VOLUME 9, ISSUES

NATIONAL

JOURNAL FALL 1993

IN THIS ISSUEBloodborne pathogens and contagion risks • Lifeguard competitions •

First class swimming pool • Confidence building in scuba •Osteoporosis • Pseudomonas aeruginosa in pools •

COUNCIL FOR NATIONAL COOPERATION IN AQUATICS

ALISON OSINSKI, Ph.D.

AQUATIC CONSULTING SERVICESSAN DIEGO, CA 92109(619) 270-3459(619) 980-5844

PreventingPseudomonas Aeruginosa

Outbreaks in PublicSwimming Pools & Spas

Alison Osinski, Ph.D.Aquatic Consulting Services

3833 Lamont Street, 4C, San Diego, CA 92109June, 1993

Pseudomonas Aeruginosa2

In the past year, pool operators across the country have been reporting

Pseudomonas aeruginosa outbreaks at their facilities, in record numbers.

Pseudomonas aeruginosa is a gram negative bacterium present

in the environment. It is passed into the pool water from the human skin

and gastrointestinal tract, and frequently through broken pool circulation

pipes, or from dirt tracked onto the pool deck. Pseudomonas aeruginosa

is often cultured from warm, moist environments, particularly when

turbulent or aerated, because the bacteria grows rapidly under these

favorable conditions. Because of this fact, many aquatic professionals

mistakenly believe that Pseudomonas is only a problem in warm water

pools and spas. Unfortunately, Pseudomonas can grow in swimming

pool water as well as spa water, on the pool edge and decks, into filter

liners, in the filter sand bed, and inside PVC pipe and water hoses.

If bacteriological analysis of pool water is not performed on a

regular basis, a pool operator will probably be unaware of the

contamination problem until bathers start complaining of infection.

Bathers who spend lengthy amounts of time soaking in a spa, staff

members who wear wet bathing suits throughout their work shift, or

patrons who swim regularly for extended periods of time are most likely

to experience problems.

The most common sign or symptom of a P. aeruginosa infection is a

dermatological problem resulting in a red, bumpy, itchy rash, which looks like

measles. On most bathers, the rash appears on the legs, trunk, inside of the

arms, lower back, neck and shoulders, or anywhere the skin is broken, or where

a swim suit rubs against and irritates the skin.

Pseudomonas Aeruginosa3

Pool associated folliculitis or skin rashes from Pseudomonas

aeruginosa can be prevented by taking a soapy, hot water shower in the

nude, immediately after leaving the pool, and before cooling down and

allowing the pores to close over the bacteria.

According to the Centers for Disease Control, other symptoms

associated with P. aeruginosa infection include: earaches (otitis externa),

breast inflammation (mastitis), feeling ill (malaise), inflammation of the

eye membrane (conjunctivitis), coughing and sore throat caused by

inflammation of the mucous membrane of the pharynx (pharyngitis),

fever, lymph gland inflammation (lymphadenopathy), urinary tract

infections causing impaired ability to pass urine (dysuria), flu-like

symptoms, and nausea.

Although it is not uncommon to find Pseudomonas bacteria present in

pool water, Pseudomonas aeruginosa outbreaks rarely occur in properly

treated and rigorously maintained public aquatic facilities. To prevent the

uncontrolled growth of P. aeruginosa, the following practices are

recommended:

1. Collect water samples from the pools and spas, and take swabs from

inside the filters, on a regular weekly basis for bacteriological water

analysis. Simple tests for Pseudomonas are available, and can be

done by the knowledgeable pool manager. If samples are sent to an

independent laboratory, specifically request that tests for both the

presence, and quantity, of Pseudomonas be performed.

2. Pressure test the pool recirculation systems to make sure there are no

suction side breaks in the lines which may be allowing dirt to enter the

closed systems.

Pseudomonas Aeruginosa4

3. Institute rigorous deck maintenance procedures. The purpose of

cleaning a pool deck is two-fold. Oil, grease, dirt and debris must be

removed through sweeping, rinsing, power washing, and scrubbing

the pool deck with an all-purpose cleaner, detergent, or degreaser

which is compatible with pool water. But more importantly, decks

must be disinfected to prevent bacterial growth, including P.

aeruginosa, and the formation of a slippery biofilm layer. The best,

and least expensive way to disinfect a pool deck, is to spray a 20 to 1

solution of water and sodium hypochlorite on the deck, and rinse with

a high pressure nozzle and hose. For clean-up of blood or bodily

fluids, and to comply with the OSHA regulations for preventing

transmission of bloodborne pathogens, the decks, or any

contaminated surface, should be cleaned with 5.25% sodium

hypochlorite (household bleach) diluted to between 1:10 and 1:100

with water. This is equivalent to disinfecting with a 1:20 solution of

10-12% sodium hypochlorite (liquid pool chlorine). Clean and

disinfect the decks on a nightly, or at least twice weekly basis,

depending on the level of facility use, and, immediately after any

contamination with blood or bodily fluids.. Attempt to keep patrons in

street shoes off the deck, or at least away from the pool edge.

