Abstract:
The critically ranked carbapenem-resistant Pseudomonas aeruginosa has been observed to infect immunocompromised
patients that consume polluted waters, leading to critical infections and more hospital costs. To save
lives and unburden the public health sectors of preventable costs, non-thermal plasma (NTP) technology was
investigated as an alternative disinfection step that could be applied in wastewater treatment plants (WWTPs) to
inactivate this bacterium and its prominent carbapenem resistance gene (blaNDM-1). Culture and molecular-based
techniques were employed to confirm carbapenem resistance in P. aeruginosa (27853). Culture suspensions of
carbapenem-resistant ATCC P. aeruginosa (16 h culture) were prepared from confirmed isolates and subjected to
plasma treatment at varying time intervals (3 min, 6 min, 9 min, 12 min and 15 min) in triplicates. The plasma
treated samples were evaluated for re-growth and the presence of blaNDM-1. The treatment resulted in a 0.68 log
reduction after 3 min and the highest log reduction of ≥8 after 12 min, suggesting that plasma disinfection has a
great potential to be an efficient tertiary treatment step for WWTPs. Moreover, the gel image showed that band
intensity of blaNDM-1 reduced with treatment time, thereby suggesting a probable reduction of amplified genes.
Notwithstanding, longer treatment time, a grounded electrode with a larger surface (≥ 40 mm diameter) and/or
oxygen-containing feeding gas is warranted to completely inactivate its antibiotic resistance gene (ARG), which
might be bound by biofilms as they seem to protect P. aeruginosa from the action of non-thermal plasma (NTP)
disinfection.
