LABAQUA performs a comparative study between the Bluephage Easy Kit BP1604 and the ISO 10705-2 and 10705-3 methods

The particularity of clean water is that it has a shallow concentration of coliphages, so the sample must be concentrated.

The ISO 10705-3 specifies that the analysis for coliphages in clean water should be done on 100mL of sample and make a concentration, i.e., filter, so that coliphages are retained on the filter, and then resuspend by diluting them in PBS or others.

This additional step can be avoided by using the Bluephage BP1604, as it directly analyses the 100mL of sample, as required by the ISO standard, without concentrating. By avoiding the sample concentration step, the recovery of the analysis increases, and the results are more accurate.

The Easy Kit BP1604 is an all-in-one and ready-to-use kit containing all consumables, except Petridishes, to perform ten analyses plus five positive controls.

The kit comprises ten vials of Ecoli, ten vials of MSB, where the inoculum culture will be prepared, ten vials of 2XMSA, and one vial of calcium chloride used to enhance the contact between the coliphage and the Ecoli.

One of the recent improvements in the kit is the addition of nalidixic acid, a quinolone antibiotic, to kill any flora that may be present in the water, to avoid interfering with the analysis of the calves and the reading when counting coliphages. In addition, all positive control and Ecoli vials come lyophilized in the caps, containing PBS for resuspending with almost no operator or technician handling.

As part of Bluephage’s mission to improve its environmental impact, all bottles in this kit have been renewed from plastic to glass. Thus, the MSB and 2XMSA are in glass bottles, which are recyclable when autoclaved in the lab.

With this new approach, we have also improved the kit shipping arrangement. Currently, the customer receives two separate boxes. One contains biological material, which must be stored immediately in the freezer. The other box contains different materials that can be placed in the refrigerator, but they can also remain at room temperature.

LABAQUA, an experienced, independent, external laboratory accredited to ISO 17025 for multiple microbiological analyses, including coliphages, has recently performed a comparison study of the Bluephage BP1604 kit for drinking water and reclaimed water. The study, signed by IELAB, has been performed between the Bluephage Easy Kit BP1604 and the ISO 10705-2 and 10705-3 methods, which require sample concentration. The report shows that the Bluephage process has superior sample recovery to the ISO standard sample concentration method, and all parameters evaluated show that the method has an acceptable result for reproducibility and uncertainty.  

The report also provides the main benefits of using the BP1604 kit:

After performing the tests described in this study, it can be seen that the main advantage of the Bluephage® BP1604 commercial kit is the time saving, both for the preparation of the necessary material and in the test itself.

• The culture media necessary for somatic coliphage assays by the conventional method (ISO 10705-2) are various, tedious to prepare and with complex quality controls. Host strains also require proper maintenance, prior quantification and verification during the assay. The Bluephage® BP1604 kit includes both the necessary ready-to-use culture media and the lyophilized host cell material that only needs to be incubated for the indicated time prior to its use.
• Since the whole sample (100 mL) is assayed directly with the Bluephage® kit, a prior concentration step is not necessary. This implies a time saving compared to the conventional method (ISO 10705-2). Furthermore, in some cases it can result in higher recovery values by avoiding the concentration phase where phage particles are lost.
• Regarding the reference phage, the management, storage, propagation and controls to verify that the process and results are correct, are laborious and require additional time to the procedure itself. Instead, the Bluephage® BP1604 kit includes the reference phage for the quantified positive control, and it is only necessary to verify that the result obtained is within the acceptance range indicated in the certificate to validate the assay.