Table 1. Antibiotic resistance to ceftriaxone, ciprofloxacin, and colistin and the proportion of ESBL-producing isolates amongst resistant Escherichia coli, isolated from stool samples of 544 healthy adult workers containing 906 E. coli isolates.

Antibiotic resistance (by population)	No. of subjects (n  =  544)	Antibiotic resistance (by isolate)	No. of isolates (n  =  906)
Ceftriaxone resistance (MIC > 4) in any isolates, n (%)	424 (77.9)	Ceftriaxone resistance (MIC > 4) (by isolate)	493 (54.4)
Ciprofloxacin resistance (MIC > 4) in any isolates, n (%)	450 (82.7)	Ciprofloxacin resistance (MIC > 4)	550 (60.7)
Ceftriaxone and ciprofloxacin resistance in the same isolate, n (%)	86 (15.8)	Ceftriaxone and ciprofloxacin resistance in the same isolate	137 (15.1)
ESBL production in any isolates, n (%)	412 (75.5)	ESBL production in any isolates	429 (47.4)
		Colistin resistance (inhibition zone diameter < 11 mm)	(n  =  352) 31 (8.8)

ESBL: extended-spectrum beta-lactamase; MIC: minimum inhibitory concentration.