Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NPLEX I 2024 > Microbiology > Flashcards

Microbiology Flashcards

1
Q

appendages of bacteria and their purpose

A

flagellum
- protein
- motility

pilus/fimbria
- glycoprotein
- helps bacteria adhere to cell surface
- forms “sex pilus” during conjugation (transfer of DNA from one bacteria to another)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

components of bacterial cell envelopes

A

capsule (not all bacteria)
- polysaccharide
- protects against phagocytosis

slime (S) layer
- polysaccharides (loose network)
- helps with cell adhesion
- supports biofilm formation
- common in indwelling catheters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

why can encapsulated bacteria cause more severe disease?

A

the capsule prevents macrophages from identifying the bacteria before opsonization with Ab, can hangout in the body and cause damage longer before they are identified

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the important encapsulated bacteria?

A

Please SHine my SKis
- pseudomonas aeruginosa
- strep pnemoniae (not opsonized)
- H flu type B (not opsonized)
- neisseria meningitidis (not opsonized)
- e coli
- salmonella
- klebsiella pneumoniae
- group B strep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

components of outer membrane of gram negative bacteria

A

outer leaflet: endotoxin (LPS/LOS)
- lipid A induces TNF and IL1

embedded proteins
- porins: transport across outer membrance (transmission of substances)

inner leafleft: phospholipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

difference in outer cell wall between gram - and gram + bacteria

A

gram neg bacteria
- outer membrane
- periplasm (space between cytoplasmis membrane and outer membrane, peptidoglycan is in the middle) - hydrolytic enzymes can accumulate here as they exit

gram pos
- larger cell wall

both have cell walls made up of peptidoglycan sugar backbones with peptide side chains
- rigid support
- protection against osmotic pressure damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

composition of cytoplasmic membrane

A

phospholipid bilayer sac with embedded proteins
- penicillin binding proteins > help with cell wall synthesis
- lipoteichoic acids (gram + only) extend from membrane to outer exterior (induce TNFa and IL1)
- site of oxidative and transport enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

explain gram staining

A
  • crystal violent stain is applied
  • iodine (fixes stain)
  • alcohol (decolorizer; gram POS still retain violet dye due to their THICK peptidoglycan layer)
  • counterstain > gram NEG appear red/pink
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are spores?

A
  • only occur in gram POS bacteria (bacillus, clostridium)
  • kertain-like coat, contains peptidoglycan, and DNA
  • helps resist dehydration, heat, and chemicals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the urease positive organisms?

A

Pee CHUNKSS
- proteus
- cryptococcus
- H pylori
- Ureaplasma
- Nocardia
- Klebsiella
- S epidermidis
- S saprophyticus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

positive versus negative stains

A

positive
- basic
- bacteria are neg (proteins)
- take up pos stain
- bacteria will be in color under microscopy
- ex: methalene blue

negative
- acidic
- bacteria are neg
- repel neg stain
- bacteria will be white/clear w color background under microscopy
- ex: india ink, nigrosin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what bacteria can not gram stain and why?

A

These Little
Microbes
May Unfortunately
Lack Real Color, But Are Everywhere

  • Treponema, Leptospira (too thin)
  • Mycobacteria (cell wall with high lipid content)
  • Mycoplasma, Ureaplasma (no cell wall)
  • Legionella, Rickettsia, Chlamydia, Bartonella, Anaplasma, Ehrlichia (intracellular)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is an acid fast/ziehl-neelsen stain

A
  • stains acid fast bacteria (mycobacteria and nocardia)
  • uses carbol fuchsin > turns bacteria red
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is choc agar

A

heated up blood agar
IDs H flu

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is macconkey agar

A
  • fermentation produces acids
  • colonies turn pink
  • lactose-fermenting bacteria (enteric gram NEG) > colorless colonies
    -** lactose fermenters (e coli, citrobacter, klebsiella, enterobacter) > pink colonies**
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is eosin-methylene blue (EMB) agar

A

colonies have green metallic stain
IDs: E coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is sabouraud agar

A

fungi exclusively; too acidic for bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are anaerobes? give examples

A

Cant Breathe Fresh Air
- clostridium
- bacteroides
- fusobacterium
- actinomyces israelii

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the obligate intracellular bacteria

A

stay inside when its Really Chilld and Cold

  • rickettsia
  • chlamydia
  • coxiella
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the facultative intracellular bacteria

A

Some Nasty Bugs May Live FacultativeLY
- salmonella
- neisseria
- brucella
- mycobacterium
- listeria
- francisella
- legionella
- yersinia pestis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what does catalase do?

A

degrades H2O2 into water and oxygen; helps bacteria survive ROS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are the catalase positive organisms?

