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With intensive and extensive using herbicides, the level of weed resistance was increased, new resistance mechanisms are constantly being discovered. Adcances on the mechanisms of target-site resistance (TSR) and non-target-site resistance (NTSR) in recent ten years were summarized in this paper. The progress of TSR mainly included new resistance mutation in herbicide target enzymes of acetolactate synthase, acetyl-CoA carboxylase and 5-enolpyruvylshikimate-3-phosphatesynthase, as well as various resistance mutations occurring in target enzyme and multiple mutated target isozymes that resisting stronger herbicide selection. In addition, the roles of NTSR in glyphosate resistance of cytochrome P450 (CYP81), aldo-keto reductase and ABC transporter protein (EcABCC8) were also described in detail. This paper is beneficial for understanding the molecular mechanisms and evolutionary laws of weed resistance from more profound and comprehensive perspective, and also provides inspriration for scientifically using herbicides and designing new herbicides with new mode of action. [ABSTRACT FROM AUTHOR]

Background: Patients with tuberculosis resistant to isoniazid but susceptible to rifampicin (Hr-Rs TB) remain a neglected demographic, despite a high disease burden and poor outcomes of these patients. The aim of this study was to investigate the characteristics of isoniazid-resistance-related mutations in Mycobacterium tuberculosis and resistance rates to drugs included in WHO-recommended regimens for Hr-Rs patients. Methods: Mycobacterium tuberculosis isolates (n = 4922) obtained from national tuberculosis drug-resistance surveillance were subjected to whole-genome sequencing to identify Hr-Rs strains. The minimal inhibitory concentrations (MICs) were established for the Hr-Rs strains to determine the isoniazid resistance levels. We also identified drug-resistance-associated mutations for five drugs (fluoroquinolones, ethambutol, pyrazinamide, streptomycin, and amikacin) in the Hr-Rs strains. Results: Of the 4922 strains, 384 (7.8 %) were Hr-Rs. The subculture of seven strains failed, so 377 (98.2 %) strains underwent phenotypic MIC testing. Among the 384 genotypic Hr-Rs strains, 242 (63.0 %) contained the katG Ser315Thr substitution; 115 (29.9 %) contained the -15C>T in the promoter region of the fabG1 gene; and 16 (4.2 %) contained Ser315Asn in the katG gene. Of the 239 strains with the Ser315Thr substitution, 229 (95.8 %) had MIC ≥ 2 µg/mL, and of the 114 strains with the -15C>T mutation, 103 (90.4 %) had 0.25 µg/mL ≤ MIC ≤ 1 µg/mL. The genotypic resistance rates were 0.8 % (3/384) for pyrazinamide, 2.3 % (9/384) for ethambutol and fluoroquinolones; 39.6 % (152/384) of the strains were resistant to streptomycin, but only 0.5 % (2/384) of the strains were resistant to amikacin. Conclusion: Ser315Thr in katG was the predominant mutation conferring the Hr-Rs phenotype, followed by the fabG1 -15C>T mutation. The combination of rifampicin, pyrazinamide, ethambutol, and levofloxacin should be effective in the treatment of patients with Hr-Rs tuberculosis because the resistance rates for these drugs in China are low.

ABSTRACT The use of valganciclovir as secondary prophylaxis for cytomegalovirus (CMV) infection in solid organ transplantation (SOT) is the most prevalent therapeutic choice, but it has been dismissed by the presence of resistance and toxicity. Letermovir (LMV) is indicated as primary prophylaxis in hematopoietic stem cell transplantation, but there is scarce clinical data on its use as secondary prophylaxis in SOT. We present two cases of SOT recipients (lung, liver) who underwent LMV secondary prophylaxis. One patient developed the L595S (UL97)-resistant mutation to ganciclovir/valganciclovir and experienced several CMV relapses under LMV therapy, but no LMV resistance mutations were detected. The second patient developed the C325F (UL56)-resistant mutation to LMV under secondary prophylaxis which was rescued by foscarnet. This observation reviews previously published clinical data on LMV secondary prophylaxis and recommends a cautious use of LMV in the clinical practice due to the early development of UL56 resistance mutations. IMPORTANCE This observation provides comprehensive data on the clinical correlates of both cytomegalovirus (CMV) genotypic follow-up and clinical monitoring and outcomes for two different solid organ transplantation recipients that received letermovir as secondary prophylaxis. Our study emphasizes that monitoring of CMV disease in the patient and early genotypic detection of resistance mutations are essential when using new antiviral drugs for off-label indication in patients experiencing CMV relapses or not responding to standard antiviral therapy. These cases and the bibliography reviewed can be helpful for other researchers and clinicians working in the field to optimize the use of new treatments for transplant recipients since drug-resistant CMV infection is an important emerging problem even with new developments in antiviral treatment.

ABSTRACTIn this study, we examined the occurrence of acquired and transmitted drug resistance to integrase strand transfer inhibitor (INSTI) in HIV-1 strains in Chongqing (China) for guiding for the routine testing of INSTI-associated HIV-1 genotype resistance. Plasma samples were obtained from HIV-1 patients at Chongqing Public Health Medical Center from July 2019 to August 2022. Besides, amplification, sequence, and analysis of the portion of the HIV-1 pol gene that encodes the integrase protein were implemented to identify INSTI resistance. Integrase sequence data was harvested for a comprehensive cohort of 1032 patients infected with HIV-1. This cohort consisted of 564 ART-naive patients, 465 ART-treated patients, and 3 patients with an unknown treatment history. Within the study group, we identified INSTI resistance in 21 patients (2.03%, 21/1032), including 17 ART-treated patients (3.66%, 17/465). Among the ART-treated patients, 12 were INSTI-treated (11.76%, 12/102), 5 were INSTI-naive (1.38%, 5/363), and 4 were ART-ineffective patients (0.71%, 4/564). The prevalent major resistance mutation was Q148R (0.48%, 5/1032), while the most prevalent accessory resistance mutation was E157Q (1.65%, 17/1032). In light of the above, it is recommended that the incidence of accessory genotype analysis should be considered before starting any future INSTI-based therapy, especially in patients with drug resistance to NRTIs and NNRTIs and the reduction of INSTI sensitivity should be carefully monitored and investigated. Regular monitoring for resistance should be implemented after the use of INSTIs, and, importantly, ongoing monitoring of the decreasing susceptibility to INSTIs is crucial following the initiation of treatment with INSTIs.

