Six broad-host-range plasmid vectors were developed to study gene expression in Bartonella henselae. The vectors were used to express a ␤-galactosidase reporter gene in B. henselae and to generate antisense RNA for gene knockdown. When applied to ompR, a putative transcription response regulator of B. henselae, this antisense RNA gene knockdown strategy reduced bacterial invasion of human endothelial cells by over 60%.

Background: An optimal cytomegalovirus (CMV) prevention strategy following solid organ transplantation (SOT) remains uncertain. This study reports on the rates of CMV events following a change in a local prevention guideline involving increased surveillance, earlier transition to oral valganciclovir, and decreased CMV-immunoglobulin use.Methods: A retrospective cohort study utilizing historical controls evaluated the rates of CMV invasive disease pre-and post-intervention among pediatric heart, liver, and kidney recipients. Outcomes were recorded for the 4 years pre-and post-intervention, 9/2009-10/2017. Logistic regression was used to estimate the risk of a CMV event.Results: There was no difference in the rates of CMV invasive disease between the two study groups (P = 1). An increase in the detection of CMV events occurred (P = .04), predominantly asymptomatic CMV infection. This increase was independently associated with increased surveillance testing among high-risk heart and liver recipients, aOR 1.08(1. 06-1.12). Surprisingly, 28.9% of CMV events occurred during antiviral prophylaxis. Conclusions:Modification of the local CMV prevention guideline did not result in an increase in CMV invasive disease. CMV events occurred while on prophylaxis, highlighting a potential difference from adult solid organ transplant (SOT) and emphasizing the potential need for monitoring on prophylaxis in the pediatric population. K E Y W O R D Scytomegalovirus, pediatric, prevention, solid organ transplantation

Streptococcus pneumoniae is an invasive organism that causes a wide range of common diseases, including sinusitis, acute otitis media, and pneumonia. Splenic abscesses and purpura fulminans (PF) are rare complications of pneumococcal disease. Splenic abscesses caused by S pneumoniae have only been reported in the adult literature. PF has been described in the pediatric population as a rare complication in patients with invasive pneumococcal disease (IPD) with and without underlying immunological disorders such as asplenia. Here, we report a patient with IPD complicated by splenic abscesses and PF. Our patient initially presented with bacteremia, septic shock, and disseminated intravascular coagulation. She subsequently developed PF and splenic abscesses. She survived her illness after receiving a total of 8 weeks of antibiotic therapy. This case highlights 2 rare complications of IPD and demonstrates the need to keep pneumococcal disease in the differential diagnosis even in children whose vaccination status is up to date.

Background Peritonitis is a significant cause of morbidity and healthcare cost among pediatric patients undergoing peritoneal dialysis. Culture-negative peritonitis has been associated with an increased risk of technique failure. Known risk factors for culture-negative peritonitis are related to the process of collection and sample processing for culture, but additional studies are needed. A culture detection rate of 16.7% was identified among our patients undergoing peritoneal dialysis, which is below the national benchmark of ≥ 85%. Our primary objective of this quality improvement project was to improve culture detection rates. Methods Interventions were developed aimed at standardizing the process of effluent collection and laboratory processing, timely collection and processing of samples, and addressing other modifying risk factors for lack of bacterial growth from culture. These interventions included direct inoculation of effluent into blood culture bottles at bedside and use of an automated blood culture system. Two Plan-Do-Study-Act cycles were completed prior to moving to the sustain phase. Results The culture detection rate improved from 16.7% (pre-intervention) to 100% (post-intervention). A decrease in the median process time also occurred from 83 min (pre-intervention) to 53 min (post-intervention). An individual and moving range chart identified a decrease in both the centerline (mean) and upper control limit, indicating that the process became more reliable during the sustain phase. Conclusions An improvement in process time and culture positivity rate occurred following standardization of our PD fluid culture process. Future studies should be aimed at the impact of the components of collection and processing methods on the effluent culture yield. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information . Supplementary Information The online version contains supplementary material including a Graphical Abstract available at 10.1007/s00467-022-05533-1.