Hemophagocytic lymphohistiocytosis secondary to unrecognized Bartonella henselae infection: a case report.

BACKGROUND: Bartonella henselae is a species of intracellular bacteria transmitted to humans through animal bites and scratches contaminated with the feces of arthropod vectors, and are most commonly associated with cat exposure although transmission from other mammals has been reported. Bartonella henselae infection has a spectrum of clinical manifestations and has rarely been reported as cause of hemophagocytic lymphohistiocytosis (HLH) in immunocompromised hosts. CASE PRESENTATION: We present a report of Bartonella henselae infection progressing to HLH in an immunocompetent patient. The patient initially presented with regional lymphadenopathy but the diagnosis was not suspected as the patient reported no exposure to cats. On further history, he did report a scratch from a dog prior to development of symptoms. The patient was treated with methylprednisolone, intravenous immunoglobulin and anakinra for the HLH and three months of Doxycycline for Bartonella infection, with complete resolution of symptoms. CONCLUSIONS: Although commonly associated with cat exposure, Bartonella henselae transmission can occur after exposure to other animals and vectors including dogs and clinicians need to maintain an index of suspicion for timely diagnosis. Bartonella henselae is associated with a spectrum of clinical manifestations which can include disseminated infection with severe complications such as hemophagocytic lymphohistiocytosis. Prompt initiation of Bartonella treatment is essential when thought to be the trigger for hemophagocytic lymphohistiocytosis although the optimal treatment regimen is unclear.

Biomolecular Self-Assembly of Nanorings on a Viral Protein Template.

Although there have been many advances in synthesizing nanoparticles, their assembly into deterministic and controllable patterns remains a major challenge. Biological systems operate at the nanoscale, building structural components with great chemical specificity that enable the processes of life. By adapting them to our needs, it is possible to utilize well-defined and well-controlled scaffolds to produce materials with novel properties resulting from precise ordering on the nanoscale. This approach uses spatial arrangement instead of nanoparticle size, shape, or composition to control material properties through the collective interactions between neighboring nanoparticles. Here, we demonstrate the use of tobacco mosaic virus (TMV) coat protein as a template to self-assemble plasmonic nanoparticles. Surface plasmons are resonant oscillations in the free electrons of a metal that are excited through interaction with light. These plasmonic oscillations can couple together, giving rise to more complex modes like plasmonic ring resonances that can be used to tune the response to incident light. By exploiting the self-assembling properties and chemical addressability of TMV coat protein, we can utilize site-directed mutagenesis and bioconjugation strategies to produce highly symmetrical plasmonic nanorings, as evidenced by transmission electron microscopy (TEM). Thus, we show the utility of viral proteins in designing and assembling nanostructured building blocks for advanced materials.

Viral-based nanomaterials for plasmonic and photonic materials and devices.

Over the last decade, viruses have established themselves as a powerful tool in nanotechnology. Their proteinaceous capsids benefit from biocompatibility, chemical addressability, and a variety of sizes and geometries, while their ability to encapsulate, scaffold, and self-assemble enables their use for a wide array of purposes. Moreover, the scaling up of viral-based nanotechnologies is facilitated by high capsid production yield and speed, which is particularly advantageous when compared with slower and costlier lithographic techniques. These features enable the bottom-up fabrication of photonic and plasmonic materials, which relies on the precise arrangement of photoactive material at the nanoscale to control phenomena such as electromagnetic wave propagation and energy transfer. The interdisciplinary approach required for the fabrication of such materials combines techniques from the life sciences and device engineering, thus promoting innovative research. Materials with applications spanning the fields of sensing (biological, chemical, and physical sensors), nanomedicine (cellular imaging, drug delivery, phototherapy), energy transfer and conversion (solar cells, light harvesting, photocatalysis), metamaterials (negative refraction, artificial magnetism, near-field amplification), and nanoparticle synthesis are considered with exclusive emphasis on viral capsids and protein cages. This article is categorized under: Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.

Impact of Reported Beta-Lactam Allergy on Inpatient Outcomes: A Multicenter Prospective Cohort Study.

BACKGROUND: Reported allergy to beta-lactam antibiotics is common and often leads to unnecessary avoidance in patients who could tolerate these antibiotics. We prospectively evaluated the impact of these reported allergies on clinical outcomes. METHODS: We conducted a trainee-led prospective cohort study to determine the burden and clinical impact of reported beta-lactam allergy on patients seen by infectious diseases consultation services at 3 academic hospitals. The primary outcome was a composite measure of readmission for the same infection, acute kidney injury, Clostridium difficile infection, or drug-related adverse reactions requiring discontinuation. Predictors of interest were history of beta-lactam allergy and receipt of preferred beta-lactam therapy. RESULTS: Among 507 patients, 95 (19%) reported beta-lactam allergy; preferred therapy was a beta-lactam in 72 (76%). When beta-lactam therapy was preferred, 25 (35%) did not receive preferred therapy due to their report of allergy even though 13 (52%) reported non-severe prior reactions. After adjustment for confounders, patients who did not receive preferred beta-lactam therapy were at greater risk of adverse events (adjusted odds ratio [aOR], 3.1; 95% confidence interval [CI], 1.28-7.89) compared with those without reported allergy. In contrast, patients who received preferred beta-lactam therapy had a similar risk of adverse events compared with patients not reporting allergy (aOR, 1.33; 95% CI, .62-2.87). CONCLUSIONS: Avoidance of preferred beta-lactam therapy in patients who report allergy is associated with an increased risk of adverse events. Development of inpatient programs aimed at accurately identifying beta-lactam allergies to safely promote beta-lactam administration among these patients is warranted.