Introduction: ALK tyrosine kinase inhibitors (ALK TKIs) have improved prognosis in ALK-rearranged (ALK+) non-small-cell lung cancer (NSCLC). However, drug resistance mechanisms occur inevitably during the course of treatment leading to disease progression. Activation of epidermal growth factor receptor (EGFR) bypass signaling pathway is an uncommon cause of acquired resistance to ALK TKIs. Method: We present two patients with EML4-ALK rearranged NSCLC, developing an acquired EGFR resistance mutation after receiving multiple lines of ALK TKIs. Results: While preclinical models have showed encouraging data, there is a critical need for clinical studies on treatment strategies to overcome this drug resistance. Three real-life therapeutic approaches were used in this report: i) using brigatinib, an inhibitor targeting both ALK and EGFR tyrosine kinases; ii) combining two ALK TKIs together; and iii) delivering doublet platinum chemotherapy. In case 1, time to treatment failure (TTF) was 9.5 months with brigatinib; in case 2, TTF was 10 months with combined TKIs (osimertinib and brigatinib), whereas TTF with chemotherapy was only 2 months. Tolerability profile TKIs combotherapy was acceptable. Conclusion: These case reports underline the therapeutic complexity of EGFRacquired resistance mutation in ALK+ NSCLC and offers some leads to solve this real-life clinical challenge. [ABSTRACT FROM AUTHOR]

Prototypic Staphylococcus aureus and their small-colony variants (SCVs) are predominant in cystic fibrosis (CF), but the interdependence of these phenotypes is poorly understood. We characterized S. aureus isolates from adult CF patients over several years. Of 18 S. aureus-positive patients (58%), 13 (72%) were positive for SCVs. Characterization included genotyping, SCCmec types, auxotrophy, biofilm production, antibiotic susceptibilities and tolerance, and resistance acquisition rates. Whole-genome sequencing revealed that several patients were colonized with prototypical and SCV-related clones. Some clonal pairs showed acquisition of aminoglycoside resistance that was not explained by aminoglycoside-modifying enzymes, suggesting a mutation-based process. The characteristics of SCVs that could play a role in resistance acquisition were thus investigated further. For instance, SCV isolates produced more biofilm (p < 0.05) and showed a higher survival rate upon exposure to ciprofloxacin and vancomycin compared to their prototypic associated clones. SCVs also developed spontaneous rifampicin resistance mutations at a higher frequency. Accordingly, a laboratory-derived SCV (ΔhemB) acquired resistance to ciprofloxacin and gentamicin faster than its parent counterpart after serial passages in the presence of sub-inhibitory concentrations of antibiotics. These results suggest a role for SCVs in the establishment of persistent antibiotic-resistant clones in adult CF patients. [ABSTRACT FROM AUTHOR]

Simple Summary: Megalurothrips usitatus is the main pest of cowpea in China, mainly by feeding on plant leaves and spreading plant viruses. In this study, a new mutation putative site, I873S, was correlated with pyrethroid resistance. According to the results of the bioassay, an I873S mutation may be associated with the resistance of M. usitatus to pyrethroids. The results of this study will promote the development of research on the resistance of M. usitatus to pyrethroids and provide guidance for improving the management system of M. usitatus in the future. Pyrethroid resistance of thrips has been reported in many countries, and knockdown resistance (kdr) has been identified as a main mechanism against pyrethroids in many insects. To characterize pyrethroid resistance in Megalurothrips usitatus from the Hainan Province of China, we conducted a biological assay and sequenced the voltage-gated sodium channel gene domain II from M. usitatus field populations. It showed high resistance to the pyrethroids for 2019 and 2020, in which LC50 to lambda-cyhalothrin of M. usitatus was 1683.521 mg/L from Sanya in 2020. The LC50 value of deltamethrin was lower in Haikou than in other locations, which mean the south of Hainan has higher resistance than the north of Hainan. Two mutations of I873S and V1015M were detected in the domain II region of the sodium channel in M. usitatus; however, the mutation frequency of V1015M was only 3.33% and that of I873S was 100%. One is homozygous and the other is a heterozygous mutant type. The three thrips-sensitive strains of sodium channel 873 are highly conserved in amino acids (isoleucine), while the M. usitatus pyrethroid-resistant strains are all serine, so I873S may be related to the resistance of M. usitatus to pyrethroids. The present study will contribute to the understanding of the evolution of pyrethroids resistance and contribute to the development of resistance management of M. usitatus in Hainan. [ABSTRACT FROM AUTHOR]

Lorlatinib, a third-generation anaplastic lymphoma kinase (ALK)/receptor tyrosine kinase inhibitor (ROS1), demonstrated efficacy in ROS1 positive (ROS1+) non-small cell lung cancer (NSCLC), although approval is currently limited to the treatment of ALK+ patients. However, lorlatinib-induced resistance mechanisms, and its efficacy against the resistance mutation G2032R in ROS1, respectively, have not yet been fully understood. Furthermore, concomitant tumor suppressor gene p53 (TP53) mutations occur in driver alteration positive NSCLC, but their prognostic contribution in the context of ROS1 inhibition remains unclear. Here we report a ROS1+ NSCLC patient who developed an on target G2032R resistance mutation during second-line lorlatinib treatment, indicating the lack of activity of lorlatinib against ROS1 G2032R. The resistance mutation was detected in plasma-derived ctDNA, signifying the clinical utility of liquid biopsies.

Jinghua Sun,1,&ast; Ge Sun,1,&ast; KeMou Lu,1 Lingling Xu,1 XiaoNa Qu,1 Ye Cheng,1 Evenki Pan,2 Peng Yang,2 Tingting Wu,2 Yang Zhang,1 HongMei He1 1The Second Affiliated Hospital of Dalian Medical University, Dalian, People’s Republic of China; 2Nanjing Geneseeq Technology Inc., Nanjing, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Yang Zhang; HongMei He, The Second Affiliated Hospital of Dalian Medical University, Dalian, No. 467, Zhongshan Road, Shahekou District, Dalian, People’s Republic of China, Email zydley@163.com; hongmeihe1976@163.comAbstract: For advanced non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations, EGFR tyrosine kinase inhibitors (TKIs) have been approved as the standard therapy and shown clinical benefits. However, the emergence of drug resistance is inevitable. Tumor heterogeneity was often observed by imaging method to evaluate the progression of primary and metastatic lesions. Tissue biopsy was also unlikely to accurately capture the complete genomic landscape from a single tissue sample. Recently, genomic characterization of circulating tumor DNA (ctDNA) offer an opportunity to reveal the clonal dynamics throughout the course of a patient’s illness and provide comprehensive genomic landscape of tumors to assess tumor heterogeneity. Here, we reported a lung adenocarcinoma (LADC) with EGFR mutations who was treated with sequential EGFR TKIs. The CT image of the patient’s different lesions suggested that dynamic change of tumor heterogeneity had occurred. Targeted next-generation sequencing (NGS) analysis of ctDNA revealed dynamic changes of mutational profiles between the primary and metastatic tumors to discover tumor evolution to guide treatment decision-making.Keywords: tumor heterogeneity, circulating tumor DNA, ctDNA, resistance mutation, next-generation sequencing, NGS

The IDX17119 is a phosphonomidate-based pan-genotypic non-nucleoside inhibitor of Hepatitis C Virus (HCV) NS5B RdRp thumb-II domain. IDX17119 exhibits significant antiviral activity against HCV genotype (GT) 1a, 2a, 3a and 4a. The molecular docking analysis was performed to understand the binding and intermolecular interactions of the IDX17119 molecule at the thumb-II domain of 1a, 2a, 3a and 4a GT NS5B RdRps. The molecular dynamics simulation has been performed to determine the stability of the ligand–protein complexes. We found GT 1a complex is relatively stable compared with other drug-receptor complexes. The binding free energy calculations and free energy decomposition analysis were carried out for all the complexes, the result revealed that the increase in the unfavourable polar contribution affects the binding of IDX17119 with GT 2a NS5B RdRp compared with all other complexes. In addition to this, the effect of mutation at M423 site (M423T/V) alters the conformation and activity of the IDX17119 molecule. [ABSTRACT FROM AUTHOR]

