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.”
- Applied and Environmental Microbiology
Shih, H.-Y. and Lin, Y.E., (2010), Efficacy of Copper-Silver Ionization in Controlling Biofilm- and Plankton-Associated Waterborne Pathogens, Applied and Environmental Biology, Mar; 76(6): 2032-2035
Cultures of bacteria were introduced into a model plumbing system with copper and silver ions present at concentrations between 0.2/0.02 and 0.8/0.08 mg/litre, (i.e. below EPA limits). Samples of both the water and biofilm showed that Pseudomonas aeruginosa were inactivated in both within 72 hours.
- International Water Association
Huang, H.I. et al, (2008), In vitro efficacy of copper and silver ions in eradicating Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Acinetobacter baumannii: Implications for on-site disinfection for hospital infection control, Water Research 42, p. 73-80
The three species of bacteria were exposed to a range of copper ion concentrations (0.1 - 0.8 mg/litre), silver ions (0.01 - 0.08 mg/litre), and combinations of both. All copper solutions achieved more than 99.9990% reduction of P. aeruginosa. Silver at 0.04 - 0.08 mg/litre achieved more than 99.999% reduction. The two together showed a synergistic effect.
- The Journal of Hospital Infection
Fisher, K., Pope, M. & Phillips, C, (2009), Combined effect of copper and silver against Pseudomonas aeruginosa, Journal of Hospital Infection, Vol. 73 (2), p.180-182
Sterile cotton swabs impregnated with copper nitrate and silver nitrate solutions removed 100% of Pseudomonas aeruginosa from a stainless steel surface. There was no cross-contamination of other surfaces when the wipes were applied, suggesting that the microbes has been inactivated.
- Journal of Inorganic Biochemistry
Panzer, M. et al (2013), Isomorphic deactivation of a Pseudomonas aeruginosa oxidoreductase: The crystal structure of Ag(I) metalled azure at 1.7 Å, Journal of Inorganic Biochemistry, 128, P. 11-16
X-ray crystallography showed that the silver ion binds to a key respiratory enzyme in P. aeuginosa, inactivating it.