Performance of MALDI-TOF MS, real-time PCR, antigen detection, and automated biochemical testing for the identification of Burkholderia pseudomallei.

Burkholderia pseudomallei is the causative agent of melioidosis, a disease highly endemic to Southeast Asia and northern Australia, though the area of endemicity is expanding. Cases may occur in returning travelers or, rarely, from imported contaminated products. Identification of B. pseudomallei is challenging for laboratories that do not see this organism frequently, and misidentifications by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and automated biochemical testing have been reported. The in vitro diagnostic database for use with the Vitek MS has recently been updated to include B. pseudomallei and we aimed to validate the performance for identification in comparison to automated biochemical testing with the Vitek 2 GN card, quantitative real-time polymerase chain reaction (qPCR) targeting the type III secretion system, and capsular polysaccharide antigen detection using a lateral flow immunoassay (LFA). We tested a "derivation" cohort including geographically diverse B. pseudomallei and a range of closely related Burkholderia species, and a prospective "validation" cohort of B. pseudomallei and B. cepacia complex clinical isolates. MALDI-TOF MS had a sensitivity of 1.0 and specificity of 1.0 for the identification and differentiation of B. pseudomallei from related Burkholderia species when a certainty cutoff of 99.9% was used. In contrast, automated biochemical testing for B. pseudomallei identification had a sensitivity of 0.83 and specificity of 0.88. Both qPCR and LFA correctly identified all B. pseudomallei isolates with no false positives. Due to the high level of accuracy, we have now incorporated MALDI-TOF MS into our laboratory's B. pseudomallei identification workflow.IMPORTANCEBurkholderia pseudomallei causes melioidosis, a disease associated with high morbidity and mortality that disproportionately affects rural areas in Southeast Asia and northern Australia. The known area of endemicity is expanding and now includes the continental United States. Laboratory identification can be challenging which may result in missed or delayed diagnoses and poor patient outcomes. In this study, we compared mass spectrometry using an updated spectral database with multiple other methods for B. pseudomallei identification and found mass spectrometry highly accurate. We have therefore incorporated this fast and cost-effective method into our laboratory's workflow for B. pseudomallei identification.

Lower Rates of Staphylococcus aureus Bloodstream Infection in Patients on Hemodialysis Receiving Trimethoprim-Sulfamethoxazole Melioidosis Prophylaxis.

Hemodialysis is a risk factor for Staphylococcus aureus bloodstream infection (SAB). In this single-center study, SAB rates were 56% lower during the monsoonal wet season when patients on hemodialysis receive supervised melioidosis prophylaxis with trimethoprim-sulfamethoxazole. This intervention may reduce SAB rates in high-risk patients; however, further targeted studies are required.

Clinical Presentation and Outcomes Following Infection With Vibrio spp, Aeromonas spp, Chromobacterium violaceum, and Shewanella spp Water-Associated Organisms in Tropical Australia, 2015-2022.

Background: Water-associated bacterial infections cause a wide spectrum of disease. Although many of these infections are typically due to human host commensal Staphylococcal or Streptococcal spp, water exposure can result in infections with environmental gram negatives such as Vibrio spp, Aeromonas spp, Chromobacterium violaceum, and Shewanella spp (collectively VACS). Methods: We performed a retrospective analysis of the epidemiology, clinical presentation, and outcomes of deep and superficial infections associated with VACS organisms in our health service between 1 January 2015 and 31 December 2023. Results: We identified 317 patient episodes of infection with VACS organisms over this period. Of these, Aeromonas spp (63%) was the most common, followed by Vibrio spp (19%), Shewanella spp (13%), and C violaceum (5%). The majority were isolated from males (74.4%) and involved the lower limb (67.5%). Mild infections were more common than severe presentations, with only 15 (4.7%) admissions to the intensive care unit and 8 (2.5%) deaths. Colonization occurred in 6.9% of patients, in contrast to the perceived severity of some of these bacteria. Copathogens were common and included Staphylococcus aureus (48%) and enteric bacteria (57%). The majority of patients (60%) had no documented water exposure. Initial empiric antimicrobial therapy presumptively covered the susceptibilities of the isolated organisms in 47.3% of patients; however, a lack of VACS-covering empirical therapy was not associated with readmission. Conclusions: The isolation of a VACS organism in our setting was often not associated with documented water exposure, which has implications for empiric antimicrobial therapy. Severe disease and death were uncommon.

Screening and Prophylaxis for Venous Thromboembolism in Pediatric Surgery: A Systematic Review.

