Microbio 31, 32 (LC

attack rate

(infected + those with symptoms) / (total people)

Cholera toxin = A-B subunits - order of what occurs?

B attaches to cell w/ cell receptor toxin enters cell using endocytosis, subunits separate A alters cell function, B leaves cell

Which bacteria involved in food infections produce toxins to cause host damage? Escherichia coli, Salmonella, Listeria, Campylobacter

E coli, salmonella

tapeworm associated with undercooked pork?

T. solium

How do pseudohyphae in yeasts differ from vegetative hyphae in filamentous fungi?

Yeasts use pseudohyphae to invade host tissue, whereas filamentous fungi use their vegetative hyphae for obtaining nutrients.

Which of the following could Tori's physician choose as a treatment for her yeast infection? a topical over-the-counter ointment, such as clotrimazole or miconazole an antiviral medication, such as acyclovir a single oral dose of fluconazole an oral narrow-spectrum antibiotic, such as penicillin G

a topical over-the-counter ointment a single oral dose of fluconazole (antifungals)

Sequence of events in tapeworm infection?

adult tapeworms in definitive host produce eggs - eggs released to env in feces - - pigs eat this human feces - - - grow in pig muscles - - - - definitive host eats this meat and is infected

Naegleria fowleri is a free-living ________ that causes infection by ________.

ameoba / crawls into nose and buries in brain

destroying erythrocytes

anemia

Staphyloccocus aureusL: food poisoning. Genes associated with S. aureus encode exotoxins associated with food poisoning. SEA is a S. aureus exotoxin encoded by a viral gene. What sort of life cycle must the phage have?

lysogenic

Which of the following is an example of a secondary systemic mycosis?

cryptococcosis that develops in the lungs of a patient with HIV/AIDS

The visceral parasites that are of great concern to people with compromised immune systems include __________.

cryptosporidium

Enteric bacteria such as Salmonella spp., Shigella spp., and Escherichia spp. most often contaminate and spoil

meat

Leishmania parasites live within leukocytes. Which type of cell is most likely to harbor them? natural killer cells plasma B cells macrophages memory B cells

plasma B cells

Clostridium botulsim is a gram ____, ______ rod that produces ______

positive, endospore forming exotoxin

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

radiation

Vibrio cholerae primarily infects the

small intestine

pressure cooker? green beans?

steam makes higher-pressure environment --> food to cook at higher temp --> kill most contaminating microbes and endospores and therefore effectively sterilize the food. also boiling

Athlete's foot is a

superficial fungal infection

Which of the following correctly describes a method of chemical control used to control microbial growth? Surface-active agents, or surfactants, decrease surface tension among molecules of a liquid. Phenolics exert antimicrobial activity by injuring lipid-containing plasma membranes, which causes the cellular components to leak out of the cell. Alcohols exert their action by denaturing proteins and dissolving lipids. High pressure is used to denature proteins in vegetative cells.

surface-active agents phenolics alcohols

Which fungal genus is correctly matched to the class of disease it causes? systemic mycosis: Sporothrix subcutaneous mycosis: Microsporum systemic mycosis: Candida superficial mycosis: Aspergillus

systemic mycosis: Candida

steps in Clostridium perfringens poisoning

- sporulation and lysis of vegetative cells result in release of CPE - CPE binds to claudin receptors of tight junctions of intestine - absorbtion of fluid across junctions inhibited - forming CPE-claudlin complex: pore formation - Ca ion influx activates calpain - cell death of epithelial layer --> diarrhea - myoelectrical activity --> cramping

Staphylococcus aureus is a common foodborne disease, because it (3)

-grows on many foods -is present in some humans that work in food processing -produces several heat-stable enterotoxins.

cholera process of infection

-ingested via contaminated water -survives acid stomach/immune sys and reaches intestine -attaches to pilli and then produces toxin - host intestinal cells are killed --> watery diarrhea -cholera exits via feces

properties of exotoxins? Exotoxins are extremely heat stable. target specific cellular structures or molecules. released from the cell during death or replication. Very small amounts of exotoxin can be lethal. produced primarily by gram-negative bacteria. Exotoxins are protein molecules.

-target specific cellular structures or mol (like cholera attached to G protein so disrupts signalling pathways, imbalance of electrolytes - water into intestines- diarrhea) - very small amounts = lethal - are proteins

The Plasmodium life cycle is very complex, involving two hosts. Which of the choices shows the correct sequence of events in this cycle? 1. Red blood cells are infected. 2. Mosquito bite occurs. 3. Plasmodium enters the liver. 4. Red blood cells are destroyed. 5. Plasmodium grows and develops sporozoites.

2, 5, 3, 1, 4, 2

Why would a tapeworm infection in other areas be concerning?

