Monitoring Of Drug Resistance Research Articles

Multifunctional liposomal complex for detection of the acquired resistance to EGFR-TKIs and synergistic anticancer phototherapy

The emergence of acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) poses formidable obstacles to non-small cell lung cancer (NSCLC) therapy. Real-time monitoring of the efficacy of EGFR-TKIs to avoid invalid treatment remains a great challenge. Herein, we rationally designed a EGFR-TKI-modified liposomal complex co-loaded with a iodine-containing contrast agent ioversol (IOV) and a photosensitizer indocyanine green (ICG), namely ELIG, for simultaneous EGFR-TKI-mediated computed tomography/fluorescence dual-modal imaging to monitor drug resistance during the treatment, and combined photodynamic therapy (PDT) and photothermal therapy (PTT) to reverse drug resistance. ELIG exhibited good physicochemical properties, favorable photothermal effects, and high singlet oxygen production. ELIG can protect ICG and IOV from rapid degradation and prolong the circulation time. In addition, ELIG had a great ability to recognize drug-sensitive EGFR-mutated NSCLC cells, and could monitor the changes in the intracellular amounts of the imaging agents to detect the drug resistance and predict the efficacy during the treatments. Additionally, the heavy atom effect of IOV can increase the PDT effect of ICG obviously. With 808 nm laser irradiation, ELIG showed satisfactory anticancer effects to reverse drug resistance by the synergism of PDT and PTT in vitro and in vivo. Hence, this work holds great promise for providing a new idea and an effective strategy for predicting and managing the efficacy of EGFR-TKIs.

An enzymatically activated self-powered and self-recycled strategy for in situ tumor cell-specific molecular imaging

Specific imaging of tumor cells with high sensitivity is urgently needed for evaluating the risk of tumor metastasis and progression. However, traditional tumor cell imaging strategies are still restricted by limited tumor specificity and sensitivity due to off-tumor signal leakage and a lower content of the targets. Therefore, a self-powered and self-recycled strategy based on molecular beacon (MB) hybridized on tetrahedral framework DNA (E-MB-tFNA) using the endogenous enzyme, apurinic/apyrimidinic endonuclease 1 (APE1), was rationally developed for tumor cell-specific molecular imaging with superior spatial specificity and improved sensitivity. The apurinic/apyrimidinic site (AP site) can be specifically recognized and cleaved by APE1, and was modified on the stem and loop region of E-MB-tFNA. The resultant E-MB-tFNA can be specifically recognized and cleaved by APE1 in the cytoplasm, which is overexpressed in tumor cells compared to normal cells. In particular, once APE1 cleaves the AP site on the stem region (double-stranded DNA) of E-MB-tFNA, the self-powered and self-recycled sequences modified on the stem region of E-MB-tFNA is freed to hybridize with the loop region of E-MB-tFNA, prompting APE1 to further hydrolyze the E-MB-tFNA loop region and generate fluorescence signals. In addition, the self-powered and self-recycled sequences can be hybridized with other E-MB-tFNA to continuously and cyclically amplify the fluorescence signal. The experimental results of this study showed that the E-MB-tFNA has the capability to monitor drug resistance and achieve guided precision surgical excision in vivo with superior spatial specificity and improved sensitivity. In particular, E-MB-tFNA can realize the risk classification of neuroblastoma patients in clinical plasma.

Comparison of targeted next-generation sequencing and the Xpert MTB/RIF assay for detection of Mycobacterium tuberculosis in clinical isolates and sputum specimens.

Targeted next-generation sequencing (tNGS) can be used to perform Mycobacterium tuberculosis (MTB) complex-specific amplification or target capture directly from sputum samples, yielding simultaneous coverage of many genes and DNA regions associated with antimicrobial resistance (AMR). Performance comparisons of tNGS and another molecular testing tool, Xpert MTB/rifampicin (RIF), have been empirical. Here, using a dilution series of a RIF-resistant clinical isolate of MTB, we found that tNGS had a slightly lower limit of bacterial detection (102 CFU/mL) compared with Xpert MTB/RIF (103 CFU/mL) in culture medium. However, the minimum detection limit of the rpoB S450L mutation in this isolate was significantly lower with tNGS (102 CFU/mL) than with Xpert MTB/RIF (106 CFU/mL). Sputum samples collected from 129 suspected pulmonary tuberculosis patients were also prospectively studied with the clinical diagnosis as a reference, revealing that the sensitivity of tNGS (48.6%) was higher than those of culture (46.8%), Xpert MTB/RIF (39.4%), and smear microscopy (34.9%) testing. Notably, AMR analysis of 56 MTB-positive samples as determined by tNGS revealed high mutation frequencies of 96.4%, 35.7%, 26.8%, and 19.6% in the following AMR-associated genes: rrs, rpoB, katG, and pncA, respectively. The findings of this study provide theoretical support for the differential clinical application of tNGS and Xpert MTB/RIF and suggest that tNGS has greater application value in tuberculosis drug resistance monitoring and prevention.IMPORTANCETargeted next-generation sequencing (tNGS) can be used to perform Mycobacterium tuberculosis (MTB) complex-specific amplification or target capture directly from sputum samples, yielding simultaneous coverage of genes and DNA regions associated with antimicrobial resistance (AMR). Performance comparisons of tNGS and Xpert MTB/rifampicin (RIF) have been empirical. The Xpert MTB/RIF assay is a commercial system that uses the nucleic acid amplification detection method for rapid (2 hours) diagnosis of tuberculosis (TB). The cost of the tNGS and Xpert MTB/RIF assays in this study was similar, at USD 98 and USD 70-104 per sample, respectively, but the time required for tNGS (3 days) was much longer than that required for the Xpert MTB/RIF assay. However, tNGS yielded more accurate results and a larger number of AMR-associated gene mutations, which compensated for the extra time and highlighted the greater application value of tNGS in TB drug resistance monitoring and prevention.

