Staphylococcal Carriage in a Hospital Population: Throat VS. Nasal Carriage and Persistence of Nasal Carriage

Seven groups, involving 391 medical personnel and patients, were studied with regard to nasal carriage of Staphylococcus aureus. Six of these groups were also studied for throat carriage. The incidence of throat carriage in 5 of 6 groups either equaled or exceeded nasal carriage, and 15% of the upper respiratory carriers would have been missed had not the throat been examined. The Chi-square test of significance indicated no differences between groups with regard to the incidence of total nasal carriage, total throat carriage, simultaneous nasal and throat carriage, or carriage in the nose alone; only for carriage in the throat alone did the differences approach significant levels. Throat carriage appeared to be independent of nasal carriage in 53% of those carrying staphylococci in the throat, either by virtue of a negative nasal culture or a different phage type in the nose; there were also differences in the distribution of phage groups isolated from each site. A proposed classification where arbitrarily selected rates were used to determine an individual's persistence of carriage appeared to be more applicable than the binomial distribution method. (Author)