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1 Gram negatives: Mechanisms of Resistance & Lab detection Johann DD Pitout MD, FF Path (SA) University of Calgary Calgary Laboratory Services Calgary, Canada johann.pitout@cls.ab.ca
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22 Transparency declaration Research grants from Merck Frosst, Wyeth and Astra Zeneca Speaker for Merck Frosst
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33 Overview Introduction Clones, stones and bones… Newer ß-lactamases Laboratory detection Emergence of clones in Enterobacteriaceae Summary
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Am J Med 2006;119(sup1):S62-70 Why Enterobacteriaceae? NB causes of serious bacterial infections: Community Hospital Several species: E. coli (ExPEC) K. pneumoniae Salmonella spp Surveillance: Top 5 community and hospital pathogens
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Trends Microbiol 2006;14:413-20 Why Resistance? Resistance is concern: 3 rd GenCephs Carbapenems Fluoroquinolones Empiric treatment complicates antibiotic selection Inadequate initial Rx (AAC 07;51:1987) risk for mortality health-care costs (AAC 06;50:1257
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CMI 2007;13:1-46 What is a clone? Definitions: Isolate, strain, clone Clone: Isolates with identical phenotypic+genotypic characteristics Different sources/time Typing methods: MLST PFGE PCR fingerprint (MLVA)
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clonalclonal
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AnnRevMicro 2006;60:561-88 MLST Sequence variation Housekeeping genes Evolutionary relationship Comparing isolates NOT outbreaks ST’s and CC’s E-BURST NOgapAinfBmdhpgiphoErpoBtonBST Kp CG 33111118340 Kp ON 34617438147 Kp SA 23111148569
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CID 2007;44:418-23 PFGE Restriction of genomic DNA Rare-cutting enzyme +++ discrimination Excellent outbreaks Various species But not portable: Labour intensive ? Reproducible Time consuming
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ST
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1212 Newer ß-lactamases EnzymesInhibitedSpectrumOrganismsExamples ESBLsClavulanateCephalosporinsPenicillins Klebsiella spp. E. coli TEM, SHV, CTX-M Plasmid-AmpCsCloxacillin Boronic acid Cephalosporins Cephamycins Klebsiella spp. E. coli Salmonella spp. CMY, FOX MBLs(CHE-B)EDTACarbapenemsCephalosporins P. aeruginosa Klebsiella spp E. coli IMP, VIM, NDM KPC’s(CHE-A)Clavulanate Boronic acid CarbapenemsCephalosporins Klebsiella spp. E. coli KPC
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13 Clinical Case no 1 3 month girl with diarrhoea Watery with mucus Abnormal growth parameters Admitted and Rx Previous diarrhoea Other family members Older sister and Dad Salmonella enterica serotype Newport
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14 Salmonella spp. Susceptibility CFZ >64 TZP >64/4 CAZ 16 CRO 16 FOX >64 FEP <16 ATM 16 CIP <0.25 GEN <8 IPM <2 CLSI ESBL confirmation test: CAZ 12mm CAZ + CLAV 15mm CTX 16mm CTX + CLAV 16mm Neg ESBL test
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15 CTT +PBA
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16 ClinMicroRev 09;22:161-82 AmpC ß-lactamases Chromosomal Organisms: Enterobacter, Serratia, Citrobacter, Pseudo. cephalosporinases inducible not inhibited by c,t,s eg.: AmpC Plasmid Organisms: Klebsiella, P. mirabilis, Salmonella spp. cephalosporinases constitutive/inducible not inhibited by c,t,s eg.: CMY, FOX, DHA, ACC
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1717 DMID 01;41:57-61 E. coli and AmpC’s Weak promoter Strong attenuator Plasmid-mediated AmpC mutations
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1818 ClinMicroRev 09;22:161-82 Plasmid-mediated AmpC’s R to cephamycins some cephalosporins, penicillins Not carbapenems Multiresistant Organisms: K. pneumoniae, E. coli, Salmonella spp Origin Extended-spectrum cephs
