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PID Exams > Bacterial Physiology, Human Disease, and Antibiotics > Flashcards

Bacterial Physiology, Human Disease, and Antibiotics Flashcards

1
Q

The patient In case 5 was an 18 year old. How would that be different today?

A

Majority of patients with menstrual TSS will be in the 11-13 y.o. range

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2
Q

What were the major presenting symptoms of the patient in case 5? (5)

A 
Vomiting 
Diarrhea 
Progressively Increasing fever 
Dizziness (hypotension) 
Macular erythroderma on abdomen and face
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3
Q

By 13 y.o. 80% of people will have antibodies to TSST1 and 20% won’t. Who is suceptible to the menstrual TSS, people with or without the antibody? Is there a way to help these people?

A

People without the antibody developed

IVIG when infected, or monthly IM injections of antigen

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4
Q

Why do tampons make women more succeptible to menstrual TSS?

A

The vagina is usually anaerobic, tampons trap oxygen, and the TSS1 toxin requires oxygen to be made

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5
Q

What is the significance of the vaginal yellow discharge in case 5?

A

Indicates that the colonizing bacteria was likely staph aureus

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6
Q

Menstrual TSS is associated with what 5 cardinal signs?

A 
Fever (Over 102)
Hypotension (less than 90/X)
Red rash (resembles sunburn)
Peeling skin (palms and soles)
Abnormal multiorgan changes (e.g. liver, platelets, mucous membranes)
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7
Q

What were the 2 drugs used to treat the patient in case 5? What 2 drugs would be used currently?

A

Nafcillin and Clindamyacin

Now, Use Vanco and Rifampin

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8
Q

What were the 2 candidate diagnoses in case 5?

A

Staphylococcus aureus toxic shock syndrome (TSS)

Group A streptococcal (Streptococcus pyogenes) TSS

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9
Q

Regarding the lab results, what chemistry values were elevated in case 5? What was low?

A

ALT AST CPK Creatinine BUN

Hypocalcemia

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10
Q

What was the infecting organism in case 5 that caused the menstrual TSS?

A

MSSA staph aureus producing superantigen TSS1

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11
Q

What is the significance of a left shift of WBCs?

A

Shows that the bone marrow was producing new WBCs, and some immature cells were being pushed out

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12
Q

What are the 2 organisms that can cause menstrual TSS? What is a major distinction between the 2?

A

Staph aureus and strep pyogenes (group A strep)
Staph A menstrual TSS will show staph limited to the throat and vagina, while Strep will most likely invade the bloodstream

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13
Q

What are band neutrophils and when would you expect to see them elevated?

A

Immature neutrophils, elevated during infection

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14
Q

What are some CNS findings associated with menstrual TSS?

A

Confusion and combativeness, without any focal neurological findings

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15
Q

Regarding drug treatment, what does it mean that the cultured organisms was MSSA? What is the antibiotic of choice for staphyloccocal TSS?

A

You can treat with penicillins and cephalosporins

Clindamycin

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16
Q

Why is renal failure especially bad in menstrual TSS?

A

Because the toxin TSST-1 is cleared by the kidneys

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17
Q

Why is clindamycin a good drug for the treatment of TSS?

A

Clindamycin is a protein synthesis inhibitor, and can prevent the manufacture of toxin even at concentrations below its antimicrobial range

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18
Q

While removal of The tampon (and trapped O2) helped in this case of menstrual TSS, in what case of menstrual TSS would removing the tampon not have helped?

A

If the causative agent was streptococcus pyogenes (group A strep), it would not have helped. Strep is an aerotolerant anaerobe

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19
Q

Regarding bacterial growth, what is the lag phase? log phase? stationary phase? Death phase?

A

Lag - enzymes being made to prepare for growth
Log - Exponential growth phase
Stationary - Nutrients used up, no more growth
Death - Bacteria are dying because of their toxic waste

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20
Q

What are The 2 significant types of bacteria regarding the death phase and how are they different?

