Rapid monitoring of bacterial growth and metabolism with the PMEU Unit from clinical, environmental, food and process industry samples

THE PRESENTATION OF PMEU TECHNOLOGY AT THE NEW ZEALAND MICROBIOLOGICAL SOCIETY MEETING 2ND OF DECEMBER 2010, AUCKLAND, WITH THE MOTTO “small things, BIG ideas” BY ADJUNCT PROFESSOR ELIAS HAKALEHTO

ABSTRACT


The idea of constructing a cultivator where microbe enrichment could be started on the sampling site has fascinated us for many years. In the PMEU (Portable Microbe Enrichment Unit) one actually intensifies the research on metabolic reactions in a multiplied scale. This equipment also simulates the interactions between different microbes, and it therefore can be used for studying microbial ecosystems.

Sampling in an Austrian hospital during three years from the bile specimens of about 250 patients indicated that coliformic bacteria and fecal enterococci represented around 60% of the microflora in this part of the gastrointestinal tract. The mixed acid fermenting coliformic strains and the neutral end-products producing Klebsiella/Enterobacter group were shown to live in symbiosis in the PMEU cultures implying to their cooperation in the duodenum. This gives an idea how the microbial community maintains intestinal conditions by regulating the pH and other parameters.

The PMEU Spectrion® equipment validated by the State Research Centre of Finland (VTT) has Ethernet connections which make it possible to follow up the microbe enrichment and detection process in real time. The water department field trials are reported. The PMEU can be used to monitor directly both hygiene indicator strains as well as pathogenic bacteria, both in water and in food. A recent report involving the National Institute of Health and Welfare in Finland describes detection of Campylobacter sp. from natural and household waters using the combination of PMEU enrichment and the real time PCR.

In hospital tests at Kuopio University Hospital in Finland, the PMEU Scentrion® gas sensing bacterial cultivator has been validated for the microbiological blood testing of neonatal and cancer patients. The PMEU has also been used for monitoring the development of the microflora after the birth or antibiosis. The enhanced enrichment could be used effectively for improving the recovery of bacterial cells in the detection process.

Use of portable enrichment unit in rapid characterization of infantile intestinal enterobacterial microbiota

Jouni Pesola‌1,2, Outi Vaarala‌3, Anneli Heitto‌4 & Elias Hakalehto‌4,5
Institute of Clinical Medicine, Pediatrics, University of Kuopio, Kuopio
Department of Pediatrics, Kuopio University Hospital, Kuopio
National Institute for Health and Welfare, Helsinki
Department of Biosciences, University of Kuopio, Kuopio
Finnoflag Oy, Kuopio and Siilinjärvi, Finland
Correspondence: Jouni Pesola, Department of Pediatrics, Kuopio University Hospital, POB 1777, FI-70211 Kuopio, Finland. E-mail: jouni.pesola@kuh.fi

Abstract

Objective: The aim of this study was to develop a practical and efficient method for isolation and characterization of the enterobacterial microbiota of infant fecal samples. It could be used for reliable comparisons between individual microflora in different neonates, and in the follow-up of the succession in the floral developments in various nutritional conditions. Methods: A combination of traditional plate culture and different enrichment procedures carried out in a portable microbe enrichment unit (PMEU) was studied. The strains were isolated by plate culture both before and after enrichment. The isolated strains were identified by biochemical tests and the phenotypes of the isolates were compared by the PhenePlate™ technique. To obtain a picture of the formation of intestinal flora during the first year two follow-up samples were collected at the ages of 3 and 12 months from eight Finnish infants (one girl and seven boys). Results: Altogether 21 and 46 enterobacterial isolates were detected in samples taken at the ages of 3 and 12 months, respectively; 7/21 (33%) and 24/46 (52%) isolates were not detected by direct plating but only after enrichment. This material was supposed to demonstrate the differences between the different methodological approaches. Conclusion: There were age-dependent changes in the species proportions of different subpopulations of Enterobacteriaceae detected from the infantile fecal microbiota at different times. The statistically significant difference in the number of isolations with and without enrichment step suggests that the use of enrichment is highly recommendable and the PMEU equipment and method have now proven suitable for that purpose, at least for screening and monitoring the infant fecal flora. The method offers more representative, quicker, and relatively practical tools for obtaining an overall picture of the enterobacterial microbiota of the fecal samples and its variations, thus also giving an idea of the microbial communities in the gastrointestinal tract.