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19 ERAIT 08;6:657-69 Laboratory detection No guidelines Not all cephamycin/3 rd GC R = AmpC Phenotypic tests Inhibitor-based approaches Disks: boronic acid and others AmpC E-test: cloxacillin Multiplex PCR
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22 Clinical case no 2 47 yr F with recent travel ER with fever, dysuria, frequency Exam: T 39.2ºC supra-pubic and renal tenderness Diagnosis of UTI 2 sets of BC, urine Rx ciprofloxacin, referred to HPTP Next day blood cultures positive
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23 Escherichia coli Susceptibility CFZ >64 TZP 64/4 CAZ 16 CRO >32 FOX <8 FEP 16 ATM 16 CIP >4 GEN >16 IPM <2 CLSI ESBL confirmation test: CAZ 22mm CAZ + CLAV 23mm CTX 8mm CTX + CLAV 20mm Pos ESBL test
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24 AmJMed 97;103:51-9 Extended-spectrum ß-lactamases Early 1980’s World-wide Hydrolyse: cephalosporins, penicillins, monobact not: cephamycins, carbapenems Inhibitor sensitive clav, sulb, tazo Types Enterobacteriaceae Clinically relevant
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CLSI guidelines 2010 MIC ≥ 1 CTX/CRO ≥ 2 CAZ Zone ≤ 26mm CTX, ≤ 23mm CRO, ≤ 21mm CAZ No confirmatory test for therapy but useful for infection control/epidemiology
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26 Detection of ESBLs E. coli, Klebsiella spp, P.mirablis, Salmonella spp All other Enterobacteriaceace CLSI Screen positive CRO: 1ug/ml and CAZ: 1ug/ml Modified double disk FEP + CLAV CLSI ESBL disk confirmation test: CTX and CTX with Clav CAZ and CAZ with Clav CLSI Screen positive CRO: 1ug/ml and CAZ: 1ug/ml
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Clinical case no 3 32yr M travelled in Southern India Admitted city Mysore: Hyperglycemia Developed upper UTI Rx with Ciprofloxacin Transferred to Alberta Upper UTI and prostatitis Rx with ERT
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28 Escherichia coli (MH01) Suscept CFZ >64 TZP >64/4 CAZ >64 CRO >64 FOX >64 FEP >64 ATM >64 CIP >8 GEN >16 IPM 16 ESBL confirmation: CAZ 6mm CAZ + CLAV 6mm CTX 6mm CTX + CLAV 6mm AmpC boronic test: CTT 6mm CTT + PBA 6mm ERT 6mm
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ClinMicroRev 2005;18:306-25 Class B CHE’s Metallo-ß-lactamases (MBLs) Active site: Zn+ Inhibited by EDTA R to all ß-lactams except: monobactams Chromosomal (Steno) Types: IMP, VIM, SPM, GIM, SIM, AIM, KHM, DIM, NDM
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JAC 2011;66:689-92 NDM ß-lactamases 1 st report from Sweden (AAC 2009;53:5046-54) Worldwide Widespread in Subcontinent (Lancet ID 2010 10;597-602) India, Pakistan, Bangladesh Associated with travel (medical tourism) Organisms: E. coli (community) Klebsiella spp. (hospital) MultiR ? Fatal cases
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32 Clinical case no 4 CAP external quality assurance program Klebsiella pneumoniae Urine; significant colony count Adult Diabetic patient Neurogenic bladder ICU for 2 weeks Recently hospitalised in New York
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33 Klebsiella pneumoniae Susceptibility CFZ >64 TZP >64/4 CAZ >64 CRO >64 FOX >64 FEP 16 ATM >64 CIP >8 GEN >16 IPM 2 ESBL confirmation: CAZ 10mm CAZ + CLAV 13mm CTX 11mm CTX + CLAV 14mm AmpC boronic test: CTT 10mm CTT + PBA 22mm ERT 6mm
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35 Class A CHEs Different types (e.g.SME) KPC ß-lactamases K. pneumoniae Carbapenemase 1 st reported late 1990’s North Carolina Hydrolyze all ß-lactams Including carbapenems Inhibited by clavulanate Types: KPC 2-??? Klebsiella Producing Chaos Lancet Infect Dis 2009;9:228-36
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CLSI June 2010 Carbapenemases & Enterobacteriaceae MIC ≥ 0.25 ERT, ≥ 1 IPM/MER/DOR Zone ≤ 22 mm ERT/IPM/MER/DOR No confirmatory test for therapy if I or R to all carbapenems tested but OK for infection control/epidemiology
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++false positives with ERT Use MER Multiplex PCR >0.25
