The development of tools for diagnosis of tularemia and typing of Francisella tularensis

Abstract

Rapid development of molecular techniques for the diagnosis of infections and typing of microbes has been seen during the last 10 years. The present review exemplifies this development by presenting the work of the authors and others regarding techniques for the diagnosis of tularemia and typing of Francisella tularensis. The lack of rapid and safe methods for the laboratory diagnosis of tularemia was the rationale behind the development of methods for the direct detection of F. tularensis in clinical specimens. Today, detection by polymerase chain reaction has become an important adjunct to clinical decisions for the early diagnosis of tularemia. The elucidation of the epidemiology and epizootology of the disease has been hampered by the lack of suitable methods. During recent years several DNAbased methods that allow rapid identification of the four F. tularensis subspecies, including differentiation of strains of the two clinically important subspecies, the highly virulent type A strains and less virulent type B strains, have been developed. Since F. tularensis strains of any origin exhibit highly conserved genomic sequences, the availability of extensive genome sequence data was a prerequisite for the development of a typing system that allows discrimination of individual isolates. The most discriminatory method is based on multiple-locus variable-number tandem repeat analysis (MLVA) and uses highly variable parts of the F. tularensis genome. The method will be an important tool in future studies of the molecular epidemiology of tularemia.

Tularemia Associated with Natural Water Sources: Two Case Reports and Review of the Literature

“…In our cases, MAT test was used for diagnosis. Tularemia is known to be one of the causes of granulomatous lymphadenitis [1][2][3]21] , and histopathological findings supported the diagnosis in one of our cases.…”

“…Helvaci et al [13] reported that bacteria were isolated in five seronegative cases. A definite diagnosis of tularemia is established by isolating the agent from body samples such as lymph nodes, wounds, sputum, blood, and pleural fluid [1,3,17,20,21] . However, due to the high virulence and contagiousness of the microorganism, culture is not recommended unless the necessary safety precautions are taken.…”

Rapid comparative genomic analysis for clinical microbiology: The Francisella tularensis paradigm

“…If several typing methods, such as Insertion Sequence Probed RFLP (Thomas et al 2003), macrorestriction using pulsed field gel electrophoresis (PFGE) and amplified fragment length polymorphism (Garcia Del Blanco et al 2002), repetitive element PCR, arbitrarily primed PCR (Johansson et al 2000), and ribotyping (Grif et al 2003) were eventually used for typing F. tularensis subspecies, the results would lack high-resolution discrimination between individual strains. Multilocus sequence typing (MLST) failed to separate F. tularensis strains at the strain level (Johansson et al 2004b). Techniques based on the analysis of variablenumber tandem repeats identified F. tularensis at the strain level and also identified epidemic strains (Farlow et al 2001;Johansson et al 2004a).…”

The role of birds in dissemination ofFrancisella tularensis: first direct molecular evidence for bird-to-human transmission

“…The primer concentration was . The cycling programme was as described by Johansson et al [11]. Three microlitres of the PCR products were mixed with an equal volume of loading buffer (99 .…”