Skin and Soft Tissue Infections: MRSA and Beyond Catherine Liu, M.D. - PDF document

5/28/2013 Skin and Soft Tissue Infections: MRSA and Beyond Catherine Liu, M.D. Assistant Clinical Professor Division of Infectious Diseases University of California, San Francisco Overview • Abscesses • Cellulitis • Recurrent SSTI • Animal Bites • Necrotizing fasciitis • Other SSTI 1

5/28/2013 Case 1 20 y/o M presents with 3 days of an enlarging, painful lesion on his L arm that he attributes to a spider bite T 36.9 BP 118/70 P 82 What is the appropriate management of this patient? A. Incision and drainage alone B. Incision and drainage plus oral anti ‐ MRSA antimicrobial agent C. Oral anti ‐ MRSA antimicrobial agent 2

5/28/2013 Abscesses • Incision and drainage is the primary treatment (AII). – For simple abscesses or boils, I&D alone likely adequate • Do antibiotics provide additional benefit? 100% 80% 60% Clinical cure Antibiotic 40% p=.12 Placebo p=.25 p=.52 20% cephalexin TMP-SMX TMP-SMX 0% Rajendran'07 Duong'09 Schmitz'10 1 Rajendran AAC 2007; 2 Duong Ann Emerg Med 2009; 3 Schmitz G Ann Emerg Med 2010; Liu CID 2011; 52: 285-322 Antibiotic therapy is recommended for abscesses associated with: • Severe, extensive disease, rapidly progressive with associated cellulitis or septic phlebitis • Signs & sx of systemic illness • Associated comorbidities, immunosuppressed • Extremes of age • Difficult to drain area (e.g. face, hand, genitalia) • Failure of prior I&D (AIII) Liu CID 2011; 52: 285 ‐ 322 3

5/28/2013 Microbiology of Purulent SSTIs: ER Patients unknown 9% non ‐ B hemolytic other/ unknown, 15% strep viridans strep, 2% other 4% 8% B ‐ hemolytic coag neg staph, 6% strep B ‐ hemolytic 3% strep, 2% MRSA MRSA MSSA 59% MSSA 59% 17% 16% 2004 2008 Moran NEJM 2006; Talan CID 2011 Purulent Cellulitis • Cellulitis associated with purulent drainage or exudate without a drainable abscess – Empiric Rx for CA ‐ MRSA is recommended (AII). – Empiric Rx for  ‐ hemolytic strep unlikely needed (AII). – Duration of therapy: 5 ‐ 10 days, individualize based on clinical response Liu CID 2011; 52: 285 ‐ 322 4

5/28/2013 Outpatient purulent cellulitis: Empiric Rx for CA ‐ MRSA  ‐ hemolytic MRSA MSSA Comments strep TMP/ SMX + + ‐ Low rates of 1 ‐ 2 DS tab BID resistance Doxycycline, + + ‐ Low rates of Minocycline resistance 100 mg BID  C. diff risk Clindamycin +/ ‐ + + (  resistance) 300 ‐ 450 TID Linezolid + + + Most 600 mg BID expensive option Case 2 28 year old woman with erythema of her left foot x 48 hours. No purulent drainage, exudate or abscess. T 37.0 BP 132/70 P 78 Eells SJ et al Epidemiology and Infection 2010 5

5/28/2013 What is the appropriate management of this patient? A. Clindamycin 300 mg PO tid B. Cephalexin 500 mg QID C. Cephalexin 500 mg QID and TMP/ SMX 2 DS tab PO bid Nonpurulent Cellulitis:  ‐ hemolytic strep vs. staph? • Empiric Rx for  ‐ hemolytic strep recommended (AII) • Prospective study 1 , 248 hospitalized pts – 73% due to  ‐ hemolytic strep – 27% with no identified cause. – Overall 96% response rate to  ‐ lactam antibiotic (cefazolin, oxacillin, cephalexin, dicloxacillin). • Retrospective study 2 –  treatment failures with TMP ‐ SMX vs.  ‐ lactam or clindamycin * Consider coverage for MRSA if: History/evidence of MRSA infection elsewhere, failure to respond to  ‐ lactam 1 Jeng et al Medicine 2010; 2 Elliott et al Pediatrics 2009; Liu CID 2011; 52: 285 ‐ 322 6

5/28/2013 Cephalexin vs. Cephalexin + TMP ‐ SMX in patients with Uncomplicated Cellulitis N=146 Pallin CID 2013; 56: 1754 ‐ 1762 Outpatient nonpurulent cellulitis: Empiric Rx for  ‐ hemolytic streptococci, +/ ‐ MRSA  ‐ hemolytic strep MRSA MSSA Penicillin V ‐ K ‐ Rare +/ ‐ ‐ ‐ + 500 mg QID/ Amoxicillin 500 mg TID Dicloxacillin ‐ + + 500 mg QID Cephalexin ‐ + + 500 mg QID Clindamycin +/ ‐ + + (  resistance) 300 ‐ 450 mg TID Linezolid + + + 600 mg BID 7

5/28/2013 Microbiology of SSTI: Hospitalized Patients • 322 hospitalized patients with cellulitis, abscess, complicated SSTI • 97% of cases had S. aureus or Streptococcus spp. Enterococci 3% • 74% S. aureus or Streptococcus ONLY Jenkins CID 2010; 51: 895 ‐ 903 Antibiotic Utilization Following Implementation of a QI Project on Management of Inpatient SSTI *Recommended empiric vanco * *Discouraged gram neg/ anaerobic *Suggested Rx for 7 days * * *p<.05 * Jenkins Arch Intern Med 2011; 171: 1072 ‐ 9 8

5/28/2013 Other Outcomes •  Median duration of Rx (13 vs. 10d, p<.001) • No differences in clinical outcomes – Clinical failure (7.7% vs. 7.4%, p=NS) – Recurrent infection – Rehospitalization due to SSTI – Length of hospital stay Jenkins Arch Intern Med 2011; 171: 1072 ‐ 9 Complicated SSTI  Surgical debridement & empiric Rx for MRSA pending cx Antibiotic Adult Vancomycin 15 ‐ 20 mg/kg IV Q8 ‐ 12 Linezolid 600 mg PO/ IV BID Daptomycin 4 mg/kg IV QD Telavancin 10 mg/kg IV QD Ceftaroline 600 mg IV Q12 Tigecycline 100 mg IV x 1, then 50 IV Q12 9

5/28/2013 Summary: empiric management of SSTIs Non ‐ purulent Purulent ( β‐ hemolytic strep) (MRSA) • Cephalexin 500 QID • I&D • Dicloxacillin 500 QID Uncomplicated Consider addition of anti ‐ MRSA Consider MRSA active agent in antibiotic in select situations 1 select situations 2 • I&D plus vancomycin (or • Vancomycin (or Complicated alternative),no gram neg alternative), no gram neg in most cases 3 in most cases 3 1. Systemic illness, purulent cellulitis/wound infection, comorbidities, extremes of age, abscess difficult to drain or face/hand, septic phlebitis, lack of response of to I&D alone. PO antibiotic : TMP ‐ SMX 1 ‐ 2 DS BID, Clindamycin 300 mg TID, Doxycycline 100 PO BID 2. History/ evidence of MRSA elsewhere, failure to respond to  ‐ lactams 3. Except: critically ill pts with serious SSTI (nec fasc), perirectal/ periorbital infections, decubitus ulcer infections, severe diabetic foot infections, animal bites, water ‐ exposure Recurrent SSTI • Recurrent abscess, furunculosis: Staphylococcus aureus (MRSA and MSSA) • Recurrent cellulitis:  ‐ hemolytic streptococci 10

5/28/2013 Recurrent Staphylococcal SSTI Decolonization strategies: do they work? • Mupirocin ‐ based regimens appear to be effective in reducing S. aureus colonization • BUT no data shows decolonization prevents recurrent SSTI • Hygiene education: keep draining wounds covered, wash hands after touching infected wound, avoid sharing personal items, clean high touch surfaces • Regimens to consider: – Mupirocin +/ ‐ chlorhexidine or bleach x 5 ‐ 10 days – Dilute bleach baths: ¼ cup per ¼ tub (13 gallons) of water for 15 min, 2x/week for 3 mths Liu CID 2011; 52: 285-322; Fritz ICHE 2011; 32:872-80 Household vs. Individual Decolonization? • Open ‐ label RCT children with community ‐ onset SSTI and S. aureus colonization (nares, axilla, inguinal) 2 – Index case vs. household decolonization (mupirocin + CHG baths x 5d) – All received hygiene education: • Avoid sharing personal hygiene items • Use liquid pump or pour soaps and lotions (vs. bar soaps and lotion jars) • Launder towels and washcloths after each use • Launder bed linens once weekly – No difference in rate of eradication of S. aureus carriage. • @ 1 month: 50% vs. 51% (p = 1.0) • @ 12 months: 54% vs. 66% (p= .28) Fritz CID 2012; 54:743 ‐ 51 11

5/28/2013 Recurrent SSTI among Cases and Household Contacts p=.02 p=.008 p=.02 p=.12 Fritz CID 2012; 54: 743-51 Recurrent Cellulitis Is there a role for antibiotic prophylaxis? • Most patients have predisposing factor: – Obesity, lymphedema, venous insufficiency, prior trauma/ surgery to area, tinea pedis • Management approach: – Treat underlying conditions whenever possible (e.g. compressive stockings, Rx interdigital maceration/ tinea, emollients to avoid dryness/ cracking, diuretics) – Prophylactic antibiotics if frequent recurrence • Penicillin VK 250 mg PO twice daily • Benzathine PCN 1.2 MU IM monthly Stevens CID 2005 12

5/28/2013 PCN for Prevention of Recurrent Cellulitis • Multicenter, double ‐ blind RCT 274 pts with recurrent cellulitis – Penicillin 250 mg BID vs. placebo x 12 mths • Patient characteristics: – Chronic edema (66%), venous stasis (25%), tinea pedis (36%) • Outcomes: – Recurrent cellulitis: 22% (PCN) vs. 37% (placebo), p=.01 – After treatment stopped, no difference Thomas NEJM 2013; 368: 1695 ‐ 703 Case 3 • 21 yo M is tossing a ball in Golden Gate Park with a friend. As he goes after the ball, he passes close to a dog that was resting in the shade with his owner. The dog jumps up and bites him on the leg inflicting several puncture wounds on the calf. 13

5/28/2013 In addition to wound care, what is the appropriate management of this patient? A. No antibiotic prophylaxis is necessary B. Antibiotic prophylaxis with clindamycin C. Antibiotic prophylaxis with amoxicillin/ clavulanate D. Administer rabies immunoglobulin and rabies vaccine for post ‐ exposure prophylaxis E. C and D Microbiology of Animal Bites: What’s in their mouth and on your skin • Average 5 organisms (range 0 ‐ 16) per wound Dogs Cats Pasturella sp 50% 75% Streptococcus sp. 46% 46% Staphylococcus aureus 20% 4% Anaerobes mixed w/ aerobes 48% 63% Anaerobes alone 1% 0% Talan NEJM 1999 14