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Microbial Colonization and New Resistant Organisms Bryan Larsen, PhD Marian University College of Osteopathic Medicine.

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Presentation on theme: "Microbial Colonization and New Resistant Organisms Bryan Larsen, PhD Marian University College of Osteopathic Medicine."— Presentation transcript:

1 Microbial Colonization and New Resistant Organisms Bryan Larsen, PhD Marian University College of Osteopathic Medicine

2 Perspective: Penicillin – “the first shall be last” Colonization: Contemporary concepts Where it all begins, Where it stops Cataloging the organisms of concern Conceptualizing and Implementing Antibiotic Stewardship The Pipeline is not the answer

3 Ernst Chain D 1979 Howard Florey D 1968 Norman Heatley D 2004 Alexander Fleming D 1955

4 I wonder who took the wonder out of wonder drugs? WWII began before we had penicillin The need was compelling Staph, strep, burn wound infection in Battle of Britain had no real antibiotic Clinical tests were based on the availability of very few available doses Clinical results were spectacular Penicillin was deemed to be a “wonder drug” WWII began before we had penicillin The need was compelling Staph, strep, burn wound infection in Battle of Britain had no real antibiotic Clinical tests were based on the availability of very few available doses Clinical results were spectacular Penicillin was deemed to be a “wonder drug”

5 I wonder who took the wonder out of wonder drugs? Penicillin was so scarce and precious and effective in the early days, that urine was collected and processed to recover excreted drug Mid 1942 there was enough to treat 10 patients Chain, Florey, Heatley developed scale up in 1942 Peoria was the location of massive fermentation of Penicillin in Corn-steep liquid billion units produced (100K units/dose) Penicillin was so scarce and precious and effective in the early days, that urine was collected and processed to recover excreted drug Mid 1942 there was enough to treat 10 patients Chain, Florey, Heatley developed scale up in 1942 Peoria was the location of massive fermentation of Penicillin in Corn-steep liquid billion units produced (100K units/dose)

6 “Familiarity breeds contempt” While many drugs treated illness, few could effect a complete “cure” Antibiotic therapy became commonplace The success of antibiotics led to eagerness to use for expanding indications (even when evidence was anecdotal) By the 1950’s there were other wonder drugs While many drugs treated illness, few could effect a complete “cure” Antibiotic therapy became commonplace The success of antibiotics led to eagerness to use for expanding indications (even when evidence was anecdotal) By the 1950’s there were other wonder drugs

7 Victims of their own success… Today there are hundreds of anti-infective compounds listed in the PDR Experts have opined that 50% of antibiotic use is either inappropriate or ineffective We will take up this controversial concept at the close of this talk

8 Victims of microbial success… When previously susceptible microorganisms develop the ability to resist the action of an antimicrobial drug, use of that drug becomes ineffective Development of resistance is driven (largely) by microbial exposure to antibiotics through selective pressure Eliminate antibiotic, antibiotic and you eliminate selective pressure for resistance

9 Penicillin was so scarce and precious in the early days, that urine was processed to recover excreted drug Perspective: Penicillin – “the first shall be last” Colonization: Contemporary concepts Where it all begins, Where it stops Cataloging the organisms of concern Conceptualizing and Implementing Antibiotic Stewardship The Pipeline is not the answer

10 Colonization (Classical) Direct infection with a drug resistant is possible; colonization prior to disease is typical Humans have an abundant indigenous flora at all sites accessible to the environment Microbial cells outnumber human cells Microbial cells can be shed and survive; human cells cannot The microbial flora is polymicrobial and stable

11 Colonization (Contemporary) Its not them versus us (the flora is an organ of the human body) Until deep-sequencing and metagenomics the full diversity of the flora was not appreciated Microbial ecology indicates there are functional roles for organisms that are independent of species One functional microbial class may be the master regulator of the normal flora Strain replacement may occur Community types may vary over time but the mechanism is unknown

12 Diversity, Regulation, Stability R. Hummelen et al PLOS1 November 2011 doi:info:doi/ /journal.pone g002

13 Acquisition of Antimicrobial Resistant Organisms Confined Community Compromised Changing geography In hospital – Organisms exposed to antibiotics – Patients exposed to sources of organisms Intensive care Long term care Rehabilitation center

14 Simultaneous Occurrences Antibiotics used for therapy and present in the hospital environment put selective pressure on host microflora to increase prevalence of resistant strains Resistant community bacteria present in patients, staff and visitors enter the hospital environment Hospital activities move resistant strains from person to per person with potential for colonization

15 Long term care Prospective enrollment with periodic multi- site culture 47% entered the LTC facility with CIP-R Time to acquisition (among non-colonized): – CIP-R75.5 days – MRSA126.6 days – CAZ-R176 days – VRE186 days J Fisch et al. J Clinical Micro February 2012

16 Incidence of acquisition of ARO (MRSA, VRE, CR-PA) per 1000 days of antibiotic treatment Tancrelli, et al. Antimicrob Agents Chemother 2009; 53: 4264

17 Acquisition of Antimicrobial Resistant Organisms Confined Patients Community Populations Compromised Persons Changing geography Drug resistant Pneumococcus ESBLs with cephalosporin UTI prophylaxis MRSA skin infections MDR TB Resistant STDs

18 Enterococcus in Surface Waters Des Moines River Watershed 6408 Square Miles 14 towns of > 5000 Row Crops and CAFO Site 40 is Des Moines, Iowa

