Background: Acinetobacter baumannii is an opportunistic pathogen, related with nosocomial infections such as bacteremia, urinary tract infections, and ventilator-associated pneumonia. Multidrug resistant (MDR) A. baumannii strains are first line causes of infection, especially in patients hospitalized at intensive care units (ICUs). Infection with MDR A. baumannii strains has a longer duration at ICUs and hospitals. There are studies using molecular methods which can differentiate MDR A. baumannii strains at the clonal level. This helps controlling these resistant strains and prevents their epidemy.