=escape the stomach, they can travel tomuscles, the liver, the eye, and brain to form cysticerci. =T. solium in the brain--> neurocysticercosis, a serious condition like brain tumors or epilepsy.

reason for supplementing antibiotic therapy for cholera?

Antibiotic therapy addresses only the growth of V. cholerae; it doesn't address the extreme dehydration suffered by a person infected with V. cholerae. - need rehydration treatments

Why are antibiotics often ineffective in treating food poisoning (food intoxication)?

Antibiotics target bacteria; they do not damage toxins.

How do blastoconidia and chlamydoconidia produced by yeast differ from bacterial endospores? Blastoconidia and chlamydoconidia are male and female mating structures used for reproduction in yeasts, whereas bacterial endospores are asexual reproductive structures. Blastoconidia and chlamydoconidia are produced only by yeasts in extreme conditions, whereas bacterial endospores are asexual reproductive structures. Blastoconidida and chlamydoconidia are identical to endospores. Blastoconidia and chlamydoconidia are spore structures produced by budding in yeasts, whereas bacterial endospores are produced by bacteria under extreme conditions.

Blastoconidia and chlamydoconidia are spore structures produced by budding in yeasts, whereas bacterial endospores are produced by bacteria under extreme conditions.

Which of the pairs below are matched correctly for these clostridial pathogens involved in food poisoning? C. perfringens: requires only a small number of cells to produce toxin C. botulinum: must grow in the body to produce toxin C. perfringens: produces enterotoxin C. botulinum: produces endotoxin

C. perfringens: produces enterotoxin

salted candied food doesn't need to refridgerate y?

Extremely concentrated solutions are very hypertonic and therefore desiccate microorganisms. As a result, there is no need for lower temperatures through refrigeration to slow growth.

function of fermentation for the microbes?

Fermentation regenerates NAD+ so that glycolysis can continue.

Heat or water sensitive items can't be sterilized this way - so how? Filtration is the passage of a liquid or a gas through a screenlike material with pores small enough to retain microorganisms. A vacuum is typically used to force the liquid through the mesh, and then the sterile liquid or gas is collected in a sterile container on the other side. Nonionizing radiation, such as UV light, has a wavelength longer than that of ionizing radiation. The wavelengths of UV light are absorbed by cellular DNA in organisms directly exposed to the light. Desiccation is a process that removes water from microorganisms, leaving them unable to grow or reproduce, but still viable. Osmotic pressure is a process that uses high concentrations of salts and sugars to preserve food.

Filtration, nonionizing radiation

antifungal treatments may affect own cells b/c

Fungal cells and human cells have a nucleus, multiple organelles, and 80S ribosomes for protein synthesis.

Which of the following human mutations correlates with resistance to plasmodial infections in West Africa?

Hemoglobin S, class I and class II genes

Why was IgE found in the blood serum?

IgE is the class of antibodies involved in hypersensitivities such as allergies and parasitic infections.

Amphotericin B is an antifungal medication. What might its mechanism of action be? It binds to ribosomes. It prevents synthesis of peptidoglycan cell walls It binds to ergosterol. It binds to phospholipids in fungal membranes

It binds to ergosterol.

The human parasitic infection caused by a protozoan that enters through the nose is caused by __________. Entoamoeba histolytica Ballantidium coli Naegleria fowleri Giardia intestinalis

Naegleria fowleri

Treatment for tapeworms

Praziquantel or albendazole, drugs that target eukaryotic parasites with minimal side effects in the host.

how did yeast infection appear?

The antibiotics removed some normal bacterial flora, resulting in an overgrowth of other organisms.

Humans are incidental hosts for ________, thus infected humans CANNOT spread the disease.

Toxoplasma gondii

Which of the following choices matches a hemoflagellate to its proper insect vector? Leishmania: tsetse fly Trypanosoma brucei: sandfly Trypanosoma cruzi: kissing bug

Trypanosoma cruzi: kissing bug

On a global scale, the most important waterborne bacterial pathogens are __________.

Vibrio cholerae and Salmonella enterica serovar Typhi

The MOST important potential common source of infectious disease is

WATERRRR

vaginal discharge, foul odor and cheesy consistancy, and growth on sabouraud dextrose agar,

candida albicans

The family consumed botulism toxin in the chicken, canned tomatoes, canned green beans,spinach salad.

canned green beans b/c canned (not tomatoes b/c too acidic for botulism to survive)

The degree of susceptibility a food has to microbial activity is determined by its

chemical characteristics, physical characteristics, and water content

Giardia cysts are able to withstand

chemical disinfection

Cryptosporidium parvum is highly resistant to

chlorine

In the US, cholera most often from

contaminated shellfish

Legionella pneumophila is generally transmitted by

contaminated water in coolers, pools, domestic water systems

Fungi that can grow in a yeast or a mold form depending on the conditions are termed __________.

