Common sites of clinical isolation: blood cultures from patients who have neutropenia with oral ulcers (source of the Capnocytophaga), soft tissue infections, peritonitis, and endocarditis
Legionnaire's disease first recognized during an epidemic of pneumonia that occurred among members of the Pennsylvania American Legion who had gathered in Philadelphia to celebrate the bicentennial
Caused by inhalation of bacterial toxins or an acuteallergicreaction to the bacteria
Affects previously healthy individuals who complain of flulike symptoms of fever, headache, and myalgia that last 2 to 5 days and then subside without medical intervention
1. Catarrhalstage: symptoms are the same as for a mild cold with a runny nose and mild cough, lasts several weeks
2. Paroxysmalstage: severe and violent coughing, 15 to 25 paroxysmal coughing episodes can occur in 24 hours, vomiting and "whooping" (the result of air rapidly inspired into the lungs past the swollen glottis), lasts 1-4weeks
3. Convalescentphase: begins within 4weeks of onset with a decrease in frequency and severity of the coughing spells
Major virulence determinants of Bordetella pertussis
Fimbriaetypes2and3: serotype-specific agglutinins for colonization of respiratory mucosa
Filamentous hemagglutinin (FHA): mediates adhesion to the ciliated upper respiratory tract
Pertactin (PRN): mediates Eukaryotic cell binding and is highly immunogenic
TrachealcolonizationfactorBrkA
Pertussis toxin: encoded by ptx gene which is an A/B toxin related to choleratoxin, induces lymphocytosis and suppresses chemotaxis and oxidative responses in neutrophils and macrophages
Adenylatecyclasetoxin: hemolyzes red cells and activates cAMP, thereby inactivating several types of host immune cells
Dermonecrotictoxin: exact role unknown
Trachealcytotoxin: ciliary dysfunction and damage
Endotoxin: lipopolysaccharide
TypeIIIsecretion: to transport proteins directly to host cells
Outer membrane: inhibits host lysozyme
Siderophoreproduction: prevents host lactoferrin and transferrin from limiting iron