Review of Urinary Tract Infections and Pyelonephritis.

Urinary tract infections (UTIs) are serious bacterial infections affecting children of all ages. An understanding of the methods of urine collection is important to prevent the contamination of urine specimens and to interpret results. The diagnosis of a UTI requires appropriate interpretation of both urinalysis and urine culture results because testing must indicate evidence of inflammation and the presence of bacteria. Rapid treatment of UTIs is imperative to prevent acute decompensation and systemic illness. Empiric antibiotics should be narrowed as soon as possible to tailor antibiotic treatment and limit antibiotic overuse. Imaging with a renal ultrasound scan is recommended for all infants with first febrile UTIs rather than a voiding cystourethrogram. An additional goal of UTI treatment is to prevent renal scarring, which can lead to lifelong health consequences. Children with anatomic abnormalities of the urinary tract and those who have recurrent UTIs are at increased risk of renal scarring. [Pediatr Ann. 2024;53(6):e217-e222.].

Impact of Early Oral Antibiotic Therapy in Infants With Bacteremic Urinary Tract Infections.

OBJECTIVES: To determine the effect of early conversion to oral antibiotics in infants ≤90 days with gram-negative bacteremia and concomitant urinary tract infection on hospital length of stay (LOS) and 30-day revisits for urinary tract infection. DESIGN: This retrospective cohort study included infants ≤ 90 days who had concomitant positive blood and urine cultures with gram-negative bacteremia at 22 hospitals from January 1, 2002 through January 31, 2020. Early oral conversion was defined as a maximum intravenous (IV) duration of 4 days. We conducted a noninferiority test to compare early oral conversion to long IV therapy. A propensity score framework was used to assess comparisons in survey-weighted regression models using matched weights. RESULTS: Among 174 infants, 73 infants received early oral conversion. The LOS was shorter in infants receiving early oral conversion compared to long IV therapy (median 2 days [interquartile range 2, 3] vs 4 days [3, 5]), descriptively (P < .001) and in noninferiority analysis (ratio = 0.43; 90% CI 0.35, 0.53, P < .001). Thirty-day revisits occurred in 5 of 174 (2.8%) of total patients. Early oral conversion did not meet our noninferiority criteria for the 30-day revisits (odds ratio: 4.22, 90%; confidence interval: 0.83, 21.34, P = .91). CONCLUSIONS: Early oral conversion was associated with shorter LOS. The rate of 30-day revisit rates overall was low.

Follow-Up Blood Cultures in Young Infants With Bacteremic Urinary Tract Infections.

BACKGROUND AND OBJECTIVES: Researchers in previous studies suggest that the clinical yield of follow-up blood cultures (FUBCs) is low in infants with bacteremic urinary tract infection (UTI) because persistent bacteremia is rare; however, no researchers have analyzed the practice of routinely obtaining FUBCs. In our study, we evaluate outcomes in infants with FUBCs, examine opportunities for improvement of blood culture practices, and add important information to inform both clinical practice as well as further study. DESIGN: This retrospective cohort study included infants <90 days of age with bacteremia and UTI with the same pathogen at 22 hospitals that make up Intermountain Healthcare between 2002 to 2020. Infants with culture proven meningitis, osteomyelitis, central line infection, and infections occurring during NICU hospitalization were excluded. RESULTS: Total number of patients with bacteremic UTI was 174, 153 (88%) patients had at least 1 FUBC, 14 of 153 (9%) had a positive FUBC with same organism, and 4 of 153 (3%) were contaminants. The length of stay was longer for patients with positive FUBCs. Patients with Escherichia coli are more likely to have a negative FUBC. Readmissions within 30 days were similar among infants with positive FUBCs, negative FUBCs, and no FUBCs. CONCLUSIONS: FUBCs in infants with bacteremic UTI should not be routinely performed, especially for E coli, and it is unclear whether FUBCs improve outcomes.

Implementation of a Weight-Based High-Flow Nasal Cannula Protocol for Children With Bronchiolitis.

