Question 1

Direct microscopic examinations are not recommended for all the following specimen sources except:

Accepted Answer

A direct microscopic examination from the urethral discharge from a male can be diagnostic for Neisseria gonorrhoeae.This is because the male urethra is considered sterile, so any bacteria, especially intracellular bacteria, would be considered pathogenic.At all the other sites listed, there is much normal flora and the shapes of some of the normal flora can resemble the shapes of pathogenic organisms.

Question 2

Enriched media:

Accepted Answer

Enriched media contain growth enhancers that are added to nonselective agar to allow fastidious organisms to flourish.Nonselective media support the growth of most nonfastidious microbes.Selective media support the growth of one type or group of microbes, but not another.Differential media allow grouping of microbes based on different characteristics demonstrated on that medium.

Question 3

Types of specimens that can be batch processed include all the following except:

Accepted Answer

Specimens for GC cultures involve a very fastidious and fragile organism-Neisseria gonorrhoeae-and these cultures must be processed immediately so as to preserve the bacteria present in the specimen.All other specimens mentioned can be batch processed.

Question 4

The direct microscopic examination is a useful tool for all the following reasons, except it can:

Accepted Answer

A direct microscopic examination can inform a physician if bacteria are present, but it cannot tell the physician if the bacteria are normal flora, nor if they are anaerobic or aerobic.The microscopic examination will show formed elements such as epithelial cells, white blood cells, red blood cells, bacteria, and fungus, but it only shows shapes.

Question 5

All of the following are examples of suboptimal specimens that must be rejected except the:

Accepted Answer

The specimen for a GC culture that is submitted in a JEMBEC system is the correct way to submit that specimen for culture.The rest options are grounds for rejecting the specimen.

Question 6

An enrichment broth is:

Accepted Answer

An enrichment broth is a liquid medium designed to encourage the growth of small numbers of a particular organism while suppressing other flora.Enrichment broths are incubated for a certain period and then must be subcultured to isolate the particular organism.Broth media can be used as a supplement to agar plates to detect small numbers of most aerobes, anaerobes, and microaerophiles.

Question 7

Two types of specimens can use preservatives to maintain them until they can be delivered to the laboratory.They are:

Accepted Answer

The preservatives are designed to maintain the bacterial population in the urine at room temperature for 24 hours and thus are useful for collection of urine specimens at distant locations.Stool specimens for bacterial culture and ova and parasites can be added to a vial containing preservatives to maintain the organisms until they can be transported to the laboratory.Vaginal secretions, throat cultures, and pus from a wound can be placed in a vial containing transport media to maintain the viability of the organisms.

Question 8

A technician receives a package from a supplier of quality control microorganisms.The package has a small watertight vial in a larger watertight tube.The larger tube has some bubble wrap around it, but the larger tube is just placed in the fiberboard box.All of the following was right with this packaging except the:

Accepted Answer

Patient specimens or culture isolates must be triple packaged before being shipped.The material is placed into a primary receptacle that must be watertight.Absorbent material is placed around the primary receptacle and it is then placed into a secondary container that is also watertight.The secondary package is sealed and placed into a sturdy outer container constructed of fiberboard.

Question 9

The purpose of transport media is to:

Accepted Answer

The purpose of transport media is to maintain the viability of the bacteria in the specimen.These materials do not want to promote multiplication because the metabolic by-products (i.e., acids) may build up and kill the bacteria.These media do keep the swab moist, but this is not their purpose.Also, the use of transport media is to do just that-ensure viable organisms during transport.They will never take the place of a routine culture.

Question 10

The shipment of clinical specimens and cultures of microorganisms is governed by a complex set of national and international guidelines issued by The Department of:

Accepted Answer

The Department of Transportation prescribes regulations for the safe transportation of hazardous material in commerce to ensure public safety and minimize risks in transportation.The regulations specify the way potentially infectious substances must be packaged to prevent leaks or spills, and how the packages must be labeled to caution handlers and other parties about their hazardous content.The U.S.Postal Service reinforces these transportation regulations.

Question 11

In certain instances, it is desirable for specimens to be inoculated directly onto culture media.Specimens for this pathogen can be placed onto a commercial transport system called a JEMBEC system.What pathogen is this?

