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- sudden onset of nausea, vomiting, “rice water” diarrhea - 5-10 L H2O loss / day can circulatory collapse - death from dehydration after only 24 hrs w/o Tx pay attention to the types of diarrhea, various bacteria cause (watery, bloody, etc.) Diagnosis Treatment(s) - oral rehydration therapy - tetracycline Prevotella melaninogenicaN = formerlyBacteroides melaninogenicus Lab ID- G- bacilli- grown blackon special agar Metabolism obligate aerobeOther Unique Features Virulence - capsule- collagenase - leukocyte inhibitory factor Transmission constitutes normal flora of oral pharynx, GI & vagina Associated Diseases * Lung infections– necrotizing anaerobic pneumonias from sputum aspiration (drunken or seizure state) * Dental infectionsDiagnosis Treatment(s) * 10-25% are penicillin-resistant
Helicobacter pyloriLab ID- G- slender curved rod- sheathed polar flagella > accounts for characteristic “darting” - oxidase (+)- urease (+)Metabolism - microaerophilic (acidophilic) - fastidious & slow-growing Other Unique Features - highly variable genome= very adaptable - NATURAL TRANSFORMER, change surface Ag →Ab resistance Reside in (±ectopic) gastric mucosa and close to gastric epith cells Virulence - no invasive potential on its own- urease enzyme on surface ammonia > protects against acid > ↑expression at low pH - adhesinsbind epith cells (1) ↑IL-8 ↑TH1 response (2) ↑IL-1 cell act gastric atrophy hypochlorydia, gastric cancer - CagA+path island proteins secrete virulence factors into host, type IV secretion system, loosens TJ’s - Vac+cytotoxin disrupts organelles Most Asian isolates are Cag+Most Cag+are also Vac+Transmission - probably fecal-oralor oral-oral- reservoir = humans (only) - 50% of world population infected > usu. acquired in childhood Associated Diseases * Infection alwaysassoc. w/INFLAMMATION(“gastritis”) - may be aSx * Duodenal ulcer(precursor is Antral gastritis) - preventive for gastric cancer (Note: not true of gastric ulcers) * Gastric ulcer* Gastric cancer (2ndleading worldwide cancer) * MALT lymphoma* chronic/acute antral/corpal gastritis> corpal gastritis can metaplasia * there is a negative assoc. b/w H. pylori infxn & GERD Diagnosis - Endoscopy+ test of antral biopsy for urease activity (CLO test) - common: serology - accurate: stool antigen testing, urea breath test test pts w/ gastric ulcer disease (peptic ulcers or MALT lymphoma) Treatment(s) high variability = high resistance* “cure” w/antacids50% recurrence rate * Antimicrobials eradication - triple combo = omeprazole+ amoxicillin, bismuth, tetracyclines, macrolides, clarithromycin, metronidazol Urea breath test(urea →CO2+ NH4+), inhale tagged C13, C14 Fusobacterium nucleatumNLab IDPale, staining slender G- rodsw/thin pointed endscontrast to F. necrophorum Metabolism obligate anaerobe- butyric acid = principle metabolic end product Other Unique Features - no capsule Virulence - very potentLPS Transmission - constitutes normal flora of mouth, GI & vagina Associated Diseases * Pulmonary Infections* periodontal disease Diagnosis Treatment(s) Metronidazole Gram stain of Fusobacterium nucleatum