Limited Diversity among Human Isolates of Bartonella henselae

Abstract

A study of 59 isolates of Bartonella henselae reveals relatively limited diversity among those of human origin (n ‫؍‬ 28). Either of two distinct alleles of both gltA and 16S ribosomal DNA (rDNA) was found in all isolates, with a high level of congruity between 16S and gltA inheritance among proven human pathogens. Human isolates from all over Eastern Australia were most commonly 16S rDNA (Bergmans) type I, with the same gltA allele as the type strain (Houston-1). Comparable feline isolates were more commonly 16S type II, with less congruity of inheritance between 16S and gltA alleles. Previously described arbitrarily primed PCR and EagI-HhaI infrequent restriction site PCR fingerprinting techniques separated Bartonella species effectively but lacked discriminating power within B. henselae. Examination of the 16-23S intergenic spacer region revealed for several strains several point mutations as well as a repeat sequence of unknown significance which is readily detected by HaeIII restriction fragment length polymorphism analysis. The bacteriophage-associated papA gene was present in all isolates. Enterobacterial repetitive intergenic consensus PCR proved to be a useful and robust typing tool and clearly separated human isolates (including imported strains) from the majority of feline isolates. Our data are consistent with published evidence and with previous suggestions of intragenomic rearrangements in the type strain and suggest that human isolates come from a limited subset of B. henselae strains. They strengthen arguments for careful exploration of genotype-phenotype relationships and for the development of a multilocus enzyme electrophoresis and multilocus sequence typing-based approach to the phylogeny of B. henselae.

Multispacer Typing To Study the Genotypic Distribution ofBartonella henselaePopulations

“…Such a higher genetic diversity of B. henselae is as yet unexplained, despite the studies conducted on the relationship between cat and human isolates. In Germany and The Netherlands, a majority of human isolates were of 16S rRNA gene type I whereas cat isolates mostly belonged to type II (3,4,10,28,30). In contrast, in Switzerland, France, and the United States, investigators have demonstrated that most of the human isolates of B. henselae belonged to 16S rRNA gene type II (5,8,17).…”

“…This method distinguished seven genotypes among 37 human and cat isolates and suggested that lateral gene transfer occurs among B. henselae isolates (21). Although these investigators and others suggested that human infection is caused by a limited number of specific B. henselae genotypes (4,10,21), the discriminatory power of the genotyping methods that they used and the small number of B. henselae isolates that they studied were insufficient to allow any statistically significant conclusions to be drawn. Therefore, a genotyping tool with greater discriminatory power for genotyping B. henselae at the strain level is needed to investigate the diversity and population structure of this bacterium.…”

“…Such a method would allow investigation of the relationships between cat and human isolates, the question of whether epidemic strains occur in cats, and the geographic heterogeneity of B. henselae isolates. Various methods have been proposed for typing Bartonella isolates (10,12,19,20,26,29,34). Of these, sequence-based methods have the advantages of being applicable to clinical or environmental specimens and producing reproducible and comparable results.…”

Factors associated with the rapid emergence of zoonotic Bartonella infections

“…A recent report of the presence of B. henselae DNA in the teeth of cats buried in France between the XIIIth and XVIth Centuries indicated the presence of mainly genotype Houston I whereas in present times genotype Marseille is highly predominant in cats in that country [142]. It is also interesting to note that some reports [16,68] have emphasized that B. henselae genotype Houston was more commonly identified in human cases of CSD whereas genotype Marseille was predominantly isolated within the respective cat populations.…”

Culture-Negative Endocarditis Due to Houston Complex Bartonella henselae Acquired in Noumea, New Caledonia

“…Bartonella and Q fever serology followed by special staining, PCR techniques, and tissue culture may greatly increase diagnostic yield for culture-negative endocarditis (16), but cross-reactivity occurs between bartonellae, chlamydiae, and the Q fever agent (Coxiella burnetii), another important cause of culture-negative endocarditis (25). In addition, serodiagnosis based on the detection of antibodies to Houston 1 antigens in many countries, including Australia (11), may not reliably detect Marseille-type strains (10), which include proven human pathogens in Oceania (9,19). A recent follow-up study from Israel involving outer membrane preparations of the same strain used in our IFAT (ATCC 49793, a typical Houston-like strain) showed that immunoglobulin Mspecific antibody detection in an enzyme immunoassay was especially highly specific in 98 cases of proven cat scratch disease (31), but the serotype specificity of this assay also remains an open question.…”