Pseudomonas Bacteria Are Common Organisms That Can Thrive in Water Systems

8/2/2019 Pseudomonas Bacteria Are Common Organisms That Can Thrive in Water Systems

1/4

Summary Regarding Description and Control

Measures for Pseudomonas in Drinking WaterPseudomonas bacteria are common organisms that can thrive in water systems. There are many different types of

these bacteria, however some are deemed much more serious than others when it comes to water quality.

What problems does it cause?

Once in a water system, pseudomonas bacteria grow rapidly, quickly forming a bio-film on pipework if left

untreated. Biofilms are a critical area in water systems, where other bacteria, such as legionella can inhabit.

Pseudomonas bacteria are extremely difficult to eradicate once they have formed within a system and are therefore

ideally tackled pro-actively before the problem occurs.

The bio-films caused by pseudomonas, adversely affect drinking water; impairing the taste, appearance and safetyof the water.

Pseudomonas aeruginosa is a more serious variety of this organism, which can cause illness if allowed to form in

water systems. Pseudomonas should therefore not be present in the water systems of places that have regular human

contact, such as hospitals and swimming pools.

Where is it found?

Pseudomonas colonises in water systems if allowed to enter the system. It grows more when it has access to a higher

level of oxygen and the temperature is between 20 40 C, although it can grow outside of this range with a pH

value of 7 8.5.

What can be done?

A number of actions that can be taken to prevent pseudomonas contaminations, ranging from simple procedures to

reduce the likelihood of the bacteria even occurring in your system, whilst others are actual water treatments toeliminate the organisms, once in systems. The extent of the problem and the type of system involved, will determine

the best treatment for each application, these should be discussed with your Hydrotec representative.

For domestic water systems, treatment approaches again includeUV and Chlorine Dioxide systems.

Introduction

Over recent years, various factors have created an increase in the demand for water disinfection.

In todays more energy-conscious world, there has been a move towards operating hot water

systems at lower temperatures. This is clearly a positive step but has needed to be countered by anincrease in effective water treatment.

In addition, recycled water is being used more often for ecological reasons, also heightening theneed to eliminate micro-organisms such as bacteria, spores, moulds and viruses.

These factors, along with a growing awareness of the dangers presented by certain bacteria andstringent health and safety legislation, have resulted in this upturn in demand.
http://www.hydrotec.co.uk/LinkClick.aspx?link=64&tabid=151&language=en-GBhttp://www.hydrotec.co.uk/LinkClick.aspx?link=64&tabid=151&language=en-GBhttp://www.hydrotec.co.uk/LinkClick.aspx?link=63&tabid=151&language=en-GBhttp://www.hydrotec.co.uk/LinkClick.aspx?link=63&tabid=151&language=en-GBhttp://www.hydrotec.co.uk/LinkClick.aspx?link=64&tabid=151&language=en-GB


2/4

Making light work of your problems

So what is the best way to ensure that your water system remains free from bacteria and othermicro-organisms? The dangers associated with bacteria such as legionella and pseudomonas,mean that it is highly advisable to have a pro-active solution in place.

Installing ultraviolet water disinfection equipment, such as the Hydropur, kills almost all bacteriaand micro-organisms passing through the unit and thus preventing them from becoming an issue.

What will Ultraviolet Water Disinfection achieve?

Unlike other methods of disinfection, such as chlorine, there are no negative side-effects to theHydropur; your water is left chemical-free and does not become tainted with an unpleasant smell ortaste.

Clearly, with minimal requirement for maintenance and a highly effective killing rate, Hydropur is theideal solution for preventing contamination in the vast majority of cases.

Hydropur systems can be installed as a gate keeper to treat any bacteria that may try to enter thefacility via the mains water system, or it can be used as a point of use treatment, where, forexample, legionella may need to be controlled.

So how does it work?

Sunlight consists of UV, UV-A, UV-B and UV-C. Whilst these all have germicidal properties, it is theUV-C (or short-wave ultraviolet) that has the most germicidal potential.

As UV-C is filtered out by the earths atmosphere, it is rarely found on earth but can be re-created byusing an ultra-violet lamp.

The UV light penetrates the cell wall of a micro-organism such as bacteria, a virus or fungi. In doingso it alters the micro-organisms DNA, which in turn prevents it from reproducing, therebypreventing the bacteria, virus or fungi from proliferating within the system.

Introduction

Across industry generally there is an increasing requirement for safe, effective and economical disinfection of

water.

This has been brought about by the growing awareness of the dangers and problems caused by the presence of

bacteria in water supplies, together with more stringent health and safety legislation relating to water quality.

What will chlorine dioxide dosing by the Hydrodos achieve?

