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