OBJECTIVES: To determine if the implementation of a weight-based high-flow nasal cannula (HFNC) protocol for infants with bronchiolitis was associated with improved outcomes, including decreased ICU use. METHODS: We implemented a weight-based HFNC protocol across a tertiary care children's hospital and 2 community hospitals that admit pediatric patients on HFNC. We included all patients who were <2 years old and had a discharge diagnosis of bronchiolitis or viral pneumonia during the preimplementation (November 2013 to April 2018) and postimplementation (November 2018 to April 2020) respiratory seasons. Data were analyzed by using an interrupted time series approach. The primary outcome measure was the proportion of patients treated in the ICU. Patients with a complex chronic condition were excluded. RESULTS: Implementation of the weight-based HFNC protocol was associated with an immediate absolute decrease in ICU use of 4.0%. We also observed a 6.2% per year decrease in the slope of ICU admissions pre- versus postintervention. This was associated with an immediate reduction in median cost per bronchiolitis encounter of $661, a 2.3% immediate absolute reduction in the proportion of patients who received noninvasive ventilation, and a 3.4% immediate absolute reduction in the proportion of patients who received HFNC. CONCLUSIONS: A multicenter, weight-based HFNC protocol was associated with decreased ICU use and noninvasive ventilation use. In hospitals where HFNC is used in non-ICU units, weight-based approaches may lead to improved resource use.

A Novel Presentation of Littoral Cell Angioma and Lymphatic Malformations in a Neonate.

This case report describes a novel presentation of littoral cell angioma (LCA) and lymphatic malformations involving the omentum and mesentery. To our knowledge, these 2 entities have not been reported in the same patient. A 1-month term infant male presented with chylous ascites. During his workup, imaging detected splenic nodules. Biopsies revealed that the nodules were LCA and the chylous ascites was secondary to microscopic mesenteric and omental lymphatic malformations. Evaluation for a secondary malignancy, an underlying immunologic defect, and genetic causes were unrevealing. The presence of LCA and lymphatic malformations in the same patient suggests a genetic link between these 2 rare vascular disorders and may help elucidate the etiopathogenesis of these 2 poorly understood anomalies.

Multiple populations of pantropical spotted dolphins in Hawaiian waters.

Understanding gene flow and dispersal patterns is important for predicting effects of natural events and anthropogenic activities on animal populations. In Hawaii, most species of odontocetes are managed as single populations. Recent exceptions include false killer whales, spinner dolphins, and common bottlenose dolphins, for which studies have shown fidelity to individual islands or groups of islands. Our study focused on pantropical spotted dolphins. We analyzed mitochondrial control region and 11 microsatellite loci from 101 individuals from 4 areas: Hawaii, Maui/Lanai, Oahu, and Kauai/Niihau. We examined F ST, F' ST, R ST, Jost's D, and ΦST and used TESS to estimate number of populations and assignment probabilities. Our results support genetic differentiation among Hawaii, Maui/Lanai, and Oahu and suggest that pantropical spotted dolphins near Kauai/Niihau are likely transient and in low numbers. Between island regions, F ST for microsatellites ranged from 0.016 to 0.045 and for mtDNA, from 0.011 to 0.282. F ' ST, ranged from 0.098 to 0.262 for microsatellites and 0.019 to 0.415 for mtDNA. R ST and ΦST showed similar results to F ST for microsatellites and mtDNA respectively, and Jost's D fell between F ST and F ' ST. TESS supported 3 populations, and greatest mean assignment probability by island region ranged from 0.50 to 0.72. The private alleles method indicated migration rates among regions from 1.49 to 3.45, and effective population size of the island of Hawaii was estimated to be 220. There was no strong evidence to support sex-biased dispersal or group fidelity. Considering this study in the larger context of other odontocete population studies and studies of connectivity, we suggest genetic differentiation may be mediated by behavior adapted to differing habitat types and niches.

Applied conservation genetics and the need for quality control and reporting of genetic data used in fisheries and wildlife management.

Genetic data are often critical for defining populations for management purposes (e.g., identifying geographic boundaries or diagnostic characters for genetically discrete subunits) but can be called into question by both scientific and legal review. This can result in reversed or delayed implementation of management actions. We discuss methods for data quality control and quality analysis and describe examples of steps applied to 2 of the most common types of genetic data, mitochondrial DNA sequences, and microsatellite genotypes. These steps can serve both as guides to conservation geneticists and as an initial protocol for managers to determine whether genetic data will hold up against legal and scientific challenges. In addition, we suggest types of data and quality measures that should be reported as supplementary materials to published reports. These supplementary data serve to reduce the occurrence of legal and conservation controversies and improve reproducibility over time in population genetics studies where genetic monitoring is likely to play an increasing role.

