Exam 2 Lecture 14 Flashcards by Aditi Iyer

Clinically important Haemophilus species:

H. influenzae

2. H. ducreyi

How well did you know this?

Not at all

Perfectly

Haemophilus Gram Stain

Gram negative, thin, coccobacilli/short rods

How well did you know this?

Not at all

Perfectly

Why do we care about H. influenzae diseases?

we have a safe vaccine, but there are still hundreds to thousands of cases of severe disease/deaths

How well did you know this?

Not at all

Perfectly

True or false: On the evolutionary tree shown in lecture, there are a bunch of “H. flu”s grouped together, so they are evolutionarily very related to one another.

True

How well did you know this?

Not at all

Perfectly

True or false: H. ducreyi is slightly different than H. flu both clinically and genetically.

True

How well did you know this?

Not at all

Perfectly

H. flu grows on what media? What do the colonies look like on media?

Chocolate agar; flat/convex

How well did you know this?

Not at all

Perfectly

Haemophilus spp are ____ ____, so they can grow both aerobically and anaerobically.

facultative anaerobes

How well did you know this?

Not at all

Perfectly

Both H. flu and H. ducreyi like to grow with ___ supplementation

5% CO2

How well did you know this?

Not at all

Perfectly

H. flu likes to grow at __-__ ºC

35-37 (right around body temp)

How well did you know this?

Not at all

Perfectly

H. ducreyi likes to grow at __-__ ºC

33-35

How well did you know this?

Not at all

Perfectly

True or false: clinically, we usually are not able to grow H. flu on media, but we can more easily grow H. ducreyi

False: clinically we usually cannot grow H. ducreyi

How well did you know this?

Not at all

Perfectly

Haemophilus spp are __-___ and do not form ____.

non-motile; spores

How well did you know this?

Not at all

Perfectly

Haemophilus spp are _____ and require these two factors in order to be cultivated:

fastidious; Protoporphyrin IX (X factor) and NAD (V factor)

How well did you know this?

Not at all

Perfectly

What does Haemophilus ferment?

Glucose

How well did you know this?

Not at all

Perfectly

Haemophilus cannot ferment ____. Therefore, it will grow on ____ ___ but won’t turn pink.

lactate; MacConkey agar

How well did you know this?

Not at all

Perfectly

How can X factor and V factor be acquired?

by lysing erythrocytes (thus why H. influenzae is grown on chocolate agar)

How well did you know this?

Not at all

Perfectly

Haemophilus spp are ____ and ____-positive.

catalase and oxidase

How well did you know this?

Not at all

Perfectly

Haemophilus spp can reduce ____ to ____

nitrate to nitrite

How well did you know this?

Not at all

Perfectly

Which Haemophilus species may grow on blood agar?

H. haemolyticus

How well did you know this?

Not at all

Perfectly

True or false: H. influenzae must be encapsulated in order to be pathogenic.

False. Can be encapsulated (serotypes a through f) or not (NTHI)

How well did you know this?

Not at all

Perfectly

Which H. influenzae serotype have we created a vaccine against?

Type B (Hib)

How well did you know this?

Not at all

Perfectly

H. influenzae Type B _____ capsule is comprised of ___, which is strongly associated with ____.

polysaccharide; PRP (polyribitol phosphate); virulence

How well did you know this?

Not at all

Perfectly

What are some characteristics of NTHI? (3)

non-encapsulated
typically colonizes the nasopharynx
majority of diseases now caused by NTHI

How well did you know this?

Not at all

Perfectly

Why is majority of disease now NTHI?

Increase in vaccinations against Hib creates a hole in the population, which is filled by NTHI

How well did you know this?

Not at all

Perfectly

2 important things to know about Type B capsule

1. leads to immune escape (anti-phagocytic) | 2. is a component of the vaccine

Describe the epidemiology of H. influenza incidences before vaccination

mainly young children of school age were affected, especially 4 y.o.

What are 2 main severe diseases that can arise from H. influenzae infection?

1. Meningitis (50%) | 2. Epiglottits (17%)

What happened to disease incidences once the Hib vaccine was introduced?

