To determine whether healthy adult nasal carriers of Staphylococcus aureus can disperse S. aureus into the air after rhinovirus infection.

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.

Wake Forest University School of Medicine, Winston-Salem, North Carolina.

Wake Forest University undergraduate or graduate students who had persistent nasal carriage of S. aureus for 4 or 8 weeks.

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).

Virus-induced dispersal of S. aureus into the air may have an important role in the transmission of S. aureus and other bacteria.

To investigate whether rhinovirus infection leads to increased airborne dispersal of coagulase-negative staphylococci (CoNS).

Prospective nonrandomized intervention trial.

Wake Forest University School of Medicine, Winston-Salem, North Carolina.

Twelve nasal Staphylococcus aureus-CoNS carriers among 685 students screened for S. aureus nasal carriage.

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.

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).

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.

To compare the prevalence of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) carriage among injection drug users (IDUs) treated in an injection heroin maintenance program with that among IDUs treated in an oral methadone program, and to determine predictors of S. aureus carriage.

Survey.

Two opiate maintenance programs at a psychiatrie university clinic.

A volunteer sample consisting of 94 (74%) of 127 IDUs treated in an injection opiate maintenance program with at least twice daily injections of heroin, and 70 (56%) of 125 IDUs treated in an oral methadone program.

Addicts treated in the intravenous heroin substitution program had a significantly lower overall rate of S. aureus carriage (37 of 94 [39.4%] vs 42 of 70 [60%]; P = .009) and a significantly lower rate of nasal carriage (21 of 94 [22.3%] vs 30 of 70 [42.9%]; P = .005) than did addicts treated in the oral methadone program. Being treated in the oral methadone program was the only independent predictor of S. aureus carriage (odds ratio, 2.27; 95% confidence interval, 1.19-4.31; P=.012). All S. aureus isolates were susceptible to oxacillin.

The regular use of needles under aseptic conditions did not increase the rate of S. aureus carriage among IDUs. Further studies are necessary to investigate whether the lower rate of S. aureus carriage among IDUs treated with intravenous heroin leads to a lower incidence of S. aureus infections in these patients.

To compare the prevalence of nasal Staphylococcus aureus carriage among outpatients receiving allergen-injection immunotherapy with the prevalence among healthy controls and to determine predictors of nasal S aureus carriage.

Survey.

Allergy clinic of a university hospital.

A volunteer sample consisting of 45 outpatients undergoing desensitization therapy and 84 first- and second-year medical students.

The nasal S aureus carriage rate was significantly higher among patients (46.7%) than among students (26.2%; P=.019). In a multivariate model adjusted for age and gender, the presence of atopic dermatitis or eczema was the only independent predictor of nasal S aureus carriage (odds ratio [OR], 4.4; 95% confidence interval [CI95], 1.2-16.0; P=.02). The only other participant characteristic associated with nasal S aureus carriage was immunotherapy with allergen injections (OR, 1.98; CI95, 0.7-6.0), but this association did not reach statistical significance (P=.23). The probability of nasal S aureus carriage was 88.9% for patients receiving allergen injections and having atopic dermatitis or eczema, and 36.1% for patients receiving allergen injections without atopic dermatitis or eczema.

Patients undergoing desensitization have a higher nasal carriage rate of S aureus. However, factors other than the regular use of needles, and in particular abnormalities related to the atopic constitution of these patients, may predispose this population for S aureus carriage.