Overview on the Causes and Updated Management of Impetigo

Impetigo is the most common bacterial skin infection in children between the ages of 2 and 5. There are two main types: non-vesicular (70% of cases) and bullous (30% of cases). Non-bullous impetigo or impetigo is caused by Staphylococcus aureus or Streptococcus pyogenes and is characterized by honey-colored skin on the face and limbs. Impetigo primarily affects the skin or is a secondary infection with insect bites, eczema, or herpes lesions. Bullous impetigo caused only by S. aureus causes large, relaxed blisters and is more likely to affect the interstitial area. Both types usually resolve within a few weeks without scarring, and complications are rare, the most serious of which is streptococcal glomerulonephritis. Treatment includes topical antibiotics such as mupirocin, retapamulin, and fusidic acid. Oral antibiotic therapy can be used for impetigo with large blisters, or when topical therapy is not practical. Amoxicillin / clavulanate, dicloxacillin, cephalexin, clindamycin, doxicillin, minocycline, trimetoprim / sulfamethoxazole, and macrolides are optional, but penicillin is not.

Brucella aortitis managed with debridement, extra-anatomical bypass, and long-term antimicrobial therapy

Objectives This report aims to review the management and outcomes of Brucella-associated mycotic aortic aneurysms. Methods This is a retrospective chart review at a tertiary-level healthcare system. IRB approval was waived per policy. Results We describe a case of Brucella aortitis acquired from habitual contact with wild hogs. Clinical presentation included lower back pain and elevated white blood cell count. Diagnosis was confirmed with imaging showing an infrarenal abdominal aortic aneurysm and serology revealing elevated Brucella antibodies titers. The patient was initially managed with endovascular aortic repair and combined oral and intravenous antibiotics therapy. He then underwent explanation and extra-anatomical bypass due to symptomatic periaortic infection and interval development of type I endoleak. The patient was asymptomatic after his final operation at 24 months of follow-up and remained on suppressive oral antibiotic therapy. Conclusions An aortic aneurysm secondary to Brucella is a rare entity. A detailed history of long-term exposure to animals may be a clue to obtain serologic testing. Operative debridement and re-establishing of reliable blood flow combined with long-term antibiotic suppression are the mainstay of treatment.

1042. Safety of Investigational Microbiota-Based Live Biotherapeutic RBX2660 in Individuals with Recurrent Clostridioides difficile Infection: Data from Five Prospective Clinical Studies

Background Microbiota-based treatments have shown promise to reduce recurrence, morbidity, and mortality for recurrent Clostridioides difficile infections (rCDI), but consistent and reliable safety data are needed to support regulatory approvals and broaden patient access. Here we provide cumulative safety data from 5 prospective clinical studies evaluating RBX2660—a standardized, microbiota-based investigational live biotherapeutic—for reducing rCDI. Methods This analysis included three Phase 2 (PUNCH CD, PUNCH CD2, PUNCH CD Open Label) and two Phase 3 trials (PUNCH CD3, PUNCH CD3-OLS ad hoc analysis). Participants were ≥18 years old with documented rCDI who completed standard-of-care oral antibiotic therapy prior to treatment with RBX2660. PUNCH CD3-OLS allowed participants with comorbidities of irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD). Depending on the trial, assigned study treatment was 1 or 2 doses of RBX2660 (or placebo), administered rectally. Participants whose CDI recurred within 8 weeks were eligible for additional RBX2660 treatment. Treatment-emergent adverse events (TEAEs) were recorded for at least 6 months following last study treatment; CD2 and CD Open Label recorded TEAEs for 24 months. Results Among 620 participants who received at least one RBX2660 dose (assigned treatment or after recurrence), 324 (52.3%) received 1, 270 (43.5%) received 2, 14 (2.3%) received 3, and 12 (1.9%) received 4. 83 participants received blinded placebo only. A total of 1980 TEAEs were reported from 432 (69.7%) RBX2660-treated participants, compared to 174 TEAEs in 50 (60.2%) placebo-only treated participants. Most TEAEs were mild or moderate in severity, with diarrhea common in all treatment groups. No potentially life-threatening TEAEs were considered related to RBX2660. Study discontinuation due to TEAEs was minimal (< 1%) with none related to RBX2660. There were no reported infections for which the causative pathogen was traced to RBX2660. Conclusion Across five clinical studies with consistent investigational product, RBX2660 was well-tolerated in rCDI participants. In aggregate, this data provides compelling and consistent safety data for RBX2660. Disclosures Tricia Braun, PharmD, Rebiotix, a Ferring Company (Employee) Beth Guthmueller, AS, Rebiotix Inc, A Ferring Company (Employee) Adam J. Harvey, PhD, Rebiotix, A Ferring Company (Employee)

Cystic fibrosis: a diagnosis in an adolescent

Most patients with cystic fibrosis (CF) develop multisystemic clinical manifestations, the minority having mild or atypical symptoms. We describe an adolescent with chronic cough and purulent rhinorrhoea since the first year of life, with diagnoses of asthma, allergic rhinitis and chronic rhinosinusitis. Under therapy with long-acting bronchodilators, antihistamines, inhaled corticosteroids, antileukotrienes and several courses of empirical oral antibiotic therapy, there was no clinical improvement. There was no reference to gastrointestinal symptoms. Due to clinical worsening, extended investigations were initiated, which revealed Pseudomonas aeruginosa in sputum culture, sweat test with a positive result and heterozygosity for F508del and R334W mutations in genetic study which allowed to confirm the diagnosis of CF. In this case, heterozygosity with a class IV mutation can explain the atypical clinical presentation. It is very important to consider this diagnosis when chronic symptoms persist, despite optimised therapy for other respiratory pathologies and in case of isolation of atypical bacterial agents.

