Identifying Effective Durations of Antibiotic Therapy for the Treatment of Carbapenem-resistant Enterobacterales Bloodstream Infections: A Multicenter Observational Study.

In a propensity-score-weighted cohort of 183 adults with carbapenem-resistant Enterobacterales bacteremia at 24 US hospitals, patients receiving short courses of active therapy (7-10 days, median 9 days) experienced similar odds of recurrent bacteremia or death within 30 days as those receiving prolonged courses of active therapy (14-21 days, median 14 days).

Challenges in the Treatment of Invasive Aspergillosis in Immunocompromised Children.

Invasive aspergillosis (IA) is associated with significant morbidity and mortality. Voriconazole remains the drug of choice for the treatment of IA in children; however, the complex kinetics of voriconazole in children make dosing challenging and therapeutic drug monitoring (TDM) essential for treatment success. The overarching goal of this review is to discuss the role of voriconazole, posaconazole, isavuconazole, liposomal amphotericin B, echinocandins, and combination antifungal therapy for the treatment of IA in children. We also provide a detailed discussion of antifungal TDM in children.

Challenges with Utilizing the 1,3-Beta-d-Glucan and Galactomannan Assays To Diagnose Invasive Mold Infections in Immunocompromised Children.

Establishing the diagnosis of invasive mold infections (IMI) in immunocompromised children is challenging due to nonspecific clinical presentations and the limited sensitivity of traditional culture-based methods. Rapid non-culture-based diagnostics such as the 1,3-beta-d-glucan and galactomannan assays have emerged as promising adjuncts to conventional diagnostic tests in adults. Available data suggest that 1,3-beta-d-glucan has limited accuracy in the pediatric population and is not recommended to be used for the diagnosis of IMI in children. On the other hand, the diagnostic performance of the serum and bronchoalveolar lavage galactomannan in immunocompromised children is comparable to results observed in adults and can be used as a screening tool in children at high risk of developing invasive aspergillosis (IA) who are not receiving mold-active antifungal prophylaxis and as a diagnostic tool in symptomatic children suspected of having IA. Herein, we summarize the available evidence for the use of these rapid non-culture-based diagnostics in immunocompromised children. We also summarize potential causes of false positivity for the 1,3-beta-d-glucan and galactomannan assays.

Successful Treatment of Persistent Burkholderia cepacia Complex Bacteremia with Ceftazidime-Avibactam.

We report our clinical experience treating a 2-month-old infant with congenital diaphragmatic hernia who experienced prolonged bacteremia with Burkholderia cepacia complex (Bcc) despite conventional antibiotic therapy and appropriate source control measures. The infection resolved after initiation of ceftazidime-avibactam. Whole-genome sequencing revealed that the isolate most closely resembled B. contaminans and identified the mechanism of resistance that likely contributed to clinical cure with this agent. Ceftazidime-avibactam should be considered salvage therapy for Bcc infections if other treatment options have been exhausted.

Protein Kinase Cα (PKCα) Is Resistant to Long Term Desensitization/Down-regulation by Prolonged Diacylglycerol Stimulation.

Sustained activation of PKCα is required for long term physiological responses, such as growth arrest and differentiation. However, studies with pharmacological agonists (e.g. phorbol 12-myristate 13-acetate (PMA)) indicate that prolonged stimulation leads to PKCα desensitization via dephosphorylation and/or degradation. The current study analyzed effects of chronic stimulation with the physiological agonist diacylglycerol. Repeated addition of 1,2-dioctanoyl-sn-glycerol (DiC8) resulted in sustained plasma membrane association of PKCα in a pattern comparable with that induced by PMA. However, although PMA potently down-regulated PKCα, prolonged activation by DiC8 failed to engage known desensitization mechanisms, with the enzyme remaining membrane-associated and able to support sustained downstream signaling. DiC8-activated PKCα did not undergo dephosphorylation, ubiquitination, or internalization, early events in PKCα desensitization. Although DiC8 efficiently down-regulated novel PKCs PKCδ and PKCϵ, differences in Ca(2+) sensitivity and diacylglycerol affinity were excluded as mediators of the selective resistance of PKCα. Roles for Hsp/Hsc70 and Hsp90 were also excluded. PMA, but not DiC8, targeted PKCα to detergent-resistant membranes, and disruption of these domains with cholesterol-binding agents demonstrated a role for differential membrane compartmentalization in selective agonist-induced degradation. Chronic DiC8 treatment failed to desensitize PKCα in several cell types and did not affect PKCßI; thus, conventional PKCs appear generally insensitive to desensitization by sustained diacylglycerol stimulation. Consistent with this conclusion, prolonged (several-day) membrane association/activation of PKCα is seen in self-renewing epithelium of the intestine, cervix, and skin. PKCα deficiency affects gene expression, differentiation, and tumorigenesis in these tissues, highlighting the importance of mechanisms that protect PKCα from desensitization in vivo.

