Typing

About: Typing is a research topic. Over the lifetime, 5010 publications have been published within this topic receiving 146539 citations.

Pyrolysis-mass spectrometry (Py-MS) for the rapid epidemiological typing of clinically significant bacterial pathogens

Abstract: Fresh clinical isolates of Salmonella spp and Streptococcus pyogenes were analysed by pyrolysis-mass spectrometry (Py-MS) The results formed the basis of mathematically derived characterizations of individual strains and these were compared with the results of phage typing for the salmonellas and M protein typing for the streptococci Py-MS was shown to be a rapid and reproducible method for inter-strain comparisons, giving evidence of identity and non-identity between strains that agreed well with the results of conventional tests Py-MS has potential value as a rapid, relatively inexpensive and highly discriminatory method of epidemiological analysis in bacterial disease

Evaluation of New Variable-Number Tandem-Repeat Systems for Typing Mycobacterium tuberculosis with Beijing Genotype Isolates from Beijing, China

Abstract: The newly proposed variable-number tandem-repeat (VNTR) typing system, which includes a basic 15-locus set and a high-resolution 24-locus set (P. Supply et al., J. Clin. Microbiol. 44:4498-4510, 2006), demonstrated a high power for the discrimination of Mycobacterium tuberculosis isolates collected worldwide. To evaluate its ability to differentiate the Beijing genotype strains from the Beijing area in China, 72 isolates with typical Beijing or Beijing-like spacer oligonucleotide typing profiles were subjected to typing with the VNTR system (24 loci) and typing by restriction fragment polymorphism analysis with IS6110 (IS6110-RFLP). Compared to the "old" 12-locus VNTR typing method, use of the 15- and 24-locus systems had a dramatically improved power to discriminate the Beijing genotype strains. A subtle difference in the Hunter-Gaston discriminatory index (HGI) between the 15-locus and the 24-locus systems resulted from only one locus, Mtub29. However, the VNTR-based clusters could be further differentiated by IS6110-RFLP (HGI by IS6110 RFLP, 0.999), although in one case an IS6110 cluster was subdivided by the 15-locus VNTR system. In this sense, use of the newly proposed 15-locus VNTR system along with the Mtub29 locus can serve as a first-line typing method for the epidemiological study of M. tuberculosis isolates in Beijing, while secondary typing of clustered strains by IS6110-RFLP is still required.

Nucleotide sequence-based typing of bacteria and the impact of automation.

Abstract: DNA-based typing methods are increasingly important for the characterisation of bacteria. They are used to monitor the epidemiology of pathogens with public health significance and also to help understand the evolution and population biology of bacteria. However, these methods require accuracy and reproducibility and are often of a high-throughput nature. Laboratory automation is therefore the key to the successful implementation of such methods. This review describes the impact of automation on DNA-based typing methods, particularly multi-locus sequence typing (MLST), and the method components that can be automated.

Long PCR-ribotyping of nontypeable Haemophilus influenzae.

Abstract: PCR-ribotyping, a new typing method based on long PCR, has been developed for nontypeable Haemophilus influenzae (NTHi). Ribosomal operons of NTHi were amplified by long PCR and were found to be highly polymorphic for internal HaeIII sites. The technique was applied to 49 isolates previously subjected to conventional ribotyping, and the two methods showed a high level of concordance for serial isolates from individual subjects. PCR-ribotyping provides a powerful new typing tool for strain characterization in epidemiological investigations of NTHi.