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Bio23L Lab Final > Lab Final > Flashcards

Lab Final Flashcards

1
Q

How can infections in the urethra and bladder be detected

A

by obtaining a clean-catch sample of urine

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2
Q

What tests are used to characterize catalase-negative Gram-positive cocci?

A
  • Hemolysis test
  • Bile esculin test
  • PYR test
  • CAMP test
  • Antibiotic susceptibility test
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3
Q

Transduction

A

The addition of DNA to a bacterium via a prophage

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4
Q

MPN test: Does the presence of gas in a presumptive test mean that coliform bacteria are present?

A

No, a confirming test must be done

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5
Q

Streptolysin O

A

is oxygen liable and cannot perform hemolysis in the presence of oxygen

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6
Q

reservoir

A

a place where infectious agents can multiply

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7
Q

2 ml of food is added to 8 ml of water, what is the final dilution?

A

2:10 or 1:5

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8
Q

What are the characteristics of Staphylococcus sp.?

A
  • Gram-positive cocci in singles, pairs, tetrads or clusters
  • catalase positive
  • facultative anaerobes
  • most are oxidase negative
  • can grow in 6.5% NaCl
  • Most produce acid from glucose
  • Most are resistant to bacitracin
  • Hemolytic reactions vary by species
  • Key pathogen is S. aureus, known to be the causative of toxic shock syndrome and a variety of other infection
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9
Q

Antibiotic susceptibility

A

Antibiotic sensitivity or antibiotic susceptibility is the susceptibility of bacteria to antibiotics.

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10
Q

Streptokinase

A

prevents blood clots and disintegrates them

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11
Q

What are the symptoms of cystitis?

A

dysuria (frequent and painful urination) and pyuria (the presence of leukocytes and pus in the urine)

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12
Q

What is important to remember when performing a hemolysis test with Streptococci or Enterococci?

A

you must streak and stab the blood agar plate; a uniform lawn is made and stabs are made with the loop. Stabs allow bacteria to be introduced to an anaerobic, so you can better determine if the hemolysin is Streptolysin S or Streptolysin O

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13
Q

In the MPN assay the 95% confidence limits are ___________.

A

The upper and lower limits of bacteria that may be in a water sample

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14
Q

DNase

A

an enzyme that breaks down DNA

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15
Q

What are the characteristics of Enterococcus?

A
  • Formerly members of Streptococcus
  • Gram-positive cocci to ovoid cocci in singles, pairs or short chains
  • Catalase negative
  • Oxidase negative
  • Facultative anaerobes
  • Ferments to lactic acid without gas
  • Can grow in 6.5% NaCl
  • Can grow in bile esculin
  • Most are PYR positive
  • Most species are commensals or opportunistic pathogens
  • Key pathogen is Enterococcus faecalis
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16
Q
A
    • and - strand
  2. progametangia
  3. gametangia
  4. zygosporangium
  5. zygospores
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17
Q

How was the GFP protein put into the bacteria?

A

it was done with plasmid vectors; pGLO plasmids

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18
Q

What is the difference between Antiseptics and Disinfectants?

A

Antiseptics are used on living tissues, disinfectants are used on non-living surfaces; sometimes a chemical can be an antiseptic or disinfectant depending on the concentration of the chemical.

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19
Q

What is the arabinose promoter called

A

Pbad

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20
Q

What are the asexually produced spores of Rhizopus called?

A

Sporangiospores; they are produced in sporangia at the end of sporangiophores

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21
Q

Fibronectin-binding protein

A

an adhesin/binding protein that allows bacteria to attach to a host’s epithelial cells

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22
Q

Some members of Enterobacteriaceae are ____________ like E.coli which are normal microbiota in mammalian intestinal systems, others like Shigella sp. are always considered to be ____________ to humans

A
  • Commensals
  • True pathogen
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23
Q

When is it okay to use an intermediate antibiotic?

A

never

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24
Q

What happens if cystitis is not properly treated?

A
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25
Q

In the pGlo experiment what substance was used to make the E.coli’s membranes permeable to the plasmids?

A

CaCl2

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26
Q

Hyaluronidase

A

hydrolyzes hyaluronic acid in connective tissue

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27
Q

Fomites

A

objects or materials that are likely to carry infection, such as clothes, utensils, and furniture.

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28
Q

MPN: In the last set of 3 10 ml lactose tubes how much broth is removed and how much water is added?

A

0.1 of an ml is discarded to make 9.9 ml tubes and 0.1 ml of water source is added

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29
Q

E

A

Erythromycin

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30
Q

Staphylococci, Streptococci, and Enterococci are _________
_____________.

A
  • pyogenic
  • Gram-positive bacteria
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31
Q

1 ml of 1:10 dilution is added to 9 ml of water, then 1 ml of that solution is added to 99 ml of water, what is the final dilution?

A

1:10,000

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32
Q

CAMP test

A

This test can be performed on catalase-negative gram-positive cocci to differentiate the bacterium Streptococcus agalactiae from other bacteria. The CAMP test is a test to identify Group B β-streptococci based on their formation of a substance (CAMP factor) that enlarges the area of hemolysis formed by β-hemolysin from Staphylococcus aureus. It is frequently used to identify Group B Strep (Streptococcus agalactiae).

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33
Q

Sepsis

A

the growth of any microorganism

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34
Q

Streptolysin S

A

is stable in the presence of oxygen and can still perform hemolysis in an oxygenated environment

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35
Q

Describe the life cycle of Plasmodium vivax. What type of transmission is described?

A
  1. Transmission to host by mosquito in sporozoite form
  2. Schizogony of P. vivax occurs in liver of the host or RBCs (Schizonts); merozoites are produced by schizonts
  3. Merozoites released into bloodstream to infect red blood cells
  4. Merozotie enters ring stage in RBC (Trophozoite)
  5. Trophozoite grows becomes a schizont which divides, producing merozoites
  6. Merozoites lyse RBC
  7. Merozoites mature into gametocytes (sexually mature) and are ingested by mosquito vector or stay merozoites and infect other RBCs
  8. inside mosquito gametocytes unite to form a zygote
  9. Zygotes mature into sporozoites and are ready to be transmitted to another human

* this is an example of biological transmission

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36
Q

Bile esculin test

A

The bile esculin test is a selective and differential medium used to detect enterococci and certain types of streptococci. Bile inhibits the growth of some gram-positive bacteria. If bacteria grow and can hydrolyze esculin into esculetin and dextrose, the esculetin interacts with ferric citrate in the medium and forms a brown/black precipitate after incubation.

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37
Q

An infection of the urethra or urinary bladder

A

Urinary Tract Infection (UTI)

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38
Q

what is the range of CFUs that is statistically acceptable to use when determining the number of bacteria present in 1.0 g of a food sample?

A

30-300 CFUs

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39
Q

How do molds reproduce?

A

via sexual and asexual spores

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40
Q

MPN index per 100 ml refers to

A

the most likely amount of bacteria in a 100 ml sample of water

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41
Q

How do you calculate the amount of bacteria on a plate?

A

Number of colonies on plate x reciprocal of the dilution of sample = # bacteria/ml

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42
Q

What tests are typically used to characterize Gram-negative bacteria?

A
  • Indole test
  • Simmon’s citrate
  • MR test
  • Urease test
  • KIA test (Kligler Iron agar)
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43
Q

Novobiocin test

A

an antibiotic sensitivity test used to identify staphylococcus sp.

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44
Q
A

Schistosoma mansoni Lifecycle

  1. Schistosomula
  2. Adult Blood flukes (paired)
  3. Egg
  4. Miracidium
  5. Sporocyst
  6. Cercaria
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45
Q

Because Fungi are absorptive heterotrophs how do they obtain nutrients?

A

they secrete exoenzymes that digest nutrients outside the cells, nutrients are then absorbed by the fungus.

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46
Q

Intermediate host

A

host in which asexual reproduction takes place

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47
Q
A

Lac operon: an inducible operon which controls the gene expression of the enzymes needed to break down lactose in bacteria.

  1. RNA polymerase
  2. Operator
  3. Promoter
  4. Structural genes
  5. Regulatory gene
  6. Repressor protein
  7. mRNA
  8. Lactose
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48
Q

Hyphae can be __________

A

separate; walls separate adjacent cells, or nonseparate; walls are absent between adjacent cells

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49
Q

Platyhelminths

A

flat worms

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50
Q

A Streptococci bacterium which causes infection in newborns passing through the birth canal.

A

Streptococci agalactiae

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51
Q
A
  • Organism: Ascaris lumbricoides
  • Stages: egg, larvae, adult worm
  • Infective Stage: Embryonated egg
  • Reservoirs: Humans, soil, inanimate objects
  • Mode of Transmission: Fecal-oral route
  • Diseases: Ascariasis
  • Symptoms: may be asymptomatic, bloody sputum, cough, fever, abdominal discomfort
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52
Q

What is the primary way in which nosocomial infections spread?

A

Nurses, doctors, and other healthcare professionals fail to wash their hands properly or sterilize equipment used in physical examinations, patients may already be immunocompromised by disease or trauma and are more susceptible to infections

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53
Q

What Domain and kingdom do helminths belong to?

A

Eukarya and Animalia

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54
Q

What indicator was used in the epidemic simulation? what color indicated a positive for infection? What was the pH of the original infectious broth?

A

Phenol red was the pH indicator used in the epidemic simulation, a yellow color change indicated infection. The pH of the original infectious broth was acidic below 6.8.

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55
Q

Why is a lactose test performed?

A

The purpose of a lactose test is to determine whether a bacterium can ferment lactose or not. Bacteria that can ferment lactose will produce acidic end products, which will cause the pH indicator phenol red to turn yellow. In the case of the KIA test the combined acidic end products from glucose and lactose fermentation will cause the whole test tube to turn yellow indicating that the bacterium can ferment lactose.

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56
Q
A
  • Organism: Taenia sp.
  • Stages: Egg, cysticerci, adult tapeworm
  • Infective Stage: cysticerci
  • Reservoirs: Humans, pigs, contaminated food and water
  • Mode of Transmission: Vehicle-borne (undercooked beef and pork)
  • Diseases: Taeniasis, cysticercosis
  • Symptoms: may be asymptomatic, abdominal pain, loss of appetite, weight loss, upset stomach
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57
Q

VRE

A

Vancomycin-resistant enterococci (VRE) are a type of bacteria called enterococci that have developed resistance to many antibiotics, especially vancomycin. Enterococci bacteria live in our intestines and on our skin, usually without causing problems. But if they become resistant to antibiotics, they can cause serious infections, especially in people who are ill or weak. These infections can occur anywhere in the body. Some common sites include the intestines, the urinary tract, and wounds.

Vancomycin-resistant enterococci infections are treated with antibiotics, which are the types of medicines normally used to kill bacteria. VRE infections are more difficult to treat than other infections with enterococci, because fewer antibiotics can kill the bacteria.

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58
Q

Most fungi are Saprophytic, what does saprophytic mean?

A

Saprophytes are more generally plants, fungi, or micro-organisms that live on dead or decomposing matter.

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59
Q

NB

A

Novobiocin

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60
Q

Is S. epidermidis pathogenic?

A

It is capable of causing disease in humans and is frequently the cause of nosocomial infections

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61
Q

What Polysaccharide is found in a fungal cell wall?

A

Chitin

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62
Q

10 ml of food is added to 10 ml of water, what is the final dilution?

A

10:20 or 1:2

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63
Q

Animals are _________.

A

Ingestive Chemoheterotrophs

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64
Q

A plate with +pGLO bacteria with LB, ampicillin and arabinose should have__________.

A

Some colonies which are resistant to ampicillin and glow under UV light

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65
Q

MPN: In the first sets of 3 10 ml lactose tubes how much broth is removed and how much water is added?