19 The Associated Press April 11, 2012, 5:25PM FDA wants limits on antibiotics given to animals By MATTHEW PERRONE WASHINGTON The Food and Drug Administration called on drug companies Wednesday to help limit the use of antibiotics in farm animals, a decades-old practice that scientists say has contributed to a surge in dangerous, drug-resistant bacteria…. …The FDA has struggled for decades with how to tackle the problem because the powerful agriculture industry argues the drugs are a key part of modern meat production…. …Under the new FDA guidelines, the agency recommends antibiotics be used "judiciously," or only when necessary to keep animals healthy. The agency also wants to require a veterinarian to prescribe the drugs. They can currently be purchased over-the-counter by farmers…. The draft recommendations by the FDA are not binding, …

20 Acquisition of Antimicrobial Resistant Organisms Confined Patients Community Populations Compromised Persons Changing geography Prior antibiotic therapy Immune compromise Constitutional compromise, hydration, trauma, surgery Cancer Diabetes Etc

21 Incidence of ARO acquisition after Abx Tx was higher in compromised pts than among overall pt population Relevant groups were: – Dialysis – DM – ICU – Cirrhosis – Renal failure – Cancer – Age > 70 – HIV Tancrelli, et al. Antimicrob Agents Chemother 2009; 53: 4264

22 Population Movement Population movement has the potential of carrying resistant microorganisms to new places and new peoples Non colonized persons may go to locations where resistant organisms are prevalent Millions (year) Refugees16(‘07) Asylum Seekers0.65(‘07) Displaced 51(’07) Travel924(‘08) Seasonal Migr.2.4(‘05) Int’l. Students2.1(‘03) Migrant Work86(‘05) Trafficked0.8 Domestic Air Arr. 900(‘07) MacPherson et al, Emerging Infectious Disease 2009; 15:1727

23 Perspective: Penicillin – “the first shall be last” Colonization: Contemporary concepts Where it all begins, Where it stops Cataloging the organisms of concern Conceptualizing and Implementing Antibiotic Stewardship The Pipeline is not the answer

24 Brief summary of concerning organisms Organisms intrinsically resistant One of the significant goals is reduction of CDAD in hospitals and long term care Organisms with acquired and / or transferrable resistance Multidrug resistant organisms

25 Concerning Organisms MRSA- methicillin/oxacillin-resistant Staphylococcus aureus MRSA VRE - vanomycin-resistant enterococci ESBLs - extended-spectrum beta lactamases (resistant to cephalosporins and monobactams) PRSP - penicillin-resistant Streptococcus pneumoniae GISA - glycopeptide-intermediate Staphylococcus aureus VISA - vancomycin-intermediate Staphylococcus aureus VSRA - vancomycin-resistant Staphylococcus aureus (not yet found in nature, but it is believed it will emerge or evolve from VISA), and MDR-TB - multidrug-resistant tuberculosis.

26 Perspective: Penicillin – “the first shall be last” Colonization: Contemporary concepts Where it all begins, Where it stops Cataloging the organisms of concern Conceptualizing and Implementing Antibiotic Stewardship The Pipeline is not the answer

27 Antibiotic Resistance? Just develop new products!

28 This figure from a “Commentary” by Cooper and Shales, Nature 472:32, 2011

29 What is the pipeline? Drug Discovery Preclinical (in vitro and in vivo investigation) Phase 0 Clinical (IND enabling research) Phase 1 Safety, Dose Ranging Phase 2 Safety, Efficacy, PK, PD Phase 3 Clinical Efficacy, Safety – per indication NDA Marketing and Phase 4 monitoring

30 Fix the antibiotics pipeline… “Only 4 new classes of antibiotics have been launched in the past 40 years” “Phase III clinical trials for a single disease indication cost about $70 million” Investment capital is not attracted to drugs that are used mainly for short courses The possibility of resistance development means that new antibiotics may be short-lived anyway MA Cooper and D Shales, Nature 34, April 7, 2011

31 Perspective: Penicillin – “the first shall be last” Colonization: Contemporary concepts Where it all begins, Where it stops Cataloging the organisms of concern Conceptualizing and Implementing Antibiotic Stewardship The Pipeline is not the answer

32 Concept Antimicrobial resistance is driven by drug use Therefore less drug use will result in less resistance Antibiotics are powerful resources so wholesale abandonment is not an option Since 50% of use is considered ineffective or irrational, antibiotic stewardship is a program for appropriate use across institutions and specialties

33 Individual approach to antibiotic stewardship Logical, evidence based, as specific as possible with attention to local resistance issues, and collaboration of the patient When ordering: include indication, dose, discontinuation When patients are transferred antibiotic treatments may be continued unnecessarily

34 12 Step Program for Institutional Stewardship of Antibiotic Use Prevent Infections 1.Vaccination – even antiviral vaccination can lessen the tendency to antibiotic use 2.Get the catheters out

35 12 Step Program for Institutional Stewardship of Antibiotic Use Diagnose and Treat Effectively 3.Use appropriate methods for diagnosis 4.Target the pathogen

36 12 Step Program for Institutional Stewardship of Antibiotic Use Use Antimicrobials Wisely 5.Access the experts 6.Practice antimicrobial control 7.Use local data 8.Treat infection and not colonization 9.Know when to say “no” 10.Stop treatment

37 12 Step Program for Institutional Stewardship of Antibiotic Use Prevent Transmission 11.Practice Infection Control 12.Practice Hand Hygiene


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