MCB Exam 3

Question 1

Neisseria

Answer 1

The only gram negative cocci, in pairs, so also called diplococci

Question 2

N. gonorrhea

Answer 2

• causes gonorrhea. Transmitted by direct contact during sexual activity
  ​-Infects mucous membranes of urethra, vagina, anus, mouth and pharynx
  ​-Symptoms: men – burning during urination
  ​​Women – often asymptomatic
  -Can infect infant eyes during birth

Question 3

N. meningitidis

Answer 3

-About 40% of humans have this in the pharynx without symptoms (carriers). Transmitted by droplets or on fomites
-Symptoms: Stiff neck severe headache, fever, and general neurological effects and eventual loss of consciousness
-Very rapid illness. Diagnosed by cloudy fluid from lumbar puncture

Question 4

Rods Enterobacteriaceae (Enterics)

Answer 4

These are bacteria
-that Are short,
-Gram negative rods
-​Ferment glucose (and make acid and gas from it)
​-Don’t form endospores
​Are oxidase negative

Question 5

ColiformS

Answer 5

Enterics that also ferment lactose

Question 6

E. coli

Answer 6

usually causes gastroenteritis called traveller’s diarrhea (O157:H7 strain from undercooked ground beef causes hemolytic uremic syndrome that damages the kidneys). Most common cause of non-gonococcus urinary tract infections.

Question 7

Klebsiella

Answer 7

pneumonia is a common cause of pneumonia

Question 8

Serratia marcescens

Answer 8

has a bright red pigment called prodigiosin and is mainly a problem for hospital patients, where it is a major cause of hospital-acquired infections

Question 9

Non-coliforms

Answer 9

enterics that don’t ferment lactose

Question 10

Proteus

Answer 10

Swarms across plate surface often forming a bull’s eye pattern. Second leading cause of non-gonococcal urinary tract infections and can sometimes cause kidney stones

Question 11

True pathogenic enterics

Answer 11

not normal in intestines

Question 12

Salmonella

Answer 12

spread in contaminated water (oral-fecal). Causes diarrhea with fever, nausea and vomiting, can enter intestinal cells - sometimes cause bacteremia (blood infections).

Question 13

Salmonella typhi

Answer 13

causes typhoid fever. Spread oral-fecal from people with active typhoid fever or from asymptomatic carries where it survives in the gall baldder.

Question 14

Shigella

Answer 14

Similar to Salmonella but causes bloody diarrhea (bacterial dysentery). Enter intestinal cell cytoplasm by endocytosis; move through host cell cytoplasm by actin rockets similarly to Listeria (a gram positive). Rarely causes blood infection.

Question 15

Yersinia3

Answer 15

Species that cause human infections. Two cause gastroenteritis like Salmonella.

Question 16

Yersinia pestis

Answer 16

causes black plague. Can spread from rodents (rats, prairie dogs) to humans by fleas, then infects lymph nodes to cause buboes and can also cause gangrene. Can also infect lungs to cause pneumonia then spread to others by coughing. Can also be acquired by touching fluid from buboes.

Question 17

Pasteurellaceae

Answer 17

These are gram negative rods that are not enterics because they are oxidase positive.

Question 18

Pasteurella

Answer 18

spreads from animals (especially cats and dogs) by saliva, especially from scratches or bites. Mostly causes swollen lymph nodes near the bite or scratch site and mild fever.

Question 19

Haemophilus

Answer 19

Very short rods that are fastidious (requiring Hema and NAD+ in their medium). Live in the pharynx of many people. H. influenzae is a common cause of meningitis in young children.

Question 20

Bartonella

Answer 20

Spread by sandflies (Bartonellosis) , Lice (Trench fever) or cat scratches (Cat scratch fever) – usually causes localized swollen lymph nodes or tissues at the site of entry.

Question 21

Brucella

Answer 21

Zoonotic disease that spread from animals to humans by contact or from drinking unpasteurized milk. Flu-like symptoms with a fluctuating fever. One species causes Malta fever.

Question 22

Bordetella

Answer 22

B. pertussis inly lives in human pharynx. Adheres to the epithelial cells of the trachea and produces toxins that stop cilia motion and kill cells. Causes whooping cough so it spreads via coughed droplets.

Question 23

Burkholderia

Answer 23

Lives in soil but can infect the mucous in the lungs of cystic fibrosis patients.

Question 24

Pseudomona

Answer 24

Main pathogenic species is P. aeruginosa – it lives in soil, but it is an opportunistic pathogen. Can infect the mucous in the lungs of cystic fibrosis patients, also attaches to catheters and infects bandages of open wounds, turning them green.

Question 25

Moraxella

Answer 25

another soil organism that is an opportunistic cause of ear and upper respiratory tract infections.

