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Microbiology > Haemophilus and Other Fastidious > Flashcards

Haemophilus and Other Fastidious Flashcards

1
Q

Pasteurellaceae (Pasteurella and Haemophilus)

A
  • gram-negative coccobacilli
  • non-motile, aerobic to facultative
  • reduce nitrate to nitrite
  • oxidase + and catalase +
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2
Q
  • obligate parasites of mucous membranes
  • require X and V factor
  • grow on chocolate agar
  • part of normal flora of upper respiratory tract
A

Haemophilus

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3
Q

Haemophilus means _______

A

blood loving

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4
Q

X factor

A

hemin (hematin)

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5
Q

V factor

A

nicotinamide-adenine dinucleotide (NAD)

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6
Q

only require V factor

A

para- Haemophilus species

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7
Q

Hemolysis on 5% horse or rabbit blood agar

A
  • H. hemolyticus and H. ducreyi

- can’t use SBA because it doesn’t have V factor

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8
Q

Growth patterns

A
  • satellitism around S. aureus (and species that release V factor)
  • exceptions: H. aphrophilus and H. ducreyi
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9
Q

H. influenzae

A
  • often a secondary infection (was in a pandemic)

- can test for beta-lactamase

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10
Q

H. influenzae (virulence factors)

A
  • capsule (A-F types)
  • IgA protease
  • outer membrane proteins and lipopolysaccharide (LPS)
  • adherence (pili)
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11
Q

H. influenzae capsule

A
  • antiphagocytic molecules (ribose, ribitol, and phosphate)

- nontypable strains cause localized infections (pneumonia, otitis media, sinusitis)

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12
Q

Haemophilus influenzae serotype b (Hib)

A
  • primarily in children
  • bacteremia can spread to tissues
  • # 1 cause of meningitis in unvaccinated children
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13
Q

Clinical disease of Hib

A
  • meningitis (children under 6)
  • epiglottitis (can cause airway obstruction)
  • bacterial tracheitis
  • cellulitis, pharyngitis, pneumonia
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14
Q

Non-encapsulated H. influenzae (diseases)

A

otitis media, bronchitis, sinusitis, pneumonia

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15
Q

H. aegyptius is the causative agent of _________

A

pinkeye (conjunctivitis)

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16
Q

H. aegyptius (clinical infections)

A
  • conjunctivitis

- Brazilian purpuric fever (BPF): has a high mortality rate

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17
Q

H. ducreyi

A
  • sexually transmitted infection
  • chancroid (soft chancre)
  • incubation up to 14 days
  • painful legion, enlarged lymph nodes, buboes
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18
Q

H. parainfluenzae (clinical infections)

A

endocarditis

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19
Q

H. aphrophilus/Aggregatibacter aphrophilus (clinical infections)

A

bite wound infections, endocarditis

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20
Q

Culturing Haemophilus

A
  • must plate immediately, they die rapidly
  • BAP for those that don’t require V factor
  • DON’T GROW ON MAC
  • transluscent, moist, smooth colonies
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21
Q

Culturing H. influenzae

A

chocolate agar with bacitracin (to inhibit other respiratory flora)

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22
Q

Culturing H. ducreyi

A
  • extremely fastidious (7 days to grow)

- “school of fish” morphology on gram stain

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23
Q

Lab ID of Haemophilus

A
  • place colonies in nutrient broth, then streak Mueller-Hinton agar plate, use X and V strips and incubate
  • Quad plate to ID factors needed (X, V, X & V, horse blood)
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24
Q

Porphyrin test

A
  • differentiates species that require X factor
  • Positive: organism converts delta-aminolevulinic acid to porphyrin (intermediate of X factor)
  • positive result means organism doesn’t need X factor
  • positive result on Wood lamp fluoresces
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25
Q

H. influenzae negative identification

A
  • from respiratory or CSF specimen
  • gram-neg. bacilli that have colonies >1mm on chocolate
  • no growth on SBA, except satellitism
  • negative porphyrin
26
Q

Haemophilus that require both X and V factors

A

H. influenzae, H. ageyptius, H. hemolyticus

27
Q

Haemophilus that requires only X factor

A

H. ducreyi

28
Q

HACEK

A
  • Haemophilus (Aggregatibacter aphrophilus)
  • Actinobacillus/Aggregatibacter actinomycetemcomitans
  • Cardiobacterium hominis
  • Eikenella corrodens
  • Kingella species
29
Q

HACEK (general characteristics)

A
  • none grow on Mac
  • requires CO2 for growth
  • usual flora of oral cavity (human bite wounds)
  • significant cause of endocarditis
30
Q
  • requires V factor

- associated with dental plaque

A

A. aphrophilus

31
Q
  • animal pathogen usually; gram-negative coccobacilli
  • distinctive star in center of colony
  • normal oral flora (causes peridontitis)
  • catalase +, oxidase variable
  • urease, indole, esculin, citrate -
A

Aggregatibacter actinomycetemcomitans

32
Q
  • non-motile, sometimes gram variable
  • “rosette” morphology
  • normal flora of nose, mouth and throat
  • may cause pitting on agar plates
A

