Patel, Robin

Abstract Background Lung transplant recipients (LTRs) can experience hyperammonemia syndrome (HS) correlated with lung infection by ammonia-producing Ureaplasma species. HS in LTRs can be managed by Ureaplasma-directed antibiotic therapy; however, Ureaplasma species lack a cell wall, limiting treatment options. Precise guidelines for Ureaplasma-directed antibiotic therapy in LTRs is lacking, and antibiotic resistance may complicate treatment. Here, levofloxacin (LEV), azithromycin (AZM), and doxycycline (DOX) were tested against isolates of U. urealyticum and U. parvum with varying antibiotic resistance profiles, and efficacies compared.Fig 1.Antibiotic prophylaxis of murine infection by antibiotic resistant Ureaplasma isolates. Mice were prophylaxed with levofloxacin (LEV; 100 mg/kg SQ), azithromycin (AZM; 100 mg/kg PO), or doxycycline (DOX; 100 mg/kg IP) 12 hours prior to infection with isolates of Ureaplasma parvum or Ureaplasma urealyticum resistant to one or none of the antibiotics. 18 hours after infection, mice were sacrificed and lungs harvested, with resulting Ureaplasma loads quantified (color changing units: CCU). Control animals (CTRL) were given no antibiotics. Significance between groups was determined via Kruskal-Wallis tests with Dunn’s multiple comparison tests. * p ≤0.05, **p ≤0.01, ***p ≤0.001. Methods Mice were immunosuppressed using a combination of tacrolimus (1.2 mg/kg daily), mycophenolate mofetil (40 mg/kg daily), and methylprednisolone (20 mg/kg weekly) to mimic immunosuppression given to LTRs. Prophylactic antibiotics were given 12 hours prior to infection, including either LEV (100 mg/kg subcutaneously), AZM (100 mg/kg orally), or DOX (100 mg/kg intraperitoneally). Mice were then infected with Ureaplasma isolates resistant to one or none of the antibiotics, including U. parvum IDRL-10774 (fully susceptible), U parvum IDRL-10774R (IDLR-10774 with evolved AZM resistance; serial passage in sub-MIC AZM), U. parvum IDRL-11160 (LEV resistant), and U. urealyticum ATCC-33175 (DOX resistant). Mice were euthanized 18 hours post-infection, and lung bacterial loads (color changing units; CCU/gram) quantified. Results The effect of various antibiotic treatments against mouse lung infections with the four Ureaplasma isolates is displayed in Fig 1. Infection with IDRL-10774 (fully susceptible) and IDRL-11160 (LEV resistant) was only prevented by doxycycline (p=0.09 and p=0.01, respectively). For IDRL-10774, insignificant mean reductions (possibly due to a high standard deviation in the controls) were observed for both LEV (-106.9 CCU/g) and AZM (-105.25 CCU/g). IDRL-10774R (evolved AZM resistance) showed a complete loss of susceptibility to AZM compared to unevolved IDRL-10774. ATCC-33175 (DOX resistant) was not reduced by any antibiotics tested. Conclusion DOX was the most effective antibiotic tested, preventing lung infection by all isolates, except a DOX resistant isolate. Disclosures Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria

