Amoxicillin for acute lower respiratory tract infection in primary care: subgroup analysis of potential high-risk groups

Background

Antibiotics are of limited overall clinical benefit for uncomplicated lower respiratory tract infection (LRTI) but there is uncertainty about their effectiveness for patients with features associated with higher levels of antibiotic prescribing.

Aim

To estimate the benefits and harms of antibiotics for acute LRTI among those producing coloured sputum, smokers, those with fever or prior comorbidities, and longer duration of prior illness.

Design and setting

Secondary analysis of a randomised controlled trial of antibiotic placebo for acute LRTI in primary care.

Method

Two thousand and sixty-one adults with acute LRTI, where pneumonia was not suspected clinically, were given amoxicillin or matching placebo. The duration of symptoms, rated moderately bad or worse (primary outcome), symptom severity on days 2–4 (0–6 scale), and the development of new or worsening symptoms were analysed in pre-specified subgroups of interest. Evidence of differential treatment effectiveness was assessed in prespecified subgroups by interaction terms.

Results

No subgroups were identified that were significantly more likely to benefit from antibiotics in terms of symptom duration or the development of new or worsening symptoms. Those with a history of significant comorbidities experienced a significantly greater reduction in symptom severity between days 2 and 4 (interaction term −0.28, P = 0.003; estimated effect of antibiotics among those with a past history −0.28 [95% confidence interval = −0.44 to −0.11], P = 0.001), equivalent to three people in 10 rating symptoms as a slight rather than a moderately bad problem. For subgroups not specified in advance antibiotics provided a modest reduction in symptom severity for non-smokers and for those with short prior illness duration (<7 days), and a modest reduction in symptom duration for those with short prior illness duration.

Conclusion

There is no clear evidence of clinically meaningful benefit from antibiotics in the studied high-risk groups of patients presenting in general practice with uncomplicated LRTIs where prescribing is highest. Any possible benefit must be balanced against the side-effects and longer-term effects on antibiotic resistance.     

Human Mate Selection and Addiction: a Conceptual Critique

The authors review past work on modeling human mate selection, and suggest, using illustrations from existing literature on the impact of alcoholism on relationship formation and dissolution and reproduction, that the challenges of adequately characterizing human mate selection have not yet been overcome. Some paths forwards are suggested.     

De-escalating therapy in gastric aggressive lymphoma

The treatment of primary gastric diffuse large B-cell lymphoma (DLBCL) has changed radically over the last 10–15 years, with the abandonment of routine gastrectomy in favor of more conservative therapies. Low-level evidence suggests that consolidation radiotherapy could be avoided in patients with limited-stage DLBCL of the stomach who achieve complete remission after rituximab-CHOP combination. Small, recent prospective trials suggest that selected patients with limited-stage Helicobacter pylori (H. pylori)-positive DLBCL of the stomach and favorable prognostic factors can be managed with antibiotics alone, with excellent disease control and cure rates, keeping chemo-radiotherapy for unresponsive patients. This recommendation should equally regard patients with mucosa-associated lymphoid tissue-related or de novo DLBCL. Future studies should be focused on the establishment of reliable variables able to distinguish the best candidates for exclusive treatment with H. pylori eradication from those who need for conventional chemo-immunotherapy.     

Identification of a common immune signature in murine and human systemic Salmonellosis

Despite the importance of Salmonella infections in human and animal health, the target antigens of Salmonella-specific immunity remain poorly defined. We have previously shown evidence for antibody-mediating protection against invasive Salmonellosis in mice and African children. To generate an overview of antibody targeting in systemic Salmonellosis, a Salmonella proteomic array containing over 2,700 proteins was constructed and probed with immune sera from Salmonella-infected mice and humans. Analysis of multiple inbred mouse strains identified 117 antigens recognized by systemic antibody responses in murine Salmonellosis. Importantly, many of these antigens were independently identified as target antigens using sera from Malawian children with Salmonella bacteremia, validating the study of the murine model. Furthermore, vaccination with SseB, the most prominent antigenic target in Malawian children, provided mice with significant protection against Salmonella infection. Together, these data uncover an overlapping immune signature of disseminated Salmonellosis in mice and humans and provide a foundation for the generation of a protective subunit vaccine.     

