Dolosigranulum pigrum causing nosocomial pneumonia and septicemia

We report a case of non-ventilator-associated nosocomial pneumonia and septicemia due to Dolosigranulum pigrum, a rare gram-positive opportunistic pathogen. The organism was isolated from bronchoalveolar lavage fluid and blood of a debilitated patient. D. pigrum was identified after 16S rRNA gene sequencing.     

Quantitative and qualitative changes in anti-Neu5Gc antibody response following rabbit anti-thymocyte IgG induction in kidney allograft recipients

Antibodies of non-human mammals are glycosylated with carbohydrate antigens, such as galactose-α-1-3-galactose (α-Gal) and N-glycolylneuraminic acid (Neu5Gc). These non-human carbohydrate antigens are highly immunogenic in humans due to loss-of-function mutations of the key genes involved in their synthesis. Such immunogenic carbohydrates are expressed on therapeutic polyclonal rabbit anti-human T-cell IgGs (anti-thymocyte globulin; ATG), the most popular induction treatment in allograft recipients. To decipher the quantitative and qualitative response against these antigens in immunosuppressed patients, particularly against Neu5Gc, which may induce endothelial inflammation in both the graft and the host. We report a prospective study of the antibody response against α-Gal and Neu5Gc-containing glycans following rabbit ATG induction compared to controls. We show a drop in the overall levels of anti-Neu5Gc antibodies at 6 and 12 months post-graft compared to the pre-existing levels due to the major early immunosuppression. However, in contrast, in a cross-sectional study there was a highly significant increase in anti-Neu5Gc IgGs levels at 6 months post-graft in the ATG-treated compared to non-treated patients(P = 0.007), with a clear hierarchy favouring anti-Neu5Gc over anti-Gal response. A sialoglycan microarray analysis revealed that the increased anti-Neu5Gc IgG response was still highly diverse against multiple different Neu5Gc-containing glycans. Furthermore, some of the ATG-treated patients developed a shift in their anti-Neu5Gc IgG repertoire compared with the baseline, recognizing different patterns of Neu5Gc-glycans. In contrast to Gal, Neu5Gc epitopes remain antigenic in severely immunosuppressed patients, who also develop an anti-Neu5Gc repertoire shift. The clinical implications of these observations are discussed.     

The influence of affective state on respiratory muscle activity

Measures of neural respiratory drive through the use of electromyography of the parasternal intercostal muscles (EMGpara) are accurate markers of respiratory load and are reflective of pulmonary function. A previous observation of a significant reduction in EMGpara from a first to second measurement occasion was attributed to participants’ acclimatization to the laboratory environment and a reduction in anxiety. This study therefore aimed to investigate whether manipulation of participants’ affective state would influence EMGpara and related variables. Healthy adult participants underwent measurement of EMGpara and respiratory flow and volume during exposure to four conditions: no stimulus, music, and tense and calm videos. Respiratory rate (RR), raw neural respiratory drive index (rawNRDI, the product of EMGpara in microvolts and RR) and minute ventilation (VE) differed significantly across conditions: RR and VE were significantly higher in the tense condition than all other conditions (all P<0·05); rawNRDI was higher in the tense compared to the calm video condition (P = 0·03). There was also a significant relationship between EMGpara and subjective tension ratings (measured via visual analogue scale) in the tense condition (Spearman's rho = 0·508, P = 0·016), with multivariate modelling indicating significant interactions between rawNRDI and subjective ratings of both tension and calmness. This suggests that anxiety could contribute to elevated respiratory muscle activity and ventilation. Greater consideration should be given to the influence of anxiety when undertaking measurement of respiratory muscle activity to ensure data accurately represent underlying respiratory load.