[PSM] Brock Chapter 27, 31

Food Micro, Diagnostic Micro

Vibrio cholerae

a gram-negative, curved rod of the Phylum Proteobacteria that is usually transmitted via contaminated water

Water

The MOST important potential common source of infectious disease is?

C) nonperishable

Flour and sugar are classified as ____ foods.

A) highly perishable

B) semiperishable

C) nonperishable

D) selectively perishable

Psychrotolerant microorganisms

Microorganisms that can survive and grow at refrigeration temperatures

Neutral or acidic

The pH of most foods is ?

B) reduce water activity (aw).

The principle behind salt or sugar preservation is to

A) introduce a mechanical barrier to microbial invasion.

B) reduce water activity (aw).

C) introduce a microbicide in anticipation of contaminating bacteria or fungi.

D) accomplish all of the described functions depending on the food being preserved.

weak acids

Pickling is a type of food preservation utilizing?

Superantigen toxins

S. aureus toxins are classified as what types of toxins?

B) for dehydration.

Severe cases of Staphylococcus aureus food poisoning may require treatment

A) with powerful antibiotics.

B) for dehydration.

C) with cleansing enemas.

D) for dehydration, along with powerful antibiotics and cleansing enemas.

Clostridium perfringens

Pathogen that causes diarrhea by altering the permeability of the intestinal epithelium through the toxin it produces

C) positive endospore-forming / exotoxin

Clostridium botulinum is a gram- rod that produces an

A) negative / endotoxin

B) negative / exotoxin

C) positive endospore-forming / exotoxin

D) positive endospore-forming / endotoxin

Salmonella enterica serovar Typhimurium and Enteriditis

What are the serovars that frequently cause Salmonellosis?

A) hemorrhagic diarrhea.

Verotoxin can cause

A) hemorrhagic diarrhea.

B) liver failure.

C) brain damage.

D) hemorrhagic diarrhea, liver failure, and brain damage.

D) labile / enterotoxins

ETEC strains produce one of two heat-___ diarrhea-producing___

A) stable / endotoxins

B) labile / endotoxins

C) stable / enterotoxins

D) labile / enterotoxins

C) microaerophiles.

The Campylobacter spp. are

A) aerobes.

B) anaerobes.

C) microaerophiles.

D) facultative anaerobes.

Acid, Cold, Salt

L. monocytogenes is tolerant to which substances or characteristics?

D) blood or spinal fluid / intravenous antibiotics

Listeriosis is diagnosed from cultures and treated with

A) sputum / intravenous antibiotics

B) blood or spinal fluid / hydration therapy

C) sputum / hydration therapy

D) blood or spinal fluid / intravenous antibiotics

B) radiation.

To prevent the spread of pathogens that cause listeriosis, raw food and food -handling equipment can be decontaminated with

A) antibiotic spray.

B) radiation.

C) cold storage.

D) antibiotic spray, radiation, and cold storage.

B) fungi

What organisms are good competitors for free water present in foods with low aw?

A) gram-positive cocci

B) fungi

C) gram-negative bacilli

D) gram-positive bacilli

B) decreases

When solute is added to food products, the water activity (aw)

A) increases.

B) decreases,

C) remains the same.

D) initially increases and then decreases.

7:5%

With the exception of some gram-positive cocci, what concentration of NaCl inhibits nearly all bacterial growth?

Herbs and spices

Which items are MOST routinely irradiated in the United States?

B) sulfuric acid bacteria

Which organisms are NOT involved in food fermentations?

A) lactic acid bacteria

B) sulfuric acid bacteria

C) acetic acid bacteria

D) propionic acid bacteria

C) nonacid, home-canned vegetables.

The MOST common source of individual foodborne botulism outbreaks are due to consumption of

A) honey.

B) dairy products.

C) nonacid, home-canned vegetables.

D) egg and meat salads.

A) enterohemorrhagic

The type of Escherichia coli that produces a verotoxin similar to the one produced by Shigella dysenteriae is E. coli.

A) enterohemorrhagic

B) enterotoxigenic

C) enteropathogenic

D) enteroimmunogenic

C) direct contact.

The MOST common route of transmission of Salmonella typhi worldwide is through

A) contaminated food.

B) contaminated water.

C) direct contact.

D) insect vectors.

B) small intestine.

Vibrio cholerae primarily infects the

A) stomach.

B) small intestine.

C) large intestine.

D) rectum.

C) contaminated water in coolers, pools, and domestic water systems.

Legionella pneumophila is generally transmitted by

A) contaminated food.

B) contaminated drinking water.

C) contaminated water in coolers, pools, and domestic water systems.

D) person—to-person contact.

B) eosin-methylene blue agar

What is the medium used in the membrane filter (MF) procedure to differentiate fecal coliforms and Escherichia coli?

A) mannitol salt agar

B) eosin-methylene blue agar

C) triple sugar iron agar

D) blood agar

Intravenous erythromycin

Infection with Legionella pneumophila is usually treated with [__]?

FALSE

T/F: All coliforms are pathogenic

FALSE

T/F: Acidic foods generally need a higher canning temperature than do nonacidic foods.

TRUE

T/F: Properly canned foods are not automatically sterle

Food Poisoning or Food Intoxication

This generally results from the ingestion of food containing microbial toxins.

Food Infection

This result from the ingestion of pathogen-contaminated food

TRUE

T/F: Antibiotics are not normally used to treat either food poisoning or food infection

FALSE

With Clostridium perfringens, the enterotoxin is present in the endospores that germinate under anoxic conditions.

