1.第一類β-lactamases：cephalosporinases（以AmpC enzymes為典型），主要水解對象為Cephalosporins；clavulanic acid所產生的抑制活性並不高
2.第二類β-lactamases：涵蓋的範圍較為廣泛，以penicillinases, cephalosporinases, 和廣效型β-lactamases為主，且可被clavulanic acid抑制活性
3.第三類β-lactamases：metallob-lactamases以penicillins, cephalosporins, 和carbapenems為水解對象。這些β-lactamases的機能特色和胺基酸排列順序不同而產生分子結構差異互相關聯。其中又以TEM、SHV與OXA是ESBLs最常見的基因型態，分別歸類在classA與classD。
表一 β-lactamases 的分類
Bush-Jacoby-Medeiros group
|
1989 Bush group (44)
|
Richmond-Sykes class (253)
|
Mitsuhashi-Inoue type (194)a
|
分子分類
(2, 121, 132)
|
易被誘導物質
|
Inhibited by:
|
代表性的酵素
|
|
CAb
|
EDTA
|
|||||||
1
|
1
|
Ia, Ib, Id
|
CSase
|
C
|
Cephalosporins
|
-
|
-
|
AmpC enzymes from gramnegative bacteria; MIR-1
|
2a
|
2a
|
未包含
|
PCase V
|
A
|
Penicillins
|
+
|
-
|
Penicillinases from grampositive bacteria
|
2b
|
2b
|
III
|
PCase I
|
A
|
Penicillins, cephalosporins
|
+
|
-
|
TEM-1, TEM-2, SHV-1
|
2be
|
2b'
|
未包含except K1 in class IV
|
CXase
|
A
|
Penicillins, narrow-spectrum and extended-spectrum cephalosporins, monobactams
|
+
|
-
|
TEM-3 to TEM-26, SHV-2 to SHV-6, Klebsiella oxytoca K1
|
2br
|
未包含
|
未包含
|
未包含
|
A
|
Penicillins
|
+-
|
-
|
TEM-30 to TEM-36, TRC-1
|
2c
|
2c
|
II, V
|
PCase IV
|
A
|
Penicillins, carbenicillin
|
+
|
-
|
PSE-1, PSE-3, PSE-4
|
2d
|
2d
|
V
|
PCase II, PCase III
|
D
|
Penicillins, cloxacillin
|
+-
|
-
|
OXA-1 to OXA-11, PSE-2 (OXA-10)
|
2e
|
2e
|
1c
|
CXase
|
A
|
Cephalosporins
|
+
|
-
|
Inducible cephalosporinases from Proteus vulgaris
|
2f
|
未包含
|
未包含
|
未包含
|
A
|
Penicillins, cephalosporins, carbapenems
|
+
|
-
|
NMC-A from Enterobacter cloacae, Sme-1 from Serratia marcescens
|
3
|
3
|
未包含
|
未包含
|
B
|
Most b-lactams, including carbapenems
|
-
|
+
|
L1 from Xanthomonas maltophilia,
CcrA from Bacteroides fragilis |
4
|
4
|
未包含
|
未包含
|
NDc
|
Penicillins
|
-
|
?
|
Penicillinase from Pseudomonas
cepacia |
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