4. Require that infants and young children who are not yet toilet trained

wear tight fitting rubber pants while in the pool.

5. Shock spas daily and pools at least weekly, or as needed if

combined available chlorine levels exceed 0.3 ppm. Make sure that

you allow enough time for the chlorine to reach the breakpoint.

Double check your calculations to make sure the correct amount of

Pseudomonas Aeruginosa5

chlorine is being used. Inject the chlorine into the return lines

using a chemical metering pump, or install a slurry feed bucket so that

large amounts of chemicals can be poured into the return lines. Do

not hand feed or pour the chlorine directly into the pools. Do not

remove high levels of chlorine from the water with sodium thiosulfate.

Let chlorine levels return to normal gradually after the breakpoint has

been achieved.

6. Install an automated pH/ORP controller, or at a minimum, purchase a

portable ORP meter. Maintain a minimum 750 mV oxidation reduction

potential in commercial pools and spas. Oxidation reduction potential

(ORP) is a standard method of a measuring the chlorine's (or bromine,

ozone or other sanitizer-oxidizer's) ability to oxidize and sanitize the

water. ORP sensors measure HOCI conductivity of water, the potential

generated for oxidation, and permit constant monitoring of sanitation

levels. ORP takes into consideration all water constituents, including

oil, grease, IDS, cyanurates, and organic contaminants. It is a true

measure of water cleanliness. ORP falls whenever pH is either high or

low, and when IDS, chloramine or cyanurate levels are high. Organic

and chemical loading drastically reduce the ability of the bactericide to

overcome bacteria. The amount of chlorine needed by weight in parts

per million (ppm) in order to maintain a 750 mv ORP level will vary from

pool to pool depending on other water constituents. 650 millivolts of

ORP is the minimum recommended level for residential pools and

drinking water promulgated by the American Water Works Association

(AWWA). The German DIN Standard recommends a minimum 750 mv

ORP for commercial pools and spas.

Pseudomonas Aeruginosa6

7. Buy fresh chlorine and other pool chemicals from a reputable vendor,

rather than from a mass merchant or local store where the chemicals

may have been sitting in a warehouse or on the shelf for a lengthy

period of time. Store chlorine in a cool, dark, well ventilated location.

Some forms of chlorine have a very short half life and lose their

effectiveness rapidly when exposed to heat or ultraviolet light. If

sodium hypochlorite (liquid chlorine or bleach) is used as the primary

bactericide, purchase a sodium hypochlorite test kit. Sample and test

all sodium hypochlorite deliveries for percentage of available

chlorine. Use sodium hypochlorite on a first in, first out, basis.

8. Don't use defoamers in the spa. Defoamers only change the water

surface tension and hide, rather than correct, the problem.

Defoamers are wetting agents that prevent foaming, or that neutralize

and dissipate suds in aerated spas, fountains and hydrotherapy

pools. Foaming in pools can be caused by: soft water, quaternary

ammonia algaecides, body lotions and suntan oils, tile cleaners, high

IDS levels, air pollution, body fats secreted by the sweat glands,

and oils from the skin. Foaming water is usually an indicator that the

water in the pool or spa needs to be changed. Discontinue use of the

product which causes foaming or drain and refill the pool.

9. Drain and refill the pool and spas when total dissolved solids exceed

1,500 ppm. Dilute the water regularly to control for TDS build-up

which might be interfering with the chlorine's ability to sanitize and

oxidize. If scheduling, or regulations enacted as a result of drought

conditions prohibit the draining and refilling of a pool, consider

Pseudomonas Aeruginosa7

installing a nanofiltration system to purge the water of dissolved

solids.

If high levels of Pseudomonas are found in the pool, the following

procedures should be followed. Rinse pool circulation pipes and equipment

with high levels of chlorine, then drain the pool completely. Remove the sand or

other filter media from the filter tanks, and dispose of the media properly.

Read the material safety data sheets (MSDS) before beginning work.

Make sure that the area in which you are working is extremely well ventilated.

Do not work alone. Both you and your partner should be knowledgeable in first

aid procedures for chemical burns, and respiratory emergencies in case one of

you is overcome by fumes. Don protective clothing that covers all areas of

exposed skin. Wear goggles and a half mask respirator with fresh chlorine

cartridges and particle filters, rubber boots and neoprene gloves.

Scrub the entire surface of the pool, the decks, and the interior of the filter

tank with a solution of 1 part sodium hypochlorite to 20 parts of water. Spray the

chlorine mixture or pour the mixture from the deck down, a small area at a time.

Keep the rinse water on at all times, and rinse frequently with fresh water to cut

down on the fumes. Do not allow the chlorine to collect in the bottom of the

pool, and neutralize the chlorine before pumping it to waste. Refill the pool,

balance the water, and closely monitor the sanitizer levels.

Pseudomonas Aeruginosa8

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Pseudomonas Aeruginosa9

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