<prompt> In a patient of nephritic syndrome with spontaneous bacterial peritonitis, which one of the following micro-organisms is most commonly involved?ProteusEscherichiaPneumococcusStaphylococcus  <response>: Spontaneous bacterial peritonitismeans peritonitis without any apparent source of contamination.Enteric gram-negative organismE. coli most commonly encountered but sometime gram-positive organism such as streptococci and enterococci also responsible. 