Time to positivity of blood cultures in a level IV NICU varies based on organism category and population subgroups: is a 36-hour rule out safe?

BACKGROUND: Time to positivity (TTP) of blood cultures and organism characteristics may be different in a Level IV NICU population. METHODS: Retrospective study of 309 Level IV NICU positive blood cultures between January 2012 to December 2018 describing TTP and organism characteristics. RESULTS: Median TTP [IQR] was 21.1 [14.3, 25.2] hours, with 91.2% positive at 36 h, and 96.1% positive at 48 h. Gram negative definite pathogens had the shortest TTP (13.0 [11.4, 15.4] hours) compared to gram positive definite pathogens (16.3 [13.0, 22.4] hours). TTP for treated gram positive commensal organisms (22.3 [20.1, 30.4] hours) and those considered contaminants (23.6 [21.4, 26.0] hours), was significantly longer than both gram positive and negative definite pathogens. CONCLUSION: When antimicrobials are initiated due to concern for bacteremia and blood cultures have not identified a causative pathogen at 36 h, antimicrobials may be safely discontinued in the majority of Level IV NICU patients.

FIVE YEARS OF PARTULA SNAIL PRE-EXPORT HEALTH SCREENING.

Between 2015 and 2019, a health screening was carried out annually on captive-bred Partula snails prior to export for reintroduction as part of an international effort to repopulate areas of French Polynesia, where the snails were extinct or critically endangered. In total, 129 separate tank populations of 12 different species were screened at ZSL London Zoo. Wet mounts and smears stained with modified Ziehl-Neelsen (MZN) of 535 fecal samples were examined, and 45% contained flagellated protozoa, and 35.5% had MZN-positive oocysts, measuring 3-5 µm in diameter. Smaller (2 µm) presumptive spores, MZN-positive bacilli, ciliated protozoa and nematodes were recorded less frequently. Fecal bacterial culture yielded mixed species, with a clear predominance of Myroides species (88.9% of samples). The MZN-positive oocysts (3-5 µm) were present in 6.5% of impression smears from the apices of 432 snails examined postmortem, plus acid-fast bacilli in a few cases, but no 2 µm spores. Mixed bacteria were cultured from coelomic swabs, with Myroides species again the most common (63.5%). Histologic examination was carried out on 292 snails. Autolysis affected almost 90% of those found dead but only 3.4% of euthanized snails. Histology commonly identified microsporidial sporocysts in the digestive gland and midgut epithelium of all but two species. Intracellular, extracytoplasmic Cryptosporidium-like organisms were also common in the midgut but were only observed when snails were fixed in 10% formalin (2017-2019), not ethanol. There were no clear pathologic changes associated with either organism. Pigmented hemocytic nodules were commonly observed, most frequently in the foot process; these were either age related or evidence of prior chronic inflammatory reaction and of low clinical significance. With no evidence of poor health and no significant organisms found, a total of 4,978 individuals representing 12 species were exported for reintroduction.

A Multimodal Intervention to Reduce C. difficile Infections and Stool Testing.

BACKGROUND AND OBJECTIVES: The introduction of multiplex gastrointestinal panels at our institution resulted in increased Clostridioides difficile (C. difficile) detection and stool test utilization. We aimed to reduce hospital-onset C. difficile infections (HO-CDIs), C. difficile detection, and overall stool testing by 20% within 1 year. METHODS: We conducted a quality improvement project from 2018 to 2020 at a large children's hospital. Interventions included development of a C. difficile testing and treatment clinical care pathway, new options for gastrointestinal panel testing with or without C. difficile (results were suppressed if not ordered), clinical decision support tool to restrict testing, and targeted prevention efforts. Outcomes included the rate of HO-CDI (primary), C. difficile detection, and overall stool testing. All measures were evaluated monthly among hospitalized children per 10 000 patient-days (PDs) using statistical process-control charts. For balancing measures, we tracked suppressed C. difficile results that were released during real-time monitoring because of concern for true infection and C. difficile-related adverse events. RESULTS: HO-CDI decreased by 55%, from 11 to 5 per 10 000 PDs. C. difficile detection decreased by 44%, from 18 to 10 per 10 000 PDs, and overall test utilization decreased by 29%, from 99 to 70 per 10 000 PDs. The decrease in stool tests resulted in annual savings of $55 649. Only 2.3% of initially suppressed positive C. difficile results were released, and no patients had adverse events. CONCLUSIONS: Diagnostic stewardship strategies, coupled with an evidence-based clinical care pathway, can be used to decrease C. difficile and improve overall test utilization.

Evidence for overwintering and autochthonous transmission of Usutu virus to wild birds following its redetection in the United Kingdom.