Genotypic Characterization of Mycobacterium Tuberculosis Strains Resistant to Rifampicin, Isoniazid and Second-Line Antibiotics in Chad

Monitoring drug resistance and identifying the genetic basis of resistance to first- and second-line anti-tuberculosis (anti-TB) drugs provides important information to optimize patient care. The present study was an observational, cross-sectional and analytical study aimed at determining the prevalence of resistance genes to rifampicin, isoniazid and resistant and multi-resistant genes with mutations associated with second-line anti-tuberculosis drugs (Levofloxacin Amikacin, Kanamycin and Capreomycin) among strains of Mycobacterium tuberculosis in nine hospitals in four provinces of Chad with three new molecular techniques. The TB-LAMP molecular technique made it possible to detect 264 (25.14%) strains of Mycobacterium tuberculosis complex among 1050 people referred for tuberculosis research, including 37 cases in relapse and 237 new cases under treatment or not without clinical improvement. The average age of the patients was 34.15 years with the extremes ranging from 12 to 77 years. The sex ratio was 3.33 in favor of men. The GeneXpert made it possible to confirm the 264 positive cases of Mycobacterium tuberculosis (MTB+) of which 76% of men and 24% of women had the MTB+ profile sensitive to rifampicin, and 80% of men and 20% of women harbored the Mycobacterium complex. rifampicin-resistant tuberculosis. The determination of resistance genes including 13% (rpoB) to rifampicin, 4% (inhA) to isoniazid and 8% (rpoB/KatG and/or KatG/inhA) multi-resistant (MDR) genes was carried out using the Line Probe Assay technique. This technique also made it possible to determine resistance genes with associated mutations including 13.6% (gyrA and gyrB), 7.6% (eis), 6.1% (rrs and eis) and 10.6% being mutations affecting the different alleles on the chromosomes of the Mycobacterium tuberculosis complex. This study highlighted the emergence of resistance to rifampicin and isoniazid as well as resistance with mutations associated with second-line anti-tuberculosis drugs. It raises the need to implement an effective surveillance system to detect the resistance of Mycobacterium tuberculosis to anti-tuberculosis drugs in Chad and even in Central Africa.

Next Generation Chemiluminescent Probes for Antimalarial Drug Discovery.

Malaria is caused by parasites of the Plasmodium genus and remains one of the most pressing human health problems. The spread of parasites resistant to or partially resistant to single or multiple drugs, including frontline antimalarial artemisinin and its derivatives, poses a serious threat to current and future malaria control efforts. In vitro drug assays are important for identifying new antimalarial compounds and monitoring drug resistance. Due to its robustness and ease of use, the [3H]-hypoxanthine incorporation assay is still considered a gold standard and is widely applied, despite limited sensitivity and the dependence on radioactive material. Here, we present a first-of-its-kind chemiluminescence-based antimalarial drug screening assay. The effect of compounds on P. falciparum is monitored by using a dioxetane-based substrate (AquaSpark β-D-galactoside) that emits high-intensity luminescence upon removal of a protective group (β-D-galactoside) by a transgenic β-galactosidase reporter enzyme. This biosensor enables highly sensitive, robust, and cost-effective detection of asexual, intraerythrocytic P. falciparum parasites without the need for parasite enrichment, washing, or purification steps. We are convinced that the ultralow detection limit of less than 100 parasites of the presented biosensor system will become instrumental in malaria research, including but not limited to drug screening.

Clinical distribution of carbapenem genotypes and resistance to ceftazidime-avibactam in Enterobacteriaceae bacteria.