A

Obligate fermenters die fast (hours) due to the presence of ROS, acid and H2O2 in the medium
Aerobes / oxidative bacteria can live for longer because of their metabolic enzymes

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21
Q

What phase of bacterial growth is associated with toxin production? How does this happen?

A

The post exponential phase, bacteria signal a quorum are present, initiating the production of exotoxin

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22
Q

Where is the lag phase longer, in people or in culture media?

A

In media, people have defense systems bacteria need to over come

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23
Q

What is an obligate aerobe? What enzymes does it have? What is the significance of these enzymes? What are the 2 examples provided?

A

Requires O2 to grow
SOD and catalase - convert superoxide amd acid eventually to water and oxygen
Bacillus and mycobacterium

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24
Q

What is a facultative anaerobe? What 2 enzymes do they have? What are the 2 examples provided?

A

Can grow in the presence (oxidative) or absence (fermentative) of oxygen
SOD and catalase
Staphylococcus and Escherichia

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25
Q

What is an aerotolerant anaerobe? What enzyme(s) do they have? What is the example provided?

A

Can grow in the presence of O2, but will still ferment
SOD (no catalase)
Streptococcus

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26
Q

What is an obligate anaerobe? What are the 2 examples provided?

A

Can only grow in the absence of O2
No catalase or SOD
Clostridium. Tetani

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27
Q

What are microaerophiles?

A

Aerobes that prefer a small amount of oxygen

Neisseria and Borella

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28
Q

What is a major anaerobic component of gut bacteria that that causes disease? Under what conditions will it cause disease?

A

Bacteroides

If the barrier is compromised

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29
Q

A bacteria described as gram positive cocci, clusters, catalase and coagulase positive is likely _

A

Staph aureus

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30
Q

A bacteria described as gram positive cocci, chains, SOD positive but no catalase is likely _

A

Streptococcus

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31
Q

A major difference between Staph and Strep is _

A

Catalase activity in staph but not strep

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32
Q

Bacterioides is an anaerobe that is able to survive in the human gut despite the presence of oxygen. Why?

A

Because other bacteria like e.coli use up the oxygen

33
Q

Focusing on the gram positive cocci, a catalase positive cocci is likely _, If it is also coagulase positive, then the cocci is likely _

A

Streptococcus

Strep Aureus

34
Q

A gram positive, catalase negative cocci is either _ (2). If it undergoes betahemolysis and is bacitracin sensitive, then it is _. If is undergoes alpha hemolysis and is optochin sensitive then it is _

A

streptococci or enterococci
Group A streptococci
Streptococcus pneumoniae

35
Q

An gram positive cocci, obligate anaerobe is likely _

A

Peptostreptococcus

36
Q

What are the 2 gram positive rods that are also aerobes?

A

– Corynebacterium (aerobe)

– Listeria (aerobe)

37
Q

What are the 3 anaerobes gram positve rods discussed? Where are they found?

A 
Propionibacterium 
Lactobacillus (dominant mucosal flora)
Bifidobacterium (GI of breast fed babies)
38
Q

What are the 2 spore forming gram positive rods?

A

Bacillus and Clostridium

39
Q

What are the 2 gram negative cocci provided as examples? Which is a diplococci?

A

Neisseria (diplococci)

Acinetobacter

40
Q

What are the 4 gram negative rods provided as examples?

A
  • Enterobacteriaceae (facultative)
  • Pseudomonadaceae (aerobes)
  • Bacteroides, Fusobacterium (anaerobes)
41
Q

A gram negative rod that is oxidase negative is likely _. What sort of test can be used to identify these organisms?

A

Enterobacteriaceae

Lactose utilization test

42
Q

What are the 2 members of Enterobacteriaceae that are pathogenic and lactose negative? What diseases do they cause?