IntroductionALK tyrosine kinase inhibitors (ALK TKIs) have improved prognosis in ALK-rearranged (ALK+) non-small-cell lung cancer (NSCLC). However, drug resistance mechanisms occur inevitably during the course of treatment leading to disease progression. Activation of epidermal growth factor receptor (EGFR) bypass signaling pathway is an uncommon cause of acquired resistance to ALK TKIs.MethodWe present two patients with EML4-ALK rearranged NSCLC, developing an acquired EGFR resistance mutation after receiving multiple lines of ALK TKIs.ResultsWhile preclinical models have showed encouraging data, there is a critical need for clinical studies on treatment strategies to overcome this drug resistance. Three real-life therapeutic approaches were used in this report: i) using brigatinib, an inhibitor targeting both ALK and EGFR tyrosine kinases; ii) combining two ALK TKIs together; and iii) delivering doublet platinum chemotherapy. In case 1, time to treatment failure (TTF) was 9.5 months with brigatinib; in case 2, TTF was 10 months with combined TKIs (osimertinib and brigatinib), whereas TTF with chemotherapy was only 2 months. Tolerability profile TKIs combotherapy was acceptable.ConclusionThese case reports underline the therapeutic complexity of EGFR-acquired resistance mutation in ALK+ NSCLC and offers some leads to solve this real-life clinical challenge.

Integrase strand transfer inhibitor (INSTI)-containing regimens in HIV-1- infected patients have experienced a global increase. Recently, WHO has emphasized the need to fast-track the transition to dolutegravir (DTG)- based antiretroviral (ARV) treatments. However, continued surveillance of INSTI resistance is recommended. In this study, clinical, epidemiological, and virological features associated with INSTI resistance diagnosed in Spain were analyzed. Samples collected between 2008 and 2021 from HIV-1-infected patients were analyzed in integrase, protease, and reverse transcriptase using Sanger population sequencing. ARV drug resistance was evaluated with the Stanford University HIVdb program. Among 2,696 patients, 174 (6.5%) had INSTI resistance, all of them to first-generation INSTIs, and 71 (2.6%) had also resistance to second-generation INSTIs. Of these, only 5 individuals were exposed to DTG as the only INSTI, in whom resistance development was associated with poor treatment adherence and/or resistance to other ARV classes. Of newly HIV-1-diagnosed individuals, 0.92% harbored INSTI-resistant viruses, with low prevalences maintained along time, and only one had low-level resistance to DTG. Persons who inject drugs, age over 39 years, resistance to other ARV classes, and longer time from diagnosis were associated with INSTI resistance (p < 0.001). Non-subtype B INSTI-resistant viruses lacked the Q148H + G140S resistance pathway and showed lower INSTI resistance levels than subtype B viruses. In conclusion, INSTI resistance is uncommon and associated with long-term infections, older age and additional resistance to other ARV drug classes, and is rare in newly diagnosed HIV-1 infections. Our results also support the preferential use of DTG-containing regimens in first-line treatments, although surveillance of INSTI resistance is encouraged. [ABSTRACT FROM AUTHOR]

Integrase strand transfer inhibitor (INSTI)-containing regimens in HIV-1-infected patients have experienced a global increase. Recently, WHO has emphasized the need to fast-track the transition to dolutegravir (DTG)-based antiretroviral (ARV) treatments. However, continued surveillance of INSTI resistance is recommended. In this study, clinical, epidemiological, and virological features associated with INSTI resistance diagnosed in Spain were analyzed. Samples collected between 2008 and 2021 from HIV-1-infected patients were analyzed in integrase, protease, and reverse transcriptase using Sanger population sequencing. ARV drug resistance was evaluated with the Stanford University HIVdb program. Among 2,696 patients, 174 (6.5%) had INSTI resistance, all of them to first-generation INSTIs, and 71 (2.6%) had also resistance to second-generation INSTIs. Of these, only 5 individuals were exposed to DTG as the only INSTI, in whom resistance development was associated with poor treatment adherence and/or resistance to other ARV classes. Of newly HIV-1-diagnosed individuals, 0.92% harbored INSTI-resistant viruses, with low prevalences maintained along time, and only one had low-level resistance to DTG. Persons who inject drugs, age over 39 years, resistance to other ARV classes, and longer time from diagnosis were associated with INSTI resistance (p

Lorlatinib, a third-generation anaplastic lymphoma kinase (ALK)/receptor tyrosine kinase inhibitor (ROS1), demonstrated efficacy in ROS1 positive (ROS1+) non-small cell lung cancer (NSCLC), although approval is currently limited to the treatment of ALK+ patients. However, lorlatinib-induced resistance mechanisms, and its efficacy against the resistance mutation G2032R in ROS1, respectively, have not yet been fully understood. Furthermore, concomitant tumor suppressor gene p53 (TP53) mutations occur in driver alteration positive NSCLC, but their prognostic contribution in the context of ROS1 inhibition remains unclear. Here we report a ROS1+ NSCLC patient who developed an on target G2032R resistance mutation during second-line lorlatinib treatment, indicating the lack of activity of lorlatinib against ROS1 G2032R. The resistance mutation was detected in plasma-derived ctDNA, signifying the clinical utility of liquid biopsies. [ABSTRACT FROM AUTHOR]

Over the past 20 years, the management of gastrointestinal stromal tumors has acted as an important model in the advancement of molecularly targeted therapies for solid tumors. The success of imatinib has established it as a lasting therapy in the management of early-stage and advanced disease in the first-line setting. Imatinib resistance inevitably develops, resulting in the need for further lines of therapy. Ripretinib is an orally administered switch-control tyrosine kinase inhibitor, specifically developed to target both primary and secondary KIT and PDGFRα resistance mutations. Herein, the authors discuss the molecular rationale, the preclinical evidence and the clinical use of ripretinib in the treatment of gastrointestinal stromal tumors in the advanced stages of disease. [ABSTRACT FROM AUTHOR]

