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The prevalence of extended-spectrum β-lactamase (ESBL) genes has increased remarkably, resulting in multidrug-resistant gram-negative rods (GNRs) in clinical specimens. This cross-sectional study aimed to determine the antimicrobial susceptibility of ESBL-producing GNRs and its correlation with corresponding genes. Two hundred and seventy-two (<i>n</i> = 272) samples were evaluated for the molecular identification of ESBL genes by polymerase chain reaction after confirmation with the modified double-disc synergy test. <i>E. coli</i> 64.0% (<i>n</i> = 174) was the most prevalent ESBL producer, followed by <i>Klebsiella</i> species 27.2% (<i>n</i> = seventy-four), <i>Acinetobacter</i> species 6.6% (<i>n</i> = eighteen) and others 2.2% (<i>n</i> = six). These ESBL-producing isolates showed resistance to β-lactam antibiotics, i.e., sulbactam/cefoperazone (41.5%), piperacillin/tazobactam (39.3%), meropenem (36.0%), imipenem (34.2%) and non- β-lactam antibiotics, i.e., nalidixic acid (89.0%), co-trimoxazole (84.9%), ciprofloxacin (82.4%), gentamicin (46.3%), nitrofurantoin (24.6%), amikacin (19.9%) and fosfomycin (19.9%). The incidences of the ESBLs-producing genes <i>bla_CTX-M, bla_TEM</i>, <i>bla_OXA</i> and <i>bla_SHV</i> were 91.2%, 61.8%, 39.3% and 17.6%, respectively. Among nine multiple-gene combinations, <i>bla_CTX-M + bla_TEM</i> (30.5%) was the most prevalent combination, followed by <i>bla_CTX-M + bla_OXA + bla_TEM</i> (14.0%), <i>bla_CTX-M + bla_OXA</i> (13.6%), <i>bla_CTX-M + bla_TEM + bla_SHV</i> (7.0%), <i>bla_CTX-M + bla_SHV</i> (2.2%), <i>bla_CTX-M + bla_OXA + bla_SHV</i> (2.2%) and <i>bla_OXA + bla_TEM</i> (1.8%). ESBLs producing GNRs carrying <i>bla_CTX-M, bla_TEM</i>, <i>bla_OXA</i> and <i>bla_SHV</i> showed resistances to β-lactam antibiotics, i.e., ampicillin, amoxillin-clavulanic acid, cefotaxime and ceftazidime but were susceptible to carbapenems (meropenem and imipenem), β-lactam-β-lactamase inhibitor combination (piperacillin/tazobactam) and non-β-lactam antibiotics i.e., aminoglycoside (amikacin and gentamicin), nitrofurantoin and fosfomycin. These antibiotics that demonstrated activity may be used to treat infections in clinical settings.