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Multiplex PCR
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EuroSurveill 2010;15:pii
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4040 Curr Opin Microbiol 2006;9:466-75 CTX-M ß-lactamases Active CeftoTaXime 1 st Munich activity CTX by tazobactam 40% similarity to SHV/TEM Originate from Kluyvera spp. Insertion element: ISEcp1 Divided into 5 groups Groups 1, 2, 8, 9, 25
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41 CTX-M-type ESBLs: first reports 1989 Matsumoto et al. AAC 1988; 32:1243 Bauernfeind et al. Infection 1990; 18:294 Power et al. AAC 2002; 46:602 1986 1990s
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42 Lancet Infec Dis 08;8:159-66 The CTX-M pandemic: since 2000
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43 Lancet Infec Dis 08;8:159-66 The CTX-M-15 pandemic: since 2003
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44 Dissemination of CTX-M-15 MLST profile ST131 Broadly disseminated Homogenous virulence genotype IncF group plasmids 3 different profiles OXA-1, aac(6)-Ib-cr, TEM-1 JAC 08;61:273-81, EID 08;14:195-200
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45 IJAA 10; 35:316-21 The clone ST131 pandemic: since 2006
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46 AAC 10;54:1327-30 MLST clone ST131 (96/209 [46%])
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4747 E. coli from blood
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48 Distribution of ST131 (69/134[51%]) AAC 09;53:2846-51
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49 Characteristics of ST131
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50 IJAA 10;35:316-21 ST131 CTX-M-15 What makes ST131 so special? Uropathogenic Phylo B2 Certain VF’s Adherence IncF plasmids R factors Addiction systems
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CTX-M ESBLs Kluyvera spp E. coli CTX-M-1 CTX-M-15 ST131 ISEcp1
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52 Significance of KPCs Multiple R (Rx options very limited) Nosocomial clonal outbreaks Inter-hospital, inter-city, inter-country Infections Systemic (invasive devices) UTIs (indwelling catheters) Not only in K. pneumoniae BSIs ↑ mortality (Infect Control Hosp Epidemiol. 2010 Oct 25) Lancet Infect Dis 2009;9:228-36
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53 ST258
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FEMSMicroReviews 2011 Feb 9 KPC and clones ST258 40% of KPC’s CTX-M-14 Hypervirulent clone Other STs ST438 (Brazil) Also: Mobile elements (Tn4401) Plasmids
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KPC’s Environmental bugK. pneumoniae KPC-2 Tn4401 KPC-2/3 ST258
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JAC 2011;66:689-92 Worldwide distribution of NDMs Cricket WC
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JAC 2011;66:689-92 NDMs and clones K. pneumoniae Not clonally related Broad-host range plasmids e.g. A/C, N E. coli Clonal ST101 (Canada, UK, Europe, Australia) ST131 USA (scary)
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What makes a clone…. International clones Virulence Adherence factors Plasmids Narrow host range Broad host range Clones use plasmids and plasmids use clones Plasmids as per BioShock: “giving the user what some might call super powers"
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59 MLST clone ST131 Understanding how ST131 has emerged and successfully disseminated within the hospital and community, including across national boundaries, should be a public health priority Neil Woodford, UK JAC 2008;61:233-4
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60 Acknowledgements University of Calgary: K. Laupland D. Church D. Gregson Calgary Lab Services: L. Campbell B. Chow G. Peirano NML: M. Mulvey D. Boyd Special Mention: L. Poirel, K. Thomson, N. Hanson, E. S-Molland, J. Johnson, D. Guttman
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