MRSA Background. New Challenges From an Old Foe. MRSA Demographics. Comparison of Types of MRSA CA-MRSA HA-MRSA

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1 Winter Clinical 2017 : MRSA Update Whitney A. High, MD, JD, Meng whitney.high@ucdenver.edu Associate Professor, Dermatology & Pathology Director of Dermatopathology University of Colorado School of Medicine January 2017 Hawaii, Hawaii DISCLOSURE OF RELEVANT RELATIONSHIPS WITH INDUSTRY WHITNEY A. HIGH, MD, JD, MEng MRSA Update I do not have any relevant relationships with industry to disclose. New Challenges From an Old Foe MRSA Background Staph aureus causes most skin and soft tissue infections (SSTI) For decades, Staph aureus was sensitive to dicloxacillin and cephalexin 1961 MRSA first recognized Divided into: hospital acquired (HA-MRSA) community acquired (CA-MRSA) Comparison of Types of MRSA CA-MRSA HA-MRSA Younger patients Older patients MRSA Demographics Countries with highest prevalence of CA-MRSA: United States Japan Skin & soft tissue Isolated β-lactam resistance Often produces exotoxin (PVL) Generally systemic Multidrug resistance Usually no exotoxins Important dates in CA-MRSA history in USA: MRSA outbreak in IVDA in Detroit four fatalities due to CA-MRSA in kids Latter strain (USA300) has come to predominate Saravolatz et al. Ann Intern Med Gardam et al. Can J Infect Dis

2 MRSA American Exceptionalism PVL may be less important, speg may be more important PVL may be less important, speg may be more important Just how common is MRSA? Differs among healthcare settings California ED study (2006) - 59% isolates SSTI Florida OP derm clinic (2008) - 14% isolates SSTI Nashville ED 2001 drained ~150 abscesses/year 2007 drained ~1800 abscesses/year (80% MRSA) 2014 Sentinel Study 6 dermatology centers, 5 states overall incidence of MRSA = 29.4% of isolates CA (38%), TX (33%), AL (31%), AZ (19%), FL (11%) Who gets MRSA? Athletes some of the earliest cases of USA300 were reported in a college football team in Pennsylvania Prisoners other early reports of the same USA300 strain were described in prisoners in Mississippi and California Risk Factors for CA-MRSA Children Athletes Certain ethnic populations MSM & HIV pts IVDA pts Prisoners Military personnel Travelers (you) People in contact with travelers (you) Healthcare workers (you) Recent problems on sports teams across the USA 2

3 Even legal consequences of MRSA January 2016 How CA-MRSA presents? Abscess or furuncle most common Often on extremities (66% on legs) May be mistaken for spider bite May have a surrounding cellulitis Less often: papules and pustules (folliculitis, 7-20%) crusted plaques (impetigo, 3-30%) reports of otitis externa & paronychia Spiders are alleged to do amazing things Real spider bite Real spider bite 24 hours 4 days 24 hours 4 days 3

4 How to treat it! Single abscess may respond to I&D alone cruciate/punch incision, no packing I&D alone cured 87% in one study* (vs. 95%) Still responsive to TMP/SMX, DCN susceptibility to DCN seems durable (~95%/5yr period) Clindamycin resistance (regional, inducible) Consider addition of rifampin (intracellular killing) Decolonization efforts: topical agents, avoid shared soap, towels, towel bars? dilute bleach, BPO soaps, Zn shampoo? Cohen PR, Int J Dermatol. 2007; 46:1-11. Ruhe et al. CID I&D alone probably adequate for most singular abscesses (<5 cm) Packing not typically necessary Systemic antibiotics for those with : multiple lesions rapid disease progression associated cellulitis immunosuppression, extremes of age, or complex medical hx abscess in difficult area (e.g., face, hands, or genitalia) recurrent abscess Notions that patients with larger lesions, surrounding cellulitis, fever, or coexisting conditions particularly benefit from treatment with adjunctive antibiotics are speculative. Tropical MRSA ecthyma 4