Usutu virus (USUV) is an emerging zoonotic arbovirus in Europe, where it primarily impacts Eurasian blackbirds (Turdus merula). For mosquito-borne viruses to persist in temperate areas, transovarial transmission in vectors or overwintering in either hosts or diapausing vectors must occur to facilitate autochthonous transmission. We undertook surveillance of hosts and vectors in 2021 to elucidate whether USUV had overwintered in the United Kingdom (UK) following its initial detection there in 2020. From 175 dead bird submissions, we detected 1 case of USUV infection, in a blackbird, from which a full USUV genome was derived. Using a molecular clock analysis, we demonstrate that the 2021 detection shared a most recent common ancestor with the 2020 Greater London, UK, USUV sequence. In addition, we identified USUV-specific neutralizing antibodies in 10 out of 86 serum samples taken from captive birds at the index site, demonstrating in situ cryptic infection and potential sustained transmission. However, from 4966 mosquitoes, we detected no USUV RNA suggesting that prevalence in the vector community was absent or low during sampling. Combined, these results suggest that USUV overwintered in the UK, thus providing empirical evidence for the continued northward expansion of this vector-borne viral disease. Currently, our detection indicates geographically restricted virus persistence. Further detections over time will be required to demonstrate long-term establishment. It remains unclear whether the UK, and by extension other high-latitude regions, can support endemic USUV infection.

Impact of Organism Reporting from Endotracheal Aspirate Cultures on Antimicrobial Prescribing Practices in Mechanically Ventilated Pediatric Patients.

Endotracheal aspirate cultures (EACs) help diagnose lower respiratory tract infections in mechanically ventilated patients but are limited by contamination with normal microbiota and variation in laboratory reporting. Increased use of EACs is associated with increased antimicrobial prescribing, but the impact of microbiology reporting on prescribing practices is unclear. This study was a retrospective analysis of EACs from mechanically ventilated patients at Children's Hospital Colorado (CHCO) admitted between 1 January 2019 and 31 December 2019. Chart review was performed to collect all culture and Gram stain components, as well as antibiotic use directed to organisms in culture. Reporting concordance was determined for each organism using American Society for Microbiology guidelines. Days of therapy were calculated for overreported and guideline-concordant organisms. A multivariable model was used to assess the relationship between organism reporting and total days of therapy. Overall, 448 patients with 827 EACs were included in this study. Among patients with tracheostomy, 25 (8%) organisms reported from EACs were overreported and contributed 48 days of excess therapy, while 227 (29%) organisms from the EACs of endotracheally intubated patients were overreported, contributing 472 excess days of therapy. After adjustment, organism overreporting was associated with a >2-fold-higher rate of antimicrobial therapy than guideline-concordant reporting (incident rate ratio [IRR], 2.83; 95% confidence interval [CI], 1.23, 6.53; P < 0.05). Overreported organisms from respiratory cultures contribute to excess antimicrobial therapy exposure in mechanically ventilated patients. Microbiology laboratories have an opportunity to mitigate antimicrobial overuse through standardized reporting practices.

Combining host and vector data informs emergence and potential impact of an Usutu virus outbreak in UK wild birds.

Following the first detection in the United Kingdom of Usutu virus (USUV) in wild birds in 2020, we undertook a multidisciplinary investigation that combined screening host and vector populations with interrogation of national citizen science monitoring datasets to assess the potential for population impacts on avian hosts. Pathological findings from six USUV-positive wild passerines were non-specific, highlighting the need for molecular and immunohistochemical examinations to confirm infection. Mosquito surveillance at the index site identified USUV RNA in Culex pipiens s.l. following the outbreak. Although the Eurasian blackbird (Turdus merula) is most frequently impacted by USUV in Europe, national syndromic surveillance failed to detect any increase in occurrence of clinical signs consistent with USUV infection in this species. Furthermore, there was no increase in recoveries of dead blackbirds marked by the national ringing scheme. However, there was regional clustering of blackbird disease incident reports centred near the index site in 2020 and a contemporaneous marked reduction in the frequency with which blackbirds were recorded in gardens in this area, consistent with a hypothesis of disease-mediated population decline. Combining results from multidisciplinary schemes, as we have done, in real-time offers a model for the detection and impact assessment of future disease emergence events.

Identifying predictors for source culture positivity in children with acute musculoskeletal infections.

OBJECTIVES: Identifying the causative bacterial pathogen for children with acute hematogenous musculoskeletal infections (MSKIs) allows for improved care. The purpose of our study was to determine if clinical markers could predict which patients will have a causative pathogen found on source culture alone, thus being highest yield to undergo operative diagnostic procedures. METHODS: A single-center, retrospective cohort study was performed. Medical records for patients between 6 months and 18 years of age admitted between July 2014 and September 2018 with a discharge diagnosis of acute osteomyelitis, septic arthritis, or pyomyositis were reviewed. Patients were stratified based on results of blood and source cultures. Predictors of interest were screened on a univariable basis with significant predictors retained in a multivariate analysis. RESULTS: There were 170 patients included. No predictors were significantly associated with increased odds of having a causative pathogen found on source culture alone. Degree of C-reactive protein elevation and history of fever were associated with decreased odds of being source culture positive, OR (95% CI); 0.92 (0.87, 0.98) and 0.39 (0.19, 0.81), respectively. CONCLUSIONS: Predictive modeling failed to identify children with MSKIs whose causative pathogen was found by source culture alone. It is difficult to predict which MSKI patients will be highest yield for operative diagnostic procedures.

