White and blue light induce reduction in susceptibility to minocycline and tigecycline in Acinetobacter spp. and other bacteria of clinical importance.
Minocycline (MIN) and tigecycline (TIG) are antibiotics currently used for treatment of multidrug-resistant nosocomial pathogens. In this work, we show that blue light, as well as white light, modulates susceptibility to these antibiotics in a temperature-dependent manner. The modulation of susceptibility by light depends on the content of iron; an increase in iron results in a reduction in antibiotic susceptibility both under light and in the dark, though the effect is more pronounced in the latter condition. We further provide insights into the mechanism by showing that reduction in susceptibility to MIN and TIG induced by light is likely triggered by the generation of (1)O2, which, by a yet unknown mechanism, would ultimately lead to the activation of resistance genes such as those coding for the efflux pump AdeABC. The clinical relevance of these results may lie in surface-exposed wound infections, given the exposure to light in addition to the relatively low temperatures recorded in this type of lesion. We further show that the modulation of antibiotic susceptibility occurs not only in Acinetobacter baumannii but also in other micro-organisms of clinical relevance such as Escherichia coli and Staphylococcus aureus. Overall, our findings allow us to suggest that MIN and TIG antibiotic treatments may be improved by the inclusion of an iron chelator, in addition to keeping the wounds in the dark, a condition that would increase the effectiveness in the control of infections involving these micro-organisms.
Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, USA.|Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM-CONICET), Facultad de Ciencias Médicas, Universidad de Buenos Aires, Buenos Aires, Argentina.
María Soledad
MS
Ramírez
Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM-CONICET), Facultad de Ciencias Médicas, Universidad de Buenos Aires, Buenos Aires, Argentina.
German Matías
GM
Traglia
Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, 2000 Rosario, Argentina.
Jorgelina Fernanda
JF
Pérez
Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), 2000 Rosario, Argentina.|Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, 2000 Rosario, Argentina.
Gabriela Leticia
GL
Müller
Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), 2000 Rosario, Argentina.
María Florencia
MF
Martínez
Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), 2000 Rosario, Argentina.
Adrián Ezequiel
AE
Golic
Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), 2000 Rosario, Argentina.|Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, 2000 Rosario, Argentina.
María Alejandra
MA
Mussi
D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000528:radiation effects*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects / Q000528:radiation effects; D007501:Iron / Q000378:metabolism; D008027:Light; D026901:Membrane Transport Proteins / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008911:Minocycline / Q000031:analogs & derivatives* / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013211:Staphylococcus aureus / Q000187:drug effects / Q000528:radiation effects; D013696:Temperature; D000078304:Tigecycline
D000900:Anti-Bacterial Agents; D026901:Membrane Transport Proteins; D017382:Reactive Oxygen Species; D000078304:Tigecycline; D007501:Iron; D008911:Minocycline