dimorphic

You are examining a sample to determine whether there is a pathogen present that might explain symptoms in a patient. You find a unicellular organism that lacks mitochondria, having mitosomes instead. It has a flagellum and a nucleus. What is it?

euk protist (b/c nucleus)

Which of the following are requirements for Vibrio cholarae causing disease within a host?e evasion of host defenses production of exotoxins adherence to host tissues depleting the host of nutrients at the site of infection direct damage of host tissues gaining access to the host via a portal of entry

evasion of host defenses, adherence to host tissues, gaining access to the host via a portal of entry

In the developed countries of the world, MOST intestinal infections are transmitted via

food

ingestion of pathogen-contaminated food-->

food infection

Psychrotolerant microorganisms can survive and grow at

fridge temps

Why high ID50 for cholera?

has to survive host immune system and acidity of stomach to establish infection

Staphylococcus aureus is dangerous organism when in food due to the enterotoxins which are dangerous b/c

heat stable, acid tolerant, superantigen

Which items are MOST routinely irradiated in the United States?

herbs and spices

Which of the findings listed below support the hypothesis? Oxidative metabolism of glucose by ileum cells occurs at a constant rate as toxin levels are increased. Histological observation indicates that morphological alteration and sloughing of epithelial cells occurs up to a maximum of 1000 units. Protein levels within the ileum loop fluid are increased up to 1000 units of toxin. Increasing levels of sodium, potassium, bicarbonate, and chloride ions, as well as water, are secreted as toxin concentrations are increased from 25, 50, 100, and 150 units.

histological observations protein levels increasing levels of Na, K etc.

Trypanosoma and Leshmania species are transmitted by

insect vectors

- Malaria is (most?) common cause of death due to infectious diseases worldwide - can be controlled by reducing mosquitos? -treated with ...

most yes can be reduced by controlling mosquitos and prevented or treated with chloroquine.

ALL fungal infections can broadly be termed

mycoses

LEAST characteristic of Clostridium perfringens food poisoning? sudden onset of diarrhea severe abdominal cramping short incubation period moderate vomiting and fever

no vomiting or fever

90% of all foodborne illnesses

norovirus, Salmonella, Clostridium perfringens, and Campylobacter jejuni

why study stool samples? Asia, Latin America, Africa sickness from...

observe microscopically for parasites, tapeworm pieces can pass through feces / foodborne

Legionella pneumophilia not found in..spas, hot water tanks, swimming pools, ocean water

ocean water

A major cause of helminthic infectious blindness is

onchocerciasis

Which of the following infections are also caused by C. albicans? syphilis oral thrush genital warts fulminating disease

oral thrush and fulminating disease (yeast into bloodstream, happens with HIV patients)

which caused outbreak overcrowded steam table and, as a result, did not reach an appropriate temperature to kill any organisms. The cooler not atappropriate temperature. The meat was not cooked properly. Large quantities of meat were prepared and kept warm for a long time before they were served.

overcrowded steam table lots of meat kept warm a long time before served

Entamoeba histolytica, transmitted by contaminated food, grows on and in the cells lining the intestine and later within the intestinal wall. This results in dysentery. What best describes the relationship between E. histolytica and its host?

parasitic

T/F The ID50 value refers to the number of microbes needed to cause half of an infected population to die. The terms pathogenicity and virulence can be used interchangeably to describe the severity of an infection. Some pathogens are able to cause disease within a host without penetrating the body. Bacterial exotoxins can be altered to create toxoids, which can be used to produce protective immunity in a host. Intoxications result from a bacterial infection in which a large amount of bacterial toxin is produced. The interactions that occur between a microbe and host influence the evolution of both.

pathogens can cause disease w/o penetrating body exotoxins can be altered to create toxoids to produce protective immunity in a host interactions b/t microe and host influence the evo of both

Visceral leishmaniasis is ? and caused by

the most fatal form of leishmaniasis / Leishmania donovi

During malarial infection, splenomegaly can occur. What causes this? The spleen becomes enlarged in response to fever. The malarial sporozoites colonize the spleen and cause inflammation. The spleen always enlarges in response to infection. The spleen filters the blood and destroys old erythrocytes.

the spleen filters the blood and destroys old erythrocytes

All ate source of disease but not all sick why?

those who became ill ate larger portions of it

Trichomoniasis vaginalis is a sexually transmitted disease that can also survive on moist surfaces and in urine for several hours. - can be spread by

toilet seats, towels

is there a way that one can get food poisoning from food despite its having been heated in this way?

toxins are heat stable above temps that kill the BACT!

How are trypanosome diseases similar to malaria?

transmitted by insect vectors

Which of the following filariases can be controlled by thoroughly cooking pork and wild game?

trichinosis

Why are tapeworms flat?

use diffusion to get nutrients, need larger SA

microbial control:

wash, bleach, refrigerate, NOT MICROWAVE

Pickling is a type of food preservation utilizing

weak acids