Lecture #21

Question 1

Filamentous Hemagglutin

Answer 1

Aids in attachment and prevents phagocytes from responding to infection

Question 2

Pertussis Toxin

Answer 2

Aids in attachment and causes increased mucus production

Question 3

Tracheal Cytotoxin

Answer 3

Inhibits the movement of cilia on ciliated respiratory cells

Question 4

Symptoms of Pertussis

Answer 4

Vomiting after cough, subjunctival hemorrhages, rib fractures, incontinence, hernias, facial hematomas

Question 5

Treatment of Pertussis

Answer 5

Manage signs and symptoms

Antibacterial drugs have little effect (unless given early)

Question 6

Prevention of Pertussis

Answer 6

Immunization with the DTaP vaccine

Cases in the US are increasing due to a refusal by some parents to have their children immunized

Question 7

Pseudomonas aeruginosa

Answer 7

Gram- negative, rod, motile, aerobic

Can live in any moist environment
Capable of growing in distiller water

From the Greek: pseudes “false” and monas “single unit”

NOT part of a human’s normal microbiota

Question 8

Pseudomonas aeruginosa Disease

Answer 8

Can colonize almost any organ or tissue
Results in various diseases

Opportunistic pathogen of immunocomprised patients, burn patients, and cystic fibrosis patients

Attachment to human cells via
Capsule (shields from phagocytosis)
Numerous Fimbrae
Adhesins

Numerous toxins inhibit protein synthesis in eukaryotic cells

Question 9

Diagnosis of Pseudomonas aeruginosa

Answer 9

Catalase positive

Beta-hemolytic on blood agar

Produces PYOCYANIN
green in color
Grape-like odor

Question 10

Treatment of Pseudomonas aeruginosa

Answer 10

Resistant to many antibiotics

Quinolone antibiotics still seem to be effective

Question 11

Prevention of Pseudomonas aeruginosa

Answer 11

Maintain a sanitary environment

Hand washing

Question 12

Vibrio (genus)

Answer 12

Gram-negative, motile, oxidase positive, curved rods

All species are SALT-TOLERANT

Question 13

Vibrio cholera

Answer 13

Most common species to infect humans

Humans become infected with V. cholera by ingesting contaminated food or water

Found most often in communities with poor sewage and water treatment

Some V. cholera infections are asymptomatic or cause only mild diarrhea

Question 14

Cholera

Answer 14

Severe abrupt watery diarrhea and vomiting
RICE-WATER STOOL is a characteristic

Results in severe fluid and electrolyte loss

Can progress to coma or death

Strain O1 EI Tor is very virulent and widespread

Question 15

Cholera toxin

Answer 15

Composed of two subunits: A and B

B binds to epithelial cells

A is cleaved and a small portion (A1) enters the cell

Question 16

Cholera Diagnosis

Answer 16

Usually based on the characteristic rice-water stool

Isolate the organism from stool samples

Question 17

Treatment of Cholera

Answer 17

Fluid and electrolyte replacement

Antimicrobial drugs are not effective because they are lost in the watery stool

Question 18

Chlamydia (genus)

Answer 18

Do not have cell walls
Have two membranes but without any
peptidoglycan between them

Grow and multiply only within the phagosome of host cells (OBLIGATE INTRACELLULAR PARASITE)

Have a unique developmental cycle involving 2 forms
Both forms can occur within the
phagosomes of a host cell

Question 19

Bordetella pertussis

Answer 19

Gram-negative, non-motile, short rods, aerobic

Humans are the only known host

Causes the disease PERTUSSIS (whooping cough)

Question 20

Chlamydia trachomatis

Answer 20

Only two known hosts
One strain infects mice
All others infect humans

Infect the conjunctiva and various mucous membranes

Enters the body through abrasions and lacerations

Two clinically relevant strain types
TRACHOMA strains
LGV strains

Question 21

Trachoma

Answer 21

Bacteria multiply in conjunctival cells resulting in scarring

Scarring causes eyelashes to turn inward and abrade the eye

Infects children at birth

Transmitted by flies

Endemic in crowded, poor communities with poor hygiene and inadequate sanitation

500 million cases worldwide
8 million visually impaired individuals

Question 22

Treatment of chlamydia Trachoma

Answer 22

Prompt treatment with antibiotics and surgical correction of the eyelid deformities

Prevention of reinfection (hygiene)

Question 23

Chlamydia (LGV)

Answer 23

Caused by trachomatis LGV strain

The most common STD in the U.S
Can infect children at birth

-Initially a small, painless lesions around the
genitals
-Painful urination/intercourse discharges,
inflammation
-Easily spread to the eyes

LYMPHOGRANULOMA VENEREUM- may progress to the lymph nodes in the groin producing swollen, painful buboes

1-4 million new cases each year in the US
More common in 3rd world countries
90 million new cases each year

Question 24

Treatment of chlamydia (LGV)

Answer 24

Antibiotics are effective

Question 25

Prevention of chlamydia (LGV)

Answer 25

Abstinence and safe sex

Question 26

STD’s and Diagnosis

Answer 26

Much of the increase is artificial
Increased and improved testing

Cultural methods vs. genetic testing (urine, self-swabbing)

Medical community now recognizes over half infections in females remain asymptomatic

Some of the increase is real, due to treatment
Undesirable outcome of treatment: Re-
infection

Normalized for improved testing, infections (re-infections) still likely increasing at 5-10% per annum