The environment of two contiguous surgical wards was examined over a period of twelve months by means of a slit sampler, settle plates and blanket sweep plates. At the same time, nasal swabs were taken each week from the patients and all cases of sepsis examined bacteriologically.
Phage typing of more than 3600 isolations of Staph. aureus showed that there was one predominant strain in the air, bedding, patients' noses and infected wounds.
There was no relationship between the total number of bacteria in the ward air and the numbers of Staph. aureus.
The recovery of large numbers of Staph. aureus from the air at certain periods was associated with a high contamination rate in the blankets and with an increased incidence of staphylococcal sepsis.
Not all nasal carriers of Staph. aureus contaminated their bedding. There was evidence that some patients became nasal carriers of strains of staphylococci previously isolated from their bedding.
Some evidence was obtained that blankets may play a role in the transmission of staphylococci from patient to patient.
This work was supported by a grant from the Australian National Health and Medical Research Council. Our thanks are due to Mrs Elisabeth Bradshaw for her technical assistance and to Prof. John Loewenthal for his interest and for permission to study his wards.