While legionella and pseudomonas are the key waterborne bacteria to be addressed within building services

applications, there are many other micro-organisms that have to be taken into account. Chlorine dioxide is a

highly effective method of dealing with a large and diverse range of organisms including the following bacteria:

Algae and Amoebae

Coliforms

Cryptosporidium

Giardia Cysts


3/4

Legionella Pneumophila

Listeria

Pseudomonas

Salmonella

Applications

Potable water disinfection

Legionella-control method for hot and cold domestic water systems, approved by the Health and Safety

Executive, when used in accordance with the L8 Approved Code of Practice

Control and removal of biofilms

Water recycling projects

Microbiological control for open evaporative cooling systems

Food and beverage applications

Many others

So how does it work?

Two chemical precursors (Hydrodos SC and Hydrodos HA) are simultaneously pumped (via high-qualitydigital metering pumps) to a holding zone within the main Hydrodos unit. Here the reaction between the

precursors is controlled and designed to provide a high yield of the chlorine dioxide disinfectant required. In

doing so, the quantity of undesirable by-products, is minimised such as chlorites that otherwise would enter the

water system.

The Hydrodos system is imitated by a water meter installed in the main water supply line that feeds the

building, storage tank or process, (see the technical sections for greater detail of dosing regime). On-board

system analysers check the dosing level and provide an additional control loop for system safety and integrity,

whilst also providing information to both a local display and outputs to a BMS system if so desired.

Significance in drinking-water and Control Measures:

Although P. aeruginosa can be signifi cant in certain settings such as health-care facilities, there is no

evidence that normal uses of drinking-water supplies are a source of infection in the general population.

However, the presence of high numbers of P. aeruginosa in potable water, notably in packaged water,

can be associated with complaints about taste, odour and turbidity. Pseudomonas aeruginosa is sensitive

to disinfection, and entry into distribution systems can be minimized by adequate dis-infection. Control

measures that are designed to minimize biofi lm growth, includ-ing treatment to optimize organic carbon

removal, restriction of the residence time of water in distribution systems and maintenance of

disinfectant residuals, should reduce the growth of these organisms. Pseudomonas aeruginosa is detected

by HPC, which can be used together with parameters such as disinfectant residuals to indicate conditions

that could support growth of these organisms. However, as P. aeruginosa is a common environmental

organism, E. coli (or, alternatively, thermotolerant coli-forms) cannot be used for this purpose.

Control of biofilm formation in water using

molecularly capped silver Nano-particles


4/4

Control of biofouling and its negative effects on process performance of water systems is a serious

operational challenge in all of the water sectors. Molecularly capped silver nanoparticles (Ag-MCNPs)

were used as a pretreatment strategy for controlling biofilm development in aqueous suspensions using

the model organism Pseudomonas aeruginosa. Biofilm control was tested in a two-step procedure:

planktonic P. aeruginosa was exposed to the Ag-MCNPs and then the adherent biofilm formed by the

surviving cells was monitored by applying a model biofilm-formation assay. Under specific conditions,Ag-MCNPs retarded biofilm formation, even when high percentage of planktonic P. aeruginosa cells

survived the treatment. For example, Ag-MCNPs (10 mgmL1) retarded biofilm formation (>60%), when

50 percent of the planktonic P. aeruginosa cells survived the treatment.

Moreover, stable low value of relative biomass has been formed in the presence of fixed Ag-MCNPs

concentrations at various biofilm incubation times. Our results showed that Ag-MCNPs pretreated cells

were able to produce EPS although they succeeded to form rela-tively low adherent biofilm.

Use of newly isolated phages for control of Pseudomonas

aeruginosPseudomonas aeruginosa is a relevant opportunistic pathogen involved in nosocomial infections that

frequently shows low antibiotic susceptibility. One of its virulence factors is associated with the ability to

adhere to surfaces and form virulent biofilms. This work describes the isolation and characterization of

lytic phages capable of infecting antibiotic-resistant P. aeruginosa strains. In addition, characterization of

P. aeruginosa biofilms and the potential of newly isolated phages for planktonic and biofilm control was

accessed. According to the results, the isolated phages showed different spectra of activity and efficiency

of lysis. Four broad lytic phages were selected for infection of planktonic cells; however, despite their

broad range of activity, two of the selected phages failed to efficiently control planktonic cultures.

Therefore, only two phages (phiIBB-PAA2 and phiIBB-PAP21), highly capable of causing strong

biomass reduction of planktonic cells, were tested against 24 h biofilms using a m.o.i. of 1. Both phages

reduced approximately 1e 2 log the biofilm population after 2 h of infection and reduction was further

enhanced after 6 h of biofilm infection. However, biofilm cells of P. aeruginosa PAO1 acquired resistance

to phiIBB-PAP21; consequently, an increase in the number of cells after 24 h of treatment was observed.

Conversely, phage phiIB-PAA2 for P. aeruginosa ATCC10145 continued to destroy biofilm cells, even

after 24 h of infection. In these biofilms, phages caused a 3 log reduction in the number of viable counts

of biofilm cells.

Documents

Pseudomonas Bacteria Are Common Organisms That Can Thrive in Water Systems