Claudio Valsangiacomo

Eradication of Borrelia burgdorferi infection in primary marginal zone B-cell lymphoma of the skin.

Primary cutaneous B-cell lymphomas have been associated with Borrelia burgdorferi, the spirochete responsible for Lyme disease. Recently, cutaneous marginal zone B-cell lymphoma has been proposed as a distinct clinical-pathological entity. We report a case of primary cutaneous marginal zone lymphoma, associated with B burgdorferi infection. Polymerase chain reaction (PCR) amplification of the third complementarity determining region (CDR3) of the immunoglobulin heavy chain gene showed the presence of a monoclonal lymphoproliferation, therefore strengthening the histological diagnosis of a malignant process. B burgdorfer-specific hbb gene sequences were detected by PCR in the lymphoma tissue at diagnosis but not after antibiotic treatment. A nearly complete clinical and histological regression was observed after B burgdorferi eradication, with immunohistochemistry studies showing disappearance of plasma cell differentiation and a marked decline in the number of CD3+ T cells and Ki-67+ cells. Our case confirms the link between B burgdorferi and some cutaneous lymphomas. The disappearance of the microorganism accompanied by the unequivocal decrease of most indicators of active T- and B-cell immune response strongly supported a pathogenetic role for B burgdorferi in sustaining an antigen-driven development and growth of this cutaneous marginal zone lymphoma. Antibiotic therapy (analogous to Helicobacter pylori infection in gastric MALT lymphoma) might be helpful with the aim of averting or at least deferring the indication for more aggressive treatment.

Identification of two genetic groups in Bacteroides fragilis by multilocus enzyme electrophoresis: distribution of antibiotic resistance (cfiA, cepA) and enterotoxin (bft) encoding genes.

Ninety-three Bacteroides fragilis strains of different origin were analysed by multilocus enzyme electrophoresis (MLEE). Fourteen of the 15 genetic loci analysed were polymorphic, whilst nucleoside phosphorylase was monomorphic. There was a mean of six alleles per locus and a mean genetic diversity of 0.393. Cluster analysis identified 90 electrophoretic types (ETs) separated into two major phylogenetic divisions at a genetic distance of 0.70. Division I consisted of 81 ETs carrying the endogenous class A beta-lactamase gene cepA, whereas division II comprised 9 ETs carrying the class B beta-lactamase gene cfiA, but not cepA. The presence of these two genes was assessed by PCR and the expression of the cfiA gene was investigated by determining the level of resistance to the antibiotic imipenem. MLEE showed a smaller genetic distance among the genotypes of the imipenem-resistant than among the imipenem-susceptible strains. No other particular cluster was observed. The enterotoxin gene (bft) was detected by PCR: DNA sequencing of the products obtained showed that the different bft alleles (bft-1, bft-2 and bft-3) were scattered randomly troughout the phylogenetic tree. No association between distinct clones and clinical manifestations (sepsis, abscesses, diarrhoea), geographical origin or host origin (human or animal) could be found.

Phylogenetic relationships among muscoidea (Diptera: calyptratae) based on mitochondrial DNA sequences.

The utility of a mitochondrial DNA (mtDNA) fragment of about 1100 bp (including partial COI and COII sequences and tRNALeu) for evolutionary studies in Muscoidea is discussed. The species investigated are Scathophaga stercoraria, Microprosopa pallidicauda and Trichopalpus fraterna (family Scathophagidae), Musca domestica (Muscidae), Lasiomma seminitidum (Anthomyiidae) and Fannia armata (Fanniidae). Comparisons were made with published mtDNA sequences of Drosophila, Anopheles and three Calliphoridae species. The molecular phylogeny obtained here matches the classical morphological taxonomy reasonably well. This varies considerably, however, at different taxonomical levels. At a high taxonomic level, there is a clear separation between the Nematocera and the Brachycera, but the Calyptratae–Acalyptratae division is not always supported. At a lower taxonomic level, all species belonging to the same family are well grouped, but at an intermediate level, within the Calyptratae, it is impossible to clearly separate the Muscoidea and Calliphoridae, preventing a firm conclusion on the phylogenetic relationships among Muscoidea families. The entire COI sequence of S. stercoraria, as well as other mtDNA sequences (including the proximal portions of the COI gene, tRNATrp, tRNACys and tRNATyr genes) in Muscoidea species, are also presented and discussed.

