Pseudomonas Bacteria and NDM Resistance
Yes, Pseudomonas aeruginosa can produce New Delhi metallo-beta-lactamase (NDM) resistance, though it is not as common as in Enterobacterales. 1, 2
Prevalence and Significance of NDM in Pseudomonas
- NDM-producing Pseudomonas aeruginosa has been detected in clinical isolates, though at lower rates compared to Enterobacterales 1
- Studies from India have reported NDM-1 in 29.23% of carbapenem-resistant P. aeruginosa isolates 2
- NDM-producing P. aeruginosa isolates are typically only susceptible to polymyxin B, making them extremely difficult to treat 1
- The mortality rate for patients with NDM-producing P. aeruginosa infections is high, with most patients succumbing to infection despite treatment 1
Mechanism of NDM Resistance
- NDM is a metallo-β-lactamase (MBL) enzyme that can hydrolyze virtually all β-lactam antibiotics, including carbapenems 3
- NDM genes are typically encoded on plasmids (mobile genetic elements) that can be transmitted between different bacterial species 4
- Currently, 40 NDM variants have been identified in different bacterial strains globally, with NDM-1 being the most common in P. aeruginosa 3, 2
- Unlike in Acinetobacter baumannii where NDM-2 is common, P. aeruginosa predominantly harbors the NDM-1 variant 2
Treatment Options for NDM-Producing Pseudomonas
- For infections caused by metallo-β-lactamase (MBL)-producing bacteria, including NDM-producing P. aeruginosa, ceftazidime/avibactam plus aztreonam should be preferred as first-line therapy 5, 6
- This combination has shown significantly lower 30-day mortality (19.2% vs. 44%) compared to other treatment options 5, 6
- Cefiderocol may also be considered as an alternative option with conditional recommendation (low certainty of evidence) 5
- Novel β-lactam agents such as ceftolozane/tazobactam and ceftazidime/avibactam are currently the first-line options for targeted treatment of difficult-to-treat resistant P. aeruginosa, though their efficacy specifically against NDM-producers may be limited 5
Clinical Implications
- NDM-producing P. aeruginosa isolates are typically only susceptible to polymyxin B and sometimes fosfomycin 7, 1
- Patients with NDM-producing P. aeruginosa infections often have poor outcomes, with high mortality rates 1
- Combination therapy may be considered on a case-by-case basis, especially upon consultation with infectious diseases specialists 5
- Aggressive infection control measures are essential to prevent spread of NDM-producing organisms 8
Diagnostic Considerations
- Molecular methods like PCR are the gold standard for detecting NDM genes in P. aeruginosa 7
- Phenotypic methods such as the Meropenem-EDTA combined disk test have high sensitivity (96.43%) but lower specificity (55.15%) for NDM detection 7
- The modified Hodge test has lower sensitivity (89.29%) and very low specificity (35.15%) for NDM detection 7
NDM-producing P. aeruginosa represents a significant clinical challenge with limited treatment options and high mortality rates. Early detection and appropriate antimicrobial therapy, preferably with ceftazidime/avibactam plus aztreonam or cefiderocol, are crucial for improving patient outcomes.