A surprising new threat has raised some concerns in the field of public health. Serratia marcescens is a bacterium that is commonly associated with diseases picked up in hospital. It usually infects the lungs, membranes of the brain and can be fatal in certain cases. Carbapenem drugs are the most frequently used to fight this bacterium in the body however there have been studies showing their resistance to many antibiotics including cephamycins, macrolides, and even some penicillins.
In a study done by Nicolas Keck and his colleagues, they found long-lasting persistence of chlorhexidine-resistant S. marcescens. Another occurrence hits close to home as a variant strain, Serratia sp., has been found in a bottle of didecyldimethylammonium chloride (DDAC)-based disinfectant (1%) at the University of Free State. Bacteria have been known to evolve naturally through genetic mutations however the recent COVID-19 pandemic has accelerated the number of times we clean and disinfect our surfaces and our hands, which has increased the rate of their evolution. It is now evident that this may cause even more problems in the future as more microorganisms evolve even faster and become resistant to these chemicals if they are not used properly.
There is minimal quality control on some of the sanitisers provided by companies and if the wrong concentration of ingredients is used, it could lead to disinfectant resistant bacteria. Improper use of disinfectants has led to the persistence of this bacterium in a veterinary clinic in Montpellier, France reports Nicolas Keck and his colleagues. This includes mistakes in the dilution process, inadequate disinfection (duration, contact) and the use of contaminated disinfectants. “If you dilute alcohol-based disinfectants even slightly, they won’t be effective. Also, quite a few hand sanitisers have very low levels of other disinfectants in it. It is like you have a very nice chemical weapon and you are showing them very low concentrations of this, and it is allowing them to build up resistance.” says Professor Robert Bragg, Head of the Veterinary Biotechnology group at the University of the Free State.
Although cases are still rare, bacteria being resistant to both disinfectants and antibiotics poses a great threat, maybe even greater than COVID-19, to our health and may lead to further uncontrollable outbreaks.
https://www.sciencedirect.com/science/article/pii/S0378113520302418?casa_token=1tp1WoKzltEAAAAA:DoC2FSQqGmH2s-51BgjHUO8e9LUTWXKwpcLGhgZoh6nGn0UtWr3_38ZgiOWTufsPbYfcam3Vger3
https://www.sciencedirect.com/science/article/abs/pii/S0924857902001632
https://link.springer.com/article/10.1007/s42770-021-00477-4
https://journals.asm.org/doi/full/10.1128/MRA.00095-20