title: Characterization of a tandem repeat polymorphism in Rickettsia strains.
abstract: Mediterranean spotted fever (MSF) is a tick-borne rickettsiosis caused by 'Rickettsia conorii complex' strains. In Portugal, R. conorii and Israeli tick typhus (ITT) are the aetiological agents of this disease. A novel 65 bp tandem repeat was identified by the analysis of the R. conorii Malish 7 whole genome sequence with an appropriate algorithm for searching for repeated sequences. The variable number tandem repeat (VNTR) was named VNTR Rc-65 and this locus was amplified by PCR and sequenced in order to characterize the repeat diversity within different rickettsial strains including Portuguese strains isolated from clinical and vector samples. The VNTR Rc-65 has seven alleles within the rickettsial strains studied and a diversity index value of 0.71, meaning that this locus has a great discriminatory capacity and therefore can be used for identification of closely related strains. PCR amplification of the Rc-65 locus can be used to differentiate between the Portuguese R. conorii Malish-like and Israeli tick typhus strains, enabling a more accurate and rapid identification of these rickettsial isolates.
authors.affiliation: Universidade de Lisboa, Faculdade de Ciências, Centro de Genética e Biologia Molecular and Instituto de Ciência Aplicada e Tecnologia, Edifício ICAT, Campus FCUL, Campo Grande. 1749-016 Lisboa, Portugal 2CEVDI, Instituto Nacional de Saúde Dr Ricardo Jorge, 2965 Águas de Moura, Portugal.
authors.forename: Liliana
authors.initials: L
authors.lastname: Vitorino
authors.affiliation: Universidade de Lisboa, Faculdade de Ciências, Centro de Genética e Biologia Molecular and Instituto de Ciência Aplicada e Tecnologia, Edifício ICAT, Campus FCUL, Campo Grande. 1749-016 Lisboa, Portugal 2CEVDI, Instituto Nacional de Saúde Dr Ricardo Jorge, 2965 Águas de Moura, Portugal.
authors.forename: Rita
authors.initials: R
authors.lastname: de Sousa
authors.affiliation: Universidade de Lisboa, Faculdade de Ciências, Centro de Genética e Biologia Molecular and Instituto de Ciência Aplicada e Tecnologia, Edifício ICAT, Campus FCUL, Campo Grande. 1749-016 Lisboa, Portugal 2CEVDI, Instituto Nacional de Saúde Dr Ricardo Jorge, 2965 Águas de Moura, Portugal.
authors.forename: Fatima
authors.initials: F
authors.lastname: Bacellar
authors.affiliation: Universidade de Lisboa, Faculdade de Ciências, Centro de Genética e Biologia Molecular and Instituto de Ciência Aplicada e Tecnologia, Edifício ICAT, Campus FCUL, Campo Grande. 1749-016 Lisboa, Portugal 2CEVDI, Instituto Nacional de Saúde Dr Ricardo Jorge, 2965 Águas de Moura, Portugal.
authors.forename: Líbia
authors.initials: L
authors.lastname: Zé-Zé
mesh_terms: D000818:Animals; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D006801:Humans; D018598:Minisatellite Repeats / Q000235:genetics*; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D012281:Rickettsia / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D012282:Rickettsia Infections / Q000382:microbiology; D017422:Sequence Analysis, DNA; D013987:Ticks / Q000382:microbiology