Microbiological services

1. All renal transplant and dialysis units require ready access to comprehensive microbiology; specific requirements for patient management are discussed in Chapters ….. This chapter deals mainly with aspects of cross-infection in and between patients and staff. It should be noted that results, especially those of tests for blood borne viruses (BBV), will be needed out of hours, and rapidly; this requires collaboration and discussion with local microbiologists.

Blood borne viruses

2. In 1972 the Rosenheim Advisory Group [Department of Health 1972] issued good practice guidelines to prevent the transmission of hepatitis B virus (HBV) in dialysis and transplantation units. New BBV, including particularly hepatitis C and human immunodeficiency virus (HIV) have been identified since then, but separate guidance has not been issued. Further BBV such as hepatitis G [Alter 1996; Masuko et al 1996; Schlaak et al 1996] have been identified; although their carriage rate is greater in patients on dialysis than in the general population, their clinical significance, especially in the long term, remains unclear.

3. Recognised 'universal precautions' against viral transmission, designed both for the protection of the staff and to prevent cross-infection between patients, are an essential discipline in dealing with dialysis patients. All patients with either chronic (CRF) or acute renal failure (ARF) should be managed as if they were chronic virus carriers until they have been fully tested. Regular testing is part of the subsequent management of patients and the running of renal units. Staff training should incorporate and emphasise precautions against BBV. Where available and effective, immunisation should be offered to staff; there is evidence that in the case of HBV this has not been widely practised in the United Kingdom [Jibani et al 1994].

4. In May 1995, the Department of Health asked the Public Health Laboratory Service (PHLS) to prepare advice, in the form of draft guidelines, on the precautions that should be taken in renal units to prevent the transmission of BBV in general. A working party was set up which included representatives of the Royal College of Physicians and the Royal College of Pathologists. Their document was submitted to the Department in late 1996 and is currently under review. When the Department makes its comprehensive report, its recommendations will become the norm.

Recommendation:

The general and universal precautions described in sections 5 - 12 should be observed.

5. Transmission of HBV, HCV and HIV to staff or patients may occur as a result of percutaneous exposure to blood or other body fluids. Virus may also be transmitted directly through droplets or via the hands or forearms of staff to patients direct or to surfaces of equipment. Great care should be exercised treating all patients and all procedures should be reviewed regularly as part of local risk assessment in collaboration with the hospital infection control team.

6. These guidelines should be read in conjunction with all other good practice guidelines which are relevant to maintaining safety in renal units; these include Protection against blood-borne infections in the workplace: HIV and hepatitis: Advisory Committee on Dangerous Pathogens (ACDP), [DH/HSC. 1995] and Guidance for clinical healthcare workers: protection against blood-borne virus infections: the Expert Advisory Group on AIDS, and the Advisory Group on Hepatitis [DOH. 1998]. Guidance for ensuring the safety of transplanted organs is given in Guidance on the microbiological safety of human tissues, organs and cells used in transplantation - Advisory Committee on the Microbiological Safety of Blood and Tissues for Transplantation (MSBT) [DOH 2000]

7. The working environment of a renal unit should be conducive to good clinical practice with adequate lighting and layout including adequate space between patient stations. There should be a plentiful supply of protective clothing including gloves, aprons, visors, and sharps containers. Gloves and aprons should be changed between each patient use. It is recommended that there should be one hand basin for every 3 dialysis stations and one for each isolated or segregated area. Alcoholic hand-wipes are not recommended for routine hand hygiene between patient contact in a Renal Unit.

8. Surfaces of dialysis machines should be washed with soap and water between patient sessions and daily disinfected with chlorine based disinfectant (1,000 ppm chlorine) or some suitable alternative, when stations are used by more than one patient.

9. There must be adequate skin protection for staff working in Renal Units and staff with chronic skin problems should seek occupational health advice regarding their suitability to work in a renal unit. Staff should only eat or drink in designated staff rest areas. Domestic staff should wear aprons and gloves when working in the unit, which should be discarded before leaving the area.

10. The use of multi-use vials should be discouraged. Blood spillages should be dealt with by fully trained staff. Small spillages should be wiped up with a paper towel saturated in a chlorine based disinfectant (10,000 ppm chlorine). Large spillages should either be covered with Dichloroisocyanate granules and left for two minutes before cleaning up with paper towels, or gently flooded with hyperchlorite solution, left for 2 minutes before thoroughly cleaning with water and detergent. Clinical waste should be bagged before taken out of the segregated BBV area (PHLS guidelines to be published). Used haemodialysis and CAPD fluids should be disposed directly to a drain or sluice.

11. Action to be taken in the event of transmission of blood borne viruses is outlined in section11.15. Other measures include stopping elective transfer of patients to other units and notification of any unit of an outbreak of BBV infection if a transfer has taken place in the previous 3 months.

12. Consideration should be given to placing patients infected with BBV on home haemodialysis, CAPD or in a case of HCV considered for a renal transplant.

Recommendation:

		Patients awaiting start of ESRF treatment should be immunised against HBV as soon as possible while their plasma creatinine remains relatively low. (B)
		All long term dialysis patients should be immunised against HBV. Those who develop an adequate antibody response should be given a booster dose of vaccine every 5 years. As there is evidence that non-responders and poor responders derive some benefit from vaccination, they should be given a booster after 1 year and every 5 years thereafter. Non responders should receive a repeat course of vaccine. (B)
		Hepatitis B immunoglobulin and vaccine should be given, if appro-priate, to susceptible patients who have been exposed to the virus. (B)
		Testing should be carried out 3 monthly for HBs Ag, and HCV antibody and annually for HIV antibody. An annual test for HBs Ag is sufficient for patients who have demonstrated immunity. (Good practice)
		The patient's informed consent to testing should be obtained where possible. Those who withhold consent should be managed as though they were BBV infected. However, infected patients should not be denied dialysis. (Good practice)

14. Following a course of immunisation at 0,1, and 6 months, antibody levels should be checked 2 to 4 months after the last dose of vaccine. Patients developing an anti HBs level of 100mlU/ml or more should be given a booster dose at 5 years; poor responders (anti HBs levels of between 10 and 100mlU/ml) should be given a booster dose of 1 and 5 years. Non responders (antibody levels of <10mlU/ml) should receive a repeat course of vaccine.