Abstract Background Drug-resistant E. coli is a leading cause of antimicrobial resistance-associated deaths globally. Specifically, resistance to ceftriaxone (CRO-R) is increasing in E. coli. High-risk clonal group ST131 and its pandemic H30 subclone are of high concern yet studies characterizing these infections are limited. We evaluated baseline characteristics and clinical outcomes associated with H30 ST131, non-H30 ST131 and non-ST131 E. coli bloodstream infections (BSI). Methods Patients with monomicrobial carbapenem-susceptible E. coli BSI that were matched 1:1 by study site (CRO-R and CRO-susceptible community-acquired and hospital onset cases) were prospectively enrolled from 14 United States hospitals between November 12, 2020 to April 28, 2021 in the multicenter Study of Highly Resistant E. coli (SHREC). Isolates underwent whole genome sequencing. The primary outcome was a 30-day Desirability of Outcome Ranking (DOOR) after index culture including clinical response to treatment and all-cause mortality. Results There were 92 (33%) H30 ST131, 29 (10%) non-H30 ST131, and 161 (57%) non-ST131 isolates in 282 E. coli BSI (Table 1). Most ceftriaxone resistance was conferred by CTX-M-15 produced by H30 ST131 isolates (Figure 1, Table 1). H30 ST131 BSI patients were older (median age [IQR] 70.5 [63,76] vs. 67 [56,77] vs 65 [51,74] years, p = 0.017), had higher Charlson comorbidity indices (3 [2,5] vs. 2 [1,4] vs. 2 [1,4], p=0.009), and were more often admitted from long-term care facilities (18/92 [20%] vs. 3/29 [10%] vs. 7/161 [4%], p = 0.003) compared to non-H30 ST131 and non-ST131 BSI patients. Among H30 ST131 isolates, high rates of antibiotic resistance were observed to cephalosporins and fluoroquinolones, resulting in significantly more carbapenem use compared with non-H30 ST131 and non-ST131 isolates (75/92 [82%] vs. 14/29 [48%] vs. 50/161 [31%], p < 0.001) (Figure 2). 30-day DOOR and hospital length of stay did not differ between groups (Table 2). Conclusion Compared with non-H30 ST131 and non-ST131 E. coli BSI, H30 ST131 E. coli BSI have a unique epidemiology with more healthcare exposures, comorbidities and antibiotic resistance and are more likely to be treated with carbapenems, though no significant difference in clinical outcomes was observed. Disclosures Yohei Doi, MD, PHD, AbbVie: Honoraria|Entasis: Grant/Research Support|Gilead: Advisor/Consultant|GSK: Advisor/Consultant|Meiji Seika: Advisor/Consultant|Moderna: Advisor/Consultant|Pfizer: Advisor/Consultant|Shionogi: Advisor/Consultant|Shionogi: Honoraria Elie Saade, MD, MPH, FIDSA, Janssen Global Services: Advisor/Consultant|Janssen Global Services: Advisor/Consultant|Janssen Research and Development: Advisor/Consultant|Janssen Research and Development: Advisor/Consultant Loren G. Miller, MD MPH, Armata: Grant/Research Support|Contrafect: Grant/Research Support|GSK: Grant/Research Support|Merck: Grant/Research Support|Paratek: Grant/Research Support Michael J. Satlin, MD, AbbVie: DSMB participant|bioMerieux: Grant/Research Support|Merck: Grant/Research Support|Selux Diagnostics: Grant/Research Support|SNIPRBiome: Grant/Research Support W. Charles Huskins, MD, MSc, ADMA Biologics: Advisor/Consultant|Bristol Myers Squibb: Stocks/Bonds (Public Company)|Pfizer: Advisor/Consultant|Pfizer: Stocks/Bonds (Public Company)|Zimmer Biomet: Stocks/Bonds (Public Company) Carol Hill, PhD, Glaxo SmithKline: Retirement Health, Cash Balance Plan|Glaxo SmithKline: Stocks/Bonds (Public Company) Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria Vance G. Fowler, MD, MHS, Affinergy: Advisor/Consultant|ArcBio: Stocks/Bonds (Private Company)|Armata: Advisor/Consultant|Astra Zeneca: Advisor/Consultant|Astra Zeneca: Grant/Research Support|Basilea: Advisor/Consultant|Basilea: Grant/Research Support|ContraFect: Advisor/Consultant|ContraFect: Grant/Research Support|Debiopharm: Advisor/Consultant|Destiny: Advisor/Consultant|EDE: Grant/Research Support|Genentech: Advisor/Consultant|Genentech: Grant/Research Support|GSK: Advisor/Consultant|Janssen: Advisor/Consultant|Karius: Grant/Research Support|MedImmune: Grant/Research Support|Merck: Grant/Research Support|sepsis diagnostics: Patent pending|UptoDate: Royalties|Valanbuio: Stocks/Bonds (Private Company)|Valanbuio: Stocks/Bonds (Private Company) David van Duin, MD, PhD, Merck: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Advisor/Consultant|Qpex: Advisor/Consultant|Roche: Advisor/Consultant|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support