A Qualitative Risk Assessment for Bluetongue Disease and African Horse Sickness: The Risk of Entry and Exposure at a UK Zoo.

Bluetongue virus (BTV) and African horse sickness virus (AHSV) cause economically important diseases that are currently exotic to the United Kingdom (UK), but have significant potential for introduction and onward transmission. Given the susceptibility of animals kept in zoo collections to vector-borne diseases, a qualitative risk assessment for the introduction of BTV and AHSV to ZSL London Zoo was performed. Risk pathways for each virus were identified and assessed using published literature, animal import data and outputs from epidemiological models. Direct imports of infected animals, as well as wind-borne infected Culicoides, were considered as routes of incursion. The proximity of ongoing disease events in mainland Europe and proven capability of transmission to the UK places ZSL London Zoo at higher risk of BTV release and exposure (estimated as low to medium) than AHSV (estimated as very low to low). The recent long-range expansion of AHSV into Thailand from southern Africa highlights the need for vector competence studies of Palearctic Culicoides for AHSV to assess the risk of transmission in this region.

What's left in the tank? Identification of non-ascribed aquarium's coral collections with DNA barcodes as part of an integrated diagnostic approach.

The unprecedented threats to coral reef ecosystems from global climate change require an urgent response from the aquarium community, which is becoming an increasingly vital coral conservation resource. Unfortunately, many hermatypic corals in aquaria are not identified to species level, which hinders assessment of their conservation significance. Traditional methods of species identification using morphology can be challenging, especially to non-taxonomists. DNA barcoding is an option for species identification of Scleractinian corals, especially when used in concert with morphology-based assessment. This study uses DNA barcodes to try to identify aquarium specimens of the diverse reef-forming genus Acropora from 127 samples. We identified to our best current knowledge, to species name 44% of the analysed samples and provided provisional identification for 80% of them (101/127, in the form of a list of species names with associate confidence values). We highlighted a sampling bias in public nucleotide sequences repertories (e.g. GenBank) towards more charismatic and more studied species, even inside a well-studied genus like Acropora. In addition, we showed a potential "single observer" effect with over a quarter of the reference sequences used for these identifications coming from the same study. We propose the use of barcoding and query matching as an additional tool for taxonomic experts and general aquarists, as an additional tool to increase their chances of making high confidence species-level identifications. We produce a standardised and easily repeatable methodology to increase the capacity of aquariums and other facilities to assess non-ascribed species, emphasising the value of integrating this approach with morphological identification optimising usage of authoritative identification guides and expert opinion. Supplementary Information: The online version contains supplementary material available at 10.1007/s12686-021-01250-3.

Characteristics of Children With Culture Negative Acute Hematogenous Musculoskeletal Infections.

BACKGROUND: Identifying the causative pathogen for acute hematogenous musculoskeletal infections (MSKIs) allows for directed antimicrobial therapy and diagnostic confidence. However, 20% to 50% of children with acute MSKIs remain culture negative. The objective of this study was to compare characteristics of culture negative MSKI patients to those where a pathogen is identified. METHODS: Electronic medical records of children admitted between July 2014 to September 2018 to a single quaternary care pediatric hospital with acute MSKIs were retrospectively reviewed. Clinical and demographic characteristics were compared between culture positive and culture negative MSKIs. RESULTS: A total of 170 patients were included of whom 43 (25%) were culture negative. All culture negative patients had at least 1 culture type obtained, and the majority (84%) had both blood and source cultures performed. When compared with patients with a causative pathogen identified, culture negative patients were younger (2.3 vs. 9.8 y), smaller (13.5 vs. 31.6 kg), less likely to be febrile on arrival (56% vs. 77%), less likely to have an abscess on imaging (23% vs. 48%), and were more likely to have uncomplicated septic arthritis (35% vs. 8%). No critically ill patient was culture negative. Seven culture negative patients had additional Kingella kingae testing performed, none of which were positive. CONCLUSIONS: Despite targeted and standardized efforts to identify causative bacteria, 25% of children with acute MSKIs never have a pathogen identified. Culture negative patients are younger, less febrile, are less likely to have an abscess, and more likely to have isolated septic arthritis. LEVEL OF EVIDENCE: This is a retrospective cohort study interested in identifying patient characteristics that predict rate of culture positivity for acute MSKIs. This study meets criteria for Level II evidence.