Chapter 04: Control of Microorganisms

Mahon: Textbook of Diagnostic Microbiology, 6th Edition

MULTIPLE CHOICE

1. The chemical or physical method that destroys all forms of life is called
a. sterilization.
b. disinfection.
c. bacteriostatic.
d. bactericidal.
ANS: A
Sterilization is the destruction of all forms of life, including bacterial spores. Disinfection is a
process that eliminates a defined scope of microorganisms, including in some cases spores.
Bacteriostatic inhibits the growth of microorganisms. Bactericidal kills bacteria.

OBJ: Level 1: Recall

2. Organisms that are the most resistant to heat, chemicals, and radiation are
a. parasites.
b. prions.
c. bacteria.
d. viruses.
ANS: B
Prions are naked pieces of protein, so they are harder to kill than any other organism. Viruses
usually contain a nucleic acid, and all the mentioned forms of killing can effectively disrupt
their nucleic acid. Bacteria and parasites are complete organisms that are killed by disinfection
and sterilization, even in the spore and cyst stages.

OBJ: Level 1: Recall

3. After using the phone, the laboratory tech sprayed the receiver with a chemical spray. This
process will kill a defined scope of microorganisms. What is this process called?
a. Sterilization
b. Bacteriostatic
c. Disinfection
d. Bactericidal
ANS: C
Disinfection kills a defined scope of microorganisms. Sterilization kills all organisms and
spores at a site. Bacteriostatic and bactericidal are adjectives that describe the particular action
of chemical agents: to inhibit bacterial growth or kill bacteria.

OBJ: Level 2: Interpretation

4. Before performing a phlebotomy, the phlebotomist will clean the area on a patient’s arm with
a substance before inserting the needle. This substance is called a(n)
a. disinfectant.
b. sterilizer.
 c. antiseptic.
d. bactericidal.
ANS: C
An antiseptic is a substance applied to the skin for the purpose of eliminating or reducing the
number of bacteria present. A disinfectant is a chemical agent used to kill microorganisms on
an inanimate object. To sterilize is to kill all life; skin will still have organisms growing after
wiping. Bactericidal is the process of killing bacteria.

OBJ: Level 2: Interpretation

5. 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.
ANS: D
Humidity is not important when attempting to disinfect or kill organisms. Temperature,
contact time, and biofilms all play a role in selection and implementation of the appropriate
method of disinfection.

OBJ: Level 1: Recall

6. When eliminating organisms from inanimate objects, higher numbers of organisms require
longer exposure times because
a. all disinfecting agents are not alike and some require shorter times.
b. the chemical composition of the disinfecting agent varies.
c. disinfecting agents containing carbon tetrachloride require longer times to act.
d. it takes longer to eliminate 99% of microorganisms.
ANS: D
When there are higher numbers of microorganisms, it takes longer to kill 99% of the
microorganisms present. Although disinfectants are different, it still takes longer to kill more
organisms. The chemical composition of a disinfecting agent may affect the time required to
kill microorganisms, but microbial load is a determining factor.

OBJ: Level 1: Recall

7. 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 hypochlorite)
b. Organic material
c. Hydrochloric acid
d. Water
ANS: B
Organic matter (e.g., blood, pus) can keep the disinfectant from reaching and killing the
microorganism. Bleach, hydrochloric acid, and water can counteract another disinfectant, but
they cannot shield microorganisms from a disinfectant.
 OBJ: Level 1: Recall

8. Disinfectants are usually used at this temperature.

a. 50° C to 100° C
b. 0° C to 10° C
c. 25° C to 50° C
d. 20° C to 22° C
ANS: D
Disinfectants are usually used at room temperature (20° C to 22° C). Too high or too low a
temperature can actually inactivate a disinfectant.

OBJ: Level 1: Recall

9. Pasteurization achieves _____.

a. disinfection
b. sterilization
c. asepsis
d. filtration
ANS: A
Pasteurization kills food-borne pathogens, but not microbial spores present in a liquid.
Because sterilization is killing of all microorganisms plus spores and cysts, pasteurization
only disinfects. Asepsis describes no bacteria present. Filtration describes another method of
disinfection where microorganisms are removed from a liquid by a physical device—a filter.

