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Introduction: Using data from the large and geographically diverse Military Health System (MHS) beneficiary population, we aimed to characterize and update the epidemiology and microbiology of pediatric orbital cellulitis given previous data are limited to small, single-center studies., Materials and Methods: Following institutional review board approval, we performed a retrospective analysis using the Military Health System admissions, microbiology, and pharmacy data between June 2009 and September 2019. Patients less than 22 years of age with radiological confirmation of orbital cellulitis were included. Demographic data, presence of sinusitis, advanced imaging reports, blood and wound culture results with antibiotic susceptibilities, and antibiotic prescriptions were collected. Descriptive statistics were used to summarize demographic characteristics. Imaging findings were grouped by Chandler's stage (CS), an imaging-based measure of the progressive severity of orbital involvement. A Cochran-Armitage trend test was used to evaluate the relationship between CS and likelihood of positive confirmatory culture., Results: There was a male predominance (66.9%) and 55.5% of subjects had comorbid sinusitis. Of the 130 subjects included, 33.8% had one or more positive cultures, 30.8% had a positive wound culture, and 4.6% had a positive blood culture. The most identified organism was coagulase-negative staphylococci (23.3%), followed by Staphylococcus aureus (18.9%), Streptococcus intermedius (17.8%), and strict anaerobes as a group (13.3%). Gram-negative organisms were rare. Twenty-five percent of S. aureus were methicillin-resistant. Clindamycin resistance was identified in 9% of all S. aureus, 50% of coagulase-negative staphylococci, and 25% of S. intermedius. Clindamycin plus ceftriaxone was the most prescribed empiric antibiotic regimen (36.2%). Likelihood of a positive culture significantly increased with advancing CS., Conclusions: Orbital cellulitis occurs most frequently in males with sinusitis. Likelihood of positive wound culture is increased with a more advanced CS. Staphylococcus and Streptococcus spp. and anaerobes are the most identified pathogens in orbital cellulitis, while gram-negative organisms are rare. Empiric antibiotic selection should include an anti-methicillin-resistant S. aureus agent combined with a broad-spectrum beta-lactam and anaerobic coverage., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2024. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Objective: To compare continuous positive airway pressure (CPAP) with nasal cannula (NC) as primary noninvasive respiratory therapy in hypoxic infants for transient tachypnea of the newborn (TTN)., Study Design: Retrospective cohort study of infants born at ≥34 weeks of gestation between January 1, 2015 and December 31, 2018., Result: After adjusting for gestational age and birth weight, the maximum fractional inspired oxygen (FiO 2 ) was significantly lower in the CPAP group with an incidence rate ratio (IRR) of 0.85 (95% CI: 0.76-0.96). Although nonsignificant, the CPAP group needed 32% fewer hours on oxygen with an IRR of 0.68 (95% CI: 0.38-1.22). The duration of respiratory support and the incidence of pneumothorax were similar between both groups., Conclusion: Comparing CPAP with NC as initial noninvasive respiratory therapy for TTN, significantly lower maximum FiO 2 was observed in the infants of CPAP group without increase in the incidence of pneumothorax., (© 2021. The Author(s), under exclusive licence to Springer Nature America, Inc.)

ClpX functions as either an independent chaperone or a component of the ClpXP protease, a conserved intracellular protease that acts as a global regulator in the bacterial cell by degrading regulatory proteins, stress response proteins and rate-limiting enzymes. Previously, we found that loss of clpX in Bacillus anthracis Sterne leads to increased susceptibility to antimicrobial agents that target the cell envelope. The aim of this study was to identify genes within the regulatory network of clpX that contribute to antimicrobial resistance. Using microarray analysis, we found 119 genes that are highly differentially expressed in the ∆clpX mutant, with the majority involved in metabolic, transport or regulatory functions. Several of these differentially expressed genes, including glpF, sigM, mrsA, lrgA and lrgB, are associated with cell wall-active antibiotics in other bacterial species. We focused on lrgA and lrgB, which form the lrgAB operon and are downregulated in ∆clpX, because loss of lrgAB increases autolytic activity and penicillin susceptibility in Staphylococcus aureus. While we observed no changes in autolytic activity in either ∆clpX or ∆lrgAB B. anthracis Sterne, we find that both mutants have increased susceptibility to the antimicrobial peptide LL-37 and daptomycin. However, phenotypes between ∆clpX and ∆lrgAB are not identical as ∆clpX also displays increased susceptibility to penicillin and nisin but ∆lrgAB does not. Therefore, while decreased expression of lrgAB may be partially responsible for the increased antimicrobial susceptibility seen in the ∆clpX mutant, disruption of other pathways must also contribute to this phenotype.