A

Big cats Have BeeN to PLACESS

  • bordatella pertussis
  • h pylori
  • burkholderia cepacia
  • nocardia
  • pseudomonas
  • listeria
  • aspergillus
  • candida
  • e coli
  • serratia
  • staphylococci
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

staphlycocci general characteristics

A
  • skin/mucous membranes
  • spherical cells in irregular clusters
  • gram pos
  • lack spores/flagella
  • may have capsules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

staph aureus effects, if any, on:
skin/skeletal

A
  • boils, carbuncles
  • impetigo
  • scalded skin syndrome
  • osteomyelitis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

staph aureus effects, if any, on:
CV, lymphatic, systemic

A
  • endocarditis
  • TSS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

staph aureus effects, if any, on:

GI

A

food intoxication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

staph aureus effects, if any, on:

respiratory

A

pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

coag-neg staph effects, if any, on:
skin/skeletal

A

surgical infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

coag-neg staph effects, if any, on:

CV/lymphatic/systemic

A

endocarditis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

coag-neg staph effects, if any, on:

urogenital

A

UTIs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

strep pyrogenes (group A) effects, if any, on:

skin/skeletal

A
  • pyoderma (impetigo)
  • erysipelas
  • necrotizing fasciitis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

strep pyrogenes (group A) effects, if any, on:

CV/lymphatic/systemic

A
  • scarlet fever
  • rheumatic fever
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

strep pyrogenes (group A) effects, if any, on:

respiratory

A
  • pharyngitis (strep throat)
  • sinusitis
34
Q

strep pyrogenes (group A) effects, if any, on:

urogenital

A

glomerulonephritis

35
Q

strep agalactiae (group B) effects, if any, on:

skin/skeletal

A

wound infections

36
Q

strep agalactiae (group B) effects, if any, on:

nervous/muscle

A

neonatal meningitis

37
Q

strep agalactiae (group B) effects, if any, on:

CV/lymphatic/systemic

A
  • neonatal sepsis
  • endocarditis
38
Q

strep agalactiae (group B) effects, if any, on:

respiratory

A

neonatal pneumonia

39
Q

enterococci effects, if any, on:

skin/skeletal

A

wound and surgical infections

40
Q

enterococci effects, if any, on:

urogenital

A

healthcare associated UTIs

41
Q

strep viridans effects, if any, on:

CV/lymphatic/systemic

A

subacute endocarditis

42
Q

strep viridans effects, if any, on:

GI

A

dental caries

43
Q

strep pneumoniae effects, if any, on:

nervous/muscle

A

pneumococcal meningitis (adult)

44
Q

strep pneumoniae effects, if any, on:

respiratory

A
  • pneumonia
  • otitis media
  • sinusitis
45
Q

neisseria gonorrhoeae effects, if any, on:

skin/skeletal

A

gonococcal opthalmia

46
Q

neisseria gonorrhoeae effects, if any, on:

urogenital

A

gonorrhea

47
Q

neisseria meningitidis effects, if any, on:

nevous/muscle

A

meningococcal meningitis

48
Q

staphylcoccus aureus general characteristics

A
  • grows in large, round, opaque colonies
  • facultative anaerobe
  • withstands high salt, pH extremes, high temps
  • produces many virulence factors
49
Q

staphylcoccus aureus epidemiology/pathogenesis

A
  • present in most environments frequented by humans
  • readily isolated from fomites
  • 20-60% in healthy adults in ant nares, skin, nasopharynx, intestine
  • inc in community acquired methicillin resistance (MRSA)
  • predisposition to infection: poor hygiene and nutrition, tissue injury, pre-existing primary infection, diabetes, immunodeficiency
50
Q

staph aureus pathology

A
  • localized skin infections (folliculitis, furuncle, carbuncle, impetigo)
  • osteomyelitis
  • bacteremia (>endocarditis)
  • toxigenic dz (food intoxication, scalded skin syndrome, TSS)
51
Q

coagulase negative staphylococci

A

healthcare associated and opportunistic infections in immunocompromised pts

  • S epidermidis - skin and mucus membranes (endocarditis, bacteremia, UTI)
  • S hominis - around apocrine sweat glands
  • S capitis - around scalp, face, external ear
    all three above can cause wound infections by penetrating through broken skin
  • S saprophyticus - infrequently lives on skin, intestine, vagina, UTI
52
Q

what differentiates staph aureus from other staph species?

A

coagulase POS

53
Q

streptococci general characteristics

A
  • gram pos spherical/ovoid cocci in long chains, usu pairs
  • non spore forming, non motile
  • can form capsules and slime layers
  • faculatative anaerobes
  • no catalase, but have peroxidase system
  • small, nonpigmented colonies
  • sensitive to drying, heat, disinfectants
  • most parasitic forms are fastidious and require enriched media
54
Q

streptococcus subspecies breakdown

A

beta hemomlytic
- bacitracin sensitive: group A strep (pyogenes)
- bacitracin resistant: group B, C strep

alpha hemolytic
- optochin sensitive: strep pneumoniae
- optochin resistant: group D, viridans strep