Bacterial resistance is a major threat to public health worldwide. To gain an understanding of the clinical infection distribution, drug resistance information, and genotype of CRE in Dongguan, China, as well as the resistance of relevant genotypes to CAZ-AVI, this research aims to improve drug resistance monitoring information in Dongguan and provide a reliable basis for the clinical control and treatment of CRE infection. VITEK-2 Compact automatic analyzer was utilized to identify 516 strains of CRE collected from January 2017 to June 2023. To determine drug sensitivity, the K-B method, E-test, and MIC methods were used. From June 2022 to June 2023, 80 CRE strains were selected, and GeneXpert Carba-R was used to detect and identify the genotype of the carbapenemase present in the collected CRE strains. An in-depth analysis was conducted on the CAZ-AVI in vitro drug sensitivity activity of various genotypes of CRE, and the results were statistically evaluated using SPSS 23.0 and WHONET 5.6 software. This study identified 516 CRE strains, with the majority (70.16%) being K.pneumoniae, followed by E.coli (18.99%). Respiratory specimens had highest detection rate with 53.77% identified, whereas urine specimens had the second highest detection rate with 17.99%. From June 2022 to June 2023, 95% of the strains tested using the CRE GeneXpert Carba-R assay possessed carbapenemase genes, of which 32.5% were blaNDM strains and 61.25% blaKPC strains. The results showed that CRE strains containing blaKPC had a significantly higher rate of resistance to amikacin, cefepime, and aztreonam than those harboring blaNDM. The CRE strains isolated from Dongguan region demonstrated a high resistance rate to various antibiotics used in clinical practice but a low resistance rate to tigecycline. These strains produce Class A serine carbapenemases and Class B metals β-lactamases, with the majority of them carrying blaNDM and blaKPC. Notably, CRE strains with blaKPC and blaNDM had significantly lower resistance rates to tigecycline. CAZ-AVI showed a good sensitivity rate with no resistance to CRE strains carrying blaKPC. Therefore, CAZ-AVI and tigecycline should be used as a guide for rational use of antibiotics in clinical practice to effectively treat CRE.

Epidemiologic analysis of antimicrobial resistance in hospital departments in China from 2022 to 2023

Bacterial drug resistance monitoring in hospitals is a crucial aspect of healthcare management and a growing concern worldwide. In this study, we analysed the bacterial drug resistance surveillance in our hospital from 2022 Q1 to 2023 Q2. The main sampling sources were respiratory, blood, and urine-based, and the main clinical infections were respiratory and genitourinary in nature. Specimens were inoculated and cultured; bacterial strains were isolated using a VITEK® 2 Compact 60-card automatic microorganism identifier (bioMerieux, Paris, France) and their matching identification cards were identified, and manual tests were supplemented for strain identification. The most common Gram-positive bacteria detected were Staphylococcus aureus, followed by Enterococcus faecalis (E. faecalis), Staphylococcus epidermidis (S. epidermidis), and Staphylococcus haemolyticus (S. haemolyticus). The most common Gram-negative bacteria detected were Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The most prevalent multidrug-resistant bacteria were those producing extended-spectrum beta-lactamases, followed by methicillin-resistant Staphylococcus aureus, followed by carbapenem-resistant Enterobacterales. This study suggests that the prevention and control of infections in the respiratory and genitourinary systems should be the focus of anti-infective work and that the use of antimicrobials should be reduced and regulated to prevent the emergence and spread of resistant bacteria.

HIV-1 drug resistance and genetic diversity in people with HIV-1 in Cape Verde, 2019-2021.

To characterize the genetic diversity and drug resistance profiles of people with HIV-1 failing ART in Cape Verde (CV). Cross- sectional study conducted between January 2019 and December 2021 in 24 health centres on the islands of Santiago and São Vicente. The HIV-1 pol gene was sequenced in individuals with a detectable viral load (VL). HIV-1 genetic diversity was determined by phylogenetic analysis. Drug resistance mutation patterns and resistance phenotypes were estimated using the Stanford algorithm. VL was detected in 73 of 252 (29%) enrolled participants and sequencing data were produced for 58 (79%) participants. CRF02_AG strains predominated (46.5%), followed by subtype G (22.4%). Most patients (80%) had mutations conferring resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs) (67%), nucleoside reverse transcriptase inhibitors (55%), integrase inhibitors (10%) and/or protease inhibitors (7%) used in CV, a significant increase compared to a study conducted in 2010-2011. The most common mutations were M184 V/I (43%), K103N/S (36%) and G190A/S (19%). NNRTI resistance was associated with younger age and exposure to two or more drug regimens. The HIV-1 epidemic in Cape Verde is mainly driven by CRF02_AG and subtype G. Resistance to NNRTIs and/or NRTIs is highly prevalent and resistance to LPV/r and DTG is emerging. Our results support the use of DTG-based first-line ART and PI-based regimens for patients with virological failure, but emerging resistance to LPV/r and DTG is a concern. Continued monitoring of drug resistance is essential to ensure adequate health care for PLWH in Cape Verde.

