Micro Cornyebacterium And Listeria

Front 1

What category do Corynebacterium and Listeria fall into?

Back 1

Both are Gram+ bacilli, non-spore forming. Listeria is motile while Corynebacterium is non-motile

Front 2

Both Corynebacterium and Listeria infect?

Back 2

The pediatric age group.

Front 3

What does Corynebacterium diptheriae infection cause?

Back 3

Colonizes the pharynx, forming a grayish pseudomembrane composed of fibrin, leukocytes, necrotic epithelial cells. From this site, bacteria releases exotoxin into bloodstream causing damage to the heart and neural cells resulting in diptheriae.

Front 4

Should you scrape of the tightly adherent pseudomembrane of diphtheria?

Back 4

No, bleeding will occur and absorption of the lethal exotoxin will be enhanced.

Front 5

Corynebacterium diphtheriae causes?

Back 5

Pseudomembrane, airway obstruction, with myocarditis, and polyneuritis

Front 6

How do you make a diagnosis of C. diphtheriae?

Back 6

Black colonies on potassium tellurite and Loeffler's coagulated blood serum

Note: characteristic gray-brown halo around the colonies. There are also normal diphtheroids, which commensally inhabit the pharynx and skin.

A modified plate test based on immunoprecipitation on agar can be performed to detect the toxigenic strain of C. diphtheriae.

Front 7

What is a prophylaxis for C. diphtheriae?

Back 7

DTaP: diphtheria, pertussis, and tetanus

Front 8

How do you treat C. diphtheriae?

Back 8

antitoxin (must be used quickly), penicillin or erythromycin (for local colonization)

Note: DTaP vaccine

Front 9

AB toxin from C. diphtheriae does?

Back 9

Can be considered a "human antibiotic" since it inhibits protein synthesis in cardiac and neural cells.

Note: The A fragment inhibits the protein synthesis intracellularly by ADP-ribosylation of elongation factor 2.

Front 10

Listeria monocytogenes cause?

Back 10

Listeriosis (meningitis and sepsis in neonates, immunocompromised)

Front 11

Listeria monocytogenes infect?

Back 11

Neonates, older individuals, immunocompromised, and pregnant women (3rd trimester when cell-mediated immunity is decreased)

Front 12

L. monocytogenes survives in?

Back 12

Poorly pasteurized milk. Pregnant women are told to avoid soft cheeses and cold cuts.

Front 13

L. monocytogenes in the host, stays within? Because of this, they are called?

Back 13

Intracellularly (macrophages, neutrophils) and extracellularly. Since L. monocytogenes can stay intracellularly, they are able to hide out in immunecompromised PT in which these individuals cannot activate their phagocytic cells. They are called facultative intracellular organism.

Front 14

How do you treat L. monocytogenes?

Back 14

TMP-SMX
ampicillin +/- gentamicin

Front 15

Clinical pearl: in adults over 50 years of age and in immunocompromised PTs who develop acute meningitis, add?

Back 15

ampicillin or trimethoprim sulfamethoxazole to empirically cover Listeria monocytogenes

Front 16

Listeria is the only Gram + with?

Back 16

An endotoxin

Front 17

C. diphtheriae is transmitted?

Back 17

Upper respiratory droplets and direct contact with skin lesions.

Front 18

What does C. diphtheriae cause in the nasopharynx?

Back 18

Gray fibrinous exudate (pseudomembrane) composed of bacteria, WBCs, and necrotic mucosa that may block airways. There can be paralysis of the palate and hypopharynx as an early local effect of the toxin.

Front 19

What are further complications from C. diphtheria?

Back 19

In addition to the pseudomembranes that can block airways, there can be myocarditis with cardiac arrhythmias and circulatory collapse and recurrent laryngeal nerve palsy. Also, cranial and peripheral nerve palsy.

Note: These extra effects are from circulating diphtheria toxin; therefore, do not scrape the pseudomomembrane because bleeding can result with spread of the toxin!

Front 20

Since cornyebacterium diptheriae use to be part of the normal flora (before DTaP), what causes the pathogenesis behind diphtheria?

Back 20

The toxin is carried by a phage, a temperate bacteriophage, carrying the tox gene, that encodes the diphtheria AB exotoxin.

Front 21

Corynebacterium diphtheriae looks like what on gram stain?

Back 21

Chinese letter.

Note:Löffler's serum, is used to preferentially grow C. diptheriae. After that, use a selective plate known as tellurite agar. The tellurite reduction is colormetrically indicated by brown colonies for most Cornyebacteria species or by a black halo around the C. diphtheriae colonies.

Selective tellurite media inhibits growth of normal oral flora, facilitating growth of C. diphtheriae.