Phage Therapy: A Promising Treatment Strategy against Infections Caused by Multidrug-resistant Klebsiella pneumoniae

<i>Klebsiella pneumoniae</i> (KP) is a common and highly pathogenic pathogen, which often causes several serious infections in humans. The rampant and inappropriate use of broad-spectrum antibiotics has fueled a worrisome surge in Multidrug Resistance (MDR) among the strains of <i>K. pneumoniae</i>, which has significantly boosted the risk and complexity of nosocomial infection transmission in clinical settings. Consequently, this situation presents a substantial challenge to the efficacy of anti-infective treatments, making the development of new and innovative therapeutic approaches important. Bacteriophages (phages) are viruses that can infect and kill bacteria. They and their derived products are now being considered as promising alternatives or adjuncts to antimicrobial therapies for treating bacterial infections in humans, which exhibit a remarkable safety profile and precise host specificity. Numerous studies have also unequivocally demonstrated the remarkable potential of phages in effectively combating MDR <i>K. pneumoniae</i> infections both <i>in vitro</i> and <i>in vivo</i>. These studies have explored various approaches to <i>K. pneumoniae</i> phages, such as phage cocktails, phage-derived enzymes, and the synergistic utilization of phages and antibiotics. Therefore, phage therapy is old but not obsolete, particularly in light of the escalating problem of antimicrobial-resistant <i>K. pneumoniae</i> infections. Here, we have presented a comprehensive summary of the current knowledge on phage therapy for <i>K. pneumoniae</i> infections, including phage distribution, <i>in vitro</i> characterization of phages, <i>in vivo</i> investigations, and cases of clinical study. This review highlights the rapid advancements in phage therapy for <i>K. pneumoniae</i>, offering a promising avenue for combating this global public health threat.