A

No water is removed, but 10 ml of water is added to 10 ml of lactose broth

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66
Q

Plate count method

A

a way to approximate the number of microbes in a reservoir; serial dilutions are made and plates are inoculated with different dilution ratios. The number of cfus are counted in each dilution then the the concentration of bacteria will be calculated using the number of cfus and the dilution factor.

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67
Q

Bacteriocidal

A

Chemicals which kill bacteria

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68
Q

Gamma hemolysis

A

non-hemolysis; no change to medium. Staphylococcus, Streptococcus and Enterococcuse may be gamma hemolytic.

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69
Q

What happens when lactose/arabinose is not present?

A

The repressor protein is still attached to the operator and RNA polymerase cannot attach to the promoter and begin transcription of the structural genes

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70
Q

many streptococci cause disease but which is most virulent?

A

Streptococcus pyogenes

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71
Q

Prostatitis

A

Inflammation of the small walnut-shaped gland (prostate) that produces seminal fluid.

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72
Q

What is MRSA?

A

a strain of S. aureus which is resistant to methicillin and is coagulase positive

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73
Q

+pGLO

A

had the pGLO plasmid

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74
Q

What major diseases does Viridans Streptococci cause?

A
  • Subacute bacterial endocarditis
  • bacteremia
  • meningitis
  • gingivitis
  • abscesses
  • osteomyelitis
  • empyema
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75
Q

Food is a combination of __________.

A

reservoirs

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76
Q

What is the most common pathogen in the Staphylococcus genus?

A

Staphylococcus aureus

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77
Q

What cellular arrangement do Streptococci and Enterococci assume when grown in liquid broth?

A

a chain-like cell arrangement

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78
Q

Schizogony

A

asexual reproduction by multiple fission, found in some protozoa, especially parasitic sporozoans.

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79
Q

Hyaluronic acid capsules

A

Allows bacteria to avoid phagocytosis and hide its antigens

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80
Q

How does sexual reproduction occur in Rhizopus?

A

different mating types + and - strands respond to chemicals in the environment that are released by the opposite mating type , this causes the + and - strands to grow hyphae towards eachother. Specialized ends on these hyphae are called progametangia; progametangia make contact and they separate from the rest of the filiment and gametangia are formed. Gametangia fuse togther to form a zygosporangium. Gametoangia nuclei fuse to make a diploid zygote, after under going meiosis the nuclei become haploid, and haploid zygospores are formed. Zygospores are released at the end of the sporangiophore.

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81
Q

1 ml of food sample is added to 9 ml of water, what is the final dilution?

A

1:10

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82
Q

Coagulase

A

The enzyme coagulase allows bacteria to form clots from fibrin found in blood plasma. Organisms that produce coagulase can form protective barriers of fibrin around themselves, making themselves highly resistant to phagocytosis, other immune response, and some antimicrobial agents.

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83
Q

Why is a Simmon’s citrate test performed?

A

This test determines whether a bacterium can utilize citrate as its sole carbon source. If the bacteria can use citrate as a carbon source they will use ammonia salts in the medium; this will produce ammonia which will lower the pH of the media and cause the bromthymol blue in it to turn blue.

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84
Q

What are the classes of the phyla platyhelminths?

A
  • Turbellaria
  • Trematoda (human pathogens)
  • Cestoda (human pathogens)
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85
Q

How was the arabinose operon modified?

A

The araB, araA, and araD genes were replaced with the GFP gene, the bacteria can no longer digest arabinose, but the bacteria will glow in the presence of arabinose

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86
Q

What are the characteristics of bacteria in the family Enterobacteriaceae?

A
  • Gram negative
  • Facultative anaerobes
  • Oxidase negative
  • Acid production from glucose (with or without gas)
  • Most are catalase positive
  • Most reduce nitrate to nitrite
  • Peritrichous flagella if motile
  • bacilli or cocobacilli
  • most form greyish colonies
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87
Q

A Streptococci bacterium which is the number one cause of dental carries.

A

Streptococcus mutans

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88
Q

If the zone of inhibition for E.coli is 12mm for disinfectant A and 4mm for disinfectant B, which one is more effective? Explain.

A

Disinfectant B is more effective because it has a larger zone of inhibition than disinfectant A. A larger zone of inhibition indicates that the substance in the disk is more toxic to the bacteria and the bacteria are less likely to be resistant to it.

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89
Q

Why is it important to use a MacFarland 0.5 for Kirby-Bauer antibiotic testing?

A

The appropriate concentration of bacteria must be inoculated onto the agar plate so that that effect of the antibiotics can be accurately determined.

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90
Q

Why do different bacterial species respond differently to different antibiotics?

A

Different species of bacteria can respond differently to the same antibiotic because each species has different DNA coding for different traits, these traits can make a bacterium vulnerable or impervious to an antibiotic’s mechanism of action.

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91
Q

What types of bacteria would be on your hands after washing them?

A

your normal microbiota

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92
Q
A
  • Organism: Enterobius vermicularis
  • Stages: egg, larvae, adult worm
  • Infective Stage: Embryonated egg
  • Reservoirs: Humans
  • Mode of Transmission: Fecal-oral route
  • Diseases: Enterobiasis (pinworm infection)
  • Symptoms: itchy anal region
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93
Q

Cystitis

A

inflammation of the urinary bladder

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94
Q

What are the virulence factors of Salmonella and what are some illnesses it can cause?

A
  • Fimbriae that allow adherence to intestinal mucosa
  • Ability to transverse intestinal mucosa
  • Enterotoxins that cause gastroenteritis
  • Salmonellosis
  • gastroenteritis
  • typhoid fever
  • non-typhoidal bacteremia
  • Carrier state
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95
Q

A plate with +pGLO bacteria with LB and ampicillin should have__________.

A

some growth of amp resistant bacteria should not be a lawn

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96
Q

Cestodes

A

often called tape worms

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97
Q

Definitive host

A

host in which sexual reproduction takes place

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98
Q

Why is a glucose gas test performed?

A

This test determines if a bacterium can produce gas while fermenting glucose. When bacteria produce gas while fermenting glucose it displaces broth in a durham tube or breaks up the agar in a KIA test to form gas bubbles or pockets.