Tyrosine Kinase Inhibitors (TKI), such as Imatinib, are known for their effectiveness in achieving complete remission from Chronic Myeloid Leukemia (CML), a malignancy caused by a reciprocal translocation between the terminal fragments of the long arms of chromosomes 9 and 22 that leads to the famous chimeric BCR::ABL1 gene. Mutations in this fusion gene may induce resistance to TKI treatment, which requires prescribing a second-, or third-generation TKI medication. We report here a case of a Moroccan CML patient with secondary resistance to the frontline TKI treatment (Imatinib), in which, BCR::ABL1 cDNA sequencing reveals the novel mutation p.K375M at the ABL1 Kinase Domain. In-silico prediction tools confirm the pathogenicity of the p.K375M substitution. Homology analysis indicated that the residue is highly conserved and located in a stable region. This potentially pathogenic mutation is likely to disrupt the BCR::ABL1-Imatinib binding, leading to the observed resistance. To overcome the treatment resistance, Imatinib should be substituted with a second-generation TKI medication, such as Dasatinib, Bosutinib, or Nilotinib. The present study further widens the spectrum of TKI resistance mutations and emphasizes particularly the crucial role of molecular investigation in personalizing treatment for CML patients, ensuring efficient follow-up and appropriate healthcare., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Bin Yao,1 Xue Han,2 Linrong Pang,1 Caihong Xu,1 Sisi Liu,2 Xiaochun Cheng,1 Jun Chen1 1Department of Radiotherapy and Chemotherapy, The Affiliated People’s Hospital of Ningbo University, Ningbo, Zhejiang, People’s Republic of China; 2Department of Research and Development, Nanjing Geneseeq Technology Inc., Nanjing, Jiangsu, People’s Republic of ChinaCorrespondence: Xiaochun Cheng; Jun ChenDepartment of Radiotherapy and Chemotherapy, The Affiliated People’s Hospital of Ningbo University, Ningbo, Zhejiang, People’s Republic of ChinaTel +86-13736005125; +86-13777975439Email cxc5125@163.com junchen201211@163.comAbstract: Anaplastic lymphoma kinase (ALK) rearrangement is extremely rare in lung squamous cell carcinoma (LSCC), and it remains controversial as to whether LSCC patients with ALK rearrangement can benefit from ALK tyrosine kinase inhibitors (TKIs). Here, we report an LSCC patient with ALK rearrangement who was treated with sequential ALK TKI therapies and experienced a clinical benefit of 35 months. Although the use of ALK TKIs showed clinical benefits, targeted next-generation sequencing (NGS) for dynamic monitoring of circulating tumor DNA (ctDNA) from patient plasma revealed the accumulation of ALK resistance mutations, which could provide valuable information in designing the treatment strategy. Our study highlights the importance of dynamic monitoring of ctDNA using NGS to discover tumor evolution to guide treatment decision-making and provides meaningful insights into the potential treatment options for ALK-positive LSCC patients.Keywords: ALK rearrangement, dynamic monitoring, resistance mutation, next-generation sequencing

Prototypic Staphylococcus aureus and their small-colony variants (SCVs) are predominant in cystic fibrosis (CF), but the interdependence of these phenotypes is poorly understood. We characterized S. aureus isolates from adult CF patients over several years. Of 18 S. aureus-positive patients (58%), 13 (72%) were positive for SCVs. Characterization included genotyping, SCCmec types, auxotrophy, biofilm production, antibiotic susceptibilities and tolerance, and resistance acquisition rates. Whole-genome sequencing revealed that several patients were colonized with prototypical and SCV-related clones. Some clonal pairs showed acquisition of aminoglycoside resistance that was not explained by aminoglycoside-modifying enzymes, suggesting a mutation-based process. The characteristics of SCVs that could play a role in resistance acquisition were thus investigated further. For instance, SCV isolates produced more biofilm (p < 0.05) and showed a higher survival rate upon exposure to ciprofloxacin and vancomycin compared to their prototypic associated clones. SCVs also developed spontaneous rifampicin resistance mutations at a higher frequency. Accordingly, a laboratory-derived SCV (ΔhemB) acquired resistance to ciprofloxacin and gentamicin faster than its parent counterpart after serial passages in the presence of sub-inhibitory concentrations of antibiotics. These results suggest a role for SCVs in the establishment of persistent antibiotic-resistant clones in adult CF patients.

Pyrethroid resistance of thrips has been reported in many countries, and knockdown resistance (kdr) has been identified as a main mechanism against pyrethroids in many insects. To characterize pyrethroid resistance in Megalurothrips usitatus from the Hainan Province of China, we conducted a biological assay and sequenced the voltage-gated sodium channel gene domain II from M. usitatus field populations. It showed high resistance to the pyrethroids for 2019 and 2020, in which LC50 to lambda-cyhalothrin of M. usitatus was 1683.521 mg/L from Sanya in 2020. The LC50 value of deltamethrin was lower in Haikou than in other locations, which mean the south of Hainan has higher resistance than the north of Hainan. Two mutations of I873S and V1015M were detected in the domain II region of the sodium channel in M. usitatus; however, the mutation frequency of V1015M was only 3.33% and that of I873S was 100%. One is homozygous and the other is a heterozygous mutant type. The three thrips-sensitive strains of sodium channel 873 are highly conserved in amino acids (isoleucine), while the M. usitatus pyrethroid-resistant strains are all serine, so I873S may be related to the resistance of M. usitatus to pyrethroids. The present study will contribute to the understanding of the evolution of pyrethroids resistance and contribute to the development of resistance management of M. usitatus in Hainan.

BACKGROUND: Fenpicoxamid and florylpicoxamid are picolinamide fungicides targeting the Qi site of the cytochrome bc1 complex, via their primary metabolites UK‐2A and CAS‐649, respectively. We explore binding interactions and resistance mechanisms for picolinamides, antimycin A and ilicicolin H in yeast by testing effects of cytochrome b amino acid changes on fungicide sensitivity and interpreting results using molecular docking. RESULTS: Effects of amino acid changes on sensitivity to UK‐2A and CAS‐649 were similar, with highest resistance associated with exchanges involving G37 and substitutions N31K and L198F. These changes, as well as K228M, also affected antimycin A, while ilicicolin H was affected by changes at G37 and L198, as well as Q22E. N31 substitution patterns suggest that a lysine at position 31 introduces an electrostatic interaction with neighbouring D229, causing disruption of a key salt‐bridge interaction with picolinamides. Changes involving G37 and L198 imply resistance primarily through steric interference. G37 changes also showed differences between CAS‐649 and UK‐2A or antimycin A with respect to branched versus unbranched amino acids. N31K and substitution of G37 by large amino acids reduced growth rate substantially while L198 substitutions showed little effect on growth. CONCLUSION: Binding of UK‐2A and CAS‐649 at the Qi site involves similar interactions such that general cross‐resistance between fenpicoxamid and florylpicoxamid is anticipated in target pathogens. Some resistance mutations reduced growth rate and could carry a fitness penalty in pathogens. However, certain changes involving G37 and L198 carry little or no growth penalty and may pose the greatest risk for resistance development in the field. © 2022 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

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Abstract Background Mutations in an enzyme target are one of the most common mechanisms whereby antibiotic resistance arises. Identification of the resistance mutations in bacteria is essential for understanding the structural basis of antibiotic resistance and design of new drugs. However, the traditionally used experimental approaches to identify resistance mutations were usually labor-intensive and costly. Results We present a machine learning (ML)-based classifier for predicting rifampicin (Rif) resistance mutations in bacterial RNA Polymerase subunit β (RpoB). A total of 186 mutations were gathered from the literature for developing the classifier, using 80% of the data as the training set and the rest as the test set. The features of the mutated RpoB and their binding energies with Rif were calculated through computational methods, and used as the mutation attributes for modeling. Classifiers based on five ML algorithms, i.e. decision tree, k nearest neighbors, naïve Bayes, probabilistic neural network and support vector machine, were first built, and a majority consensus (MC) approach was then used to obtain a new classifier based on the classifications of the five individual ML algorithms. The MC classifier comprehensively improved the predictive performance, with accuracy, F-measure and AUC of 0.78, 0.83 and 0.81for training set whilst 0.84, 0.87 and 0.83 for test set, respectively. Conclusion The MC classifier provides an alternative methodology for rapid identification of resistance mutations in bacteria, which may help with early detection of antibiotic resistance and new drug discovery.

