Medical Microbiology Exam 2

Front 1

Mycobacterium biology

Back 1

1. Gram positive bacilli

2. Acid fast/waxy layer

3. OBLIGATE ANAEROBES

Front 2

Stages of tuberculosis

Back 2

1. Latent TB: no symptoms, not contagious, walled off with calcium deposits/tubercles

2. Pulmonary TB: consumption of lungs

3. Miliary (active) TB: spreads throughout body via lymphatics and blood w development if nodules

Front 3

Symptoms of tuberculosis

Back 3

Coughing up blood, chills, fever, night swrsts

Front 4

Epidemiology of tuberculosis

Back 4

MYCOBACTERIUM

1/3 of world population infected (most are latent), spreads person to person via droplet nuclei with close and prolonged contact, virulence is low in healthy individuals

Front 5

Tuberculin skin test (PPD)

Back 5

Tine test is notoriously inaccurate, intracutaneous is better, wheal and flare over 10 mm is

Front 6

IGRA

Back 6

Interferon Gamma Release Assay, blood test, relies on intact immune system, ahead of its time

Front 7

Vaccination of tuberculosis

Back 7

BCG (Bacille-Calmette-Guerin), isoniazid, rifampin, drug use/homelessness and economic struggle due to HIV epidemic in 80s

Front 8

Mycobacterium leprae biology

Back 8

MYCOBACTERIUM

Grows in cooler parts of body, armadillos, close contact with skin lesions and nasal mucus, 2-40 yr incubation period

Front 9

MOTTs (mycobacterium other than tuberculosis)

Back 9

Over 100 species of mycobacterium, MAC (M. avium-intracellulare complex) is most common for people with AIDS, rapid (7 days), found in soil, water, animals, milk, 25-45°C and a broad range of requirements

Front 10

History of tuberculosis

Back 10

-1882, caused 1/4 of adult deaths in Europe, discovered in unpasteurized milk (M. bovis)

-1946, modern TB treated with streptomycin (STM)

-1952, treated with isoniazid (INH)

-1970, rifampin (RMP)

-1985, rates increased again due to HIV, MDR tuberculosis

-1990, continues to grow

-1992, new cases have reached a maximum

-today, half of the cases in 1992

Front 11

"Consumption"

Back 11

Tuberculosis is called consumption because it consumes your lungs. Walled off area in lungs composed of WBCs, calcium salts, and fibrous material

Front 12

Treatment of tuberculosis

Back 12

First line drugs: Isoniazid (INH), Rifampin (RMP), Ethambutol, pyrazinamide for MDR tuberculosis

Front 13

Leprosy disease

Back 13

Clinical manifestations confined to skin, upper respiratory system, testes, and peripheral nerves. All ages affected.

Front 14

Treatment of leprosy

Back 14

M. leprae is treatable and curable but disfigurations are permanent

Front 15

Mycobacterium identification techniques

Back 15

1.) Nucleic Acid probes/amplification: for most common mycobacterium

2.) Nucleic Acid sequencing: identifies bacteria other than M. tuberculosis and MAC

3.) MALDI-TOF MS: pattern recognition technology

4.) Analysis of fatty acids: chromatography, for all species

Front 16

Enterobacteriaceae characteristics

Back 16

•nonsporeforming

•facultative anaerobes

•gram negative rods

•ferment glucose

•reduce nitrates to nitrites

•do not produce cytochrome oxidase

•slang name: enterics

Front 17

Natural habitat of enterobacteriaceae

Back 17

•ubiquitous (everywhere)

•most species are found in normal microbiome of intestinal tract of humans and animals

•some live freely in soil, water, sewer, some are known to be plant pathogens

Front 18

Antigenic structure of Enterobacteriaceae

Back 18

(1) Flagellar (H) - motility, protein in nature, and heat labile

(2) Capsular (K) - surface polysaccharides, heat labile

(3) Somatic (O) - associated with body of bacterial cell, polysaccharide side chain of the lipopolysaccharide in the outer membrane, heat stable, without film, nonswarming

Written like O111:H99:K2

Front 19

Virulence factors/toxins

Back 19

(1) Endotoxins: release of lipopolysaccharides (LPS) in outer membrane of gram negative bacteria, causes hypotension, shock, fever, intravascular coagulation, and/or death. Composed of: Lipid A, core polysaccharide, and "O" antigens. Lipid A is endotoxin component.

(2) Exotoxins: (into environment from bacteria) toxic proteins liberated from a bacterial cell into the surrounding environment, either heat labile or heat stable, can be produced by either gram- or gram+ organisms

(3) Enterotoxins: an exotoxin that acts on the intestinal tract, can be produced in food and ingested or produced by bacteria in intestine. Causes diarrhea, vomiting, can act directly on intestinal wall or can be picked up by bloodstream and act elsewhere.

