Antifungal Susceptibility Testing of <Emphasis Type="Italic">Candida</Emphasis> and <Emphasis Type="Italic">Cryptococcus</Emphasis> Species and Mechanisms of Resistance: Implications for Clinical Laboratories

Purpose of Review

Resistance to antifungal drugs amongst Candida species is a growing concern, and azole resistance may be emerging in Cryptococcus species. This review provides a contemporary perspective, relevant to the clinical mycology laboratory, of antifungal susceptibility testing of these fungi, focussing on the challenges of phenotypic and genotypic methodologies to detect drug resistance.

Recent Findings

Standardised CLSI and EUCAST broth microdilution (BMD) susceptibility testing methods are the benchmark to determine clinical breakpoints (CBPs) and/or epidemiological cut-off values (ECVs) MICs for Candida and Cryptococcus spp. Commercial methods may be used but caution is required when employing BMD CBPs/ECVs to interpret results. Species-specific CBPs/ECVs for Candida spp. generally correlate well with predicting likelihood of therapeutic failure or of presence of a drug resistance mechanism with the exception of the echinocandins where the presence of specific FKS gene mutations and not the MIC correlates most accurately with clinical outcome. The relationship of presence of one or more mechanisms of azole resistance and drug MICs is uncertain. Next generation sequencing technology is offering insights into the relationships between susceptibility results obtained by phenotypic and genotypic methods. For Cryptococcus spp., CBPs are not established but species- and genetic type-specific EVCs are useful for guiding therapy where clinically indicated. Isolates of genotype VGII appear to exhibit the highest MICs.

Summary

Antifungal susceptibility testing of yeasts is important to detect drug resistance. For Candida spp., MICs have clinical utility for the azoles but detecting echinocandin resistance by genotypic methods is preferred. For Cryptococcus spp., ECVs are useful in guiding therapy.

     

Identification of diagnostic biomarkers for infection in premature neonates

Infection is a leading cause of neonatal morbidity and mortality worldwide. Premature neonates are particularly susceptible to infection because of physiologic immaturity, comorbidity, and extraneous medical interventions. Additionally premature infants are at higher risk of progression to sepsis or severe sepsis, adverse outcomes, and antimicrobial toxicity. Currently initial diagnosis is based upon clinical suspicion accompanied by nonspecific clinical signs and is confirmed upon positive microbiologic culture results several days after institution of empiric therapy. There exists a significant need for rapid, objective, in vitro tests for diagnosis of infection in neonates who are experiencing clinical instability. We used immunoassays multiplexed on microarrays to identify differentially expressed serum proteins in clinically infected and non-infected neonates. Immunoassay arrays were effective for measurement of more than 100 cytokines in small volumes of serum available from neonates. Our analyses revealed significant alterations in levels of eight serum proteins in infected neonates that are associated with inflammation, coagulation, and fibrinolysis. Specifically P- and E-selectins, interleukin 2 soluble receptor alpha, interleukin 18, neutrophil elastase, urokinase plasminogen activator and its cognate receptor, and C-reactive protein were observed at statistically significant increased levels. Multivariate classifiers based on combinations of serum analytes exhibited better diagnostic specificity and sensitivity than single analytes. Multiplexed immunoassays of serum cytokines may have clinical utility as an adjunct for rapid diagnosis of infection and differentiation of etiologic agent in neonates with clinical decompensation.     

Use of auditory learning to manage listening problems in children

This paper reviews recent studies that have used adaptive auditory training to address communication problems experienced by some children in their everyday life. It considers the auditory contribution to developmental listening and language problems and the underlying principles of auditory learning that may drive further refinement of auditory learning applications. Following strong claims that language and listening skills in children could be improved by auditory learning, researchers have debated what aspect of training contributed to the improvement and even whether the claimed improvements reflect primarily a retest effect on the skill measures. Key to understanding this research have been more circumscribed studies of the transfer of learning and the use of multiple control groups to examine auditory and non-auditory contributions to the learning. Significant auditory learning can occur during relatively brief periods of training. As children mature, their ability to train improves, but the relation between the duration of training, amount of learning and benefit remains unclear. Individual differences in initial performance and amount of subsequent learning advocate tailoring training to individual learners. The mechanisms of learning remain obscure, especially in children, but it appears that the development of cognitive skills is of at least equal importance to the refinement of sensory processing. Promotion of retention and transfer of learning are major goals for further research.     

No difference in between-country variability in use of newly approved orphan and non- orphan medicinal products - a pilot study

Background

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease, which rapidly leads to chronic respiratory failure requiring mechanical ventilation. Currently, forced vital capacity (FVC) < 50% is considered as physiologic marker for admitting patients to Noninvasive Positive Pressure Ventilation (NPPV) intervention, although it has been recently shown the median survival of patients with baseline FVC < 75% much shorter than median survival of patients with baseline FVC > 75%, independently by any treatment.

Aim

To assess the role of NPPV in improving outcome of ALS, a retrospective analysis was performed to investigate 1 year survival of ALS patients with FVC < 75% and nocturnal respiratory insufficiency, treated with NPPV, compared to a well-matched population of ALS patients, who refused or was intolerant to NPPV.

Methods

We investigated seventy-two consecutive ALS patients who underwent pulmonary function test. Forty-four presented a FVC > 75% and served as control group. Twenty-eight patients presented a FVC < 75% and showed, at polysomnography analysis, nocturnal respiratory insufficiency, requiring NPPV; sixteen were treated with NPPV, while twelve refused or were intolerant.

Results

Increased survival rate at 1 year in patients with FVC < 75% treated with NPPV, as compared to those who refused or could not tolerate NPPV (p = 0.02), was observed. The median rate of decline in FVC% was slower in NPPV patients than in patients who did not use NPPV (95% CI: 0.72 to 1.85; p < 0.0001).

Conclusion

This report demonstrates that early treatment with NPPV prolongs survival and reduces decline of FVC% in ALS.