Phenotypic Characterization and Antibiotic Resistance Patterns of Extended-Spectrum β-Lactamase- and AmpC β-Lactamase-Producing Gram-Negative Bacteria in a Referral Hospital, Saudi Arabia

Table 3

Antibiotic resistance patterns of Gram-negative bacteria producing ESBLs and AmpC β-lactamases compared to nonproducer isolates.

Antibiotic	Total number of Gram-negative rods (n = 311)		value	Total number of Gram-negative rods (n = 311)		value
	Non-ESBL (n = 227)	ESBL (n = 84)		AmpC (n = 101)	Non-AmpC (n = 210)
Amikacin	31 (36.9)	61(26.9)	0.085	57 (56.4)	35 (16.7)	<0.001
Tobramycin	50 (42)	92 (40.5)	0.134	67 (66.3)	67 (31.9)	<0.001
Gentamicin	40 (47.6)	81 (35.7)	0.055	66 (65.3)	55 (26.2)	<0.001
Amoxicillin/clavulanate	58 (69)	91 (40.1)	<0.001	93 (92.1)	56 (26.7)	<0.001
Cefuroxime	81 (96.4)	137 (60.4)	<0.001	92 (91.1)	126 (60)	<0.001
Ceftazidime	72 (85.7)	76 (33.5)	<0.001	65 (64.4)	83 (39.5)	<0.001
Cefotaxime	78 (92.9)	85 (37.4)	<0.001	76 (75.2)	87 (41.4)	<0.001
Cefepime	75 (89.3)	87 (38.3)	<0.001	75 (74.3)	87 (41.4)	<0.001
Meropenem	24 (28.6)	59 (26.0)	0.755	50 (49.5)	33 (15.7)	<0.001
Piperacillin	53 (63.1)	77 (33.9)	<0.001	72 (71.3)	58 (27.6)	<0.001
Piperacillin/tazobactam	42 (50)	77 (33.9)	0.010	65 (64.4)	54 (25.7)	<0.001
Imipenem	26 (31)	62 (27.3)	0.527	58 (57.4)	30 (14.3)	<0.001
Aztreonam	69 (82.1)	98 (43.2)	<0.001	82 (81.2)	85 (40.5)	<0.001
Ciprofloxacin	51 (60.7)	92 (40.5)	0.002	74 (73.3)	69 (32.9)	<0.001
Ofloxacin	50 (59.5)	91 (40.1)	0.002	70 (69.3)	71 (33.8)	<0.001
Nitrofurantoin	50 (59.5)	103 (45.4)	0.027	78 (77.2)	75 (35.7)	<0.001
Trimethoprim/sulfamethoxazole	76 (90.5)	140 (61.7)	<0.001	91 (90.1)	125 (59.5)	<0.001
Colistin	4 (4.8)	5 (2.2)	0232	7 (6.9)	2(1.0)	0.003