(LE4) Bacterial Pathogens Flashcards
What virulence factor is shared with all S. aureus strains?
Coagulase
- form a blood clot around bacteria
- important for furuncle and carbuncle
What complication is shown?
Scalded Skin Syndrome
- lysogenized exotoxin only found in one type of Staph as a result of transduction with a bacteriophage
- most common in newborns and infants
What is TSST-1
Can cause toxic shock syndrome
S/S: - sunburn-like rash
- relatively high fever
- Shock
What is enterotoxin?
Cause food-borne illness
What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts
Disease: staph infection
Pathogen: S. aureus
MOT: direct contact on skin
S/S: different forms based on entry points and virulence factors
- Furuncle (boil) inflammation filled with pus. Can move subcutaneously and become carbuncle
- Endocarditis: if it enters the bloodstream
Tx: Antibiotics
ETC: Food poisoning (heat stabile toxins, Staph is a halophile)
Describe different Streptococcus virulence factors
Dependent on portal of entry
- Hyularonidase and Collagenase: breaks down CT
- Protease: protein breakdown
- Pyrogen: Fever inducer
- Leukocidins: WBC breakdown
- Hemolysins: RBC breakdown
- Erythrogenic toxin: causes scarlet fever
- H protein: super antigen that creates immune complexes
What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts
Disease: strep throat
Pathogens: Streptococcus pyogenes (group A beta-hemolytic Strep)
MOT: Droplet (PoE: Upper respiratory tract)
S/S: sore throat, fever, dysphagia
Tx: antibiotics
What complication is pictured?
Scarlet fever
erythrogenic toxin
S/S: - sunburn-like rash, fever, strawberry tongue
- skin doesn’t blanche
What complications can occur post-Strep infections with M protein?
Rheumatic fever
- Ag-Ab complexes settle in joints and heart valves
- arthritic-like symptoms
Glomerulonephritis
- Ag-Ab complexes settle in kidney
- Inflamed kidneys
- may require dialysis or kidney transplant
What disease is shown?
Erysipelas - cutaneous strep infection
S/S: fever and rash with well-defined edges
Portal of Entry: hair follicle
What disease is shown?
Necrotizing Fasciitis - “flesh-eating” Streptococcus
Portal of Entry: minor cut/abrasion
S/S: Begins with furuncle and spread quickly (few days)
- Systemic infection: DIC
Tx: - Localized: surgery, amputation, antibiotics
Describe bacterial meningitis
Pathogen: Multiple
Portal of entry: Respiratory -> blood -> CSF. may be part of normal flora for some
S/S: - headache, stiff neck, high fever, ringing in ears
Tx: Broad-spectrum antibiotics
ETC: - occur in sporadic outbreaks
Dx: Lumbar puncture
- more severe than fungal or viral meningitis
What bacteria cause meningitis?
Streptococcus pneumoniae (G+C)
- most common in children and elderly
Neisseria meningitidis (G-C)
- most common in adolescents and young adults
- outbreaks
Haemophilus influenzae b (G-B)
- most common in 6mo-4yr
What disease is shown?
Disease: Tetanus
Pathogen: Clostridium tetani
Portal of Entry: Deep wound (anaerobic tissue) (spore in soil)
S/S: Spastic paralysis, fatal: diaphragm
Tx: vaccine, antitoxin, and antibiotics
ETC: - tetanus toxin inhibits ACh re-uptake (for muscle relaxation) at NMJ
What disease is shown?
Disease: Botulism
Pathogen: Clostridium botulinum
Portal of Entry: canned foods or needles (IV drug use)
S/S: Flaccid paralysis, fatal: diaphragm
Tx: Antitoxin
ETC: - botulism toxin inhibits ACh release at NMJ
What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts
Disease: Gas gangrene
Pathogen: Clostridium perfringens (soil-dwelling spore former)
PoE: Deep wounds
S/S: Gas bubble formation, Necrosis
Tx: Amputation, antibiotics (best early with wound)
ETC: before antibiotics, maggot therapy was used
What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts
Disease: Anthrax “woolsorter’s disease”
Pathogen: Bacillus anthracis (spore former)
Cutaneous: - PoE: wound
- S/S: Dark localized sore, potential septicemia (10-20% fatality)
Inhalation: - PoE: respiratory tract
- S/S: rapid onset pneumonia (100% fatal)
Tx: antibiotics
What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts
Disease: Septicemia
Pathogen: most often G- bacteria growing in blood
PoE: nosocomial infection
S/S: preceded by lymphangitis, broad symptoms, elevated WBCs, shock
Tx: antibiotics, anti-inflammatories
ETC: fast-moving, treatment difficult for G- bacteria
What disease is shown here? What causes this disease?
