Ethambutol enhanced the effects of chlorhexidine diacetate and cetylpyridinium chloride against Mycobacterium avium, M. bovis BCG, M. fortuitum and M. phlei. The findings show that it is possible to increase the susceptibility of mycobacteria to agents that normally exhibit poor activity against these organisms because of their reduced cellular penetration.

The interactions of a series of alkyl pyridinium surfactants (alkyl chain lengths C-10 (DePB), C-12 (DoPB) and C-14 (TePB)) with liposomes modeling the stratum corneum (SC) lipid composition (40% ceramides, 25% cholesterol, 25% palmitic acid and 10% cholesteryl sulfate) were investigated. The surfactant:lipid molar ratios (Re) and the bilayer–aqueous phase partition coefficients (K) were determined by monitoring the changes in the static light scattering of the system during solubilization. The fact that the free concentration was always similar to the surfactant critical micelle concentration (CMC) indicates that liposome solubilization was mainly ruled by formation of mixed micelles. The Re and K values fell as the surfactant alkyl chain length decreased or their CMC increased. Thus, the higher the surfactant CMC the higher the surfactant ability to saturate or solubilize SC liposomes and the lower its degree of partitioning into liposomes. The balance of these two tendencies shows that the TePB and DoPB had respectively the highest power of saturation and solubilization of SC structures in terms of total surfactant amounts needed to produce these effects. Different trends in the interaction of these surfactants with SC liposomes were observed when comparing the Re and K values with those reported for PC ones. Thus, whereas SC liposomes were more resistant to the surfactant action, the degree of partitioning of these surfactants into these liposomes was higher in all cases.

The peroxygen-based disinfectant, ‘Virkon’ (at concentrations of 2, 3 and 4%) was tested against Mycobacterium tuberculosis and M. aviumintracellulare over exposure times ranging between 30 and 120 min. Two test procedures were used: (a) a standard plate method, (b) a method incorporating the use of the ‘Bactec’ 460 radiometric system to chart bacterial growth following exposure to ‘Virkon’. In our hands and under the conditions of the two test methods, ‘Virkon’ did not produce a satisfactory kill of the test strains over 60 or 120 min.

Journal Article Effects of Biocides on Mycobacteria Get access SJ Broadley, SJ Broadley Welsh School of Pharmacy, University of Wales College of Cardiff, Cardiff CF1 3XF Search for other works by this author on: Oxford Academic Google Scholar PA Jenkins, PA Jenkins Mycobacterial Reference Unit, University Hospital of Wales, Heath Park, Cardiff CF4 4XW, Wales Search for other works by this author on: Oxford Academic Google Scholar J R Furr, J R Furr Welsh School of Pharmacy, University of Wales College of Cardiff, Cardiff CF1 3XF Search for other works by this author on: Oxford Academic Google Scholar AD Russell AD Russell Welsh School of Pharmacy, University of Wales College of Cardiff, Cardiff CF1 3XF Search for other works by this author on: Oxford Academic Google Scholar Journal of Pharmacy and Pharmacology, Volume 42, Issue Supplement_1, December 1990, Page 107P, https://doi.org/10.1111/j.2042-7158.1990.tb14480.x Published: 12 April 2011