Low-dose Gentamicin for Uncomplicated Enterococcus faecalis Bacteremia May be Nephrotoxic in Children.

BACKGROUND: Uncertainty exists regarding the role of synergistic gentamicin for uncomplicated Enterococcus faecalis bacteremia in children. METHODS: We conducted a retrospective, observational study comparing clinical outcomes of children with E. faecalis bacteremia without endocarditis receiving ampicillin monotherapy with those receiving ampicillin along with low-dose gentamicin therapy. To account for nonrandom assignment of combination therapy, propensity score weighting was combined with multivariable regression to estimate the effect of combination therapy on duration of bacteremia, bacteremic relapse, and acute kidney injury (AKI). RESULTS: One hundred sixty-three (52%) patients received ampicillin with low-dose gentamicin, and 150 (48%) patients received ampicillin monotherapy. Incorporating propensity-score weighting with additional adjustment for source control measures, patients receiving combination therapy experienced bacterial clearance 10 hours faster than children receiving ampicillin monotherapy (adjusted mean difference 0.42; confidence interval (CI), .02 to .82; P = .04). Bacteremic relapse was similar between the two groups (17% vs 18%); adjusted hazards ratio (aHR) 1.12; 95% CI, .65 to 1.92. Children receiving low-dose gentamicin had approximately twice the risk of developing AKI compared to children not receiving this agent, adjusting for the receipt of additional nephrotoxins (aHR 1.94; 95% CI, 1.48-2.97). CONCLUSIONS: Our study suggests that for children with uncomplicated E. faecalis bacteremia, the addition of low-dose gentamicin may decrease the time to bacterial clearance by 10 hours but without any impact on recurrent bacteremia. However, with this potential benefit comes the increased likelihood of AKI. Low-dose gentamicin for the treatment of uncomplicated enterococcal bacteremia may pose harm to children with limited benefit.

Carbapenem therapy is associated with improved survival compared with piperacillin-tazobactam for patients with extended-spectrum ß-lactamase bacteremia.

BACKGROUND: The effectiveness of piperacillin-tazobactam (PTZ) for the treatment of extended-spectrum ß-lactamase (ESBL) bacteremia is controversial. We compared 14-day mortality of PTZ vs carbapenems as empiric therapy in a cohort of patients with ESBL bacteremia who all received definitive therapy with a carbapenem. METHODS: Patients hospitalized between January 2007 and April 2014 with monomicrobial ESBL bacteremia were included. A decrease of >3 doubling dilutions in the minimum inhibitory concentration for third-generation cephalosporins tested in combination with 4 µg/mL of clavulanic acid was used to confirm ESBL status. The primary exposure was empiric therapy, defined as antibiotic therapy administered to a patient before ESBL status was known. Patients were excluded if they did not receive a carbapenem after ESBL production was identified. The primary outcome was time to death from the first day of bacteremia. Propensity scores using inverse probability of exposure weighting (IPW) were used to estimate the probability that a patient would receive PTZ vs carbapenems empirically. We calculated overall hazard ratios for mortality censored at 14 days using Cox proportional hazards models on an IPW-adjusted cohort. RESULTS: A total of 331 unique patients with ESBL bacteremia were identified. One hundred three (48%) patients received PTZ empirically and 110 (52%) received carbapenems empirically. The adjusted risk of death was 1.92 times higher for patients receiving empiric PTZ compared with empiric carbapenem therapy (95% confidence interval, 1.07-3.45). CONCLUSIONS: PTZ appears inferior to carbapenems for the treatment of ESBL bacteremia. For patients at high risk of invasive ESBL infections, early carbapenem therapy should be considered. Our findings should not be extended to ß-lactam/ß-lactamase inhibitor combinations in development, as limited clinical data are available for these agents.

