BIO205 Topic 7 Chapter 24-27

Dental Caries, E. coli Gastroenteritis, Typhoid Fever, HSV-1, E. coli Pathovars, Subacute Bacterial Endocarditis, Plague, Mono, Malaria, P. Meningitis, M. Meningitis, H. influ. Meningitis, Hansen's Disease, Botulism, Rabies, TSE, UTI, Gonorrhea, Syphilis, HIV/AIDS

Causative agent of Dental Caries

Streptococcus mutants; lactic acid (fermentation); glucans (bioflims)

Symptoms of Dental Caries

Enamel damage, discoloration, roughness, tooth may break, severe throbbing pain

Pathogenesis of Dental Caries

Pellicle → plaque; acid dissolves enamel; glucans essential

Epidemiology of Dental Caries

600+ oral bacteria; anaerobes → halitosis

Treatment/prevention of Dental Caries

Drilling/filling; reduce sucrose; fluoride; brushing/flossing

Causative agent of E. coli Gastroenteritis

Escherichia coli (Gram-negative rod)

Symptoms of E. coli Gastroenteritis

Watery diarrhea; dysentery; HUS (strain-dependent)

Pathogenesis of E. coli gastroenteritis

six pathovars: EPEC, ETC, EHEC/STEC, EIEC. EAEC, DAEC

Epidemiology of E. coli gastroenteritis

fecal-oral; contaminated food/water; traveler’s diarrhea

Treatment for E. coli Gastroenteritis

Most cases self-limiting; fluid replacement; avoid antibiotics in STEC

Prevention of E. coli Gastroenteritis

handwashing; pasteurization; proper cooking; bismuth ((traveler’s diarrhea)

Causative agent of Typhoid Fever

Salmonella enterica serotype Typhi

Symptoms of Typhoid Fever

fever, headache, constipation, abdominal pain, intestinal rupture/shock

Pathogenesis of Typhoid Fever

invades intestinal epithelium; survives in macrophages; systemic spread

Epidemiology of Typhoid Fever

human-only reservoir; fecal-oral; carriers (gallbladder)

Treatment/Prevention of Typhoid Fever

Antibiotics, typhoid vaccine, avoid risky food/water

Causative agent of HSV-1

herpes Simplex virus type 1 (oral herpes)

Symptoms of HSV-1

cold sores; latent in trigeminal ganglion; recurrences

Pathogenesis of HSV-1

Lytic epithelial infection → latent in nerves → reactivation

Epidemiology of HSV-1

Spread by saliva, kissing shared item

Treatment/prevention of HSV-1

Acyclovir reduces outbreaks; avoid contact during active lesions, no cure

List of E. coli pathovars

1)    E. coli HUS

2)    Diffusely adhering E. coli (DAEC)

3)    Enteroaggregative E. coli (EAEC)

4)    Enterotoxigenic E. coli (ETEC)

5)    Enteroinvasive E. coli (EIEC)

6)    Shiga toxin-producing E. coli (STEC)

7)    E. Coli 0157:H7

Why aren’t antibiotics helpful in intestinal infections?

viral/toxin-mediated; prolong illness; disrupt microbiota; increase C. diff risk

Causative agent of Subacute Bacterial Endocarditis (SBE)

Viridans streptococci; Staph epidermidis

symptoms of SBE

fatigue, slight fever, slow energy loss, stroke

Pathogenesis of SBE

bacteria enter blood → trapped in clots → biofilm → emboli

Epidemiology of SBE

heart valve defects; IV drug use; catheters; artificial valves

Treatment/Prevention of SBE

Long-term antibiotics; replace valves; prophylaxis

Causative agent of Plague

Versinia pestis

Symptoms of Plague

bubonic (buboes, fever, shock); pneumonic (cough, blood); septicemic (shock, bleeding)

pathogenesis of plague

flea biofilm block → regurgitation; macrophage survival; endotoxin; droplet spread

epidemiology of plague

flea-rodent cycle; Western U.S.; bioterrorism; droplets

treatment/prevention of plague

antibiotics early; rat control; insecticides; tetracycline prophylaxis

Why is it that there is an outbreak of plague in crowded cities?

Fleas main reservoir & rodents hosts·

Causative agent of Infectious Mononucleosis

Epstein-Barr Virus (EBV)

Symptoms of Mono

fever, sore throat with pus, fatigue, enlarged spleen/lymph nodes

Epidemiology of Mono

spread by saliva, EBV shed 18 months; most adults (90-95%) infected

Treatment/prevention of Mono

No vaccine; antivirals for productive infection; avoid saliva sharing (kissing)

