Molecular typing of Bartonella henselae DNA extracted from human clinical specimens and cat isolates in Japan

Abstract

Bartonella henselae is the causative agent of cat scratch disease (CSD). To clarify the population structure and relationship between human and cat strains of B. henselae, 55 specimens isolated in Japan, including 24 B. henselae DNA-positive clinical samples from CSD patients and 31 B. henselae isolates from domestic cats, were characterized by multilocus sequence typing (MLST) and the 16S-23S tRNA-Ala/tRNA-Ile intergenic spacer (S1) sequence, which were used previously for strain typing of B. henselae. Three different sequence types (STs) were identified by MLST, one of which was novel. Fifty-two strains (94.5%), including all strains detected in CSD patients, were assigned to ST-1. Eight S1 genotypes were observed, three of which were novel. The 52 ST-1 strains were classified into seven S1 genotypes, two of which were predominant in both human and cat strains. In addition, 5.5% of the strains (3/55) contained two different intergenic spacer S1 copies. These results indicate that the predominant B. henselae MLST ST-1 in Japan is a significantly genetically diverse population on the basis of the sequence diversity of intergenic spacer S1, and that highly prevalent S1 genotypes among cats are often involved in human infections.

Multilocus Sequence Typing of Bartonella henselae in the United Kingdom Indicates that Only a Few, Uncommon Sequence Types Are Associated with Zoonotic Disease

“…However, a further explanation may be that B. henselae strains vary in their ability to provoke disease. This explanation has support from previous studies in which certain genotypes were found to be overrepresented among human-associated strains (1,15,29). However, in all these studies, the validity of the association observed was somewhat compromised by the opportunistic manner in which strains were collected.…”

“…1). Comparison of allelic profiles of STs using eBURST resulted in the three new STs being assigned to one of the three previously described CCs within the species (1,15,20,22,29) (see Fig. S3 in the supplemental material).…”

“…To determine how the population structure of B. henselae in domestic cats (i.e., the natural reservoir) in England fits with that on a wider geographical scale, data from previous MLST studies (1,15,20,22,29) were collated and divided into three categories, i.e., United Kingdom, continental Europe, and the rest of the world (Table 3). The distributions of the common STs in these three categories were not random; ST1 and ST5 were significantly more common in countries outside Europe than in England, and ST5 and ST7 was significantly more common in continental Europe than in England.…”

“…Second, rather than genotype human-associated B. henselae isolates, we applied MLST to extracts of clinical material containing B. henselae DNA. This strategy has previously been applied for the genotyping of human-associated B. henselae strains with multispacer typing (MST), which is an approach similar to MLST (19), and has also been very recently used in conjunction with MLST itself (29).…”

“…Alignment of verified sequences was carried out using MEGA V4.0 (27). Alleles and STs were assigned in accordance with published data (1,15,20,22,29). New allelic combinations were assigned to new STs in their order of detection.…”