Treatment of multidrug-resistant Gram-negative infections in children.

Antibiotic resistance in conjunction with the erosion of the drug development pipeline may lead us into a bleak future, a "post-antibiotic era." Because of a shortage of studies addressing treatment options for multidrug-resistant Gram-negative (MDRGN) infections in children, data must be extrapolated from the adult literature. However, even adult studies are limited by significant methodological flaws. We are in urgent need of pediatric specific pharmacokinetic/pharmacodynamic data for agents with activity against MDRGN infections as well as improved clinical outcomes studies. For the time being, we must rely on in vitro studies, observational data, and clinical experience to guide our therapeutic decisions. In this review, we discuss treatment considerations for infections caused by extended-spectrum ß-lactamase-producing organisms, AmpC ß-lactamase-producing organisms, carbapenem-resistant Enterobacteriaceae, carbapenem-resistant Pseudomonas aeruginosa, and carbapenem-resistant Acinetobacter baumannii in the pediatric population.

Optimizing therapy for vancomycin-resistant enterococcal bacteremia in children.

PURPOSE OF REVIEW: Uncertainties exist regarding the optimal treatment for vancomycin-resistant enterococcal (VRE) bloodstream infections, particularly in settings in which ampicillin cannot be used. RECENT FINDINGS: Quinupristin-dalfopristin, linezolid, and daptomycin, all approved between 1999 and 2003, represent the mainstays of therapy for VRE bacteremia, although only linezolid has been specifically approved by the United States Food and Drug Administration for this indication. The main objective of this review is to compare the relative efficacies, dosing strategies, and side-effect profiles of quinupristin-dalfopristin, linezolid, and daptomycin for VRE bacteremia in the pediatric population. A brief description of recently approved broad-spectrum Gram-positive agents that may have a role in the management of VRE bacteremia in upcoming years is also provided. SUMMARY: Linezolid, despite its bacteriostatic activity against VRE, may be the most versatile of the available drugs. It has activity against both Enterococcus faecalis and E. faecium, can be administered orally, and resistance appears to be less of a concern with linezolid compared with the other agents. Additionally, the results of two recent meta-analyses demonstrate more favorable outcomes with linezolid compared with daptomycin for the treatment of VRE bacteremia. The clinical pharmacokinetics of linezolid have been well described in children. The most notable concern with linezolid, however, is toxicities associated with prolonged use. Until more prospective data are available, we favor linezolid as first-line therapy for the treatment of VRE bacteremia in children.

Pipeline of Novel Antifungals for Invasive Fungal Disease in Transplant Recipients: A Pediatric Perspective.

Invasive fungal disease (IFD) remains a significant cause of morbidity and mortality in children undergoing transplantation. There is a growing armamentarium of novel antifungal agents recently approved for use or in late stages of clinical development. The overarching goal of this review is to discuss the mechanisms of action, spectrum of activity, stage of development, and pediatric-specific data for the following agents: encochleated amphotericin B deoxycholate, fosmanogepix, ibrexafungerp, isavuconazole, olorofim, opelconazole, oteseconazole, and rezafungin. Additionally, key drug attributes of these novel agents and their potential future therapeutic roles in pediatric transplant recipients are discussed.

MAGENTA: a Multinational patient survey assessing the Awareness, perceptions and unmet needs in GENetic Testing and counselling among patients with breAst cancer.

