Module 5 Level 2 Quiz

In the process of ________, microbes detect the presence and density of other microbes and modify their metabolic activity in response.

quorum sensing

Silvadene, a topical treatment for burns, contains 1% silver. What category of antiseptic agent is in Silvadene?

heavy metals

A chemical agent that dissolves lipids can damage

enveloped virions

You are looking at a container of antimicrobial cleaner that contains the active ingredient Benzalkonium Chloride, a cationic surfactant. This cleaner disinfects by: Solar Disinfection is a method to sanitize water using:

Breaking down plasma membrane

Purell is an alcohol-containing antiseptic. Which of the following pathogens would alcohol not be effect against?

Naked virions

The process of filtration is a(n)

sterilizing method

Why are endospores used to measure the effectiveness of autoclave sterilization?

They are very hard to kill

Filtration to disinfect water and prevent infections requires purpose-built filters.

FALSE; sterilize water

A bacterium was isolated from the depths of the ocean.. Which of the following would be the best description of the bacteria?


You have a patient in the acute phase of an infectious disease. You would hypothesize that the pathogens in their body are in the ________ growth phase.


The slope of a linear line on a graph with a logarithmic scale organism indicates the doubling time of the organism.


A microorganism found living under conditions of high ________ is a halophile.

salt concentrations

A microbiologist inoculates a flask of broth to a concentration of 100 bacterial cells per ml. The generation time of the species is 1 hour, and there is no lag phase. How long will it be before the culture contains more than 6,000 cells per ml?

6 Hours

The shortest doubling time is when microorganisms are in the ________ phase.

Log (short doubling time=most growth)

If an antimicrobial compound destroys endospores, it can be assumed that t will also kill gram-negative bacteria.


You expose a bacterial population to an antimicrobial. Which of the following conditions would have no effect on the DRT?

Decreasing population

You are treating a surface with a disinfectant. You know that the DRT of this disinfectant is 30 seconds. You estimate that the level of pathogen contamination on the surface is 1000000 cells. Based on this information how long would it take to kill all t


Difference between sterilization and sanitation

Sterilization is the removal of all microorganisms on an object/surface. Sanitization is just the reduction of pathogens on a surface/ object.

Difference between degerming and sanitization

Degerming is the physical removal of microorganisms form an object. It does not involve inactivating/ killing the microorganisms. Sanitization is when microorganisms are killed/ inactivated.

Difference between antiseptics & disinfectants

Antiseptics kill pathogens on tissues, while disinfectants kill pathogens on an inanimate object.

Difference between low level germicides, intermediate level germicides, and high level germicides

Low level germicides destroy bacteria and some viruses, but do not kill mycobacterium and endospores.
Intermediate-level germicides kill all bacteria (including mycobacterium) but do not effect endospores.
High-level germicides kill all bacteria including

What physical methods of microbial control can sterilize?

Autoclaving, ionizing radiation, filtration, incineration

Alcohol is the most common antiseptic that you will use on a daily basis in an acute care setting. What is its method of action. What pathogens is this antiseptic ineffective against.

Method of action: targets lipids and inactivates membranes, and is ineffective against naked virions endospores

If you wash your hands and apply an alcohol-based antiseptic before drying them will it continue to be effective, why or why not?

No, the water will dilute the alcohol. As alcohol stops being effective at around 50% you run the risk of diluting below it's effective concentration.

What rare pathogen is most resistant to destruction? What method exists to inactivate them?

Prions, and they can be inactivated by enzymes

What are the 4 stages of the microbial growth curve. Please describe what is occurring at each phase with regard to microbial growth and death.

Lag: Bacteria are not replicating but are metabolically active.
Log: Bacteria are replicating at a rate faster than they are dying. The population is increasing at an exponential rate.
Stationary: Bacteria are replicating and dying at equal rates as a key

Why does antibiotic use increase risk for a C. diff infection?

Etiological Agent: Clostridium Dificiile. Causes damage to the GI system, which can lead to mega colon and pseudomembranous colitis. It releases toxins that damage the enterocytes of the GI. It is typically transmitted by direct contact. Antibiotic risk i

What is a biofilm?

A biofilm is a collection of microorganisms that exist in a synergistic relationship. Cells use quorum sensing to allow them to determine their density. Cells release quorum signals as they live. At low densities these signals are quickly diluted by the s

Where is the greatest number of bacteria dying on a microbial death curve?

at the top

What would happen to DRT if The curve if the initial bacterial population was reduced 100-fold.

no change

What would happen to DRT if the curve if an antimicrobial agent was administered at 0�C rather than room temperature.

increase (slope would get less steep) (lower temp decreases effectiveness)