Causative agent of Malaria

Plasmodium spp.; female Anopheles mosquito

symptoms of malaria

flu-like: paroxysms (cold → hot → wet); cycles every 24-48 hours

pathogenesis of malaria

sporozoites → liver → merozoites → RBCs; RBC rupture; capillary blockage

Epidemiology of Malaria

tropical regions; mosquitoes; transfusions; IV drug use; sickle cell protection

treatment/prevention of malaria

ACT therapy; bed nets; DDT; eliminate standing water

Causative agent of Pneumococcal meningitis

Streptococcus pneumoniae

symptoms of P. meningitis

cold-like → severe headache; fever; stiff neck; nausea/vomiting

pathogenesis of P. meningitis

capsule; binds meningeal cells; fluid accumulation; clots → tissue death

Epidemiology of P. Meningitis

droplets; high fatality in adults/elderly

treatment/prevention of P. Meningitis

penicillin/cephalosporins; vaccine

Causative agent of Meningococcal meningitis

neisseria meningitidis

Symptoms of Meningococcal M.

petechiae; fever; stiff neck; endotoxic shock

Pathogenesis of Meningcoccocal M.

inhaled → pili attachment → bloodstream; endotoxin shock

Epidemiology of Meningococcal M.

droplets; asymptomatic carriers

treatment/prevention of Meningococcal M.

penicillin/ceftriaxone; vaccines

Causative agent of Haemophilus influenzae Meingitis (Hib meningitis)

Haemophilus influenzae type b

symptoms of Hib meningitis

mild cold → severe headache; fever; vomiting; bulging fontanelle

pathogenesis of Hib meningitis

encapsulated strains; attach via pili; type b most severe

epidemiology of Hib meningitis

droplets; healthy adults carriers

treatment/prevention of Hib meningitis

cefotaxime/ceftriaxone; Hib vaccine

Causative agent of Hansen’s Disease (leprosy)

Mycobacterium leprae

Symptoms of Leprosy - Hansen’s

pigmentation changes; numbness; muscle wasting; deformities

pathogenesis of leprosy

grows in macrophages/nerves; tuberculoid (limites); lepromatous (contagious)

epidemiology of leprosy

nasal secretions; prolonged contact

treatment/prevention of leprosy

WHO multidrug therapy; no vaccine

Causative agent of Botulism

Clostridium botulinum

Symptoms of Botulism

12-36 hrs; dizziness; dry mouth; blurred vision; flaccid paralysis

pathogenesis of botulism

A-B toxin blocks acetylcholine release → paralysis

epidemiology of botulism

soil; home-canned foods; infant botulism (spores in honey); wound botulism

Treatment/prevention of Botulism

IV antitoxin; respiratory support; avoid honey in infants

Causative agent of Rabies

Rabies virus (rhabdovirus)

symptoms of rabies

fever; tingling; agitation; hallucinations; hydrophobia; coma (severe)

pathogenesis of rabies

replicates at bite → brain; Negri bodies; spread to organs

Epidemiology of rabies

bite of rabid animal; bats, raccoons, skunks, foxes

treatment/prevention of rabies

wash wound; immune globulin; vaccine; vaccinate pets

Causative agent of TSE (Transmissible Spongiform Encephalopathy)

Prions

Symptoms of TSE

behavioral changes; memory loss; muscle jerks; fatal in 1 year

pathogenesis of TSE

PrP (Prion Proteins) misfolding → neuron death → spongy death

Epidemiology of TSE

linked to mad cow disease

Treatment/prevention of TSE

no treatment; always fatal

Meningitis

inflammation of meninges

meningococcus

Neisseria meingitidis

Tuberculoid leprosy

limited, non-contagious form

hydrophobia

painful swallowing spasms in rabies

infant botulism

botulism from ingesting spores (honey)

Causative agent of Bacterial Cystitis (UTI)

Uropathogeneic E. coli (UPEC); other intestinal bacteria

Symptoms of UTI

burning urination; cloudy/bloody urine; odor; suprapubic pain

pathogenesis of UTI

ascend urethra; UPEC fimbriae; IBC formation

epidemiology of UTI

30% of women; short urethra; sex; birth control; catheters

Treatment/prevention of UTI

short antimicrobials; urinate after sex; wipe front-to-back

causative agent of Gonorrhea

Neisseria gonorrhoeae

symptoms of gonorrhea

painful urination; pus discharge; ectopic pregnancy; ophthalmia neonatorum

pathogenesis of gonorrhea

fimbriae + Opa proteins attach to non-ciliated epithelial cells

epidemiology of gonorrhea

sexual transmission; mother → baby

treatment/prevention for gonorrhea

cephalosporins; no vaccine; newborn eye prophylaxis

causative agent for syphilis

Treponema pallidum

Pathogenesis (types) of Syphilis

Primary (initial infection at entry site), secondary (systemic spread), latent (organism persists w/o symptoms), tertiary (chronic inflammatory damage) & congenital (crosses placenta)

Primary syphilis

chancre; highly infectious; heals 3-6 weeks

secondary syphilis

rash (palms/soles); mucous patches; fever; most infectious

latent syphilis

no symptoms; 25% recover; 25% stay latent