Predicting and overcoming resistance to CDK9 inhibitors for cancer therapy

Abnormally activated CDK9 participates in the super-enhancer mediated transcription of short-lived proteins required for cancer cell survival. Targeting CDK9 has shown potent anti-tumor activity in clinical trials among different cancers. However, the study and knowledge on drug resistance to CDK9 inhibitors are very limited. In this study, we established an AML cell line with acquired resistance to a highly selective CDK9 inhibitor BAY1251152. Through genomic sequencing, we identified in the kinase domain of CDK9 a mutation L156F, which is also a coding SNP in the CDK9 gene. By knocking in L156F into cancer cells using CRISPR/Cas9, we found that single CDK9 L156F could drive the resistance to CDK9 inhibitors, not only ATP competitive inhibitor but also PROTAC degrader. Mechanistically, CDK9 L156F disrupts the binding with inhibitors due to steric hindrance, further, the mutation affects the thermal stability and catalytic activity of CDK9 protein. To overcome the drug resistance mediated by the CDK9-L156F mutation, we discovered a compound, IHMT-CDK9-36 which showed potent inhibition activity both for CDK9 WT and L156F mutant. Together, we report a novel resistance mechanism for CDK9 inhibitors and provide a novel chemical scaffold for the future development of CDK9 inhibitors.

HIV-1 genetic characteristics and drug resistance in newly diagnosed population in Baoding city of Hebei Province / 中华微生物学和免疫学杂志

Objective:To investigate the distribution of HIV-1 genotypes and drug resistance in newly diagnosed HIV-1 patients in Baoding in 2020.Methods:A self-developed method was used to amplify the pol gene sequence of HIV-1, and the sequencing results were analyzed by phylogenetic analysis and compared with the Stanford drug resistance database to determine the HIV-1 subtypes and gene mutations. Results:A total of 96 patients with HIV-1 infection were recruited in this study, and 83 pol gene sequences were successfully obtained. In the study population, 88 (91.7%) were male with an average age of 39 years and 54 (56.3%) were married. Most of the patients were infected through sexual contact (95.8%, 92/96), and 75.0% (72/96) were through homosexual transmission. Phylogenetic analysis showed that various HIV-1 subtypes were detected and among them, CRF01_AE (51.8%, 43/83), CRF07_BC (24.1%, 20/83) and B subtype (10.8%, 9/83) were the most epidemic strains. Moreover, the subtypes of newly identified recombinant strains in recent years accounted for 13.3% (11/83). Drug resistance test results showed that the pre-treatment drug resistance rate in newly diagnosed HIV-1 patients was 8.4% (7/83), and the drug resistance rates to protease inhibitor (PIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs) and integrase inhibitors (INIs) were 3.6% (3/83), 1.2% (1/83) and 3.6% (3/83), respectively. Conclusions:The HIV-1 subtypes in the newly diagnosed population in Baoding in 2020 were complex and diverse. There were many unique recombinant strains and drug-resistant strains. Therefore, it was necessary to strengthen drug resistance monitoring as well as the prevention and control of HIV-1 infection in this area.

Phenotypic resistance properties of HIV-1 CRF01_AE strain main drug resistance mutations to integrase inhibitors / 中华微生物学和免疫学杂志

