Microbiology Exam 2

Front 1

Enterococcus are more or less resistant to antimicrobial agents than streptococci? What are they resistant to?

Back 1

More resistant. Beta-lactams, clindamycin, and aminoglycosides

Front 2

Morphology and physiology of Enterococcus?

Back 2

G+ organisms, ovoid, appear in short chains, pairs, or single. Catalase (-)

Front 3

Antigenic structure of Enterococcus

Back 3

Group D streptococcal antigen

Front 4

Important clinical manifestations of Enterococcus?

Back 4

Nosocomial infections (hospital acquired), UTI (hospitalized patients), Endocarditis, Bacteremia (source is urinary tract), neonatal infections

Front 5

Lactobacillus is caused by exogenous or endogenous organisms?

Back 5

Endogenous

Front 6

Morphology and physiology of Lactobacillus?

Back 6

Morphology: G+, highly pleimorphic (variable in shape/size of cells)

Physiology: Facultative anaerobe, Produces lactic acid from sucrose, optimal pH~3.5-4.5

Front 7

What type of carries are Lactobacillus associated with?

Back 7

Secondary agents in dental carries following by Strep. Mutans

Smooth surface caries, in lesions that have progressed into the dentin, and root caries..

Front 8

Which bacteria is frequently resistant to cephalosporins, highly resistant to vancomycin, and not killed by penicillin alone (requires aminoglycoside)?

Back 8

Lactobacillus

Front 9

Major pathogen in genus corynebacteria?

Back 9

Corynebacterium Diptheriae

Front 10

Clinical manefectations of diptheria toxin?

Back 10

Prevents protein synthesis and kills affected cells

Front 11

Pathogenesis of Corynebacterium Diptheriae?

Back 11

Primarily pharynx; psuedomembrane is formed

Front 12

Highest incidence of Corynebacterium Diptheriae

Back 12

Occurs in unimmunized children under 10

Maintained by a small constant population of chronic carriers in the nose or nasopharynx.

Front 13

Transmission of Corynebacterium Diptheriae

Back 13

Droplets

Front 14

Describe the vaccine related to Corynebacterium diptheriae

Back 14

Vaccine is a modified toxoid/toxin

Front 15

Corynebacterium matruchotii shape

Back 15

Thich terminal ends = whip handle morphology

Front 16

Which bacteria comprises the central filament of "corn-cob" formations at the salivary interface of the supragingival plaque?

Back 16

Corynebacterium matruchotii

Front 17

Producers of the major by-product propionic acid?

Back 17

Propionibacterium
ex// P. acnes P. propionica

Front 18

Virculence factors associated with Propionibacterium?

Back 18

Lipase, protease, neuraminidase, hyaluronidase.

All stimulate an inflammatory response

Front 19

Propionibacterium attaches to steptococci gordonii and fusobacterium nucleatum. What does this signify

Back 19

Propionibacterium is an early colonizer

Front 20

Clinical manifestations of Propionibacterium?

Back 20

Involved in root caries

Inflammatory process in acne

Abcess development in jaw and infection of tear ducts (much less common)

Front 21

Treatment of Propionibacterium?

Back 21

Benzoyl peroxide for skin infections.

Erythromycin and clindamycin for others

Front 22

T/F Mycobacteria cause chronic lung infections

Back 22

True. Ex// M. Tuberculosis

Front 23

What is one of the few bacteria which are acid-fast (take up and retain red dye)?

Back 23

Mycobacteria

Front 24

Which lipids are responsible for acid-fastness?

Back 24

Mycolic acids (involved in pathogenicity)

Front 25

What does cord factor cause and which bacteria is it associated with?

Back 25

M. Tuberculosis

Causes the bacterium to grow in filaments

Front 26

What is the granulomatous response and which bacteria is it associated with.

Back 26

M. Tuberculosis

T cells, PMNs, and macrophages are attracted and accumulate near the bacteria.

May wall off lesions with a thick fibrin (tuberclue formed)

Front 27

(T/F) M. Tuberculosis demonstrates a high infectious dose with more than 1,000 organisms initiating infection

Back 27

F - Low dose with less than 10 organisms

Front 28

Chest x-rays, direct I.D. of acid-fast bacteria (AFB) in sputum, and culturing are types of tuberculin testing. What is the most common form of direct I.D.?

Back 28

Fluorescent direct ID

Front 29

How does the Tuberculin skin test (mantoux test) work?

Back 29

Inject PPD into forearm. An inflammatory response signifies that he person has previously had TB since pre-primed CD4+T helper cells are stimulated to secrete cytokines.

Cytokines recruit PMNs and macrophages to site.

Front 30

The interferon-gamma release assay test employs ________ _________ ________.

Which testing method is used to detect the release of interferon gamma?

Back 30

synthetic peptide antigens

Blood specimens containing T-cells are incubated with stimulated antigens and ELISA is used to detected the IG

Front 31

What is the "gold-standard" test used to diagnose Tuberculosis?