Drastically changed the epidemiology - as we started to vaccinate, number of incidences drastically reduced to almost 0

What are the consequences of Hib vaccinations? (hint: think about relationship between Hib and NTHI)

shift in epidemiology - as Hib decreased, NTHI increased, meaning that more H. flu infections are caused by NTHI compared to before vaccination

Once H. influenzae enters the ____, the organism can disseminate into the ear canal and can cause ___ ___ ____.

nasopharynx; acute otitis media

What are some symptoms of AOM?

bulging tympanic membrane, redness, swelling, pus

ABM stands for:

acute bacterial meningitis

H. influenza can also infect the eye, causing _____.

conjunctivitis

Why is epiglottitis so life threatening?

The swelling that results from the infection can be a point of potential constriction in the proximal airway. It can also be difficult to get a breathing tube through.

True or false: H. influenzae can also cause lower respiratory tract infections, such as pneumonia.

True

There are __ patient populations of H. flu-induced pneumonia, which include:

2; 1. Kids 4 months - 4 years old 2. Older adults with bronchociliary dysfunction (can't clear mucus/bacteria)

Besides the Type B capsule, what other virulence factors does H. influenzae have?

Adhesins such as Protein E, OMP2, Type IV Pilus

Which antibiotics can be used to treat H. influenzae infection?

Amoxicillin (aminopenicillin) or Amox-Clavulonate (w/ beta-lactamase inhibitor)

True or false: H. influenzae has a lot of antibiotic resistance

False: there is some antibiotic resistance, but generally narrow beta-lactamase resistance

True or false: If the H. flu infection is serious, we can use IV antibiotics such as vancomycin.

False: we can use IV, but use ceftriaxone, cefotax, amp-sulbactam

H. aegyptius causes:

conjunctivitis

H. parainfluenzae causes:

AOM, sinusitis (also H. influenzae)

H. haemolyticus causes:

invasive disease

Sequencing distinguishes H. haemolyticus from ______

H. influenzae

H. ducreyi causes disease that is clinically similar to____

syphilis

True or false: H. ducreyi is not a prevalent pathogen in the U.S.

True (roughly dozen cases/year)

How does chancroid present?

multiple ulcerated lesions, adenopathy, pain at the site of the ulcerated lesion, gray/yellow exudate

Which of these symptoms is a key clue that distinguishes chancroid vs primary syphilis? A. ulcerated lesion appearance B. pain C. neither

pain

H. ducreyi can __-____ with other STIs and it is treated empirically with ____.

co-occur; Beta lactams

True or false: once you have been infected with H. ducreyi, you will have life-long immunity.

False

Bordetella Gram Stain

gram negative, coccobacilli/short rods

___-___ is a common media used to cultivate Bordetella, and colonies usually show up as:

Regan-Lowe; small, shiny/silvery, round, domed

When growing Bordetella in ___-___ media, there is slight hemolysis.

Bordet-Gengou

True or false: Bordetella is is a facultative aerobe.

False: strict aerobe

True or false: Bordetella is not encapsulated nor forms spores

True

Bordetella is ____ positive.

Oxidase

True or false: B. bronchiseptica is motile

true

B. parapertussis has ___ ____

brown pigment

True or false: B. bronchiseptica and rare Bordetella spp can grow on MacConkeys

True

The reservoir of B. pertussis is ___, ____, and __ ____. Do these people usually get whooping cough?

adults; adolescents; older children; no, but can get chronic cough

Where do we commonly see B. pertussis disease?

unimmunized patients, young babies (< 6 months), no immune system

Clinical pertussis is characterized by: (4)

1. prolonged cough 2. distinct whoop 3. CFU #'s decrease over time 4. lymphocytosis

Those with clinical pertussis are most infectious at: | and most non-infectious at:

~ 3 weeks; ~4-5 weeks

B. pertussis produces ____ ____, which can stick to ciliated airways, but not ____.

filamentous hemagglutin; alveoli

Catarrhal phase

bacterial load is high; cough may start; infectious but not sure if it's whooping cough at this stage

Intensity of whooping cough peaks at around:

2-3 weeks

B. pertussis produces toxins such as:

1. Adenylate Cyclase Toxin 2. Pertussis toxin 3. Tracheal cytotoxin

Important virulence/adherence factors for B. pertussis

FHA, Toxins, Fimbriae

FHA structure/function

big, long structure that allows relatively close contact with epithelium

Pertussis toxin contains __ and __ subunit, similar to DT toxin. Intake of Pertussis toxin leads to:

A; B; shuts down immune cell response

Adenylate cyclase toxin function

impairs macrophage function by suppressing nitric oxide production

Pertussis treatment

Macrolides (erythromycin for babies); intubation/ventilation for respiratory distress