Development and application of an ultra-sensitive ctDNA mutation profiling assay in monitoring therapy response and drug resistance.

264 Background: Next-generation sequencing (NGS) assays offer efficient high-throughput profiling methods for analyzing circulating tumor DNA (ctDNA) in blood or other liquid biopsy specimens. The ctDNA mutant allele fractions of patients after treatment is often very low and below the detection limit of regular cfDNA assays. Here we report the development and clinical application of a CLIA-certified ultra-sensitive NGS cfDNA assay in detecting the low-frequency ctDNA mutations and monitoring therapy response and drug resistance in patients with metastatic gastroesophageal adenocarcinoma under combined blockade treatments. Methods: PredicineCARE ULTRA cfDNA assay with 100,000X sequencing depth was validated under CLIA settings. Limit of blank (LoB) and limit of detection (LoD) were established by profiling 38 healthy donor plasma samples, 23 contrived human cfDNAs samples from patients with various cancers, and 30 replicates of well-established ctDNA reference standards. In silico down-sampling of FASTQ files was carried out to test the sensitivity of this assay with a lower coverage (50,000X). This assay was then adopted for longitudinal sequencing of 57 serial plasmas from 6 patients with HER2+ gastroesophageal adenocarcinomas (GEC) who underwent combined treatments (capecitabine, oxaliplatin, bevacizumab and trastuzumab) at different time points (baseline, response, and progression). Results: PredicineCARE ULTRA cfDNA assay exhibited exceptional sensitivity in calling single-nucleotide variants and indels, with a 98.0% detection rate at a LoD of 0.075% mutant allele frequency (MAF) for 60 ng cfDNA. This is significantly lower than the LoD (0.25% MAF) of a standard PredicineCARE cfDNA assay. The ultra-sensitive assay also displayed decent analytical specificity (>99.99%) and precision (intra-assay 100%; inter-assay 99.41%). In 6 GEC patients’ longitudinal samples, PredicineCARE ULTRA cfDNA assay detected 36 additional somatic mutations with the MAFs spanning in a range from 0.024% to 0.1% beyond 124 baseline mutations identified using standard PredicineCARE. In two representative cases presented here, all baseline mutations (genes TP53 and PIK3CA etc.) were consistently reported in the follow-up time points with a noticeable MAF reduction (lowest MAFs from 0.046% to 0.024%) during response. Subsequent elevations were observed in more genes, including low-frequency mutations (KRAS and ERBB2) not detected at baseline or only detected in PredicineCARE ULTRA. Conclusions: This study demonstrated the promise and clinical utility of the ultra-sensitive cfDNA molecular profiling at 100,000X sequencing depth in treatment selection, therapy monitoring, and drug resistance studies.

Abstract B111: Developing prognostic signatures (ep-Sigs) through epigenetic predictive markers in pancreatic ductal adenocarcinoma (PDA) – A pilot study based on The Cancer Genome Atlas (TCGA) data

Abstract Current genomic testing (mutation profiling) has not proven beneficial for optimal treatment selection or for monitoring drug resistance, which is critical for neoadjuvant therapy (NAT) in borderline resectable/resectable PDA and first-line therapy for advanced PDA. Failure to administer an effective chemotherapy combination results in early progression of the disease, life-threatening complications, and a decline in the patient’s performance status, rendering them ineligible for further anti-cancer treatment. We hypothesized that our panel of epigenetic markers (DNA-methylation changes) is a surrogate for protein/gene expression and will develop an ep-Sigs that also has predictive value. The genes in this panel have been curated from extant literature and belong to one of two broad categories: one with known prognostic value (PvG) and the other with preclinical or clinical evidence of influencing one of the drugs (DrG) used in PDA management (gemcitabine (gem), 5-fluorouracil (5FU), oxaliplatin (Ox), irinotecan (Iri), nab-paclitaxel (NP), paclitaxel (Tax), and cisplatin (Cis)). Some genes/proteins were critical for more than one drug. To accomplish this, we tested the panel in the TCGA pancreatic adenocarcinoma (PAAD) data with 182 patients. For univariate survival analysis (UVA), we used Cox regression models for each marker. For multivariate survival analysis (MVA), we used penalized Cox regression models (i.e., LASSO, Elastic-Net) for identifying marker signatures. The area under the ROC Curve (AUC) was calculated to assess each signature’s predictive performance. We identified 301 cytosines followed by guanine residue (CpG) sites among the 67 genes (gem=35, 5FU=13, 5FU+gem=10, NP=6, Cis=6, and PvG=23) in the panel with significant (p<0.05) association with overall survival (OS) through UVA. We identified five ep-Sigs through MVA that could predict poor OS (p<0.05), which are a combination of markers from PvG and DrG. The number of markers and relevant DrG in them are as follows, 15 & Gem/Cis; 30 & Gem/5FU/Cis/Tax/Iri; 28 & Gem/5FU/NP/Cis/Tax/Iri; 23 & Gem/5FU; 29 & Gem/5FU/NP. We did a similar analysis for RNA-sequencing data from TCGA. We identified 17 markers and 9 signatures on UVA and MVA, respectively. Interestingly, the expression of 100/105 markers in the panel was significantly (p=4.19e-66) high in PDA compared to normal tissues, indicating this panel has diagnostic value too. We believe this project is the first step for this approach, and this concept needs to be evolved with prospective studies and larger samples. The ep-Sigs with a panel of epigenetic markers with a proven influence on resistance to frequently used drugs could help in developing meaningful models that change the approach to managing PDA, especially for NAT. Citation Format: Ashish Manne, Wancai Yang, Davendra Sohal, Ashwini Esnakula, Lianbo Yu. Developing prognostic signatures (ep-Sigs) through epigenetic predictive markers in pancreatic ductal adenocarcinoma (PDA) – A pilot study based on The Cancer Genome Atlas (TCGA) data [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B111.

