L11- RTI III

Question 1

Streptococcus properties:

• Gram(+/-)
• (cocci/rods)
• catalase(+/-), but does contain (4)
• (non-/motile)
• most species are (obligate aerobes / obligate anaerobes / facultative anaerobes)

Answer 1

Gram+ cocci, catalase- but has Superoxide Dismutase (=> aerotolerant), non-motile, facultative anaerobes

Question 2

Strep. spp. are divided into groups through (1) agar, but are classified by (2)

Answer 2

1- blood agar (sheep) => α β γ

2- polysaccharide Ag in cell wall => Lancefield groupings

Question 3

GAS polysaccharide capsule is made out of…..

Answer 3

hyaluronic acid

Question 4

S. pneumoniae capsule has the (1) property which is used for (2)

Answer 4

1- quellung reaction: swollen capsule in presence of antiserum
2- serotyping S. pneumoniae

Question 5

S. pyogenes:

• blood agar result is (1), it is due to presence of (2)
• (3) is an important sensitivity/resistance property
• (4) is an additional and notable positive test result

Answer 5

1- β-hemolytic
2- Streptolysin S
3- Bacitracin sensitivity
4- PYR+ (pyrolidonyl arylamidase hydrolysis of L-pyrolidonyl-β-naphthylamide)

Question 6

S. pneumoniae:

• blood agar result is (1)
• (2) is an important sensitivity/resistance property

Answer 6

1- α-hemolytic

2- optochin sensitive

Question 7

S. pyogenes:

• pyogen = (1), because of (2) in the bacterium
• (3) reservoir
• (4) transmission

Answer 7

1- induces pus formation
2- leukocidin
3- human throat
4- direct contact, respiratory droplets

Question 8

list the syndromes caused by S. pyogenes

Answer 8

• pharyngitis (strep throat)
• skin infections (impetigo, etc)
• soft tissue infections
• rheumatic fever
• glomerulonephritis

Question 9

what properties of Strep. spp. contributed to the varying virulence factors between species

Answer 9

• transduction-mediated gene transfer (bacteriophages)

- transformation (DNA uptake from environment)

Question 10

S. pyogenes / GAS virulence factors:

• (1) and (2) are cell wall carbohydrate and protein respectively (indicate if they are for group/type)
• (3) for phagocytosis evasion
• (4) adherence / invasion
• (5) toxins

Answer 10

1- A antigen (group specific- same for all GAS)
2- M protein (type specific- serotype)

3- capsule, C5a peptide + (M/M-like proteins, F protein, Lipoteichoic acid)
4- M proteins, F protein, Lipoteichoic acid
5- Streptolysin S (RBCs), Streptolysin O (WBCs) + (SPE/strep. pyrogenic exotoxins, DNAse)

Question 11

describe the Sxs of GAS / Strep. pharyngitis

Answer 11

(suppurative GAS disease)

• inflamed pharynx with exudates
• anterior cervical lymphadenopathy

Question 12

describe the Sxs of Scarlet Fever

Answer 12

(suppurative GAS disease)
-via GAS, sequela to Pharyngitis

• diffuse erythematous rash: starts on trunk/chest –> moves to extremities
• strawberry tongue

Question 13

what are two non-suppurative diseases stemming from GAS

Answer 13

• Rheumatic Fever: type II sensitivity rxn

- Acute Glomerulonephritis:

Question 14

Rheumatic Fevers is caused by (1), proceeding (2). It results from a (3) type reaction. It is described symptomatically with the following: (4).

Answer 14

1- GAS
2- Strep. pharyngitis (2-4 wks)
3- type II hypersensitivity
4- endocarditis, polyarthritis, subcutaneous nodules, chorea (JONES criteria)

Question 15

Acute Glomerulonephritis can result after (1) infection of the (2). It presents symptomatically with (3).

Answer 15

1- GAS
2- pharyngitis (7-10 days) or impetigo (3 wks)
3- edema, HTN, hematuria, proteinuria

Question 16

Corynebacterium properties:

• Gram(+/-)
• (cocci/rods)
• (non-/spore forming)
• (aerobic/anaerobic)
• (5) color and shape appearance on slide

Answer 16

Gram+ rods, non-spore forming, aerobic

5:

• gray-to-black colonies
• shape is pleomorphic called ‘club-shaped’ / V/L shaped / ‘chinese letter arrangement’ —- this is due to snapping cell division (incomplete membrane separation)

Question 17

The main corynebacterium species that cause infection is (1), while many other species are (2)

Answer 17

1- C. diphtheriae

2- non-pathogenic members of flora in pharynx, nasopharynx, skin

Question 18

C. diphtheriae appears as (1) color in slides due to (2) produced on (3) mediums after staining the sample metachromatically.

Answer 18

1- gray-to-black
2- granules / volutin
3- Loeffler’s coagulated serum medium

Question 19

The most critical virulence factor that may be present in C. diphtheriae is…..

