Multidrug-Resistant Organisms: Where Are We with Detection and Reporting in 2015?

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1 Analysis. Answers. Action. Multidrug-Resistant Organisms: Where Are We with Detection and Reporting in 2015? Audrey N. Schuetz, MD, MPH 1

2 Faculty Disclosure The Association of Public Health Laboratories adheres to established standards regarding industry support of continuing education for healthcare professionals. The following disclosures of personal financial relationships with commercial interests within the last 12 months as relative to this presentation have been made by the speaker(s): Nothing to disclose. Analysis. Answers. Action. 2

3 Objectives Multidrug-resistant organisms (MDROs) 1. Address the new challenges in detection of certain MDROs 2. Recognize the importance of accurate detection and reporting of these organisms 3

4 4 Bruce McCall, The New Yorker, 2008

5 Multidrug-resistant Organisms Organisms that are resistant to one or more classes of antimicrobial agents Methicillin-resistant Staphylococcus aureus Vancomycin-resistant Enterococcus Extended-spectrum β-lactamases (ESBLs) Carbapenem-resistant Organisms (Enterobacteriaceae, Acinetobacter baumannii, Pseudomonas aeruginosa) Healthcare Infection Control Practices Advisory Committee (HICPAC) - Management of Multidrug- Resistant Organisms in Healthcare Settings,

6 Multidrug-resistant Organisms Organisms that are resistant to one or more classes of antimicrobial agents Methicillin-resistant Staphylococcus aureus Vancomycin-resistant Enterococcus Extended-spectrum β-lactamases (ESBLs) Carbapenem-resistant Organisms (Enterobacteriaceae, Acinetobacter baumannii, Pseudomonas aeruginosa) Healthcare Infection Control Practices Advisory Committee (HICPAC) - Management of Multidrug- Resistant Organisms in Healthcare Settings,

7 Why is detection of MDROs important? MDROs have increased in prevalence over the past three decades in the U.S. MDROs are associated with Increased mortality Increased length of stay and increased costs Offer appropriate individualized patient treatment Control the spread of organisms Centers for Disease Control and Prevention. Antibiotic Resistance Threats in the United States, 2013 Marchaim D et al. Antimicrob Agents Chemother. 2008; 52:1413 7

8 Carbapenem-resistant Organisms 8

9 Ambler Classification of β-lactamases Molecular Class A B C D Enzymes TEM, SHV, CTX-M, KPC, GES, SME, IMI, NMC NDM, IMP, VIM, SPM, SIM, GIM AmpC, CMY-10 OXA Red = Carbapenemases 9

10 Klebsiella pneumoniae Carbapenemases (KPCs) Class A β-lactamases Enterobacteriaceae and non- Enterobacteriaceae KPC-2 through KPC-23 bla KPC gene Plasmid allows for horizontal gene transfer Encodes for resistance to other antimicrobial classes 10

11 Metallo-β-lactamases (MBLs) Class B β-lactamases P. aeruginosa, A. baumannii, Enterobacteriaceae Require zinc to catalyze hydrolysis of antimicrobials New Delhi Metallo-β-lactamases (NDMs) Located on very mobile genetic element Carry additional resistance genes Reservoirs colonized or infected persons on Indian subcontinent, also Middle East and Balkan countries Yong D et al. Antimicrob Agents Chemother. 2009; 53:

12 Oxacillinases (OXAs) Class D β-lactamases Oxacillin- and cloxacillin-hydrolyzing Most are plasmid-encoded Enterobacteriaceae, P. aeruginosa, A. baumannii 488 OXA enzymes, many of which are carbapenemases 12

AmpC β-lactamases Class C β-lactamases SPACE/SPICE organisms Hydrolyze cephalosporins, cephamycins (cefoxitin or cefotetan), aztreonam Most are not