70. Impact of the Accelerate Pheno™ System on Clinical and Antimicrobial Outcomes among Inpatients with Gram-Negative Bacteremia at a 528-bed Community Teaching Hospital

Background Traditional methods in blood culture analysis require 24-72 hours to yield identification (ID) and antimicrobial susceptibility testing (AST) results, which may contribute to the use of empiric broad-spectrum antibiotic therapy. Hence, the primary objective of this study was to determine the impact of rapid blood culture analysis with the Accelerate Pheno™ system (AXDX) on time to antibiotic de-escalation. Methods This was a single center, case-control analysis of adult inpatients with E. coli or Klebsiella spp. bacteremia. Cases were prospectively identified by the antimicrobial stewardship team between August and October 2020 after the implementation of AXDX in July 2020. Subjects were matched to historical controls (July 2018-July 2020) based on age (± 3 years), gender, source of infection, and identified organism. The primary outcome was time to antibiotic de-escalation and time to oral antibiotic therapy from the time of positive blood cultures. Secondary outcomes included hospital length of stay, 30-day mortality, 30-day readmission, and 60-day C. difficile infection. Outcomes were compared using descriptive and inferential statistics. Results Of 33 cases identified, 30 (91%) were matched with historical controls. E. coli bloodstream infection was identified in 24 (80%) subjects while Klebsiella spp. was identified in 6 (20%) subjects. The average age was 66 years (SD ± 19) and there was an even distribution of males and females in both groups. Other demographics were similar between groups. The median time to species identification [14 hours (IQR 13 – 18) vs 34 hours (29 – 39), p< 0.001) and AST [20 hours (19 – 37) vs 45 hours (38 – 51), p< 0.001] from laboratory registration was significantly shorter in cases. The average time to antibiotic de-escalation was 1.7 (±1.2) days for cases compared to 2 (±1.3) days for controls (p=0.460). Median time to oral antibiotic therapy from positive blood cultures was 2.9 (1.8 – 4.7) days for cases and 3.4 (2.5 – 5.1) days for controls (p=0.166). There were no significant differences in the secondary outcomes. Conclusion AXDX did not appear to have a significant impact on time to antibiotic de-escalation and time to oral antibiotic therapy. However, time to organism ID and AST results were significantly shorter in the AXDX cohort. Disclosures All Authors: No reported disclosures

The effect of postoperative oral antibiotic therapy on the incidence of postoperative endophthalmitis after phacoemulsification surgery in dogs: 368 eyes (1997–2010)

Purpose To assess the effectiveness of postoperative administration of oral antibiotics at reducing the incidence of endophthalmitis following phacoemulsification cataract extraction in dogs. Methods Medical records of the University of Tennessee College of Veterinary Medicine were reviewed for cases having undergone phacoemulsification and divided according to whether or not they had received oral antibiotics postoperatively. Records were then evaluated for a diagnosis of endophthalmitis and incidence rates between the group receiving postoperative oral antibiotics and the group not receiving postoperative oral antibiotics were compared. Results A total of 215 patients (368 eyes) were identified by the search. One-hundred twelve patients (197 eyes) were treated with oral antibiotics postoperatively. One-hundred and three patients (171 eyes) were not treated with oral antibiotics postoperatively. Three cases of endophthalmitis were identified, with one in the antibiotic-treated group and two in the non-antibiotic treated group (P > 0.05, Fisher’s exact test). Conclusions The overall incidence of endophthalmitis at the University of Tennessee from 1997–2010 was 0.82%. The rate of post-phacoemulsification endophthalmitis was unaffected by the postoperative administration of oral antibiotics.

Optimizing the Management of Uncomplicated Gram-Negative Bloodstream Infections: Consensus Guidance Using a Modified Delphi Process

Background Guidance on the recommended durations of antibiotic therapy, the use of oral antibiotic therapy, and the need for repeat blood cultures remain incomplete for gram-negative bloodstream infections. We convened a panel of infectious diseases specialists to develop a consensus definition of uncomplicated gram-negative bloodstream infections to assist clinicians with management decisions. Methods Panelists, who were all blinded to the identity of other members of the panel, used a modified Delphi technique to develop a list of statements describing preferred management approaches for uncomplicated gram-negative bloodstream infections. Panelists provided level of agreement and feedback on consensus statements generated and refined them from the first round of open-ended questions through 3 subsequent rounds. Results Thirteen infectious diseases specialists (7 physicians and 6 pharmacists) from across the United States participated in the consensus process. A definition of uncomplicated gram-negative bloodstream infection was developed. Considerations cited by panelists in determining if a bloodstream infection was uncomplicated included host immune status, response to therapy, organism identified, source of the bacteremia, and source control measures. For patients meeting this definition, panelists largely agreed that a duration of therapy of ~7 days, transitioning to oral antibiotic therapy, and forgoing repeat blood cultures, was reasonable. Conclusions In the absence of professional guidelines for the management of uncomplicated gram-negative bloodstream infections, the consensus statements developed by a panel of infectious diseases specialists can provide guidance to practitioners for a common clinical scenario.