Objective:To analyze the effects of the main drug resistance mutations in the integrase (IN) region on the resistance of HIV-1 CRF01_AE strains, and compare the differences with subtype B strains.Methods:Seven IN region mutations or combined mutations (T66K, F121Y, Q148K, N155H, G118R, R263K, Q148K/N155H) were selected from the HIV drug resistance database of Stanford University in the United States, and introduced to the IN region of HIV-1 B subtype infectious clone pNL4-3 and CRF01_AE infectious clone pGX002 by seamless cloning, homologous recombination and point mutation. The mutant plasmids were transfected into 293T cells for virus packaging. The culture was expanded in MT2 cells and infectious titers were detected. Half maximal inhibitory concentrations (IC 50) of four integrase inhibitors (INSTIs), raltegravir (RAL), elvitegravir (EVG), dolutegravir (DTG) and bictegravir (BIC), against 14 mutant viruses were detected and compared with the IC 50 against the wild-type viruses. Results:B subtype and CRF01_AE plasmids carrying seven IN region mutations or combined mutations were successfully constructed, and 14 recombinant viruses were packaged with an infectious titer of 10 4-10 6 median tissue culture infective dose (TCID 50)/ml. The recombinant viruses replicated efficiently in MT2 cells. The concentrations of HIV-1 p24 antigen contained in the supernatants of cell culture reached 830-2 700 ng/ml. Five mutations or combined mutations (T66K, F121Y, Q148K, N155H, Q148K/N155H) caused CRF01_AE and B subtype strains to be highly resistant to RAL and EVG, resulting in an increase in the IC 50 by 200 times and 2 000 times or more as compared with the IC 50 against the wild-type viruses. The same mutation-caused fold changes of IC 50 of RAL and EVG against CRF01_AE were significantly lower than that of subtype B ( P<0.01). Q148K/N155H mutation caused B subtype and CRF01_AE to be highly resistant to DTG and BIC, with IC 50 increased by more than 50 times. Other mutations had little effects on the sensitivity to DTG and BIC. Conclusions:Fourteen HIV-1 strains carrying seven INSTI resistance mutations based on B subtype and CRF01_AE were constructed. Five mutations resulted in high resistance to RAL and EVG, and there was a high level of cross-resistance. Resistance to RAL and EVG caused by the same mutation was higher in B subtype than in CRF01_AE. The combined mutation of Q148K and N155H was associated with greater resistance to DTG and BIC, indicating that the genetic barrier of DTG and BIC resistance was high. DTG and BIC could effectively inhibit the strains carrying INSTI resistance mutations without obvious subtype difference.

HIV-1 genetic diversity and drug resistance mutations in the northern Brazilian region

ABSTRACT Brazil is a huge continental country with striking geographic differences which are well illustrated in the HIV/AIDS epidemic. Contrasting with the significant decline in the national AIDS detection rate in the last decade, a linear growth has been reported in the Northern region. Despite its public health and epidemiologic importance, there is scarce HIV-1 molecular data from Northern Brazil. This scoping review summarizes recent epidemiologic data with special emphasis on HIV-1 genetic diversity and antiretroviral drug resistance mutations in patients from the seven Northern states of Brazil. Studies from the Northern Brazil on different HIV-1 genomic regions, mostly pol (protease/reverse transcriptase) sequences of naïve/antiretroviral treated adults/children were retrieved from PubMed/MEDLINE electronic database. These studies indicate a consistent molecular profile largely dominated by HIV-1 subtype B with minor contribution of subtypes F1 and C and infrequent detection of other subtypes (A1, D, K), recombinants (BF1, BC), circulating recombinant forms (CRF) as the new CRF90_BF1 and CRF02_AG-like, CRF28-29_BF-like, CRF31_BC-like, and a potential new CRF_BF1. This pattern indicates a founder effect of subtype B and the introduction of non-B-subtypes and recombinants probably generated in the Southern/Southeastern regions. In naïve populations transmitted drug resistance (TDR) can impact the outcome of first-line antiretroviral treatment and prophylactic/preventive regimens. In the Northern region TDR rates are moderate while patients failing highly active antiretroviral therapy (HAART) showed high prevalence of acquired drug resistance mutations. The limited HIV-1 molecular data from Northern Brazil reflects the great challenges to generate comprehensive scientific data in isolated, underprivileged areas. It also highlights the need to invest in local capacity building which supported by adequate infrastructure and funding can promote robust research activities to help reduce the scientific asymmetries in the Northern region. Currently the impacts of the overwhelming COVID-19 pandemic on the expanding HIV/AIDS epidemic in Northern Brazil deserves to be closely monitored.

