MA 4: chapter 49

A urinary tract infection can be diagnosed if an organism isolated from a CCMS urine specimen is found in pure culture and is present in a quantity greater than:

100,000 cfu/mL of urine

Which of the following cfu results would indicate a UTI is likely?

100,000 cfu/mL of urine

Acid-Fast Stain

A staining procedure for identifying bacteria that have a waxy cell wall.

Beta hemolysis: - is best detected on a sheep's blood medium. - is caused by hemolysis of blood cells. - refers to a clear zone around bacterial colonies growing on a sheep's blood medium. - all correct

All are correct

Which of the following CLIA-waived serology tests can be performed by a medical assistant to detect antibodies to a specific pathogen? Infectious mononucleosis H. pylori Lyme disease HIV All are correct

All are correct

An organism that is unlikely to be transmitted by sexual contact is:

Clostridium botulinum

An organism that is unlikely to be transmitted by sexual contact is: Neisseria gonorrhoeae. T. pallidum. Chlamydia trachomatis. Clostridium botulinum.

Clostridium botulinum - is transmitted by contaminated food.

Legionnaires' disease is caused by a Gram-positive bacillus that causes a particular type of pneumonia.

Falae - Legionnaires' disease is caused by a Gram-negative bacillus that causes pneumonia-like symptoms.

Mycoplasmas have more PG in their cell walls than any other pathogen

False

The physician would order a stool culture to confirm staphylococcal food poisoning.

False Staphylococcal food poisoning cannot be diagnosed from a stool culture, because the organism is not found in the stool

Mycobacterium tuberculosis is the organism that causes tuberculosis and also is an anaerobe.

False - Mycobacterium tuberculosis is an aerobe and an acid-fast bacillus.

Specimens should be collected during the acute phase of an illness and 24 hours after antibiotics are prescribed.

False - Specimens should be collected before antibiotics are prescribed to make sure the microorganism can be cultured if necessary.

Mycoplasmas have more PG in their cell walls than any other pathogen.

Fasle - Mycoplasmas are unusual in that they have no PG in the cell wall, but they are not obligate parasites, as are rickettsiae and chlamydiae.

Fungi are classified as:

Fungi are eukaryotes and are either single-cell or multicellular organisms with a nucleus that is membrane bound.

The rapid detection test that assists in the diagnosis of stomach ulcers detects:

Helicobacter pylori

The term which means "in glass" or "in the laboratory" because it is not occurring in a living body.

In vitro

Which of the following tests is performed in the serology laboratory? Direct immunologic urine pregnancy test Indirect immunologic tests Strep test Influenza test

Indirect immunologic test

Gram stain

Most commonly used stain in the microbiology laboratory •Gram-positive bacteria stain purple; . gram-negative bacteria stain pink or red

Staining

Pathogenic microorganisms generally are colorless, and a microscope is needed •Differential stains are used to differentiate bacteria based on biochemical differences •Bacteria first applied to the labeled slide •Slide is air dried and fixed

Which of the following infections is caused by a fungus? Pneumocystis pneumonia Pyloric ulcers Rocky Mountain spotted fever Toxic shock syndrome

Pneumocystis pneumonia Because it is a fungal infection that is frequently seen in AIDS patients.

A tiny, Gram-negative organisms transmitted by blood-sucking insects.

Rickettsiae

Referring to antimicrobial susceptibility testing, which of the following labels would indicate that the antibiotic is effective against the organism in that particular concentration in vitro?

S

Referring to antimicrobial susceptibility testing, which of the following labels would indicate that the antibiotic is effective against the organism in that particular concentration in vitro? S R I None

S - S means that the pathogen is "susceptible," or that the antibiotic is effective against the organism in that particular concentration in vitro; - R means that the organism is "resistant" to the antibiotic; - I means "intermediate," that is, additional testing must be performed to determine the dosage of antimicrobial necessary for therapeutic treatment.

Microbiology Culture and Sensitivity Testing

S: Means pathogen is "susceptible" ➢R: Means that organism is "resistant" ➢I: Means "intermediate" (additional testing must be performed)

Which of the following will need a blood sample for diagnosis? Salmonella Tetanus Strep throat All are correct

Tetanus

An organism that is unlikely to be transmitted by airborne droplets is:

Treponema pallidum

A Gram-positive cell has a thick layer of peptidoglycan with no lipid layer surrounding it.

True

A chlamydia specimen must be transported to the laboratory on ice immediately after collection.

True

A stool for O&P is used to diagnose both amoebic dysentery and giardiasis.

