Molecular diagnostics of medically important bacterial infections.

Northern Ireland Public Health Laboratory, Department of Bacteriology, Belfast City Hospital, Belfast, Northern Ireland, BT9 7AD, UK.
Current issues in molecular biology (Impact Factor: 6). 02/2007; 9(1):21-39.
Source: PubMed

ABSTRACT Infectious diseases are common diseases all over the world. A recent World Health Organization report indicated that infectious diseases are now the world's biggest killer of children and young adults. Infectious diseases in non-industrialized countries caused 45% in all and 63% of death in early childhood. In developed countries, the emergence of new, rare or already-forgotten infectious diseases, such as HIV/AIDS, Lyme disease and tuberculosis, has stimulated public interest and inspired commitments to surveillance and control. Recently, it is reported that infectious diseases are responsible for more than 17 million deaths worldwide each year, most of which are associated with bacterial infections. Hence, the control of infectious diseases control is still an important task in the world. The ability to control such bacterial infections is largely dependent on the ability to detect these aetiological agents in the clinical microbiology laboratory. Diagnostic medical bacteriology consists of two main components namely identification and typing. Molecular biology has the potential to revolutionise the way in which diagnostic tests are delivered in order to optimise care of the infected patient, whether they occur in hospital or in the community. Since the discovery of PCR in the late 1980s, there has been an enormous amount of research performed which has enabled the introduction of molecular tests to several areas of routine clinical microbiology. Molecular biology techniques continue to evolve rapidly, so it has been problematic for many laboratories to decide upon which test to introduce before that technology becomes outdated. However the vast majority of diagnostic clinical bacteriology laboratories do not currently employ any form of molecular diagnostics but the use such technology is becoming more widespread in both specialized regional laboratories as well as in national reference laboratories. Presently molecular biology offers a wide repertoire of techniques and permutations of these analytical tools, hence this article wishes to explore the application of these in the diagnostic laboratory setting.

  • Source
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present study describes the development and evaluation of a duplex polymerase chain reaction (D-PCR) for diagnosis and simultaneous identification of tuberculous meningitis (TBM) and bacterial meningitis (BM) in a single reaction. A D-PCR with primers amplifying portions of the Mycobacterium tuberculosis IS6110 and the eubacteria 16SrDNA sequence in a same reaction mix was developed and tested on DNA extracted from 150 clinical CSF samples from different categories (TBM = 39, BM = 26, control infectious and non-infectious category = 85). The results indicate a clear differentiation between bands for eubacteria and M. tuberculosis with an analytical sensitivity of 103 cfu/ml for eubacteria and 102 cfu/ml for M. tuberculosis. When evaluated in clinical samples, D-PCR overall diagnosed 100 % confirmed TBM and 100 % confirmed BM cases with overall specificity of 96.5 %. D-PCR can be an effective tool for diagnosis and simultaneous identification of TBM or BM in a single PCR reaction. It saves time, cost, labour and sample amount and help in administration of appropriate antimicrobial therapy. The proposed diagnostic assay would be helpful in correct and rapid management of TBM and BM patients.
    Indian Journal of Microbiology 06/2015; 55(2). DOI:10.1007/s12088-015-0517-9 · 0.83 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Treatment of community acquired pneumonia (CAP) patients with antibiotics before laboratory-confirmed diagnosis leads to loss of knowledge on the causative bacterial pathogen. Therefore, an increasing number of pneumococcal infections is identified using non-culture based techniques. However, methods for serotyping directly on the clinical specimen remain scarce. Here we present three approaches for detection and serotyping of pneumococci using samples from patients with CAP. The first approach is quantitative PCR (qPCR) analysis on blood samples (n = 211) followed by capsular sequence typing (CST) to identify the serotype. The second approach, a urinary antigen assay (n = 223), designated as inhibition multiplex immunoassay (IMIA), is based on Luminex technology targeting 14 serotypes. The third approach is a multiplex immunoassay (MIA) (n = 171) also based on Luminex technology which detects serologic antibody responses against 14 serotypes. The three alternative assays were performed on samples obtained from 309 adult hospitalized CAP patients in 2007-2010 and the results were compared with those obtained from conventional laboratory methods to detect pneumococcal CAP, i.e. blood cultures, sputum cultures and BinaxNOW® urinary antigen tests. Using qPCR, MIA and IMIA, we were able to detect the pneumococcus in samples of 56% more patients compared to conventional methods. Furthermore, we were able to assign a serotype to the infecting pneumococcus from samples of 25% of all CAP patients, using any of the three serotyping methods (CST, IMIA and MIA). This study indicates the usefulness of additional molecular methods to conventional laboratory methods for the detection of pneumococcal pneumonia. Direct detection and subsequent serotyping on clinical samples will improve the accuracy of pneumococcal surveillance to monitor vaccine effectiveness.
    BMC Infectious Diseases 02/2015; 15(1). DOI:10.1186/s12879-015-0788-0 · 2.56 Impact Factor

Full-text (2 Sources)

Available from
May 31, 2014