Back 31

Culturing and antibiograms to determine sensitivity.

Front 32

What is a rapid method of diagnosis of Tuberculosis?

Back 32

PCR and nucleic acid probes

Front 33

Why is it important to employ 2 or more drug against M. Tuberculosis?

Back 33

It helps prevent occurrence of resistant strains.

Front 34

What are the MAJOR pathogens in the Mycobacteria genus?

Back 34

M. tuberculosis, M. leprae, M.avium-intracellualar

"My LAT"

Front 35

What are the MAJOR pathogens in the Actinomycetaceae/ Actinomyces genus?

Back 35

A. israelii, A. naeslundii, A. viscosus, and A. odontolyticus

"A. NOVIce"

Front 36

Which organisms contain mycelial granules or "sulfur granules"?

Back 36

Actinomyces

Front 37

(T/F) Actinomyces produce endotoxin

Back 37

F.

Actinomyces do NOT produce toxins

Front 38

Where are granulomatous lesions found and which organisms are associated with them?

Back 38

Found within granules in sinus channels.

Associated with Actinomyces

Front 39

(T/F) Actinomyces manifest periodntal disease from biofilms

Back 39

True

Front 40

How to diagnost Actinomyces?

Back 40

Crush granules of clinical speciments and look for G(+) nonacid-fast diptheroids

Front 41

Species most commonly associated with cases of human actinomycosis

Back 41

Actinomyces israelii

Front 42

Which bacteria does Actinomyces israelii attach to in plaque?

Back 42

Prevotella loeschii and Fusobacterium nuceleatum

Front 43

(T/F) Actinomyces naeslundii preferentially colonize in plaque

Back 43

F.

Preferentially colonize the tongue and under mucosal surfaces

Front 44

Actinomyces naeslundii posesses 2 types of fibrils. Describe both

Back 44

Type 1: adheres to salivary pellicle coating teeth, specifically proline rich proteins and statherin

Type 2: adheres to mucosal cells and oral steptococci via fibril-borne lectin. Lectin is specific for beta-galatocsides and galactosamines

Front 45

What is the function of neuraminidase?

Back 45

It cleaves off sialic acid, exposing galactosides (mucosal cells) which are specifically bound by lectin (A. naeslundii)

Front 46

(T/F) Actinomyces naeslundii can colonize the oral caivty prior to tooth eruption?

Back 46

True

Front 47

(T/F) Actinomyces viscosus can colonize the oral caivty prior to tooth eruption?

Back 47

False

Preferentially colonizes teeth, unlike A. naeslundii

Front 48

Which organism is commonly associated with human gingivitis but NOT chronic periodontitis?

Back 48

A. Viscosus, whcih also adheres via Type 1 and Type 2 fibrils

Front 49

Nocardia can be found in ______ and the most common human infections is ______.

Back 49

soil environments

pneumonia

Front 50

(T/F) Rothia dentocariosa is associated with endocarditis.

Back 50

T

Front 51

What are the 4 major clinical group of Clostridia?

Back 51

Histotoxic - tissue infections

Enterotoxogenic- food poising and gi disease

C. Tetani- tetanus

C. botulinium - botulism

Front 52

C. perfringens requires a higher or lower oxidation-reduction potential for initiation of infection?

Back 52

Lower, resuting from muscle damage of muscle tissue

Front 53

What toxins are produced by C. perfringens?

Back 53

collagenass, proteinases, hyaluronidase, and deoxyribonuclease

Can infect necrotic tissue (clostridial cellulitis) or can cause an invasive infection (gas gangrene)

Front 54

What is the major cause of the clinical manifestations of C. perfringens?

Back 54

Usually follows trauma or a deep laceration

Front 55

What is the Naegler test used for?

Back 55

C. perfringens diagnosis

Front 56

Clostridium difficile causes which clinical manifestation?

Back 56

Pseudomembranous colitis and is associate with the use of certain antibiotics.

Other competitive flora are eliminated

Front 57

(T/F) Predisposing factors of Clostridium tetani include trauma and a drop in oxidation-reduction potential

Back 57

True

Front 58

What are the symptoms of C. tetani caused by?

Back 58

A neurotoxin (tetanospasmin) fixed to gangliosides and blocks the release of neurotransmitters

Front 59

How does neurotoxin A function and which organism is it released by?

Back 59

Released by C. Botulinum

Binds to receptor sites at the NMJ and prevents impulses by interfering with the release of acetylcholine

Front 60

Which organism is thought to play major roles in pathogeneis of both periodontal disease and endodontic infections?

Back 60

Black pigmenting bacteria (Bactroides) are important in oral infections

Front 61

Which organism is the most resistant of all anaerobes to antimicrobial agents?

Back 61

Bacteroides fragilis (oxymoron) which is Not a black-pigmenting organism

Front 62

Bacteroides fragilis is an endogenous or exogenous infection?

Back 62

Endogenous.

Found in the oral cavity, gi, vagina, and urethra

Front 63

Which antibiotics are used against Bacteroides fragilis and why?