Objective: Genetic testing and counselling are critical in assessing breast cancer risk and tailoring treatment strategies. However, several barriers hinder patients from opting for genetic testing/counselling, leading to fewer than one-third of patients undergoing testing and even fewer being offered counselling. A granular understanding of these barriers is essential in overcoming them. Methods: A multinational survey developed by patient authors was conducted in 9 countries, to identify the specific local/regional barriers. The survey question pathway was individualized, based on responses to prior questions. Percentage responses to a response option were calculated based on the total number of respondents to that question. Chi-square tests were used to assess the significance of the results, if applicable. Results: The final analysis set (FAS) included 1,176 respondents, with a subset of this responding to all questions. In the FAS, 63% of respondents had undergone testing. Among those who got tested, 70% were offered testing. Among untested respondents, only 40% were offered the test but eventually did not get tested. In the tested population, 44% received counselling, which was significantly higher than 7% (p<0.00001) in the untested group. Among those reporting on awareness, 71% reported awareness level between 'very low' and 'moderate' prior to cancer diagnosis. Most respondents (71%) agreed that all breast cancer patients should undergo testing before treatment initiation. However, Asian patients were less likely to endorse this view compared to respondents from other regions (25% vs ≥50%; p<0.00001). A higher proportion of tested respondents were 'very willing' to get their family members tested (44%) versus untested respondents (11%), with relatively higher willingness among Australian (77%) and Russian respondents (56%), the regional variation being statistically significant (p<0.00001). Conclusions: Critical gaps remain in the access, awareness and perceived value of genetic testing and counselling, with regional variance or difference between the tested and untested groups. Most patients are not offered counselling, which may be associated with the low uptake of testing. Strategic action is needed to drive policy-shaping and improve access to testing and counselling, including raising patient awareness and improving patient experience for better treatment outcomes.

The Clinical Utility of MRSA Nasal Surveillance Swabs in Ruling-Out MRSA Infections in Children.

The utility of methicillin-resistant Staphylococcus aureus (MRSA) nasal surveillance swabs has not been well-described in children. This retrospective, cohort study yielded a negative predictive value of 99.4% for an initial negative MRSA nasal surveillance swab in 165 hospitalized children with a suspected infection and clinical cultures obtained from a likely site of infection.

Boosting of Voriconazole Levels With Omeprazole, A CYP450 2C19 Inhibitor.

Children metabolize voriconazole faster than adults and require higher weight-based doses and more frequent administration to achieve therapeutic troughs. We report a case of a 4-year-old girl with disseminated fusariosis with persistently undetectable voriconazole troughs. Omeprazole was added as a CYP2C19-inhibitor to increase voriconazole concentrations. This case highlights the role of omeprazole for voriconazole boosting in a child.

Successful Treatment of Persistent Stenotrophomonas maltophilia Bacteremia With Cefiderocol in an Infant.

Stenotrophomonas maltophilia is an important nosocomial pathogen with limited treatment options. Trimethoprim-sulfamethoxazole (TMP-SMX) is generally regarded as the preferred therapy; however, treatment failures with TMP-SMX have been reported. Herein, we report a case of a 5-week-old infant with 8 days of S. maltophilia bacteremia while receiving TMP-SMX, despite in vitro susceptibility. Transitioning to cefiderocol monotherapy resulted in blood culture clearance within 24 hours, in the absence of any additional interventions. This is the first published case of the use of cefiderocol for a pediatric patient with an infection due to S. maltophilia. We review preclinical and clinical data that underscore why cefiderocol may be an effective treatment option for S. maltophilia infections.

Technical and clinical outcomes in concurrent multivessel occlusions treated with mechanical thrombectomy: insights from the STAR collaboration.

BACKGROUND: Endovascular thrombectomy (EVT) has become the mainstay treatment for large vessel occlusion, with favorable safety and efficacy profile. However, the safety and efficacy of EVT in concurrent multi-territory occlusions (MTVOs) remains unclear. OBJECTIVE: To investigate the prevalence, clinical and technical outcomes of concurrent EVT for MTVOs. METHODS: Data were included from the Stroke Thrombectomy and Aneurysm Registry (STAR) with 32 stroke centers for EVT performed to treat bilateral anterior or concurrent anterior and posterior circulation occlusions between 2017 and 2021. Patients with MTVO were identified, and propensity score matching was used to compare this group with patients with occlusion in a single arterial territory. RESULTS: Of a total of 7723 patients who underwent EVT for acute ischemic stroke, 54 (0.7%) underwent EVT for MTVOs (mean age 69±12.5; female 50%). 28% had bilateral and 72% had anterior and posterior circulations occlusions. The rate of successful recanalization (Thrombolysis in Cerebral Infarction 2b/3), complications, modified Rankin score at 90 days, and mortality was not significantly different between the matched cohorts. Multivariate analysis confirmed that MTVOs were not associated with poor functional outcome, symptomatic intracranial hemorrhage, or longer procedure time. CONCLUSION: Compared with EVT for single vessel occlusions, EVT in appropriately selected patients with MTVOs has a similar efficacy and safety profile.