Research progress of HIV-1 drug resistance mutations / 中国人兽共患病学报

By the end of 2015,all over the world there were around 17 million HIV/AIDS cases received antiretroviral therapy,the HIV-1 morbidity and mortality decreased rapidly.With antiretroviral treatment to all HIV infected persons,HIV resistance mutation is also a threat to the long-term treatment and also,had a negative impact on the important public health strategy of the global elimination in 2030.This review attempts to proceed from different economic and geographical environment,describing genetic barrier of commonly used antiretroviral drugs,the degree of their cross-reactions,and the epidemiology and management of drug-resistant mutations from the individual and group levels.The paper also summarizes the prevalent modes of transmitted drug resistance (TDR) and acquired drug resistance (ADR) in both high-income and low-and middle-income countries (LMICs),and analyze the two kind problems of public health significance to HIV resistant mutations,i.e.pretreatment resistance (PDR) and preexposure prophylaxis (PREP).In addition,in view of effectivel HIV cases of treatment and management in different countries,this paper also analyzes the genotypic resistance testing and treatment practices related to AIDS prevention and control.The content has a certain reference function to our country.

Geolocalization of HIV-1 subtypes and resistance mutations of patients failing antiretroviral therapy in Salvador - Brazil

ABSTRACT Background: Geographical distribution of HIV variants is an important way to understand the circulation and spread of such viral strains. Objectives: To evaluate the spatial distribution of HIV-1 variants in patients failing antiretroviral therapy, in Salvador, Brazil. Methods: We performed a cross-sectional evaluation of HIV resistance test reports of patients who underwent genotyping tests in a referral center in Salvador, Brazil, for the years 2008-2014. The laboratory database contains around 2500 resistance reports of patients failing antiretroviral therapy. Genotypic tests were performed by sequencing of HIV-1 POL region (TrueGene, Siemens). We assessed HIV-1 resistance mutations and subtype, as well as residential address, age, and gender of patients. Results: We evaluated 1300 reports, 772 (59.4%) of them from male patients. As expected, subtype B predominated (79%) followed by subtypes F1 (6.7%) and BF (6.5%). The most frequent mutations in HIV-1 reverse transcriptase were 184V (79.1%), 41L (33.5%), 67N (30.4%), 103N (42.4%), and 108I (11.1%). Most frequent mutations in HIV-1 protease were 63P (52.4%), 36I (47.9%), 15 V (33.0%), 62 V (28.1%) and 13 V (25.8%). Some mutations (41L, 215Y, 210W) were significantly more frequent among men. We detected a significantly higher accumulation of 103N mutation in specific areas of Salvador. We identified a more restricted circulation pattern for subtype FB (more frequent in some regions), and F1 (almost absent in a specific region). Conclusion: Our results suggest that specific subtypes/resistance mutations present a distinct frequency rate in specific areas of Salvador, probably due to a restricted circulation pattern. This trend to clustering was observed in regions covered by AIDS referral centers, suggesting that pattern of care for such patients can interfere in virological outcomes.

Prevalence of mutations in HBV DNA polymerase gene associated with nucleos(t)ide resistance in treatment-naive patients with Chronic Hepatitis B in Central China

Abstract Objective There are a lot of disagreements in the studies on hepatitis B virus (HBV) DNA polymerase mutation rate associated with nucleos(t)ide analogues (NAs) in treatment-naive chronic hepatitis B (CHB) patients. This is the first study aimed to investigate the prevalence of spontaneous HBV resistance mutations in Central China. Methods This study included treatment-naive patients with CHB from June 2012 to May 2015 receiving care at the Institute of Liver Disease in Central China. All patients completed a questionnaire covering different aspects, such as family medical history, course of liver disease, medication history, alcohol use, among others. Mutations in HBV DNA polymerase associated with NAs resistance were detected using INNO-LiPA assay. Results 269 patients were infected with HBV genotype B (81.4%), C (17.9%), and both B and C (0.7%). Mutations in HBV DNA polymerase were detected in 24 patients (8.9%) including rtM204I/V (n = 6), rtN236T (n = 5), rtM250V (n = 2), rtL180M (n = 2), rtT184G (n = 1), rtM207I (n = 1), rtS202I (n = 1), rtM204V/I & rtL180M (n = 5), and rtM204I & rtM250V (n = 1). Conclusion Spontaneous HBV resistance mutations in HBV DNA polymerase were found in treatment-naive patients with CHB in Central China. These findings suggest that we should analyze HBV DNA polymerase resistance mutation associated with NAs before giving antiviral therapy such as lamivudine (LAM), adefovir (ADV), and telbivudine (LdT).