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99
Q

EMB plates

A

Eosin Methylene Blue agar

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100
Q

Enterococci are the most common cause of __________ infections, especially when medical devices and prolonged antibiotic use are involved.

A

Nosocomial

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101
Q

Fungal diseases in humans are often ____________.

A

oppertunistic

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102
Q

Pandemic

A

a global or national epidemic

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103
Q

What is the protein that causes the transformed bacteria in the pGlo experiment to fluoresce green under UV light?

A

GFP (Green Fluorescent Protein)

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104
Q

MacFarland 0.5

A

In microbiology, McFarland standards are used as a reference to adjust the turbidity of bacterial suspensions so that the number of bacteria will be within a given range to standardize microbial testing. An example of such testing is antibiotic susceptibility testing by measurement of minimum inhibitory concentration which is routinely used in medical microbiology and research. If a suspension used is too heavy or too dilute, an erroneous result (either falsely resistant or falsely susceptible) for any given anti microbial agent could occur.

Original McFarland standards were mixing specified amounts of barium chloride and sulfuric acid together. Mixing the two compounds forms a barium sulfate precipitate, which causes turbidity in the solution. A 0.5 McFarland standard is prepared by mixing 0.05 mL of 1.175% barium chloride dihydrate (BaCl2•2H2O), with 9.95 mL of 1% sulfuric acid (H2SO4).

Now there are McFarland standards prepared from suspensions of latex particles, which lengthens the shelf life and stability of the suspensions. The standard can be compared visually to a suspension of bacteria in sterile saline or nutrient broth. If the bacterial suspension is too turbid, it can be diluted with more diluent. If the suspension is not turbid enough, more bacteria can be added.

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105
Q

Why is water tested for coliforms?

A

to determine whether or not a water source has been contaminated with sewage since coliforms are easy to grow; their presence indicates that a water source has been contaminated with sewage and there may be pathogens in the contaminated water

106
Q

Enterococcus species is _______ tolerant.

A

salt

107
Q

How can bacteria infect the urinary system?

A

bacteria can enter and colonize the urethra and make their way up into the urinary bladder if left undetected and untreated bacteria can colonize the ureters and the kidneys.

108
Q

Staphylococci, Streptococci, and Enterococci are commonly found where?

A

epithelial surfaces such as skin and mucous membranes

109
Q

What is LB broth?

A

Luria-Bertani broth

110
Q

Calculate the number of CFUs per ml of urine if a 10 microliter loop is used to inoculate CNA and EMB agar, resulting in 32 colonies for CNA and 47 colonies for EMB.

A

CNA: 3200 CFU/ml or 3.2 x 103 CFU/ml

EMB: 4700 CFU/ml or 4.7 x 103 CFU/ml

111
Q

Lancefield grouping

A

Lancefield grouping is a method of grouping catalase-negative, coagulase-negative bacteria based on the carbohydrate composition of bacterial antigens found on their cell walls.

112
Q

What assay is used to routinely test water sources for coliform bacteria?

A

Most Probable Number Assay (MPN)

113
Q

What is an instance when a commensal can cause disease and what would this type of disease be called?

A

If a commensal is introduced to another part of the body it where it is not normally found it could cause an opportunistic infection

114
Q

What are the 4 natural reservoirs for human infections?

A
  1. soil
  2. animals
  3. water
  4. human
115
Q

before the mid 1980s if an individual had bacterial counts of >100,000 CFU/ml they were diagnosed with a UTI

A
116
Q
A
117
Q

What type of microbes are likely to be present on unwashed hands?

A

transient bacteria that may be pathogenic

118
Q

Streptolysin O

A

Non-oxygen stable hemolysin; allows bacteria to destroy red blood cells to obtain iron.

119
Q

Lipoteichoic acid

A

allows bacteria to adhere to the epithelial cells of hosts

120
Q
A
  • Organism: Taenia sp.
  • Eukarya Animalia Platyhelminthes Cestoda Taenia solium
  1. Mature proglottids
  2. Gravid proglottids
  3. Scolex
  4. Neck
121
Q

TE

A

Tetracycline

122
Q

MHA prevents the ______ of some antibiotics

A

inhibition

123
Q

coliforms

A

They are defined as rod-shaped Gram-negative non-spore forming, facultative anaerobes and motile or non-motile bacteria which can ferment lactose with the production of acid and gas when incubated at 35–37°C.[1] Coliforms can be found in the aquatic environment, in soil and on vegetation; they are universally present in large numbers in the feces of warm-blooded animals.

124
Q

What is the source of the GFP protein in the pGLO lab?

A

a bioluminescent Jellyfish; Aequorea victoria

125
Q

Small isolated colonies within the zone of inhibition

A

Satellite colonies; these bacteria are resistant to the drug , this would mean the drug is not suitable for this bacteria

126
Q

-pGLO

A

does not have the pGLO plasmid

127
Q

What is the purpose of a glucose fermentation test?

A

This test determines if a bacterium can ferment glucose. When the bacterium ferments glucose acidic end products are made this lowers the pH of the medium, phenol red will then turn yellow

128
Q

How do yeasts reproduce?

A

Budding

129
Q

The MPN test can determine how much coliform bacteria are in ________water sample

A

100 ml

130
Q

Why are fungal infections hard to treat?

A

because fungi are eukaryotic, like the cells that make up our bodies so drugs that are harmful to fungi can also be harmful to us.

131
Q

L-UTI

A

lower urinary tract infection

132
Q

What antibiotic is tested for to differentiate Beta-hemolytic group A streptococci from other Beta-hemolytic streptococci?

A

Bacitracin

133
Q

flukes can attach to hosts by 2 ________

A

suckers, an oral and ventral sucker

134
Q

How are the lac operon and arabinose operon similar?

A

They both require an inducer to deactivate the repressor protein on their operators

135
Q

What are the two phyla of helminths?