N2 fixation by unicellular bacterioplankton from the Atlantic and Pacific oceans: phylogeny and in situ rates.

N2-fixing proteobacteria (alpha and gamma) and unicellular cyanobacteria are common in both the tropical North Atlantic and Pacific oceans. In near-surface waters proteobacterial nifH transcripts were present during both night and day while unicellular cyanobacterial nifH transcripts were present during the nighttime only, suggesting separation of N2 fixation and photosynthesis by unicellular cyanobacteria. Phylogenetic relationships among unicellular cyanobacteria from both oceans were determined after sequencing of a conserved region of 16S ribosomal DNA (rDNA) of cyanobacteria, and results showed that they clustered together, regardless of the ocean of origin. However, sequencing of nifH transcripts of unicellular cyanobacteria from both oceans showed that they clustered separately. This suggests that unicellular cyanobacteria from the tropical North Atlantic and subtropical North Pacific share a common ancestry (16S rDNA) and that potential unicellular N2 fixers have diverged (nifH). N2 fixation rates for unicellular bacterioplankton (including small cyanobacteria) from both oceans were determined in situ according to the acetylene reduction and 15N2 protocols. The results showed that rates of fixation by bacterioplankton can be almost as high as those of fixation by the colonial N2-fixing marine cyanobacteria Trichodesmium spp. in the tropical North Atlantic but that rates are much lower in the subtropical North Pacific.

Diversity of diazotrophic unicellular cyanobacteria in the tropical North Atlantic Ocean.

We present data on the genetic diversity and phylogenetic affinities of N2-fixing unicellular cyanobacteria in the plankton of the tropical North Atlantic Ocean. Our dinitrogenase gene (nifH) sequences grouped together with a group of cyanobacteria from the subtropical North Pacific; another subtropical North Pacific group was only distantly related. Most of the 16S ribosomal DNA sequences from our tropical North Atlantic samples were closely allied with sequences from a symbiont of the diatom Climacodium frauenfeldianum. These findings suggest a complex pattern of evolutionary and ecological divergence among unicellular cyanobacteria within and between ocean basins.

Genetic evidence on the demography of speciation in allopatric dolphin species.

Under a neutral model, the stochastic lineage sorting that leads to gene monophyly proceeds slowly in large populations. Therefore, in many recent species with large population size, the genome will have mixed support for monophyly unless historical bottlenecks have accelerated coalescence. We use genealogical patterns in mitochondrial DNA and in introns of four nuclear loci to test for historical bottlenecks during the speciation and divergence of two temperate Lagenorhynchus dolphin species isolated by tropical Pacific waters (an antitropical distribution). Despite distinct morphologies, foraging behaviors, and mitochondrial DNAs, these dolphin species are polyphyletic at all four nuclear loci. The abundance of shared polymorphisms between these sister taxa is most consistent with the maintenance of large effective population sizes (5.09 x 10(4) to 10.9 x 10(4)) during 0.74-1.05 million years of divergence. A variety of population size histories are possible, however. We used gene tree coalescent probabilities to explore the rejection region for historical bottlenecks of different intensity given best estimates of effective population size under a strict isolation model of divergence. In L. obliquidens the data are incompatible with a colonization propagule of an effective size of 10 or fewer individuals. Although the ability to reject less extreme historical bottlenecks will require data from additional loci, the intermixed genealogical patterns observed between these dolphin sister species are highly probable only under an extended history of large population size. If similar demographic histories are inferred for other marine antitropical taxa, a parsimonious model for the Pleistocene origin of these distributions would not involve rare breaches of a constant dispersal barrier by small colonization propagules. Instead, a history of large population size in L. obliquidens and L. obscurus contributes to growing biological and environmental evidence that the equatorial barrier became permeable during glacial/interglacial cycles, leading to vicariant isolation of antitropical populations.