A

Salmonella - Typhoid and gastroenteritis

Shigella - Dysentery

43
Q

The lactose positive members of the Enterobacteriaceae class are usually _ type of pathogen. 4 examples are _

A 
Opportunistic 
E. coli 
Enterobacter
Klebsiella 
Proteus
44
Q

What is McConkey agar? What color does it turn for lactose positive organisms? What about lactose negative organisms?

A

Agar high in lactose, low in glucose
Lactose positive - Turn pink (acid products of fermentation)
Lactose negative - White (clear)

45
Q

How do gram positive organisms grow in McConkey agar?

A

Poorly, Their growth is inhibited

46
Q

What is another use for McConkey agar?

A

Used to determine coliform counts in fresh water lakes

47
Q

How many steps are involved in the identification of Enterobacteriaceae?

A

2
Step 1- Mcconkey
Step 2 - several others, including Mass Spec. don’t need to know for lecture

48
Q

What is a mesophile? What are 2 examples of pathogens that aren’t mesophiles?

A

Ability to grow at human temperature (most pathogens)
Mycobacterium leprae (skin)
Dermatophytes (skin)

49
Q

What is the value of fever, especially since it can increase production of exotoxins?

A

Primitive immune response, idea being that some microbes (not necessarily pathogens) cannot grow well at elevated temps

50
Q

What is an additional requirement of bacterial cells to be able to grow at fever temperatures? How do hosts keep this requirement away from bacteria?

A

Increased iron needed

Sequestering the iron in transferrin

51
Q

What bacterial molecules are used to scavenge iron? How are they expressed?

A

Siderophores

Either cell associated or secreted

52
Q

How can iron storage diseases affect bacterial pathogenicity?

A

Iron storage diseases where you can have increased iron can provide a required molecule for the bacteria to survive, even at elevated temperatures. Can increase opportunistic infections

53
Q

What is the protein required for bacterial transcription? What are its 5 components? Where does it terminate and what does termination require?

A

DNA dependent RNA polymerase
2 alpha chains, 2 beta chains, 1 sigma factor for initiation
Hairpin turn, rho factor may be required

54
Q

A specific type of bacteria that ciprofloxacin is effective against is _. A specific type of infection that norfloxacin is used to treat is _

A

Gram negative bacteria

Urinary tract infection

55
Q

What is a specific use for metronidazole highlighted in the notes? What two types of bacteria does it target? What is its mechanism?

A 
Trichomonas vaginalis (UTI)
Anaerobes and microaerophiles 
Intercalates into DNA, prevents replication
56
Q

What are the 4 examples of quinolone antibiotics provided? What is a specific risk associated with the fluoroquinolones? Which ones are they*?

A 
Naladixic acid, 
Ciprofloxacin, *
Norfloxacin, *
Ofloxacin*
* Weaken tendons, tendons burst / tear
57
Q

What is the class of antibiotics that target the DNA gyrase? What is their mechanism?

A

Quinolone antibiotics

Block topoisomerase II and IV, prevent the formation of phosphodiester bonds

58
Q

What is the protein required for DNA replication highlighted in the notes? What subunit of this protein was similarly highlighted in the notes?

A

DNA dependent DNA polymerase

DNA gyrase

59
Q

What is the word used to described DNA replication? Where does it start?

A

Semi-conservative

At Ori, the origin of replication

60
Q

What are 2 antibiotics that interfere with bacterial transcription? What is a special property of these drugs? What will these drugs do to urine? How are they administered and why?

A

Rifampin and rifamycin
High mucosal surface penetrating antibiotic
Cause urine to turn red
Used with other antibiotics, because of high chance of resistance if used alone

61
Q

What bacteria will not develop resistance to rifampin even if used alone? What bacteria certainly will?

A

Neisseria will not develop resistance

Staphylococcus will

62
Q

What is the major bacteria associated with 80% of enterocolitis? What is the bacteria associated with the other 20%

A

CLostridium difficile

Staph Aureus

63
Q

What is a specific good use of clindamycin? What is a very serious risk associated with its use? What is an eukaryote specific side effect?

