Bacteria under Microscope

Vancomycin intermediate resistant
Staphylococcus aureus(VISA)
staph aureus vancomycin intermediate resistant
Under a high magnification of 10,000x, this scanning electron micrograph (SEM) shows a strain of Staphylococcus aureus bacteria taken from a vancomycin intermediate resistant culture (VISA, Vancomycin Intermediate resistant Staphylococcus aureus).

Under SEM, one can not tell the difference between bacteria that are susceptible, or multidrug resistant, but with transmission electron microscopy (TEM), at least with VISA isolates one can see a thickening in the cell wall that may attribute to their reduced susceptibility to vancomycin .
Text&Photo CDC, Public Health Image Library (PHIL)
This image is in the public domain and thus free of any copyright restrictions.
Public Health Image Library (PHIL)
Bacteria under Microscope
 

Gram-stain:

Gram-positive cocci
 

Microscopic appearance:

Cocci in clusters
 

Clinical significance:
  • VISA and VRSA are specific types of antimicrobial-resistant staph bacteria. While most staph bacteria are susceptible to the antimicrobial agent vancomycin some have developed resistance. VISA and VRSA cannot be successfully treated with vancomycin because these organisms are no longer susceptibile to vancomycin.
    Text: PHIL
 

Colony morphology:

  
See Staphylococcus aureus identification
 
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