ABSTRACT

Introduction The clinical assessment of a patient should influence correct antibiotic prescription. It is therefore important to have an appreciation of the bacteria that are likely to be causing a particular infection. For example, one organism such as meningococcus may be considered in a case of bacterial meningitis and a single antibiotic such as cefotaxime prescribed. In peritonitis due to a ruptured colonic diverticulum, all the bacteria of the bowel flora should be considered. Agents effective against grampositive streptococci, gram-negative ‘coliforms’, and gram-positive and gram-negative anaerobes would be prescribed. Cefuroxime and metronidazole, or three agents such as ampicillin, gentamicin, and metronidazole,

can be used. Another alternative would be a broadspectrum agent such as co-amoxiclav, which may be given in combination with gentamicin. Any regime needs to be modified when bacteria are isolated from specimens and when it is clinically appropriate to do so.