OBJ: Level 1: Recall

10. 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 substrates.
d. reactions with components of the cytoplasmic membrane.
ANS: C
Inactivating an enzyme substrate may or may not have an effect on cellular function. If a
chemical can denature proteins that are used by the cell, damage RNA or DNA, or react with
components of the cell membrane, they can damage the cell.

OBJ: Level 1: Recall

11. Alcohols use this mechanism to inactivate microorganisms.

a. Denature proteins
b. Destroy DNA
c. Denature RNA
d. Inhibit cell wall synthesis
ANS: A
Alcohols disrupt the tertiary and quaternary structure of the cell wall proteins to destroy
microorganisms. They do not have the capability to destroy DNA, denature RNA, or inhibit
cell wall synthesis.
 OBJ: Level 1: Recall

12. 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
ANS: C
Glutaraldehyde is the sterilant of choice, because it is not inactivated by organic material, and
it can kill both microbes and spores, depending on contact time. Ten percent bleach cannot be
used because it is a corrosive and can corrode metal; 37% formalin cannot be used because it
is a carcinogen, and the Occupational Safety and Health Administration (OSHA) does not
recommend it for routine sterilizing or disinfecting; 90% alcohol can be corrosive, but it is
also inactivated with any organic material that may be present on the instrument.

OBJ: Level 1: Recall

13. 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 contact time for adequate killing.
ANS: C
The reason for diluting iodophors properly is that the dilution ratio is important to ensure there
is enough free iodine to kill microorganisms. When iodophors are used as skin preparations,
contact time is essential for killing microorganisms. Contact time does not depend on dilution.
Iodophors are considered nonstaining.

OBJ: Level 1: Recall

14. 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.
ANS: D
Hypochlorites require a long exposure time to kill spores, and they are inactivated by organic
material present on an object. They are not used as a disinfectant because they are corrosive.

OBJ: Level 1: Recall

15. 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
ANS: C
Ethylene oxide is usually mixed with nitrogen or carbon dioxide before use because it is
explosive in its pure form. It is used in hospitals and in the manufacturing industry for
sterilizing thermoplastic products. Nitrous oxide, oxygen, and carbon dioxide are all gases,
but they do not kill microbes or their spores.

OBJ: Level 1: Recall

16. Why should health care workers wash their hands after coming into contact with a patient?
a. To reduce the amount of red blood cells transmitted from one patient to the next
b. To reduce the occurrence of hemolytic transfusion reactions
c. To reduce the need for antiseptics and disinfectants
d. To reduce the spread of pathogenic bacteria from one individual to another
ANS: D
Any pathogenic bacteria present on the hands of one individual will be passed on to the next
individual unless the hands are washed to remove the pathogens. Hands visibly contaminated
with red blood cells are always washed after becoming soiled. Hemolytic transfusion reactions
are caused by the intravenous administration of red blood cells. Antiseptics and disinfectants
will always be needed to cleanse skin and inanimate objects to free them of pathogenic
bacteria.

OBJ: Level 1: Recall

17. High-level disinfectants are active against all the following, except
a. parasites.
b. spores.
c. fungi.
d. tubercle bacilli.
ANS: A
High-level disinfectants are active against vegetative cells, tubercle bacilli, spores, fungi, and
viruses. These disinfectants may have no activity against parasite cysts or egg forms.

OBJ: Level 1: Recall

18. This agency regulates the use, sale, and distribution of antimicrobial pesticide products for
certain inanimate, hard, nonporous surfaces, or incorporates into substances under the
pesticide law.
a. Antimicrobial Division of Environmental Protection Agency (EPA)
b. Centers for Disease Control and Prevention (CDC)
c. U.S. Army Medical Research Institute for Infectious Diseases (USAMRIID)
d. U.S. Food and Drug Administration (FDA)
ANS: A
 The Antimicrobial Division of the EPA regulates the use of antimicrobials on inanimate,
nonporous surfaces. The CDC acts as a clearinghouse for information of medically important
bacteria and houses one of two biosafety level 4 (BSL-4) laboratories. The other (BSL-4)
laboratory is found at the Army infectious disease research facility, USAMRIID. The FDA
regulates substances that are put into the body.

