Table.

P value and Spearman's correlation coefficient (95% confidence interval) for use of antibiotics and rate of antibiotic resistance (excluding repeat isolates) among general practitioner surgeries in Wales, 1996-8

Antibiotic used	Ampicillin			Co-amoxiclav			Cephalosporin*			Trimethoprim			Ciprofloxacin			Mean (range) No of prescriptions/ 1000 patients/year		Mean (range) percentage of organisms resistant to antibiotics†
P value	rs	P value	rs	P value	rs	P value	rs	P value	rs
Amoxicillin	<0.001	0.394 (0.269 to 0.506)		0.659			0.527			0.015	0.172 (0.033 to 0.304)		0.376			352 (81-912)		53.2 (34.2-67.6)
Co-amoxiclav	0.576			0.714			0.145			0.936			0.309			75 (7-239)		8.4 (0.0-26.1)
Cephalosporin	0.108			0.753			0.018	0.167 (0.028 to 0.299)		0.134			0.478			107 (16-532)		6.5 (0.0-19.0)
Trimethoprim	0.004	0.204 (0.066 to 0.334)		0.003	0.229 (0.081 to 0.367)		0.001	0.230 (0.094 to 0.358)		<0.001	0.331 (0.201 to 0.450)		0.056			63 (13-215)		26.3 (12.7-44.3)
Quinolones	0.069			0.873			0.103			0.306			0.015	0.225 (0.045 to 0.391)		34 (7-96)		2.2 (0.0-10.1)
All antibiotics	<0.001	0.319 (0.188 to 0.439)		0.581			0.411			0.031	0.153 (0.014 to 0.286)		0.141			971 (400- 1739)

^*Resistance to cefalexin was identified at six laboratories and resistance to cefradine at one. 

^†Overall mean of resistance rates for individual surgeries based on number of isolates varying from 50 to about 800.