Micro Gram - Flashcards
Gram - diplococci, ferment maltose and glucose, polysaccharide capsule
Neisseria meningitidis
Gram - diplococci, ferments glucose but not maltose, no polysaccharide capsule
Neisseria gonorrhoeae
What can neisseria gonorrhoeae cause?
Gonorrhea, septic arthritis, neonatal conjunctivitis (2-4 days after birth), PID, and Fitz-Hugh-Curtis syndrome
Treatment for neisseria gonorrhoeae
Ceftriaxone (+ azithromycin or doxycycline, for possible chlamydia coinfection)
What can neisseria meningitidis cause?
Meningococcemia with petechial hemorrhages and gangrene of toes, meningitis, Waterhouse-Friderichsen syndrome
How is neisseria meningitidis treated?
Ceftriaxone or penicillin G
How are close contacts to neisseria meningitis patient treated?
Rifampin, ciprofloxacin, or ceftriaxone
Small gram - coccobacillary rod. Aerosol transmission
Haemophilus influenza
What can H influenzae cause?
Epiglottitis, meningitis, otitis media, pneumonia
What kind of media is needed to grow H influenzae?
Chocolate agar - contains factors V (NAD+) and X (hematin) for growth. Can also be cultured with S aureus
How is H influenzae treated?
Amoxicillin +/- clavulonate for mucosal infections, ceftriaxone for meningitis, rifampin prophylaxis for close contacts
Gram - aerobic coccobacillus
Bordetella pertussis
What are the virulence factors for bordetella pertussis?
Pertussis toxin (disables Gi), adenylate cyclase toxin (increases cAMP), and tracheal cytotoxin
What are the 3 clinical stages of pertussis?
Catarrhal - low grade fevers, coryza
Paroxysmal - paroxysms of intense coughing followed by inspiratory whoop, posttussive vomiting
Convalescent - gradual recovery of chronic cough
Gram - rod, grams stain poorly so silver stain is used. Grows on charcoal yeast extract medium with iron and cysteine
Legionella
How is legionella pneumophila transmitted?
Aerosol transmission from environmental water source habitat. No person-person transmission
How is legionella pneumophila treated?
Macrolide or quinolone
Legionnaire’s Disease
Severe pneumonia (often unilateral and lobar), fever, GI and CNS symptoms. Common in smokers and in chronic lung disease
Aerobic, motile, gram - rod. Non-lactose fermenting. Oxidase +. Mucoid polysaccharide capsule
Pseudomonas aeruginosa
What infections/disease is pseudomonas associated with?
Pneumonia, sepsis, ecthyma gangrenosum, UTIs, diabetes, osteomyelitis, otitis externa, nosocomial infections, addicts, skin infections
What do pseudomonas produce?
Phospholipase C (degrades cell membranes)
Endotoxin (fever, shock)
Exotoxin A (inactivates EF-2)
Pigments: pyoverdine and pyocyanin (blue green)
Reactive oxygen species
What drugs are used to treat pseudomonas?
Carbapenems, aminoglycosides, monobactams, polymyxins, fluoroquinolones (ciprofloxacin, levofloxacin), third and fourth generation cephalosporins (ceftazidime, cefepime), extended spectrum penicillins (piperacillin, ticarcillin)
Gram - rods, non-lactose fermenters, oxidase -, can invade the GI tract via M cells of Peyer patches
Salmonella and Shigella
What do antibiotics do against Salmonella infection?
Prolong duration
Which bacteria ferment lactose?
Pink colonies on MacConkey agar
Citrobacter, Klebsiella, E. coli, Enterobacter
E. coli virulence factors
Fimbriae, K capsule, LPS endotoxin
What can the shiga like toxin in O157:H7 E. coli cause?
Hemolytic uremic syndrome - anemia, thrombocytopenia, and acute renal failure due to microthrombi forming on damaged endothelium leading to mechanical hemolysis (schistocytes), platelet consumption, and decreased renal blood flow
Currant jelly sputum
Klebsiella
Intestinal flora that causes lobar pneumonia in alcoholics and diabetics when aspirated
Klebsiella
Gram -, comma or S shaped, oxidase +, grows at 42 degrees C
Campylobacter jejuni
What part of the stomach does H pylori colonize?
Antrum
How is H pylori treated?
Amoxicillin, clarithromycin, proton pump inhibitor
