Multiplexed Functional Assessment of Genetic Variants in CARD11.

Genetic testing has increased the number of variants identified in disease genes, but the diagnostic utility is limited by lack of understanding variant function. CARD11 encodes an adaptor protein that expresses dominant-negative and gain-of-function variants associated with distinct immunodeficiencies. Here, we used a "cloning-free" saturation genome editing approach in a diploid cell line to simultaneously score 2,542 variants for decreased or increased function in the region of CARD11 associated with immunodeficiency. We also described an exon-skipping mechanism for CARD11 dominant-negative activity. The classification of reported clinical variants was sensitive (94.6%) and specific (88.9%), which rendered the data immediately useful for interpretation of seven coding and splicing variants implicated in immunodeficiency found in our clinic. This approach is generalizable for variant interpretation in many other clinically actionable genes, in any relevant cell type.

First United States Outbreak of Mycobacterium abscessus Hand and Foot Disease Among Children Associated With a Wading Pool.

BACKGROUND: Mycobacterium abscessus, an emerging pathogen in healthcare settings, has rarely been associated with community outbreaks. During February-May 2013, Idaho public health officials and pediatric infectious disease physicians investigated an outbreak of M abscessus skin infections in children whose only common exposure was an indoor wading pool. METHODS: Healthcare providers and parents reported possible M abscessus cases. We used a standardized questionnaire to interview parents of affected children. Clinical specimens were submitted for mycobacterial examination. We conducted an environmental investigation of the pool. Microbial isolates from clinical and environmental samples were identified by sequencing polymerase chain reaction amplicons and underwent pulsed-field gel electrophoresis. RESULTS: Twelve cases were identified. Specimens from 4 of 7 children grew M abscessus or Mycobacterium abscessus/Mycobacterium chelonae . Ten (83%) of 12 children were female; median age was 3 years (range, 2 to 6 years); and all were immunocompetent. Pool maintenance did not fully comply with Idaho state rules governing pool operation. Mycobacterium abscessus/chelonae was isolated from pool equipment. Pulsed-field gel electrophoresis composite patterns were 87% similar between isolates from the pool ladder and 1 patient, and they were 90% similar between isolates from 2 patients. Environmental remediation included hyperchlorination, scrubbing and disinfection of pool surfaces, draining the pool, and replacement of worn pool materials. CONCLUSIONS: Immunocompetent children acquired M abscessus cutaneous infection involving hands and feet after exposure to a wading pool. Environmental remediation and proper pool maintenance likely halted transmission. Medical and public health professionals' collaboration effectively detected and controlled an outbreak caused by an emerging recreational waterborne pathogen.

Bacteremia and malaria in Tanzanian children hospitalized for acute febrile illness.

We recorded the reason for presentation to a rural hospital in an area endemic for malaria in 909 children between January 2006 and March 2009. Blood smears were examined for Plasmodium falciparum parasites, and blood spots dried on filter paper were prepared for 464 children. A PCR assay utilizing the stored blood spots was developed for Streptococcus pneumoniae (lytA) and Haemophilus influenzae (pal). Malaria was present in 299 children whose blood was tested by polymerase chain reaction (PCR); 19 had lytA and 15 had pal. The overall prevalence of lytA was 25 of the 464 children, while that of pal was 18 children. Fever was present in 369 children of whom 19 had lytA DNA while 11 had pal DNA detected. Of the 95 afebrile children, six had lytA and seven pal. We conclude that there are no clinical features that distinguish malaria alone from bacteremia alone or the presence of both infections.

Central venous catheter repair is associated with an increased risk of bacteremia and central line-associated bloodstream infection in pediatric patients.