ACEK Biosensor for the Minute-Scale Quantification of Breast Cancer ctDNA.

Circulating tumor DNA (ctDNA) appears as a valuable liquid biopsy biomarker in the early diagnosis, treatment, and prognosis of cancer. Here, a biosensing method derived from the AC electrokinetics (ACEK) effect was constructed in this study for the simple, efficient, and rapid method of detection of ctDNA. In the proof-of-concept experiment, ctDNA from the PIK3CA E542K mutant in breast cancer was quantified by detecting a normalized capacitance change rate using a forked-finger gold electrode as the sensing electrode in combination with the ACEK effect. We compared two formats for the construction of the approach by employing varied immobilization strategies; one is to immobilize the DNA capture probe on the electrode surface by Au-S bonding, while the other immobilizes the probe on a self-assembled membrane on the electrode surface by amide bonding. Both formats demonstrated ultrafast detection speed by completing the ctDNA quantification within 1 min and a linear range of 10 fM-10 pM was observed. Meanwhile, the immobilization via the self-assembled membrane yielded improved stability, sensitivity, and specificity than its Au-S bonding counterpart. A detection limit of 1.94 fM was eventually achieved using the optimized approach. This research provides a label-free and minute-scale universal method for the detection of various malignant tumors. The ctDNA biosensors based on the ACEK effect improved according to the probe type or electrode structure and have potential applications in tumor drug efficacy prediction, drug resistance monitoring, screening of high-risk groups, differential diagnosis, monitoring of tiny residual lesions, and prognosis determination.

Overcoming Chemotherapy Resistance in Metastatic Cancer: A Comprehensive Review.

The management of metastatic cancer is complicated by chemotherapy resistance. This manuscript provides a comprehensive academic review of strategies to overcome chemotherapy resistance in metastatic cancer. The manuscript presents background information on chemotherapy resistance in metastatic cancer cells, highlighting its clinical significance and the current challenges associated with using chemotherapy to treat metastatic cancer. The manuscript delves into the molecular mechanisms underlying chemotherapy resistance in subsequent sections. It discusses the genetic alterations, mutations, and epigenetic modifications that contribute to the development of resistance. Additionally, the role of altered drug metabolism and efflux mechanisms, as well as the activation of survival pathways and evasion of cell death, are explored in detail. The strategies to overcome chemotherapy resistance are thoroughly examined, covering various approaches that have shown promise. These include combination therapy approaches, targeted therapies, immunotherapeutic strategies, and the repurposing of existing drugs. Each strategy is discussed in terms of its rationale and potential effectiveness. Strategies for early detection and monitoring of chemotherapy drug resistance, rational drug design vis-a-vis personalized medicine approaches, the role of predictive biomarkers in guiding treatment decisions, and the importance of lifestyle modifications and supportive therapies in improving treatment outcomes are discussed. Lastly, the manuscript outlines the clinical implications of the discussed strategies. It provides insights into ongoing clinical trials and emerging therapies that address chemotherapy resistance in metastatic cancer cells. The manuscript also explores the challenges and opportunities in translating laboratory findings into clinical practice and identifies potential future directions and novel therapeutic avenues. This comprehensive review provides a detailed analysis of strategies to overcome chemotherapy resistance in metastatic cancer. It emphasizes the importance of understanding the molecular mechanisms underlying resistance and presents a range of approaches for addressing this critical issue in treating metastatic cancer.

A spatio-temporal model of multi-marker antimalarial resistance.

