Although Pseudomonas seldom infects healthy individuals it's a significant threat to those already suffering from a medical condition, particularly cystic fibrosis, AIDS and cancer. It's also very hard to eliminate.
EnvironmentThere's a lot of evidence linking the hospital water supply to infections in high-risk patients. It's thought that Pseudonomas can be transmitted by drinking, bathing, contact with wounds, splashing from water outlets, inhalation of aerosols, equipment rinsed in contaminated water, etc. Reference
Department of Health, 2013, HTM 04-01 - Addendum: Pseudomonas aeruginosa – advice for augmented care units. Contaminated water in a hospital setting can transmit P. aeuginosa to patients through the following ways:-
- direct contact with the water through:
- – ingesting
- – bathing
- – contact with mucous membranes or surgical site, or
- – through splashing from water outlets or basins (where the flow from the outlet causes splashback from the surface);
- - inhalation of aerosols from respiratory equipment, devices that produce an aerosol or open suctioning of wound irrigations;
- - medical devices/equipment rinsed with contaminated water;
- - indirect contact via healthcare workers’ hands following washing hands in contaminated water, from surfaces contaminated with water or from contaminated equipment such as reusable wash-bowls.”
Mena, K.D. and Gerba, C.P., 2009, Risk Assessment of Pseudomonas aeruginosa in Water, Reviews of Environmental Contamination and Toxicology, 201, 71-115. “Its occurrence in drinking water is probably related more to its ability to colonize biofilms in plumbing fixtures (i.e., faucets, showerheads, etc.) than its presence in the distribution system or treated drinking water.”
Kisko, G. and Szabo-Szabo, O., 2011. Biofilm removal of Pseudomonas strains using hot water sanitation. Acta Univ. Sapientiae Alimentaria, 4, 69-79. "Our results showed that although hot water sanitation reduced the number of Pseudomonas biofilm cells by about 3-log cycles, it left surviving cells, which enable further growth of biofilm. Therefore, it cannot be considered an effective sanitation procedure unless its application is accompanied by further mechanical or chemical sanitation."
Lutz, J.K. & Lee, J., 2011. Prevalence and antimicrobial resistance of Pseudomonas aeruginosa in swimming pools and hot tubs. Int. J. Environ. Res. Public Health, 8, 554-564. "The temperature range in indoor recreational water is ideal for P. aeruginosa proliferation, which routinely grows in water 4-42 degrees Centigrade."
IncidencePseudomonas is more likely to infect those who are already very sick or vulnerable. Patients in critical care units, high dependency units, burns units, transplant units, haematology wards, renal units and oncology wards are especially at risk. Although difficult to estimate, it's believed to be responsible for about 10% of hospital acquired infections, Reference causing:
Gerba, C. & Mena, K.D., (2009). Risk assessment of Pseudomonas aeruginosa in water, Reviews of environmental contamination and toxicology 201: 71-115, Table 5, p.76
- Scepticemia (blood infection)
- Endocarditis (heart infection)
- Osteomyelitis (bone infection)
- Urinary tract infection
- Gastrointestinal disorders
- Pneumonia (70%+ mortality rate)
- Respiratory tract infections
- Meningitis (nervous system)
- Wound infections
Livermore, D.A., 2002, Multiple Mechanisms of Antimicrobial Resistance in Pseudomonas aeruginosa: Our Worst Nightmare?, Clinical Infectious Diseases, 34, 634-64. “Pseudomonas aeruginosa carries multiresistance plasmids less often than does Klebsiella pneumoniae, develops mutational resistance to cephalosporins less readily than Enterobacter species, and has less inherent resistance than Stenotrophomonas maltophilia. What nevertheless makes P. aeruginosa uniquely problematic is a combination of the following: the species' inherent resistance to many drug classes; its ability to acquire resistance, via mutations, to all relevant treatments; its high and increasing rates of resistance locally; and its frequent role in serious infections. A few isolates of P. aeruginosa are resistant to all reliable antibiotics, and this problem seems likely to grow with the emergence of integrins that carry gene cassettes encoding both carbapenemases and amikacin acetyltransferases.”
Scientific Evidence for Copper and Silver efficacy against Pseudomonas bacteria
- Field Studies
- Panzer et al. (2013) studied the isomorphic deactivation of a Pseudomonas aeruginosa oxidoreductase. They showed using X-ray crystallography that the silver ion binds to a key respiratory enzyme in P. aeruginosa, inactivating it. Link to abstract
- Fisher et al. (2009) studied the combined effect of copper and silver against Pseudomonas. Sterile cotton swabs impregnated with copper nitrate and silver nitrate solutions removed 100% of P. aeruginosa from a stainless-steel surface. There was no cross-contamination of other surfaces when the wipes were applied, suggesting that the microbes had been inactivated.
- Huang et al. (2008) studied the in-vitro efficacy of copper and silver ions in eradicating Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Acinetobacter baumanii. The three species of bacteria were exposed to a range of copper ion concentrations (0.1 - 0.8 mg/L), silver ions (0.01 - 0.08 mg/L), and combinations of both. All copper solutions achieved more than 99.99% reduction of P. aeruginosa. Silver at 0.04 - 0.08 mg/L achieved more than 99.99% reduction. The two together showed a synergistic effect. Link to paper
- Yahya et al. (1989) demonstrated complete inactivation of Pseudomonas aeruginosa, and a 2.4 log10 reduction within 2 minutes of Staphylococcus species, by 0.4 mg/L copper, 0.04 mg/L silver, and reduced levels of free chlorine (0.3 mg/L).