[Investigations into the use of respiratory masks for reducing the MRSA-exposure of veterinarians visiting regularly pig herds--first experiences].

The study presents first experiences on the controlled use of respiratory masks against Methicillin-resistant Staphylococcus aureus (MRSA) in a multi-person veterinary pig practice. Seven veterinarians entered the trial (five wearing masks, two wearing no masks) after the veterinarians had performed a decolonisation protocol. The pig herds were visited regularly by the veterinarians during the study period. The five "trial" veterinarians wore gloves and respiratory masks for at least 30 days and 30 farm visits. The two "control" veterinarians wore gloves only. Nasal swabs were collected at a seven day interval. Swabs and ten masks per "trial" veterinarian were bacteriologically tested for MRSA including MLST- and spa-typing. The study showed a high MRSA-exposure for the veterinarians, since 68% of the masks were tested positive for MRSA. However, four vets stayed MRSA-negative while using the masks. Only one of the"trial" veterinarians became positive after two weeks. After the masks were not worn any more, two veterinarians returned to colonisation soon again. The two "control" veterinarians turned positive after 26 and 54 days, respectively. The high finding-rates of MRSA in the masks proof an enormous risk of nasal colonisation during routine work.The results of our study do not proof the potential of respiratory masks to prevent nasal colonisation of veterinarians with MRSA. However, there are no hints, that the proper use of masks could be a risk factor for becoming colonised. Further details of the proper use of masks and the quantification of their protective potential need further studies on a larger scale.