Laboratory Detection of ExtendedSpectrum Lactamases ESBLs

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Laboratory Detection of Extended-Spectrum
ß-Lactamases (ESBLs)

• Dr. TRAÀN THÒ NGOÏC ANH

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What are extended-spectrum ß-lactamases?

• ESBLs are enzymes that mediate resistance to
  extended-spectrum (third generation)
  cephalosporins (e.g., ceftazidime, cefotaxime,
  and ceftriaxone) and monobactams (e.g.,
  aztreonam)
• but do not affect cephamycins (e.g., cefoxitin
  and cefotetan) or carbapenems (e.g., meropenem or
  imipenem).

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Why should clinical laboratory personnel be
concerned about detecting these enzymes?

• The presence of an ESBL-producing organism in a
  clinical infection can result in treatment
  failure if one of the above classes of drugs is
  used.
• ESBLs can be difficult to detect because they
  have different levels of activity against various
  cephalosporins.

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• Thus, the choice of which antimicrobial agents to
  test is critical.
• For example, one enzyme may actively hydrolyze
  ceftazidime, resulting in ceftazidime minimum
  inhibitory concentrations (MICs) of 256 µg/ml,
  but have poor activity on cefotaxime, producing
  MICs of only 4 µg/ml.

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• If an ESBL is detected, all penicillins,
  cephalosporins, and aztreonam should be reported
  as resistant, even if in vitro test results
  indicate susceptibility (1).

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How can clinical laboratory personnel screen for
ESBL production in bacteria?

• The National Committee for Clinical Laboratory
  Standards (NCCLS) has developed broth
  microdilution and disk diffusion screening tests
  using selected antimicrobial agents (1).
• Each Klebsiella pneumoniae, K. oxytoca, or
  Escherichia coli isolate should be considered a
  potential ESBL-producer if the test results are
  as follows

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• The sensitivity of screening for ESBLs in enteric
  
• organisms can vary depending on which
  antimcrobial
• agents are tested.
• The use of more than one of the five
  antimicrobial
• agents Suggested for screening will improve the
  
• sensitivityof detection.
• Cefpodoxime and ceftazidime show the highest
• sensitivity for ESBL detection.

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Confirmatory tests for ESBLSDOUBLE DISC TESTS
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• Confirmatory tests for ESBLS
• COMBINATION DISC METHODS

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Confirmatory tests ESBLS Etest ESBL strips
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• Can an ESBL be present in an isolate of K.
  pneumoniae that is resistant to ceftazidime
  and/or cefotaxime, but demonstrates no clavulanic
  acid effect in the phenotypic confirmatory test
• The phenotypic confirmatory test does not detect
  all ESBLs.

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• Some organisms with ESBLs contain other
  ß-lactamases that can mask ESBL production in the
  phenotypic test, resulting in a false-negative
  test..
• These ß-lactamases include AmpCs and
  inhibitor-resistant TEMs (IRTs). Hyper-production
  of TEM and/or SHV ß-lactamases in organisms with
  ESBLs also may cause false-negative phenotypic
  confirmatory test results

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• Currently, detection of organisms with multiple
  ß-lactamases that may interfere with the
  phenotypic confirmatory test can only be
  accomplished using isoelectric focusing and DNA
  sequencing, methods that are not usually
  available in clinical laboratories.

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How should cephalosporin and penicillin results
be reported?

• If an isolate is confirmed as an ESBL-producer by
  the NCCLS-recommended phenotypic confirmatory
  test procedur
• all penicillins, cephalosporins, and aztreonam
  should be reported as resistant.

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• This list does not include the cephamycins
  (cefotetan and cefoxitin), which should be
  reported according to their routine test
  results. 
• Do not change interpretations of penicillins,
  cephalosporins, and aztreonam for isolates not
  confirmed as ESBLs.
• Content source  Division of Healthcare Quality
  Promotion (DHQP)National Center for
  Preparedness, Detection, and Control of
  Infectious Diseases