Hepatitis B virus genotypes and drug resistance mutation gene detection / 国际检验医学杂志

Objective To investigate the distribution of hepatitis B virus(HBV) genotypes ,drug resistance situation of hepatitis B patients and the relation between HBV genotype with drug resistance and mutation sites .Methods Three hundred serum samples of HBV patients were collected and HBV‐DNA was extracted by adopting the centrifugal column method .The HBV genotype and drug resistant mutant were detected by using PCR‐reverse dot blot hybridization method .Results In 300 cases of HBV‐DNA posi‐tive ,genotye B ,C ,B/C and other undetected genotypes were detected out ,but genotype D was not detected out ,in which genotype C was predominant ,accounting for 81 .8% ;in the HBV patients ,the resistant drugs were dominated by‐lamivudine and telbivudine , accounting for 43 .6% ;the HBV drug resistant mutation genotypes were mainly rt204I(24 .35% ) ,rt204V (17 .39% ) and rt180M (17 .39% );the drug resistance mutation rates of genotype B and C were 30 .77% and 42 .42% respectively ;the difference was sta‐tistically significant(P<0 .05) .Conclusion HBV genotype C in Dongying area is more than genotype B ,genotype C is prone to produce drug resistance ,rt204I ,rt204V and rt180M gene mutations are common ,lamivudine and telbivudine combined resistance is common ,the suitable treatment scheme should be selected according to genotyping and drug resistance mutations results .

Avaliação de mutações de resistência ao tratamento com análogos de nucleos(t)ídeos e de escape vacinal do vírus da hepatite B (VHB) em pacientes com hepatite crônica / Evaluation of treatment resistance mutations with nuclei analogues (t) ide and vaccine escape the hepatitis B virus (HBV) in patients with chronic hepatitis

INTRODUÇÃO: A hepatite B (VHB) é uma infecção dinâmica crônica, que apesar de existir programas de imunização e tratamento antiviral disponível, existe o risco de emergência de mutações de resistência aos análogos de núcleos(t)ídeos (AN) que devem ser rastreadas, devido as suas implicações clínicas. O Brasil disponibiliza pelo SUS cinco drogas para o tratamento antiviral: IFN, LAM, ADF, ETV e TDF e um guia de conduta clínica para orientar o tratamento no território nacional, o Protocolo de Diretrizes Terapêuticas para Hepatite B e co-infecções. OBJETIVO: O objetivo do presente estudo foi avaliar as mutações de resistência aos AN, mutações de escape vacinal e genótipos circulantes em pacientes com hepatite B crônica em dois centros de referencia em Hepatites, na Bahia (região Nordeste) e no Acre (região Norte) do Brasil. MATERIAL E MÉTODOS: Foi utilizadas ferramentas de biologia molecular e bioinformática, através de nested PCR e sequenciamento direto das amostras, para rastrear as mutações de resistência, a região alvo foi a transcriptase reversa (RT) do gene P e as mutações de escape vacinal foi a região do gene S do VHB, como também os genótipos e subgenotipos do VHB. RESULTADOS: Foram incluídos 527 pacientes durante o período de 2011-2015, sendo 320 pacientes do HUPES/BA e 207 do FUNDHACRE/AC. Os pacientes que representam a região Nordeste foram 59,3 % do sexo masculino e uma média de idade de 44,75±12,4 DP, os pacientes da região Norte 42% foram do sexo masculino e a média de idade foi de 40,36±13,9 DP. Todos os pacientes incluídos apresentaram AgHBs persistente por mais de seis meses e 86,1% apresentaram AgHBe negativo. Foram sequenciadas 296 amostras dos pacientes com VHB crônica. Foram encontradas mutações de resistência aos AN na Região Norte 1,2% (2), Região Nordeste 7,4%(8) e no global 3,8%(20). Os padrões de mutações de resistência primária encontrados foram: rtA194T, (3) rtL180M+M204V, rtL180M+M204I, rtS202I, rtM204I, rtA181S, rtA181E e rtA184S. Em relação ao escape vacinal a frequencia para a Região Norte foi de 7,1% (11), Região Nordeste 8,4% (9) e no global 7,6% (20). Nos pacientes virgens de tratamento (n=189), a frequência de mutações de resistência foi de 6%, somente nas amostras da região Nordeste. Não houve diferença estatisticamente significante entre o grupo com ou sem mutação dos pacientes virgens de tratamento. Não foram encontradas mutações de resistência nas amostras da região Norte. Os genótipos circulantes nas duas regiões foram A, D e F, e a região Nordeste foi encontrada o genótipo C (C2). CONCLUSÃO: Os resultados demonstram a importância de rastrear e monitorar as mutações de resistência aos AN e de escape vacinal devido a importância epidemiológica e clínica na conduta terapêutica.

