Correlation between consumption of antimicrobials in humans and development of resistance in bacteria

The correlation between consumption of antimicrobials in humans and the emergence of resistance in bacteria is complex and has proved difficult to establish. Besides antimicrobial use, many other distinct contributing factors are also involved in the issue. Despite this complexity, there is a substantial body of evidence that the use of antibiotics in prophylaxis and in therapy is associated with the development of resistance in the hospital and in the community. Some examples are reviewed, including increase of resistance in enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter spp., Streptococcus pneumoniae, Staphylococcus aureus, Coagulase Negative Staphylococci and Streptococcus pyogenes after the use of beta-lactam antibiotics, aminoglycosides, fluoroquinolones and macrolides. Success in reversing the rise of resistant strains has been rarely described. Two examples are highlighted, the reduction in the incidence of nasal carriage of penicillin-resistant pneumococci in Icelandic children, and a significant decline in erythromycin resistance in S. pyogenes after the reduction in the use of macrolides in Finland.