195
Methods of analysis
Thewater systems that can be sources of the dissemination of
Legionella
may
bemonitored by laboratorymethods.Themost usual is the one described on the
French standard - ISO 11731-2 –Water quality – Detection and Enumeration of
Legionella
,but thereareothertechniques thatareabletoisolatethemicroorganism
more precisely than the traditional method referred to above. It will all depend
on the type of system in which it will be sampled, as for example, in places where
there is no sufficient water for analysis or there is only biofilm, it is indicated
to proceed to the sampling by using the Swab method. Another method that
was developed recently by a North-American company is the PVT method
(Phigenics Validation Test). This new technique is very promising and it came
to revolutionize the market in terms of the search on
Legionella
.Throughout this
chapter we will be addressing more about this method.
A major problem concerning the analysis of
Legionella
is related to the
transportation of samples of water, because of the unpredicted changes that
the sample may suffer if shipped or stored incorrectly, for this can reduce
the precision of the results; such lack of precision can be eliminated by
initiating the culture at the place and at the “zero time”, i.e., immediately after
collecting the sample from the water system of the building. In addition,
the rapid response enables that actions are taken sooner as possible. Also,
with the results in hand the customer can establish the correct measures for
the treatment of the contaminated water.
When thinking about these transportation problems, the North-
American company developed a new technique, the PVT method, a new
methodology for detection of the bacteria with the approval of the CDC
(Centers for Disease Control and Prevention), allowing the tests to be more
exact and with faster results.
