<prompt> Most of the pseudomonas infection is based on oppounism. The exception is:GlandersPneumoniaOtitis mediaSkin infection  <response>: The pseudomonas: They are heterogeneous group of gram-negative bacteria Common feature among them is the inability to ferment lactose. There are three medically impoant genera--Pseudomonas, Burkholderia, and Stenotrophomonas The pathogenicity of most is based on oppounism; the exceptions are the organisms that cause melioidosis B. pseudomallei and glanders B. mallei P. putida, P. fluorescens, and P. stutzeri infect humans rarely Ref: Harrison, E-18, P-1266. 