No abstract

During a survey for possible rickettsial vectors in villages of the central part of the Thai-Myanmar border from September 2001 to February 2002, four species of fleas were collected from common peridomestic animals. All fleas were tested by PCR to detect DNA of bacteria of the genera Rickettsia (gltA and ompB genes) and Bartonella (ITS and ftsZ genes). Sequencing of PCR-amplified products was done using gltA fragments for Rickettsia and ftsZ fragments for BARTONELLA: Two genotypes related to Rickettsia felis were identified in three Ctenocephalides canis and one C. felis specimen. Further, the following Bartonella spp. were detected: Bartonella henselae in two C. felis specimens; Bartonella clarridgeiae in three C. felis specimens; and a new Bartonella genotype in one Nosopsylla fasciatus specimen. Rickettsia and Bartonella may be frequently detected in fleas infesting peridomestic animals from the western border of Thailand.

Bartonella henselae is the primary agent of cat scratch disease (CSD). In order to study the genetic variation of B. henselae and the correlation of the various genotypes with epidemiological and clinical findings, two seminested, groEL-and pap31-based PCR assays were carried out with specimens from 273 patients. Amplicons were sequenced to determine the genotype of the causative Bartonella species. Compared to our reference intergenic spacer region-based PCR, the groEL-and pap31-based assays were 1.7 and 1.9 times more sensitive, respectively. All 107 positive patients were infected with B. henselae; neither Bartonella clarridgeiae nor other species were detected. Based on the groEL and pap31 sequences, B. henselae amplicons were classified into two genogroups, Marseille and Houston-1, and into four variants, Marseille, CAL-1, Houston-1, and a new variant, ZF-1. Patients infected with either one or the other genogroup did not exhibit different epidemiological or clinical characteristics. Our study highlights the genotypic heterogeneity of B. henselae in patients with CSD.Cat scratch disease (CSD) is most frequently reported in children and young adults, in whom it usually presents as a benign, self-limited lymphadenopathy in lymph nodes draining the site of a cat scratch or bite (13). The first presumed agent of CSD was isolated in 1988 by English and colleagues and was named Afipia felis (11). In 1993, Dolan and colleagues isolated Bartonella henselae from the lymph nodes of patients with CSD for the first time (18). Since then, many data from epidemiological, serological, and molecular biology-based studies (2,7,17) have demonstrated the role of B. henselae rather than A. felis as the main causative agent of CSD. B. henselae exhibits an important heterogeneity; two serotypes, Houston-1 and Marseille, have been described (19), and these correspond to two genotypes based on 16S rRNA sequences, genotypes I and II, respectively (8). To date, the respective pathogenicity spectra of serotypes Marseille and Houston-1 have not been established. In addition, two other Bartonella species, Bartonella quintana and Bartonella clarridgeiae, have been suspected as alternative agents of CSD (4,20,34,38,47,58). Serological analysis by immunofluorescence or enzymelinked immunosorbent assay is a useful tool for the diagnosis of B. henselae infections (5, 15, 46). However, the specificity of serological analysis has been questioned due to the cross-reactivity between B. henselae and other species including B. quintana, Coxiella burnetii (21,36,55), and Chlamydia species (41). Culture has not proved to be very useful for the diagnosis of CSD because of the fastidious nature of Bartonella species (37,42,43). PCR-based detection of Bartonella species coupled with nucleotide sequencing has also been used for the diagnosis of CSD. In our laboratory, we have been using primers derived from gltA (31), rpoB (50), and the 16S-23S intergenic spacer region (ITS) (51) for the detection of Bartonella DNA from human specimens. Unfortunately, ...

Detergent-resistant membranes of eukaryotic cells are enriched in many important cellular signalling molecules and frequently targeted by bacterial pathogens. To learn more about pathogenic mechanisms of Helicobacter pylori and to elucidate novel effects on host epithelial cells, we investigated how bacterial co-cultivation changes the protein composition of detergent-resistant membranes of gastric adenocarcinoma (AGS) tissue culture cells. Using iTRAQ (isobaric tags for relative and absolute quantification) analysis we identified several cellular proteins, which are potentially related to H. pylori virulence. One of the proteins, which showed a significant infection-dependent increase in detergent resistance, was the polarity-associated serine/threonine kinase MARK2 (EMK1/Par-1b). We demonstrate that H. pylori causes the recruitment of MARK2 from the cytosol to the plasma membrane, where it colocalizes with the bacteria and interacts with CagA. Using Mardin Darby Canine Kidney (MDCK) monolayers and a three-dimensional MDCK tissue culture model we showed that association of CagA with MARK2 not only causes disruption of apical junctions, but also inhibition of tubulogenesis and cell differentiation.

The potential role of ticks as vectors of Bartonella species has recently been suggested. In this study, we investigated the presence of Bartonella species in 271 ticks removed from humans in Belluno Province, Italy. By using primers derived from the 60-kDa heat shock protein gene sequences, Bartonella DNA was amplified and sequenced from four Ixodes ricinus ticks (1.48%). To confirm this finding, we performed amplification and partial sequencing of the pap31 protein and the cell division protein FtsZ encoding genes. This process allowed us to definitively identify B. henselae (genotype Houston-1) DNA in the four ticks. Detection of B. henselae in these ticks might represent a highly sensitive form of xenodiagnosis. B. henselae is the first human-infecting Bartonella identified from Ixodes ricinus, a common European tick and the vector of various tickborne pathogens. The role of ticks in the transmission of bartonellosis should be further investigated.