Bugs and Drugs 2011


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Warren Joseph lecture at DFCON 2011 in Hollywood, CA back in late March. The topic is "Bugs and Drugs 2011". As sometimes happens at that excellent meeting, I did not have enough time to go through the entire talk so, even back then, I offered to put the lecture up on my blog for viewing. I hope you find the information on the slides interesting and informative. If you have any questions about any content or see a subject on which you would like me to expound on this site, please let me know.

As always, comments on the site are welcomed.

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  • Vancomycin MIC on the Move 1 A single-center retrospective analysis of susceptibility test results for 6003 S aureus isolates from 2000 to 2004. Vancomycin minimum inhibitory concentration (MIC) was determined by broth dilution as recommended by the Clinical and Laboratory Standards Institute. The percentage of MRSA isolates with MIC >1 was higher than the percentage of methicillin-susceptible S aureus (MSSA) isolates over the 5-year period (54.9% for MRSA vs 31% for MSSA). The prevalence of methicillin resistance in S aureus isolates increased from 24.9% in 2000 to 45.1% in 2004. Only one isolate, in 2001, was reported to be vancomycin-intermediate S aureus (MIC 8 µ g/mL); no vancomycin-resistant S aureus isolates were detected. Reference 1. Wang G, Hindler JF, Ward KW, Bruckner DA. Increased vancomycin MICs for Staphylococcus aureus clinical isolates from a university hospital during a 5-year period. J Clin Microbiol . 2006;44:3883-3886.
  • Bugs and Drugs 2011

    1. 1. Warren S. Joseph, DPM, FIDSA Roxborough Memorial Hospital, Phila., PA www.leinfections.com
    2. 8. <ul><li>Deep soft tissue & Bone cultures grew MSSA & Group B Streptococcus </li></ul><ul><li>Patient initially on Vanco + pip/tazo </li></ul><ul><li>Given these bugs…what drug do you choose? </li></ul><ul><li>Cephalexin </li></ul>
    3. 9. <ul><li>A marked decrease in patients presenting with MRSA </li></ul><ul><li>An increase in ESBL/KPC caused DFI </li></ul><ul><li>The approval and release of ceftaroline </li></ul><ul><li>The revised IDSA DFI Guidelines </li></ul>
    4. 10. <ul><li>“ Aerobic gram-positive cocci (especially Staphylococcus aureus) are the predominant pathogens in diabetic foot infections. Patients who have chronic wounds or who have recently received antibiotic therapy may also be infected with gram-negative rods, and those with ischemia or gangrene may have obligate anaerobes.” CID Oct 1, 2004 </li></ul>
    5. 11. <ul><li>May be true in mild infection but no definitive data </li></ul><ul><li>Polymicrobial flora may worsen prognosis </li></ul><ul><li>Caution in severe infection and in osteomyelitis </li></ul>Slide Courtesy of A. Berendt, MD Anti-Staph and Strep antibiotic Staphylococcus aureus Beta-haemolytic Strep Enterobacteriaceae Anaerobes Commensal gram-positive cocci
    6. 12. <ul><li>IDSA Mild (po) </li></ul><ul><li>ASOC </li></ul><ul><li>Amoxicillin/clavulanic acid </li></ul><ul><li>Clindamycin </li></ul><ul><li>Oral PRP </li></ul><ul><li>Moderate/Severe </li></ul><ul><li>Β -l actam/ β -l actamase inhibitor compound </li></ul><ul><li>Ertapenem </li></ul><ul><li>Cefazolin </li></ul><ul><li>Clindamycin (IV/PO) </li></ul><ul><li>Vancomycin </li></ul>
    7. 13. <ul><li>NEJM Jan 2009 </li></ul>THE ROLE OF HANDWASHING IN THE SPREAD of MRSA
    8. 14. <ul><li>Mild </li></ul><ul><li>Later generation tetracycline (PO) </li></ul><ul><ul><li>Minocycline </li></ul></ul><ul><ul><li>Doxycycline </li></ul></ul><ul><li>TMP/SMX </li></ul><ul><li>Clindamycin (+/-) </li></ul><ul><li>Moderate/Severe </li></ul><ul><li>Linezolid (IV/PO) </li></ul><ul><li>Vancomycin (IV) </li></ul><ul><li>Daptomycin (IV) </li></ul><ul><li>Tigecycline (IV) </li></ul><ul><li>Ceftaroline (IV) </li></ul>
    9. 15. <ul><li>An increasing clinical problem </li></ul><ul><li>“ Staph aureus with reduced susceptibility to vancomycin” </li></ul><ul><li>aka “MIC Creep” </li></ul><ul><ul><li>Difficult to detect </li></ul></ul><ul><ul><li>MIC on the rise from 0.5 » 1.0 » 2.0 µg </li></ul></ul><ul><ul><li>Have been associated with Tx failures </li></ul></ul><ul><li>PLEASE – Look at your vancomycin MIC if considering its use against MRSA! </li></ul>
    10. 16. Wang G et al. J Clin Microbiol . 2006;44:3883-3886. % of Isolates 79.9 19.9 0.2 0.2 0.3 0.2 0.8 80.9 18.9 64.6 35.1 60.1 39.7 70.4 28.8 MIC=minimum inhibitory concentration.
    11. 18. <ul><li>“ If you show a vancomycin MIC against MRSA of >1µg/ml you can not achieve a level of vancomycin that is high enough to be both safe and effective. You should use an alternative agent” </li></ul><ul><li>paraphrasing Robert Moellering, MD, ICAAC 2009 </li></ul>
    12. 19. Courtesy of Lee Rogers, DPM
    13. 20. <ul><li>This one is easy…pretty much anything you use for Staphylococcus will be active against Group B Streptococcus </li></ul>
    14. 21. <ul><li>Extended Spectrum β -lactamases (ESBL) </li></ul><ul><ul><li>Increasing in E. coli , Proteus mirablis & Kleb pneumo along with other gnr </li></ul></ul><ul><ul><li>Resistant to most penicillins, cephalosporins and β lactamase inhibitor compounds </li></ul></ul><ul><ul><li>Still susceptible to most carbapenems and tigecycline </li></ul></ul><ul><li>Carbapenemase producing gnr (KPC) </li></ul><ul><ul><li>Not yet as common as ESBL </li></ul></ul><ul><ul><li>As name implies, resistant to carbapenems </li></ul></ul><ul><li>NDM-1 </li></ul><ul><li>Do we need to concern ourselves?? </li></ul>
    15. 22. <ul><li>Do we really need to treat it? </li></ul><ul><li>Options </li></ul><ul><li>Ciprofloxacin (PO/IV) </li></ul><ul><li>Ceftazidime (IV) </li></ul><ul><li>Cefepime (IV) </li></ul><ul><li>Aztreonam (IV) </li></ul><ul><ul><li>+/- Aminoglycoside </li></ul></ul><ul><li>Other quinolone </li></ul><ul><li>Piperacillin/tazobactam * </li></ul>
    16. 24. <ul><li>“ Head of the Snake” principle </li></ul><ul><li>Consider empiric “De-escalation” therapy depending on local MRSA prevalence </li></ul><ul><li>Watch your vancomycin MICs for “creep” </li></ul><ul><li>Be aware of ESBLs and KPCs in your hospital (speak with your IC specialist) </li></ul><ul><li>Be alert for “Pseudomonophobia” </li></ul>