Methicillin resistance of airborne coagulase-negative staphylococci in homes of persons having contact with a hospital environment.

BACKGROUND

The persons having contact with a hospital environment (hospital personnel workers and discharged patients) are highly exposed to colonization with multidrug-resistant bacteria. The aim of this study was to evaluate the airborne Staphylococcus genus features in homes in which inhabitants have had contact with the hospital environment.

METHODS

Airborne bacteria were collected using a 6-stage Anderson impactor. The Staphylococcus species composition and resistance to methicillin, and other antimicrobial agents among 3 coagulase-negative staphylococci (CNS) species (S cohnii spp cohnii, S epidermidis, S hominis), were determined. Antibiotic resistance of isolates was tested using the agar screen method with methicillin, the polymerase chain reaction technique to detect the mecA gene, and the disk diffusion method.

RESULTS

A higher prevalence of methicillin-resistant (MR) strains among the species isolated (40% of S epidermidis, 40% of S hominis, and 60% of S cohnii spp cohnii) was found in homes of persons who had contact with a hospital environment compared with the reference homes (only 12% of S hominis). The mecA gene was revealed in all MR S epidermidis strains and in some MR S hominis (50%) and S cohnii spp cohnii (33%) strains. All isolated MR CNS strains were susceptible to vancomycin, rifampicin, and linezolid.

CONCLUSION

High numbers of airborne multidrug-resistant MR CNS in the homes of persons having contact with a hospital environment indicates that such inhabitants pose a risk of intrafamilial spreading of MR strains via air.