Implementation of Semiautomated Antimicrobial Susceptibility Interpretation Hardware for Nontuberculous Mycobacteria May Overestimate Susceptibility

Rapid Electrochemical Detection of Bacterial Sepsis in Cirrhotic Patients: A Microscaffold-Based Approach for Early Intervention

Sepsis is a dysregulated inflammatory response leading to multiple organ failure. Current methods of sepsis detection are time-consuming, involving nonspecific clinical signs, biomarkers, and blood cultures. Hence, efficient and rapid sepsis detection platforms are of utmost need for immediate antibiotic treatment. In the current study, a noninvasive rapid monitoring electrochemical sensing (ECS) platform was developed for the detection and classification of plasma samples of patients with liver cirrhosis by measuring the current peak shifts using the cyclic voltammetry (CV) technique. A total of 61 hospitalized cirrhotic patients with confirmed (culture-positive) or suspected (culture-negative) sepsis were enrolled. The presence of bacteria in the plasma was observed by growth kinetics, and for rapidness, the samples were co-encapsulated in microscaffolds with carbon nanodots that were sensitive enough to detect redox changes occurring due to the change in the pH of the surrounding medium, causing shifts in current peaks in the voltammograms within 2 h. The percentage area under the curve for confirmed infections was 94 and that with suspected cases was 87 in comparison to 69 and 71 with PCT, respectively. Furthermore, the charge was measured for class identification. The charge for LPS-absent bacteria ranged from -400 to -600 μC, whereas the charge for LPS-containing bacteria class ranged from -290 to -300 μC. Thus, the developed cost-effective system was sensitive enough to detect and identify bacterial sepsis.

Nontuberculous mycobacterial lung disease caused by Mycobacterium avium complex - disease burden, unmet needs, and advances in treatment developments

INTRODUCTION

Nontuberculous mycobacterial (NTM) lung disease (LD) is the most common clinical manifestation of NTM infection and is a growing health concern. Up to 85% of NTM-LD cases are caused by Mycobacterium avium complex (MAC). Increased awareness of NTM-LD caused by MAC is needed as patients with this disease experience substantial burden and unmet treatment needs.

AREAS COVERED

This review provides clinicians and regulatory and healthcare decision makers an overview of the clinical, economic, and humanistic burden of NTM-LD and the unmet treatment needs faced by patients and clinicians. The review focuses on NTM-LD caused by MAC. A summary of the 2020 NTM guidelines specifically for MAC-LD and an overview of novel treatment options, including amikacin liposome inhalation suspension (ALIS) as the first approved therapy for refractory MAC-LD, and investigational drugs in testing phase are provided.

EXPERT OPINION

Key advancements in NTM-LD management include recent updates to clinical practice guidelines, approval of ALIS for the treatment of refractory MAC-LD, and ongoing clinical trials of investigational treatments. Yet opportunities still exist to improve patient outcomes, including development of better screening tools, such as reliable and responsive biomarkers to help identify high-risk patients, and addressing unmet treatment needs.

The role of amikacin in the treatment of nontuberculous mycobacterial disease

Introduction: Guidelines recommend the use of amikacin in the treatment of nontuberculous mycobacterial (NTM) disease. The authors have evaluated the evidence for the position of amikacin in NTM disease treatment.Areas covered: The authors performed a literature search for original research on amikacin in NTM disease, including its mechanism of action, emergence of resistance, pre-clinical and clinical investigations.Expert opinion: Amikacin shows moderate in vitro activity against the clinically most relevant NTM species (M. avium complex and M. abscessus). It is synergistic with ethambutol, clofazimine, and macrolides and these combinations are effective in animal models. Liposomal encapsulation increases amikacin efficacy. Clinically, the recommended dose of 15 mg/kg intravenous amikacin does not lead to PK/PD target attainment in all patients and a positive impact on long-term treatment outcomes remains unproven in both M. avium complex and M. abscessus disease. Adding the amikacin liposome inhalation suspension did prove to be effective in short and long term in patients not responding to recommended treatment for M. avium complex pulmonary disease. Its optimal use in M. avium complex and M. abscessus pulmonary disease warrants further evaluation.