• UV-aged polystyrene was more conducive to biofilm formation than pristine PS. • Biofilm on UV aged PS had more resistance mutations than that on pristine PS. • Ery enhanced biofilm formation and resistance mutations on PS microplastics. • UV aging and Ery repressed rpoS, mutS , and uvrD expressions in biofilm bacteria. Microplastics (MPs) and antibiotics co-occur widely in the environment and pose combined risk to microbial communities. The present study investigated the effects of erythromycin on biofilm formation and resistance mutation of a model bacterium, E. coli , on the surface of pristine and UV-aged polystyrene (PS) MPs sized 1–2 mm. The properties of UV-aged PS were significantly altered compared to pristine PS, with notable increases in specific surface area, carbonyl index, hydrophilicity, and hydroxyl radical content. Importantly, the adsorption capacity of UV-aged PS towards erythromycin was approximately 8-fold higher than that of pristine PS. Biofilms colonizing on UV-aged PS had a greater cell count (5.6 × 108 CFU mg−1) and a higher frequency of resistance mutation (1.0 × 10−7) than those on pristine PS (1.4 × 108 CFU mg−1 and 1.4 × 10−8, respectively). Moreover, erythromycin at 0.1 and 1.0 mg L −1 significantly (p < 0.05) promoted the formation and resistance mutation of biofilm on both pristine and UV-aged PS. DNA sequencing results confirmed that the biofilm resistance was attributed to point mutations in rpoB segment of the bacterial genome. qPCR results demonstrated that both UV aging and erythromycin repressed the expression levels of a global regulator rpoS in biofilm bacteria, as well as two DNA mismatch repair genes mutS and uvrD , which was likely to contribute to increased resistance mutation frequency. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract Background For the advancement of cancer research, the collection of tissue specimens from drug‐resistant tumors after targeted therapy is crucial. Although patients with lung cancer are often provided targeted therapy, post‐therapy specimens are not routinely collected due to the risks of collection, limiting the study of targeted therapy resistance mechanisms. Posthumous rapid tissue donation (RTD) is an expedient collection process that provides an opportunity to understand treatment‐resistant lung cancers. Methods Consent to participate in the thoracic RTD protocol was obtained during patient care. When death occurred, tumor and paired non‐tumor, cytology, and blood specimens were collected within 48 hours and preserved as formalin‐fixed and frozen specimens. Tissue sections were evaluated with hematoxylin and eosin staining and immunohistochemistry (IHC) against multiple biomarkers, including various programmed death ligand 1 (PD‐L1) clones. Next‐generation sequencing was performed on 13 specimens from 5 patients. Results Postmortem specimens (N = 180) were well preserved from 9 patients with lung cancer. PD‐L1 IHC revealed heterogeneity within and between tumors. An AGK‐BRAF fusion was newly identified in tumor from a donor with a known echinoderm microtubule‐associated protein‐like 4 to anaplastic lymphoma kinase (EML4‐ALK) fusion and history of anaplastic lymphoma kinase (ALK) inhibitor therapy. RNA expression analysis revealed a clonal genetic origin of metastatic cancer cells. Conclusions Post‐therapy specimens demonstrated PD‐L1 heterogeneity and an acyl glycerol kinase to B‐rapidly accelerated fibrosarcoma (AGK‐BRAF) fusion in a patient with an EML4‐ALK–positive lung adenocarcinoma as a potential resistance mechanism to ALK inhibitor therapy. Rapid tissue donation collection of postmortem tissue from lung cancer patients is a novel approach to cancer research that enables studies of molecular evolution and drug resistance.

In non-small cell lung cancer (NSCLC), identifying the presence of sensitizing and resistance epidermal growth factor receptor (EGFR) mutations dictates treatment plans. Extracellular vesicles (EVs) are emerging as abundant, stable potential liquid biopsy targets that offer the potential to quantify EGFR mutations in NSCLC patients at the RNA and protein level at multiple points through treatment. In this study, we present a systematic approach for serial mutation profiling of 34 EV samples from 10 metastatic NSCLC patients with known EGFR mutations through treatment. Using western blot and droplet digital PCR (ddPCR), sensitizing (exon 19 deletion, L858R) mutations were detected in EV-Protein, and both sensitizing and resistance (T790M) mutations were quantified in EV-RNA. EGFR mutations were detected in EV-Protein from four patients at multiple time points through treatment. Using EV-RNA, tumor biopsy matched sensitizing mutations were detected in 90% of patients and resistance mutations in 100% of patients. Finally, mutation burden in EV-RNA at each time point was compared to disease status, described as either stable or progressing. For 6/7 patients who were longitudinally monitored through treatment, EV mutation burden mirrored clinical trajectory. When comparing mutation detection between EV-RNA and ctDNA using ddPCR, EVs had a better detection rate for exon 19 deletions and the L858R point mutation. In conclusion, this study demonstrates that integrating EV analysis into liquid biopsy mutation screening has the potential to advance beyond the current standard of care “rule in” test. The multi-analyte testing allows future integration of EGFR mutation monitoring with additional EV-markers for a comprehensive patient monitoring biomarker.

Since the first clinical report in 2013, inhibitors of the intracellular kinase BTK (BTKi) have profoundly altered the treatment paradigm of B cell malignancies, replacing chemotherapy with targeted agents in patients with chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), and Waldenström's macroglobulinemia. There are over 20 BTKi, both irreversible and reversible, in clinical development. While loss-of-function (LoF) mutations in the BTK gene cause the immunodeficiency X-linked agammaglobulinemia, neither inherited, nor somatic BTK driver mutations are known. Instead, BTKi-sensitive malignancies are addicted to BTK. BTK is activated by upstream surface receptors, especially the B cell receptor (BCR) but also by chemokine receptors, and adhesion molecules regulating B cell homing. Consequently, BTKi therapy abrogates BCR-driven proliferation and the tissue homing capacity of the malignant cells, which are being redistributed into peripheral blood. BTKi resistance can develop over time, especially in MCL and high-risk CLL patients. Frequently, resistance mutations affect the BTKi binding-site, cysteine 481, thereby reducing drug binding. Less common are gain-of-function (GoF) mutations in downstream signaling components, including phospholipase Cγ2 (PLCγ2). In a subset of patients, mechanisms outside of the BCR pathway, related e.g. to resistance to apoptosis were described. BCR signaling depends on many proteins including SYK, BTK, PI3K; still based on the resistance pattern, BTKi therapy only selects GoF alterations in the NF-κB arm, whereas an inhibitor of the p110δ subunit of PI3K instead selects resistance mutations in the RAS-MAP kinase pathway. BTK and PLCγ2 resistance mutations highlight BTK's non-redundant role in BCR-mediated NF-κB activation. Of note, mutations affecting BTK tend to generate clone sizes larger than alterations in PLCγ2. This infers that BTK signaling may go beyond the PLCγ2-regulated NF-κB and NFAT arms. Collectively, when comparing the primary and acquired mutation spectrum in BTKi-sensitive malignancies with the phenotype of the corresponding germline alterations, we find that certain observations do not readily fit with the existing models of BCR signaling. [ABSTRACT FROM AUTHOR]