The emergence and spread of drug-resistant Plasmodium falciparum parasites have hindered efforts to eliminate malaria. Monitoring the spread of drug resistance is vital, as drug resistance can lead to widespread treatment failure. We develop a Bayesian model to produce spatio-temporal maps that depict the spread of drug resistance, and apply our methods for the antimalarial sulfadoxine-pyrimethamine. We infer from genetic count data the prevalences over space and time of various malaria parasite haplotypes associated with drug resistance. Previous work has focused on inferring the prevalence of individual molecular markers. In reality, combinations of mutations at multiple markers confer varying degrees of drug resistance to the parasite, indicating that multiple markers should be modelled together. However, the reporting of genetic count data is often inconsistent as some studies report haplotype counts, whereas some studies report mutation counts of individual markers separately. In response, we introduce a latent multinomial Gaussian process model to handle partially reported spatio-temporal count data. As drug-resistant mutations are often used as a proxy for treatment efficacy, point estimates from our spatio-temporal maps can help inform antimalarial drug policies, whereas the uncertainties from our maps can help with optimizing sampling strategies for future monitoring of drug resistance.

Assessing Treatment Efficacy and Determinants of Outcome in Isoniazid Mono-resistant Tuberculosis Patients: A Prospective Observational Study in Gujarat

Introduction: There is a high number of isoniazid-resistant tuberculosis (TB) in India; estimates imply that over 25% of TB patients there are isoniazid-resistant. Hence, the study aimed to evaluate the effectiveness of therapy for patients with isoniazid-mono-resistant TB and the negative effects of the H-mono-resistant TB Regime. Materials and Methods: It was a hospital-based prospective observational study from September 2021 to August 2022. Hence, 100 patients diagnosed with isoniazid mono-resistance TB enrolled in this study. After obtaining the prior informed consent of all patients willing to approve the collection and publication of their data, including extensive clinical history and radiological, microbiological, and biochemical investigations, this study included all diagnosed cases of isoniazid mono-resistant TB. A descriptive statistical analysis was done for continuous and categorical variables. Differences in characteristics between participants were tested with logistic regression and cross-tabulation. P <0.05 was considered significant. Results: Among 100 patients participated, their mean age was 50.8 ± 3.2 years. About 72 (72%) participants have successful treatment outcomes (cure). Only about 25 (25%) patients had minor adverse drug reactions. Body mass index (16.6 [3.6–74]), substance addiction history (9.5 [3.3–26.9]), previous history of TB (9 [3.3–24.0]), type of lesion (5.3 [1.6–17]), and extent of the lesion (2.6 [1.03–6.07]) in chest X-ray were associated statistically with the treatment outcome. Conclusion: The findings suggest that the H-mono-resistance regime is generally well-tolerated, with only a small percentage of patients experiencing nonserious adverse drug reactions, and the overall successful treatment outcome in H-mono patients was 72%. The study also highlights the importance of monitoring drug resistance patterns, particularly for levofloxacin and moxifloxacin, and the need for effective treatment regimens for isoniazid mono-resistant pulmonary TB.

Emergence of plasmid-mediated tigecycline resistance tet(X4) gene in Enterobacterales isolated from wild animals in captivity

BackgroundOver the past few decades, antimicrobial resistance (AMR) has emerged as a global health challenge in human and veterinary medicine. Research on AMR genes in captive wild animals has increased. However, the presence and molecular characteristics of tet(X)-carrying bacteria in these animals remain unknown. MethodsEighty-four samples were collected from captive wild animals. tet(X) variants were detected using polymerase chain reaction and the isolates were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. All isolated strains were subjected to antimicrobial susceptibility testing and whole-genome sequencing. The virulence of an Escherichia coli strain carrying enterotoxin genes was assessed using a Galleria mellonella larval model. ResultsWe isolated two tet(X4)-positive E. coli strains and one tet(X4)-positive Raoultella ornithinolytica strain. Antimicrobial susceptibility tests revealed that all three tet(X4)-carrying bacteria were sensitive to the 13 tested antimicrobial agents, but exhibited resistance to tigecycline. Notably, one tet(X4)-carrying E. coli strain producing an enterotoxin had a toxic effect on G. mellonella larvae. Whole-genome sequencing analysis showed that the two tet(X4)-carrying E. coli strains had more than 95% similarity to tet(X4)-containing E. coli strains isolated from pigs and humans in China. ConclusionThe genetic environment of tet(X4) closely resembled that of the plasmid described in previous studies. Our study identified tet(X4)-positive strains in wildlife and provided valuable epidemiological data for monitoring drug resistance. The identification of enterotoxin-producing E. coli strains also highlights the potential risks posed by virulence genes.

