How to manage increasing NDM (New Delhi metallo-beta-lactamase) prevalence in a healthcare setting?

Managing Increasing NDM Prevalence in Healthcare Settings

Implement aggressive infection control bundles combining contact precautions, patient isolation, active surveillance screening, enhanced environmental cleaning, and antimicrobial stewardship programs to contain NDM-producing carbapenem-resistant Enterobacteriaceae (CRE) transmission. 1, 2, 3

Immediate Infection Control Measures

Hand Hygiene and Contact Precautions

• Reinforce strict hand hygiene protocols with alcohol-based hand rubs before and after all patient contacts, with mandatory monitoring and feedback to healthcare workers to achieve compliance. 1, 2
• Implement contact precautions requiring gloves and gowns for all encounters with colonized or infected patients, with audit of adherence to ensure correct performance. 1, 2
• Prohibit artificial nails among healthcare workers as they harbor resistant organisms. 1, 2

Patient Isolation and Cohorting

• Isolate all NDM-positive patients in single rooms immediately upon identification to reduce acquisition risk. 1, 2
• When single rooms are unavailable, cohort patients with the same NDM-producing organism in designated areas with dedicated staff. 1, 2
• Do NOT discontinue isolation or contact precautions during hospitalization, as colonization persists for months. 1
• Use alert codes to flag previously positive patients at readmission or transfer to other units. 1, 2

Active Surveillance and Screening

Screening Protocols

• Perform active screening cultures at hospital admission for high-risk patients, including those with prior ICU stays, prolonged antibiotic therapy (especially carbapenems), central venous catheters, mechanical ventilation, or recent hospitalization abroad (particularly India, Pakistan, Southeast Asia). 1, 2, 3, 4
• Screen using rectal or perirectal swabs, inguinal area swabs, and samples from manipulated sites (catheters, wounds). 1
• Implement pre-emptive contact precautions for patients transferred from ICUs or wards with known NDM cases while awaiting screening results. 1, 2

Communication Systems

• Ensure communication of NDM status before transferring patients to other healthcare facilities (acute and non-acute care). 1
• Maintain surveillance systems to track transmission patterns, as NDM genes spread through both clonal bacterial transmission and horizontal plasmid transfer between different bacterial species. 5, 6

Environmental Cleaning and Disinfection

Monitor cleaning performance with audit and feedback to ensure consistent environmental cleaning. 1, 2

Specific Cleaning Protocols

• Review and specify which items require disinfection, which disinfectant agents to use (avoiding benzalkonium chloride which allows mycobacterial growth), proper dilutions, and contact times. 1, 2
• Dedicate non-critical patient-care equipment to single patients or cohorts of NDM-positive patients. 1, 2
• Implement specific protocols for disinfection of endoscopes and respiratory equipment, avoiding tap water for terminal rinses. 1
• Consider unit closure for intensive cleaning if transmission continues despite basic measures. 1

Antimicrobial Stewardship

Carbapenem Restriction

• Implement aggressive antimicrobial stewardship programs to restrict carbapenem use, as prior carbapenem exposure is the strongest predictor for NDM acquisition (OR 8.4). 3, 4
• Plan interventions to restrict broad-spectrum antibiotic usage including fluoroquinolones and third-generation cephalosporins. 2, 3
• Use procalcitonin-guided therapy to reduce unnecessary antibiotic exposure in respiratory infections and sepsis. 3

Treatment Considerations

• For confirmed NDM infections, ceftazidime-avibactam plus aztreonam is first-line therapy (30-day mortality 19.2% vs 44% with other options). 7
• Tigecycline shows highest susceptibility rates (86.5%) among available agents for NDM-producing Enterobacterales, followed by eravacycline (66.2%). 8
• Recognize that 75.3% of NDM isolates display difficult-to-treat resistance and 42.2% are extensively drug-resistant. 8

Education and Administrative Support

Staff Education

• Conduct regular educational programs ensuring healthcare workers understand why NDM organisms are epidemiologically critical, why prevention is essential, and which control measures are effective. 1, 2
• Hold multidisciplinary meetings every 2-4 weeks with physicians, nurses, respiratory technicians, pharmacists, and environmental service personnel to review adherence audits and provide feedback. 1, 2

Administrative Infrastructure

• Establish administrative support including economic and human resources dedicated to NDM containment. 2
• Include environmental personnel (estates, domestic, janitorial staff) in infection prevention infrastructure. 2

Critical Pitfalls to Avoid

• Do not allow patients to walk in hallways if incontinent, as environmental contamination occurred in documented outbreaks. 1
• Avoid tap water contact with central venous catheters, surgical wounds, or for rinsing medical equipment, as water systems harbor NDM organisms. 1
• Do not rely on single interventions; bundled approaches are necessary as NDM spreads through multiple mechanisms including clonal transmission and plasmid-mediated horizontal gene transfer. 5, 6
• Recognize that standard disinfectants (organomercurials, chlorine, 2% formaldehyde) are ineffective against these organisms. 1

Monitoring Outcomes

Track transmission patterns through molecular epidemiology, as identical plasmids (particularly IncX3 and IncC types) can transfer between different bacterial species in the same patient and between patients. 5, 6 The increasing prevalence of blaNDM-5 over blaNDM-1 suggests ongoing evolution requiring continuous surveillance. 6