The pathogens, the first tests and the first samples!


Sample and data collection from a well in Manjacaze, Mozambique.

The aim of our project is to test if DNA techniques can be used in the field to test water quality using a mobile device, making it possible to generate more accurate and reliable data, and faster than the current methods. We are using the mobile Biomeme Two3 device to research this possibility. We decided to test the device in Mozambique by analysing water samples on 5 different pathogens. We thought carefully about which pathogens to test for, because besides testing the device, we aim to generate useful data at the same time. We are very happy to inform you that we made a final decision on the list of pathogens that we are testing for. We focused on bacteria that are pathogenic, waterborne and relevant for Mozambique. Below you will find the list of pathogens and the reason why each pathogen was included in the project.

1) E.coli. This is an indicator for faecal contamination, also it will enable us to compare our results with the traditional culturing techniques.
2) Salmonella spp. They are relevant waterborne pathogens for Mozambique.
3) Shigella spp. They are also waterborne pathogens that are relevant for Mozambique.
4) Pathogenic Leptospira. They are emerging waterborne pathogens, for which E.coli is not an indicator and of which little data is available.
5) Helicobacter pylori. This is also an emerging waterborne pathogen, for which E.coli is not an indicator and of which little data is available.

After deciding on the pathogens, the team was eager to start generating the data and testing the device. We developed the required software for the tests and we have been testing the device in the laboratory of Orvion in The Netherlands. We tested it on known water samples to compare the results of our mobile device with the results of the conventional machine that we use in the lab. The results of these first tests are very promising; it looks like the device can measure the presence of bacteria just as well as the conventional machine! Now we could finally start taking samples in Mozambique. More tests are still needed on the accuracy of the device, but those will now be done on samples from Mozambique. This way we will generate real and useful data while testing the device.

We took samples from a water treatment site of our partner AIAS (the authority responsible for water in secondary cities in Mozambique) in a small town, a 5-hour drive north of Maputo. We worked together with Abtercio, the local chefe of the system, to obtain the samples. We explained wat we were doing and he is looking forward to receiving the results, which will help him identify problem areas in his system. We sampled at 20 different locations to get an idea of the development of the presence of the pathogens. We took 20 samples to send to the Netherlands for testing with our mobile device. To compare our results to the methods currently used for water quality testing, we took an additional 10 samples to send to a lab in Maputo and we analysed 5 samples using the compartment bag test (CBT). In the field it became clear that our water samples were easier to transport. We did not have to worry about the temperature of the samples or the travel time to the lab, because the sample bottles contain a liquid that kills all living organisms in the sample, thus preserving the composition of the water. Since our tests use the DNA in the samples, the organisms we test for do not have to be cultured, or even be alive. The samples for the Mozambican lab had to be delivered to the lab within 24 hours and maintained at the right temperature to get reliable results. Therefore, as soon as the samples were taken, we had to hurry back to Maputo, so we could hand in the samples first thing the next morning. Just in time for the 24-hour limit. If the samples were taken much further from the lab, it would have been difficult to get them to the lab in time. The CBTs had to be kept at the right temperature.
The results of the CBT were available after 24 hours, and showed that three water samples were considered ‘unsafe’, one was ‘Intermediate Risk/ Possibly Safe’ and one sample was ‘low risk/safe’. The results of the Mozambican lab and of our field device are not in yet, but we are very curious to see if they show the same trend. We will tell you about that in our next update!