Artemisinin resistance-associated gene mutations in Plasmodium falciparum: A case study of severe malaria from Mozambique

BackgroundThe effectiveness of artemisinin-based combination therapies (ACT) in treating Plasmodium falciparum, is vital for global malaria control efforts, particularly in sub-Saharan Africa. The examination of imported cases from endemic areas holds implications for malaria chemotherapy on a global scale. MethodA 45-year-old male presented with high fever, dry cough, diarrhoea and generalized muscle pain, following a two-week trip to Mozambique. P. falciparum infection with hiperparasitemia was confirmed and the patient was treated initially with quinine and doxycycline, then intravenous artesunate. To assess drug susceptibility, ex vivo half-maximal inhibitory concentration assays were conducted, and the isolated P. falciparum genome was deep sequenced. ResultsThe clinical isolate exhibited elevated ex vivo half-maximal inhibitory concentration values to dihydroartemisinin, lumefantrine, mefloquine and piperaquine. Genomic analysis identified a I416V mutation in the P. falciparum Kelch13 (PF3D7_1343700) gene, and several mutations at the Kelch13 interaction candidate genes, pfkics (PF3D7_0813000, PF3D7_1138700, PF3D7_1246300), including the ubiquitin carboxyl-terminal hydrolase 1, pfubp1 (PF3D7_0104300). Mutations at the drug transporters and genes linked to next-generation antimalarial drug resistance were also present. ConclusionsThis case highlights the emergence of P. falciparum strains carrying mutations in artemisinin resistance-associated genes in Mozambique, couple with a reduction in ex vivo susceptibility to ACT drugs. Continuous surveillance of mutations linked to drug resistance and regular monitoring of drug susceptibility are imperative to anticipate the spread of potential resistant strains emerging in Mozambique and to maintain effective malaria control strategies.

Tropical infectious diseases and the skin: Diagnostic and treatment updates since the WHO's integrated campaign against neglected tropical skin diseases

AbstractIntroductionThe World Health Organization (WHO) initiated a unified effort to address skin‐related neglected tropical diseases (NTDs) in 2017. This effort increased attention and resources allocated toward decreasing the burden of tropical skin diseases. It emphasized an “integrated approach” to detect and treat multiple co‐existing NTDs at once. This article will outline new diagnostic tests, treatment options, and vaccine development for neglected tropical skin diseases since the initiative began.Data SourcesA PubMed search of clinical trials, randomized controlled trials, systematic reviews, and meta‐analyses published since 2017 was performed.ResultsThe WHO's initiative has already seen success, increasing the surveillance of leprosy and the distribution of treatment for yaws. It has encouraged the development of new point‐of‐care tests and better‐tolerated treatment options. It has also brought new challenges, with the rise of resistant organisms. Development of point‐of‐care DNA‐RNA‐based testing may improve drug resistance monitoring. New vaccines are needed for long‐term control of skin NTDs in areas with high transmission rates.

Antifungal susceptibility of clinically isolated invasive Candida tropicalis in East China from 2017 to 2021

Objective: To explore the epidemiological characteristics of sample distribution and antifungal susceptibilities of clinically invasive C. tropicalis isolates from 2017 to 2021 in East China. Methods: Using a retrospective analysis, the East China Invasive Fungal Infection Group (ECIFIG) collected C. tropicalis clinically isolated from 32 hospitals in East China between January 2017 and December 2021. The identification results of the strains were reviewed using mass spectrometry by the central laboratory of the Shanghai East Hospital. The minimum inhibitory concentrations (MICs) of the strains against fluconazole (FLU), voriconazole (VOR), itraconazole (ITR), Posaconazole (POS), isavuconazole (ISA), anidulafungin (ANI), caspofungin (CAS), micafungin (MICA) and 5-fluorocytosine (FCT) were tested by the ThermoFisher CMC1JHY colorimetric microdilution method. The MIC of amphotericin B (AMB) was tested by the broth microdilution method. The MIC results were analyzed based on the clinical breakpoints and epidemiological cutoff values (ECV) published by the Clinical and Laboratory Standards Institute (CLSI) M27 Ed3 and M57 Ed4 documents. Data analysis was conducted using the Kruskal-Wallis test and paired t-test. Results: In total, 305 C. tropicalis isolates were collected. There were 38.0% (116/305) strains isolated from blood, 11.5% (35/305) ascites, 8.9% (27/305) catheter and 8.9% (27/305) drainage fluid. The resistance rate of C. tropicalis to FLU was 32.5%, to VOR was 28.5%, and the cross-resistance rate to FLU and VOR was 28.5%. The wild-type proportions for ITR and POS were 79.3% and 29.2% respectively. There was no significant difference in resistance rates, MIC50, and MIC90 of FLU and VOR, or in the wild-type rates of ITR and POS over five years. More than 95.0% of the isolates were susceptible to echinocandins. However, one strain was identified as being multi-drug resistant. In azole antifungals, voriconazole, itraconazole, posaconazole, and isavuconazole have similar GM MIC values. The GM MIC of fluconazole is significantly higher than that of itraconazole (t=9.95, P<0.05), posaconazole (t=9.99, P<0.05), and voriconazole (t=10.01, P<0.05), Meanwhile, among echinocandins, the GM MIC of ANI was comparable to that of CAS (t=1.17, P>0.05), both of which were significantly higher than MICA (t=11.56, P<0.05; t=4.15, P<0.05). Conclusion: The clinical isolates of C. tropicalis in East China from 2017 to 2021 were relatively susceptible to echinocandins. However, there was consistently high resistance to fluconazole and voriconazole. More intensive efforts should be made on the monitoring of drug resistance in C. tropicalis.

