Dispersal ofStaphylococcus aureusInto the Air Associated With a Rhinovirus Infection

Objective:

To determine whether healthy adult nasal carriers ofStaphylococcus aureuscan disperseS. aureusinto the air after rhinovirus infection.

Design:

We investigated the “cloud” phenomenon among adult nasal carriers ofS. aureusexperimentally 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 forS. 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 ofS. aureusfor 4 or 8 weeks.

Results:

After rhinovirus inoculation, dispersal ofS. aureusinto the air increased 2-fold with peak increases up to 34-fold. Independent predictors ofS. aureusdispersal included the time period after rhinovirus infection and wearing street clothes (P< .05). Wearing barrier garb but not a mask decreased dispersal ofS. aureusinto the air (P< .05).

Conclusion:

Virus-induced dispersal ofS. aureusinto the air may have an important role in the transmission ofS. aureusand other bacteria.

An outbreak of mupirocin-resistant Staphylococcus aureus on a dermatology ward associated with an environmental reservoir

OBJECTIVE

To investigate a cluster of mupirocin-resistant Staphylococcus aureus on a dermatology ward.

DESIGN

An outbreak of mupirocin-resistant S aureus was noted on the dermatology ward during a prospective epidemiologic study of methicillin-resistant S aureus (MRSA) and borderline methicillin-susceptible S aureus (BMSSA). Pulsed-field gel electrophoresis (PFGE) of whole-cell DNA digested with Sma I was used as a marker of strain identity.

SETTING AND PATIENTS

An 850-bed university hospital with a 12-bed inpatient dermatology ward. Most patients have severe, exfoliating dermatologic disorders.

RESULTS

MRSA or BMSSA were isolated from 13 patients on the dermatology ward over a 14-month period. Eleven of these isolates (84.6%) were mupirocin-resistant. Nine isolates were present on admission (81.8%); 8 of these patients had been hospitalized on the same ward within the last two months. Nasal and hand cultures from 36 personnel were negative for mupirocin-resistant MRSA or BMSSA. Extensive environmental culturing revealed that a blood pressure cuff and the patients' communal shower were positive for mupirocin-resistant BMSSA. PFGE of all mupirocin-resistant isolates demonstrated that the nine patients and both environmental sources had identical DNA typing patterns.

INTERVENTIONS

Changing of blood pressure cuffs between patients and more stringent cleaning of communal areas was initiated. Repeat environmental cultures were negative.

CONCLUSIONS

S aureus is not usually associated with an environmental reservoir; however, these patients all had severe desquamation, which may have prolonged environmental contamination.