True

Bacterial endospores allow a microorganism to survive harsh environments.

True

Cultures for gonorrhea should be kept at room temperature.

True

Most pathogenic organisms prefer temperatures around 37°C and remain viable for up to 72 hours if held at room temperature or refrigerator temperature.

True

Negative rapid strep test results must be confirmed with a throat culture, because the rapid strep test is highly specific but not highly sensitive.

True

Tetanus is caused by a spore-forming, anaerobic bacillus that is most likely to be seen in deep wounds

True

The Epstein-Barr virus causes mononucleosis.

True

Tinea pedis is a fungal infection of the feet.

True

Malaria is diagnosed from a stained blood sample that is examined under the microscope for the protozoal parasite.

True - Malaria is a parasitic infection that is spread by a vector (mosquito) and is diagnosed by a stained blood sample.

Common Diseases Caused by Bacteria

Tuberculosis Urinary tract infections Legionnaires' disease Tetanus

A cellulose tape test for pinworms requires:

a length of cellulose tape to be touched against the anal folds to collect worms and a microscope to view the eggs that have adhered to a length of cellulose tape.

Sensitivity testing is used to determine: - the susceptibility of a microorganism to antiviral treatment. - the patient's susceptibility to a particular pathogen. Correct Answer - a pathogen's susceptibility to a particular antibiotic. - All are correct

a pathogen's susceptibility to a particular antibiotic.

An anaerobic organism is most likely to be isolated from a(n):

abscess

Bacteria that require oxygen to live are called

aerobic

throat culture

also known as group A strep (GAS), causes strep throat •Throat swab is streaked for isolation on a blood agar plate (BAP)

Bacteria that die in the presence of oxygen are

anaerobes

Fungi

are eukaryotes that include unicellular yeasts and multicellular molds •Transmitted by direct contact with an infected person, prolonged exposure to moist environment, and inhalation of contaminated dust or soil

Protozoa

are single-celled, in contaminated food, drinks, feces

Members of a class of invertebrate animals that include insects, crustaceans, and arachnids.

arthropod

When writing the name of a microorganism, which of the following rules applies to the genus?

begins with a capital letter and may be represented by a single letter

Which of the following pathogenic organisms can be identified in sputum samples?

both A and B pathogenic fungi , pathogenic parasites

The Gram reaction a bacterium exhibits are the result of its:

chemical makeup of the cell wall.

Viruses

consist of a core of either ribonucleic acid (RNA) or deoxyribonucleic acid (DNA) covered by a protein shell •Viruses must be cultured in fertilized eggs or in a tissue culture

An organism that is flexible as far as its oxygen requirements are concerned is called a(n):

facultative anaerobe

Rickettsiae

gram-negative, transmitted by blood-sucking arthropods

Which are not considered microorganisms? Bacteria Fungi Rickettsiae All are correct

helminths

The prefix staphylo- means that bacteria appear: in coiled springs. rod shaped. in grapelike clusters. in pairs.

in grapelike clusters.

Gram-negative bacteria will stain what color?

pink/red

Microscopically, a sputum specimen containing positive AFB appears:

pink/red

Microscopically, a sputum specimen containing positive AFB appears:

pink/red - After staining in the acid-fast stain, acid-fast-positive bacteria (AFB) stain pink-red or fuchsia-red, and acid-fast-negative bacteria stain bay blue

Bacteria are classified as:

prokaryotes

The growth of only one microorganism on a nutrient surface or culture is the definition for which of the following terms or phrases?

pure culture

In the scientific name Escherichia coli, the name coli indicates the:

species

Tightly coiled, spiral-shaped bacteria are called:

spirochetes

When bacteria are found in grapelike clusters, which of the following prefixes is used?

staphylo

Infectious Mononucleosis Testing

•Testing involves a complete blood count (CBC) and serologic tests •Increased number of lymphocytes that appear atypical •Most patients exposed to the Epstein-Barr virus (EBV) develop a nonspecific antibody response to the virus

Three types of cell wall structures are found among pathogenic bacteria

➢Gram-positive cells ➢Gram-negative cells ➢Acid-fast cells

Pathogenic bacteria assume three different shapes:

➢Round bacteria called cocci ➢Rod-shaped bacteria called bacilli ➢Spiral-shaped bacterial called spirilla

Specific structures inside a cell that perform cellular functions.

organelles

Molecules that are needed for metabolism, examples include carbohydrates, lipids, and proteins.

macromolecules

Helminths

multicellular parasitic organisms commonly called worms or flukes