Accepted Answer

The JEMBEC system was developed specifically for transporting culture media inoculated with specimens for N.gonorrhoeae (GC) cultures.This method of transport increases the yield of organisms recovered from cultures.This system consists of a media selective for Neisseria spp., a Ziploc plastic bag, and a tablet.The tablet is added to the proper spot, a couple drops of water are added to the table, then the cover is placed on the media.The entire plate is inserted into the plastic bag and sealed so that an atmosphere high in carbon dioxide can be generated.

Question 12

Notations from the macroscopic (gross) examination of a specimen should include all the following except:

Accepted Answer

The gross appearance of the specimen may provide useful information to both the microbiologist and the physician.The physical characteristics of the specimen should be documented so that if different technologists work on the sample, they will all know the results of the gross examination.This gross examination also allows the processor to determine the adequacy of the specimen and the need for special processing.The type of the container in which the specimen was received has nothing to do with the macroscopic/physical/gross appearance of the specimen.

Question 13

How does the Department of Transportation (DOT) define an infectious substance?

Accepted Answer

The DOT defines an infectious substance as material known to contain or is suspected of containing a pathogen that causes disease in humans or animals.An infectious substance is assigned to a risk group with a number from 1 (low risk) to 4 (high risk).The substance must be capable of transmitting disease to human or animals.It can be bacterial spores that are not considered a bacterium, virus, prion, or virion.

Question 14

Differential media:

Accepted Answer

Differential media allow grouping of microbes based on different characteristics demonstrated on that medium.Nonselective media support the growth of most nonfastidious microbes.Selective media support the growth of one type or group of microbes, but not another.Enriched media contain growth enhancers that are added to nonselective agar to allow fastidious organisms to flourish.

Question 15

All of the four levels represent a possible scheme for prioritizing the handling of specimens, except level:

Accepted Answer

Level 4: specimens that are arriving in transport media.Level 1: critical because the specimens represent a potential life-threatening illness and are from an invasive source.Level 2: unprotected; may quickly degrade or have overgrowth of contaminating flora.Level 3: requires quantitation, and a delay in processing may adversely affect the accuracy of quantitation.

Question 16

Nonselective media supports the:

Accepted Answer

Nonselective media support the growth of most nonfastidious microbes.Selective media support the growth of one type or group of microbes, but not another.Differential media allow grouping of microbes based on different characteristics demonstrated on that medium.Enriched media contain growth enhancers that are added to nonselective agar to allow fastidious organisms to flourish.

Question 17

How is culture media selected for specimen plating?

Accepted Answer

The selection of media to inoculate is based on the type of specimen submitted for culture and the organisms likely to be involved in the infectious process.Specimens in which fastidious pathogens are more likely involved require media with appropriate nutrients to aid in their recovery.Specimens that are collected from a site containing normal flora will require types of media to diminish the normal flora while allowing the pathogens to be detected.

Question 18

The technician in the laboratory has received a specimen that is rejected.The technician calls the physician and tells the physician the specimen is unacceptable and the reason why.The physician insists that the culture needs to be performed on this unacceptable culture.What should the technician do?

Accepted Answer

Physicians can be very insistent that laboratory tests be performed on suboptimal or unacceptable specimens.The best thing for the laboratory technician to do is to perform the requested test, include a comment that the specimen was suboptimal or unacceptable, and bring this matter to the pathologist.The pathologist will usually speak to the physician about the matter and take care of the problem.

Question 19

Selective media:

Accepted Answer

Selective media support the growth of one type or group of microbes, but not another.Nonselective media support the growth of most nonfastidious microbes.Differential media allow grouping of microbes based on different characteristics demonstrated on that medium.Enriched media contain growth enhancers that are added to nonselective agar to allow fastidious organisms to flourish.

Question 20

Specimens such as blood, bone marrow, and synovium are mixed with anticoagulants right after collection.Why should this occur?

Accepted Answer

When a specimen clots, many of the pathogens are trapped inside the clotted blood.This makes it more difficult to determine the cause of the infection.Anticoagulants do not dissolve bacterial cell walls, but they do have a certain degree of antimicrobial properties.Very small amounts must always be used to ensure that this compound does not kill any bacteria present in the specimen.

Quiz 6: Specimen Collection and Processing