Excretion of beta-lactam antibiotics in sweat - a neglected mechanism for development of antibiotic resistance?

The concentrations of beta-lactam antibiotics after standard doses were mea sured in blood and apocrine (axilla) and eccrine (forearm) sweat from sis a dult healthy persons. All persons had ceftazidime (axilla, 28.4 mu g/ml; fo rearm, 11 mu g/ml) and ceftriaxone (axilla, 8.9 mu g/ml; forearm, 2.5 mu g/ ml) in sweat, and one person had cefuroxime in sweat (axilla, 7.8 mu g/ml) (all data are mean peaks). Three persons had benzylpenicillin (axilla, 2.6 to 0.1 mu g/ml) and one had phenoxymethylpenicillin (axilla, 0.4 mu g/ml) i n sweat. Excretion of beta-lactam antibiotics in the sweat may explain why staphylococci so rapidly become resistant to these drugs.