Dispersal of Staphylococcus aureus into the air associated with a rhinovirus infection.

OBJECTIVE: To determine whether healthy adult nasal carriers of Staphylococcus aureus can disperse S. aureus into the air after rhinovirus infection. DESIGN: We investigated the "cloud" phenomenon among adult nasal carriers of S. aureus experimentally infected with a rhinovirus. Eleven volunteers were studied for 16 days in an airtight chamber wearing street clothes, sterile garb, or sterile garb plus surgical mask; rhinovirus inoculation occurred on day 2. Daily quantitative air, nasal, and skin cultures for S. aureus; cold symptom assessment; and nasal rhinovirus cultures were performed. SETTING: Wake Forest University School of Medicine, Winston-Salem, North Carolina. PARTICIPANTS: Wake Forest University undergraduate or graduate students who had persistent nasal carriage of S. aureus for 4 or 8 weeks. RESULTS: After rhinovirus inoculation, dispersal of S. aureus into the air increased 2-fold with peak increases up to 34-fold. Independent predictors of S. aureus dispersal included the time period after rhinovirus infection and wearing street clothes (P < .05). Wearing barrier garb but not a mask decreased dispersal of S. aureus into the air (P < .05). CONCLUSION: Virus-induced dispersal of S. aureus into the air may have an important role in the transmission of S. aureus and other bacteria.

Airborne dispersal as a novel transmission route of coagulase-negative staphylococci: interaction between coagulase-negative staphylococci and rhinovirus infection.

OBJECTIVE: To investigate whether rhinovirus infection leads to increased airborne dispersal of coagulase-negative staphylococci (CoNS). DESIGN: Prospective nonrandomized intervention trial. SETTING: Wake Forest University School of Medicine, Winston-Salem, North Carolina. PARTICIPANTS: Twelve nasal Staphylococcus aureus-CoNS carriers among 685 students screened for S. aureus nasal carriage. INTERVENTIONS: Participants were studied for airborne dispersal of CoNS in a chamber under three conditions (street clothes, sterile gown with a mask, and sterile gown without a mask). After 2 days of pre-exposure measurements, volunteers were inoculated with a rhinovirus and observed for 14 days. Daily quantitative nasal and skin cultures for CoNS and nasal cultures for rhinovirus were performed. In addition, assessment of cold symptoms was performed daily, mucous samples were collected, and serum titers before and after rhinovirus inoculation were obtained. Sneezing, coughing, and talking events were recorded during chamber sessions. RESULTS: All participants had at least one nasal wash positive for rhinovirus and 10 developed a symptomatic cold. Postexposure, there was a twofold increase in airborne CoNS (P = .0004), peaking at day 12. CoNS dispersal was reduced by wearing a gown (57% reduction, P < .0001), but not a mask (P = .7). Nasal and skin CoNS colonization increased after rhinovirus infection (P < .05). CONCLUSIONS: We believe this is the first demonstration that a viral pathogen in the upper airways can increase airborne dispersal of CoNS in nasal S. aureus carriers. Gowns, gloves, and caps had a protective effect, whereas wearing a mask did not further reduce airborne spread.