Typing

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

Utility of multilocus sequence typing as an epidemiological tool for investigation of outbreaks of gastroenteritis caused by Campylobacter jejuni.

Abstract: Multilocus sequence typing (MLST) has been proven useful for the study of the global population structure of Campylobacter jejuni; however, its usefulness for the investigation of outbreaks of disease caused by C. jejuni has not been proven. In this study, MLST plus sequencing of the flaA short variable region (SVR) were applied to 47 isolates from 12 outbreaks of C. jejuni infection whose relatedness has been determined previously, and the results were compared to those of serotyping and pulsed-field gel electrophoresis (PFGE). Isolates implicated in an outbreak were indistinguishable by all four subtyping methods, with sporadic isolates being distinguished from outbreak isolates. Two sporadic isolates from one outbreak were resistant to SmaI digestion and therefore nontypeable by PFGE but were differentiated from the outbreak strain by the other methods. PFGE and flaA SVR typing were the most discriminatory methods, with discriminatory indices (DI) of 0.930 and 0.923, respectively. However, an epidemic strain from one outbreak was distinguished from the other outbreak isolates by flaA SVR typing; its flaA allele was different at five nucleotides, suggesting that this change was possibly mediated by recombination. MLST was less discriminatory than PFGE and flaA SVR typing (DI = 0.859), and many of the epidemic strains possessed common sequence types (STs) including ST-8, -21, -22, and -42. However, further discrimination within STs was achieved by flaA SVR typing or PFGE. The results from this study demonstrate that a combined approach of MLST plus flaA SVR typing provides a level of discrimination equivalent to PFGE for outbreak investigations.

Chapter VIII Serological Typing Methods of Leptospires

Abstract: Publisher Summary This chapter discusses the serological typing methods of Leptospires . They are the members of the Treponemataceae family. The genus includes strains which are parasitic or free living. Some strains may be pathogenic for man or various other animal species. When leptospira strains are classified, first the serogroup to which a strain belongs has to be determined by the microscopic agglutination test using selected rabbit group sera. The procedures used for the determination of the serotype status of a strain are derived from the definition of serotypes. Serotypes should be subdivided into varieties based on the presence of a thermolabile antigen. The relatively high specificity of host-serotype relationships means that accurate typing of isolated strains is one of the basic methods for epidemiological investigations. In studies dealing with pathogenic properties of strains-production of hemolysis, and lipases, knowledge of the serotype status is also essential.