Microbial Identification (DBHT)

The Department for Bioanalysis and Horizon Technologies (DBHT) is formed of the Molecular Identification Service Unit (MISU), the Genomic Services Unit (GSU), Applied and Functional Genomics Unit and Proteomics Unit.

MISU provides a specialist identification service for atypical bacteria, difficult to isolate and emerging pathogens detected in culture negative clinical samples and isolates. Over 1000 species are identified using comparative sequence analysis of 16S ribosomal DNA sequences. Additional specialised tests are required for pathogens that belong to a closely related species that have almost identical 16S ribosomal DNA composition. The Unit provides three tests to identify species within the genus Bacillus and the unit processes anaerobic pathogens which are difficult to isolate from clinical samples and characterise by phenotypic tests in most frontline laboratories.

Specialist identification is based on 16S ribosomal DNA sequence analysis of bacterial isolates and clinical samples which are received from Health Protection Agency, National Health Service, private and commercial laboratories throughout the UK and overseas.  MISU’s role is to receive and process isolates and clinical samples. Biomass for DNA extraction is obtained and target genes are amplified by PCR. PCR products are cleaned up and are submitted for Sanger sequencing or specific pyrosequencing. Identification is achieved by comparing sequence similarity (homology) between the sample PCR product sequence and reference sequences of bacterial species provided by online databases as well as internal DBHT databases, after which a final report is sent to the customer. All clinical samples are archived and all isolates received are sub-cultured and archived. DBHT also has a strong research and development commitment to improve methods of microbial identification and has active programmes in proteomics and mass spectrometry applications.

The Genomic Services Unit provides generic nucleic acid sequencing and fragment sizing services. The unit receives nucleic acids, plasmids, PCR products and bacterial samples (non ACDP3) from customers both within Colindale and across the HPA. Samples are processed based on specific protocols and service type selected by customers from a list in both the user manual and a memorandum of understanding provided to each customer. Sequence and fragment sizing data are checked by Genomic Services against internal standards and quality scores before electronically notifying and reporting the results to allow customers to analyse their own data. In the cases of services requiring customers to submit bacterial cultures for extraction of nucleic acids material prior to sequencing or sizing the service is organised and agreed prior to direct submission of the samples to GSU.

The Department has a strong research and development commitment to improve methods of sequence-based microbial identification and genotyping and has active programmes specialising in Proteomics and mass spectrometry applications in microbial detection and biomarker discovery. Genomic research is organised to address high throughput analysis, resequencing, microarray and other hybridisation and rapid detection approaches. Established approaches are published and shared with reference and specialist laboratories across the HPA through training, workshops and provision of assay and test development and transfer to HPA Laboratories.

For information regarding services and CPA accreditation please refer to our DBHT User Manual (PDF, 254 KB) and CPA certificate of accrediation for DBHT (PDF, 477 KB)