Abstract Background Morbidity from bacteremia may be exacerbated by inadequate initial antibiotic therapy. This concern however may lead to hesitance to de-escalate while awaiting pathogen identification and susceptibility results. We performed a randomized controlled trial evaluating the impact of a strategy for rapid pathogen and resistance detection directly from positive blood culture bottles (BCBs) using a rapid multiplex PCR (rmPCR) complemented with a rapid phenotypic screen (RPS) for extended-spectrum beta-lactamases and carbapenemases in a setting with moderate to high levels of antimicrobial resistance where routine direct-from-BCB disk diffusion susceptibility testing was in place Methods Patients with positive BCBs were randomized to 2 arms: 1) Standard BCB processing (including direct from BCB disk diffusion susceptibility testing - control, n=419) with antimicrobial stewardship (AS); or 2) rmPCR/RPS with AS (rmPCR/RPS, n=425). The primary outcome was time from positive blood culture result to prescription of an effective or optimal antibiotic regimen. An effective antibiotic regimen was defined as one active against the detected pathogen(s); an optimal antibiotic regimen was defined as an effective regimen which was also the most narrow spectrum and targeted one, as recommended by institutional guidelines. Mortality was analyzed as a secondary outcome. Results True bacteremia was identified in 658 patients (n=329 in both arms); 597 were monomicrobial (405 with aerobic or facultative anaerobic Gram negatives rods [AGNR]) and 61 polymicrobial (41 harboring AGNR). Time from BCB Gram stain to prescription of an effective antibiotic was 9.9 versus 3.2 hours in the control and rmPCR/RPS groups, respectively (p=0.58) and time from Gram stain to prescription of an optimal antibiotic regimen was 41.6 versus 29.4 hours in the two groups, respectively (p < 0.001). 14-day mortality was 7.6% versus 4.3% (p = 0.069) and 30-day mortality was 11.2% versus 8.8% (p=0.30) in the two groups, respectively. Conclusion Compared to control methods which included direct-from-BCB disk diffusion susceptibility testing, an intervention comprising rmPCR/RPS with AS applied to positive blood cultures improved time to optimal therapy but not time to effective therapy or mortality. Disclosures Shawn Vasoo, MBBS, MRCP, D(ABP), D(ABIM) (Inf Dis), FRCPath, bioMerieux: In-kind, for this study|Rosco Diagnostica: In-kind, for this study Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria Paul Tambyah, MBBS (S'pore), Diplomate, American Board of Internal Medicine and Infectious Diseases, Moderna: Grant/Research Support|Sanofi-Pasteur: Grant/Research Support

Fungal infections represent a significant global health challenge. Candida albicans is a particularly widespread pathogen, with both molecular and biofilm-based mechanisms making it resistant to or tolerant of available antifungal drugs. This study reports a combination therapy, active against C. albicans, utilizing terbinafine and essential oils incorporated into a gelatin-based nanoemulsion system (T-GNE). Eugenol and methyl eugenol/terbinafine T-GNEs had an additive efficacy, while carvacrol (CT-GNE) worked synergistically with terbinafine, providing effective antifungal treatment with minimal mammalian cell toxicity. Confocal microscopy demonstrated that CT-GNE penetrated the dense C. albicans biofilm and disrupted the fungal cell membrane. Overall, the combination of essential oils with terbinafine in GNE provided a promising treatment for fungal biofilms.

ABSTRACT In this secondary analysis of 386 subjects with Gram-negative bacteremia enrolled in the RAPIDS GN trial, rapid antibiotic susceptibility testing had a greater benefit on the management of bacteremia caused by antibiotic-resistant compared to antibiotic-susceptible isolates, especially for Escherichia coli, Klebsiella species , and Proteus species. IMPORTANCE Rapid blood culture diagnostics are costly, and their use has not demonstrated clear clinical benefit for patients with Gram-negative sepsis, possibly because prior trials did not enroll sufficient numbers of patients with antibiotic-resistant infections. This analysis of patients with sepsis previously enrolled in a randomized controlled clinical trial demonstrates that rapid susceptibility testing of bacteria from blood cultures had the greatest impact for patients with antibiotic-resistant infections. Specifically, after rapid testing results were reported, patients infected with resistant bacteria received appropriate antibiotic therapy more quickly than patients with susceptible bacteria. These findings highlight the need to evaluate blood culture diagnostics in areas with high antibiotic resistance where these diagnostics are likely to have the greatest impact.