Footnote: There is continuing debate amongst Virologists about the level of antibody response which protects against infection with hepatitis B. In future a positive antibody level may be all that is required and booster doses become unnecessary. Please consult with local Virological Departments for up-to-date information.

Testing patients for BBV

15. Although the frequency of testing for BBV amongst patients on haemodialysis has varied in Renal Units in the past, it is suggested that regular surveillance is essential to alert Renal Unit staff of any possible outbreaks. HBs Ag, HCV Ab and HIV should be tested before the patient starts or restarts haemodialysis. Immuno-suppressed transplant patients who are HCV, antibody negative and are returning to dialysis should be screened for HCV, RNA before dialysis. HBs Ag and HCV Ab should be tested 3 monthly and HIV annually, and prior to establishment on a renal transplant list. Patients with anti-HBS levels of more than 100mlU/ml need only be tested for HBs Ag annually. More frequent tests will be necessary in certain situations.

i) When a previously unrecognised case of BBV infection occurs, other patients who have shared the same dialysis session should be screened for the virus concerned. If the risk is HBV, patients who have not demonstrated adequate immunity to HBV in the preceeding 12 months (anti HBs <100mlU/ml) should be screened weekly for 3 months, given a booster dose of vaccine and given HB 1G if the anti HBs is <10mlU/ml. The newly infected patient should be dialysed in a separate area using a dedicated machine, if infected with HBV. If a new case of HCV is found, it is suggested that the hepatitis C RNA is obtained among patients who have shared the same dialysis session, and specialist advice requested about the need for further tests.

ii) Any patient who develops abnormal liver function tests should be screened for hepatitis B and C.

iii) Patients who use dialysis facilities outside the UK should be encouraged to be immunised against hepatitis B. On their return they should be tested for HBV and HCV preferably before receiving dialysis in their own Renal Unit and should be treated as potentially infected. A test for HBs Ag should be carried out every 2 weeks for 3 months on patients who have anti HBs levels of <100mlU/ml. A dedicated machine should be used until the risk of HBV infection is discounted. Patients who have dialysed in another British Renal Unit adhering to these standards do not need isolation or use of a dedicated machine providing they have not been accidentally exposed to BBV whilst in the other Unit.

Recommendations:

		Whenever possible, staff should care for only BBV infected or uninfected patients during one shift. If this is not practicable, the more experienced staff should be assigned the task of caring for a mixed group of patients. Designated staff should nurse affected patients when there has been an outbreak of BBV infection in a unit. In the case of hepatitis B, staff who demonstrated immunity should care for the patients whenever possible.
		Carriers of hepatitis B should be dialysed in separate rooms on dedicated machines.
		Carriers of hepatitis C should be dialysed in separate shifts and units should move towards the availability of separate rooms for such patients.
		Dialysis machines used for patients positive for hepatitis C may be used for other patients providing that the dialysis circuit has been adequately decontaminated and the external surface cleaned with some suitable disinfectant between patient use.
		Segregation of HIV infected patients should be considered based on local risk assessment. Their machines should be treated as for patients with Hepatitis C.

Recommended standard

		Staff working in dialysis units in contact with patients, machines or materials used in dialysis should show immunity to HBV. Non, or poor responders should be tested annually for HBs antigen and antibody. Staff who are positive for HBs Ag (e antigen positive or negative) with a viral load of >10 genomes equivalent per ml should not undertake invasive procedures in renal units. (Good practice)
		There is no need to screen for HCV or HIV in staff, but those known to be at risk to acquire infection or known to be infected should be encouraged to seek advice from an Occupational Health Physician. (Good practice)

19. It is now a pre-requisite that all staff working in a Renal Unit should show immunity against HBV, or the offered immunisation before employment. Poor or non-responders to Hepatitis B immunisation should not be debarred from working in a Renal Unit. Although the activities undertaken by staff are not considered exposure prone procedures (as defined by the Department of Health) transmission of BBV from staff to patients cannot be entirely ruled out and staff who are hepatitis B surface antigen positive should not have clinical contact with patients. Non-clinical staff need not be tested for BBV.

21. It is imperative that Renal Units have easy access to Occupational Health Departments and Infectious Disease Control Officers when dealing with outbreaks of BBV and staffing matters relevant to the acquisition of BBV.

22. Patients starting CAPD should be screened for BBV at the start of treatment. They should also be encouraged to be immunised against hepatitis B, as it is likely that patients will need haemodialysis in the short or longer term. There are no recommendations about the periodic testing for BBV, but annual screening or before putting a patient on a transplant list would seem appropriate. Patients on peritoneal dialysis with BBV admitted to hospital do not need isolation, but all body fluids including PD fluid should be handled with care.

23. Universal precautions should be sufficient to avoid cross-infection from and to patients on continuous ambulatory peritoneal dialysis (CAPD) while in hospital (eg, for training or owing to peritonitis); we do not recommend that these patients be isolated in separate rooms.

We would very much like your comments on this document

Please send them to Alison MacLeod, Chairman, Standards & Audit Subcommittee of the Renal Association, at: mmd175@abdn.ac.uk