Chronic nasal Staphylococcus aureus carriage identifies a subset of newly diagnosed granulomatosis with polyangiitis patients with high relapse rate.
The aim of this study was to evaluate whether chronic nasal carriage of Staphylococcus aureus (SA) is related to relapses in patients with newly diagnosed ANCA-associated vasculitis (AAV).



In two clinical trials (n = 200), for early systemic (n = 83) and generalized (n = 117) AAV, nasal swabs were obtained monthly and at the time of a relapse. Chronic nasal SA carriage (CNSAC) was defined as ⩾ 75% of cultures being SA positive, with non-carriers being SA negative in all cultures and remaining patients being intermittent carriers. Fifty-five of 200 (27.5%) patients received prophylactic trimethoprim/sulfamethoxazole (T/S) against Pneumocystis jirovecii .



Of the total AAV patients, 24/200 (12%) were chronic, 102/200 (51%) intermittent and 74/200 (37%) non-carriers. Of 65 relapsing patients, 10/24 (41.7%) were chronic, 32/102 (31.4%) intermittent and 23/74 (31.1%) non-carriers (P = 0.59). For all AAV patients, CNSAC was not associated with an increased relapse risk [odds ratio (OR) = 1.57, 95% CI: 0.66, 3.76; P = 0.31]. However, 23/24 chronic carriers had granulomatosis with polyangiitis (GPA). In the 73 patients with generalized GPA (hazard ratio = 4.10, 95% CI: 1.37, 12.25; P = 0.01) and the 78 patients with early systemic GPA during immunosuppression (hazard ratio = 2.73, 95% CI: 0.95, 7.87; P = 0.06), relapse rates were higher for chronic SA carriers. Prophylactic T/S was not associated with a reduced relapse risk (OR = 0.71, 95% CI: 0.36, 1.41; P = 0.33). Nevertheless, prophylactic T/S reduced CNSAC (OR = 0.19, 95% CI: 0.04, 0.91; P = 0.04).



The frequency of CNSAC in newly diagnosed GPA paralleled that in the general population. This subset of GPA patients (23/151, 15.2%) has a high relapse rate despite immunosuppression and prophylactic T/S treatment, requiring further investigations on pathogenesis and therapy.
Department of Internal Medicine, Vaasa Central Hospital, Vaasa, Finland.
Anna
A
Salmela
Department of Biochemistry and Immunology, Statens Seruminstitut, Copenhagen, Denmark.
Niels
N
Rasmussen
Department of Immunology, Maastricht University, Maastricht, The Netherlands.
Jan Willem Cohen
JWC
Tervaert
Department of Medicine, University of Cambridge, Cambridge, UK.
David R W
DRW
Jayne
Abdomen Center, Nephrology, Helsinki University Hospital, Helsinki, Finland.
Agneta
A
Ekstrand
D000293:Adolescent; D000328:Adult; D000368:Aged; D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000188:drug therapy / Q000382:microbiology; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000378:metabolism; D002908:Chronic Disease; D005260:Female; D014890:Granulomatosis with Polyangiitis / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009666:Nose / Q000382:microbiology*; D011446:Prospective Studies; D012008:Recurrence; D013048:Specimen Handling; D013203:Staphylococcal Infections; D013211:Staphylococcus aureus / Q000302:isolation & purification; D055815:Young Adult
D019268:Antibodies, Antineutrophil Cytoplasmic
Staphylococcus aureus; chronic nasal carriage; disease activity; disease severity; granulomatosis with polyangiitis; microscopic polyangiitis; nasal culture; relapse; trimethoprim/sulfamethoxazole; vasculitis