From the Guidelines
Pseudomonas resistance refers to the ability of Pseudomonas aeruginosa bacteria to develop resistance to commonly used antibiotics, making treatment of infections caused by this pathogen challenging.
Definition of Resistance
- Difficult-to-treat resistance (DTR) is defined as non-susceptibility to all first-line, high-efficacy, low-toxicity agents, including ceftazidime, cefepime, piperacillin/tazobactam, aztreonam, imipenem/cilastatin, meropenem, levofloxacin, and ciprofloxacin 1.
- Carbapenem-resistant P. aeruginosa (CRPA) is a specific type of resistance where the bacteria have lost the carbapenem-specific outer membrane porin D (OprD), compromising the effectiveness of carbapenems but not other agents such as piperacillin/tazobactam or ceftazidime 1.
Treatment Options
- Novel β-lactam agents such as ceftolozane/tazobactam and ceftazidime/avibactam are currently the first-line options for targeted treatment of infections caused by Pseudomonas aeruginosa with DTR 1.
- Alternative therapies may include imipenem/cilastatin–relebactam, cefiderocol, and colistin-based therapy 1.
Clinical Considerations
- The choice of therapy should be guided by the susceptibility pattern of the isolate and the severity of the infection 1.
- It is essential to note that the definition of DTR overcomes inconsistencies and limited bedside applicability of the ‘classic’ MDR and extensively drug-resistant (XDR) categories 1.
From the Research
Definition of Pseudomonas Resistance
Pseudomonas resistance refers to the ability of Pseudomonas aeruginosa, a versatile and adaptable bacterial species, to resist the effects of antibiotics [ 2, 3, 4, 5, 6 ]. This resistance can be intrinsic, meaning it is naturally present in the bacteria, or acquired, meaning it is developed over time through gene mutation or acquisition [ 3, 6 ].
Mechanisms of Resistance
The mechanisms of Pseudomonas resistance are complex and multifaceted. They include:
- Unusually restricted outer-membrane permeability [ 3 ]
- Energy-dependent multidrug efflux [ 3 ]
- Chromosomally encoded periplasmic beta-lactamase [ 3 ]
- Gene mutation and acquisition [ 6 ]
- Adaptive resistance under specific situations [ 6 ]
Impact of Resistance
The impact of Pseudomonas resistance is significant, as it can lead to:
- Reduced efficacy of antibiotic treatment [ 2, 4, 5, 6 ]
- Increased morbidity and mortality rates [ 5 ]
- Complicated antibiotic treatment [ 2 ]
- Nosocomial infections, especially in immunodeficient and cystic fibrosis patients [ 6 ]
Emerging Treatments
Emerging treatments for Pseudomonas resistance include: