MID 2 - Lecture 11

Question 1

Diphtheria (toxin mediated disease)

Answer 1

Gram +, Rod, non spore, non motile, resistant to drying, respiratory
-Toxin mediated disease
AB toxin encoded by tox gene, inactivates elongation factor EF-2, blocks protein synthesis, cardic, kidney, nervous tissue destroyed

Question 2

AB Exotoxin

Answer 2

secreted by Diphtheria (and others), two domains connected by disulfide bond, B binds to host cell (endocy), acidic environment of endosome breaks bond, releases A domain into cytoplasm, domain travels in body

Question 3

Diphtheria (how presents in ppl)

Answer 3

> 30 yrs w/ weakened immunity, diagnosis = thick grey pseudomembrane in throat
-antibiotic therapy, immunization DTap vacc, antitoxin

Question 4

Tetanus

Answer 4

anaerobic, gram +, endospores (soil, dust, hospitals, feces), through skin wounds, produces tetanospasmin (in low O2) = 2nd deadliest toxin, tetX encodes for AB toxin, blocks GABA release, muscle spasms

Question 5

Tetanus (how presents in ppl)

Answer 5

tension/cramping (skeletal muscles, tight jaw), trismus (lockjaw), death = spasm of diaphragm and irm
-antibiotic therapy, DPT vaccine

Question 6

Pertussis (whooping cough - PTx)

Answer 6

droplet inhalation, colonizes respiratory tract cilia, toxins have toxic affects
- PTx is an AB toxin
A subunit = ADP-ribosyl transferase, ADP ribose added to Adenylate cyclase, stuck in active state, ATP converted to cAMP (continous), secretion of thick mucous (death of cilia)

Question 7

Pertussis (how presented in people)

Answer 7

7-14 day incubation, cold like symptoms, prolonged coughing sieges with inspiratory whoop, permanent immunity develops
-Bacterial culture, antibiotic therapy, DPT or Tdap acellular vaccine for older children/adults

Question 8

Meningitis (diff types)

Answer 8

inflammation of brain or spinal cord meninges, headache, fever, stiff neck, many causes (viral)
- Pneumococcal (pneumonia, ear and sinus infections)
-Meningococcal (teenagers, young adults, dorms, boarding school)
- Haemophilus influenzae serotype B (not cause of influenza)

Question 9

Meningitis (treatment)

Answer 9

s. penumoniae = vaccine, antibiotics
N. meningitidis = antibiotics, vaccine
H.influenzae = pneumonia and meningitis kill 3 mill worldwide/year, vaccine reduced to 1/100000

Question 10

Tuberculosis

Answer 10

Caused by mycobacterium tuberculosis (Mtb), M. Bovis, M. africanum
-transmission: droplet nuclei in resp tract, infected animals and products, dormant infection reactivate
-develops slowly
mycobacteria produces mycolic acid in cell wall (protective)
resistant to penetration of some antibiotics, and dehydration

Question 11

Infection of MtB (in person)

Answer 11

inhalation (10 cells enough), fever, fatigue, night sweats, weight loss, cough
-diagnosis
Observation of acid-fast bacteria, chest xray, mantoux, tuberculin skin test, DNA based tests

Question 12

TB course of disease

Answer 12

lung macrophages phagocytosed to M tuberculosis often die in attempt to kill bacteria
-form granulomas
composed of bacteria macrophages, t cells, and human proteins, can become calcified, forms tubercles

Question 13

Lyme disease

Answer 13

most common tick-borne disease in US, gram -, caused by borrelia burgdorferi, b.garinii, b.afzelii, spirochete

Question 14

Lyme transmission by ticks

Answer 14

transmitted from animal reservoirs by ticks (deer, field mice, woodrats), complex, three stages (localized, disseminated, late stage)

Question 15

Stages of lyme disease

Answer 15

localized: 7-10 days after infection, expanding, ring shaped, flu
disseeminated: weeks or months after infection, neuro abnormalities, heart inflammed, arthritis
Late stage: years later, demyelination of neurons, behavior, symptoms like alzheimers and MS

Question 16

Lyme (diagnosis)

Answer 16

serological testing, isolation of spirochete from patient, detection of borrelia DNA (PCR)
treatment: antibiotic therapy early, tick control, education/ personal protection

Question 17

Gastroenteritis

Answer 17

inflammation of stomach and intestinal lining

Question 18

Food poisioning

Answer 18

food is source of pathogen

Question 19

Food borne infection

Answer 19

pathogen must colonize host

Question 20

food intoxication

Answer 20

ingestion of toxin (enterotoxins - disrupts intestinal mucosa causing nausea, vomiting, diarrhea)

Question 21

Peptic Ulcer disease

Answer 21

gram -, caused by helicobacter pylori

Colonizes gastric mucus-secreting cells, produces urease (increase pH), releases toxins that damage epithelisal mucosal cells), 50 % affected

Question 22

H. pylori disease

Answer 22

colonzies gastric mucus secreting cells, beneath gastric mucosa by aid of surface fimbriae, produces ureases, hydrolyze ammonia and provides local alkaline environment

Question 23

H.pylori disease (diagnosis)

Answer 23

culture biopsy speciments, examine stained biopsies, serological testing, urea breath test, tests for ammonia in urine, detection of urease activity in biopsies
treatment: combination of drugs to decrease stomach acid and antibiotics to kill bacteria

Question 24

Cholera

Answer 24

ingesting food or water contaminated by fecal matter from carriers, adheres to intestinal mucosa of small intestine and secrete toxin choleragen (AB toxin), presence of toxin results in major loss of water and electrolytes

Question 25

cholera (diagnosis)

Answer 25

culture from species with subsequent identification by agglutintion rxns
treatment: oral rehydration, antibiotic therapy, sanitation of water supply

Question 26

Salmonellosis

Answer 26

gram -, non spore forming rods, in intestinal tracts, contaminated foods (beef, poultry, egg products, water)
abdominal pain, cramps, diarrhea, nausea, vomiting, fever
treatment: fluid, electrolytes, food handled carefully

Question 27

Typhoid fever

Answer 27

salmonella enterica subspecies, gram - rod, AB toxin, food or water by feces, infection from small intest to lymphoid tissue, blood, liver, gallbladder
Fever, headache, abdominal pain, anorexia, malaise
-in carriers bacteria grow in gallbladder, reach intestine through bile duct

Question 28

Typhoid (diagnosis)

Answer 28

demonstration of typhoid bacilli in blood, urine, or stools, serology
treatment: antibiotics, vaccine, food handling, purification of water, isolate patients

Question 29

Dental disease

Answer 29

various odontopathogens, hard enamel, neg charged surface repel bacteria, formation of dental plaque = pathogens producing acids

Question 30

Dental plaque

Answer 30

acquired enamel pellicle
colonized by various bacterial species to form, streptococcus mutans attach produce polysaccharide cement from sucrose,
lactic acid production: demineralize enamel, breached enamel = bacterial entry

Question 31

Dental decay

Answer 31

demineralization/remineralization cycle
production of acids leads to release of calcium and phosphate ions from enamel followed by remineralization
Demin > remin = caries
treatment: no drugs, good dental hygiene, minimize ingestion of sucrose