RESUMEN
A continuous surveillance on N.I. was done in Lampang Hospital from October 1988 to March 1990. The incidence rate of N.I. in 58,355 patients was 3.5 per cent. The average duration of hospital stay was 20.5 days. The highest infection rate was found in intensive care units followed by the surgical and orthopaedic departments (16.8, 5.9, 5.0 per cent) respectively. Urinary tract was the commonest site (19.4 per cent), followed closely by surgical wound, skin and lower respiratory infections. The infection rate was highest in patients aged 25-44 years and the common causative bacteria were Pseudomonas species, Escherichia coli and Klebsiella species. During the study there were two outbreaks of N.I., namely eye infection and diarrhoea. Both were brought under control by simple measures. Excessive use of antimicrobials was also revealed in the study.