Bartonella apis sp. nov., a honey bee gut symbiont of the class Alphaproteobacteria.

Here, we report the culture and characterization of an alphaproteobacterium of the order Rhizobiales, isolated from the gut of the honey bee Apis mellifera. Strain PEB0122T shares >95 % 16S rRNA gene sequence similarity with species of the genus Bartonella, a group of mammalian pathogens transmitted by bloodsucking arthropods. Phylogenetic analyses showed that PEB0122T and related strains from the honey bee gut form a sister clade of the genus Bartonella. Optimal growth of strain PEB0122T was obtained on solid media supplemented with defibrinated sheep blood under microaerophilic conditions at 35-37 °C, which is consistent with the cultural characteristics of other species of the genus Bartonella. Reduced growth of strain PEB0122T also occurred under aerobic conditions. The rod-shaped cells of strain PEB0122T had a mean length of 1.2-1.8 μm and revealed hairy surface structures. Strain PEB0122T was positive for catalase, cytochrome c oxidase, urease and nitrate reductase. The fatty acid composition was comparable to those of other species of the genus Bartonella, with palmitic acid (C16 : 0) and isomers of 18- and 19-carbon chains being the most abundant. The genomic DNA G+C content of PEB0122T was determined to be about 45.5 mol%. The high 16S rRNA gene sequence similarity with species of Bartonella and its close phylogenetic position suggest that strain PEB0122T represents a novel species within the genus Bartonella, for which we propose the name Bartonella apis sp. nov. The type strain is PEB0122T ( = NCIMB 14961T = DSM 29779T).

Maladie des griffes du chat et autres bartonelloses [Cat scratch disease and other human infections caused by Bartonella species].

The different Bartonella species can cause various human infections such as cat scratch disease, chronic bacteremia (homeless patient with nonspecific symptom), endocarditis, bacillary angiomatosis, peliosis, and Carrion's disease. Diagnostic approaches include serology, culture and molecular approaches. PCR is especially useful on lymph nodes biopsies from patients with cat-scratch disease and on valvular samples taken from culture-negative endocarditis. Serology exhibits a very high sensitivity in the latter situation. The treatment should be chosen according to the clinical presentation.

Severe occlusive vasculitis as a complication of cat scratch disease

BACKGROUND: The purpose of this communication is to report a severe occlusive vasculitis as a complication of cat scratch. HISTORY AND SIGNS: A 34-year-old Hispanic woman presented with a sudden visual loss of the right eye associated with shivers, high fever and arthritis which developed 2 months after a cat's bite. Fundus examination showed papillitis and a palor of the paramacular zone of the retina. Fluorescein angiography revealed multiple arterial and venous vasculitic occlusions. THERAPY AND OUTCOME: Auto-immune disease and endocarditis were ruled out by an extensive medical work-up.The diagnosis of Bartonella henselae was confirmed by a positive serology. A systemic antibiotherapy with azithromycin, doxycyclin, rifampicin and steroid therapy resulted in a good clinical response, including a rapid visual recovery with a visual acuity of 20/20 and no relapse of the disease at 6 months follow-up. CONCLUSIONS: Ocular complications associated with cat scratch disease may include vasculitis with both arterial and venous occlusions causing severe visual loss.

ESCMID postgraduate technical workshop on intracellular bacteria: from biology to clinic.

Infection by intracellular bacteria can lead to several diseases in both veterinary and human medicine. Unfortunately, the biology of these intracellular bacteria is highly complex due to their interactions with their host cells. Thus, it is very important to develop several tools in order to better understand the complex intracellular life of these pathogens, so allowing to improve the diagnosis options and the treatments of infectious diseases that they are causing. The workshop organised in Villars-sur-Ollon (Switzerland) by the ESCMID Study group on intracellular bacteria was a good opportunity to enhance our knowledge on these fastidious pathogens. During 5 days, 15 speakers gave 41 talks, covering all fields, from biology to clinic of different intracellular bacteria such as Bartonella, Chlamydia, Coxiella, Ehrlichia, Listeria, Parachlamydia, Rickettsia, and Waddlia. The format of this postgraduate course, which took place in the Swiss mountains, allowed interactive sessions and living discussions between the participants coming from all around the world. One of the major strength was to gather epidemiologists, clinical microbiologists, infectious diseases specialists, entomologists, veterinarians as well as bioinformaticians, biochemists and biologists to deliver a unique "one-health science" on intracellular bacteria. Here, we summarise the main take-home messages delivered during this meeting.

Infective endocarditis.

Despite improvements in health care, the incidence of infective endocarditis has not decreased over the past decades. This apparent paradox is explained by a progressive evolution in risk factors; while classic predisposing conditions such as rheumatic heart disease have been all but eradicated, new risk factors for infective endocarditis have emerged. These include intravenous drug use, sclerotic valve disease in elderly patients, use of prosthetic valves, and nosocomial disease. Newly identified pathogens, which are difficult to cultivate--eg, Bartonella spp and Tropheryma whipplei--are present in selected individuals, and resistant organisms are challenging conventional antimicrobial therapy. Keeping up with these changes depends on a comprehensive approach, allying understanding of the pathogenesis of disease with the development of new drugs for infective endocarditis. Infection by staphylococci and streptococci is being dissected at the molecular level. New ideas for antimicrobial agents are being developed. These novel insights should help redefine preventive and therapeutic strategies against infective endocarditis.

Infective endocarditis.

Infective endocarditis (IE) is lethal if not aggressively treated with antibiotics alone or in combination with surgery. The epidemiology of this condition has substantially changed over the past four decades, especially in industrialized countries. Once a disease that predominantly affected young adults with previously well-identified valve disease--mostly chronic rheumatic heart disease--IE now tends to affect older patients and new at-risk groups, including intravenous-drug users, patients with intracardiac devices, and patients exposed to healthcare-associated bacteremia. As a result, skin organisms (for example, Staphylococcus spp.) are now reported as the pathogen in these populations more often than oral streptococci, which still prevail in the community and in native-valve IE. Moreover, progress in molecular diagnostics has helped to improve the diagnosis of poorly cultivable pathogens, such as Bartonella spp. and Tropheryma whipplei, which are responsible for blood-culture-negative IE more often than expected. Epidemiological data indicate that IE mostly occurs independently of medico-surgical procedures, and that circumstantial antibiotic prophylaxis is likely to protect only a minute proportion of individuals at risk. Therefore, new strategies to prevent IE--including improvement of dental hygiene, decontamination of carriers of Staphylococcus aureus, vaccination, and, possibly, antiplatelet therapy--must be explored.

Approches diagnostiques des bactéries intracellulaires et des germes fastidieux [Diagnostic approach of intracellular bacteria and fastidious microorganisms].

Obligate or facultative intracellular bacteria are fastidious organisms that do not or poorly grow on conventional culture media. Some of them may be the cause of frequent and potentially severe infections, such as tuberculosis (Myco- bacterium tuberculosis), community-acquired respiratory infections (Legionella spp., Mycoplasma pneumoniae, Chlamydia pneumoniae) or blood culture-negative endocarditis (Coxiella burnetii, Bartonella spp., Tropheryma whipplei). The objective of this paper is to provide a comprehensive summary of the available and recommended diagnostic tests for the detection of these fastidious organisms in clinical practice.