A

Platyhelminths and Nematoda

136
Q

Conjugation

A

the exchange of plasmids through bacterial sex

137
Q

How can bacteria acquire new genetic information?

A
  • transformation
  • conjugation
  • transduction
138
Q

Acute Urethral syndrome

A

Includes dysuria and pyuria. Defined as more thank 8 white blood cells per cubic millimeter of uncentrifuged urine

139
Q

Why is an Indole test performed?

A

to determine id a bacterium can make tryptophanase when tryptophan is hydrolyzed by tryptophanase indole is produced, if indole is produced Kovac’s reagent interacts with indole to form a pink ring on top of the broth in the test tube (positive).

140
Q
A
  • Organism: Plasmodium sp.
  • Stages: Trophozoites (ring stage), sporozoites, schizonts, merozoites, gametocytes, zygotes, oocytes
  • Infective Stage: Sporozoite
  • Reservoirs: Humans and mosquitos
  • Mode of Transmission: Vector-borne
  • Diseases: Malaria
  • Symptoms: Chills, high fever, profuse sweating, headache, nausea, vomiting, diarrhea, anemia, muscle pain, convulsions, coma, bloody stools
141
Q

hyphae

A

one of the threadlike elements of the mycelium.

142
Q

Commensalism

A

Commensalism is a relationship between two organisms where one receives a benefit or benefits from the other and the other is not affected by it. In other words, one is benefited and the other is neither benefited nor harmed.

143
Q

the arabinose operon is an ____________.

A

Inducible operon; arabinose (inducer) is needed to deactivate the repressor protein and allow RNA polymerase to make mRNA from the structural genes

144
Q

What infectious route may a pathogen in water or food take?

A

Fecal-oral routes

145
Q

What major diseases are caused by Streptococcus pyogenes?

A
  • bacterial pharyngitis
  • impetigo
  • erysipelas
  • cellulitis
  • scarlet fever
  • necrotizing fasciitis
  • Streptococcal toxic shock syndrome
  • Rheumatic fever
  • Acute glomerulonephritis
146
Q

How is the effectiveness of an antibiotic tested?

A

The agar diffusion test (Kirby–Bauer antibiotic testing, KB testing, or disc diffusionantibiotic sensitivity testing) is a test of the antibiotic sensitivity of bacteria. It uses antibiotic-impregnated wafers to test the extent to which bacteria are affected by those antibiotics.

147
Q

Fungi are _____________.

A

absorptive chemoheterotrophs

148
Q

Urethritis

A

inflammation of urethra

149
Q
A

This method of urine culturing is called the semiquantitative streak method, this method provides a rapid way to estimate the CFU/ml of urine without using serial dilutions. Disposable inoculating loops are calibrated to 10 ul are used to transfer 1 ul of urine sample to plated media. The streak method uses a single streak down the center of the plate, followed by a rotation of the plate without flaming . The second streak is performed by dragging the loop in a zig-zag pattern across the first streak. Following incubation, the number of CFUs/ml is calculated by multiplying the CFUs by the loop volume.

150
Q

Plants are ________.

A

photoautotrophs

151
Q

EMB

A

Eosin methylene blue agar (EMB) is a selective and differential medium toxic to gram positives and identifies lactose fermenters (colonies appear purple and pink) and E. coli appear metallic green

152
Q

PYR test

A

Some streptococci and enterococci can produce L-pyrrolidonyl arylamidase , which hydrolyzes pyroglutamyl- Beta-napthylamideto produceL-pyrrolidoneandBeta-napthylamine.To perform this test, bacteria are inoculated onto plated media (usually sheep’s blood agar). After incubation bacteria and water is placed on a PYR card containing a disk withpyroglutamyl- Beta- napthylamide. After several minutes PYR reagent is added to the card, no color change, yellow or orange is negative and cherry red is positive. This test is not performed on Staphylococcus.

153
Q

Explain what is happening to the concentration of a substance as you move further from the disk saturated with that substance.

A

The closer to the disk the higher the concentration of antimicrobial substance, the molecules diffuse from the disk into the surrounding media, the farther from the disk the less molecules.

154
Q

If both CNA and EMB plates had substantial growth what can be interpreted from that and what kind of antibiotic could be used to treat this possible infection?

A

Over 102 bacteria on both plates would indicate a mixed infection and the best antibiotic for a mixed infection would be a broad spectrum antibiotic.

155
Q
A
  • Organism: Schistosoma sp.
  • Stages: Miracidia, sporocysts, cercariae, schistosomulae
  • Infective Stage: cercariae
  • Reservoirs: Humans, dogs, cats, rodents, pigs, horses, goats
  • Mode of Transmission: Indirect contact (water)
  • Diseases: Schistomiasis, katayama fever, symmers pipe stem periportal fibrosis, portal hypertension, embolic egg granulomas
  • Symptoms: rash/itchy skin, fever, chills, cough, muscle aches
156
Q
A
  • Organism: Entamoeba histolytica (Trophozoite and Cyst)
  • Stages: Cyst, Trophozoite
  • Infective Stage: Cyst
  • Reservoirs: Water, soil, food, and humans
  • Mode of Transmission: Fecal-oral route
  • Diseases: amoebiasis, amoebic dysentery, amoebic liver abscess
  • Symptoms: Fulminating dysentery, bloody diarrhea, weight loss, fatigue, abdominal pain, can be asymptomatic
157
Q

O

A

Optochin- an antibiotic used in sensitivity testing for Streptococcus and Enterococcus

158
Q

What is the purpose of an MR test

A

A methyl red test determines whether a bacterium can produce multiple acids when fermenting a carbohydrate. Methyl red is added to a test tube that has growth in it, if multiple acids are present the pH will be very low and the broth will turn red when methyl red is added to it.

159
Q

Where is the Kirby-Bauer method of antibiotic testing most often used?

A

In medical microbiology labs; the agar plates used are often bigger than average, usually 30-40 antibiotics are tested at one time.

160
Q

Mycelium

A

the vegetative part of a fungus, consisting of a network of fine white filaments (hyphae).

