Fluoroquinolones and bacterial enteritis, when and for whom?

During the last decade quinolones such as norfloxacin, ciprofloxacin, ofloxacin and fleroxacin have emerged as drugs ofchoice for treatment of various bacterial enteric infections. Controlled studies have shown that quinolones, administered in varying regimens ranging from a single dose to 5 days treatment, significantly reduce the intensity and severity of travellers' diarrhoea as well as shigellosis. They have also been found to be highly effective in the treatment of invasive non-typhoid salmonellosis as well as typhoid fever. Results from trials evaluating quinolone treatment of uncomplicated salmonella and campylobacter enteritis have generally been disappointing. We studied norfloxacin for the empirical treatment of suspected bacterial enteritis of less than 6 days duration in a large placebo controlled trial. Although statistical differences in clinical outcome favouring norfloxacin were found among 259 culture positive patients, the differences were not striking and of doubtful clinical importance.However, a clear beneficial effect of norfloxacin, resembling that observed in early treatment of travellers' diarrhoae was found among the severely ill patients who initiated treatment within 48 h of onset of illness. Patients whose illness was present for > 48 h before starting treatment failed to show any clinical benefit from norfloxacin. Thus, the intervalfrom onset of symptoms to start of treatment seemed to be of major importance in relation to therapeutic efficacy. Quinolone treatment of bacterial enteritis is furthermore limited by the rapid development of resistance seen in Campylobacter spp. and the failure of these compounds to eradicate Salmonella spp. Presently quinolones can be recommended in treatment of travellers' diarrhoea and shigellosis as well as enteric fever.They have limited usefulness for the routine empirical treatment of bacterial enteritis caused by Salmonella spp and Campylobacter spp. Treatment should be restricted to early empirical treatment of the severely ill and vulnerable patients with an underlying health problem.