OBJ: Level 1: Recall

19. 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
ANS: C
The only two alcohols used in U.S. hospitals that kill HBV are 70% isopropyl and 95%
ethanol.

OBJ: Level 1: Recall

20. This chemical is a saturated 5-carbon dialdehyde that has broad-spectrum activity, rapid
killing action, and remains active in the presence of organic matter.
a. Formalin
b. Formaldehyde
c. Haloaldehyde
d. Glutaraldehyde
ANS: D
Glutaraldehyde is a good killing agent because it has broad-spectrum activity and rapid killing
action, remains active in the presence of organic matter, and can be used on sensitive
equipment. Formalin is designated as a carcinogen by the OSHA, and worker exposure limits
have been set. These adverse effects limit its usefulness. Formaldehyde is a gas that is usually
known as formalin. Haloaldehyde is not used as a disinfectant.

OBJ: Level 2: Interpretation

21. These disinfectants are cationic, surface-activated agents that work by reducing the surface
tension of molecules in a liquid, resulting in the disruption of the cellular membrane of
microbes.
a. Quaternary ammonium compounds
b. Heavy metals
c. Chlorines
d. Iodophors
ANS: A
Quaternary ammonium compounds are disinfectants that are cationic, surface-activated agents
that disrupt the cellular membrane of microbes. Heavy metals are bacteriostatic. The
mechanism, by which chlorines kill microorganisms, is the oxidative effects of hypochlorous
acid. Iodophors kill through the action of periodic acid.

OBJ: Level 1: Recall

22. This organization regulates chemical skin antiseptics.
a. EPA
b. FDA
c. CDC
d. National Institutes of Health (NIH)
ANS: B
The FDA regulates chemical skin antiseptics. The Antimicrobial Division of the EPA regulates
disinfectants. The CDC is the nation’s clearinghouse on infectious diseases. The NIH is a
conglomerate of special federal agencies that award research grants to further knowledge in a
particular area.

OBJ: Level 1: Recall

23. The main goal of handwashing is to

a. sterilize a person’s hand.
b. increase the risk of passing on pathogens.
c. eliminate transient flora.
d. disinfect a person’s hands.
ANS: C
A person’s hands are never sterile; therefore, the best handwashing scenario would be to
cleanse the hands of transient flora. Sterilizing someone’s hands would also strip the hands of
essential oils that would contribute to drying and cracking of the skin. Washing would
eliminate most pathogens, thereby decreasing, not increasing, a person’s ability to transmit
pathogens. Disinfection occurs when microorganisms are killed on inanimate objects.

OBJ: Level 1: Recall

24. Routine handwashing in health care settings mandates washing at all the following times,
except
a. in high-risk areas such as ICU and burn units.
b. on entering protective isolation units.
c. before and after routine patient contact.
d. when gloves become soiled during a procedure or dressing change on the same
patient.
ANS: D
Soiled gloves are changed during a procedure or dressing change on a single patient, but the
hands are not washed until contact with that patient terminates.

OBJ: Level 1: Recall

25. 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.
ANS: A
 Surgical scrubs try to eliminate as much bacteria from the surgeon’s hand as possible. In case
the surgeon’s glove is torn or punctured, very little bacteria will enter the surgical wound.
Transient and resident flora must be removed by the surgical hand scrubs and waterless hand
rubs.

OBJ: Level 1: Recall

26. The most common iodophor used in the United States for preoperative skin preparation is
a. calcium iodophor.
b. 95% ethanol and iodine.
c. tincture of iodine.
d. povidone-iodine.
ANS: D
Povidone-iodine contains a low amount of free molecular iodine, reducing toxic effects,
staining, and irritation. It also provides slow and continuous release of iodine. Tincture of
iodine is not used frequently. Ca iodophor and 95% ethanol and iodine are not used for
preoperative surgical skin preparation.

OBJ: Level 1: Recall

27. This topical antiseptic disrupts the microbial cell membrane and precipitates the cellular
contents.
a. Chlorhexidine gluconate
b. Povidone-iodine
c. 95% ethanol
d. 60% isopropyl alcohol
ANS: A
The bactericidal mechanism for chlorhexidine gluconate is to disrupt the microbial cell
membrane and precipitate the cellular contents. Povidone-iodine uses hypoiodonic acid and
free iodine to disrupt the cell and eventually kill it. The bactericidal mechanism for alcohols is
denaturing proteins.