Question 26

Acinetobacter

Answer 26

another soil organism that is an opportunistic cause of respiratory, urinary and central nervous system (meningitis) infections.

Question 27

Francisella

Answer 27

infects small animals, causes rabbit fever in human, Acquired in many ways (contact. Inhalation, swallowing, through eyes, cuts and maybe even unbroken skin). Rabbit fever is usually mild, but it only takes a few bacteria to cause an infection (about 10).

Question 28

Legionella

Answer 28

Lives in amoebas in warm water and passes to people via inhalation when it gets into the air (usually from aerosol air conditioning cooling tanks). Lives inside of white blood cells in the lungs, and can’t grow outside of them. Causes pneumonia. Can only grow in the lab on charcoal agar.

Question 29

Coxiella

Answer 29

Causes Q fever and can only grow inside of other cells (obligate intracellular parasite), usually white blood cells. Infective bodies can move between hosts (humans, mice, other small animals) through tick bites or drinking unpasteurized milk or inhalation of dried feces dust.

Question 30

Rickettesia

Answer 30

Obligate intracellular pathogens with a cell wall. All damage blood vessels and cause rashes in addition to flu-like symptoms.

Question 31

R. prowazekii

Answer 31

causes epidemic typhus (and can recur later as Brill-Zinsser, spread by lice feces. In US the main reservoir is flying squirrels.

Question 32

R. typhi

Answer 32

spread from rodents to people by fleas

Question 33

R. rickettsii

Answer 33

causes Rocky Mountain spotted fever. Transmitted from rodents to people by ticks.

Question 34

Chlamydia

Answer 34

Obligate intracellular pathogen with no cell wall. Spreads between people vis contactor inhalation. Have a complex life cycle. In cells the active, growing bacteria live in the endocytic vesicles and are called reticulate bodies. They become inactive elementary bodies that are released and survive until the can attach to a new host cell and infect it.

Question 35

C. trachomatis

Answer 35

infects mucous membranes of the urogenital tract and eyes (including newborns during birth if in the mother’s birth canal). Causes the STI Chlamydia (called lymphogranyloma venerium when the inguinal lymph nodes become buboes) and trachomatis (in the eyes). Causes the eyelids to curl in and can lead to blindness.

Question 36

Chlamydiophila pneumoniae

Answer 36

inhaled from coughed droplets and causes mild pneumonia that resembles Mycoplasma pneumonia.

Question 37

Chlamydiophila psittaci

Answer 37

causes pneumonia when inhaled from bird mucous and dried feces.

Question 38

Spirochetes

Answer 38

very long flexible spirals that move in a corkscrew motion using axial filaments (bundles of flagella bent back along the cell axis and between the cell membrane and the outer membrane). This allows them to move in very viscous medium.

Question 39

Treponema pallidum

Answer 39

causes syphilis, pinta, yaws and bejel. Very thin so difficult to see in the microscope.

Question 40

Borrelia burgdorferi

Answer 40

causes Lyme disease that is spread from animals (usually deer) by tick bites. Often has a bull’s eye rash at tick bite site. If untreated can cause joint and neurological problems years later.

Question 41

Borrelia recurrentis

Answer 41

causes relapsing fever. The bacteria switch surface antigens repeatedly to escape the immune responses of the body. Usually spread by tick or louse bites.

Question 42

Leptospira

Answer 42

spread from animals to humans via urine either in contaminated water or when animals are contacted (petting, litter boxes) or urine-contaminated soil. Infect kidney of animals and humans and can cause kidney damage.

Question 43

Vibrio

Answer 43

hort, curved, comma-shaped rods. Oxidase positive and very motile with a single polar flagellum. Most prefer salty water (ocean or brackish)

Question 44

Vibrio cholera

Answer 44

the only vibrio that lives in fresh water, Spread oral-fecal when diarrhea enters water. Causes severe diarrhea that can be fatal (60% if untreated) and looks like boiled rice (rice-water diarrhea).

Question 45

V. parahemolyticus

Answer 45

cholera-like diarrhea that is rarely fatal when eating undercooked shellfish

Question 46

V. vulnificus

Answer 46

Like V. parahemolyticus (diarrhea from raw oysters, etc.) but much more deadly. Can also enter from ocean water into cuts and cause deadly necrotizing fasciitis.

Question 47

Campylobacter jejuni

Answer 47

Causes food poisoning that can last a week when the bacteria live in the intestines. A leading cause of food poisoning, often unreported. Acquired from raw chicken, unpasteurized milk when contaminated with the bacteria from poultry. Spiral cells.

Question 48

Helicobacter pylori

Answer 48

spread oral fecal. The bacteria live in the stomach between the gastric epithelia cells and the mucous above the cells. Attack the cells, killing them and causing a gastric ulcer. Spiral cells.