We assessed methicillin-resistant Staphylococcus aureus (MRSA) in persons on 49 swine farms in Belgium. Surveys showed that 48 (37.8%) persons carried MRSA ST398 and 1 (0.8%) had concurrent skin infection. Risk factors for carriage were MRSA carriage by pigs, regular contact with pigs and companion animals, and use of protective clothing.

Mupirocin was used in haemodialysis patients in an attempt to eradicate nasal carriage of Staphylococcus aureus and to prevent infection caused by this microorganism. The effectiveness of calcium mupirocin as a 2% nasal ointment OB2 (16 patients for 104 patient-months) was compared to that of placebo (18 patients for 147 patient-months) in a double-blind study. Mupirocin or placebo were applied in both anterior nares thrice daily for 2 weeks and subsequently three times weekly for a total of 9 months. During therapy, S. aureus was recovered from only 6% of the nasal cultures in the mupirocin group compared to 58% in the placebo group (P less than or equal to 0.01). Only one S. aureus infection was documented in the mupirocin group compared to six in the placebo group (P less than or equal to 0.05). The S. aureus strain causing the single infection in the mupirocin group was of a different phage type to that of the original nasal strain. In contrast, at least four of the six strains causing infection in the placebo group were of similar phage type to the original nasal strain. All S. aureus isolates remained mupirocin sensitive (MIC less than or equal to 1 mg/l). In conclusion, mupirocin nasal ointment was effective in eradicating nasal carriage of S. aureus and in preventing S. aureus infections in patients on haemodialysis.

The incidence of bacteraemia in relation to the degree of transfusional iron overload was studied prospectively in patients from one haemodialysis unit over a 2-year period, with a total follow-up of 181.3 patient-years in 158 patients. Every 3 months, the patients were classified according to the serum ferritin in one of three groups: less than 500, 500-1000 or greater than 1000 micrograms/l. Twenty-nine episodes of bacteraemia were recorded over 181.3 patient-years (yearly incidence of 0.160). The yearly incidence of bacteraemia was 0.1173 and 0.1101 for ferritin less than 500 and 500-1000 micrograms/l (no significant difference), with a cumulative incidence for both groups of 0.1164. In the ferritin greater than 1000 micrograms/l group, the incidence was 0.3404 (P less than or equal to 0.005 versus the ferritin less than or equal to 1000 micrograms/l group). After stratification for patient's age (at inclusion in the study) and duration of haemodialysis therapy, the higher incidence of bacteraemia in the ferritin greater than 1000 versus less than or equal to 1000 micrograms/l groups persisted (P less than or equal to 0.005). This prospective study confirms previous retrospective studies in showing that acquired transfusional iron overload in haemodialysis is associated with a greater risk of bacteraemia.

A point prevalence culture survey was carried out to investigate the prevalence of fecal carriage of vancomycin-resistant enterococci (VRE) among patients admitted to an 800-bed general hospital where no VRE had been isolated previously. Twenty-two of 636 patients (3.5%) were found to be VRE carriers. Eighteen strains were identified as Enterococcus faecium, three were identified as Enterococcus gallinarum, and one was identified as Enterococcus faecalis. The susceptibilities of the enterococci to ampicillin, vancomycin, and teicoplanin were determined by the disk diffusion and the agar dilution methods. High-level resistance (HLR) to gentamicin and streptomycin was determined by the agar screening method. Eighteen strains (82%) were highly resistant to vancomycin, and four strains (18%) were moderately resistant to vancomycin. Five strains were susceptible to teicoplanin (23%; MICs, <8 g/ml). Only one strain (4.5%, E. faecium) showed HLR to gentamicin, and six strains (27%) showed HLR to streptomycin (one E. faecalis and five E. faecium strains). All 18 E. faecium and 1 E. faecalis strain carried the vanA gene, and 3 E. gallinarum strains carried the vanC gene. An epidemiological investigation revealed several risk factors for VRE colonization: hospitalization and duration of stay in the hematology department and prior vancomycin treatment. The study demonstrates that the patient's gastrointestinal tract is a possible reservoir for VRE, even in hospitals where VRE infections have not yet been observed. Therefore, we conclude that infection control precautions and restriction of glycopeptide usage may be key issues in limiting the emergence and spread of nosocomial VRE infections.

The susceptibility of anaerobic bacteria remains stable in Belgium, except for clindamycin, which shows a continuous decrease in activity. However, for each of the tested antibiotics, at least a few resistant organisms were detected. Consequently, for severe infections involving anaerobic bacteria, it could be advisable to perform microbiological testing instead of relying on known susceptibility profiles. Periodically monitoring background susceptibility remains necessary to guide empirical therapy.