Test for bacterial resistance build-up against plasma treatment

Abstract

It is well known that the evolution of resistance of microorganisms to a range of different antibiotics presents a major problem in the control of infectious diseases. Accordingly, new bactericidal 'agents' are in great demand. Using a cold atmospheric pressure (CAP) plasma dispenser operated with ambient air, a more than five orders of magnitude inactivation or reduction of Methicillin-resistant Staphylococcus aureus (MRSA; resistant against a large number of the tested antibiotics) was obtained in less than 10 s. This makes CAP the most promising candidate for combating nosocomial (hospital-induced) infections. To test for the occurrence and development of bacterial resistance against such plasmas, experiments with Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Enterococcus mundtii) were performed. The aim was to determine quantitative limits for primary (naturally) or secondary (acquired) resistance against the plasma treatment. Our results show that E. coli and E. mundtii possess no primary resistance against the plasma treatment. By generating four generations of bacteria for every strain, where the survivors of the plasma treatment were used for the production of the next generation, a lower limit to secondary resistance was obtained. Our results indicate that 4 2 CAP technology could contribute to the control of infections in hospitals, in outpatient care and in disaster situations, providing a new, fast and efficient broad-band disinfection technology that is not constrained by bacterial resistance mechanisms.

Inhibition of methicillin resistant Staphylococcus aureus by a plasma needle

“…Higher plasma powers (0.9 W, 1.6 W) significantly decreased biofilm production by 10 4 MRSA cells regardless of the exposure time ( Fig. 2A), while a decrease in biofilm production by 10 5 MRSA cells required a longer exposure, i.e. 60 and 120 s (Fig.…”

“…Most studies have shown very good results [5][6][7][8] in direct contact of plasmas with microorganisms. However sterilization of planktonic samples and biofilms proved to be more difficult [9][10][11][12][13]. In this paper we extend the application of a plasma needle that has been tested in direct contact with plant and mammalian cells [14,15] and for planktonic samples of bacteria [15] to study sterilization of biofilms.…”

Terminal sterilization: Conventional methods versus emerging cold atmospheric pressure plasma technology for non‐viable biological tissues

“…[81] It has been postulated that the accumulation of plasma charged particles over the bacterial cell membrane causes membrane rupture through electrostatic disruption [105] ; or that the reactive species permeabilize and penetrate the cell walls before reacting with DNA via complex mechanisms. [106] Membrane damage through lipid peroxidation is another major cause of bacterial death by CAP. The effect by heat and UV is argued to be indirect or negligible.…”

“…[82] Microorganism resistance to CAP is unlikely to occur. [106] Inexpensive. [202] Can be used portably or in smaller scale (such as in laminar flow hoods and isolators).…”

Emerging applications of low temperature gas plasmas in the food industry

“…In contrast to chemical-based technologies, plasmas can be created in environmentally friendly gases, including air, thus minimizing the environmental burden of the technology, and given their broad range of antimicrobial agents it makes it difficult for bacteria to develop resistance. 40 Many of the pioneering studies reported in the literature have used plasma sources initially conceived for other applications (e.g. semiconductor processing).…”