Commonest cause of nosocomial infection is
According to the CDC, the most common pathogens that cause nosocomial infections are Staphylococcus aureus, Pseudomonas aeruginosa, and E. coli. Some of the common nosocomial infections are urinary tract infections, respiratory pneumonia, surgical site wound infections, bacteremia, gastrointestinal and skin infections. Ref: Ananthanarayana & panikers 10th edition
Pseudomonas
Staphylococci
Klebsiella
Enterobacteriaceae
miscellaneous