Structural and mutational studies of a hyperthermophilic intein from DNA polymerase II of Pyrococcus abyssi.

Protein splicing is a precise self-catalyzed process in which an intein excises itself from a precursor with the concomitant ligation of the flanking polypeptides (exteins). Protein splicing proceeds through a four-step reaction but the catalytic mechanism is not fully understood at the atomic level. We report the solution NMR structures of the hyperthermophilic Pyrococcus abyssi PolII intein, which has a noncanonical C-terminal glutamine instead of an asparagine. The NMR structures were determined to a backbone root mean square deviation of 0.46 Å and a heavy atom root mean square deviation of 0.93 Å. The Pab PolII intein has a common HINT (hedgehog intein) fold but contains an extra ß-hairpin that is unique in the structures of thermophilic inteins. The NMR structures also show that the Pab PolII intein has a long and disordered loop in place of an endonuclease domain. The N-terminal Cys-1 amide is hydrogen bonded to the Thr-90 hydroxyl in the conserved block-B TXXH motif and the Cys-1 thiol forms a hydrogen bond with the block F Ser-166. Mutating Thr-90 to Ala dramatically slows N-terminal cleavage, supporting its pivotal role in promoting the N-S acyl shift. Mutagenesis also showed that Thr-90 and His-93 are synergistic in catalyzing the N-S acyl shift. The block F Ser-166 plays an important role in coordinating the steps of protein splicing. NMR spin relaxation indicates that the Pab PolII intein is significantly more rigid than mesophilic inteins, which may contribute to the higher optimal temperature for protein splicing.

Does the piperacillin minimum inhibitory concentration for Pseudomonas aeruginosa influence clinical outcomes of children with pseudomonal bacteremia?

BACKGROUND: The Clinical and Laboratory Standards Institute (CLSI) recently elected to adjust the previous piperacillin susceptibility breakpoint of ≤64 µg/mL against Pseudomonas aeruginosa to ≤16 µg/mL, based largely on pharmacokinetic-pharmacodynamic (PK-PD) modeling studies. Data on whether PK-PD modeling correlates with clinical outcomes in children are needed before resorting to broader classes of antibiotics to treat P. aeruginosa. METHODS: We performed a retrospective cohort study of children with P. aeruginosa bacteremia between 2001 and 2010 who were prescribed piperacillin. Baseline characteristics and clinical outcomes of children with piperacillin minimum inhibitory concentrations (MICs) of ≤16 µg/mL and of 32-64 µg/mL were compared. The primary outcome was 30-day mortality. RESULTS: There were 170 children with P. aeruginosa bacteremia receiving piperacillin therapy who met inclusion criteria. One hundred twenty-four (72%) children had piperacillin MICs of ≤16 µg/mL and 46 (28%) children had piperacillin MICs of 32-64 µg/mL. There was no significant difference in baseline characteristics between the 2 groups. Thirty-day mortality was 9% and 24% in children with a piperacillin MIC of ≤16 µg/mL and of 32-64 µg/mL, respectively. Using multivariable logistic regression, children with elevated MICs had increased odds of mortality compared with children with lower MICs (odds ratio, 3.21; 95% confidence interval, 1.26-8.16). CONCLUSIONS: Our finding that elevated piperacillin MICs are associated with higher mortality in children supports the recent CLSI recommendation to lower the breakpoint of piperacillin against P. aeruginosa to ≤16 µg/mL. Alternate therapeutic choices should be considered when piperacillin MICs against P. aeruginosa are ≥32 µg/mL.