B-016 Automated Next Generation Sequencing Fluidic-Based Device for Sample to Library Preparation: A Flexible Solution for Rapid Decentralized Sequencing for Infectious Disease Diagnostics

Abstract Background In addition to the established use of Next Generation Sequencing (NGS), such as drug resistance monitoring in HIV, the recent COVID19 pandemic has shown the crucial need of NGS technologies as tools for identification of clinically relevant variants of the SARS-CoV-2 virus. Typically, in these settings, to be cost-effective most NGS analyses were conducted using larger batch sizes often resulting in long turn-around times of 2–3 weeks the need of trained personnel, and centralized testing facilities. Methods We have developed an easy to use automated fluidic-based benchtop device to bridge a perceived gap in NGS library preparation and provide a solution for decentralized testing that does not require specially trained personnel. With a batch size of 6, smaller hospitals and laboratories can perform NGS library preparation on fresh or archived samples with a fast turn-around-time of two days, facilitating earlier reporting to speed up diagnosis and treatment. The Helaxy NGS fluidic device performs sample nucleic acid extraction and a 2-step PCR in a plastic fluidic card, which is the sole consumable required for the extraction and library prep process.The sample is applied to the fluidic card by manual pipetting followed by loading of the card into the device. Nucleic acids are extracted with a combination of magnetic bead pull-down and centrifugal force in a purification chamber to give an eluate that is spun to a separate PCR chamber that uses the concept of thermal induction and cycling. Barcoding for library preparation follows within the same PCR chamber and the resulting product is transferred into another fluidic card for size selection purification, normalization and pooling to generate a library for input into compatible NGS sequencers, e.g., but not confined to, Illumina instruments. Results In order to demonstrate clinical utility we have shown that the Helaxy NGS fluidic device can successfully extract nucleic acid from at least three sample types: SARS-CoV-2 RNA from nasopharyngeal swabs, HIV RNA from plasma and 16S RNA from stools. Using in-house and commercial assays, we have generated libraries of target amplicons using the fluidic device workflow followed by sequencing with Illumina sequencers iSeq and MiSeq. Sequencing results analysed and reported by the Helaxy NGS Bioinformatics Reporting Pipeline revealed expected variants and mutations in the samples. We correctly identified all the unique mutations such as L211del and G446S in commercially available inactivated Omicron BA1 variant of the SARS-CoV-2 virus as well as characterised drug-resistant mutations such as L90M in the Protease gene and D67N and Y181C in the Reverse Transcriptase gene in commercially available inactivated HIV-1 virus. Conclusion The Helaxy NGS fluidic device can thus effectively provide an easy-to-use automated solution for sample library preparation in decentralized facilities to reduce the turn-around-time from sample collection to result reporting for clinical diagnosis and treatment.

Development of a NIR fluorescent probe for fluorescence-assisted EGFR-TKI applicable patients screening and drug resistance monitoring

EGFR tyrosine kinase inhibitor exerts significant benefits to non-small cell lung cancer patient, but was also limited by the applicable patient screening and drug resistance. Here we presented with an EGFR-targeted and reactive oxygen species-responsive NIR probe (LX) to achieve both patient screening and drug resistance monitoring for EGFR-tyrosine kinase inhibitor. LX inherited EGFR selectivity and preference from EGFR-tyrosine kinase inhibitor, which only showed specificity to tumor with EGFR mutation. Meanwhile, the near-infrared fluorescence of LX was initially inhibited and could be turned on by intratumoral reactive oxygen species. When LX could bind to tumor EGFR, reactive oxygen species-responsive specific fluorescence was generated to indicate the applicability of tumors to EGFR-tyrosine kinase inhibitor. However, no specific LX fluorescence could be observed in inapplicable tumors due to the lack of specificity between tumor EGFR and LX. Meanwhile, when drug resistance was developed during treatments, obvious intratumoral reactive species oxygen decrease happened, which was also deemed as a significant signal of the drug resistance. By visualizing intratumoral reactive oxygen species fluctuation by responsive fluorescence, drug resistance could be monitored and reported.