A

Inhibits toxins from many bacteria (blocks toxin synthesis)
Allows growth of clostridium dificil leading to pseudomembranous enterocolitis
Affects eukaryote membranes

64
Q

The macrolide antibiotics include what 3 highlighted in class? What is a good use for these drugs?

A

Erythromycin, Azithromycin and clarithromycin

Used in penicillin allergic patients

65
Q

Chloramphenicol is a drug that is used to treat gram _ bacteria, but it is rarely used today. Why? What compartment is it particularly good at penetrating?

A

Gram negative
Can cause aplastic anemia
CNS

66
Q

Where do ribsosomes bind to initiate translation? What are the 2 components of the bacterial ribosome and what do they form? What are the 2 components of the eukaryotic ribosome and what do they form?

A

Shine Delgarno Sequence
30S and 50S form 70S ribosome (bacteria 357)
40S and 40S form 80S ribosome (euks 468)

67
Q

What are the 4 examples of aminoglycosides highlighted in the notes? What are they used for? What is their mechanism? What are 2 toxicities associated with them?

A

gentamicin, amikacin, kanamycin, tobramycin
Used on hard kill gram negatives
Cause tRNA misreading, binds ribosomes cause to fall off
Ototoxicity and nephrotoxicity

68
Q

What class of antibiotics Is particularly useful for treating pseudomonas in cystic fibrosis patients? What is pseudomonas’ gram classification? What setting is this class of drug used in?

A

Aminoglycosides
Gram negative
Hospital to monitor blood levels

69
Q

Tetracyclines include what 2 drugs mentioned in the notes? What is their spectrum? What specific disease are they used to treat? Who shouldn’t use these drugs and why?

A

Tetracycline and doxycycline
Broad spectrum
Chronic acne
Infants and pregnant mothers, binds and stains calcium

70
Q

What is a new protein synthesis inhibitor used for the treatment of MRSA?

A

Linezolid

71
Q

What is a topical protein synthesis inhibitor mentioned in class? What is it used to treat (2)?

A

Mupirocin

  • Staph and strep impetigo
  • decolonize nose prior of staph aureus prior to surgery (with chlorhexidine)
72
Q

Tetracyclines include what 2 drugs mentioned in the notes? What is their spectrum? What specific disease are they used to treat? Who shouldn’t use these drugs and why?

A

Tetracycline and doxycycline
Broad spectrum
Chronic acne
Infants and pregnant mothers, binds and stains calcium

73
Q

Why is polymixin B not more widely used? What is its main current use?

A

Toxic because it affects all plasma membranes

Used on affinity columns to remove LPS

74
Q

Beyond vancomycin, what other antibiotic can be used for MRSA?

A

Daptomycin

75
Q

Why are Sulfonamides and Trimethoprim used in combination? Which is specific for bacteria? Which is selective? What type of bacteria do they target? What non-bacteria do they target?

A 
Synergistic inhibitors of folic acid metabolism
Specific - sulfonamide 
Selective - Trimetoprim 
Target aerobic and facultative 
Pneumocystis carinii - fungus
76
Q

There are 6 antimycobaterial provided in class. What are they? How are they used?

A 
Isoniazid 
Pyrazidamine 
Ethambutol 
Capreomycin 
Clofazamine 
Ciprofloxacin 
Cycloserine 
Rifampin
Used in combination (2-3) for six months
77
Q

What is the minimum inhibitor concentration vs. the minimum bactericidal concentration?

A

Minimum inhibitory - is amount to limit growth

Minimum bactericidal is amount enough to cause a 3 log drop in bacterial concentration

78
Q

What is the Kirby Bauer test? What does it tell you?

A

Put a disc of antibiotic on a plate of bacteria and see how much it kills. Will tell you if bacteria are sensitive, intermediate or resistant

79
Q

What do you need to see using the tube test to determine the minimum bactericidal concentration?

A

Need to see concentration where bacteria stop growing

PID Exams (17 decks)

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