Chapter 4 - Control of Microorganisms - Review Questions

The chemical or physical method that destroys all forms of life is called

a. sterilization

b. disinfection

c. bacteriostatic

d. bactericidal

a. sterilization

Organisms that are the most resistant to heat, chemicals, and radiation are

a. parasites

b. prions

c. bacteria

d. viruses

b. prions

All the following factors play a significant role in the selection and implementation of the appropriate method of disinfection, except

a. temperature

b. contact time

c. biofilms

d. humidity

c. biofilms

If this is present on a surface to be disinfected, it can shield microorganisms from the disinfectant or inactivate the disinfectant. What is this substance?

a. bleach (sodium hypochlortie)

b. organic material

c. hydrochloric acid

d. water

b. organic material

Disinfectants are usually used at this temperature

a. 50-100 C

b. 0-10 C

c. 25-50 C

d. 20-22 C

d. 20-22 C

Chemosterilizers exert their killing effect through all the following mechanisms, except

a. denaturation of cellular proteins

b. damage of RNA and DNA

c. inactivating enzyme subsrates

d. reactions with components of the cytoplasmic membrane

c. inactivating enzyme substrates

Alcohols use this mechanism to inactivate microorganisms

a. denature proteins

b. destroy DNA

c. denature RNA

d. inhibit cell wall synthesis

a. denature proteins

The tech needs to sterilize a piece of equipment that cannot be autoclaved or gas sterilized because the equipment contains lenses, metal, and rubber components. What solution should be used to sterilize this piece of equipment?

a. 10% bleach

b. 37% formalin

c. glutaraldehyde

d. 90% alcohol

c. glutaraldehyde

For the most effective microbial killing, all iodophors must be properly diluted because

a. they stain the skin if too concentrated

b. this decreases contact time for adequate killing

c. there must be enough free iodine to kill the microorganisms

d. this increases the contact time for adequate killing

c. there must be enough free iodine to kill the microorganisms

Even though hypochlorites are inexpensive and have a broad range of microbes that they kill, they are not used as sterilants because of

a. the corrosive nature of the compound

b. the activation required by organic matter

c. short exposure time for sporicidal action

d. long exposure time for sporicidal action

d. long exposure time for sporicidal action.

Many materials in hospitals that must be sterilized cannot withstand steam sterilization. Gas sterilization is used instead, using this gas

a. nitrous oxide

b. oxygen

c. ethylene oxide

d. carbon dioxide

c. ethylene oxide

High-level disinfectants are active against all the following, except

a. parasites

d. spores

c. fungi

d. tubercle bacilli

b. spores

These two alcohols are effective in killing enveloped viruses such as hepatitis B virus (HBV)

a. 50% isopropyl and 50% butanol

b. 95% propanol and 70% ethanol

c. 70% isopropyl and 95% ethanol

d. 70% pentanol and 70% isopropyl

b. 95% propanol and 70% ethanol

The purpose of surgical hand scrubs and waterless hand rubs is to

a. eliminate the transient flora and most of the resident flora on the skin

b. remove all physical dirt and some residential flora

c. remove all resident flora

d. remove all transient flora

a. eliminate the transient flora and most of the resident flora on the skin

Why is laboratory-acquired infection an obvious hazard for personnel working in a microbiology laboratory

a. microbiology personnel do not always adhere to safety practices

b. safety practices are not applicable for the microbiology laboratory

c. in-service education is not provided for microbiology staff

d. personnel deal with a variety of infectious agents: viral, fungal, parasitic, and bacterial

d. personnel deal with a variety of infectious agents including viral, fungal, parasitic, and bacterial.

All of the following organisms can typically cause infection from aerosolization of specimens, except

a. Mycobacterium tuberculosis

b. Brucella spp.

c. Staphylococcus aureus

d. Francisella tularensis

c. Staphylococcus aureus