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Micro 8 Haemophilus, Bordetella, Chlamydia (gram -)

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cipoxixo's version from 2017-01-21 14:50

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Question Answer
Haemophilusgram (-) Haemophilus "blood loving" requires factor X (hematin) and factor V (NAD) grow on chocolate agar lysed RBC in CO2 rich environments(NOT blood agar)
H Influenza Bacteriologysmall gram (-); coccus and bacillus forms; facultative anaerobes, grows RAPIDLY, but nutritoinal fastidious; does not grow on blood agar (does on chocolate)
H. Influenza Disesetype B capsule (HiB)**, causes meningitis in children 6month --> 3 yrs; Runny nose, fever, headache --> meningitis; KNOW TYPE B is bacterial meningitis in children**
H Influenza VirulenceCAPSULE** is major virulence factor, Polyribosyl ribitol phosphate (PRP); PRP capsule associated with Type B --> antiphagocytic and induces compliment activation pathway --> allows invasion in to CSF
H. Influenza Transmissionsecretions and aerosol; 6-11 month peak incidence if unvaccinated
H. Influenza Diagnosispositive culture, HiB, gram (-) culture in CSF, blood culture, PRP detection in CSF --> MUST REPORT "when you get the flu, mom goes to five (V) and dime (X) to get chocolate (agar)
Tx of H. Influenzatreat based on presumptive diagnosis! dont wait for labs; use corticosteroids to reduce brain inflammation and residual neurological effects
H. influenza Vaccineanticapsular antibodis are main defense; protein conjugated PRP vaccine (component of type B capsule --> effective in children less than 18 month and confers T cell dependent properties (PRP vaccine alone do NOT); start at 2mo (2-3 doses); 15-59 mo (give 1 dose) after 60 months (do not need it)
H. Influenza Epidemiologynon-encapsulated strains part of normal flora in URT; 3-7 of healthy individuals carry Hib strain
Acute Epiglottitis***swollen cherry-red epiglottis results in obstruction of upper airway and suffocation; almost 100% fatal without prompt treatment!; "haEMOPhilus --> Epiglottitits, Meningitis, Otitis media, Pneumonia
Nontypeable H. Influenzaunencapsulated; in COPD patients, otitis media, meningitis in adults, chronic sinusitis
H. ducreyiChancroid**, sexually transmitted; requires only Factor X (hematin)
H. aegypticusconjuctivitis (pink-eye)
H. parainfluenzaonly requires factor V;
Bordetella Pertussissmall gram (-) strict aerobe, SLOW growing (unlike h.flu), nutritionally fastidious; WHOOPING COUGH; highly contagious (droplets), Stage 1 (cararrhal) mimic URI; Stage 2: Severe cough with inspiratory wheeze (whoop) Stage 3: Regeneration of ciliated epithelium, cough subsides; Complication of bronchopneumonia and neurological damage form cough
Pertussis Pathogenisiscolonizes and destroys ciliated epithelium; non-invasive --> complex toxigenic disease with peripheral lymphocytosis
Stage 1**Adherence; Filamentous hemagglutin (FHA) (major adhesin)*** Antibody to FHA is protective; Treat with antibiotics to reduce symptoms
Stage 2**Toxigenic; Pertussis toxin***--> uncouples Gi protein from receptors (turns off switch off); tracheal cytotoxin induces IL-1 --> NO synthesis --> ciliated epithelial death --> cough, Adenylate Cyclase Toxin; Antibiotics will NOT change course --> SUPPORTIVE care
Stage 3Recovery
Pertussis toxin (TEST)***ADP-ribosylates Gi,o,t and uncouples receptor (turns off switch off) --> increased cAMP, insulin production, lymphocytosis; EXAM: Targets trimeric G protein to stop it from activating to G-protein(alpha) which is active
Pertussis Diagnosiscough > 2 weeks /lymphocytosis, fragile organism that requires special culture Bortdet-Gengou agar; toxin mediated disease
DTaP Vaccine5 doses; 2,4,6,12-15 mo, 4-6 yrs
H. Influenza v. PertussisH.Flu --> invasive organsism that causes meningitis/otitis media in children and pneumonia in adults; Pertusis: toxigenic / non-invasive disease that causes whooping cough by increasing cAMP by uncoupling Gi,o
Chlamydia psittaciintracellular bacteria, slow growing; gram (-); Two forms: 1.) Elementary body - inactive infectous stage "Elementary body in Enfectious and Enters cell" 2.) Reticulate body- "Replicates in cell"; animal to human transmission "PARROTS" --> Tx: tetracyclines
Summary:
H. InfluenzaFastidious, gram (-), RAPID growing; Hib causes bacterial meningitis in children; effective PRP capsule vaccine; Unencapsulated opportunistic pathogen --> inflammation
Bordetella PertussisFastidious, gram (-), SLOW growing; toxin causes whooping cough; effective aP vaccine (formalin treated PT (toxoid)
Chlamydia psittaciIntracelular, slow growing "Chyamys = cloak", causative agent of parrot fever
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