Back 63

Metronidazole and clindamycin are effective since beta-lactamase is produced by most strains

Front 64

High numbers of this organism in the gingival crevice is strongly associated with peridontal disease, including chronic and localized aggressive periodontitis and abcesses of the periodontium. Active tissue and bone destrction occurs

Back 64

Tannerella forsythensis

Front 65

Which bacteria serves as reservoirs for re-colonization of the gingival crevice after periodontal treatment?

Back 65

Tannerella forsythensis and Porphyromnas gingivalis

Front 66

What are the 3 species in the Porphyromonas genus?

Back 66

P. gingivalis, P. endodontalis, P. asaccharolytica

Front 67

P. gingivalis is associated with which clinical manifestations? Like tannerella forsythensis

Back 67

Chronic and localized agressive periodontitis

Front 68

What are the virulence factors associated with P. gingivalis?

Back 68

fimbriae, capsules, collagenase, hyaluronidase, phospholipase, hemolysin, keratinases, and endotoxin (most damaging)

Front 69

T/F P. Gingivalis is an early colonizer

Back 69

False

It is a late colonizer and interacts with fusobacterium nucleatum and treponema species in plaque

Front 70

Which organism is most frequently associated with endodontic lesions?

Back 70

P. endodentalis which is a strict anaerobe.

Front 71

What is P. endodentalis's involvement in endodontic disease?

Back 71

Involves its ability to degrade collagen and a proteolytic activity

Front 72

What are the species of the Prevotella genus which are obligate anaerobes?

Back 72

P. intermedia, P. melaninogenica, and P. loeschii

Front 73

Associated with moderate to severe gingivits, necrotizing ulcerative gingivitis (NUG) chronic peridontitis, and peridontal abcess.

Back 73

P. intermedia

Front 74

Which bacteria contains the virulence factor alkaline phosphatase?

Back 74

Prevotella intermedia

Front 75

T/F Prevotella intermedia is a late colonizer

Back 75

True

Front 76

Fusobacterium nucleatum is also known as

Back 76

The big anchor

Front 77

Where is the major site of colonization of fusobacterium nucleatum?

Back 77

The gingival sulcus.

Also located in periodontal and gingivits lesions and from focal infections in the upper respiratory tract.

Front 78

What is the function of succinic acid and in which organism can it be found?

Back 78

It inhibits phagocytosis similarly to capsules and can be found on Fusobacterium nucleatum

Front 79

What are the common clinical manifestations associated with Fusobacterium nucleatum

Back 79

Acute necrotizing ulcerative gingivitis - necrosis and ulceration of papillae.

Necrotizing ulcerative periodontitis (NUP)

Gingivitis

Chronic/localized aggressive periodontitis

Vinvent's angina (ulcerative condition of the throat) as mixed infections with spirochetes (treponema)

Front 80

T/F Fusobacterium is a facultative anaerobe

Back 80

False

It is a strict anaerobe

Front 81

Antibiotics used with Fusobacterium nucleatum

Back 81

Metronidazole and clindamycin

Front 82

2 human Neisseria pathogens

Shape?

Back 82

Neisseria meningitidis, N. gonorrhoeae

Usually paired with adjacent sides flattened

Front 83

Primary antigen for serotyping of N.meningitidis

Back 83

capsular polysaccharides

Front 84

T/F Meningococcal LPS is a highly toxic endotoxin, moreso than other G- bacteria

Back 84

True!

Front 85

Abrupt onset of headache, stiff neck, and fever is a symptom of which disease?

Back 85

meningitis

Front 86

Clinical manifestations of Neisseria meningitidis

Back 86

fulminating maningococcemia (septicemia)

Meningitis

Front 87

How is meningitis normally transferred?

Back 87

prolonged contact of droplets

usually within closed population ex// college students living in dorms

Front 88

Does a positive nasopharyngeal culture of neisseria meningitidis diagnose meningitis?

Back 88

No, this only indicated carriage. The bacteria must be identified withing the blood, CSF , or skin lesions (occasionally)

Front 89

How to rule out strep pneumonaea as the cause of meningitis?

Back 89

High bacterial count in CSF points to Neisseria meningitidis

Front 90

Causes urethral strictures, epididymitis, and prostatitis

Back 90

Neisseria gonorrhoeae

epididymitis is caused by scar tissue blocking the epiddymus

Front 91

T/F gonorrhoeae is more prevalent in males

Back 91

False

20-80% of females are asymptomatic as well

Front 92

Salpingitis and PID are copmplications of what?

Back 92

Neisseria gonorrhoeae

Front 93

T/F Gonorrhoeae is the most common venereal disease in the us

Back 93

False

Chlamydia is the most comming, gonorrhoeae is second

Front 94

Tests used to diagnose Gonorrhoeae

Back 94

Gram stain with many PMNs with intracellular G- diplococci with flattened adjacent sides

ELISA using urethral pus

Genetic probes