Klebsiella pneumoniae is an opportunistic pathogen frequently involved in severe infections, particularly urinary tract infections, pneumonia, and bacteremia. The international spread of antibiotic resistance in this bacterium is a major public health problem. It is therefore essential to understand the genetic mechanisms involved and to implement appropriate hygiene measures to prevent and stop the transmission of these multi-resistant bacteria in our hospitals. This study made it possible to: highlight the prevalence of multidrug-resistant Klebsiella pneumoniae strains isolated in hospitals in Annaba, Algeria; identify the genetic basis for this resistance; study the possibilities for the transfer of resistance genes; and determine the clonal relationship between these multidrug-resistant strains. This work provides a good foundation on the Klebsiella pneumoniae species and its mechanisms of antibiotic resistance, which will be of interest to microbiologists, infectious disease specialists, and epidemiologists.