55
Q

strep pyogenes

hemolysis type
habitat
pathology

A

beta hemolytic
human throat
skin, throat infections, scarlet fever

56
Q

strep agalactiae

hemolysis type
habitat
pathology

A

beta hemolytic
human vagina, cow udder
neonatal, wound infections

57
Q

Strep equi

hemolysis type
habitat
pathology

A

beta hemolytic
various mammals
rare; abscesses

58
Q

Strep dysgalactiae

hemolysis type
habitat
pathology

A

beta hemolytic
cattle
rare

59
Q

enterococcus faecalis

hemolysis type
habitat
pathology

A

alpha, beta, N hemolytic
human, animal intestine
endocarditis, UTI

60
Q

E faecium, E durans

hemolysis type
habitat
pathology

A

alpha hemolytic
human, animal intestine
endocarditis, UTI

61
Q

strep bovis

hemolysis type
habitat
pathology

A

no hemolysis
cattle
subacute endocarditis, bacteremia

62
Q

Strep sanguinis

hemolysis type
habitat
pathology

A

alpha hemolytic
human oral cavity
endocarditis

63
Q

strep mutans

hemolysis type
habitat
pathology

A

no hemolysis
human oral cavity
dental caries

64
Q

Strep pneumoniae

hemolysis type
habitat
pathology

A

alpha hemolytic
human respiratory tract
bacterial pneumonia

65
Q

Strep anginosus

hemolysis type
habitat
pathology

A

beta hemolytic
humans, dogs
endocarditis, URT infections

66
Q

strep salivarius

hemolysis type
habitat
pathology

A

no hemolysis
human saliva
endocarditis

67
Q

strep pyogenes surface antigens

A
  • C carbohydrates: protects against lysozymes
  • fimbriae: adherence
  • M protein: resistance to phagocytosis
  • Hyluronic acid capsule: provokes no immune response
  • C5a protease: hinders complement and neutrophil response
68
Q

strep pyogenes major extracellular toxins

A
  • streptolysins (hemolysins): streptolysin O (SLO) and streptolysis (SLS); both cause cell and tissue injury
  • erythrogenic toxin (pyrogenic) - induces fever and typical red rash
  • superantigens - strong monocyte and lymphocyte stimulants; cause release of tissue necrosis factor
69
Q

strep pyogenes extracellular enzymes

A
  • streptokinase: digests fibrin clots
  • hyluronidase: breaks down CT
  • DNase - hydrolyzes DNA
70
Q

strep pyogenes epidemiology and pathogenesis

A
  • humans only reservoir
  • unapparent carriers
  • transmission: contact, droplets, food, fomites
  • portal of entry generally skin or pharynx
  • children predominant group for cutaneous and thraot infxns
  • sys infxn and progressive sequelae possible if untreated
71
Q

strep pyogenes pathology

A
  • skin infections (impetigo/pyoderma, erysipelas)
  • throat infections
  • systemic infections (scarlet fever via erythrogenic toxin, septicemia, TSS)
72
Q

strep pyogenes/group A strep
long-term complications

A
  • rheumatic fever: follows overt or subclinical pharyngitis in kids, carditis with extensive valve damage, arthritis, chorea, fever
  • acute glomerulonephritis (PSGN): nephritis, inc BP, occ HF, can become chronic > kidney failure
73
Q

strep agalactiae/Group B strep
location, transmission, pathology

A
  • resides in human vagina, pharynx, large intestine
  • can be transferred to infant during delivery and cause neonatal pneumonia, sepsis, and meningitis
  • wound and skin infections and endocarditis in immunocompromised people
74
Q

group D strep

name
location
pathology

A
  • enterococus faecalis, e faecium, e durans
  • normal colonists of human large intestine
  • cause opportunistic urinary, wound, and skin infections, esp in immunocompromised ppl
75
Q

groups C and G strep

location
pathology

A
  • common animal flora, frequently isolate from upper respiratory
  • pharyngitis, glomerulonephritis, bacteremia
76
Q

strep viridans general information

A
  • gums, teeth, oral cavity; nasopharynx, genital tract, skin
  • alpha hemolytic
  • not very invasive; dental/surgical procedures facilitate entrance
  • strep mutans, oralis, salivarus, sanguis, milleri, mitis
77
Q

strep viridans pathology

A

bacteremia, meningitis, abdominal infection, tooth abscesses

subacute endocarditis - blood bourne bacteria settle and grow on heart lining or valves
- ppl with preexisting heart dz at high risk
- colonization of heart by forming biofilms

78
Q

strep mutans pathology

A

slime layers that adhere to teeth > basis of plaque
- dental caries
- give ppl with preexisting heart conditions prophylactic antibiotics before surgery or dental procedures

79
Q

strep pneumoniae details and pathology

A
  • small, lanclet shaped cells in pairs and short chains
  • lack catalase and peroxidase (cultures die in O2)
  • culture requires blood or chocolate agar
  • causes 60-70% of bacterial pneumonias,
  • otitis media
80
Q
A

NPLEX I 2024 (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions