1. Dr. giridhar boyapati

2. Classification of staph. aureus1. M.S.S.A2. B.R.S.A3. M.R.S.A4. G.I.S.A 3. METHICILLIN Narrow spectrum beta-lactumantibiotic Semi synthetic penicillin Only i.v use Resistant to hydrolysis by beta lactamases Adverse effects :interstitial nephritis No longer in clinical use. 4. Methicillin resistancemec A gene Acquired probably from coagulase negativestaphylococci S.A : penicilins > PBP-2 on cell wall MRSA : mec A gene encodes for PBP-2A which isresistant to binding by penicillins 5. Methicillin resistance MRSA resistant to1. penicillins2. cephalosporins except ceftaroline3. carbapenams4. Flouroquilonolones5. macrolides ( erythro, clarythro, azithro) 6. Types of MRSA 1. COMMUNITY-ACQUIRED MRSA 2. HOSPITAL-ACQUIRED MRSA 7. HA -MRSA Health care exposure required ( extensive antibiotictherapy, admission in icu, endo-trachealtube,centralvenous catheter, long duration hospital stay.) Presentation : bacteremia,pneumonia Toxin production: rare Highly drug resistant 8. CA -MRSA No health care exposure Presentation : asymptomatic colonization, SSTI,bacteremia,pneumonia Toxin production is common Less drug resistant 9. .TreatmentProtocol 10. DRUGS 1. CLINDAMYCIN 2. TETRACYCLINES : DOXYCYCLINE/MINOCYCLINE 3. TMP/SMX 4. RIFAMPICIN 5. LINEZOLID 6. VANCOMYCIN 7. Daptomycin 8. Ceftaroline 11. Assymptomatic nasal colonization 29% of individuals have MSSA 1.5% have MRSA NO active treatment required 12. UNCOMPLICATED ABSCESS Incision & Drainage alone Antibiotic therapy not required Wound is left open 13. Complicated abscess Severe or extensive disease Systemic illness Associated comorbidities or immunosuppression Extremes of age Difficulty to drain the abscess Septic phlebitis Antibiotics for 5 to 10 days 14. Recurrent MRSA infections Environmental & personal hygiene Decolonization strategies1. nasal decolonization: topical mupirocin2. topical body decolonization : 4%chlorhexidine,dilute bleech baths3. oral antibiotis not routinely recommended. 15. Uncomplicated bacteremia Antibiotics for 2 weeks MIC testing for vancomycin and at least 1alternativeagent 16. Complicated bacteremia Positive echocardiogram (IE) Indwelling prosthetic material (valves,shunts) Positive blood culture even 4 days of antibiotic therapy Evidence of metastatic foci Antibiotics for 4 -6 weeks 17. Bacteriuria 24-34% of patients with bacteremia also developbacteriuria. Bacteremia+Bacteriuria = high mortality 18. MRSA Pneumonia High mortality Treated withlinozolidvancomycinDaptomycin is contraindicatedAntibiotics for 7- 21 days 19. MRSA EndocarditisIntravenous vancomycin or daptomycin (6 mg/kg iv)for 6 weeks is recommended.Some experts recommend higher dosages ofdaptomycin (8 to 10 mg/kg iv ).Adding gentamicin or rifampin to vancomycin is notrecommended in patients with bacteremia or nativevalve infective endocarditis. 20. Patients with infective endocarditis and a prostheticvalve should be treated with:Intravenous vancomycin + rifampicin+ gentamicinfor a minimum of 6 weeks. Early evaluation for valve replacement surgery isrecommended. 21. MRSA MENINGITIS Intravenous vancomycin for 2 weeks. Some experts recommend adding rifampin BRAIN ABSCESS, SUBDURAL EMPYEMA, ANDSPINAL EPIDURAL ABSCESS Neurosurgical evaluation for incision and drainage isrecommended Intravenous vancomycin for 4-6 weeks 22. MRSA infection inOrthopaedicsurgery 23. .Nearly half of the entire surgical site infections arecaused by staphylococci.Of these 81% are Staph. aureus, and 63% areresistant to methicillin.The rate of methicillin resistance is higher inorthopaedic units compared to other medicalspecialities.MRSA produces biofilm and becomes moreresistant to antibiotics. 24. MRSA infections Superficialsurface exudatessurface woundDeepBacteraemiaJoint AspirateBone/Soft Tissue specimens/ Surgical ImplantDeep wound/intra-operative swabs 25. Prevalence of MRSA to be1.6% within an orthopaedicdepartment0.3% within the generalhospital settingThe SENTRY study showed that althoughthe overall numbers of staphylococcalinfections within an orthopaedic settingwere low in comparison with those in 26. IDSA guidelines fortreatment ofMRSA infections 27. MRSA osteomylitis Surgical debridement and drainage of associated soft tissueabscesses. Administration of antibiotic: Parenteral, oral, or initialparenteral therapy followed by oral therapy may be used Antibiotics available for parenteral administration includeIV vancomycin and daptomycin 6 mg/kg/dose IV Oral : TMP-SMX 4 mg/kg/dose BD + rifampin 600 mg ODlinezolid 600 mg twice daily,clindamycin 600 mg every 8 h . 28. Some experts recommend the addition of rifampin600 mg daily or 300450 mg twice daily to theantibiotic chosen above.For patients with concurrent bacteremia , rifampinshould be added after clearance of bacteremia. The optimal duration of therapy for MRSAosteomyelitis is A minimum 8-week course isrecommended Additional 13 months ( for chronic infection or ifdebridement is not performed) of oral rifampin-basedcombination therapy with TMP-SMX,doxycycline, minocycline, clindamycin, or afluoroquinolone. 29. o MRI with gadolinium is the imaging modalityof choice, particularly for detection of earlyosteomyelitis and associated soft-tissuedisease . ESR and/or CRP level may be helpful to guideresponse to therapy 30. SEPTIC ARTHRITIS Arthrotomy and drainage 3-4 week course therapy recommended 31. Implant related infections Early-onset (less than 2months after surgery) Acute hematogenous prosthetic joint infectionsinvolving a stable implant Short duration of symptoms (three weeks or less) Debridement (but device retention),Parenteral therapy + rifampin , followed by rifampinplus a fluoroquinolone, TMP/SMX, a tetracycline, orclindamycin for 3 months for hips and 6 months forknees. 32. Late (> 2 mos postop): Implant is unstable, later onset infection or > 3wks symptoms Remove hardware and administer antibiotics . 33. Spinal implant related infections Early onset spinal implant infections (30 days or lessafter surgery) Implants in an actively infected site,Parenteral therapy plus rifampin followed byprolonged oral therapy is recommended.The optimal duration of parenteral and oraltherapy is unclear;Oral therapy should be continued until spinalfusion has occurred. 34. For late-onset infections (more than 30 days aftersurgery), device removal is recommended. Long-term oral suppressive antibiotics (e.g.,TMP/SMX, a tetracycline, a fluoroquinolone inconjunction with rifampin, clindamycin ) with orwithout rifampin may be considered, particularly ifdevice removal is not possible 35. MRSA IN CHILDREN Vancomycin is recommended in children with acutehematogenous MRSA osteomyelitis and septicarthritis. If the patient is stable without ongoing bacteremia orintravascular infection, clindamycin can be used. The duration of therapy should be individualized, buta minimum of3-4 weeks is for septic arthritis4-6 weeks for osteomyelitis. Daptomycin and linezolid are alternative therapies