Front 20

Salmonella species

Back 20

ENTEROBACTERIACEAE

(1) S. typhi: causes typhoid fever, characterized by prolonged fever, bacteremia, reticuloendothelial system involvement (liver/spleen), dissemination to multiple organs.

(2) All other species besides S. typhi: cause acute gastroenteritis/food poisoning characterized by vomiting/diarrhea, common outcome of poor sewer drainage/outhouses, taxonomy based on antigenic groups.

Front 21

Shigella characteristics and 4 species

Back 21

ENTEROBACTERIACEAE

(Dirty Fingers Bring Shigella)

Not part of normal microbiome

Low infective dose

Fecal-oral contact, flies, food, water, poor sanitation

All 4 species call dysentery

Can invade intestinal cell wall which causes mucusy, bloody stools.

(1) S. dysenteriae

(2) S. flexneri

(3) S. boydii

(4) S. sonnei

Front 22

Shiga Toxin-Producing E. coli (STEC)

Back 22

ENTEROBACTERIACEAE

Produces toxins identical to S. dysenteriae, range: mild diarrhea to hemorrhagic colitis, hemolytic uremic syndrome, E. coli O157:H7 is most common in US

Front 23

Yersinia species

Back 23

ENTEROBACTERIACEAE

Y. pestis: transmitted to humans by rodent fleas bite, bubonic or pneumonic, dogs are asymptomatic carriers, cats are symptomatic, both contagious to transmit primary pneumonic plague

Other Yersinia species:

Y. enterocolitica: is most commonly isolated, swine/dogs/cats, acute enteritis is most common infection

Y. pseudotuberculosis: primarily pathogenic to rodents/guinea pigs, clinical manifestations include septicemia accompanied by mesenteric lymphadenitis (similar presentation to appendicitis)

Front 24

Escherichia coli characteristics

Back 24

ENTEROBACTERIACEAE

•major facultative inhabitant of large intestine

•opportunistic: UTIs and wound infections, pneumonia, meningitis, septicemia

•travellers diarrhea

•very virulent

•weve been co-evolving for so long so at least 165 O antigens, 100 K antigens, and 50 H antigens

Front 25

Names of all common general of the family Enterobacteriaceae

Back 25

1. Citrobacter

2. Edwardsiella

3. Enterobacter

4. Escherichia

5. Klebsiella

6. Morganella

7. Proteus

8. Providencia

9. Salmonella

10. Serratia

11. Shigella

12. Yersinia

Front 26

Vibrio cholerae transmission, clinical manifestations, and therapy guidelines

Back 26

Hurricane Katrina I think you mean hurricane tortilla

•Transmission through food and water, seafood, very contagious

•Clinical manifestations: most are asymptomatic or have self limiting diarrhea, rice water stool, severe cases can produce watery diarrhea with water loss of 1 liter/hour

•Therapy: oral and IV rehydration, antibiotics decrease duration of disease/shedding of organism

Front 27

Transmission and disease of Vibrio parahaemolyticus:

Back 27

Transmission: raw fish, oysters, shrimp, crab, causes 50-70% of foodborne illness in Japan

Disease: acute gastroenteritis, most frequent in US, self limiting

Front 28

Transmission and disease of Vibrio vulnificus

Back 28

Transmission: oysters

Disease: very invasive, causes wound infections, septicemia, predisposing conditions are liver disease and increased serum iron

Front 29

Transmission and disease of Aeromonas hydrophila

Back 29

Transmission: fresh, brackish, or salt water, isolated from cold blooded animals, amphibians, reptiles, fish

Disease: self limiting diarrhea, wound infections

Front 30

Campylobacter jejuni transmission and disease

Back 30

Transmission: contaminated food, dairy products, water, in GI tract of animals

Disease: most common cause of bacterial gastroenteritis, bloody diarrhea, fever, severe abdominal pain, self limiting

Front 31

Helicobacter pylori transmission and disease

Back 31

Transmission: gastroenteritis, higher pH due to release of urease enzyme, peptic ulcer disease, gastric cancer risk factor

Front 32

Gram stain and unique characteristics of Vibrio

Back 32

Curbed, gram neg bacilli, halophiles (require or tolerate salt), oxidase positive, TCBS media

Front 33

Gram stain and characteristics of Aeromonas

Back 33

Non curved gram neg bacillia, no growth on TCBS, oxidase positive, nonhalophilic

Front 34

Gram stain and characteristics of Campylobacter

Back 34

Curved gram neg bacilli, oxidase positive, selective media, microaerophilic conditions

Front 35

Gram stain and characteristics of Helicobacter

Back 35

curved, gram neg bacilli