Chapter 19 Microbiology

pharyngitis

inflammation of pharynx

laryngitis

inflammation of larynx

What diseases/infections are caused by streptococcus pyogenes?

necrotizing fasciitis, strep throat, and complications of strep throat like scarlet fever, glomerulonephritis, and rheumatic fever

What viruses cause the common cold?

rhinovirus, parainfluenza virus, coronavirus, adenovirus, RSV

How is the common cold transmitted?

fomites, respiratory secretions

What are the complications of the common cold?

predisposes individuals to secondary infections

What is the most common and costly respiratory tract infection in children under one?

Respiratory Syncytial virus (RSV)

What are the symptoms of RSV and how is it spread?

causes a viral pneumonia and wheezing; spread on fomites

Are most influenza cases type A or type B?

type A

What are the symptoms of influenza?

cilia are destroyed, fever, fatigue

What are the complications of influenza?

loss of muciliary escalator can cause fluid in lungs, secondary bacterial infections, and death

Otitis media

middle ear infection caused by passage of organisms from pharynx via Eustachian tube to tympanic membrane

Why are children more susceptible to otitis media?

the anatomy of their Eustachian tube is shorter and more horizontal than adults

What are the possible complications of strep throat?

rheumatic fever and glomerulonephritis

What are the symptoms of strep throat? How is treated?

adenoids and lymph nodes swell, sore throat, white, pus-filled lesions, high fever, and no cough or nasal discharge; highly contagious; treated with antibiotics

What is the causative agent of diphtheria?

corynebacterium diphtheria (lysogenic prophage, exotoxin)

What are the symptoms of diptheria?

toxin inhibits protein synthesis causing cell death; pseudomembrane in throat

How is diptheria treated?

antitoxin and antibiotic combo; prevented with DTaP vaccine

What are the complications of diphtheria?

death by suffocation because of blockage by pseudomembrane, myocarditis, polyneuritis, neurological problems including paralysis

What is the causative agent of whooping cough?

Bordetella pertussis (bacteria with endotoxin, exotoxin)

What are the 3 stages of whooping cough?

catarrhal stage, paroxysmal stage, and convalescent stage

Describe the catarrhal stage of whooping cough?

mild, dry persistent cough

Describe the paroxysmal stage of whooping cough

mucus and bacteria in airway immobilize cilia, violent coughing, cyanosis, ropelike mucus, whooping sound as straining to draw air

Describe the convalescent stage of whooping cough

mild coughing

How is whooping cough treated?

antibiotics

What are the complications of whooping cough?

coughing can cause exhaustion, hemorrhage, convulsions, rib fractures, and vomiting

What are the virulence factors of influenza?

hemagglutinins allow the virus to attach and enter host cells; neuraminidase helps the virus get through the thick mucus layer to epithelial cells

Antigenic drift

the gradual accumulation of small genetic mutations in viral surface proteins over time

Antigenic shift

an abrupt, major change in a virus, resulting in new hemagglutinin and/or neuraminidase surface proteins

Mycoplasmas

tiny, slow growing bacteria that lack a cell wall and can not be treated with penicillin

What infections do mycoplasmas cause

walking pneumonia and infections of the lower respiratory tract

What are the symptoms of tuberculosis?

replicates in phagocytes, can live outside the body for a long time and has tubercles with dead necrotic tissue; live in mycobacterium; calcification can be seen on a chest X-ray; disseminates to other organs and bones

How is tuberculosis treated

antibiotics that may be needed for years

What is the causative agent of pneumonia?

streptococcus pneumonia, staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa (can be bacterial, viral, fungal, chemical, or protozoal)

What are the symptoms of pneumonia?

very high fever (over 106 degrees), chest pain, cough, blood or plus in sputum

How is pneumonia treated?

vaccine, antibiotics or antivirals

How is pneumonia transmitted?

carriers and nosocomial

What is another name for strep throat?

bacterial streptococcal pharyngitis

Why is rheumatic fever a common complication of streptococcus pyogenes infections?

heart cell antigens resemble streptococcal antigens, so your immune system attacks and damages the heart and heart valves; can lead to bacterial endocarditis (inflammation of lining and valves of heart)

tubercle

small knobby prominence or excrescence

Mucociliary escalator

a vital innate defense mechanism in the respiratory tract that traps and removes inhaled particles, pathogens, and debris via mucus and cilia