuals.
Many people are shy or reluctant to seek help.
Some sexually transmitted diseases can be mistaken for other diseases

When rabies symptoms set in, death is inevitable

true

Rabies is one of the few diseases where a vaccine is routinely administered post-exposure (after the bite has already happened)

true

Coronaviruses circulate in animals such as bats. They typically reach humans via a _______ infection through an intermediate host such as cat-like animals

spillover

"Botox" is a biotoxin that is cosmetically used - it is injected into the skin to purposely stop muscle control and hence decrease the formation of wrinkles. Which of the toxins we covered today is "botox"?

botulinum toxin, made by Clostridium botulinum