ch 21 micro
Scarlett fever
-systematic toxin from bacteriophage -high fever, rash, 95% mortality in early 20th century
Most common places for infectious agents to gain access to the body in the LOWER RESPIRATORY TRACT:
-trachea -bronchi -bronchioles -lungs -alveoli
Diptheria - corynebacterium diptheriae prevention?
DTaP vaccine 1. diptheria 2. tetanus 3. Pertussis
Pharyngitis - viruses treatment?
symptom relief only
Sore throat (caused by?)
Pharyngitis
Acute Otitis Media/Ear infection: Streptococcus pneumonaie Prevention?
Pneumococcal conjugate vaccine (heptavalent)
Common cold (caused by?)
Rhinitis
Pharyngitis - bacterias/viruses/fungi?
S. pyogenes, Fusobacterium necrophorum, viruses
Glomerulonephritis
-kidney damage due to antigen-antibody deposits in glomeruli
Most common places for infectious agents to gain access to the body in the UPPER RESPIRATORY TRACT:
-mouth -nose -nasal cavity -sinuses -pharynx -epiglottis -larynx
Rheumatic fever
-secondary infection -joint inflammation -heart valve damage
Diptheria symptoms/signs
-initially in URT -Sore throat, lack of appetite, low-grade fever -swelling blocking airway -Mycarditis (heart) and neuritis (nerves) can result from exotoxin
Normal biota of respiratory tract fast facts
-Generally limited to upper.. -Gram Pos. is very common (strep & staph) -Disease causing bacteria are present as normal biota; can cause disease if their host becomes immunocompromised or if transferred to other hosts -normal biota perform microbial antagonism
Sinusitis/Sinus infection
-Inflammation of sinuses -Caused by allergies, infections, or by structural issues -Generally follows common cold -Symptoms: nasal congestion, pressure above nose or in the forehead, feeling of headache or toothache, facial swelling/tenderness -green/yellow opaque discharge = bacterial infection -clear discharge, watery/itchy eyes = allergies -smokers are more susceptible
Anatomical defenses of the respiratory system
-Nasal hair: traps particles -Cilia: propels particles upward and out of the respiratory tract -Mucus: traps particles -Involuntary responses remove them from the respiratory system by: coughing, sneezing, swallowing
S. pyogenes complications
-Necrotizing fasciitis -Scarlet fever -Rheumatic fever -Glomerulonephritis
Rhinitis/Common Cold
-Rhinovirus -Also coronaviruses & adenoviruses -Symptoms: sneezing, scratchy throat, runny nose (rhinorrhea) -Symptoms due to immune response to viral infection, increased mucus secretion, swelling and inflammation of nasal mucosa -Symptoms 2-3 days after infection -Generally no fever -Secondary bacterial infection common -No vaccine -Transmission: respiratory droplets & fomites -Prevention: frequent handwashing, covering mouth/nose during sneezing and coughing -Treat symptoms w/ antihistamines
Normal biota of respiratory system:
-Strep. pyogenes -Haemophilus influenzae -Strep. pneumoniae -Neisseria meningitidis -Staph. aureus
Pharyngitis - S. pyogenes Virulence factors?
-Surface antigens toxins and enzymes -Polysaccharides prevent digestion -Spikey M protein prevents phagocytosis -capsule provides adherence -Secrete streptolysins -Erythogenic toxin: causes red rash and fever in scarlet fever
Streptococcus pyogenes
-causes strep throat -streptococcal pharyngitis -Lancefield group A -Beta-hemolytic
2nd & 3rd Line of Defenses in Respiratory System
-complement action in the lungs -increased levels of cytokines and antimicrobial peptides -macrophages in alveoli of lungs and tonsils -Secretory IgA against specific pathogens found in mucus secretions -Normal flora defend host by microbial antagonism
Diptheria
-corynebacterium diptheriae -Gram positive club shaped bacillus -toxigenic disease caused by lysogenic phage -pseudomembrane formed on tonsils and pharynx (bacterial cells, fibrin, lymphocytes, & dead tissue cells)
Diptheria - corynebacterium diptheriae common modes of transmission?