OBJ: Level 1: Recall

28. This compound is a diphenyl ether and it exerts its bactericidal effects by disrupting the cell
wall. It has good activity against gram-positive cocci, but poor activity against fungi. What is
its name?
a. 95% ethanol
b. Triclosan
c. Chlorhexidine gluconate
d. Povidone-iodine
ANS: B
Triclosan is a diphenyl ether, and it exerts its bactericidal effects by disrupting the cell wall.
Ninety-five percent ethanol denatures the cellular proteins. Chlorhexidine gluconate disrupts
the cellular membrane and spills the cell’s contents. Povidone-iodine kills the bacteria with
free iodine and hypoiodonic acid.

OBJ: Level 2: Interpretation

29. Laboratory safety includes all the following areas, except
a. radioactivity.
b. chemical.
c. isolation.
d. fire.
ANS: C
Isolation safety and precautions are usually practiced in conjunction with the patient on the
floor or outpatient setting. In the laboratory, there are few patients, so safety focuses on areas
like radioactivity, chemical safety, and fire safety.

OBJ: Level 1: Recall

30. 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.
ANS: D
All specimens handled by laboratory techs are considered to be potentially infectious.
Therefore, if a person is careless, a laboratory-acquired infection can occur. Microbiology
personnel should follow safety procedures for their own safety. Safety procedures do apply to
the microbiology laboratory, and training is provided to each employee.

OBJ: Level 1: Recall

31. The comprehensive safety program for the microbiology laboratory needs to fulfill all the
following provision, except:
a. It is specific to the hospital and does not need to conform to state, local, and
federal regulations.
b. It must address biological hazards.
c. It must teach correct techniques for lifting and moving heavy objects and patients
(where applicable).
d. It must describe the safe handling, storage, and disposal of chemicals.
ANS: A
The safety program must comply with federal and state regulations, hospital procedures, and
good laboratory practice. It needs to address all safety hazards (fire, chemical, radiologic, and
biological) and be uniformly applied. Procedures need to be written, and employees need to
take responsibility for keeping their workplace safe.

OBJ: Level 1: Recall

32. Processing of patient specimens and handling of actively growing cultures of microorganisms
put an employee at risk of potential contact with the infectious agent through all the following
routes, except
a. mucous membranes.
b. blood splashed onto intact skin.
 c. inhalation of aerosols.
d. accidental ingestion.
ANS: B
When working with specimens and culture plates, there is little chance of contracting an
infection if blood is splashed onto intact skin. Infection—through the mucous membranes by
rubbing eyes with contaminated hands, from inhaling aerosolized microorganisms, or by
accidental ingestion—is possible when handling specimens and actively growing culture
plates.

OBJ: Level 1: Recall

33. 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.
ANS: C
Cases of S. aureus infection of laboratory workers occur often, but not usually through aerosol
inhalation. Many reported cases of laboratory workers being infected with M. tuberculosis
after being exposed to aerosols when processing sputum specimens fill the literature. Brucella
and F. tularensis are very infectious organisms and several cases a year are reported of
laboratory workers who contract the disease after processing culture specimens.

OBJ: Level 1: Recall

34. What protective measures can a laboratory worker take when working with actively growing
cultures to ensure that they do not become infected?
a. Ensure that fungal cultures are sealed and worked in a biosafety cabinet.
b. Wash their hands at the end of their shift.
c. Handle specimens routinely, using extra care for HIV and HBV cultures.
d. Take off bandages on fingers when reading plates.
ANS: A
Fungal cultures produce many infectious spores that can disseminate rapidly via the
ventilation system if a plate is opened on the bench in a laboratory. These cultures should
always be handled in a biosafety cabinet. Bench technicians should wash their hands
frequently to ensure the number of pathogenic microorganisms on their hands is always low.
All specimens should be handled as though they are HBV and HIV positive—with extreme
care. Cuts on the hand should always be covered by finger cots or gloves.