Varroa destructor is the most common ectoparasite of the Western honey bee (Apis mellifera L.) worldwide and poses a serious threat to bee health. Synthetic acaricides, particularly pyrethroids, are frequently used to control Varroa mites. However, long-term and repeated use of synthetic pyrethroids has led to the development of resistance. In this study, we report on the presence of resistance mutations in the voltage-gated sodium channel in V. destructor populations from Turkish beekeeping areas. Two resistance mutations, L925V and L925I, that were previously associated with pyrethroid resistance, were found in more than 75% of the populations. A general correlation between the presence of mutations and the history of acaricide usage was observed for the sampled hives. In addition, we show there is only a low genetic distance among the sampled V. destructor populations, based on the analysis of three mitochondrial genes: cytochrome b (cytb), ATP synthase subunit 6 (atp6), and cytochrome c oxidase subunit III (cox3). Revealing the presence and geographical distribution of pyrethroid resistance mutations in V. destructor populations from Turkish apiaries will contribute to create more effective mite management programmes. [ABSTRACT FROM AUTHOR]

Background: Mutations in an enzyme target are one of the most common mechanisms whereby antibiotic resistance arises. Identification of the resistance mutations in bacteria is essential for understanding the structural basis of antibiotic resistance and design of new drugs. However, the traditionally used experimental approaches to identify resistance mutations were usually labor-intensive and costly. Results: We present a machine learning (ML)-based classifier for predicting rifampicin (Rif) resistance mutations in bacterial RNA Polymerase subunit β (RpoB). A total of 186 mutations were gathered from the literature for developing the classifier, using 80% of the data as the training set and the rest as the test set. The features of the mutated RpoB and their binding energies with Rif were calculated through computational methods, and used as the mutation attributes for modeling. Classifiers based on five ML algorithms, i.e. decision tree, k nearest neighbors, naïve Bayes, probabilistic neural network and support vector machine, were first built, and a majority consensus (MC) approach was then used to obtain a new classifier based on the classifications of the five individual ML algorithms. The MC classifier comprehensively improved the predictive performance, with accuracy, F-measure and AUC of 0.78, 0.83 and 0.81for training set whilst 0.84, 0.87 and 0.83 for test set, respectively. Conclusion: The MC classifier provides an alternative methodology for rapid identification of resistance mutations in bacteria, which may help with early detection of antibiotic resistance and new drug discovery. [ABSTRACT FROM AUTHOR]

Background: Brigatinib is a potent ROS1 inhibitor. The existing data on its clinical activity in ROS1-rearranged non-small cell lung cancer (NSCLC) are limited to four cases. Methods: Six patients with ROS1-rearranged advanced NSCLC treated with brigatinib were identified through search of the internal databases of four participating cancer centers. Four additional patients were selected by PubMed and Google Scholar search. The objective response rate (ORR), progression-free survival (PFS) (RECIST v.1.1), duration of treatment (DOT), and safety were assessed. Results: Of eight patients evaluable for response assessment (crizotinib naive-1, crizotinib resistant -7), three patients demonstrated a partial response (ORR-37%). One crizotinib-naive patient had an ongoing response at 21.6 months. Of seven crizotinib-resistant patients, two patients demonstrated a partial response (ORR-29%), and one patient (14%) had stable disease. PFS, available in four crizotinib-resistant patients, was 7.6 + , 2.9, 2.0, and 0.4 months. In crizotinib-resistant patients, DOT was 9.7 + , 7.7 + , 7.6 + , 4.0, 2.0, 1.1, 0.4 months, and was not reported in two patients. Genomic profiling in one responder revealed no ROS1 alteration, suggesting that the response was attributable to "off-target" brigatinib activity. In two patients with progressive disease, genomic profiling demonstrated a cMET exon 14 mutation + KRAS G12A mutation in one case, and a persisting ROS1-CD74 fusion + TP53 K139N, FGFR2 E250G, ATM G2695D, and NF1 R2258Q mutations in the other. No grade 3–5 toxicity was observed. Conclusion: Brigatinib demonstrated modest activity in crizotinib-resistant ROS1-rearranged NSCLC. Its intracranial and systemic activity should be assessed in correlation with the underlying molecular mechanism of crizotinib resistance. Plain Language Summary: Our series is the first to describe brigatinib activity in ROS1-altered NSCLC. In crizotinib-resistant patients, ORR with brigatinib was 29%. PFS with brigatinib was 7.6+, 2.9, 2.0, and 0.4 months. DOT with brigatinib was 9.7+, 7.7+, 7.6+, 4.0, 2.0, 1.1, 0.4 months. The correlation between response and molecular resistance needs further exploration. [ABSTRACT FROM AUTHOR]

Transmitted drug resistance (TDR) in treatment-naive HIV patients can contribute to failure of initial antiretroviral therapy. In Korea, there has been a gradual increase in TDR, but the recent increase in the use of integrase strand transfer inhibitors (INSTIs) could affect TDR trends and INSTI resistance mutations. We evaluated the patterns of TDR in newly diagnosed HIV patients over time from 2011 to 2019. We analyzed the genotypic resistance of strains in 336 patients and sequenced the integrase gene in 71 among 336 subjects. The overall prevalence of TDR was 5.9% (20 of 336 patients), and it showed a tendency to increase over time (5.1% in 2011–2013, 6.1% in 2014–2016, and 7.2% in 2017–2019; p = .3018). Furthermore, non-nucleoside reverse transcriptase inhibitor resistance showed a marginally significant increase over time (1.45% in 2011–2013, 3.48% in 2014–2016, and 6.02% in 2017–2019; p = .0505). Regarding transmitted INSTI resistance mutation, there were no major INSTI resistance mutations but several accessory INSTI resistance mutations and predominant natural polymorphisms. This study shows several significant changes in TDR and suggests the importance of continuous surveillance of TDR and genetic variation in the integrase region. [ABSTRACT FROM AUTHOR]

