hello rveryone,

colony count on dialysate are reported to be >600 on 4 separate machines, 4 separate test periods from test lab that we are using here.
after using peracidin as our disinfection, aseptic method use to obtain sample from hansen connectors and output of dialyzer.

RO,Loop return, Bircarb mixer colony counts are < 20cfu. LAL on same machines are <0.100eu

R&R hansens,R&R filter, new water lines in/out. tried longer dwell time on percidin disinfection, longer rinse time, waited a day before resampling machines still reported by lab to be >600 colony count!

AT WITS END!!

bringing in separate incubator to verified lab results. what else to do!!

Can you verify that the samples are getting to the lab properly? Is it possible that once they leave your possession they are not being refrigerated properly?

Can you tell me more about your disinfection procedure...frequency, rinse/dwell times/stations/etc. How old are the machines, have they been bug free up until now?

Good points Traveler Tech, just a few more to add. Watchnu, are your machines being disinfected, to include duell, with the rest of the loop? Reasoning, the machines incoming hosing gets disinfected. Your loop LAL is in good order, have you requested an LAL for the machines those also? You may have some bio-film problems. Also, is your bicarbonate culturing within limits, remember, AAMI recommends bicarbonate be cultured at the end of the day (worst case senerio)? When obtaining the dialysate culture/LAL, try a two person policy, this makes it easier to perform an aseptic catch. That is, One person handles the machine prep and the other catches the sample (from the dialysate port of the dialyzer).

I hope this assists you. Please keep us abreast of any findings, thanks.

Hi traveller,
samples are packed with 3 frozen gell paks, foam lined styrofoam containers,fedx next day to lab.

I assumed duties at this facility october 9, 06,
K machines are 3 yrs old.
holding tank, loop, bicarb mixer, machines disinfected with peracidin every thirty days. dwell time is upon positive result at end loop and positive result at machine. rinse of tank/loop begun thereafter.

floor machines per staff, are bleached weekly and heat disinfected daily.?
this is a 30 station unit that was not well maintain before a real technical staff arrived.
rinse/dwell times for machines are standard fresenius times.
looking at past records show inconsistant testing of machines for trend analysis.
my situation begun upon testing the machines and recieving high counts even after disinfection with peracidin

Thank you ATL tech,
The bicarb mixer cultures are within limits. and is tested after third shift (PM).
i have suggested, requested, implemented that all bicarb containers and caps,wands be disinfected daily-bleach.
i will do the 2 person sample collection to see if the count comes down also.
everyones help is appreciated
thanks again

The fact that you mentioned that you inherited a not-so-well maintained water system may imply that you have a biofilm problem. Every time you do a routine disinfect, you are 'peeling' off the outer layer of biofilm and exposing large amounts of bacteria.

Does your unit have a policy for a high-level disinfection using a higher level of disinfectant and increased dwell time in the loop, perhaps overnight(12 hours)? You can use a 10% bleach or 3% renalin/minncare/puristeril solution. Use a minumum of at least 6 hours dwell if possible.

Also, have you cultured your pre-treatment equipment? Post second carbon or post softener may be a problem, or your RO membranes may be overrun or need to be changed. Can you test directly exiting the RO?

watchnu,

We have had an unusual number of elevated colony counts from multiple facilities over the last couple of months also. I have even had chlorinated TAP water samples being reported as >1000 cfu/ml. I know that it is possible to have SOME growth in chlorinated TAP water, when I get this high of a result it really makes me question something at the lab or the supplies, though the lab will never admit to anything.

What lab do you use?

Chuck

Traveller,
my gut feeling is leaning towards the biofilm problem also. that is what so puzzling for me-the RO, holdin tanks,loop and mixer results report back within limits. but since i have been here machines come back HOT.
this unit does not have a HIGH-level disinfect but they are about to have one implemented!
come tuesday i will culture pretreatment just to eliminate or verified problem area.
thank you traveller

Chuck W,
my second impulse was to investigate or find fault in the lab we use-Satellite Lab Services, but 2 get them to admit error is difficult.
I am in Central Pa.
on tuesday when i culture pretreatment equipment i will request analysis of feed water so as to give me direction on tackling this problem.
i have question the supplies also, this really has me shaking my head and wondering what the ....

watchnu,
you may want to pull cultures from the actual incoming hoses. this will help you isolate: loop vs machine.

chuck may have a point about a lab problem, but i would think more than your just your machines would show high growth.

good luck.

have you thought of using an incubator and tsa plates just as a way to verify results.

Before digging real deep into the situation, for a week or two, do the bicarb loop rinse and disinfection yourself, cause then you know that the lines to the boxes are being rinsed properly, and basicly the same with the whole process, then in the middle of this process take your normal amount of Dialysate Cultures, see if there is a difference. The reason im saying this is because i had the same issue kinda, Loop sites were all fine, except for the Dialysate's kept coming back high, Had to many different people doing the loop process, now one person does the loop 6 days a week, works great cause that person is already there 6 days a week. Properly trained the individual, Dialysates have been all at "0" and Lal's <0.5 .

Give it a try if you have the time. Good Luck.

If your End of Loop sample is <20, I doubt that your have biofilm in the RO loop. If you had biofilm, the end of loop sample (or any sample downstream of these 4 machines) would be bad. You may have biofilm in the dialysis machine, hose feeding the machine, or the pipe between the loop and the hose. Take a sample at the end of the hoses feeding these machines and of the dialysate. If the hose is clean and the dialysate is bad, then your problem is somewhere in the machine. You may need to replace the hoses and/or the mixing chamber in the machine to get rid of the problem. Do you have a policy to replace the hose feeding the machine on a periodic basis?

Also, if you have 30+ machines and only these 4 are bad, I doubt that it is a sampling problem unless the same person always samples these machines. Are these 4 machines always connected to the same water port in your loop? If not, this can be another reason that it is not biofilm in the RO loop.

Another suggestion would be to sample the dialysate from these 4 machines with a different hose feeding the machine and a different water station feeding the hose (hose and station from one that has recently been tested to have good results).

Also, you should have a specific dwell time when performing a disinfection...not just when you get a positive result from the end of the loop. For 1% PAA, let is sit for at least 36 minutes (6 log reduction of bacteria) or 11 hours (12 log reduction). For bleach, it depends on what concentration you are using. Let the disinfectant sit in the system with no flow. With no flow, you will be able to expose the surface of the piping to the disinfectant.

I have a question for everyone, if you have a machine with high counts (>200 or endotoxin >2) what do you do with the machine? Do you leave it in service and keep disinfecting it? Do you remove it from service until the results are acceptable? Other?

Florian,
i do a reculture, leaving the machine or station still in use. if repeated positive, it's taken out of use and disinfected and not put back into use until result is negative.

reasoning: usually it's only one machine or station that's positive and everything else is negative, meaning that i'm probably the contamination source.
we don't do reuse or bicarb mixing, all single use.

(good point, i hope watchnu took those out of use)

The policy I wrote stipulates at/above 200 cfu/ml the machine is pulled from service until acceptable results are obtained. Additional chemical with dwell disinfections are performed. All regular daily(heat) and weekly(bleach/heat) disenfections for the previous two weeks of the high culture and all additional disenfections due to the high culture are documented on the lab results sheet(s) and the whole package is brought thru QA to document the actions taken, make sure everyone is informed(again) and to review the procedures in place and discuss if changes are needed