-droplet contact -direct or indirect contact with contaminated fomites
Pharyngitis
-inflammation of the throat -reddened mucosa, swollen tonsils, sometimes white packets of inflammatory products -mucous membranes may swell affecting speech/swallowing -incubation period 2-5 days
Sinusitis - viruses 1. Common modes of transmission? 2. Culture/diagnosis? 3. Prevention? 4. Treatment? 5. Distinctive features?
1. direct and indirect contact 2. culture not performed, diagnosis based on clinical presentation 3. hygiene 4. none 5. viral and bacterial much more common than fungal
Sinusitis - various bacteria 1. Common modes of transmission? 2. Culture/diagnosis? 3. Treatment? 4. Distinctive features? 5. Epidemiological factors
1. endogenous (opportunism) 2. culture not performed, diagnosis based on clinical presentation, occasionally X-rays or other imaging technique used. 3. Broad spectrum antibiotics or none 4. viral and bacterial much more common than fungal 5. Very common in US
Sinusitis - various fungi 1. Common modes of transmission? 2. Culture/diagnosis? 3. Treatment? 4. Distinctive features? 5. Epidemiological factors
1. introduction by trauma or opportunistic overgrowth 2. culture not performed, diagnosis based on clinical presentation, occasionally X-rays or other imaging technique used. 3. Physical removal of fungus or antifungals used in severe cases 4. Suspect in immunocompromised patients 5. SE & SW united states, India, N. Africa, Middle east
Pharyngitis - S. pyogenes Culture/diagnosis
Beta-hemolytic on blood agar, sensitive to bacitracin, rapid antigen tests
Ear infection (caused by?)
Actute Otitis Media
Diptheria - corynebacterium diptheriae treatment?
Antitoxin plus penicillin or erythromycin
Acute Otitis Media/Ear infection: Haemophilus influenzae Virulence factor?
Capsule, fimbriae
Acute Otitis Media/Ear infection: Streptococcus pneumonaie Virulence factors?
Capsule, hemolysin
Acute Otitis Media/Ear infection: Haemophilus influenzae common mode of transmission?
Endogenous
Acute Otitis Media/Ear infection: Streptococcus pneumonaie Mode of transmission?
Endogenous (may follow URT infection)
Diptheria - corynebacterium diptheriae Virulence factors?
Exotoxin: diphtheria toxin
Pharyngitis causative agent?
Fusobacterium necrophorum
Acute Otitis Media/Ear infection: Haemophilus influenzae Prevention?
Hib vaccine
Sinus infection (caused by?)
Sinusitis
Acute Otitis Media/Ear infection: Streptococcus pneumonaie Culture/diagnosis?
Usually relies on clinical symptoms and failure to resolve within 72 hours
Acute Otitis Media/Ear infection: Haemophilus influenzae Treatment?
Wait for resolution; if needed take amoxicillin or amoxicillin + clavulanate or cefuroxime
Acute Otitis Media/Ear infection: Streptococcus pneumonaie Treatment?
Wait for resolution; if needed take amoxicillin or amoxicillin + clavulanate or cefuroxime
Pharyngitis - Fusobacterium necrophorum distinctive features?
adolescents/young adults, neck swelling, infections spreading to cardio system or deeper tissues
Pharyngitis - viruses common modes of transmission?
all forms of contact
Pharyngitis - S. pyogenes common modes of transmission?
droplet or direct contact
Pharyngitis - Fusobacterium necrophorum culture/diagnosis?
growth on anaerobic agar
Pharyngitis - viruses distinctive features?
hoarseness in voice
Pharyngitis - Fusobacterium necrophorum prevention?
hygiene
Pharyngitis - S. pyogenes prevention?
hygiene
Pharyngitis - viruses prevention?
hygiene
Pharyngitis - Fusobacterium necrophorum virulence factors?
invasiveness, endotoxin, leukotoxin
Pharyngitis - S. pyogenes distinctive features?
more severe than viral strep
Pharyngitis - Fusobacterium necrophorum Common modes of transmission?
opportunistic
Pharyngitis - S. pyogenes treatment?
penicillin or cephalexin if allergic to penicillin
Pharyngitis - Fusobacterium necrophorum treatment?
penicillin/cefuroxime
Pharyngitis - viruses culture/diagnosis?
rule out S. pyogenes
Acute Otitis Media/Ear infection: Haemophilus influenzae Culture/diagnosis?
same