Free images results:
 

Bacteria pictures, stock photos and images

 
1


 
 
1


 
Also, here are some commercial RF-licensed images that match your search criteria:  
Bacteria Stock Photos
Author: Artcp5
Bacteria Stock Photo
Author: Zentilia
Bacteria Royalty Free Stock Photos
Author: Irochka
Bacteria Stock Images
Author: Sage78
Bacteria Royalty Free Stock Photos
Author: Rob3000