Effectiveness of polyhexanide, chlorhexidine with neomycin and mupirocin for nasal methicillin-resistant...

The bacterium Staphylococcus aureus is a leading cause of hospital-acquired infections. These infections are difficult to treat when there is increasing resistance to penicillin, known as methicillin-resistant Staphylococcus aureus. Patients who carry Staphylococcus aureus in the nose and skin are prone to developing infections and many patients admitted to hospital are routinely 'decolonised' to reduce this risk. The current standard treatment for nasal decolonisation is the antibiotic nasal mupirocin. There are concerns about over-reliance on a single treatment and the risk of mupirocin-resistant methicillin-resistant Staphylococcus aureus. Robust evidence for alternatives to mupirocin is required.

To investigate whether there are clinically and cost-effective alternatives to mupirocin for early nasal decolonisation of methicillin-resistant Staphylococcus aureus among adult hospital inpatients.

We designed a multicentre, three-arm parallel-group, non-inferiority, randomised controlled trial with economic and qualitative evaluations, to recruit 3000 participants.

Adult hospital inpatients identified as being colonised with methicillin-resistant Staphylococcus aureus on routine hospital admission screening were eligible for inclusion.

Participants were randomised (ratio 1 : 1 : 1) to receive one of the following decolonisation treatments: mupirocin (2%) nasal ointment (3 g), polyhexanide (0.1%) nasal gel (30 ml) or chlorhexidine (0.1%) with neomycin (0.5%) nasal cream (15 g). Neither participants nor the investigators were blind to treatment allocation.

The primary outcome was successful early nasal decolonisation, defined as a negative trial specific nasal methicillin-resistant Staphylococcus aureus swab taken 48 hours following treatment completion. Secondary outcomes included successful early nasal decolonisation of methicillin-resistant Staphylococcus aureus not fully susceptible to mupirocin, successful late nasal decolonisation, acceptability of treatment to patients, methicillin-resistant Staphylococcus aureus infections, length of hospital inpatient stays and re-admissions, adverse events and mortality. Outcomes were collected up to 4 weeks following treatment completion.

Recruitment and retention of participants were much lower than expected. In total, 297 patients were assessed for eligibility and 32 patients randomised. All participants received treatment as allocated. Seven participants withdrew from the study. The mean age was 73.8 years (standard deviation 16.6 years), with 62.5% (n = 20) of participants being male. Semistructured interviews were undertaken with patients (N = 5), clinical teams (N = 19) and clinical trials unit staff (N = 5) to explore barriers and facilitators to recruitment and consent processes. Data from the qualitative evaluation contributed to progress discussions at trial management meetings and resulting remedial activities undertaken.

The trial closed early after reaching < 2% of the recruitment target. The planned statistical and health economic analyses could not be conducted due to the limited data. The study objectives were not addressed due to poor recruitment.

It was not feasible to recruit to this trial in the current context, due to a reduced level of methicillin-resistant Staphylococcus aureus testing being undertaken in hospitals within the National Health Service.

To facilitate future research, further understanding of the routine decolonisation pathways in line with the revision to national guidance issued in 2021 is required. Validation of methicillin-resistant Staphylococcus aureus viability to increase processing time for nasal swabs could be undertaken and further exploration of the use of self-swabbing at home.

This synopsis presents independent research funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme as award number NIHR132718.