Laboratory acquired verotoxin producing Escherichia coli (VTEC) infection

Verotoxin-producing Escherichia coli (VTEC) have emerged as a significant public health problem in the UK. Between 1990 and 1993 the annual incidences of infections with VTEC in England, Scotland and Wales have ranged from 0.5 to 4.0 cases per 100 000 population. Clinical manifestations of the infection range from mild diarrhoea to life threatening haemorrhagic colitis. Haemolytic uraemic syndrome (HUS) develops in 2-7% of the patients, and is particularly common in children. The commonest VTEC responsible for human infections is E. coli O157:H7. Diagnosis of this infection is mainly by culture of E. coli O157:H7 from faeces of infected patients. Such tests are performed routinely in most microbiology laboratories in the UK. Although the risk of acquiring infections is inherent in handling infected material in a microbiology laboratory, introduction of many safe practices has resulted in such accidents happening only rarely. In this letter we report a serious laboratory acquired infection with E. coli O157:H7 in a laboratory worker. In the light of this and two other previously published reports, we propose that the hazard category of this organism is re-examined.