OBJ: Level 1: Recall

35. The laboratory exposure control plan should contain all the following, except
a. engineer and work practice controls.
b. review of control plan every 5 years.
c. methods of compliance for Standard Precautions.
d. guidelines for handling and disposal of regulated waste.
ANS: B
 The exposure control plan is mandated by the OSHA to protect workers against blood-borne
pathogens. This plan must be reviewed and updated annually. It must contain a determination
of tasks and procedures that may result in an occupational hazard, a plan to investigate all
exposure incidents, and a plan to prevent these from reoccurring, methods of compliance for
Standard Precautions, engineering and work practice controls, personal protective equipment
(PPE), guidelines for ensuring that the work site is maintained in a clean and sanitary manner,
guidelines for handling and disposal of regulated waste, and a training program for all
employees (OSHA Bloodborne Standards).

OBJ: Level 1: Recall

36. Universal/Standard Precautions require that

a. only some body fluids be considered infectious and capable of transmitting
disease.
b. body fluids with visible blood be treated as noninfectious.
c. blood and body fluids from all patients be considered infectious and capable of
transmitting disease.
d. urine and feces be considered noninfectious.
ANS: C
Anything that comes from a patient is capable of transmitting disease. Blood and all body
fluids, including secretions and excretions, except sweat, regardless of whether visible blood
is present, are considered infectious.

OBJ: Level 1: Recall

37. Engineering controls and work practice controls to ensure Standard Precautions are followed
include all the following, except
a. eyewash stations.
b. the use of safety needles.
c. plastic shield barriers.
d. fire blankets.
ANS: D
The OSHA defines engineering controls as controls that isolate or remove the hazard from the
workplace. Some examples of engineering controls are the use of closed tube sampling by
laboratory equipment, the use of safety needles and single-use holders, eyewash stations,
emergency showers, and plastic shield barriers. Ideally laboratories should have negative air
pressure, access to the laboratory should be limited, and there should be a plan to prevent
insect infestation.

OBJ: Level 1: Recall

38. Standard Precautions do not address which of the following?

a. Handwashing
b. Gloves
c. Laboratory coats
d. Respirators
ANS: D
 Respirators are not included in the items addressed by Standard Precautions because they are
used in a biosafety level 3 (BSL-3) laboratory. To ensure the guidelines required in Standard
Precautions are followed within the laboratory, engineering controls and work practice
controls are instituted, and employers must provide PPE.

OBJ: Level 1: Recall

39. Safety program and work practice controls consist of all of the following, except
a. ensuring written procedures are in place for a task.
b. altering the manner in which a task is performed to reduce exposure to infectious
agents.
c. allowing workers to eat at the bench if it gets busy and they do not have time to
take a lunch break.
d. reviewing the procedure manual annually.
ANS: C
Safety programs and work practice controls consist of altering the manner in which a task is
performed to reduce the likelihood of exposure to infectious agents. This is accomplished by
no mouth pipetting; no eating, drinking, or applying cosmetics in the laboratory; disinfecting
workstations at the end of each shift and after any spill of infectious material; no recapping or
breaking of contaminated needles; disposal of needles in an appropriate puncture-resistant
container; performing procedures in a manner to minimize splashing and the generation of air
droplets; placing specimens for transport in well-constructed containers with secure lids to
prevent leakage of infectious materials; and frequent handwashing.

OBJ: Level 1: Recall

40. All of the following are examples of PPE, except

a. gloves.
b. laboratory coats.
c. safety glasses.
d. prescription glasses.
ANS: D
PPE must be protective and appropriate. Blood and body fluids must not be able to penetrate
the PPE material. Prescription glasses are not considered PPE because splashes of blood and
body fluids can get to the eye by coming in around the sides, top, and bottom of the glasses.
Safety glasses form a barrier where body fluids cannot come in around the sides, top, or
bottom.

OBJ: Level 1: Recall

41. Technicians are doing the morning chemistry run. Once they load the specimens onto the
instrument, they remove their gloves to do paperwork in a clean area of the laboratory. What
should the technicians do after removing their gloves?
a. Reposition the tubes in the racks.
b. Take a break and eat a snack.
c. Call any critical values.
d. Wash their hands.
ANS: D
 As soon as the gloves come off, the technicians must wash their hands to ensure that all
potential pathogens are removed before the technicians touch inanimate objects in the clean
area of the laboratory.