Answer 19

(toxin producing strains)
-β-prophage carries genes for toxin (lysogeny, β-corynephage)

Note- phage from toxin-diphtheria infected Pt can infect / transmit to non-toxin diphtheria infected Pt
**Mobile gene elements

Question 20

Respiratory Diphtheria:

• (1) regular Sxs
• (2) hallmark Sxs, include what it can lead too
• (3) severe manifestations

Answer 20

1- (sudden onset) exudative pharyngitis, sore throat, fever, malaise, dysphagia

2- i) thick pseudomembrane (dead cells / bacteria) –> can possibly cause respiratory obstruction; ii) bull neck appearance

3- myocarditis, recurrent laryngeal nerve palsy

Question 21

Cutaneous Diphtheria clinical presentation

Answer 21

• papule on skin progresses to healing ulcer

- systemic signs can develop

Question 22

C. diphtheria can be dangerous in (1) areas because of (2)

Answer 22

1- endemic in some subtropical and tropical countries (+ underdeveloped countries with poor health infrastructure)

2- diphtheria toxoid vaccine is apart of DTaP

Question 23

C. diphtheria is a unique organism because it is not (1) to yield systemic symptoms, instead (2) will cause systemic manifestations. (2) can be acquired in C. diphtheria via (3). (2) will specifically cause (4) and (5).

Answer 23

1- non-invasive, does not enter bloodstream
2- diphtheria exotoxin
3- bacteriophage (lysogenic conversion)
4- inflammation and formation of pseudomembrane
5- damage to organs

Question 24

list the medias for C. diphtheria

Answer 24

• Cysteine-Tellurite blood agar (CTBA)
• Tinsdale medium
• Colistin-nalidixic agar (CAN)

Question 25

what are the characteristics needed for Dx of C. diphtheria infection

Answer 25

(culture on selective media) -characteristic grey-to-black colonies with brown halo 1) tellurite reductase +, cystinase + 2) urease -, pyrazinamidase - 3) toxingenicity test: ELEK, PCR

Question 26

describe the ELEK test and what it is used for

Answer 26

Test for toxigenicity, specifically for C. diphtheria 1) incubation culture with a streak of known non-toxigenic strain and unknown, suspected toxigenic strain 2) place filter paper with anti-toxin 3) - Pos (toxigenic): lines of precipitin (area of no growth) - Neg (non-toxigenic): grows the same as the known non-toxigenic strain

Question 27

______ are common squeal of infection

Answer 27

- sinusitis | - acute otitis media (AOM)

Question 28

Sinusitis and AOM are mostly caused by (1) pathogens, including (2). The second most common pathogens are (3) including (4).

Answer 28

1- viruses 2- rhinovirus, adenovirus, coronavirus (same as rhinitis) 3- bacteria 4- Strep. pneumoniae, Haemophilus influenza, Moraxella catarrhalis

Question 29

describe the Sxs of sinusitis

Answer 29

(inflammation of any of the four pairs of sinuses) - bad breath / loss of smell - fatigue, fever, HA - pressure-like pain with facial tenderness + pain behind eyes, toothache - nasal congestion and discharge - cough (worse at night) - sore throat, postnasal drip

Question 30

AOM Sxs: (1) common Sxs (2) describe the TM (3) neonatal Sxs

Answer 30

1- fever, ear pain (ear tugging), hearing loss, ear stuffiness 2- (tympanic membrane) immobile, inflamed, perforated and or bulging of TM, ear discharge 3- irritability, feeding difficulties

Question 31

list the syndromes caused by Haemophilus influenzae

Answer 31

otitis media, sinusitis, pneumonia, epiglottitis, meningitis, COPD acute exacerbation

Question 32

(1) is the most common cause of epiglottitis, which is described as (2). (3) are other epiglottitis associated microbes.

Answer 32

1- haemophilus influenzae 2- epiglottic and supraglottic swelling / inflammation 3- C. diphtheria, N. meningitis Note- 90% of epiglottitis is caused by bacteria

Question 33

Haemophilus influenzae: - (small/large) - (2) shape [cocci/bacillus] - Gram(+/-) - coagulase(+/-) - catalase(+/-)

Answer 33

``` small Gram- coccobacilli with pleomorphic shape (shape is able to change / is variable) coagulase- catalase+ ```

Question 34

describe the 2 types of Haemophilus influenzae

Answer 34

Non-Typeable / Non-Encapsulated: - colonizes in URT of children / adults - causes otits media, sinusitis, COPD exacerbations Typeable / Capsulated: - serotyped a --> f - type b has invasive disease, Hib does have a vaccine - other types are apart of normal microbiota

Question 35

Haemophilus influenzae virulence factors: - (1) and (2) are for adhesion - (3) makes up capsule - (4) is a toxin - (5) is a useful protease

Answer 35

1- pili 2- non-pilus adhesins: P-2 outer membrane protein 3- PRP (polyribose ribitol phosphate) 4- LPS endotoxin impairs ciliary function 5- IgA proteases, >30 types

Question 36

describe the requirements for Haemophilus influenzae culture (and the appearance)

Answer 36

chocolate agar (heated blood agar) with the following factors: - X growth factor: acts as **hemin - V growth factor: **NAD (nicotinamide adenine dinnucleotide) **colonies appear large, round, opaque

Question 37

Haemophilus influenzae Epiglottitis clinical features / common Sxs

Answer 37

fever, sore throat, dys-/odyno-phagia, stridor, restlessness, drooling, hoarseness, muffled voice, **tripod position**

Question 38

describe tripod position sign in Haemophilus influenzae Epiglottitis

Answer 38

trunk leaning forward neck hyper-extended chin thrust forward

Question 39

describe radiological evidence for Haemophilus influenzae Epiglottitis

Answer 39

enlarged epiglottis = 'thumb sign' aryepiglottic folds thickening