We studied 48 Borreliu isolates that were associated with Lyme borreliosis or were isolated from ticks and identified three DNA relatedness groups by using the S1 nuclease method. The three DNA groups (genospecies) were associated with specific rRNA gene restriction patterns, protein electrophoresis patterns, and patterns of reactivity with murine monoclonal antibodies. Genospecies I corresponded to Borreliu burgdorfen' sensu stricto since it contained the type strain of this species (strain ATCC 35210); this genospecies included 28 isolates from Europe and the United States. Genospecies I1 was named Borrelia garinii sp. nov. and included 13 isolates from Europe and Japan. Genospecies I11 (group VS461) included seven isolates from Europe and Japan.
The organization of the ribosomal genes is unique in Borrelia burgdogeri in that the rrl (23s) and rrf (5s) genes are tandemly duplicated. We took advantage of this uniqueness to assess the restriction polymorphism of PCR products obtained with primers at the 3' end of the first rrfgene and at the 5' end of the second rrl gene. An amplicon that was 226 to 266 bp long was generated from 99 of 100 B. burgdorferi sensu lato strains. The nuclease MseI restriction polymorphism of the amplicons provided a useful tool for identifying B. burgdorferi sensu stricto, Borrelia garinii, Borrelia afielii (formerly group VS461), and Borrelia japonica (formerly group F63B). Furthermore, it allowed us to recognize four new genomic groups, which were confirmed by DNA-DNA hybridization data. Two of these genomic groups comprised European strains, and the other two groups contained American strains. The American genomic groups involved vectors with enzootic cycles quite different from those of B. burgdorferi sensu stricto, which previously was the only Lyme disease Borrelia species known to occur in the United States. Our method could be used for rapid screening of strain collections and for epidemiological and medical purposes.
Ticks are obligate haematophagous acarines that parasitise every class of vertebrate (including man) and have a worldwide distribution. An increasing awareness of tick-borne diseases among clinicians and scientific researchers has led to the recent description of a number of emerging tick-borne bacterial diseases. Since the identification of Borrelia burgdorferi as the agent of Lyme disease in 1982, 11 tick-borne human bacterial pathogens have been described in Europe. Aetiological diagnosis of tick-transmitted diseases is often difficult and relies on specialised laboratories using very specific tools. Interpretation of laboratory data is very important in order to establish the diagnosis. These guidelines aim to help clinicians and microbiologists in diagnosing infection transmitted by tick bites and to provide the scientific and medical community with a better understanding of these infectious diseases.
Borrelia isolates associated with Lyme borreliosis were previously divided into 3 genospecies, B. burgdorferi sensu stricto, B. garinii and group VS461, on the basis of DNA homology. B. burgdorferi sensu stricto and B. garinii were identified by monoclonal antibodies (MAbs), H3TS and D6 respectively, but no MAbs were available to identify group VS461. Two MAbs were produced, I 17.3 and J 8.3 which reacted with OspB and OspA proteins, respectively, of strains belonging to group VS461, which should be named B. afzelii sp. nov. 24 strains were assigned to B. afzelii sp. nov., 11 of them being isolated from skin lesions, 6 from acrodermatitis chronica atrophicans (ACA) and 5 from erythema chronicum migrans (ECM). Although quite unknown in the USA, ACA has frequently been reported in northern Europe where B. afzelii sp. nov. is commonly isolated. This study documents the involvement of B. afzelii sp. nov. as a specific aetiological agent of ACA.
A sensitive assay for Leptospira spp., the causative agent of leptospirosis, was developed on the basis of the polymerase chain reaction (PCR). A 331-bp sequence from the Leptospira interrogans serovar canicola rrs (16S) gene was amplified, and the PCR products were analyzed by DNA-DNA hybridization by using a 289-bp fragment internal to the amplified DNA. Specific PCR products also were obtained with DNA from the closely related nonpathogenic Leptospira biflexa but not with DNA from other spirochetes, such as Borrelia burgdorferi, Borrelia hermsii, Treponema denticola, Treponema paUlidum, Spirochaeta aurantia, or more distant organisms such as Escherichia coli, Staphylococcus aureus, Mycobacterium tuberculosis, and Proteus mirabilis. The assay was able to detect as few as 10 bacteria. Leptospira DNA was detected in urine from experimentally infected mice. In addition, the test was found to be suitable for diagnosing leptospirosis in humans. Cerebrospinal fluid and urine from patients with leptospirosis were positive, whereas samples from control uninfected patients were negative. Genomic DNA-DNA hybridization helped to define nine species (26) of the genus Leptospira, which is composed of more than 200 serovars. The nonpathogenic Leptospira spp.
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