Gram + Bacilli Flashcards

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1
Q

Non branching
Non spore forming
Gram + rods/bacilli

Only species of Listeria pathogenic for humans

Once phagocytosed by WBCs, it produces Listeriolysin O + phospholipase enabling it to escape from WBC and spreads to blood stream -> reaches CNS and placenta

A

Listeria monocytogenes

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2
Q

Listeria motility pattern

A

Tumbling motility of saline suspensions of colonies

occur at RT but rarely 5 deg

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3
Q

Tumbling motility
Inverted Christmas tree pattern

Across placenta or by contact during delivery

Ingestion of unpasteurized milk products (eg. cheese)

High risk group: pregnant women, neonates and immunocompromised

Pregnant women

A

Listeria monocytogenes

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4
Q

Listeria infection in pregnant most commonly occurs in

A

third trimester

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5
Q

Listeria risk factors

A

Bacteremia
Amnionitis
Premature labor or septic abortion in 3-7 days

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6
Q

Unpasteurized milk organisms

A

Brucella

Listeria

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7
Q

Neonatal sepsis
Neonata meningitis
Neonatal pneumonia

A

Group B Agalactiae
E coli
Listeria

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8
Q
Stillbirth
Granulomatosis infantisepticum (1st 4 days of life)
Meningitis
Meningoencephalitis
Brain abscess
Pneumonia
A

Listeria monocytogenes

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9
Q

Unpasteurized milk

Cabbage/coleslaw

A

Listeria

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10
Q

Listeria Tx

A

Ampicillin +/- Gentamycin

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11
Q

Ampicillin + Gentamycin SE

A

Nephrotoxicity

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12
Q

Aminoglycoside SE

A

Ototoxicity

Nephrotoxicity

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13
Q

Ampicillin SE

A

Interstitial nephritis

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14
Q
Catalase -
Non spore forming 
Non motile
Anaerobic
Gram + bacillus

Short rod with rounded ends occurs singly in short chains or in non branching filaments

A

Erysipelothrix

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15
Q

Animals to humans (skin wound produced by contaminated objects or in contact with blood, flesh, viscera or feces of infected animals)

At risk of infection, butchers, abattoir workers, fishermen, fish handlers, poultry processors and veterinarians

A

Erysipelothrix

Rhusiopathiae

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16
Q

Erysipelothrix virulence factors

A

Capsule
Neuraminidase
Hyaluronidase
Surface proteins

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17
Q

Most common form of erysipeloid

Pain, swelling, cutaneous eruption (slowly progressive, slightly elevated, violaceous zones around the site of inoculation)

A

Local cutaneous infection Erysipelothrix Rhusiopathiae

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18
Q

Best specimen for culture of Erysipelothrix

A

Biopsy

Tissue aspirates from erysipeloid lesions

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19
Q

Pipe cleaner pattern of growth in Gelatin Stab cultures incubated at 22 deg C

A

Erysipelothrix rhusiopathiae

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20
Q

Erysipelothrix rhusiopathiae tx

A

Penicillin

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21
Q

Most are Catalase -
Round terminal spores
Drumstick

True exotoxin

A

C tetani

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22
Q

Catalase +
Oval, subterminal spores
Tennis rackets

True exotoxin

A

C botulinum

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23
Q

Motile, drumstick appearance

Tetanospasmin inhibits GABA and Glycine

Muscle spasm, lock jaw, risus sardonicus, respiratory paralysis, opistothonusc

Dysautonomia

A

C tetani

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24
Q

C tetani tx

A
Metronidazole
Antitoxin 
Tetanus toxoid 
Spasmolytic drug
Penicillin
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25
Q

Long acting inhibitor of spasm

A

Benzodiazepine - Diazepam

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26
Q

Very potent neurotoxin and probably is solely responsible for the disease

A

Tetanospasmin

Tetanolysin

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27
Q

Spores germinate under anaerobic condition in the wound

A

C tetani

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28
Q

Protease that cleaves the proteins involved in the release of glycine from Renshaw cells of sc

Continuous stimulation by excitatory transmitter

A

Tetanus toxin (tetanospasmin)