Population genetics of Helicobacter pylori in the southern part of Switzerland analysed by sequencing of four housekeeping genes (atpD, glnA, scoB and recA), and by vacA, cagA, iceA and IS605 genotyping

The population biology of 78 Helicobacter pylori strains (71 from Swiss Italian, 4 from East Asian and 3 from South African patients) was investigated by sequence analysis of four housekeeping genes: atpD, scoB, glnA and recA. The vacA genotype, the presence of cagA and IS605, the iceA allelic type, and the resistance to metronidazole, clarithromycin and amoxycillin were determined. A high percentage of DNA polymorphic sites (19.8% for atpD, 21.3% for scoB, 23.7% for glnA and 20.3% for recA) was found. The phylogenetic trees based on the nucleotide sequences of the four gene fragments showed different topologies and were incongruent. The virulence-associated markers were distributed over the dendrograms and no association was found with phylogenetic clusters or clinical manifestations (chronic gastritis, gastric or duodenal ulcer, MALT lymphoma). Moreover, the H ratios (calculated with the homoplasy test) ranged from 0.742 to 0.799, depending on the gene fragment examined. All these observations suggest that H. pylori exists as a recombinant population. The clustering of the strains according to their geographical origin (USA/Europe, East Asia, South Africa) that has recently been demonstrated elsewhere could only be confirmed for the East Asian vacA s1c strains. In contrast, the South African strains clustered together only in the atpD tree. Presumably, recombination at the different loci has masked the evolutionary relationship among the strains.

Tick zoonoses in the southern part of Switzerland (Canton Ticino): occurrence of Borrelia burgdorferi sensu lato and Rickettsia sp.

The diversity and the distribution of tick species and their infection rates by the pathogenic micro-organism Borrelia burgdorferi sensu lato, the etiologic agent of Lyme borreliosis, and Rickettsia sp., were studied in Canton Ticino (the southern part of Switzerland). Ticks specimens collected from animals and humans were classified and analysed for the presence of both pathogens. In particular, PCR analysis was performed for the detection of Borrelia spirochetes in Ixodes ricinus and Ixodes hexagonus, and the hemolymph test was done on Rhipicephalus sanguineus for the detection of Rickettsia sp. PCR assays, performed on 424 of the 989 collected ticks, revealed a low rate of infection (around 2%) of both vectors I. ricinus and I. hexagonus by B. burgdorferi sensu lato. These results are in agreement with the modest number of Lyme borreliosis cases yearly recorded in Ticino. Further, through analysis of DNA sequences, the strains carried by the infected ticks were identified as belonging to the genomic group VS116. The widespread finding of the Mediterranean species Rhipicephalus sanguineus in different locations from July 1994 to October 1995 demonstrates its establishment in Ticino. Of the 210 specimens collected, 70 were analysed and one was infected by Rickettsia sp.

RecA and glnA sequences separate the bacteroides fragilis population into two genetic divisions associated with the antibiotic resistance genotypes cepA and cfiA.

The sequences of part of the glutamine synthetase-encoding gene (glnA) and of the RecA-encoding gene (recA) were determined and aligned for 45 Bacteroides fragilis isolates from different clinical and geographical origin. The patterns of sequence divergence of glnA and recA were very similar. The sequences of a 303-bp fraction of recA showed 45 nucleotide substitutions, 40 of which allowed the separation of B. fragilis into two major divisions, which were not found when the deduced amino acid sequences were considered. The 687-bp sequences analysed for the glnA gene showed 112 nucleotide substitutions, 96 of which separated the population into the same two divisions as those described for recA. In this case, the deduced amino acid sequences showed this subdivision as well: three of the six observed amino acid substitutions were division-specific. Within the two divisions, both genes presented a high degree of sequence conservation. Each B. fragilis division was associated with the presence of a different antibiotic resistance gene: cepA encoding a serine-beta-lactamase (division I) and cfiA encoding a metallo-beta-lactamase (division II). No particular clusters associated with geographical or clinical origin, or with the production of an enterotoxin were observed. Sequencing of the cfiA gene allowed identification of two different alleles in division II. However, no association of these different cfiA alleles with the expression of imipenem resistance was observed. In conclusion, the phylogenetic patterns observed by sequencing recA and glnA are in agreement with those obtained previously by MLEE (multilocus enzyme electrophoresis). Thus, it appears that the evolution of recA and glnA genes is similar to that of the whole chromosome of B. fragilis. Horizontal gene transfer between divisions I and II seems to be low, at best. However, the results of the present study could not clarify definitively whether divisions I and II should be considered as two different B. fragilis genospecies.

First Map of Residential Indoor Radon Measurements in Azerbaijan

This article describes results of the first measurements of indoor radon concentrations in Azerbaijan, including description of the methodology and the mathematical and statistical processing of the results obtained. Measured radon concentrations varied considerably: from almost radon-free houses to around 1100 Bq m-3. However, only ~7% of the total number of measurements exceeded the maximum permissible concentrations. Based on these data, maps of the distribution of volumetric activity and elevated indoor radon concentrations in Azerbaijan were created. These maps reflect a mosaic character of distribution of radon and enhanced values that are confined to seismically active areas at the intersection of an active West Caspian fault with sub-latitudinal faults along the Great and Lesser Caucasus and the Talysh mountains. Spatial correlation of radon and temperature behavior is also described. The data gathered on residential indoor radon have been integrated into the European Indoor Radon Map.