Background/Purpose: Infection with methicillin-resistant Staphylococcus aureus (MRSA) is a source of significant morbidity/mortality.  Health-care entities spend large amounts to prevent spread of MRSA.  Most MRSA colonization literature is for surgical inpatients, with little exploration of the possible influence of immune-modifying drugs on colonization.  These drugs are being used more commonly in treatment of chronic conditions, such as rheumatologic diagnoses.  This study attempted to identify the influence of Tumor Necrosis Factor inhibitor (anti-TNF) drugs on MRSA carrier state in patients with diagnoses of psoriasis, psoriatic arthritis, rheumatoid arthritis, or ankylosing spondylitis.

Colonization with MRSA leads to greater risk of infection with MRSA.  Screening and intervention decrease blood borne infections, leading to use of screening programs.  Studies in various environments have attempted to describe the carriage rate for MRSA, now estimated to be 1.2- 14%.

There has been some investigation into the relationship between MRSA colonization and immunosuppression, but it has been limited to transplant patients, cancer patients, and those with HIV.  Currently there are no data on the relationship between immunosuppresive drugs and MRSA colonization in those being treated for rheumatologic conditions and psoriasis.

Methods: Medical records of patients admitted to two large referral hospitals between 1/1/07 and 3/31/10 were reviewed. All admitted patients 18 years and older with psoriasis, psoriatic arthritis, rheumatoid arthritis, or ankylosing spondylitis during this period were included for retrospective chart review (1001 persons).  Of these, 436 were screened for nasal MRSA during the study period.  Demographics, comorbidities and length of stay were noted as was information on treatment of their conditions and MRSA screen result.  The rate in this group was compared to known MRSA rate for all patients screened in the two hospitals for the period (6.7%).

Results: Records from 436 patients were used; 10 (2.3%) had psoriatic arthritis, 15 (3.4%) had ankylosing spondylitis, 72 (16.5%) had psoriasis, and 341 (78.2%) had rheumatoid arthritis.  MRSA colonization was noted for 53 (12.2%) patients, which is much higher than the overall rate of 6.7% for adults.  A TNF inhibitor was in the medical regimen for 54 (12.4%) patients. Of those prescribed anti-TNF drugs, 11.1% were MRSA positive.  The study population with MRSA tended to have a longer length of stay (p = 0.0529), and come from a nursing home (27.5%).  There was a strong association between nursing home residence and MRSA result (p = 0.0003).

Conclusion: Patients with psoriasis and rheumatologic conditions had a higher rate of MRSA colonization than the general patient population at these referral centers.  Patients treated with anti-TNF drugs were no more likely than those being treated with traditional immune modulating agents to have a positive MRSA screen.  Those patients coming to the hospital from a nursing facility were more likely to have a positive MRSA screen.

---

« Back to 2012 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/exploring-the-relationship-of-anti-tumor-necrosis-factor-drugs-and-methicillin-resistant-staphylococcus-aureus-nasal-colonization-in-patients-with-rheumatologic-conditions-and-psoriasis/