One Size Fits All? Application of Susceptible-Dose-Dependent Breakpoints to Pediatric Patients and Laboratory Reporting

A New Variant of Mutational and Polymorphic Signatures in the ERG11 Gene of Fluconazole-Resistant Candida albicans

Background

Resistance to antifungal drugs for treating Candida infections remains a major concern globally despite the range of medications available. Most of these drugs target key proteins essential to the life cycle of the organism. An enzyme essential for fungal cell membrane integrity, lanosterol 14–α demethylase (CYP51), is encoded by the ERG11 gene in Candida species. This enzyme is the target of azole–based drugs. The organism has, however, devised molecular adaptations to evade the activity of these drugs.

Materials and Methods

Classical methods were employed to characterize clinical isolates sampled from women and dogs of reproductive age. For fluconazole efficacy studies, CLSI guidelines on drug susceptibility testing were used. To understand the susceptibility pattern, various molecular and structural analytic approaches, including sequencing, in silico site-directed mutagenesis, and protein-ligand profiling, were applied to the ERG11 gene and CYP51 protein sequences. Several platforms, comprising Clustal Omega, Pymol plugin manager, Pymol molecular visualizer, Chimera–curated Dynameomics rotamer library, protein–ligand interaction profiler, Charmm36 force field, GROMACS, Geneious, and Mega7, were employed for this analysis.

Results

The following Candida species distribution was obtained: 37.84% C. albicans, 8.12% C. glabrata, 10.81% C. krusei, 5.41% C. tropicalis, and 37.84% of other unidentified Candida species. Two codons in the nucleotide sequence of the wild-type (CTC and CCA) coding for LEU–370 and PRO–375, respectively, were mutated to L370S and P375H in the resistant strain. The mutation stabilized the protein at the expense of the heme moiety. We found that the susceptible isolate from dogs (Can–iso–029/dog) is closely related to the most resistant isolate from humans.

Conclusion

Taken together, our results showed new mutations in the heme-binding pocket of caCYP51 that explain the resistance to fluconazole exhibited by the Candida isolates. So far, the L370S and P375H resistance-linked mutations have not been previously reported.

Setting Antimicrobial Susceptibility Testing Breakpoints: A Primer for Pediatric Infectious Diseases Specialists on the Clinical and Laboratory Standards Institute Approach

Breakpoints are the values used by clinical microbiology laboratories to interpret the results of antimicrobial susceptibility testing (AST) and classify isolates as susceptible or resistant. Whether the breakpoints applied by laboratories accurately predict the likelihood of successful treatment with a particular antimicrobial is an issue of critical importance to quality clinical care. In the United States, the Food and Drug Administration (FDA) sets breakpoints, and globally, breakpoints are also set by 2 standards development organizations, the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST); individual laboratories may choose which breakpoints to implement. Many CLSI breakpoints are recognized by FDA, facilitating their incorporation into widely used commercial AST devices. The CLSI Subcommittee on AST's consensus approach to establishing (and as needed, revising) breakpoints involves integration of currently available microbiological, pharmacokinetic-pharmacodynamic, and clinical data. Here, an overview of the CLSI process for establishing breakpoints is provided.

Knowledge gaps in late-onset neonatal sepsis in preterm neonates: a roadmap for future research

Late-onset neonatal sepsis (LONS) remains an important threat to the health of preterm neonates in the neonatal intensive care unit. Strategies to optimize care for preterm neonates with LONS are likely to improve survival and long-term neurocognitive outcomes. However, many important questions on how to improve the prevention, early detection, and therapy for LONS in preterm neonates remain unanswered. This review identifies important knowledge gaps in the management of LONS and describe possible methods and technologies that can be used to resolve these knowledge gaps. The availability of computational medicine and hypothesis-free-omics approaches give way to building bedside feedback tools to guide clinicians in personalized management of LONS. Despite advances in technology, implementation in clinical practice is largely lacking although such tools would help clinicians to optimize many aspects of the management of LONS. We outline which steps are needed to get possible research findings implemented on the neonatal intensive care unit and provide a roadmap for future research initiatives. IMPACT: This review identifies knowledge gaps in prevention, early detection, antibiotic, and additional therapy of late-onset neonatal sepsis in preterm neonates and provides a roadmap for future research efforts. Research opportunities are addressed, which could provide the means to fill knowledge gaps and the steps that need to be made before possible clinical use. Methods to personalize medicine and technologies feasible for bedside clinical use are described.