Comparative analysis of phenotypic and genotypic antibiotic susceptibility patterns in Mycobacterium avium complex

OBJECTIVE

Phenotypic (Sensititre Myco, pDST) and genotypic drug susceptibility testing (GenoType NTM DR, gDST) in M. avium complex (MAC) have become available as standardized assays, but comparable data is needed. This study aimed to investigate the phenotypic and genotypic drug susceptibility patterns in MAC clinical isolates.

METHODS

Overall, 98 isolates from 85 patients were included. pDST and gDST were performed on all isolates and results compared regarding specificity and sensitivity using pDST as a reference method. The impact of drug instability on pDST results was studied using a biological assay over 14 days. In addition, the evolution of antimicrobial resistance was investigated in sequential isolates of 13 patients.

RESULTS

Macrolide resistance was rare, 1.2% (95% CI 0.7-7.3) of isolates in the base cohort. No aminoglycoside resistances were found, but 14.1% of the studied isolates (95% CI 7.8-23.8) showed intermediate susceptibility. The GenoType NTM DR identified two out of four macrolide-resistant isolates. Antibiotic stability was demonstrated to be poor in rifampicin, rifabutin, and doxycycylin.

CONCLUSIONS

pDST results in NTM for unstable antibiotics must be interpreted with care. A combination of pDST and gDST will be useful for the guidance of antimicrobial therapy in MAC-disease.

Innovative and rapid antimicrobial susceptibility testing systems

Antimicrobial resistance (AMR) is a major threat to human health worldwide, and the rapid detection and quantification of resistance, combined with antimicrobial stewardship, are key interventions to combat the spread and emergence of AMR. Antimicrobial susceptibility testing (AST) systems are the collective set of diagnostic processes that facilitate the phenotypic and genotypic assessment of AMR and antibiotic susceptibility. Over the past 30 years, only a few high-throughput AST methods have been developed and widely implemented. By contrast, several studies have established proof of principle for various innovative AST methods, including both molecular-based and genome-based methods, which await clinical trials and regulatory review. In this Review, we discuss the current state of AST systems in the broadest technical, translational and implementation-related scope.

An Intensified Regimen Containing Linezolid Could Improve Treatment Response in Mycobacterium abscessus Lung Disease

Background

Treatment response for the Mycobacterium abscessus (M. abscessus) lung disease remains far from satisfying. An effective regimen is needed to solve the problem.

Methods

We retrospectively reviewed the medical records of all patients with M. abscessus lung disease who received antibiotics regimen at Beijing Chest Hospital Affiliated to Capital Medical University between July 1, 2010, and February 1, 2018. Patients were administered a conventional antibiotics regimen (including macrolide and moxifloxacin, along with an initial 12-week course of low-dose cefoxitin and amikacin) or intensified regimen (including a higher dosage of cefoxitin and linezolid besides conventional drugs), respectively. The time to sputum-culture conversion and proportion of sputum-culture conversion in liquid broth were investigated to evaluate the efficacy and evaluation of safety by performing the classification of adverse events according to the Division of AIDS, National Institute of Allergy and Infectious Disease. Patients were followed for 18 months from baseline.

Results

In the conventional regimen group, the sputum conversion rate at 18 months was 29.4% (10/34), and the median time until sputum conversion was 2 months (IQR, 1-2 mo). Furthermore, in the intensified regimen group, the sputum conversion rate was 81.3% (13/16), and the median time until sputum conversion was 1 month (IQR, 1-1 mo). Leukopenia and drug-induced hepatotoxicity occurred more frequently in the intensified regimen group in contrast with the conventional regimen group patients. However, only 1 adverse event in the intensified regimen group was classified as severe adverse event.

Conclusions

The intensified regimen could improve sputum conversion of M. abscessus lung disease compared with conventional regimen, but close safety surveillance is necessary to monitor adverse events.