1/26/2016 Microbial Diseases of the Upper Bacterial Diseases of the Upper Respiratory System Respiratory System ·Pharyngitis -Sore throat,inflammation of mucus membranes in the throat Learning Objective ·Laryngitis -Larynx is the site of infection ·Tonsillitis List the causative agent,symptoms, -Inflamed torsils prevention,preferred treatment,and ·Sinusitis laboratory identification tests for streptococcal pharyngitis,scarlet fever -Usually self-limiting diphtheria,cutaneous diphtheria,and otitis media. Bacterial Diseases of the Upper Respiratory System Diphtheria Streptococcal pharyngitis(strep throat) Caused by Corynebacterium diphtheriae -Caused by group A streptococci(GAS) -Gram-positive rod:pleomorphic .Streptococcus pyogenes Forms a tough grayish membrane in the throat -Resistant to phagocytosis -Streptokinases-lyse clots -Fibrin and dead tissue -Streptolysins-cytotoxic to cells -Blocks passage of air to the lungs -Local inflammation,fever,tonsillitis Exotoxin produced by lysogenized bacteri enlarged lymph nodes -Diagnosis-enzyme immunoassay tests ci5botdonogeshe Scarlet fever Cutaneous diphtheria-forms skin ulcer -Erythrogenic toxin produced by Prevented by DTaP vaccine lysogenized5.pyogenes -Diphtheria toxoid1/26/2016 3 Microbial Diseases of the Upper Respiratory System • Pharyngitis – Sore throat, inflammation of mucus membranes in the throat • Laryngitis – Larynx is the site of infection • Tonsillitis – Inflamed tonsils • Sinusitis – Heavy mucus discharge from the sinuses – If opening is blocked, then pressure and pain occur – U ll lf Usually self-li iti m ng • Epiglottitis – A flap-like structure that prevents ingested material from entering the larynx – Most life-threatening disease of the upper respiratory system; develops rapidly with death in a few hours – Haemophilus influenzae type B Bacterial Diseases of the Upper Respiratory System Learning Objective List the causative agent, symptoms, prevention, preferred treatment, and laboratory identification tests for streptococcal pharyngitis, scarlet fever, di hth i t s di hth i d di phtheria, cu taneous di phtheria, and otitis media. Bacterial Diseases of the Upper Respiratory System • Streptococcal pharyngitis (strep throat) – Caused by group A streptococci (GAS) • St t rep ococcus pyogenes – Resistant to phagocytosis – Streptokinases - lyse clots – Streptolysins - cytotoxic to cells – Local inflammation, fever, tonsillitis, enlarged lymph nodes – Diagnosis - enzyme immunoassay tests • Scarlet fever – Erythrogenic toxin produced by lysogenizedS. pyogenes Diphtheria • Caused by Corynebacterium diphtheriae – Gram-positive rod; pleomorphic • F m g g y mm or ms a tou gh gra yish m e mbrane in the throat – Fibrin and dead tissue – Blocks passage of air to the lungs • Exotoxin produced by lysogenized bacteria – Circulates in the blood; damages the heart and kidneys • Cutaneous diphtheria – forms skin ulcer • Prevented by DTaP vaccine – Diphtheria toxoid