Human cytomegalovirus (HCMV) is the most frequent cause of opportunistic viral infection following transplantation. Viral factors of potential clinical importance include the selection of mutants resistant to antiviral drugs and the occurrence of infections involving multiple HCMV strains. These factors are typically addressed by analyzing relevant HCMV genes by PCR and Sanger sequencing, which involves independent assays of limited sensitivity. To assess the dynamics of viral populations with high sensitivity, we applied high-throughput sequencing coupled with HCMV-adapted target enrichment to samples collected longitudinally from 11 transplant recipients (solid organ, n = 9, and allogeneic hematopoietic stem cell, n = 2). Only the latter presented multiple-strain infections. Four cases presented resistance mutations (n = 6), two (A594V and L595S) at high (100%) and four (V715M, V781I, A809V, and T838A) at low (<25%) frequency. One allogeneic hematopoietic stem cell transplant recipient presented up to four resistance mutations, each at low frequency. The use of high-throughput sequencing to monitor mutations and strain composition in people at risk of HCMV disease is of potential value in helping clinicians implement the most appropriate therapy. [ABSTRACT FROM AUTHOR]

The phase transition properties of MgSb/Sb multilayer thin films were studied systematically. After composited with MgSb layer, MgSb/Sb thin film had better amorphous stability and higher resistance. One-dimensional growth dominated mechanism made MgSb/Sb have ultra-fast phase change speed. The grain growth and interface stress resulted in a little change on surface morphology during crystallization. The multilayer structure was confirmed by element distribution on cross section. The reversible resistance switching was achieved on [MgSb(7 nm)/Sb(3 nm)]5-based device. This work showed that MgSb/Sb multilayer film was a potential material with fast speed and low power consumption for phase change memory application. [ABSTRACT FROM AUTHOR]

Background: For the advancement of cancer research, the collection of tissue specimens from drug‐resistant tumors after targeted therapy is crucial. Although patients with lung cancer are often provided targeted therapy, post‐therapy specimens are not routinely collected due to the risks of collection, limiting the study of targeted therapy resistance mechanisms. Posthumous rapid tissue donation (RTD) is an expedient collection process that provides an opportunity to understand treatment‐resistant lung cancers. Methods: Consent to participate in the thoracic RTD protocol was obtained during patient care. When death occurred, tumor and paired non‐tumor, cytology, and blood specimens were collected within 48 hours and preserved as formalin‐fixed and frozen specimens. Tissue sections were evaluated with hematoxylin and eosin staining and immunohistochemistry (IHC) against multiple biomarkers, including various programmed death ligand 1 (PD‐L1) clones. Next‐generation sequencing was performed on 13 specimens from 5 patients. Results: Postmortem specimens (N = 180) were well preserved from 9 patients with lung cancer. PD‐L1 IHC revealed heterogeneity within and between tumors. An AGK‐BRAF fusion was newly identified in tumor from a donor with a known echinoderm microtubule‐associated protein‐like 4 to anaplastic lymphoma kinase (EML4‐ALK) fusion and history of anaplastic lymphoma kinase (ALK) inhibitor therapy. RNA expression analysis revealed a clonal genetic origin of metastatic cancer cells. Conclusions: Post‐therapy specimens demonstrated PD‐L1 heterogeneity and an acyl glycerol kinase to B‐rapidly accelerated fibrosarcoma (AGK‐BRAF) fusion in a patient with an EML4‐ALK–positive lung adenocarcinoma as a potential resistance mechanism to ALK inhibitor therapy. Rapid tissue donation collection of postmortem tissue from lung cancer patients is a novel approach to cancer research that enables studies of molecular evolution and drug resistance. [ABSTRACT FROM AUTHOR]

Sidelcina Rugieri Pacheco,1 Maria Isabel Magalhães Andrade dos Santos,1 Andreas Stocker,2 Maria Alice Sant’Anna Zarife,3 Maria Isabel Schinoni,2 Raymundo Paraná,2 Mitermayer Galvão dos Reis,1 Luciano Kalabric Silva1 1Laboratory of Pathology and Molecular Biology, Research Site Gonçalo Muniz, Foundation Oswaldo Cruz (CPqGM/Fiocruz-BA), 2Federal University of Bahia, 3Central Laboratory of Public Health of Bahia (LACEN-BA), Salvador, Brazil Background and aims: Resistance mutation analogs to nucleos(t)ides have been described in treatment-naïve patients with chronic hepatitis B (CHB), with clinical implications. The aim of this study was to investigate primary resistance mutations and genotypes circulating in patients naïve to chronic hepatitis B, in the Northern and Northeastern regions of Brazil.Methods: We conducted a study of resistance mutations and genotypic characterization of hepatitis B virus (HBV) in 189 treatment-naïve patients chronically infected with HBV.Results: Drug resistance-associated mutations located in the RT domain of the P gene (rtHBV) were found in 6% of the treatment-naïve patients from the Northeastern Region. The mutations were rtA194T, rtL180M + rtM204V, rtS202I, rtM204I, and rtA181S. No patient in the Northern Region had the resistance mutation. In the gene S region, the frequency of vaccine escape mutations was 2.4% in the Northeastern Region and 8.6% in the Northern Region.Conclusion: This information before the start of treatment may contribute to clinical decision making, reducing treatment failure and the risk of progression to cirrhosis and hepatocellular carcinoma for CHB. Keywords: Northeast, North, Brazil, direct sequencing, treatment failure

HIV-1 resistance to antiretroviral therapy (ART) is a crucial issue, despite various effective drugs are available for the treatment. Although the viral RNA is suppressed below the detection limit (

Importance: This observation provides comprehensive data on the clinical correlates of both cytomegalovirus (CMV) genotypic follow-up and clinical monitoring and outcomes for two different solid organ transplantation recipients that received letermovir as secondary prophylaxis. Our study emphasizes that monitoring of CMV disease in the patient and early genotypic detection of resistance mutations are essential when using new antiviral drugs for off-label indication in patients experiencing CMV relapses or not responding to standard antiviral therapy. These cases and the bibliography reviewed can be helpful for other researchers and clinicians working in the field to optimize the use of new treatments for transplant recipients since drug-resistant CMV infection is an important emerging problem even with new developments in antiviral treatment., Competing Interests: The authors declare no conflict of interest.

In this study, we examined the occurrence of acquired and transmitted drug resistance to integrase strand transfer inhibitor (INSTI) in HIV-1 strains in Chongqing (China) for guiding for the routine testing of INSTI-associated HIV-1 genotype resistance. Plasma samples were obtained from HIV-1 patients at Chongqing Public Health Medical Center from July 2019 to August 2022. Besides, amplification, sequence, and analysis of the portion of the HIV-1 pol gene that encodes the integrase protein were implemented to identify INSTI resistance. Integrase sequence data was harvested for a comprehensive cohort of 1032 patients infected with HIV-1. This cohort consisted of 564 ART-naive patients, 465 ART-treated patients, and 3 patients with an unknown treatment history. Within the study group, we identified INSTI resistance in 21 patients (2.03%, 21/1032), including 17 ART-treated patients (3.66%, 17/465). Among the ART-treated patients, 12 were INSTI-treated (11.76%, 12/102), 5 were INSTI-naive (1.38%, 5/363), and 4 were ART-ineffective patients (0.71%, 4/564). The prevalent major resistance mutation was Q148R (0.48%, 5/1032), while the most prevalent accessory resistance mutation was E157Q (1.65%, 17/1032). In light of the above, it is recommended that the incidence of accessory genotype analysis should be considered before starting any future INSTI-based therapy, especially in patients with drug resistance to NRTIs and NNRTIs and the reduction of INSTI sensitivity should be carefully monitored and investigated. Regular monitoring for resistance should be implemented after the use of INSTIs, and, importantly, ongoing monitoring of the decreasing susceptibility to INSTIs is crucial following the initiation of treatment with INSTIs.