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T?n su?t vi khu?n ti?t ESBL vùng châu Á-Thái bình
duong
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T?n su?t vi khu?n ti?t ESBL vùng châu Á-Thái bình
duong
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T?n su?t vi khu?n ti?t ESBL vùng châu Á-Thái bình
duong
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Tính nh?y c?m ks c?a vi khu?n du?ng ru?t ti?t
ESBL vùng châu Á-Thái bình duong
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Tính nh?y c?m ks c?a E coli ti?t ESBL vùng châu
Á-Thái bình duong
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Tính nh?y c?m ks c?a K pneumoniae ti?t ESBL vùng
châu Á-Thái bình duong
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Tính nh?y c?m ks c?a E cloacae ti?t ESBL vùng
châu Á-Thái bình duong
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T? l? kháng cephalosporin SMART BV CH? R?Y 2006

• Cefepime 25
• Ceftazidime 12
• Cefotaxime 32
• Ceftriaxone 32

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Y NGHIA LS NHIEM KHUAN TIET ESBL

• NKH
• -TI LE SONG 71 VS 84 (Henshke-Bar-Meir,
  Irael, 2006)
• -Ty le chet 25,6 (oh, Korea, 2004)
• -Ty le chet 30 vs 16 (Schwaber, Tel Avi,
  2006)

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ESBL ? Vi?t Nam

• Eco 33,6 - Kpn 34,5
• 51,6 61,7
• 18,5 20,1
• 39,6 46,4
• 33,6 34,5
• 36,2 19,6
• 41,5 53,6
• 21,3 32,7

• ASTS 2004
• Ch? R?y 2005
• B?ch Mai 2005
• Vi?t Ð?c 2006
• Vi?t Ti?p 2006
• Bình Ð?nh 2005
• T U Hu? 2006
• BV NHI ÑOÀNG 2 2006

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CAÙC CHUÛNG VI KHUAÅN GRAM AÂM SINH ESBL ÑAÕ
BIEÁT

• Escherichia coli.
• Klebsiella pneumoniae, Klebsiella cryocrescens,
  Klebsiella ascorbata, Klebsiella georgiana,
  Klebsiella ozaenae.
• Proteus mirabilis, Proteus penneri, Proteus
  vulgaris.
• Morganella morganii.
• Providencia stuartii.
• Enterobacter aerogenes, Enterobacter cloacae,
  Enterobacter gergoviae.
• Citrobacter freundii, Citrobacter amalonaticus,
  Citrobacter koserii, Citrobacter diversus.
• Serratia marcescens, Serratia fonticola,
  Serratia rubidaea.
• Shigella flexneri, Shigella sonnei.
• Salmonella enteritica typhimurium, Salmonella
  virchow, Salmonella spp.
• Acinetobacter baumannii, Acinetobacter spp.
• Aeromonas hydrophilia.
• Vibrio cholerae
• Yersinia enterocolitica
• Stenotrophomonas maltophilia
• Pseudomonas aeruginosa, Burkholderia cepacia,
  Pseudomonas spp.
• Chryseobacterium (Flavobacterium)
  meningosepticum.

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Khuy?n cáo di?u tr? nhi?m khu?n ti?t ESBL

• Không di?u tr? vi khu?n t?p trú (colonization)
• Imipenem / meropenem nhi?m khu?n huy?t, viêm
  ph?i do máy th?, ch?ng gi?m nh?y ertapenem
• Ertapenem nhi?m khu?n ti?t ni?u có bi?n ch?ng, ?
  b?ng, bàn chân ti?u du?ng
• Quinolone d? ?ng carbapenem
• Nitrofurantoin / fosfomycin nhi?m khu?n du?ng
  ti?u du?i không bi?n ch?ng
• Tigecyclin, colistin, polymyxin B kháng da kháng
  sinh khác.

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Toùm taét caùc can thieäp coù theå duøng ñeå
ngöøa caùc nhieãm khuaån do vi khuaån saûn xuaát
ESBL ôû beänh nhaân naèm vieän

• Traùnh duøng cephalosporin theá heä 3, aztreonam,
  hay cefuroxime
• Traùnh ñaët caùc thieát bò xaâm nhaäp nhö oáng
  thoâng tieåu, hay ñöôøng truyeàn tónh maïch
• Ñaûm baûo baøn tay saïch tröôùc vaø sau khaùm
  treân beänh nhaân

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• Giôùi haïn duøng cephalosporin theá heä 3
• Caùch ly vaø löu yù caùc beänh nhaân mang hay bò
  nhieãm khuaån ESBL
• Khaûo saùt söï nhieãm khuaån moâi tröôøng neáu
  xaûy ra söï gia taêng vi khuaån ESBL

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C?m on