161
Q

Streptolysin S

A

Oxygen stable hemolysin; allows bacteria to destroy red blood cells to obtain iron.

162
Q

What type of protist is the only kind of protist that can cause infections in humans?

A

animal like protists

163
Q
A
164
Q

What are the characteristics of Streptococci?

A
  • Gram-positive cocci to ovoid cocci in singles, pairs or short chains
  • Catalase negative
  • Oxidase negative
  • Facultatively anaerobic
  • Nutritionally fastidious
  • Some are capnophilic
  • Many produce hemolysins which partially or completely destroy RBCs, some do not have hemolysins
  • Key pathogens are S. pyogenes and S. pneumoniae
165
Q

List the major diseases caused by S. aureus.

A
  • MRSA
  • Toxic Shock syndrome
  • Staphylococcal food poisoning
166
Q

Some antibiotics have a larger molecular size or are less soluble and have different diffusion rates, so how is antibiotic effectiveness determined?

A

determination of the most effective antibiotics is done by comparing the zones of inhibition of each antibiotic for specific organisms, the zone sizes are then compared to published values for each antibiotic, nd the results are interpreted as susceptible, resistant or intermediate

167
Q

Calculate the number of CFU per gram of food if the plate is labled 1:1,000 and has 89 colonies

A

89,000 or 8.9 x 104 bacteria

168
Q

What is an important feature of Enterococci?

A

they are resistant to commonly used antibiotics

169
Q

Trematodes

A

often called flukes

170
Q

Nosocomial infections can never be fully ___________, and more than 40,000 people die from HAIs each year

A

prevented

171
Q

What are some of the infections Enterococci can cause?

A
  • UTI
  • endocarditis
  • bacteremia (systemic infection)
172
Q

The spread of microbes via __________ or __________ is one of the most important means of disease transmission.

A
173
Q

BA

A

Bacitracin- an antibiotic used in sensitivity testing for Streptococcus and Enterococcus

174
Q

what does dimorphic mean when referring to fungi?

A

The fungi is able to exist as a mold and a yeast

175
Q

What is the purpose of a Kligler’s Iron agar test?

A

This test determines whether a bacterium can produce hydrogen sulfide. A positive test result is indicated by black precipitate on the medium; the black precipitate is caused by the combination of H2 S produced by the bacteria and the sodium thiosulfate and ferrous sulfate in the test medium.

176
Q

Intermediate antibiotic susceptibility

A

Bacteria are affected by the antibiotic but not affected to the point where they are completely killed or stopped from growing.

177
Q

Schizont

A

a cell that divides by schizogony to form daughter cells.

178
Q

Hemolysis test

A

tests for a bacteria’s ability to produce hemolysins which cause hemolysis of red blood cells. Sheep blood agar plates are used (BAP) as a test medium and pure cultures are streaked across the surface. This test allows for the differentiation of the types of hemolysis.

179
Q

Selective and Differential media

A

Selective and differential media are used to isolate or identify particular organisms

Examples of selective media include:

  • Eosin methylene blue contains dyes that are toxic for Gram-positive bacteria. …
  • YM (yeast extract, malt extract agar) has a low pH, deterring bacterial growth.
  • MacConkey agar is for Gram-negative bacteria.
  • Hektoen enteric agar is selective for Gram-negative bacteria.
  • Columbia CNA agar has chemicals in it that are toxic to Gram-negative bacteria
180
Q

Erythrogenic toxin

A

exotoxins which cause inflammation

181
Q

Alpha hemolysis

A

The partial destruction of RBCs and hemoglobin; medium turns green. Staphylococci cannot perform alpha hemolysis, only certain streptococcus and enterococcus species can.

182
Q

Transformation

A

transformation is the genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material (exogenous DNA) from its surroundings through the cell membrane(s).

183
Q

Do all disinfectants and antibiotics work equally the same against all bacteria? Explain.

A

No, because different antiseptics and disinfectants have different mechanisms of action; each targets different parts or physiological processes of a bacterium. Because different genera, species, and subspecies have different traits, they might not all have the same vulnerabilities and will not respond the same to a certain antiseptic/disinfectant.

184
Q

M-Protein

A

helps bacteria to resist phagocytosis

185
Q

Bacteriostatic

A

Chemicals which inhibit the growth of bacteria

186
Q

MSA

A

Mannitol salt agar- tests for mannitol fermentation and salt tolerance; this is a selective and differential medium. 7.5% Salt is the selective ingredient and mannitol is the differential ingredient. Phenol red is also added as a pH indicator; yellow is a positive result.

187
Q

AMC

A

Amoxicillin

188
Q
A
  • Organism: Giardia lamblia (Trophozoite and Cyst)
  • Stages: Cyst, Trophozoite
  • Infective Stage: Cyst
  • Reservoirs: Water, soil, animals, and humans
  • Mode of Transmission: Fecal-Oral route
  • Diseases: Giardiasis
  • Symptoms: Diarrhea, gas, greasy stool, stomach cramps, upset stomach, nausea, dehydration, weight loss
189
Q
A
  • Organism: Balantidium coli (Cyst and Trophozoite)
  • Stages: Cyst, Trophozoite
  • Infective Stage: Cyst
  • Reservoirs: Water, Food, Pigs
  • Mode of Transmission: Fecal-oral route
  • Diseases: Balantidiasis
  • Symptoms: May be asymptomatic, diarrhea, dysentery, abdominal pain, weight loss, nausea and vomiting
190
Q

MAC

A

MacConkey Agar Is a selective and differential medium which is selective for gram-negative bacteria , it also differentiates lactose fermenters from non-lactose fermenters (lactose fermenters appear pink)

191
Q

____________ is important cause of lung infections leading to pneumonia, meningitis and is the number one cause of ear infections in children.

A

Streptococci pneumoniae

192
Q

What antibiotic is used for sensitivity testing to determine whether a bacterium is Streptococcus pneumoniae or another alpha-hemolytic streptococci?

A

Optochin

193
Q

BAP

A

blood agar plate

194
Q

What is special about the pGLO plasmid?