13 AmpC β-lactamases Class C β-lactamases SPACE/SPICE organisms Hydrolyze cephalosporins, cephamycins (cefoxitin or cefotetan), aztreonam Most are not carbapenemases AmpC-expressing organisms can be resistant to carbapenems due to co-existent porin changes Very low hydrolysis rates for cefepime, carbapenems 13

14 Question 1 Which confirmatory test for suspected carbapenemase production is now described in the new CLSI M100-S25 document? A. A multiplex 17-target molecular assay for resistance determinants B. MBL Etest C. Carba NP test D. MALDI-TOF MS CLSI. M100-S25. Performance Standards for Antimicrobial Susceptibility Testing; 25 th Informational Supplement,

15 Question 1 Which confirmatory test for suspected carbapenemase production is now described in the new CLSI M100-S25 document? A. A multiplex 17-target molecular assay for resistance determinants B. MBL Etest C. Carba NP test D. MALDI-TOF MS CLSI. M100-S25. Performance Standards for Antimicrobial Susceptibility Testing; 25 th Informational Supplement,

16 Detection of CROs Detection of carbapenemases Modified Hodge test Enzymatic carbapenemase detection (i.e. Carba NP) MALDI-TOF MS Characterization of type of carbapenemase Inhibition-based phenotypic assays Molecular-based assays 16

17 Modified Hodge Test Pos Ctl Enterobacter AmpC patient-1 patient-2 Neg Ctl Slide courtesy of Dr. Paul Schreckenberger Carbapenem inactivation test Not specific for carbapenemases AmpC plus efflux pump or porin loss may be positive Sensitivity % Useful for Enterobacteriaceae False negative results have been demonstrated with bla NDM-1 strains Mochon AB et al. J Clin Microbiol. 2011; 49:

18 Carba NP Assay CLSI M100-S25 includes more options for identification of carbapenemase-producing organisms Two-hour tube test Imipenem is hydrolyzed which leads to a color change Identifies carbapenemase production in Enterobacteriaceae, P. aeruginosa and Acinetobacter spp. CLSI. M100-S25. Performance Standards for Antimicrobial Susceptibility Testing; 25 th Informational Supplement. Nordmann P et al. Emerg Infect Dis. 2012; 18:

19 Carba NP Solution A = phenol red, zinc sulfate, sodium hydroxide Solution B = Solution A plus imipenem Positive if B tube is yellow compared to A tube 19

20 CLSI Multi-center Carba NP Study 80 gram-negative bacteria (66 Enterobacteriaceae) 44 positive for carbapenemases and 36 negative for carbapenemases Isolates Results 14 NDM Most detected; 2 sites missed 2 NDMs 8 VIM All detected 4 IMP 2 sites missed one IMP 2 SME All detected 10 KPC Most detected; Missed 2 KPCs with low carbapenem MICs* 5 OXA-48 Only 2 were detected Limbago B et al. Multicenter Evaluation of a Rapid Test for Detection of Carbapenemase Production for Development of a CLSI-Endorsed Method. ICAAC

21 CLSI M100-S25 Under Table 2A Laboratories using Enterobacteriaceae MIC interpretive criteria for carbapenems described in M100-S20 should perform the MHT, the Carba NP test, and/or a molecular assay when isolates of Enterobacteriaceae are suspicious for carbapenemase production based on imipenem or meropenem MICs of 2-4 µg/ml or ertapenem MIC of 2 µg/ml. After implementation of the current interpretive criteria, the MHT does not need to be performed other than for epidemiological or infection control purposes. 21

Other Enzymatic Carbapenemase Tests Blue-Carba

range for most β- lactamases Rosco Diagnostica

Rapid Carb Screen (Rosco) with diatabs Imipenem plus

22 Other Enzymatic Carbapenemase Tests Blue-Carba Bromothymol blue indicator includes the optimal ph range for most β- lactamases Rosco Diagnostica (Denmark) Carba Blue RAPIDEC CARBA NP (biomérieux) Rapid Carb Screen (Rosco) with diatabs Imipenem plus indicator in a tablet form Pires J et al. J Clin Microbiol. 2013; 51:

