Table 4.

Risk factors for resistance to ciprofloxacin, resistance to gentamicin and multidrug resistance in 895 randomly selected E. coli isolates recovered from 208 chicken farms (Tien Giang province, Vietnam)

Outcome	Variable	OR	95% CI	P
Ciprofloxacin resistancea	small farm (baseline = household farm)	6.42	2.74–15.03	<0.001
	use of commercial feed	1.87	1.06–3.30	0.032
	change shoes/boots practice	2.43	1.44–4.09	<0.001
	AIAO system	0.17	0.02–1.28	0.086
	use of quinolones	2.26	1.20–4.25	0.011
	use of tetracyclines	1.70	1.05–2.76	0.031
	interaction ‘small farm’ and ‘change shoes/boots’	0.22	0.09–0.55	0.001
	interaction ‘use of commercial feed’ and ‘AIAO’	10.99	1.38–87.7	0.024
Gentamicin resistanceb	use of tetracyclines	1.99	1.17–3.36	0.011
	presence of cat(s)	0.44	0.24–0.82	0.010
	change shoes/boots practice	2.41	1.27–4.59	0.007
	day-old chickens from other sourcesc	4.93	1.22–19.97	0.026
	use of lincosamides	4.74	1.18–18.97	0.028
	log(density)d	1.32	1.02–1.69	0.034
	chicken purpose (baseline = egg-laying chicken)
	meat chicken	9.88	5.32–18.33	<0.001
	mixed chicken	5.03	1.81–14.01	0.002
Multidrug resistancee,f	use of commercial feed	2.49	1.14–4.14	0.001
	log(density)	1.28	1.06–1.54	0.008
	years of experience in chicken farming	0.96	0.93–0.99	0.004

^aIntercept: −2.60 (SEM ± 0.28).

^bIntercept: −5.79 (SEM ± 0.74).

^cBaseline = day-old chickens from industrial hatchery companies. Other sources include local hatcheries, markets and neighbours.

^dNumber of chickens per m².

^eIntercept: 1.41 (SEM ± 0.28).

^fResistant to at least three different classes of antimicrobial drugs.