Pseudomonas bacteria are proving to be formidable opponents in industrial cooling towers, rapidly developing resistance to glutaraldehyde biocides that were once highly effective.
Here’s what’s happening:
The Challenge: Pseudomonas species possess remarkable genetic plasticity, allowing them to quickly adapt to biocide stress. Within just weeks of glutaraldehyde treatment, populations can develop resistance through multiple mechanisms – from enhanced efflux pumps that actively remove the biocide to modified cell wall permeability that reduces uptake. Perhaps most concerning is their ability to upregulate aldehyde dehydrogenases, enzymes that directly metabolize and neutralize glutaraldehyde before it can cross-link cellular proteins.
Why This Matters: Resistant biofilms don’t just survive treatment – they thrive and create “protective zones” for other microorganisms. When Pseudomonas detoxifies glutaraldehyde, it creates localized areas where the biocide is neutralized, allowing normally susceptible bacteria, fungi, and algae to flourish under this “umbrella of protection.” This leads to:
- Rapid recolonization by diverse microbial communities
- Reduced heat transfer efficiency
- Increased corrosion rates
- Higher operational costs
- Potential health risks (especially P. aeruginosa)
The Evolution in Action: These bacteria can share resistance genes horizontally, meaning one resistant strain can rapidly spread its survival toolkit to the entire microbial community. It’s evolution on fast-forward.
Moving Forward: The industry is shifting toward rotation strategies, combination treatments, and novel biocide chemistries. Understanding microbial ecology isn’t just academic anymore – it’s essential for system reliability.
For water treatment professionals: Are you seeing similar resistance patterns in your systems? The days of “one-size-fits-all” biocide programs may be behind us.
If you think your biocides are losing their effectiveness, Aster Bio can help you identify the bacteria that may be the source of the problem.