OBJECTIVE: The American Pediatric Surgical Association Outcomes and Evidence-Based Practice Committee conducted a systematic review to describe the epidemiology of venous thromboembolism (VTE) in pediatric surgical and trauma patients and develop recommendations for screening and prophylaxis. METHODS: The Medline (Ovid), Embase, Cochrane, and Web of Science databases were queried from January 2000 through December 2021. Search terms addressed the following topics: incidence, ultrasound screening, and mechanical and pharmacologic prophylaxis. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were followed. Consensus recommendations were derived based on the best available literature. RESULTS: One hundred twenty-four studies were included. The incidence of VTE in pediatric surgical populations is 0.29% (Range = 0.1%-0.48%) and directly correlates with surgery type, transfusion, prolonged anesthesia, malignancy, congenital heart disease, inflammatory bowel disease, infection, and female sex. The incidence of VTE in pediatric trauma populations is 0.25% (Range = 0.1%-0.8%) and directly correlates with injury severity, major surgery, central line placement, body mass index, spinal cord injury, and length-of-stay. Routine ultrasound screening for VTE is not recommended. Consider sequential compression devices in at-risk nonmobile, pediatric surgical patients when an appropriate sized device is available. Consider mechanical prophylaxis alone or with pharmacologic prophylaxis in adolescents >15 y and post-pubertal children <15 y with injury severity scores >25. When utilizing pharmacologic prophylaxis, low molecular weight heparin is superior to unfractionated heparin. CONCLUSIONS: While VTE remains an infrequent complication in children, consideration of mechanical and pharmacologic prophylaxis is appropriate in certain populations. TYPE OF STUDY: Systematic Review of level 2-4 studies. LEVEL OF EVIDENCE: Level 3-4.

Fungal Keratitis, Epidemiology and Outcomes in a Tropical Australian Setting.

BACKGROUND: Fungal keratitis is an ophthalmic emergency that can cause visual impairment and blindness. We reviewed the epidemiology and clinical features of fungal keratitis in a tropical Australian setting. OBJECTIVES: To document the clinical and microbiological characteristics of fungal keratitis in an Australian tropical setting. METHODS: A retrospective cohort study of patients with fungal keratitis from October 2014 to December 2022 was conducted at Royal Darwin Hospital, Northern Territory, Australia. We reviewed all patients with culture-proven fungal keratitis and their outcomes. RESULTS: There were 31 patients identified. Aboriginal and Torres Strait Islander (ATSI) patients were of a significantly younger median age (28 years) compared to non-ATSI patients (42 years), and they also presented later to health care. Contact lens use and ocular trauma were the most common predisposing factors. Most patients presented with a corneal infiltrate and corneal epithelial defect, and the central visual axis was affected in 54% of patients. Curvularia spp. and Fusarium spp. were the commonest causative fungi (39% and 30% respectively). CONCLUSIONS: Our series is different and reveals a wider range of fungal species identified over the 7 years of the study, in particular, a range of Curvularia spp. were detected. Access to eye health services in rural and remote settings is important, particularly for ATSI patients, as morbidity remains high.

Genomic Surveillance of Invasive Meningococcal Disease During a National MenW Outbreak in Australia, 2017-2018.

Background: In Australia, invasive meningococcal disease (IMD) incidence rapidly increased between 2014 and 2017 due to rising serogroup W (MenW) and MenY infections. We aimed to better understand the genetic diversity of IMD during 2017 and 2018 using whole genome sequencing data. Methods: Whole genome sequencing data from 440 Australian IMD isolates collected during 2017 and 2018 and 1737 international MenW:CC11 isolates collected in Europe, Africa, Asia, North America, and South America between 1974 and 2020 were used in phylogenetic analyses; genetic relatedness was determined from single-nucleotide polymorphisms. Results: Australian isolates were as follows: 181 MenW (41%), 144 MenB (33%), 88 MenY (20%), 16 MenC (4%), 1 MenW/Y (0.2%), and 10 nongenogroupable (2%). Eighteen clonal complexes (CCs) were identified, and 3 (CC11, CC23, CC41/44) accounted for 78% of isolates (343/440). These CCs were associated with specific serogroups: CC11 (n = 199) predominated among MenW (n = 181) and MenC (n = 15), CC23 (n = 80) among MenY (n = 78), and CC41/44 (n = 64) among MenB (n = 64). MenB isolates were highly diverse, MenY were intermediately diverse, and MenW and MenC isolates demonstrated the least genetic diversity. Thirty serogroup and CC-specific genomic clusters were identified. International CC11 comparison revealed diversification of MenW in Australia. Conclusions: Whole genome sequencing comprehensively characterized Australian IMD isolates, indexed their genetic variability, provided increased within-CC resolution, and elucidated the evolution of CC11 in Australia.

Genetic drift drives faster-Z evolution in the salmon louse Lepeophtheirus salmonis.

How sex chromosomes evolve compared to autosomes remains an unresolved question in population genetics. Most studies focus on only a handful of taxa, resulting in uncertainty over whether observed patterns reflect general processes or idiosyncrasies in particular clades. For example, in female heterogametic (ZW) systems, bird Z chromosomes tend to evolve quickly but not adaptively, while in Lepidopterans they evolve adaptively, but not always quickly. To understand how these observations fit into broader evolutionary patterns, we explore Z chromosome evolution outside of these two well-studied clades. We utilize a publicly available genome, gene expression, population, and outgroup data in the salmon louse Lepeophtheirus salmonis, an important agricultural pest copepod. We find that the Z chromosome is faster evolving than autosomes, but that this effect is driven by increased drift rather than adaptive evolution. Due to high rates of female reproductive failure, the Z chromosome exhibits a slightly lower effective population size than the autosomes which is nonetheless to decrease efficiency of hemizygous selection acting on the Z. These results highlight the usefulness of organismal life history in calibrating population genetic expectations and demonstrate the value of the ever-expanding wealth of publicly available data to help resolve outstanding evolutionary questions.