Single-cell proteomic chip for profiling intracellular signaling pathways in single tumor cells

We describe a microchip designed to quantify the levels of a dozen cytoplasmic and membrane proteins from single cells. We use the platform to assess protein–protein interactions associated with the EGF-receptor-mediated PI3K signaling pathway. Single-cell sensitivity is achieved by isolating a defined number of cells (n = 0–5) in 2 nL volume chambers, each of which is patterned with two copies of a miniature antibody array. The cells are lysed on-chip, and the levels of released proteins are assayed using the antibody arrays. We investigate three isogenic cell lines representing the cancer glioblastoma multiforme, at the basal level, under EGF stimulation, and under erlotinib inhibition plus EGF stimulation. The measured protein abundances are consistent with previous work, and single-cell analysis uniquely reveals single-cell heterogeneity, and different types and strengths of protein–protein interactions. This platform helps provide a comprehensive picture of altered signal transduction networks in tumor cells and provides insight into the effect of targeted therapies on protein signaling networks.Although signal transduction inhibitors occasionally offer clinical benefit for cancer patients (1), signal flux emanating from oncogenes is often distributed through multiple pathways (2), potentially underlying the failure of most such inhibitors (3). Measuring signal flux through multiple pathways, in response to signal transduction inhibitors, may help uncover network interactions that contribute to therapeutic resistance and that are not predicted by analyzing pathways in isolation (4). The cellular and molecular complexity of a solid tumor microenvironment (5) suggests the need to study signaling in individual cancer cells.Protein–protein interactions within signaling pathways are often elucidated by assessing the levels of relevant pathway proteins in model and tumor-derived cell lines and with various genetic and molecular perturbations. Such interactions, and the implied signaling networks, may also be elucidated via quantitative measurements of multiple pathway-related proteins within single cells (6). At the single-cell level, inhibitory and activating protein–protein relationships, as well as stochastic (single-cell) fluctuations, are revealed. However, most techniques for profiling signaling pathways (7, 8) require large numbers of cells. Single-cell immunostaining (9) is promising, and some flow cytometry (6) techniques are relevant, as discussed below.We describe quantitative, multiplex assays of intracellular signaling proteins from single cancer cells using a platform called the single-cell barcode chip (SCBC). The SCBC is simple in concept: A single or defined number of cells is isolated within an approximately 2 nL volume microchamber that contains an antibody array (10) for the capture and detection of a panel of proteins. The SCBC design (11) permits lysis of each individual trapped cell.Intracellular staining flow cytometry can assay up to 11 phosphoproteins from single cells (6). Our SCBC can profile a similar size panel, but only for approximately 100 single cells per chip. Each protein is assayed twice, yielding some statistical assessment for each experiment. The SCBC is a relatively simple platform and only requires a few hundred cells per assay.We used the SCBC to study signal transduction in glioblastoma multiforme (GBM), a primary malignant brain tumor (12). GBM has been genetically characterized, yet the nature of signaling pathways downstream of key oncogenic mutations, such as epidermal growth factor receptor activating mutation (EGFRvIII) and phosphatase and tensin homolog (PTEN) tumor suppressor gene loss associated with receptor tyrosine kinase (RTK)/PI3K signaling, are incompletely understood (13–15). Single-cell experiments may also help resolve the characteristic heterogeneity of GBM.We interrogated 11 proteins directly or potentially associated with PI3K signaling (see SI Appendix, Methods I) through three isogenic GBM cell lines: U87 (expressing wild-type p53, mutant PTEN, and low levels of wild-type EGFR, no EGFRvIII) (16, 17), U87 EGFRvIII (U87 cells stably expressing EGFRvIII deletion mutant), and U87 EGFRvIII PTEN (U87 cells coexpressing EGFRvIII and PTEN) (18). Fig. 1 diagrams this biology. Each cell line was investigated under conditions of standard cell culture, in response to EGF stimulation, and after erlotinib treatment followed by EGF stimulation. The proteins assayed represented RTKs and proteins signifying activation of PI3K and MAPK signaling. They were (p- denotes phosphorylation) p-Src, p-mammalian target of rapamycin (p-mTOR), p-p70 ribosomal protein S6 kinase (p-p70S6K), p-glycogen synthase kinase-3 (p-GSK-3α/β), p-p38 mitogen activated protein kinase (p-p38α), p-extracellular regulated kinase (p-ERK), p-c-Jun N-terminal kinase (p-JNK2), p-platelet derived growth factor receptor β (p-PDGFRβ), p-vascular endothelial growth factor receptor 2 (p-VEGFR2), tumor protein 53 (P53), and total EGFR.Open in a separate windowFig. 1.The PI3K pathway activated by EGF-stimulated EGFR or by the constitutively activated EGFRvIII. All proteins in light blue with central yellow background were assayed. Orange background proteins were expressed in the cell lines U87 EGFRvIII or U87 EGFRvIII PTEN. The oval, yellow background components are the investigated molecular perturbations.     

Serological monitoring of protection of sheep against Echinococcus granulosus induced by the EG95 vaccine

Although immunity to Echinococcus granulosus in sheep has been shown to be antibody-mediated and complement-dependent and can be passively transferred in colostrum, in animals vaccinated with EG95, the relationship between protection against an oral challenge infection with E. granulosus eggs and anti-EG95 IgG ELISA absorbance values at the time of challenge has not been satisfactorily proven. Using a combination of results from three EG95 vaccination trials, we have found that the IgG ELISA absorbance at the time of challenge infection explains approximately 50% (P ≤ 0·001) of the variability in the percentage protection against an oral challenge with E. granulosus eggs (transformed with arcsin).