Disease: Endocarditis
Pathogen: Staphylococcus (acute; days-weeks), Streptococcus (Subacute; weeks-months)
PoE: Nosocomial bacteremia, dental work, poor nursing care
ETC: Most common with damaged heart valve (Rheumatic fever, congenital defect, other infections)
What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts
Disease: Plague
Pathogen: Yersinia pestis
Reservoir: rats, rodents. - Vector: Fleas
Bubonic plague: -S/S: buboes, high fever, sepsis, hemorrhaging
- ETC: 50% fatality (untreated). Veterinary problem
Pneumonic plague: - S/S: Rapid onset pneumonia
- Acute, 100% fatal
- Inhalation from bubonic patient
Tx: antibiotics
What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts
Disease: Lyme disease
Pathogen: Borrelia burgdorferi
Reservoir: mice, Vector - Deer tick
S/S: Bullseye rash at bite site, systemic granulomas, arthritis, neurological symptoms
Tx: antibiotics if caught early, vaccine (not very effective)
What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts
Disease: Diphtheria
Pathogen: Corynebacterium diptheriae (G+ uneven bacillus)
MOT: Droplet transmission (very contagious)
S/S: Gray pseudomembrane -> dyspnea
Tx: Antibiotics, antitoxin, DTaP vaccine
ETC: Lysogenized exotoxin: inhibits protein synthesis
What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts
Disease: Whooping cough (pertussis)
Pathogen: Bordetella pertussis
MOT: Droplet transmission (very contagious)
S/S: Chronic cough (1-6 weeks), can be fatal in young infants
Tx: antibiotics.
Vaccines: Old: inactivated, effective, side effects. New: TDaP, acellular, safe, less effective, frequent boosters
ETC: Exotoxin kills cilia in throat (cough to move mucus, difficult to inhale when coughing)
What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts
Disease: Hansen’s Disease (Leprosy)
Pathogen: Mycobacterium leprae (slow to grow/die. prefers cooler areas of body like skin and limbs)
PoE: Respiratory
Tuberculoid form: -milder
- S/S: raised lesions, loss of skin pigment, loss of sensation
- Good immune system
Lepromatous form: - more serious
- S/S: granulomas in skin and limbs, disfigurement, “lions face”(disfigurement of philtrum)
- immunocompromised
Tx: Years of antibiotics
ETC: Chronic condition (incubation period is 4-8 years)
Not infectious after 24 hours receiving treatment.
What disease is shown here? What causes this disease? Describe the mode of transmission, prevention and treatment, and interesting facts
Disease: Tuberculosis
Pathogen: Mycobacterium tuberculosis (slow to grow and die)
MOT: Droplet transmission (not very contagious, needs prolonged exposure to make it to alveoli)
Non-progressive TB: - grows inside alveolar macrophage, granulomas form, granuloma calcify to form tubercle. Tubercle contained without underlying disease. No symptoms, not contagious
Progressive TB: With underlying conditions (COPD, immunocompromization), tubercles break open and spread bacteria. Lung and BV damage -> bloody cough. Contagious
Disseminated TB: bacteria spreads to at least one other organ, “consumption”
Tx: 6 mo-2yrs Isoniazid compliance, BCG vaccine (minimal protection)
ETC: Multi-drug resistance
TB Skin test: type 4 immune reaction, if exposed Tc cells will swell area. Not specific if recent or previous exposure, or vaccine
Describe two types of diarrheal diseases
Infection: bacteria growing in the gut
- longer incubation period (Days)
- Shigella flexneri (bacterial dysentery)
- Vibrio cholerae (cholera)
- Salmonella (food poisoning)
- Tx: Antibiotics and Fluid resucitation
Intoxication: ingest toxin
- Shorter incubation period (hours)
- S. aureus enterotoxin
- Clostridium botulinum toxin
- Tx: Fluid resucitation and anti-toxins
What causes chlamydia, what are its symptoms, and how do you treat it?
Pathogen: Chlamydia trachomatis
-STD (confused with yeast infection)
S/S: mild: urethral irritation, thin discharge
Tx: Doxycycline
ETC: Untreated could cause PID
What causes gonorrhea, what are its symptoms, and how do you treat it?
Pathogen: Neisseria gonorrhoeae
- STD
S/S: more severe: burning w/ urination, thick discharge (green, odor)
Tx: Narrow-spectrum antibiotic, resistant to β-lactamase
What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts
Disease: Syphilis
Pathogen: Treponema pallidum (G- spirochete)
Primary stage: Chancre
Tx: antibiotics
Secondary stage: Rash
Tx: antibiotics
Tertiary stage: Can cross placenta, Neurosyphillis, Ocular syphilis (blindness), Otosyphilis (deafness)
Tx: none
