STEP 1 Gram Negative Bacteria 1 Flashcards
Colonies grown on MacConkey agar are which color?
Pink
Which bacteria (5) grow on MacConkey’s agar? Which one is weak fermenter? “maConKEE’S agar”
Citrobacter Klebsiella E. coli Enterobacter Serratia (weakly)
How does E. coli ferment lactose?
E. coli produced B-galactosidase which breaks down lactose into galactose and glucose…FUN!!
Which bacteria are resistant to penicillin G? How do we kill these bugs? How are these bugs resistant?
Gram negative bacilli are resistant to PCN G.
Gram negative bacilli MAY be resistant to PCN derivatives such as ampicillin and amoxicillin.
The outer membrane of gram negative bacilli bugs inhibits enter of PCN G and vancomycin
Neisseria comes in two forms Algorithm findings: gram and shape
fermentation
which protease?
N. Gonococci and N. meningococci
Both are GRAM NEGATIVE DIPLOCOCCI
Both ferment GLUCOSE
Both produce IgA protease
How to tell Neisseria species apart?
“MeninGococci ferment Maltose and Glucose” “Gonococci ferments Glucose only”
Gonococci: Capsule Maltose fermentation Vaccine Transmission Causes (5) Prophylaxis (2) Treatment (1 + ?)
NO polysacchardie capsule
NO maltose fermentation
NO vaccine (due to rapid antigenic variation of pilus proteins)
Sexually transmitted
Gonorrhea, septic arthritis, neonatal conjunctivitis, PID, and Fitz-Hugh-Curtis Syndrome
Condoms for sex and erythromycin ointment prevents neonatal transmission
Treatment: CEFTRIAXONE + (azithromycin or doxycycline to cross cover for chlamydia)
Meningococci: Capsule Maltose fermentation Vaccine Transmission Causes (3) Prophylaxis (3) Treatment (2)
Polysaccharide capsule
Maltose and glucose fermentation
Vaccine (none for type B)
Respiratory and oral transmission
Causes meningococcemia, meningitis, and Waterhouse-Friderichsen syndrome
Rifampin, cipro, or ceftriaxone prophylaxis
Treatment: CEFTRIAXONE or PCN G
Lab findings of haemophilus influenzae (size, gram, shape)
Transmission?
Which strain is most invasive?
What do non-invasive strains cause?
Produces which protease?
Small, gram negative rod
Aerosol transmission
HiB
Mucosal infections: otitis media, conjunctivitis, bronchitis
IgA protease (invades mucosal surfaces)
H. influenza grows on which agar? What requirements (2)
Chocolate agar Factor V (NAD+) and X (hematin)
H. influenza causes which disease states? “haEMOPhilus”
Epiglottitis (children) Meningitis Otitis media Pneumonia
How to treat H. influenza mucosal infections
Amoxicillin (+/- clavulanatic acid)
How to treat H. influenza meningitis? Prophylaxis?
Ceftriaxone for treatment
Rifampin for prophylaxis
Describe the HiB vaccine. When to give the HiB vaccine?
Type B capsular polysaccharide conjugated to diphtheria toxoid. Given between 2-18 months
Legionella staining and shape
Gram NEGATIVE ROD….doesn’t stain well Use SILVER STAIN
How is legionella cultured?
Grown on CHARCOAL yeast extract culture with IRON and CYSTEINE
How is legionella detected clinically?
Antigen in urine
Legionella transmission
Aerosol transmission from environmental water source: air conditioning, hot water tanks, hot tubs NOT FROM PERSON TO PERSON
Legionella treatment:
macrolide or quinolone
Legionnaires’ disease symptoms:
Severe pneumonia
Fever
GI
CNS disturbances