For debate The problem with cephalosporins

Although widely accepted as broad-spectrum antibiotics, cephalosporins are not active against all the bacteria commonly isolated in a hospital microbiology laboratory. Organisms that are not inhibited by cephalosporin therapy consequently overgrow, with varying potential to cause infection. Some of these are instantly recognizable as pathogens; others, although originally regarded as commensal or of low risk status, have subsequently been shown to cause disease. Furthermore, there is an association between cephalosporin usage and the emergence of multiply-resistant organisms. Microorganisms selected by cephalosporin therapy include commensal organisms such as coagulase-negative staphylococci (CNS), Pseudomonas aeruginosa, enterococci and Candida albicans, and organisms of more established pathogenicity, e.g. Clostridium difficile, penicillinresistant pneumococci, multiply-resistant coliforms and methicillin-resistant Staphylococcus aureus (MRSA). Some of these organisms are constitutively resistant to cephalosporins while others have acquired resistance, usually as part of a multiple resistance package. This review discusses the evidence for a link between cephalosporins and overgrowth of certain microorganisms, including those that are multiply resistant to antibiotics.