Background: Osteoarthritis (OA) of the centrodistal (CD) and tarsometatarsal (TMT) joints is a common cause of lameness in horses. Intra-articular diagnostic anaesthesia and/or therapeutic injection are relied upon to help diagnose and treat many horses with OA of these joints., Objectives: The objective of this study was to determine the accuracy of arthrocentesis of the CD and TMT joints using a sample population of equine surgeons and surgery residents., Study Design: Randomised experimental study., Methods: Six operators each injected four CD and four TMT joints in 12 sedated horses. The operators were randomly assigned to inject either the left CD and right TMT or the right CD and left TMT on four randomly assigned horses. The joints were injected with a 4 ml solution of contrast medium (2 ml), sterile saline (1.5 ml) and amikacin (0.5 ml). A minimum of two radiographs of each joint was obtained to evaluate the presence of contrast medium within the target joint., Results: The TMT joint was successfully injected in 23/24 joints (96% accuracy). The CD joint was successfully injected in 10/24 joints (42% accuracy). Communication between the TMT and CD joints was visible in 26% of successful TMT injections. Communication between the CD and TMT joints was visible in 20% of successful CD injections., Main Limitations: Despite specific requests to do so, we were unable to standardise the injection technique across all operators., Conclusions: The accuracy of injecting the TMT and CD joints of sedated horses was 96 and 42%, respectively. The CD joint was frequently missed with contrast medium being placed in the periarticular tissues. These data support the clinical impression of the difficulty of injecting the CD joint and suggests that practitioners should utilise ancillary methods, such as radiographs, to ensure proper needle placement., (© 2017 EVJ Ltd.)

Objective: To compare the effects of 2 approaches and 2 injection volumes on diffusion of mepivacaine hydrochloride for local analgesia of the deep branch of the lateral plantar nerve (DBLPN) in horses., Design: Experimental study., Animals: 16 adult horses., Procedures: Either 2 mL (low volume) or 8 mL (high volume) of mepivacaine hydrochloride-iohexol (50:50 mixture) was injected by means of 1 of 2 techniques to produce analgesia of the DBLPN. For technique 1, the needle was inserted 15 mm distal to the head of the fourth metatarsal bone and directed perpendicular to the limb. For technique 2, the needle was inserted 20 mm distal to the head of the fourth metatarsal bone and was directed in a proximodorsal direction. Lateromedial radiographs were obtained before and 5, 15, 30, and 60 minutes after injection. Radiographs were evaluated to determine the proximal and distal extent of diffusion of the contrast solution and presumably anesthetic agent and whether contrast agent appeared to be present in the tarsal sheath or tarsometatarsal joint., Results: A high degree of variability in contrast solution diffusion was noted among injections. High-volume injections diffused significantly further proximally and distally than did low-volume injections. Contrast agent was documented within the tarsal sheath in 5 of 32 (16%) injections and within the tarsometatarsal joint in 2 of 32 (6%) injections. No significant difference was found for risk of inadvertent tarsal sheath or tarsometatarsal joint injection between the 2 techniques or the 2 volumes of anesthetic used. Mepivacaine diffused significantly further distally with technique 1 than with technique 2 but diffused significantly further proximally with technique 2 than with technique 1. For both techniques, diffusion in the distal but not the proximal direction significantly increased over time., Conclusions and Clinical Relevance: Results indicated that the proximal and distal diffusion of the mepivacaine-iohexol solution was quite variable following either DBLPN nerve block technique.