Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a global problem in infection control. For many years it has been a major cause for nosocomial infections in many countries 12. The proportion of methicillin resistance among clinical isolates of S. aureus is still increasing. In southern European countries, the proportion may be as high as 55% 34. MRSA now even becomes an increasing problem in the community 56. Transmission of MRSA in community has been shown to be as high as 60% 7. Family members who are living with MRSA carriers are in danger of MRSA transmission 7. Dermal colonization with MRSA may be persistent, especially in the groin 8. That is why attempts are often undertaken to treat colonized MRSA patients 9. Antibiotics were shown to be effective in uncontrolled and controlled trials with eradication rates between 53% and 85% 101112. But antibiotics are considered to be inappropriate for patients who are only colonized and not infected with MRSA 13. One reason is their potential to cause adverse effects, especially allergy, which can not be justified for patients who do not have an infection. More important is the risk of emergence of vancomycin-resistance in S. aureus 14. Topical antiseptic measures, however, are normally employed 15. The nasal cavity is usually treated with mupirocin or with tolerable antiseptics 16. Dermal colonization is eradicated with antiseptic liquid soaps 13 Only few studies have addressed the question of MRSA eradication among colonized patients with liquid soaps in combination with nasal treatment. All of them are uncontrolled trials and most of them have different types of biases.

Aim of our study was to determine the efficacy of the antiseptic soap Stellisept scrub in combination with mupirocin for eradication of MRSA among colonized patients with evidence of dermal colonization (no selection bias), without concomitant antibiotic therapy (no treatment bias) and with regular screening investigations (no outcome bias).

Fifty patients were treated between 2001 and 2002 in the 6 hospitals, mainly in surgery, internal medicine, intensive care or other departments such as gynecology (n = 2), neurology (n = 2), urology (n = 1) or dermatology (n = 1; Table 1). Four of the 50 patients were discharged early resulting in a lack of information on the outcome (colonization with MRSA after antiseptic treatment). Eight patients received concomitant systemic antibiotic therapy initiated after inclusion in the study. Three patients had a colonized or infected wound which was treated during the study. All of them were excluded resulting in a total of 35 cases with proven dermal MRSA colonization and without concomitant systemic antibiotic therapy.

21 of the 35 patients were male (60%), the mean age was 69.1 years (minimum 27 years, maximum 91 years). Nasal colonization was found in 21 of 28 patients (75%), 7 patients were without nasal screening prior to the antiseptic treatment. Dermal colonization was documented mainly in the groin (80%), followed by axilla (25.7%), perineum (20%), forehead (5.7%), umbilicus (5.7%) and upper leg (2.9%; Table 2). Multiple colonization of the skin was found in 34.3% of the patients.

After one cycle of antiseptic body wash and concomitant nasal antisepsis with mupirocin, 25 of the 35 patients were found to be MRSA free (71.4%; Table 2). The mean duration of treatment was 6.7 ± 2.5 days. Successful eradication of MRSA was confirmed with three negative consecutive series of swabs in 16 patients (64%). Two consecutive series of swabs were negative in five patients (20%) and one series of swabs was negative in four patients (16%) which was explained by early discharge of the patient. Treatment failures after the first cycle were due to persistent colonization of the same skin area (5 of 10), colonization of another skin area (4 of 10) and persistent colonization of the nasopharynx (1 of 10). Of the remaining 10 patients, two were not treated any further due to discharge and 8 underwent a second treatment cycle with seven of them being MRSA negative afterwards (total of 91.4% being MRSA negative). The mean duration of treatment in the second cycle was 6.4 ± 2.1 days. In order to confirm successful eradication of MRSA after the second cycle, three consecutive series of swabs were negative in six patients (85.7%) and two consecutive series of swabs were negative in one patient (14.3%). The one patient remained colonized on the same skin area without nasal carriage and underwent a third treatment cycle resulting in dermal MRSA eradication (total of 94.2% being MRSA negative; Table 2). Three series of consecutive swabs were negative to confirm successful eradication of MRSA.