ABSTRACT The definition of the microbiology of pleural space infection has been challenging due to the poor yield of conventional culture. Here, the results of a 16S ribosomal RNA gene PCR/sequencing assay performed on pleural fluid in routine clinical practice between August 2020 and January 2023 were evaluated. Amplified 16S rRNA gene DNA was submitted to Sanger sequencing and/or next-generation sequencing or results were reported as negative, depending on PCR crossing threshold value. In all, 496 pleural fluids were tested at Mayo Clinic Laboratories, with 227 positive results, including 57 from Mayo Clinic patients. Among the 57 Mayo Clinic patients, pleural space infection was community acquired in 48 (84%); Fusobacterium nucleatum group and/or Streptococcus intermedius were detected in 31/57 (54%) cases [including 28/48 (58%) community-acquired cases], with additional facultative and/or anaerobic species also found in various combinations in 17/31 (55%). Results of this study suggest that the most frequent microorganism profile involved in community-acquired pleural space infection may be a combination of F. nucleatum group and/or S. intermedius , with or without other normal microbiota. IMPORTANCE We describe here the most frequent microorganisms detected in community-acquired pleural space infection using a clinically performed sequencing-based assay. We found that the most common detection was the Fusobacterium nucleatum group and/or Streptococcus intermedius , with or without other normal microbiota. We propose the term e-FuSion (effusion with Fusobacterium nucleatum group, Streptococcus intermedius , and other oral normal microbiota) for this entity.

Abstract A cluster of macrolide-resistant Mycoplasma pneumoniae -causing community-acquired pneumonia was observed in children in North Dakota in 2024. Suspicion was raised by non-response to macrolides, with confirmation via a polymerase-chain reaction assay. Prompt improvement occurred after the initiation of alternative antibiotics.

ABSTRACT Ureaplasma species can cause systemic infections in immunocompromised hosts, including lung transplant recipients. Here, we investigated the impact of prior exposure to Ureaplasma urealyticum on the risk of U. urealyticum and Ureaplasma parvum infection in mice subjected to an immunosuppression regimen similar to that administered to solid organ transplant recipients. Mice were immunized with three intramuscular injections of U. urealyticum , with control mice injected with adjuvant only. Following immunization, mice received tacrolimus, mycophenolate mofetil, and methylprednisolone, and then were challenged with U. urealyticum or U. parvum intraperitoneally and intratracheally over 6 days. Relative U. urealyticum antibody levels in plasma were assessed over time, and lungs were harvested at sacrifice for bacterial load quantification, assessed using a color-changing unit assay. U. urealyticum antibody levels were higher in immunized compared with control animals ( P < 0.0001), even when animals were immunosuppressed. U. urealyticum and U. parvum lung burden was reduced in immunized compared with control mice (~6 log 10 reduction for U. urealyticum and <1 log 10 reduction for U. parvum ; P = 0.008 and 0.046, respectively). In summary, this study shows that prior exposure to live U. urealyticum provides some protection against infection with U. urealyticum . IMPORTANCE Ureaplasma -induced hyperammonemia syndrome is a rare but potentially deadly complication of solid organ transplantation, especially lung transplantation. The pathophysiology of this relatively recently recognized condition is poorly understood, and it is unclear what factors may influence patient susceptibility. This study investigates the possible protective effects of prior exposure to Ureaplasma urealyticum in a mouse model subjected to an immunosuppression regimen similar to that given to lung transplant recipients. The findings show that prior exposure could provide protection against Ureaplasma lung infection.

ABSTRACT Ledaborbactam (formerly VNRX-5236), a bicyclic boronate β-lactamase inhibitor with activity against class A, C, and D β-lactamases, is under development as an orally bioavailable etzadroxil prodrug (VNRX-7145) in combination with ceftibuten for the treatment of urinary tract infections. At ceftibuten breakpoints of ≤1 mg/L (EUCAST) and ≤8 mg/L (CLSI), 92.5% and 99.0%, respectively, of 200 carbapenem-resistant Klebsiella pneumoniae isolates, predominantly K. pneumoniae carbapenemase producing, were susceptible to ceftibuten-ledaborbactam (ledaborbactam tested at a fixed concentration of 4 mg/L) compared to 4.5% and 30.5%, respectively, to ceftibuten alone.