Validation of self-administered nasal swabs and postage for the isolation of Staphylococcus aureus

Abstract

Staphylococcus aureus carriers are at higher risk of S. aureus infection and are a reservoir for transmission to others. Detection of nasal S. aureus carriage is important for both targeted decolonization and epidemiological studies. Self-administered nasal swabbing has been reported previously, but the effects of posting swabs prior to culture on S. aureus yield have not been investigated. A longitudinal cohort study was performed in which healthy volunteers were recruited, trained in the swabbing procedure and asked to take weekly nasal swabs for 6 weeks (median: 3 weeks, range 1–6 weeks). Two swabs were taken at each sampling episode and randomly assigned for immediate processing on arrival to the laboratory (Swab A) or second class postage prior to processing (Swab B). S. aureus was isolated using standard methods. A total of 95 participants were recruited, who took 944 swabs (472 pairs) over a median of 5 weeks. Of these, 459 swabs were positive for S. aureus. We found no significant difference (P=0.25) between 472 pairs of nasal self-swabs processed immediately or following standard postage from 95 study participants (51.4 % vs. 48.6 %, respectively). We also provide further evidence that persistent carriers can be detected by two weekly swabs with high degrees of sensitivity [92.3 % (95 % CI 74.8–98.8 %)] and specificity [95.6 % (95 % CI 84.8–99.3 %)] compared with a gold standard of five weekly swabs. Self-swabbing and postage of nasal swabs prior to processing has no effect on yield of S. aureus, and could facilitate large community-based carriage studies.

Nasal microbiome disruption and recovery after mupirocin treatment in Staphylococcus aureus carriers and noncarriers

“…To enhance study participation, we adopted a selfsampling strategy which allowed participants to send in samples through regular mail service. This method has been found appropriate for detection of S. aureus previously 21,22 . Nevertheless, delayed transport caused 20% of samples to be processed > 48 h after sampling.…”

Nasal microbiome research in ANCA-associated vasculitis: Strengths, limitations, and future directions

“…Collection by nasal brushes should be the preferred method, as investigations have shown a significant reduction in phylogenetic diversity by nasal washes [41] . Procession of nasal swabs after standard postage of study participants may not influence the yield of specific bacteria ( S. aureus ) in comparison to immediate procession [42] . Other investigations found that storage at room temperature for 14 days led to an undesired S. aureus growth.…”

Colonization and transmission of Staphylococcus aureus in schools: a citizen science project

“…To this end, we carried out a pilot study on the carriage of S. aureus within two secondary schools (specifically year groups 7–10 corresponding to pupils aged 10–15 years old) in England between March 2018 and July 2019. Colonization status of participating pupils was ascertained through self-administered nasal swabs [ 22 ] from which isolates were cultured and sequenced. Taking a public engagement approach that has previously delivered exceptionally high participation rates of >90 % [ 23–26 ], we recruited classes within our study schools as citizen scientists to inform the design and delivery of our study within their own school.…”

“…To this end, we carried out a pilot study on the carriage of S. aureus within two secondary schools (specifically year groups 7-10 corresponding to pupils aged 10-15 years old) in England between March 2018 and July 2019. Colonization status of participating pupils was ascertained through self-administered nasal swabs [22] from which isolates were cultured and sequenced. Taking a…”