INTRODUTION: Hepatitis B virus (HBV) is a chronic dynamic infection, which although there immunization programs and antiviral therapy available, there is a risk of emergence of resistance mutations cores analogs (t) ide to be screened, because of their implications clinics. The Brazil offers the SUS five drugs for antiviral treatment: IFN, LAM, ADF, ETV and TDF and clinical guide of conduct to guide treatment in the country, the Therapeutic Guidelines Protocol for Hepatitis B and coinfections. AIM: The aim of this study was to evaluate the resistance mutations core analogues (t) ide, vaccine escape mutations and circulating genotypes in patients with chronic hepatitis B in two reference centers in Hepatitis, Bahia (Northeast) and Acre (Northern region) of Brazil. MATERIAL AND METHODS: Was used tools of molecular biology and bioinformatics by nested PCR and direct sequencing of samples to track resistance changes, the target region is the reverse transcriptase (RT) P gene and vaccine escape mutations was region of the gene S of HBV, as well as the HBV genotypes and subgenotipos. RESULTS: 527 patients were included during the period 2011-2015, with 320 patients HUPES / BA and 207 FUNDHACRE / AC. Patients representing the Northeast were 59.3% male and an average age of 44.75 ± 12.4 PD patients in the northern region 42% were male and the average age was 40, 36 ± 13.9 DP. All patients had persistent HBsAg for more than six months and 86.1% were HBeAg negative. We were sequenced 296 samples from patients with chronic HBV. the cores of similar resistance mutations were found (t) ide in the North 1.2% (2), Northeast 7.4% (8) and 3.8% overall (20). The patterns of primary resistance mutations were: rtA194T (3) rtL180M + M204V, M204I + rtL180M, rtS202I, rtM204I, rtA181S, and rtA181E rtA184S. Regarding vaccine escape the frequency for the Northern Region was 7.1% (11), Northeast 8.4% (9) and the global 7.6% (20). In treatment-naïve patients (n = 189), the frequency of resistance mutations was 6%, only the samples in the Northeast. There was no statistically significant difference between the groups with or without mutation of naive patients. There were no resistance mutations in samples from the North. Circulating genotypes in the two regions A, D and F, and the Northeast found the C genotype (C2). CONCLUSION: The results demonstrate the importance of tracking and monitoring the resistance mutations similar cores (t) ide and vaccine escape due to epidemiological and clinical importance in the therapeutic approach.

Microarray-based genotyping and detection of drug-resistant HBV mutations from 620 Chinese patients with chronic HBV infection

Background: Research has shown that hepatitis B virus (HBV) genotypes are closely linked to the clinical manifestations, treatment, and prognosis of the disease. Objective: To study the association between genotype and drug-resistant HBV mutations in 620 Chinese patients with chronic HBV infection. Methods: HBV DNA levels were determined using real-time quantitative PCR in plasma samples. Microarrays were performed for the simultaneous detection of HBV genotypes (HBV/B, C, and D) and drug-resistance-related hotspot mutations. A portion of the samples analyzed using microarrays was selected randomly and the data were confirmed using direct DNA sequencing. Results: Most samples were genotype C (471/620; 76.0%), followed by genotype B (149/620; 24.0%). Among the 620 patient samples, 17 (2.7%) had nucleotide analogs (NA) resistance-related mutations. Of these, nine and eight patients carried lamivudine (LAM)-/telbivudine (LdT)-resistance mutations (rtL180M, rtM204I/V) and adefovir (ADV)-resistance mutations (rtA181T/V, rtN236T), respectively. No patients had both lamivudine (LAM)- and either ade-fovir (ADV) or entecavir (ETV) resistance mutations. Additionally, out of the 620 patient samples, 64.0% (397/620) were also detected with the precore stop-codon mutation (G1896A) by microarray assay. Conclusion: The results of the current study revealed that the prevalence of nucleotide analogs (NA)-resistance in Chinese hospitalized HBV-positive patients was so low that intensive nucleotide analogs (NA)-resistance testing before nucleotide analog (NA) treatment might not be required. In addition, the present study suggests that chronic HBV patients with genotype C were infected with fitter viruses and had an increased prevalence of nucleotide analogs (NA)-resistance mutations compared to genotype B virus. .

