Reclassification of Staphylococcus aureus nasal carriage types.
BACKGROUND
Persistent nasal carriers have an increased risk of Staphylococcus aureus infection, whereas intermittent carriers and noncarriers share the same low risk. This study was performed to provide additional insight into staphylococcal carriage types.


METHODS
Fifty-one volunteers who had been decolonized with mupirocin treatment and whose carriage state was known were colonized artificially with a mixture of S. aureus strains, and intranasal survival of S. aureus was compared between carriage groups. Antistaphylococcal antibody levels were also compared among 83 carriage-classified volunteers.


RESULTS
Persistent carriers preferentially reselected their autologous strain from the inoculum mixture (P=.02). They could be distinguished from intermittent carriers and noncarriers on the basis of the duration of postinoculation carriage (154 vs. 14 and 4 days, respectively; P=.017, by log-rank test). Cultures of swab samples from persistent carriers contained significantly more colony-forming units per sample than did cultures of swab samples from intermittent carriers and noncarriers (P=.004). Analysis of serum samples showed that levels of immunoglobulin G and immunoglobulin A to 17 S. aureus antigens were equal in intermittent carriers and noncarriers but not in persistent carriers.


CONCLUSIONS
Along with the previously described low risk of infection, intermittent carriers and noncarriers share similar S. aureus nasal elimination kinetics and antistaphylococcal antibody profiles. This implies a paradigm shift; apparently, there are only 2 types of nasal carriers: persistent carriers and others. This knowledge may increase our understanding of susceptibility to S. aureus infection.
Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands.
Alex
A
van Belkum
Nelianne J
NJ
Verkaik
Corné P
CP
de Vogel
Hélène A
HA
Boelens
Jeroen
J
Verveer
Jan L
JL
Nouwen
Henri A
HA
Verbrugh
Heiman F L
HF
Wertheim
D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000907:Antibodies, Bacterial / Q000097:blood; D002353:Carrier State / Q000145:classification* / Q000188:drug therapy / Q000276:immunology / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016712:Mupirocin / Q000494:pharmacology; D009297:Nasal Mucosa / Q000382:microbiology*; D009824:Ointments; D013203:Staphylococcal Infections / Q000145:classification* / Q000188:drug therapy / Q000276:immunology; D013211:Staphylococcus aureus / Q000145:classification / Q000276:immunology / Q000302:isolation & purification*; D055815:Young Adult
D000900:Anti-Bacterial Agents; D000907:Antibodies, Bacterial; D009824:Ointments; D016712:Mupirocin