5 2.5 year old boy failed 2 courses of cephalexin Community MRSA Blossoming ClindamycinInducible Resistance November 2016 Nature, July 2016 Recognize Complicated Infections Complicating factors: fever, tachycardia, tachypnea, hypotension persons at extremes of age, immunocompromised, etc. may well require intravenous antibiotic Latter may require: vancomycin, daptomycin, linezolid, tedizolid, ceftaroline, dalbavancin, oritavancin, telavancin, and quinupristin-dalfopristin. 5

6 Other Antibiotics for Complicated Infections/Situations Glycopeptides 1 st gen vancomycin 2 nd gen dalbavancin (2 doses a week apart) 2 nd gen - ortavancin (OTD) Oxazolidinones 1 st gen - linezolid (BID, longer course) 2 nd gen - tedizolid (qd, shorter course, side fx) Recurrent Staph Infections In practice, other antibiotics effective for MRSA, and cost less, should be considered first. Why is this a problem? Eradication Therapies Controversial (Cochrane insufficient evidence ) Some % of patients cannot be cleared Oral antibiotics (rifampin/dcn) + topicals Chlorhexidine (P-I, triclosan, tea tree oils) Intranasal mupirocin (BID x 5d) mupirocin resistance on rise (? up to 50%!!!) retapamulin ointment, bacitracin ointment Project CLEAR Allergic Contact Dermatitis From Tea Tree Oil AMBER STONEHOUSE, MD & JAMES STUDDIFORD, MD Consultant. Vol. 47 No. 8 - July 1, 2007 Serial decolonization lasted 6-months, - nasal mupirocin BID, chlorhexidine mouthwash BID, 4% chlorhexidine in shower or bath qd. Researchers found: All comers 30% reduction in MRSA infection 16% reduction in all-cause infection for 1 year Fully compliant 44% reduction in MRSA infection 40% reduction in all-cause infection in 1 year Melaleuca alternifolia Broad antiseptic properties ACD in about 5-10% Cross rxn with benzoin 6

7 Mupirocin Resistance First reported in 1987 (in use since 1985) June 2015, NYC Classically divided into: low-level and high-level resistance thought that high level resistance was rare (2%) Isolated reports of up to 50+% of isolates resistant in some areas Almost certainly related to mupirocin use N=247, May 2012 to September % of isolates resistant to mupirocin Risk factors - MRSA and atopic dermatitis 2014, Houston 9.5% resistance retapamulin 9.8% resistance mupirocin 14% resistance to chlorhexidine Resistance correlated with MRSA status Bleach Baths Had low incidence of MRSA (7.4% skin, 4% nose) There are some theoretical reasons for MSSA predominance in atopic pts. Excellent response with dilute bleach baths and mupirocin ointment to nares 7

8 Prevalence of MRSA in admitted pedi AD patients increased Prevalence of MSSA in admitted pedi AD patients remained stable Important risk factor for MRSA was a previous hospitalization Costs of misdiagnosis... 30% of ED diagnoses of cellulitis were incorrect Costs of $195M to $515M could be avoided Unnecessary exposure to abx November 2016 Prevention of Infection Hand washing is critical to stop MRSA Hand washing compliance in healthcare settings is typically poor 31.4% compliance with hand washing protocol among 13 derms in two clinics Some studies have shown alcohol rubs/gels (60-95%) may be MORE efficacious than handwashing (as practiced) How are we all acquiring and spreading MRSA? The answer may spoil your vacation. Cohen HA et al. Handwashing patterns in two dermatology clinics. Dermatol Basel Switz April hotel rooms, 6 chains 8

9 Staphyloccocus aureus in 34/35 homes MRSA in 9/35 homes Highest predictor of MRSA in home? October 2013 Reversion to MSSA Staphyloccocus aureus in 34/35 homes MRSA in 9/35 homes Highest predictor of MRSA a cat! 10 years 215 patients 30% with one reversion 25% reverted for remainder of the study period Better re-culture with additional episodes! 9