OBJ: Level 3: Synthesis

42. The biosafety levels were categorized using all the following criteria, except
a. the bacterial load necessary to cause infection.
b. the organism’s ability to cause serious illness.
c. the organism’s mode of transmission.
d. whether there is treatment available for an infection.
ANS: A
Bacterial load was not a criterion. The four biosafety levels were derived from categories of
etiologic agents. These categories include the organism’s ability to cause serious illness, the
organism’s mode of transmission, whether there is treatment available for infection, and
whether there are any preventive measures such as vaccines.

OBJ: Level 1: Recall

43. A biosafety level 1 (BSL-1) level of containment is used for organisms that
a. cause 90% mortality of infected people.
b. are well classified and not known to cause disease in healthy people.
c. cause 90% morbidity of infected people.
d. can be transmitted through aerosols.
ANS: B
This is the lowest level of biosafety. These organisms pose a minimal threat to laboratory
personnel and the environment. Laboratory work can be conducted on open bench tops.
Employees should be trained in laboratory procedures and supervised by a scientist with
training in microbiology.

OBJ: Level 1: Recall

44. A biosafety level 2 (BSL-2) level of containment is used for organisms that
a. can cause a catastrophe if released.
b. usually cause 90% mortality in the population.
c. create a moderate potential hazard for employees and the environment.
d. do not cause significant harm to employees and the environment.
ANS: C
These organisms pose a moderate hazard. Guidelines for laboratories that handle these agents
include having a biosafety cabinet, limiting access to the laboratory when cultures are out,
having employees receive immunizations for contact with possible pathogens, having an up-
to-date biosafety manual, wearing PPE, and restricting use of sharp items to times when no
alternative equipment can be used.

OBJ: Level 1: Recall

45. Because biosafety level 3 (BSL-3) organisms have the potential for aerosol transmission, and
diseases with these agents may have serious lethal consequences, all of the following
guidelines apply to BSL-3 laboratories, except:
 a. BSL-3 laboratories should be separated from other parts of the building by an
anteroom.
b. BSL-3 laboratories should have restricted access with documentation of personnel
entering and exiting the laboratory.
c. BSL-3 laboratories should have solid ceiling and floor seams, and any seams must
be sealed.
d. BSL-3 laboratories should have positive air pressure.
ANS: D
BSL-3 laboratories must follow BSL-2 safety guidelines and must also have a class II or III
biological safety cabinet; must ensure that employees wear appropriate PPE; should be
separated from the other parts of the building by an anteroom; should have negative air
pressure and the air from inside the laboratory should be directed outside without
recirculation; should have ceilings and floors that are solid and any seams sealed; and must be
constructed so that all parts of the laboratory can be easily cleaned and disinfected. BSL-4
laboratories should have restricted access.

OBJ: Level 1: Recall

46. Biosafety level 4 (BSL-4) organisms are dangerous, exotic, and pose an increased risk of
aerosol-transmitted infections and life-threatening disease. Two examples of BSL-4 organisms
are
a. Marburg and Congo-Crimean hemorrhagic fever.
b. St. Louis encephalitis virus and Coccidioides immitis.
c. Mycobacterium tuberculosis and Ebola virus.
d. Francisella tularensis and Ebola virus.
ANS: A
The only two BSL-4 organisms listed are Marburg and Congo-Crimean hemorrhagic fever. St.
Louis encephalitis virus, M. tuberculosis, and F. tularensis are all BSL-3 organisms.

OBJ: Level 1: Recall

47. OSHA requires laboratories to have this document to ensure that laboratory personnel have a
thorough working knowledge of the hazards of the chemicals with which they work.
a. Chemical control plan
b. Standard operating procedures
c. Chemical hygiene plan
d. OSHA compliance plan
ANS: C
OSHA regulations require that employees compile a chemical hygiene plan that details the
hazards of the chemicals used in the workplace. This plan must also contain a provision for
hazardous communication training.

OBJ: Level 1: Recall

48. A Material Safety Data Sheet (MSDS) contains all the following information, except
a. The nature of a chemical (flammable, toxic, carcinogenic)
b. General characteristics
c. Precautions when using a chemical
 d. Classification of a chemical (acid, base, protein)
ANS: D
MSDSs document the nature of a chemical (flammable, toxic, carcinogenic), general
characteristics, precautions to take in using a chemical, emergency information, spill cleanup
procedure, and disposal recommendations.