Letting the little light of mind shine: Advances and future directions in neurochemical detection.

Synaptic transmission via neurochemical release is the fundamental process that integrates and relays encoded information in the brain to regulate physiological function, cognition, and emotion. To unravel the biochemical, biophysical, and computational mechanisms of signal processing, one needs to precisely measure the neurochemical release dynamics with molecular and cell-type specificity and high resolution. Here we reviewed the development of analytical, electrochemical, and fluorescence imaging approaches to detect neurotransmitter and neuromodulator release. We discussed the advantages and practicality in implementation of each technology for ease-of-use, flexibility for multimodal studies, and challenges for future optimization. We hope this review will provide a versatile guide for tool engineering and applications for recording neurochemical release.

Inhibition of angiogenesis and suppression of colorectal cancer metastatic to the liver using the Sleeping Beauty Transposon System.

BACKGROUND: Metastatic colon cancer is one of the leading causes of cancer-related death worldwide, with disease progression and metastatic spread being closely associated with angiogenesis. We investigated whether an antiangiogenic gene transfer approach using the Sleeping Beauty (SB) transposon system could be used to inhibit growth of colorectal tumors metastatic to the liver. RESULTS: Liver CT26 tumor-bearing mice were hydrodynamically injected with different doses of a plasmid containing a transposon encoding an angiostatin-endostatin fusion gene (Statin AE) along with varying amounts of SB transposase-encoding plasmid. Animals that were injected with a low dose (10 µg) of Statin AE transposon plasmid showed a significant decrease in tumor formation only when co-injected with SB transposase-encoding plasmid, while for animals injected with a higher dose (25 µg) of Statin AE transposon, co-injection of SB transposase-encoding plasmid did not significantly affect tumor load. For animals injected with 10 µg Statin AE transposon plasmid, the number of tumor nodules was inversely proportional to the amount of co-injected SB plasmid. Suppression of metastases was further evident in histological analyses, in which untreated animals showed higher levels of tumor cell proliferation and tumor vascularization than animals treated with low dose transposon plasmid. CONCLUSION: These results demonstrate that hepatic colorectal metastases can be reduced using antiangiogenic transposons, and provide evidence for the importance of the transposition process in mediating suppression of these tumors.

The Association of Antibiotic Duration With Successful Treatment of Community-Acquired Pneumonia in Children.

BACKGROUND: National guidelines recommend 10 days of antibiotics for children with community-acquired pneumonia (CAP), acknowledging that the outcomes of children hospitalized with CAP who receive shorter durations of therapy have not been evaluated. METHODS: We conducted a comparative effectiveness study of children aged ≥6 months hospitalized at The Johns Hopkins Hospital who received short-course (5-7 days) vs prolonged-course (8-14 days) antibiotic therapy for uncomplicated CAP between 2012 and 2018 using an inverse probability of treatment weighted propensity score analysis. Inclusion was limited to children with clinical and radiographic criteria consistent with CAP, as adjudicated by 2 infectious diseases physicians. Children with tracheostomies; healthcare-associated, hospital-acquired, or ventilator-associated pneumonia; loculated or moderate to large pleural effusion or pulmonary abscess; intensive care unit stay >48 hours; cystic fibrosis/bronchiectasis; severe immunosuppression; or unusual pathogens were excluded. The primary outcome was treatment failure, a composite of unanticipated emergency department visits, outpatient visits, hospital readmissions, or death (all determined to be likely attributable to bacterial pneumonia) within 30 days after completing antibiotic therapy. RESULTS: Four hundred and thirty-nine patients met eligibility criteria; 168 (38%) patients received short-course therapy (median, 6 days) and 271 (62%) received prolonged-course therapy (median, 10 days). Four percent of children experienced treatment failure, with no differences observed between patients who received short-course vs prolonged-course antibiotic therapy (odds ratio, 0.48; 95% confidence interval, .18-1.30). CONCLUSIONS: A short course of antibiotic therapy (approximately 5 days) does not increase the odds of 30-day treatment failure compared with longer courses for hospitalized children with uncomplicated CAP.