Researchers Warn of Dangerous Pseudomonas Bacterium Developing Resistance to Last-Resort Antibiotics

A recent study from Tongji University in China has identified alarming genetic mutations in the bacterium Pseudomonas aeruginosa that grant it resistance to ceftazidime-avibactam, a critical last-line antibiotic used in hospitals. This bacterium is a common cause of hospital-acquired infections, especially in immunocompromised patients, and has increasingly developed defenses against carbapenem antibiotics, making ceftazidime-avibactam a key treatment option. However, the study found enhanced versions of enzymes KPC-71 and KPC-78 that work with existing resistance mechanisms to neutralize this drug, raising urgent concerns about treatment efficacy.

Interestingly, the mutations that confer resistance to this modern antibiotic may also render the bacterium susceptible again to older antibiotics, creating a "swing effect". Researchers caution clinicians that this regained sensitivity could be misleading, as repeated mutations might restore resistance under therapeutic pressure. The specific Pseudomonas strain studied, ST463, is particularly worrisome due to its ability to cause severe infections even before these new mutations emerged.

Pseudomonas aeruginosa is widespread in the environment but becomes highly dangerous when it contaminates medical equipment such as ventilators and catheters in hospitals. While strict hygiene helps reduce infection risks, complete prevention remains challenging. The study underscores the necessity for rigorous monitoring of patients receiving ceftazidime-avibactam to detect emerging resistance promptly and adapt treatments accordingly. The evolving interaction between bacterial mutations and antibiotic therapies continues to pose a significant challenge to medical professionals worldwide.