OBJ: Level 1: Recall

49. If a laboratory uses hazardous chemicals, it must

a. keep a chemical inventory and MSDSs on hand.
b. keep chemicals in a special corrosive cabinet.
c. keep chemicals in a special locking cabinet.
d. post chemical names and locations on the door of the laboratory.
ANS: A
A laboratory must maintain a current inventory of hazardous chemicals, and the MSDSs for
those particular chemicals according to 29 CFR Part 1910, Subpart 2, Toxic and Hazardous
Substances (OSHA).

OBJ: Level 1: Recall

50. Laboratory safety for hazardous chemicals includes

a. restricting use of these chemicals to specific individuals.
b. using fume hoods to prevent inhalation of fumes.
c. locking chemicals in one specific “corrosives” cabinet.
d. providing biohazard training to affected individuals.
ANS: B
Laboratory safety for hazardous chemicals includes using fume hoods to prevent inhalation of
fumes, personal protective devices (fume masks, gloves, aprons, and eyewear), acid and
flammable spill kits, and warning signs in appropriate places announcing the hazardous
chemical.

OBJ: Level 1: Recall

51. Most institutions use the RACE acronym to respond to a fire emergency. RACE stands for
a. race, alert, cite, evacuate.
b. run, avoid, call, emergency.
c. rescue, alarm, contain, extinguish.
d. retrieve, announce, close, exit.
ANS: C
RACE stands for rescue (remove anyone who is in danger), alarm (know where the nearest
fire pull box or alarm station is located and know the number to call to report the fire), contain
(close doors to contain fire and smoke), and extinguish (use the properly rated fire
extinguisher on small fires).

OBJ: Level 1: Recall

52. The best way to care for your back is to prevent back injuries. All of the following are some
ways to prevent back injuries, except
 a. carefully lifting heavy objects overhead.
b. using good posture.
c. using the legs to lift, not the back.
d. asking for assistance when a load is too heavy.
ANS: A
Carrying heavy trays of culture plates, lifting heavy loads in and out of autoclaves, and sitting
or standing improperly can all contribute to back stress injuries. Using good posture, using the
legs to lift (not the back), asking for assistance when a load is too heavy, and staying
physically fit all help prevent back injuries.

OBJ: Level 1: Recall

53. Three levels of laboratories outlined in the Laboratory Response Network (LRN) include all
the following, except
a. sentinel.
b. reference.
c. first responder.
d. national responder.
ANS: C
The CDC developed the LRN in 1999 so that laboratories could respond quickly and
effectively to a bioterrorism event. The three levels of laboratories contained in this document
include sentinel, reference, and national responder.

OBJ: Level 1: Recall

54. In the LRN program, hospital-based microbiology laboratories are classified as this type of
laboratory.
a. Reference
b. National
c. Primary
d. Sentinel
ANS: D
There are only 100 reference laboratories in the United States and two national laboratories
(CDC and the SAMRIID). The remaining hospital laboratories are designated as sentinel
laboratories.

OBJ: Level 1: Recall

55. Category A bioterrorism agents

a. pose the highest threat because they are easily transmitted and highly infectious.
b. have moderate morbidity and low mortality and are not easily transmitted.
c. are emerging pathogens.
d. are enteric pathogens.
ANS: A
Category B bioterrorism agents have moderate morbidity and low mortality and are not easily
transmitted. Category C bioterrorism agents are emerging pathogens. Enteric pathogens are
usually considered gram-negative rods.
 OBJ: Level 1: Recall

56. Once bioterrorism is suspected, a sentinel laboratory should perform all culture manipulation
using these safety guidelines.
a. BSL-2
b. BSL-3
c. BSL-4
d. BSL-1
ANS: B
All manipulations should be handled using BSL-3 guidelines, and all work should be done in
a class II or III biological safety cabinet. As soon as possible after a sample has been identified
as a potential bioterrorism agent, it should be referred to the appropriate LRN Reference
laboratory.

OBJ: Level 1: Recall