Transcript Interpreting Microbiology Reports

‫کشت نمونه های مختلف و آنتی بیوگرام‬
Interpreting Microbiology Reports
• The first step in performing cultures is to do a
Gram stain of the collected sample (not for
blood/urine - that is cultured first, then
stained).
• Gram staining results
• few WBCs, no organisms seen.
• many WBCs, many Gram positive cocci in
clusters", or something like that
Interpreting Microbiology Reports
• Step 2: Identification:
• Chemical tests to identify bacteria
• Next the bacteria are cultured and put
through biochemical tests to determine their
identification. This takes a while longer than
the Gram stain
Interpreting Microbiology Reports
• Step 3: Susceptibilities :Finally the bacteria are
tested for their susceptibility to various antibiotics.
• Once this data is known, we can transition from
empiric to definitive therapy if the team has decided
that an infection is indeed present.
• The lab sometimes tests bacteria against many
different antibiotics that we would never actually use
- ignore them.
Urine culture
Urine culture
Different culture methods
Streak culture
Female genital system infections
Vaginal secretion culture
Bacterial vaginosis
Clue cell
Blood culture
Blood culture
Tissue culture
CSF culture
catheter
Susceptibility testing (disk diffusion)
• Muller Hinton agar
• Bacterial inoculums
concentration( %5 Mc
Farland)
• Antibiotic disks
• Pens
• swap
Disk diffusion
Quality control of susceptibility
testing (Kirby-Bauer )
Antibiotic Disk potency (by control organisms)
Mueller –Hinton Agar depth (4 mm)
pH (6.8-7.2)
Instrument failure
Inoculums concentration (0.5 Mac farland)
Temperature (35-37 C)
Moisture
MIC determination
Microdilution
Agar dilution
E test
Gradiant