No patient had to discontinue the antiseptic body wash due to dermal intolerance or uncomfortable perception of the product.

Although eradication of MRSA from colonized patients is regarded as a key element in prevention of transmission in a hospital, so far only few studies have addressed the clinical efficacy of antiseptic soaps in combination with a nasal antiseptic for that purpose. No study was found with a positive or negative control for the antiseptic skin treatment, only one study was found with a negative control for nasal mupirocin (Table 3). In addition, most of the uncontrolled trials contain substantial biases which limit or even diminish the value of them.

In our study, we found an eradication rate after one treatment cycle of 71.4% which is comparable to antibiotic treatment 1018. After two treatment cycles, the rate was 91.4% and came up to 94.2% after a third treatment cycle. With no other antiseptic soap we were able to find comparable data which are not confounded by a lack of evidence for initial MRSA colonization, concomitant antibiotic therapy or screening cultures during antiseptic treatment.

One limitation of our study is the lack of a control. We can not exclude that washing with plain soap and water or doing nothing would not have had a similar effect regarding the eradication of MRSA, although it is very unlikely based the persistence of MRSA colonization in the groin 8. It would have been much more interesting to compare Stellisept scrub with either a non-medicated soap (negative control) or another antiseptic soap (e.g. based on chlorhexidine). But the use of non-medicated liquid soap would have been acting against the German recommendation for MRSA patients (antiseptic soaps or liquid preparations should be used for treatment of the skin) 13. The use of medicated soap, however, would have been an interesting option, ideally in a double-blind randomized design. But chlorhexidine as the most common active agent for this type of treatment has been described in recent studies with artificial contamination of fingers with MRSA to have no advantage compared with non-medicated liquid soap 1920. It was therefore not considered to be suitable as a positive control 21. That is why an open uncontrolled design was chosen.

Another limitation is the rather short follow-up of 5 days after termination of the treatment (2 days wash-out and 3 days screening cultures). Most patients stayed as long in their hospital as it was necessary to complete the screening cultures. The main reason for even shorter follow-up is discharge of the patient from a hospital. Continuation of hospital stay with the only aim to complete screening cultures was not possible in our study. Follow-up was unknown in some studies 2223, shorter in others 24 or longer 1018, but in some studies not for all patients 825.

Treatment failures after the first cycle were mainly observed at the same or another skin site. The surrounding may also contribute to re-colonization of a patient. It was shown in one of our cases to originate from an electric shaver which was not disinfected at all. MRSA may survive on inanimate surfaces and cotton for more than 90 days 26. Even making the bed leads to a large increase of MRSA in the air for 15 minutes 27. Careful disinfection of these possible sources and changing linen after the antiseptic treatment is therefore crucial to ensure prevention of re-colonization as recommended in the German guideline on MRSA patients 13.

Identification of MRSA was not carried out for all screening swabs in one laboratory but with the same test method. Differences in the sensitivity and specificity have been described 282930 which may have an impact on the identification of a MRSA patient. But it is unlikely to have an impact on the result of the antiseptic treatment because the method would have been the same before and after treatment of the same patient. That is why it was justified not to carry out the identification of MRSA in one specific laboratory especially because recent data indicate that determination of phenotypic resistance may largely underestimate the genotypic resistance in MRSA 31.

Another finding is the good dermal tolerance of the antiseptic soap. All 35 patients tolerated repetitive use of the preparation very well, even more than one treatment cycle. Another preparation (Octenisept) has been described to lead to skin redness in 4 of 28 patients resulting in termination of the treatment 25. The excellent dermal tolerance of Stellisept scrub on intact and scarified skin has been described before 32.

Stellisept scrub in combination with nasal mupirocin was found to effectively and progressively eradicate MRSA from colonized patients. Antiseptic treatment may have to be repeated.

GK designed the study, organized the participating hospitals, collected the data and analyzed them. AK participated in the design of the study and in the analysis of data. Both authors read and approved the final manuscript.