The therapeutic potential of phage pT2784 against ST40-KL47 type <i>Acinetobacter baumannii</i> and bacterial fitness trade-offs

The rise of antibiotic-resistant <i>Acinetobacter baumannii</i> is a critical global health threat, urgently demanding new treatments. This study introduced a newly discovered phage, pT2784, which exhibited potent and specific lytic activity against <i>Acinetobacter baumannii</i> ST40-KL47. Crucially, we demonstrated that upon the emergence of phage resistance, the bacteria concurrently underwent a significant attenuation of their pathogenic potential. This work not only provided a promising new candidate for phage therapy but also revealed a fundamental trade-off where the path to phage resistance leads to attenuated bacterial virulence, offering a strategic advantage for managing challenging <i>Acinetobacter baumannii</i> infections.