TABLE 1.

Numbers of ESBL-producing E. coli and Klebsiella sp. isolates

Yr of isolation	E. coli					Klebsiella spp.
	No. of clinical isolates	No. (%) of ESBL producers	CTX-M group 1/ group 9	% of CTX-M enzymes among ESBLs	% of non-CTX-M enzymes among ESBLs	No. of clinical isolates	No. (%) of ESBL producers	CTX-M group 1/ group 9	% of CTX-M enzymes among ESBLs	% of non-CTX-M enzymes among ESBLs
1998	5,004	3 (0.06)	0/0	0	100	1,059	16 (1.5)	0/0	0	100
1999	5,300	2 (0.04)	0/1	50	50	1,140	12 (1)	1/0	8	92
2000	4,636	6 (0.13)	2/0	33.3	66.6	938	11 (1.2)	0/0	0	100
2001	6,382	3 (0.05)	1/0	33.3	66.6	1,114	15 (1.3)	0/0	0	100
2002	6,685	7 (0.1)	4/0	57.1	42.9	1,129	7 (0.6)	2/0	28.6	70.4
2003	7,004	19 (0.3)	11/2	68.4	31.6	1,163	8 (0.7)	0/1	12.5	87.5
2004	7,259	20 (0.3)	12/5	85	15	1,209	20 (1.6)	5/1	30	70
Total	42,270	60	30/8	36.6	63.3	7,752	89	8/3	12.4	87.6