An educational forum to engage infectious diseases and microbiology residents in resource stewardship modelled after the Choosing Wisely campaign.

BACKGROUND: Rising costs present a major threat to the sustainability of health care delivery. Resource stewardship is increasingly becoming an expected competency of physicians. The Choosing Wisely framework was used to introduce resource stewardship at a national educational retreat for infectious disease and microbiology residents. METHODS: During the 2014 Annual Canadian Infectious Disease and Microbiology Resident Retreat in Toronto, Ontario, infectious disease (n=50) and microbiology (n=17) residents representing 11 Canadian universities from six provinces, were invited to participate in a modified Delphi panel. Participants were asked, in advance of the retreat, to submit up to five practices that infectious disease and microbiology specialists should not routinely perform due to lack of proven benefit(s) and/or potential harm to patients. Submissions were discussed in small and large group forums using an iterative approach involving electronic polling until consensus was reached for five practices. A finalized list was created for both educational purposes and for residents to consider enacting; however, it was not intended to replace formal society-endorsed statements. A follow-up survey at two-months was conducted. RESULTS: Consensus was reached by the residents regarding five low-value practices within the purview of infectious diseases and microbiology physicians. After the retreat, 20 participants (32%) completed the follow-up survey. The majority of respondents (75%) believed that the session was at least as relevant as other sessions they attended at the retreat, including 95% indicating that at least some of the material discussed was new to them. Since returning to their home institutions, nine (45%) respondents have incorporated what they learned into their daily practice; four (20%) reported that they have considered initiating a project related to the session; and one (5%) reported having initiated a project. CONCLUSIONS: The present educational forum demonstrated that trainees can become actively engaged in the identification and discussion of low-value practices. Embedding residence training programs with resource stewardship education will be necessary to improve the value of care offered by the future members of our profession.

HISTORIQUE: Les coûts croissants représentent une menace importante pour la pérennité des soins de santé. De plus en plus, on s'attend que les médecins aient les compétences nécessaires pour gérer les ressources. Lors d'une journée de réflexion nationale pour les résidents en infectiologie et en microbiologie, la gestion des ressources a été abordée conformément au cadre Choosing Wisely. MÉTHODOLOGIE: Pendant la journée de réflexion canadienne annuelle de 2014 pour les résidents en infectiologie et en microbiologie tenue à Toronto, en Ontario, des résidents en infectiologie (n=50) et en microbiologie (n=17) représentant 11 universités canadiennes réparties dans six provinces ont été invités à participer à un groupe Delphi modifié. Avant la journée de réflexion, ils ont été invités à soumettre jusqu'à cinq pratiques que les spécialistes de l'infectiologie ou de la microbiologie ne devraient pas effectuer systématiquement parce que leurs avantages ne sont pas démontrés ou qu'elles comportent des risques potentiels pour les patients. Ils ont examiné ces pratiques lors de forums en petits et grands groupes selon une méthode itérative par sondage électronique, jusqu'à atteindre un consensus pour cinq pratiques. Une liste définitive a été créée pour des besoins d'éducation et pour que les résidents envisagent de la respecter. Cette liste ne visait toutefois pas à remplacer les documents officiels approuvés par la Société. Un sondage de suivi a été effectué au bout de deux mois. RÉSULTATS: Les résidents sont parvenus à un consensus sur cinq pratiques de faible valeur qui relèvent des médecins en infectiologie et en microbiologie. Après la journée de réflexion, 20 participants (32 %) ont rempli le sondage de suivi. La majorité d'entre eux (75 %) trouvaient que cette séance était au moins aussi pertinente que les autres séances auxquelles ils avaient assisté pendant la journée de réflexion, et 95 % ont indiqué qu'au moins une partie de ce qui avait été abordé était nouveau pour eux. Depuis leur retour au sein de leur établissement, neuf (45 %) répondants avaient intégré ce qu'ils avaient appris à leur pratique, quatre (20 %) ont déclaré avoir envisagé un projet lié à la séance et un (5 %) a affirmé avoir lancé un projet. CONCLUSIONS: Le présent forum d'éducation a démontré que les résidents peuvent s'investir pour cerner les pratiques de faible valeur et en discuter. Il faudra intégrer la gérance de l'éducation aux programmes de résidence pour améliorer la valeur des soins offerts par les futurs membres de notre profession.