Staff screening for MRSA: the facts

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When and how should staff be screened for MRSA? And what should you do when they are found to be carrying the infection?

Staff carriage of MRSA

MRSA carriage rates among healthcare workers have generally been reported as low (Nulens et al, 2005; Scarnato et al, 2003). However, in one UK study, 7.7% of GPs were found to have MRSA nasal carriage (Mulqueen et al, 2007). Levels of staff MRSA carriage in published studies are difficult to interpret. This is because staff are exposed to MRSA during the course of their work and may acquire transient carriage of the organisms that is lost when they leave the healthcare environment (Dawson et al, 1997).

Outbreaks of MRSA have frequently been attributed to poor staff hand hygiene (Farrell et al, 1998) or to contaminated equipment (Schultsz et al, 2003; Rampling et al, 2001).

The role of staff in the transmission of MRSA to patients is still considered to be controversial (Simpson et al, 2007). However, a recent extensive review of published studies (Albrich and Harbrath, 2008) has concluded that transmission from staff to patients may be greater than previously thought.

Where staff have persistent carriage of MRSA, their role in transmission to and infection of patients is still questionable. Of 23 healthcare workers who tested positive for MRSA over a two-year period, only one was identified as a source of infection to patients (Lessing et al, 1996).

Where staff are epidemiologically linked to MRSA infections in patients, it is often where they have not responded to a programme of MRSA eradication therapy, where they are increased dispersers of skin scale (Sherertz et al, 2001), or where they have ongoing episodes of infection (Bertin et al, 2006).

In a hospital outbreak of a community-associated MRSA, two healthcare workers who were positive for the outbreak strain had recurrent eye infections or skin abscesses (CDR Weekly, 2006). Evidence that healthcare worker screening and MRSA eradication have been necessary to arrest outbreaks where other infection control interventions have been unsuccessful (Ben-David et al, 2008), supports the current emphasis in the UK guidelines on incremental staff screening.

When and how should staff be screened for MRSA?

Current UK guidance does not support mass staff screening. However, it indicates that, where new cases of MRSA occur among patients on a ward, staff with skin lesions should be referred to an occupational health department for screening and treatment of any dermatological or other long-term condition. In addition, staff screening is indicated where:

Other active control measures (for example, isolation) have not been successful in preventing an outbreak;

Where there are unusual epidemiological issues, for example, a day-case centre where MRSA-positive patients have not overlapped;

Where carriage by staff is suspected, for example, surgical wound infections where the same member of the scrub team has been involved in all cases.

Pre-employment screening is advocated by Albrich and Harbath (2008) but is not included in recommendations for health clearance (Department of Health, 2007a). The procedure for screening is as follows:

• Sites recommended for sampling in staff include the nose, the throat and any areas of abnormal or broken skin (Coia et al, 2006).

• When sampling the nose, throat and skin, swabs can be moistened in sterile 0.9% saline before use, as this aids the transfer of bacteria from the sampling site to the swab (Perry, 2007), increasing the chances of detecting MRSA carriage.

• The request form should state clearly that the specimens are for MRSA screening, to ensure the correct tests are carried out.

• The request form should indicate this is a staff member for confidentiality purposes.

• Screening of the hairline and groin/perineum in staff may be useful in guiding which treatment is used to eradicate MRSA and in determining whether ongoing exclusion from work is required (Coia et al, 2006).

Management of MRSA positive staff

As an MRSA positive status can have ongoing implications for staff and healthcare organisations should have clear plans for management of staff who are found to be positive.

UK guidance on this issue is limited to the principle that only staff with colonised or infected hand lesions should be off work while receiving therapy for MRSA carriage (Coia et al, 2006). Local policies guide post-clearance sampling once the person has been declared free of infection and returned to work. The development of these local policies can lead to inconsistencies in management of staff and discrepancies in restrictions on staff activity and follow up (Hargreaves, 2006).

The RCN (2005) suggests that nurses with persistent MRSA colonisation should be considered to have occupationally acquired the condition and should be treated free of charge. It also recommends that the condition is reported under the Reporting of Injuries Diseases and Dangerous Occurrences Regulations (RIDDOR). In addition, staff should be suspended for medical reasons as opposed to taking sickness absence and should continue to be paid at normal pay levels.

Failure to clear MRSA carriage in staff can have major implications in terms of redeployment if the member of staff works in a high-risk area, for example, as a member of an operating room scrub team or with high-risk patients, for example, those requiring critical care. Before redeployment is considered, extensive efforts to clear carriage should be undertaken. Reports have indicated that extensive cleaning and soft furnishing replacement in the healthcare worker's home (Allen et al, 1997) and screening and treatment of family members (Kniehl et al, 2005) may be necessary to clear ongoing carriage in some healthcare workers.

In the absence of prescriptive guidelines for the process of managing staff who are MRSA positive, adopting the approach for managing staff with hepatitis B (DH, 2007c), could aid in maintaining confidentiality and provide continuity for the affected healthcare worker.

This includes a formal individual risk assessment of the need to exclude the staff member from work and the appointment of a case manager (usually an occupational health physician) to liaise with the affected worker and relevant advisers over treatments and exclusions.

Conclusion

Although staff screening in the UK is not in line with other European countries with low MRSA rates, it is still based on current evidence and level of risk.

Staff screening should follow a strict protocol to ensure only persistent MRSA carriage is detected.

Workers who are found to be positive should be managed equitably and fairly and, with the same level of confidentiality afforded to patients.

This is extracted from a clinical research article, click here for the full paper