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29
Q

Most common form of tetanus

A

Generalized tetanus

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30
Q

Earliest manifestation of generalized tetanus

A

Trismus

Lock jaw

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31
Q

Earliest manifestation of neonatal tetanus

A

Poor suck

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32
Q

Penicillin should not be used for c tetani because

A

it inhibits glycine

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33
Q
Nonmotile
Double zone of hemolysis
Alpha toxin (lecithinase) 
Clostridial myonecrosis
Nagler reaction +
A

Clostridium perfringens

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34
Q

C perfringens Tx

If with gas gangrene

A

Penicillin
Clindamycin

Add hyperbaric oxygen

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35
Q

C perfringens toxins

A

Lecithinase

Exotoxins

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36
Q

C perfringes in culture

A

Stormy fermentation
Litmus milk cultures
turbidity gas

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37
Q

Spectrum of C perfringens

A

Gas gangrene - pain, edema, cellulitis with crepitation, hemolysis and jaundice

Food poisoning - 8-16 h incubation period; characterized by watery diarrhea with cramps and little vomiting; resolves within 24 h

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38
Q

Nagler’s reaction in C perfringens tests

A

Lecithinase activity of alpha toxin

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39
Q

Gram +

Alpha toxin producing lecithinase

A

C perfringens

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40
Q

Myonecrosis
Skin crepitation
Gangrenous wound

Death march of bataan

A

C perfringens

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41
Q

Areas susceptible to gas gangrene

A

Axilla
Thigh
Buttocks

42
Q

C botulinum presentation

Lipase +

A

Foodborne - preformed toxin
Infant - ingestion of spores
Wound - contamination with spores

43
Q

Botulinum toxin blocks transmission of the neurotransmitter from motor nerve

A

Acetylcholine

44
Q

Food poisoning

Floppy baby syndrome

When babies ingest spores found in household dust or honey

Due to absence of competitive bowel microbes

Improperly canned or preserved food

A

C botulinum

45
Q

Can contain spores of bacteria and should not be fed to babies less than 1 year of age

A

Honey

46
Q

diplopia, dysphonia, dysarthria, dysphagia: bulbar signs

Anticholinergic effects from blockade of Ach: dry mouth, constipation, abdominal pain

Bilateral descending flaccid paralysis

Respiratory paralysis

A

C botulinum

47
Q

Traumatic implantation and germination of spores at the wound site

A

C botulinum

48
Q

Reheated fried rice

A

Bacillus cereus

49
Q

Reheated meat dishes

A

C perfringens

50
Q

Soft cheeses, deli, coleslaw

A

Listeria monocytogenes

51
Q

Honey

Home canned goods

A

C botulinum

52
Q

Unpasteurized milk products

A

L monocytogenes

53
Q

Motile

Toxin A - diarrhea
Toxin B - cytolytic to colonic epithelial cells

Pseudomembranous colitis

A

C difficile

54
Q

C difficile producing drugs

A

Clindamycin
Cephalosporin (cefotaxime, ceftriaxone, cefuroxime, ceftaz)
Amoxicillin
Ampicillin
Quinolone (ciprofloxacin, levofloxacin, moxifloxacin)

55
Q

C difficile Tx

A

Metronidazole - mild to moderate
Vancomycin - more effective, for severe
Fidaxomicin (macrolide)

Causative antibiotic should be withdrawn
Sx for toxic megacolon

56
Q

Acquired exogenously most frequently in the hospital or nursing home

Hospitalized at least 3-5 days

A

C difficile

57
Q

C difficile toxin

A
Toxin A (enterotoxin)
Toxin B (cytotoxin)
58
Q

Pseudomembranes of PMC are confined to colonic mucosa
Whitish plaques

Nonbloody diarrhea with pseudomembranes (yellow white plaques) on colonic mucosa

Toxic megacolon can occur

A

C difficile

59
Q

Most common presentation of C difficile

A

Diarrhea

60
Q

Most sensitive test for c difficile

A

Stool culture

61
Q

C difficile Dx

A

Cell culture cytotoxin test on stool enzyme immunoassay for C difficile common antigen in stool
Colonoscopy or sigmoidoscopy

62
Q

Facultative anaerobe
Grow best in inc CO2
Young colonies - Spider colonies (thin radiating filaments)

A

Actinomyces israelii

63
Q

Old colonies “molar tooth”