GAPS phase II: development and pilot results of the global assessment in pediatric surgery, an evidence-based pediatric surgical capacity assessment tool for low-resource settings.

PURPOSE: Pediatric surgical care in low- and middle-income countries is often hindered by systemic gaps in healthcare resources, infrastructure, training, and organization. This study aims to develop and validate the Global Assessment of Pediatric Surgery (GAPS) to appraise pediatric surgical capacity and discriminate between levels of care across diverse healthcare settings. METHODS: The GAPS Version 1 was constructed through a synthesis of existing assessment tools and expert panel consultation. The resultant GAPS Version 2 underwent international pilot testing. Construct validation categorized institutions into providing basic or advanced surgical care. GAPS was further refined to Version 3 to include only questions with a > 75% response rate and those that significantly discriminated between basic or advanced surgical settings. RESULTS: GAPS Version 1 included 139 items, which, after expert panel feedback, was expanded to 168 items in Version 2. Pilot testing, in 65 institutions, yielded a high response rate. Of the 168 questions in GAPS Version 2, 64 significantly discriminated between basic and advanced surgical care. The refined GAPS Version 3 tool comprises 64 questions on: human resources (9), material resources (39), outcomes (3), accessibility (3), and education (10). CONCLUSION: The GAPS Version 3 tool presents a validated instrument for evaluating pediatric surgical capabilities in low-resource settings.

Management of Gastroschisis: Timing of Delivery, Antibiotic Usage, and Closure Considerations (A Systematic Review From the American Pediatric Surgical Association Outcomes & Evidence Based Practice Committee).

BACKGROUND: No consensus exists for the initial management of infants with gastroschisis. METHODS: The American Pediatric Surgical Association (APSA) Outcomes and Evidenced-based Practice Committee (OEBPC) developed three a priori questions about gastroschisis for a qualitative systematic review. We reviewed English-language publications between January 1, 1970, and December 31, 2019. This project describes the findings of a systematic review of the three questions regarding: 1) optimal delivery timing, 2) antibiotic use, and 3) closure considerations. RESULTS: 1339 articles were screened for eligibility; 92 manuscripts were selected and reviewed. The included studies had a Level of Evidence that ranged from 2 to 4 and recommendation Grades B-D. Twenty-eight addressed optimal timing of delivery, 5 pertained to antibiotic use, and 59 discussed closure considerations (Figure 1). Delivery after 37 weeks post-conceptual age is considered optimal. Prophylactic antibiotics covering skin flora are adequate to reduce infection risk until definitive closure. Studies support primary fascial repair, without staged silo reduction, when abdominal domain and hemodynamics permit. A sutureless repair is safe, effective, and does not delay feeding or extend length of stay. Sedation and intubation are not routinely required for a sutureless closure. CONCLUSIONS: Despite the large number of studies addressing the above-mentioned facets of gastroschisis management, the data quality is poor. A wide variation in gastroschisis management was documented, indicating a need for high quality RCTs to provide an evidence-based approach when caring for these infants. TYPE OF STUDY: Qualitative systematic review of Level 1-4 studies.

Who is in Your Waiting Room? Social Determinants of Health and Adverse Childhood Experiences in Pediatric Surgery Clinics.

BACKGROUND: Social determinants of health (SDoH) influence overall health, although little is known about the SDoH for pediatric patients requiring surgical services. This study aims to describe SDoH for pediatric surgical patients attending out-patient, community, and outreach clinics, as well as demonstrate the feasibility of identifying and addressing SDoH and Adverse Childhood Experiences (ACEs) when appropriate. METHODS: A cross-sectional study using surveys evaluating SDoH that were distributed to families attending pediatric surgical clinics over a two-year period. The pilot survey used validated questions and was later refined to a shorter version with questions on: Barriers to care, Economic factors, Adversity, Resiliency and Social capital (BEARS). Data was analyzed with descriptive and inferential statistics. RESULTS: 851 families across 13 clinics participated. One third of families reported not having a primary health care provider or being unable to turn to them for additional support. One in four families were found to have a household income less than the Canadian after-tax low-income threshold (<$40,000 CAD). Two-thirds of families answered questions about ACEs, and those with more ACEs were more likely to report a low income. Forty percent of families rarely or only sometimes had adequate social support. CONCLUSION: This survey tool enabled discussions between families and care providers, which allowed clinicians to appropriately follow-up with families and refer them to social work for further support when indicated. Addressing concerns around SDoH within a busy surgical clinical is feasible and may positively affect long-term health outcomes and equitable resource allocation. LEVEL OF EVIDENCE: IV.