Selective Laser Sintering (SLS), a New Chapter in the Production of Solid Oral Forms (SOFs) by 3D Printing

3D printing is a new emerging technology in the pharmaceutical manufacturing landscape. Its potential advantages for personalized medicine have been widely explored and commented on in the literature over recent years. More recently, the selective laser sintering (SLS) technique has been investigated for oral drug-delivery applications. Thus, this article reviews the work that has been conducted on SLS 3D printing for the preparation of solid oral forms (SOFs) from 2017 to 2020 and discusses the opportunities and challenges for this state-of-the-art technology in precision medicine. Overall, the 14 research articles reviewed report the use of SLS printers equipped with a blue diode laser (445-450 nm). The review highlights that the printability of pharmaceutical materials, although an important aspect for understanding the sintering process has only been properly explored in one article. The modulation of the porosity of printed materials appears to be the most interesting outcome of this technology for pharmaceutical applications. Generally, SLS shows great potential to improve compliance within fragile populations. The inclusion of "Quality by Design" tools in studies could facilitate the deployment of SLS in clinical practice, particularly where Good Manufacturing Practices (GMPs) for 3D-printing processes do not currently exist. Nevertheless, drug stability and powder recycling remain particularly challenging in SLS. These hurdles could be overcome by collaboration between pharmaceutical industries and compounding pharmacies.

Best practice: antibiotic decision-making in ICUs

PURPOSE OF REVIEW

A major challenge in the ICU is optimization of antibiotic use. This review assesses current understanding of core best practices supporting and promoting astute antibiotic decision-making.

RECENT FINDINGS

Limiting exposure to the shortest effective duration is the cornerstone of antibiotic decision-making. The decision to initiate antibiotics should include assessment of risk for resistance. This requires synthesis of patient-level data and environmental factors to determine whether delayed initiation could be considered in some patients with suspected sepsis until sensitivity data is available. Until improved stratification scores and clinically meaningful cut-off values to identify MDR are available and externally validated, decisions as to which empiric antibiotic is used should rely on syndromic antibiograms and institutional guidance. Optimization of initial and maintenance doses is another enabler of enhanced outcome. Stewardship practices must be streamlined by re-assessment to minimize negative effects, such as a potential increase in duration of therapy and increased risk of collateral damage from exposure to multiple, sequential antibiotics that may ensue from de-escalation.

SUMMARY

Multiple challenges and research priorities for antibiotic optimization remain; however, the best stewardship practices should be identified and entrenched in daily practice. Reducing unnecessary exposure remains a vital strategy to limit resistance development.

Advancing pediatric antimicrobial stewardship: Has pharmacodynamic dosing for gram-negative infections taken effect?

Objective:

To characterize pharmacodynamic dosing strategies used at children’s hospitals using a national survey.

Design:

Survey.

Setting:

Children’s hospitals.

Participants:

Volunteer sample of antimicrobial stewardship program (ASP) respondents.

Methods:

A nationwide survey was conducted to gain greater insight into the current adoption of nontraditional dosing methods and monitoring of select β-lactam and fluoroquinolone antibiotics used to treat serious gram-negative infections in pediatric populations. The survey was performed through the Sharing Antimicrobial Reports for Pediatric Stewardship (SHARPS) Collaborative.

Results:

Of the 75 children’s hospitals that responded, 68% of programs reported adoption of pharmacodynamically optimized dosing using prolonged β-lactam infusions and 35% using continuous β-lactam infusions, although use was infrequent. Factors including routine MIC monitoring and formal postgraduate training and board certification of ASP pharmacists were associated with increased utilization of pharmacodynamic dosing. In addition, 60% of programs reported using pharmacodynamically optimized ciprofloxacin and 14% reported using pharmacodynamically optimized levofloxacin. Only 20% of programs monitored β-lactam levels; they commonly cited lack of published guidance, practitioner experience, and laboratomory support as reasons for lack of utilization. Less physician time dedicated to ASP programs was associated with lower adoption of optimized dosing.

Conclusions:

Use of pharmacodynamic dosing through prolonged and continuous infusions of β-lactams have not yet been routinely adopted at children’s hospitals. Further guidance from trials and literature are needed to continue to guide pediatric pharmacodynamic dosing efforts. Children’s hospitals should utilize these data to compare practices and to prioritize further research and education efforts.