Cardiobacterium hominis

33
Q

Cardiobacterium hominis

A
  • infects aortic valve

- causes endocarditis

34
Q
  • capnophilic, requires X factor
  • bleach-like odor
  • pitting in the agar
  • no growth on Mac or EMB
A

Eikenella corrodens

35
Q

Eikenella (clinical infections)

A
  • “clenched fist” bacteria (human bite/fight wounds)
  • pneumonia, meningitis, osteomyelitis, arthritis
  • cellulitis (when needles are licked clean - drug users)
  • endocarditis (least of HACEK group)
36
Q
  • non-motile, but may twitch
  • oxidase +, catalase -
  • found in upper respiratory tract
A

Kingella species

37
Q

Kingella kingae

A
  • grows on MTM, resembles gonhorrea
  • may pit on agar
  • catalase -, oxidase -
  • affects bones and joints of children
38
Q

Kingella dentrificans

A
  • catalase -, superoxol -

- differentiates it from Neisseria

39
Q

Capnocytophaga

A
  • resemble HACEK
  • gram-negative, fusiform, capnophilic
  • have gliding motility
  • dental problems, septicemia (if gets into blood)
40
Q

Pasteurella multocida

A
  • five serogroups (A-F)
  • bipolar staining (safety-pin appearance)
  • grow on BAP and Chocolate, no growth on MAC
  • zoonosis (dog or cat bites/scratches)
  • non-motile, catalase +, oxidase +
  • weak acid production
41
Q

Brucella

A
  • strict aerobes, non-spore forming, non-encapsulated
  • fine sand morphology (Brucella melitensis)
  • oxidase +, catalase +, H2S production, UREASE +
  • blood and bone marrow specimens typically
42
Q

Brucella (clinical infections)

A
  • Brucellosis and UNDULANT FEVER (long infection)
  • systemic infection with multi-organ involvement
  • zoonotic (animal contact, animal products)
  • infection via penetration of ocular or oral mucosa
  • lab-acquired infection
43
Q

undulant fever

A

fever recurring at regular intervals

44
Q

Francisella

A
  • require CYSTEINE for growth, grow on CAP, MTM, BCYE
  • strict aerobes, don’t grow on MAC, SBA
  • zoonotic infections
  • category A select agent
45
Q

organism that cause zoonotic infection

A

Pasteurella multocida, Brucella, Francisella

46
Q

F. tularensis

A
  • type A
  • transmitted by rabbits, sheep, ticks
  • rabbit fever
  • tularemia
47
Q

Other Francisella species

A

F. holarctica (type B), F. mediasiatica, F. novocida

48
Q

Legionella

A
  • acquired through inhalation (not zoonotic)
  • isolation on special media, identified by serologic testing
  • community-acquried pneumonia, nosocomial infections
  • environmental water sources, air conditioning systems
49
Q

L. pneumophilia

A
  • primary Legionella pathogen (16 serogroups)
  • virulence: ability to invade and survive in macrophages
  • results from inhalation of aerosols (not person-to-person)
  • Legionnaires’ disease
  • Pontiac fever
50
Q

Legionnaires’ disease

A
  • epidemic outbreaks usually from air conditioners
  • nosocomial infections (respiratory equipment and aerosol)
  • community-acquired pneumonia
  • cough, fever, headache, myalgia, dissemination via circulatory system
  • can have high mortality rate; hard to ID
51
Q

Pontiac fever

A
  • inhalation of Legionella
  • no pulmonary involvement
  • mild form of Legionnaires disease
52
Q

Legionella sources

A
  • aquatic sources
  • air conditioning systems
  • survive at large range of temps
  • adherence to pipes, rubber, plastics
  • can live intracellularly in protozoa
53
Q

Legionella specimens

A

predominantly respiratory specimens

54
Q

Legionella (characteristics)

A
  • difficult to ID
  • thin, weakly staining gram-negative rods; small colonies
  • blue-green colonies, ground-glass look
  • found within macrophages and neutrophils
  • aerobic, require Cysteine for growth
  • grow well on BCYE
55
Q

Bordetella (major pathogens)

A

Bordetella pertussis and Bordetella parapertussis

56
Q

Bordetella (minor pathogen)

A

Bordetella bronchiseptica - opportunistic, pneumonia and wound infections

57
Q

Bordetella (virulence)

A

Pertussis toxin - interferes with signal transduction

58
Q

Bordetella (infection)

A
  • acquired from breathing in aerosols (adheres to cells)
  • highly contagious, vaccine available
  • causes Whooping cough
59
Q

Whooping cough

A
  • presents with flu-like symptoms
  • highly contagious
  • severe repetitious coughing
  • can be followed by vomitting
  • serious in young children
  • causes hypoxia
60
Q

Culturing Bordetella

A
  • specimens from nasopharynx
  • MUST USE calcium alginate or Dacron swab
  • use Regan-Lowe transport medium or Bordet-Gengou potato infusion agar
  • incubates for 7 days
61
Q

Bordetella (characteristics)

A
  • gram-negative rod
  • obligate aerobe
  • smooth silver pinpoint colonies resembling mercury droplets

Microbiology (26 decks)

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