MRSA

• synonyms: staph, Staphylococcus aureus, staph aureus, MRSA
• may be hospital acquired (HA) or community associated (CA).
• infections include skin, osteomyelitis, septic arthritis, endocarditis, meningitis, pneumonia
• can be spread by direct contact, towels, sheets, wound dressings, clothes, workout areas, sports equipment, whirlpools
• MRSA most often affects elbows and knees
• Often appears as large, tender, aggresive pustule with an erythematous ring 
• Associated with contact sports: football, wrestling, rugby. Often develops from simple abrasions.
• Risk factors: artificial turf, skin abrasion, shaving of skin, sharing towels or equipement, high body mass index, improperly cleaned team whirlpools.
• Diagnosed by wound culture with antibiotic susceptibilities
• Treatment = Incision and drainage and antibiotics
• Empiric Treatment: Bactrim DS 1tab PO BID (8-12mg TMP/40-60SMX per kg/day divided BID for Peds); Doxyxycline 100mg PO BID(do not use in peds); Clindamycin 300-450mg PO QID (10-20mg/kg/day divided QID for PEDS); consider adding rifampin.
• Definitive antiobiotic treatment should be based on culture susceptibilities, consider Infectious disease consultation when available.
• HA-MRSA first line antibiotics: Vancomycin, consider gentamicin or rifampin for synergy. Other agents = daptomycin, linexolid, tigecycline, bactrim.
• CA-MRSA first line antibiotics: doxycycline or clindamycin, or bactrim.
• MRSA Prevention: no equipement sharing between players, no sharing towels, routine cleaning of all whirlpools / shared resources, athletes should pre-scrub with chlorhexidine soaps prior to whirlpool use, all open wounds should be occlusively dressed during practice and games, 
• MRSA Osteomyelitis in Children: 4 independent predictors (temperature > 38.0 C, white blood-cell count > 12000 cells/µL, hematocrit < 34%, and C-reactive protein > 13 mg/L) can differentiate between MRSA and MSSA osteomyelitis. The predicted probability of MRSA osteomyelitis is 92% if all 4 predictors are present, 45% if 3 are present, 10% if 2 are present, 1% if 1 predictor is present.  (Ju KL, J Bone Joint Surg Am. 2011 Sep 21;93(18):1693-701).

Preoperative screening for MRSA (MRSA Screening)

• nasal cultures may be performed by swabbing a sterile saline solution-moistened polyester (Dacron) swab for 5 seconds along the interior naris. 
• 22.6% of patients are MSSA carriers; 4.4% are MRSA carriers. (Kim DH, JBJS 2010;92:1820)
• MRSA SSI occurrs in 8% of MRSA-positive and in only 0.61% of the MRSA-negative patients. odds ratio of 14.2 (P = 0.02). (Thakkar V, Ghobrial GM, Maulucci CM, Singhal S, Prasad SK, Harrop JS, Vaccaro AR, Behrend C, Sharan AD, Jallo J. Nasal MRSA colonization: impact on surgical site infection following spine surgery. Clin Neurol Neurosurg. 2014 Oct;125:94-7.)

MRSA Decolinization

• MRSA & MSSA decolinization = intranasal 2% mupirocin ointment (Bactroban) applied to the interior of each naris twice daily for 5 days and shower wash with 2% clorhexidine daily for 5 days.
  -eradication may reduce infection rates from 0.45% without eradication to 0.19% with eradication.  (Kim DH, JBJS 2010;92:1820)
• If MRSA carrier, vancomycin used as perioperative prophylactic antibiotic.  Vancomycin 15mg/kg started in holding and completed prior to beginning of procedure, with cefazolin 2 or 3 grams at time of “time-out”.
• MRSA carriers (anterior nares) are 2-9 times more likely to develop surgical site infections than noncarriers
• Consider pre-op for: immunocompromised, recent nursing home/hospital admission, antibiotic exposure within 1 yr.
• Options: Chorhexicine 2% topical wash QD for 3-7 days: Doxycycline 100mg PO BID x 7 days: Mupirocin 1cm applied to nares TID for 5-7 days: Providone-Iodine 5% 4x per day for 5 days: Rifampin 300mg PO BID x7days.
• Larkin S, Orthopedics 2008;31:37

MRSA Return to Play - Sports

• Athletes can return to contact sports when no new lesions develop for 48 hours and they have been treated with antibiotics for 72 hours. (OKU-11)
•  All wounds must be covered with bioocclusive prewrap and tape. 

• Kirkland EB, Adams BB. Methicillin-resistant Staphylococcus aureus and athletes. J Am Acad Dermatol. 2008 Sep;59(3):494-502. 

• Rihn JA, Michaels MG, Harner CD. Community-acquired methicillin-resistant staphylococcus aureus: an emerging problem in the athletic population. Am J Sports Med. 2005 Dec;33(12):1924-9.