A

It has been genetically engineered to encode the GF protein and the bla gene for ampicillin resistance. pGLO is also regulated by a modified arabinose operon, this controls the expression for GFP.

195
Q

What are the virulence factors of Shigella and what are some illnesses it can cause?

A
  • Acid tolerance
  • Effector proteins allow shigella to adhere to and transverse intestinal mucosa
  • Enterotoxins; Shiga toxins
  • Shigella can utiliz eukaryotic cell’s actin
  • Can evade and kill macrophages
  • Shigellosis
196
Q

TNTC

A

too numerous to count

197
Q

Why must Mueller-Hinton agar plates be uniform in thickness?

A

so the diffusion of antibiotics is equal on all plates

198
Q

Where is S.aureus usually isolated from?

A

nasal passages

199
Q

Explain why the number of infections may not double after the first 2-3 interactions.

A

After the first 2-3 interactions the number of “infected” increased, this increases the likelihood of an interaction between 2 individuals who are already infected; this would result in no new infections.

200
Q

Antibiotic susceptibility test

A

For the identification of Streptococci or Enterococci antibiotic sensitivity or resistance is commonly determined. When preparing the hemolysis test , one disk of each antibiotic is applied to the bacterial lawn. After incubation, the zone of inhibition is measured and sensitivity and resistance is determined using a chart of measurements and results

201
Q

How could you use a 1:10,000 dilution to make a 1:100,000 dilution?

A

add 1 part of the 1:10,000 solution to 9 ml of water or take out 0.1 ml of the solution; this adds a zero to the dilution factor

202
Q

where does the repressor protein come from?

A

A structural gene somewhere else in the DNA which is transcripted and translated into a protein

203
Q

What are the virulence factors associated with the

Streptococcus species?

A
  1. M-protein
  2. Fibronectin-binding protein
  3. Lipoteichoic acid
  4. Hyaluronic acid capsule
  5. Streptolysin O
  6. Streptolysin S
  7. DNase
  8. Streptokinase
  9. Hyaluronidase
  10. Erythrogenic toxin
204
Q

What major diseases are caused by Streptococcus pneumoniae?

A
  • pneumonia
  • sinititus
  • otitis media
  • bacteremia
  • meningitis
205
Q

Mueller-Hinton agar

A

Müller-Hinton agar is a microbiological growth medium that is commonly used for antibiotic susceptibility testing.It has a few properties that make it excellent for antibiotic use. First of all, it is a non-selective, non-differential medium. This means that almost all organisms plated on here will grow. Additionally, it contains starch. Starch is known to absorb toxins released from bacteria, so that they cannot interfere with the antibiotics. Second, it is a loose agar. This allows for better diffusion of the antibiotics than most other plates. A better diffusion leads to a truer zone of inhibition.

206
Q

What bacteria was used for the pGLO experiment?

A

Non-ampicillin resistant E. coli without arabinose operons

207
Q

What diseases does S. pyogenes cause?

A
  • scarlet fever
  • strep throat
  • rheumatic fever
  • impetigo
208
Q

SXT

A

SXT- an antibiotic used in sensitivity testing for Streptococcus and Enterococcus

209
Q

Bacteriuria

A

Bacteria in the urine

210
Q

The araC in the arabinose operon is the ____________.

A

operator

211
Q

VA

A

Vancomycin

212
Q

A plate with -pGLO bacteria with LB only should have__________.

A

E.coli growth

213
Q

What are the life cycle stages of Schistosoma mansoni?

A
  1. Adult blood fluke in human host
  2. Eggs in feces
  3. Miracidium infects snail
  4. Miracidium becomes sporocyst in snail (asexual phase takes place in snail)
  5. Sporocysts divide and proliferate each develops into cercaria
  6. Cercariae leave the snail and enter water
  7. Cercariae find human and enter through hair follicle
  8. Cercariae lose their tails and become schistosomulum and finds a vein
  9. schistosomulum follow current to the heart and to the arteries into the liver
  10. schistosomula mature and reproduce in the hepatic veins
214
Q

What are the 3 genera most responsible for gram-positive infections?

A
  • Staphylococcus
  • Streptococcus
  • Enterococcus
215
Q

Where do Enterococci reside?

A

in the GI tract

216
Q

Today a patient will be diagnosed with a UTI if the count is __________.

A

<10,000/ ml, depending on the species of bacteria and patient history , if a urine sample from a female patient displaying symptoms of cystitis contained more than 100 CFU/ ml urine of potential pathogens, a positive UTI is confirmed.

217
Q

S

A

Streptomycin

218
Q
A
  1. Sporangium
  2. Sporangiophore
  3. Stolon
  4. Rhizoid

*This photo depicts the asexual reproduction of Zygomycota Rhizopus

219
Q

MPN: In the second set of 3 10 ml lactose tubes how much broth is removed and how much water is added?

A

one ml is discarded from each tube to make the 9 ml tubes, and 1 ml of water sample is added

220
Q

How is the presumptive MPN test done?

A

3 sets of 10 ml lactose broth tubes are used , after incubation the number of gas positive tubes per series is recorded as a 3 digit number, the number is located on a table that provides the MPN/100 ml of water

221
Q

Epidemic

A

a widespread occurrence of an infectious disease in a community at a particular time.

222
Q

What is the purpose of a urease test?

A

this test is used to determine if a bacterium can produce urease to hydrolyze urea. A positive test result will be red/fuchsia; this is because the disk containing urea added to the broth also contains phenol red. When bacteria hydrolyze urea basic products are made which lowers the pH of the medium and causes it to turn red.

223
Q

Transformation solution

A

CaCl2

224
Q

Why are the bacteria heat shocked?

A

to moves the plasmids through the cell wall and plasma membrane

225
Q

What are hemolysins produced by streptococci called? What types are there?

