Antimicrobial activity of wound antiseptics against Extended-Spectrum Beta-Lactamase-producing bacteria

Abstract It was the aim of this study to investigate whether Extended-Spectrum-Beta-Lactamase (ESBL)-producing clinical isolates of Klebsiella pneumoniae and Escherichia coli are displaying greater resistance to the active ingredients octenidine dihydrochloride (OCT), chlorhexidine digluconate (CHG) and polyhexamethylen biguanide (PHMB) compared to type strains usually tested in laboratories and are therefore not killed to an adequate extent despite the use of recommended concentrations. OCT showed a balanced growth inhibition of all strains from 4 to 8 mg/L. The MICs obtained with CHG and PHMB were heterogeneous between 3.1 and 200 mg/L. In quantitative suspension tests OCT was highly effective within the shortest contact times, CHG and PHMB needed longer contact times to obtain a sufficient germ reduction. However, all active agents tested were able to kill ESBL-producing bacteria sufficiently at concentrations far below those concentrations that are usually applied in wound treatment. In conclusion, our in vitro data demonstrate that commonly used wound antiseptic agents are effective against ESBL-producing bacteria. Furthermore, no influence of the antibiotic-resistance on the efficacy of the antiseptic agents tested or a higher resistance against strains used in standard methods could be observed.