FALSE, 85 deg C for 5 minutes

T/F: To be certain the botulinum toxin is inactivated, the source must be heated for at least 2 minutes at 100°C.

FALSE

T/F: Gram-negative bacteria are responsible for causing MOST foodborne diseases.

Campylobacter

Infections by this bacteria are the most common foodborne infections in the US

Perishable

Food that is generally fresh and with high water activity

Semiperishable

Food with a lower water activity or have been preserved in some way

Nonperishable

Food with a very low water activity and can be stored for long periods of time without spoilage

Most Probable Number (MPN) Procedure

Procedure for detecting coliform concentration wherein a water sample is added into a defined liquid culture medium where it is incubated to observe growth (and therefore presence) of particular organisms.

Membrane Filter (MF) Procedure

Procedure for detecting coliform concentration which involves filtering a water sample such that the microbial cells are trapped onto the filter, and the filter is placed onto a differential and selective growth medium such as a eosin-methylene blue (EMB) agar plate.

B) BSL-2.

Laboratories that work with moderate risk pathogens are classified as
A) BSL-1.

B) BSL-2.

C) BSL-3.

D) BSL-4.

Bacteremia

A term used to indicate the presence of bacteria in the blood

B) Complementary DNA must be synthesized from RNA.

Which of the following must be accomplished FIRST in order to conduct RT-PCR?

A) Complementary DNA must be synthesized from double-stranded DNA.

B) Complementary DNA must be synthesized from RNA.

C) Complementary DNA must be synthesized from proteins.

D) Complementary DNA must be synthesized from single-stranded DNA.

C) urinary tract

The most common of all nosocomial infections are infections.

A) blood

B) reproductive tract

C) urinary tract

D) respiratory tract

Selective and Differential Media

What type of media are MacConkey and EMB agar?

Minimum Inhibitory Concentration

An Etest is a clinical tool used for the determination of the [__] of an antimicrobial agent

Heat-lysed blood cells

What component enriches chocolate agar?

Thayer-Martin agar

A specialized growth medium used to isolate and cultivate Neisseria bacteria

Nitrogen and carbon dioxide

During an anoxic incubation of a bacterial culture, the oxygen-free gases that are commonly employed are?

B) differential but not selective

Which type of medium typically contains an indicator dye?
A) selective but not differential

B) differential but not selective

C) both selective and differential

D) neither selective nor differential

A) fluorescent antibody (FA)

Which of the following immunological tests would allow the specific identification of a microorganism directly in a patient specimen?

A) fluorescent antibody (FA)

B) radioimmunoassay (RIA)

C) enzyme-linked immunosorbent assay (EIA)

D) agglutination

Targets the 30S ribosomal subunit

What is the mechanism of aminoglycoside?

Azole

Drug for treating Candida

Western blot

Blotting of proteins from polyacrylamide gels to nitrocellulose paper and subsequent identification by specific antibodies

Horizontal Gene Transfer

How is widespread antimicrobial drug resistance passed?

R plasmid

Most drug resistant bacteria isolated from patients contain a?

Antibody titer

What does agglutination measure?

General purpose

Blood agar is an example of what type of medium?

Nonselective Enriched media

Chocolate agar is an example of?

delayed hypersensitive (DTH) TH1 cells

The tuberculin skin test looks to identify [__] specific to M. tuberculosis?

Staphylococcus

Protein A, commonly used in immunoblots, is derived from?

Antibiograms

Periodic reports on the susceptibility of clinically isolated organisms to the antibiotics in current local use

Sensitivity

Defines the lowest quantity of an antigen that can be detected in a serological test

Quinolones

Antibacterial class that prevents supercoiling of bacterial DNA

A) with penicillinase-resistant B-lactams

How is drug-resistant Neisseria gonorrhoeae treated?

A) with penicillinase-resistant B-lactams

B) with tetracycline

C) with synthetic analogs of tetracycline

D) with vancomycin

C) portions of the oral cavity

Obligately anaerobic normal flora are found in the body.

A) the kidneys

B) the skin

C) portions of the oral cavity

D) the lungs

Antibody

Protein A has a strong affinity for ?

A) Reverse transcription PCR

Which is used to monitor gene expression of a pathogen?

A) Reverse transcription PCR

B) Serology

C) Antigen capture assay

D) Qualitative PCR

A) single-stranded

Hybridization requires a nucleic acid probe that binds to DNA or RNA of interest, which must be in the ___ form for hybridization to occur.

A) single-stranded

B) double-stranded

C) oligomerized

D) polymerized

C) rifampin

Which of the following antibiotics inhibits RNA synthesis?

A) penicillin

B) erythromycin

C) rifampin

D) azithromycin

B) dsDNA

SYBR Green, commonly used in qPCR, binds nonspecifically to

A) ssDNA

B) dsDNA

C) ssRNA

D) dsRNA

Direct EIA

Type of Enzyme IA: antigen is immobilized on a solid support, and a labeled antibody (conjugated to an enzyme) is added directly to detect the antibody in the sample

Indirect EIA

Type of Enzyme IA: the antigen is also immobilized. First, the patient's serum (containing the antibodies) is added. After washing, a labeled secondary antibody (e.g., anti-human IgG) that binds to the primary antibody is added. This amplifies the signal, making it more sensitive

Sandwich EIA

Type of Enzyme IA: Utilizes two antibodies to surround the target antigen, allowing for accurate measurement