Background/purpose: As a major causative pathogen of community-acquired pneumonia, Mycoplasma pneumoniae (M. pneumoniae) can cause both upper and lower respiratory tract inflammation as well as extrapulmonary syndromes, especially in infants and the elderly. The emergence of macrolide-resistance has significant effects on the treatment of relevant diseases in children. This study aimed to analyze the genotypes and the macrolide resistance-associated mutations in M. pneumoniae sampled from the pediatric patients in Henan, China., Methods: A segment of gene on the 23S rRNA was amplified and sequenced to detect the mutations related to macrolide resistance. Molecular typing was performed by the method named multiple locus variable-number tandem repeat analysis (MLVA) for macrolide-susceptible and macrolide-resistant specimens., Results: Among the M. pneumoniae-positive samples, 95.7% (111/116) had macrolide-resistant mutation, and all of them consisted of the A2063G mutation. There were only two MLVA types identified in this study, type 4-5-7-2 (51/92, 55.4%) and type 3-5-6-2 (41/92, 44.6%)., Conclusion: There was no correlation between MLVA types and macrolide resistance (P ​> ​0.05)., (Copyright © 2023 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)

The association between hepatitis B virus (HBV) quasispecies (QS) and the efficacy of nucleos(t)ide analog therapy is currently not well defined, particularly in the case of lamivudine (LAM)/adefovir (ADV) combination rescue therapy for patients with chronic HBV infection (CHB) presenting with LAM resistance. In the present study, 16 CHB patients with the rtM204I/V mutation in the tyrosine-methionine-aspartate-aspartate motif of the C domain of the polymerase gene who switched to LAM/ADV treatment due to LAM resistance were assessed. HBV DNA was isolated from these patients and the reverse transcriptase (RT) region was sequenced. The QS heterogeneity and distribution was analyzed, the mutation sites were recorded and the phylogenetic trees were constructed. The results indicated that QS heterogeneity and distribution in the RT and S regions were not significantly different between responders (RS) and non-RS (NRS) at baseline (P>0.05), except for the higher frequency of a dominant strain in the RT region at the nucleotide level in the RS group (P=0.039). In addition, in NRS, no significant difference in QS heterogeneity or distribution in these regions was identified at six months vs. the baseline. Furthermore, although in the non-responder group the frequency of the LAM resistance-associated mutations (rtM204V/I) decreased at 6 months compared with the baseline, it did not disappear in any of the patients after six months of treatment. Analysis of individual patients did not indicate any consistent selection of specific HBV mutants during LAM/ADV rescue therapy. In conclusion, the baseline HBV QS within the RT and S regions may not be a valid predictor of the response to LAM/ADV rescue treatment in CHB patients with LAM resistance. [ABSTRACT FROM AUTHOR]

Updated guidelines for the treatment of antiretroviral therapy (ART)-negative patients with HIV recommend integrase strand transfer inhibitor (INSTI)-based regimens. HIV patients are tested for resistance to antiretrovirals, and the reported prevalence of transmitted INSTI resistance remains rare worldwide. However, no data related to INSTI resistance in Korean HIV patients have been reported. We aimed to determine the prevalence of INSTI resistance-related mutations in South Korea. We subjected both ART-naive (n = 58) and ART-experienced Korean HIV patients (n = 41) to genotypic resistance analysis and determined a prevalence of INSTI major resistance mutations of 3.4% (n = 2) among ART-naive patients and 22.0% (n = 9) among ART-experienced patients. In the former group, both major INSTI resistance cases involved the nonpolymorphic E92Q mutation in the integrase strand. Our findings suggest that INSTI resistance testing should be included in the standard resistance screening protocols for Korean HIV patients. [ABSTRACT FROM AUTHOR]

Kinase inhibitors (KI) have dramatically improved the outcome of treatment in patients with non-small cell lung cancer (NSCLC), which harbors an oncogene addiction. This study assesses KI plasma levels and their clinical relevance in patients chronically exposed to KIs. Plasma samples were collected in NSCLC patients receiving erlotinib, gefitinib, osimertinib, crizotinib, or dabrafenib (with or without trametinib) for at least three months between November 2013 and February 2019 in a single institution. KI drug concentrations were measured by ultra-performance liquid chromatography coupled with tandem mass spectrometry and compared to published data defining optimal plasma concentration. The main outcome was the rate of samples with suboptimal KI plasma concentrations. Secondary outcomes included its impact on T790M mutation emergence in patients receiving a first-generation epidermal growth factor receptor (EGFR) KI. Fifty-one samples were available from 41 patients with advanced NSCLC harboring driver genetic alterations, including EGFR, v-Raf murine sarcoma viral oncogene homolog B (BRAF), anaplastic lymphoma kinase (ALK) or ROS proto-oncogene 1 (ROS1), and who had an available evaluation of chronic KI plasma exposure. Suboptimal plasma concentrations were observed in 51% (26/51) of cases. In EGFR-mutant cases failing first-generation KIs, EGFR exon 20 p.T790M mutation emergence was detected in 31% (4/13) of samples in optimal vs. none in suboptimal concentration (0/5). Suboptimal plasma concentrations of KIs are frequent in advanced NSCLC patients treated with a KI for at least three months and might contribute to treatment failure.

Mongolia has a high prevalence of Helicobacter pylori infection and the second highest incidence of gastric cancer worldwide. Thus, investigating the prevalence of antibiotic resistance and its underlying genetic mechanism is necessary. We isolated 361 H. pylori strains throughout Mongolia. Agar dilution assays were used to determine the minimum inhibitory concentrations of five antibiotics; amoxicillin, clarithromycin, metronidazole, levofloxacin, and minocycline. The genetic determinants of antibiotic resistance were identified with next-generation sequencing (NGS) and the CLC Genomics Workbench. The resistance to metronidazole, levofloxacin, clarithromycin, amoxicillin, and minocycline was 78.7%, 41.3%, 29.9%, 11.9% and 0.28%, respectively. Multidrug resistance was identified in 51.3% of the isolates investigated which were further delineated into 9 antimicrobial resistance profiles. A number of known antibiotic resistance mutations were identified including rdxA, frxA (missense, frameshift), gyrA (N87K, A88P, D91G/N/Y), 23S rRNA (A2143G), pbp1A (N562Y), and 16S rRNA (A928C). Furthermore, we detected previously unreported mutations in pbp1A (L610*) and the 23S rRNA gene (A1410G, C1707T, A2167G, C2248T, and C2922T). The degree of antibiotic resistance was high, indicating the insufficiency of standard triple therapy in Mongolia.