A

Actinomyces israelii

64
Q

Bacteria that thrive inc CO2

A

Capnophiles

65
Q

Mycetomas
Genital actinomycosis
Lumpy jaw with skin lesions - sulfur granules

A

Actinomyces israelii

66
Q

Actinomyces Tx

A

Ampicillin/sulbactam
Chloramphenicol
Imipinem
Ticarcillin/Clavulanic acid

67
Q

Causes seizure

A

Imipinem

68
Q

Chloramphenicol causes gray baby syndrome because they lack the enzyme

A

Glucoronyl transferase

69
Q

Renal dihydropeptidase inhibitor Added to imipinem to prevent degradation

A

Cilastin

70
Q

Clavulanic acid MOA

A

Beta lactam inhibitor

71
Q

Causes bone marrow supression

A

Chloramphenicol

72
Q

Aerobe

Non acid fast

A
Actinomadura
Streptomyces
Tsukumurella
Nocardiopsis
Rhodococcus
73
Q

Aerobe, weakly or partially acid fast

A

Nocardia

74
Q

Anaerobe, non acid fast
Filamentous branching
Sulfur granules

A

Anctinomyces

israelii

75
Q

Actinomyces Tx

A

Peniillin

76
Q

Nocardia tx

A

TMP-SMX

SNAP
Sulfo (TMP-SMZ) - Actinomyces

77
Q

Gram + actinomycete
Whipple’s disease (middle aged males), diarrhea, weight loss, arthralgia, lymhpadenopathy, hyperpigmentarion

Warthin starry stain

Infective endocarditis

A

Tropheryma whippeli

78
Q

T whippeli Dx

A

PCR

79
Q

T whippeli Tx

A

Penicillin
Colchicine
SXT

80
Q

Warthin starry stain

A

H pylori
Legionella
Bartonella
Spirochetes

81
Q

Found in soil and plant materials
Transmission in environmental person-to-person

2 forms

A

Pulmonary (farmer’s lung)

Cutaneous (mycetoma) - contain sulfur granules

82
Q

Nocardia asteroides Dx

A

Acid fast “paraffin bait” technique

83
Q

Long thin, beaded, branching, gram + bacilli

Most distinguishing quality of Partially acid fast

Differentiated them from Actinomyces (similar GS appearance but not acid fast)

Partial acid fastness: enhanced using Middlebrook 7H10 agar or litmus milk broth

Clinical infections: members of the Nocardia asteroides

A

Nocardia

84
Q

Nocardia asteroides complex

A

Nocardia cyriageorgica
Nocardia farcinica
Nocardia nova

Less common: Nocardia brasiliensis

Rare: Nocardia otitisis caviarum

85
Q

Phagocytosed by alveolar cell
Granuloma formation
Lymphocutaneous disease

A

Nocardia

86
Q

Gram negative
Aerobic
Coccobacilli

Incubation: 7-10 days no symptoms

A

B pertussis

87
Q

1-2 weeks

Rhinorrhea, malaise, sneezing, anorexia
Highest microbiologic yield

Most contagious

A

Catarrhal

88
Q

2-4 weeks; repetitive cough with whoops, vomiting, leukocytosis

A

Paroxysmal

89
Q

3-4 weeks

Diminished cough, secondary complications (pneumonia, seizure, encephalopathy)

A

Convalescent

90
Q

ADP ribosylation of B pertussis

A

Capsule Pertussis Toxin

91
Q

B pertussis toxin

A

Dermonecrotic toxin (DNT)
Capsule Pertussis Toxin
Tracheal cytotoxin

92
Q

B pertussis medium

A

Border Gengou medium

Regan-Lowe medium

93
Q

DPT vaccine that causes seizure

A

Pertussis

94
Q

Pertussis hallmark in lab diagnosis

A

Lymphocytosis

95
Q

Buffered Charcoal Yeast Extract Agar shows “mercury droplets” appearance

A

B pertussis

96
Q

Colony resembling a tiny drop of mercury

A

Mercury droplet colonies

97
Q

Whooping cough

Acute Tracheobronchitis

A

B pertussis

98
Q

Laryngotracheobronchitis

A

Croup

Parainfluenza

99
Q

steeple sign

A

Croup

Parainfluenza

100
Q

Pertussis Tx

1 month age or older

A

Macrolide (Azithromycin, Clarithromycin, Erythromycin)

Post exposure Antimicrobial Prophylaxis

101
Q

Macrolide SE when given to less than 1 month

A

Hypertrophic pyloric stenosis