BACKGROUND: Repair of broken central venous catheters (CVCs) is common in pediatric patients. We hypothesized that this practice predisposes to bacteremia and central line-associated bloodstream infections (CLABSI). METHODS: We conducted a retrospective case-crossover study of pediatric patients 1 month to 21 years of age with CVC breakages who underwent a first-time repair at our institution, using repair kits provided by CVC manufacturers. We compared rates of bacteremia and CLABSI (defined by Centers for Disease Control and Prevention criteria) in the 30 days prerepair (control period) and the 30 days postrepair (exposure period), with adjustment for within-patient correlation using conditional Poisson regression. RESULTS: The mean prerepair rate of bacteremia was 9.9 per 1000 catheter-days, which increased to 24.5 postrepair, resulting in an adjusted incidence rate ratio (IRR) of 1.87 (95% CI: 1.05-3.33, P = 0.034). Risk of CLABSI demonstrated a greater than 2-fold increase (IRR: 2.15, 95% CI: 1.02-4.53, P = 0.045) when all catheter-days were included, and a 4-fold increase when days on antibiotics were excluded (IRR: 4.07, 95% CI: 1.43-11.57, P = 0.008). CONCLUSIONS: We found that repair of a broken CVC was associated with a 2- to 4-fold higher risk of developing CLABSI within 30 days of repair in pediatric patients. Further studies are needed to determine interventions to reduce this risk and to better define the relative merits of CVC repair compared with replacement in selected patient populations.

Outcomes and duration of Pneumocystis jiroveci pneumonia therapy in infants with severe combined immunodeficiency.

This retrospective review of patients with severe combined immunodeficiency and Pneumocystis jiroveci pneumonia (PCP) evaluated the relationship between duration of therapy to treat PCP and overall survival. We found that 80% of patients receiving only 21 days of antibiotics survived to 12 months beyond hematopoietic cell transplant, whereas only 25% of patients who required longer treatment for PCP survived to stem cell engraftment.

Fosmidomycin plus clindamycin for treatment of pediatric patients aged 1 to 14 years with Plasmodium falciparum malaria.

Fosmidomycin plus clindamycin was shown to be efficacious in the treatment of uncomplicated Plasmodium falciparum malaria in a small cohort of pediatric patients aged 7 to 14 years, but more data, including data on younger children with less antiparasitic immunity, are needed to determine the potential value of this new antimalarial combination. We conducted a single-arm study to improve the precision of efficacy estimates for an oral 3-day fixed-ratio combination of fosmidomycin and clindamycin at 30 and 10 mg/kg of body weight, respectively, every 12 hours for the treatment of uncomplicated P. falciparum malaria in 51 pediatric outpatients aged 1 to 14 years. Fosmidomycin plus clindamycin was generally well tolerated, but relatively high rates of treatment-associated neutropenia (8/51 [16%]) and falls of hemoglobin concentrations of > or =2 g/dl (7/51 [14%]) are of concern. Asexual parasites and fever were cleared within median periods of 42 h and 38 h, respectively. All patients who could be evaluated were parasitologically and clinically cured by day 14 (49/49; 95% confidence interval [CI], 93 to 100%). The per-protocol, PCR-adjusted day 28 cure rate was 89% (42/47; 95% CI, 77 to 96%). Efficacy appeared to be significantly reduced in children aged 1 to 2 years, with a day 28 cure rate of only 62% for this small subgroup (5/8). The inadequate efficacy in children of <3 years highlights the need for continued systematic studies of the current dosing regimen, which should include randomized trial designs.

Short-course regimens of artesunate-fosmidomycin in treatment of uncomplicated Plasmodium falciparum malaria.

Fosmidomycin is effective against malaria, but it needs to be given for > or =4 days when used alone. We conducted a study of 50 children with Plasmodium falciparum malaria to evaluate the safety and efficacy of consecutively shortened regimens of artesunate-fosmidomycin (1 to 2 mg/kg of body weight and 30 mg/kg of body weight, respectively; doses given every 12 hours). All dosing regimens were well tolerated. Artesunate-fosmidomycin acted rapidly, resulting in consolidated geometric mean parasite and fever clearance times of 24 h and 15 h, respectively. Treatment regimens of > or =2 days led to cure ratios of 100% by day 14 (39/39; 95% confidence interval [95% CI], 91% to 100%). Most importantly, the 3-day regimen achieved 100% cure on day 28 (10/10; 95% CI, 69% to 100%). Treatment with artesunate-fosmidomycin was associated with transient grade I or II neutropenia (absolute neutrophil counts of 750 to 1,200/microl and 400 to 749/microl, respectively) in six or two patients, respectively. Artesunate-fosmidomycin demonstrates the feasibility and potential value of short-course artemisinin-based combination chemotherapy with rapidly eliminated combination partners.