A
  • Streptolysins
  • Streptolysin O
  • Streptolysin S
226
Q

Streptococcus species is not ___________ tolerant

A

salt

227
Q

Antibiotic resistance

A

Antibiotic resistance is the ability of a microorganism to withstand the effects of an antibiotic. It is a specific type of drug resistance. Antibiotic resistance evolves naturally via natural selection through random mutation, but it could also be engineered by applying an evolutionary stress on a population.

228
Q

Phylum Nemotoda

A

Phylum nemotoda includes roundworms, roundworms have a pointed posterior end and a smooth body

229
Q

Any zone of clearing around an SXT or Bacitracin disk among the ____________ ________is considered susceptibility.

A

Beta-hemolytic Streptococci

230
Q

Explain why the same bacterial species isolated from 2 different patients might have different responses to the same antibiotic using the Kirby-Bauer method.

A

One of the cultures of bacteria may possess a mutated gene which allows them to withstand an antibiotic that it may have been vulnerable to in the past.

231
Q

Beta hemolysis

A

Complete destruction of RBC and hemoglobin; agar appears clear; Staphylococci, Streptococci and Enterococci may be able to perfom Beta hemolysis

232
Q

CIP

A

Ciprofloxacin

233
Q

broad spectrum antibiotics vs. narrow spectrum antibiotics

A

The term broad-spectrum antibiotic refers to an antibiotic that acts against a wide range of disease-causing bacteria. A broad-spectrum antibiotic acts against both Gram-positive and Gram-negative bacteria, in contrast to a narrow-spectrum antibiotic, which is effective against specific families of bacteria.

234
Q

What is the average bacterial count per gram of food, plate 1, 1: 89 colonies on 1:1,000, plate 2, 32 colonies on 1:10,000 plate and 9 colonies on 1:100,000 plate?

A

(32) (10,000) = 320,000
(9) (100,000) = 900,000
(89) (1,000) = 89,000

Add all these togther and divide by 3

= 436,333 or 4.3 x 105 bacteria per ml of food

235
Q

What is the cut off rate for UTI infection?

A

102

236
Q

6.5% salt tolerance tests

A

salt is added to a standard medium called Tryptic soy broth, resulting in a final salt concentration of 6.5%. Staphylococci and Enterococci , but not other genera can thrive in a high salt environment.

237
Q

Coagulase test

A

a test used to detect coagulase, if culture is positive plasma will coagulate.

238
Q

How does hemolysis happen?

A

bacterial toxins called hemolysins destroy RBCs and hemoglobin, resulting in the release of iron from host cells for use by bacteria.

239
Q

How do protozoa move around?

A
  • psuedopodia
  • cillia
  • flagella
240
Q

If the modified E.coli are put in media that contains ampicilin and no arabinose will they grow and glow?

A

The bacteria will grow because they are resistant to ampicillin but they will not glow because arabinose is not present.

241
Q

How is a cell phone an example of a fomite?

A

A cell phone can be considered a fomite because it can carry germs that are easily spread to others, especially when health care workers use them or set them down in patient care areas with out washing their hands.

242
Q

Why is it important to give the correct antibiotic and the correct amount of antibiotics to a patient?

A

overuse or misuse can lead to antibiotic resistance, bacteria evolve mechanisms which allow them to survive and reproduce in the presence of an antibiotic

243
Q

Presumptive MPN tests are performed in _____________.

A

10 mls of lactose broth with inverted durham tubes to trap gas

244
Q

5 ml of food is added to 5 ml of water, what is the final dilution?

A

5:10 or 1:2

245
Q

bacteria in ________ usually cause UTIs but not always

A

feces

246
Q

A plate with -pGLO bacteria with LB and ampicillin should have__________.

A

No growth

247
Q

What are the virulence factors of Yersinia and what are some illnesses it can cause?

A
  • Produces invasive proteins; Ail, Yersinia adhesion A and invasins
  • Produces enterotoxins
  • Antigens on surface make bacteria resistant to opsonization and phagocytosis
  • Can utilize siderophores from other bacteria
  • enterocolitis, acute diarrhea, terminal ileitis, mesenteric lymphadenitis, and pseudoappendicitis but, if it spreads systemically, can also result in fatal sepsis.
248
Q

Selective-differential agars

A

these agars contain 2 or more ingredients to determine the bacterial physiology for 2 traits

249
Q

When testing a reservoir for bacteria it is important to perform_______________ due to high concentrations of bacteria

A

serial dilutions

250
Q

What major diseases are caused by Streptococcus agalactiae ?

A
  • pneumonia
  • meningitis in newborns
  • bacteremia in newborns
  • endometriosis in postpartum/abortion
  • wound infections in postpartum/abortion
251
Q

Cervicitis

A

inflammation of the cervix.

252
Q

-pGLO is supposed to be the __________.

A

control, to make sure the bacteria do not already have ampicillin resistant or fluorescing genes, or they are not already dead

253
Q

PB

A

Polymixin B

254
Q

What 2 forms do fungi come in?

A
  • Yeast (unicellular)
  • Mold (filamentous hyphae)
255
Q

Why are bacteria plated on media with and without ampicillin?

A

to select for transformed E.coli from non-transformed E.coli

256
Q

What are the steps to an MPN test?

A
  1. Presumptive test; involves growing bacteria in lactose and checking Durham for gas bubbles
  2. Confirming test; involves growing the bacteria from the presumptive test on EMB agar
257
Q
A
  • Organism: Trichomonas vaginalis (Trophozoite)
  • Stages: Trophozoite
  • Infective Stage: Trophozoite
  • Reservoirs: Humans
  • Mode of Transmission: Direct Contact (sexually transmitted)
  • Diseases: Trichomoniasis
  • Symptoms: May be asymptomatic, soreness and itching of the foreskin and vagina, Change in discharge (Thick or thin, frothy, yellow, white, unpleasant odor, etc.), pain when passing urine
258
Q

U-UTI

A

upper urinary tract infection

259
Q

Why is the production of urine a sterile process?

A

because bacteria cannot pass through the filtration membrane within the nephrons of the kidney.

260
Q

What is the phylum of Rhizopus?

A

Zygomycota

Bio23L Lab Final (1 decks)

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