23 Other Enzymatic Carbapenemase Test Rosco Neo-Rapid CARB kit (Key Scientific Products) FDA-approved* Enterobacteriaceae and P. aeruginosa Uninterpretability issues *Note correction: During this APHL talk on multidrug resistant organisms, I relayed some incorrect information regarding the Neo Rapid CARBA NP kit from Rosco. The information I relayed was based on the announcement made by Key Scientific Company about FDA clearance/approval. I have since learned that the kit is NOT FDA cleared or FDA approved. I apologize for this misrepresentation of the information. Audrey N. Schuetz, MD, MPH, D(ABMM), FCAP Time Read Sensitivity Specificity Carba NP 60 minutes Neo-Rapid CARB 100 minutes minutes minutes minutes Denis CJ et al. Preliminary comparison of Carba NP test and ROSCO Neo-Rapid CARB Screen kit. ECCMID

24 Advantages of Enzymatic Tests Rapid Positive results in 10 minutes to 2 hours Negative results in 2 hours Useful for a variety of GNRs but depends on kit Sensitivity and specificity approximately 90% Disadvantages of Enzymatic Tests Carba NP Special reagents required In-house preparation Short shelf life of Solution B Subjective color determination of some assays Limited ability to detect OXA enzymes Few FDA-approved tests 24

25 MALDI-TOF MS Carbapenem Hydrolysis Incubate a fresh bacterial culture with carbapenem solution Measure the degradation products compared to carbapenem alone Automated software are not currently available for analysis of spectra Chong PM et al. J Microbiol Methods. 2015; 111:21 Hrabák J et al. J Clin Microbiol. 2012; 50:

26 Characterization of the Type of β- lactamases 26

KPC Detection Using Boronic Acidbased Tests KPCs are inhibited by boronic acid Meropenem is tested with and without boronic acid High sensitivity

27 KPC Detection Using Boronic Acidbased Tests KPCs are inhibited by boronic acid Meropenem is tested with and without boronic acid High sensitivity for KPC Isolates with AmpCs plus porin losses may also test positive Rosco Diagnostica KPC/MPL disk kit Doi Y et al. J Clin Microbiol. 2008; 46:

28 MBL Detection Using Chelating Agents MBLs are inactivated by chelating compounds that deprive the organism of zinc Chelating compounds include mercaptopropionic acid, EDTA, dipicolinic acid MPI MP 28

29 Positive MBL Mastdiscs Group Mercaptopropionic Acid TE 2-MPA IP IP = Imipenem TE = EDTA 29

30 EDTA as Indicator of MBL EDTA can show moderate to poor specificity as an indicator of MBL Other β-lactamases can be positive Permeability action on outer membrane Study of EDTA and other phenotypic methods Isolates: 34 KPC, 21 VIM, 4 IMP, 9 OXA, 9 AmpC, 9 ESBL Positive by EDTA test: 4/34 KPC, 1/9 ESBL, 4/9 OXA-48 K. pneumoniae Giske CG et al. Clin Microbiol Infect. 2011; 17:552 30

31 MAST AmpC Kit Detects plasmid and chromosomally mediated E. coli and Klebsiella spp. Good performance for detection of AmpCs in Enterobacteriaceae Halstead FD et al. J Antimicrob Chemother. 2012; 67:

32 mastdiscs Carbapenemase detection (MBL and KPC) Enterobacteriaecae Some limitations in detection of OXAs Add temocillin 30 µg disc If resistant to temocillin, probably OXA-48 Recent study demonstrated 91% sensitivity for detection of KPC and MBL Different sensitivity based on different enzymes Saito R et al. J Microbiol Methods. 2015; 108:45 32

33 Limitations of Inhibition-based Disk Assays Interpretation can be subjective and requires some experience Most methods require overnight incubation Multiple methods should be used if more than one resistance mechanism is suspected For instance, if KPC and AmpC is suspected, cannot rely upon boronic acid alone 33

34 Genotypic Testing Relatively rapid Target-driven Panels directly from positive blood cultures can detect a variety of targets Commercial products are available for detection directly from colonies Labor-intensive for the routine clinical microbiology laboratory (RUO) BD Max CRE assay KPC, NDM, OXA-48 Check-Points (Netherlands) rapid molecular detection within 2 hours KPC, VIM, NDM, OXA-48, OXA minute multiplex assay by Streck (Omaha, NE) 9 targets (AmpC, MBL, KPC, ESBL, OXA-48) Philisa thermocycler 34

35 Question 2 A 68 year old patient from India has a blood culture positive for carbapenem-resistant Klebsiella pneumoniae. In which situation below might it be appropriate to assess whether this isolate possesses an NDM-1? A. The physician wishes to treat with ceftazidimeavibactam. B. The physician wishes to treat with polymyxin B. C. Infection control wishes to place this patient on contact precautions. D. There is never a need to differentiate among different carbapenemase mechanisms. 35

36 Question 2 A 68 year old patient from India has a blood culture positive for carbapenem-resistant Klebsiella pneumoniae. In which situation below might it be appropriate to assess whether this isolate possesses an NDM-1? A. The physician wishes to treat with ceftazidimeavibactam. B. The physician wishes to treat with polymyxin B. C. Infection control wishes to place this patient on contact precautions. D. There is never a need to differentiate among different carbapenemase mechanisms. 36

37 Should We Differentiate Among Carbapenem-resistant Gramnegative β-lactamases? 37

38 Ceftolozane-tazobactam (Cubist) Received FDA approval for complicated UTI and complicated intra-abdominal infections Ceftolozane is more active than ceftazidime against P. aeruginosa Doesn t cover KPC or MBL Upcoming ventilator-associated pneumonia trial 38

39 Ceftazidime-avibactam (Actavis) For treatment of complicated intraabdominal infections (with metronidazole) and complicated UTIs Enterobacteriaceae and P. aeruginosa Active against ESBLs and KPCs and OXA-48 Not active against MBLs or strains with both a KPC and AmpC Vazquez JA et al. Curr Med Res Opin. 2012; 28:1921 Lucasti C et al. J Antimicrob Chemother. 2013; 68:

40 Plazomicin (Achaogen) Novel, semi-synthetic aminoglycoside (neoglycoside, formerly ACHN-490) Active against aminoglycoside-modifying enzymes Undergoing phase III trials for CRE bacteremia and pneumonia Does not cover NDM Low to no nephrotoxicity or ototoxicity Zhanel GG et al. Expert Rev Anti Infect Ther. 2012; 10:459 40

41 Aztreonam-avibactam (AstraZeneca) Potentially adds MBLs to the spectrum Avibactam is active against other hydrolyzing enzymes (such as AmpCs and ESBLs) which are carried by organisms that also carry MBLs Protective against KPCs, some OXAs Just completed Phase I trial 41

42 Carbavance (Rempex, Medicines Co.) Novel β-lactamase inhibitor (RPX7009) with a carbapenem RPX2009 novel boronate Combined with biapenem Undergoing Phase III clinical trials for a variety of infections due to KPC-producing bacteria Most OXA-positive organisms will be affected by Carbavance MBLs are unaffected 42

43 Activity Against Various β-lactamases KPC AmpC OXA MBL Ceftolozane-tazobactam N +/- Y N Ceftazidime-avibactam Y +/- +/- N Aztreonam-avibactam Y Y Y Plazomicin Y N* Carbavance Y Y N *Not active against NDM but retains activity against some VIMs 43

44 MRSA 44

45 Question 3 55 year old female is admitted to a German hospital with fever and vomiting. Blood cultures are positive for gram-positive cocci in clusters. Rapid blood culture PCR was positive for S. aureus and negative for meca. The isolate was resistant to oxacillin (MIC 8 mcg/ml) and to cefoxitin (MIC 16 mcg/ml). A PBP2a test was negative. What is explanation? A. The PCR was incorrect. B. This is a heterogeneous population of MRSA and MSSA. C. The organism possesses the mecc gene. D. The organism is actually coagulase-negative Staphylococcus which relies on a mechanism other than meca for resistance. Adapted from pathquestions.com 45

46 Question 3 55 year old female is admitted to a German hospital with fever and vomiting. Blood cultures are positive for gram-positive cocci in clusters. Rapid blood culture PCR was positive for S. aureus and negative for meca. The isolate was resistant to oxacillin (MIC 8 µg/ml) and to cefoxitin (MIC 16 µg/ml). A PBP2a test was negative. What is explanation? A. The PCR was incorrect. B. This is a heterogeneous population of MRSA and MSSA. C. The organism possesses the mecc gene. D. The organism is actually coagulase-negative Staphylococcus which relies on a mechanism other than meca for resistance. Adapted from pathquestions.com 46

New Challenges in MRSA Detection mecc meca homologue (meca LGA251 ) with 69% identity Phenotypically methicillin resistant but negative by PCR

47 New Challenges in MRSA Detection mecc meca homologue (meca LGA251 ) with 69% identity Phenotypically methicillin resistant but negative by PCR for meca Encodes the PBP2c protein and confers resistance to all β-lactams except ceftaroline Saeed K et al. Curr Opin Infect Dis. 2014; 27:130 47

48 mecc Cryptic Resistance Negative for meca by PCR Negative for PBP2a May be oxacillin susceptible (MIC 2 µg/ml) May or may not grow on chromogenic MRSA selective media Cuny et al. PLoS ONE. 2011; 6:e

49 mecc Cefoxitin resistant Vitek 2 study: 55/62 strains with mecc were oxacillin susceptible and cefoxitin resistant Usually susceptible to non β-lactam antibiotics Newer platform can detect mecc BD MAX MRSA XT Assay with extended Detection Technology (FDA-cleared) Cartwright EJ et al. J Clin Microbiol. 2013; 51:

50 mecc Reported in 2007 from milk tanks of a UK dairy herd Primarily in Europe, usually in animals Ruminants, pigs, veal calves, poultry Colonizes humans but can also cause disease Primarily skin and soft tissue infections but also bacteremia, osteomyelitis Does not carry many toxins Denmark 2% of human MRSA cases are mecc Petersen A et al. Clin Microbiol Infect. 2013; 19:E16 Concepciόn Porrero M et al. Environ Microbiol Rep. 2014; 6:705 50

51 Conclusions Organisms are evolving genetic machinery to avoid antibiotics But, we are developing new antimicrobials Rapidity of results and accuracy of testing is important for both patient care and public health reasons Choice of testing methods varies based upon laboratory expertise, geographic area and relative prevalence of various β-lactamases Reporting the type of carbapenemase or β- lactamase may be important for treatment purposes 51

52 References 1. CLSI. M100-S25. Performance Standards for Antimicrobial Susceptibility Testing; 25 th Informational Supplement, Hrabák J, Chudáčková E, Papagiannitsis CC. Detection of carbapenemases in Enterobacteriaceae: a challenge for diagnostic microbiological laboratories. Clin Microbiol Infect. 2014; 20: Saeed K, Marsh P, Ahmad N. Cryptic resistance in Staphylococcus aureus: a risk for the treatment of skin infection? Curr Opin Infect Dis. 2014; 27:

53 Questions? Analysis. Answers. Action. 53

Use of Molecular Assays for Resistance Detection

Use of Molecular Assays for Resistance Detection Antimicrobial resistance and susceptibility are complex, and current in vitro methods have been developed to predict a microorganism s response to antibacterial