Comportamiento de la resistencia a drogas antirretrovirales en una consulta externa de La Habana durante el año 2012 / Resistance behavior to antiretroviral drugs in a havana outpatient consultation in 2012

INTRODUCCIÓN: la emergencia de virus de inmunodeficiencia humana tipo 1 (VIH-1) resistentes a antirretrovirales constituye una de las principales causas de fallo terapéutico. OBJETIVO: analizar las mutaciones asociadas a resistencia a los antirretrovirales y los niveles de resistencia en un grupo de pacientes con criterios de fallo a la terapia antirretroviral de gran actividad (TARGA) durante el año 2012.MÉTODOS: se colectaron muestras de plasma de 25 individuos con criterios de fallo a la TARGA, de los 157 pacientes positivos al VIH-1 que asistieron a la Consulta Externa de Infectología del Hospital "Hermanos Ameijeiras" durante el año 2012. Se determinó el subtipo viral y las mutaciones asociadas a resistencia y se estimó el tiempo transcurrido entre el inicio de la última terapia y la detección de virus resistente. RESULTADOS: 52 % de los pacientes solamente había recibido un régimen de TARGA. Se detectaron mutaciones asociadas a resistencia en 84 % de los pacientes. El 64 % presentó alta resistencia a los antirretrovirales empleados como primera estrategia terapéutica en el país. El tiempo promedio entre el inicio de la última terapia y la detección de virus resistente fue de 2,3 años. El 16 % de los pacientes presentó virus susceptibles, en este grupo la probabilidad de no adherencia a la TARGA pudo ser la causa del fallo terapéutico. CONCLUSIONES: se evidenciaron altos niveles de resistencia a la primera línea de TARGA empleada en Cuba y la aparición de variantes resistentes después de iniciar el tratamiento. Estos resultados enfatizan la necesidad del monitoreo de la resistencia como parte de la atención integral a las personas que viven con VIH/Sida.

INTRODUCTION: the emergence of resistant virus antiretroviral human immunodeficiency type 1 (HIV-1) is a major cause of treatment failure. OBJECTIVE: to analyze the mutations associated with antiretroviral resistance and resistance levels in a group of patients with failure criteria to antiretroviral therapy (HAART). METHODS: Plasma samples from 25 individuals with failure criteria to HAART were collected out of 157 HIV-1 positive patients attending the Outpatient Infectious Diseases at Hermanos Ameijeiras Hospital during 2012. The viral subtype and resistance mutations were determined; and the time between the beginning of the last therapy and detection of resistant viruses was estimated time. RESULTS: 52 % of patients had only received HAART regimen. Mutations associated with resistance in 84 % of patients were detected. 64 % had to antiretroviral treatment strategy employed as first high resistance in this country. The average time between the beginning of the last therapy and the detection of resistant viruses was 2.3 years. 16 % of patients had susceptible virus. The probability of non-adherence to HAART could be the cause of therapeutic failure in this group. CONCLUSIONS: high levels of resistance to first-line HAART used in Cuba and the emergence of resistant variants after starting treatment were evident. These results emphasize the need for monitoring resistance as part of comprehensive care for people living with HIV / AIDS.

Distribution of drug resistance mutations and genotypes in patients with chronic hepatitis B in Taicang city / 国际检验医学杂志

Objective To study the distribution of drug resistance mutations and genotypes in the patients with chronic hepatitis B(CHB)in Taicang area.Methods 350 cases of CHB were selected and detect the drug resistance mutations and genotypes before using nucleoside(acid)anti-viral drugs.The correlation between the drug resistance mutations with genotypes in CHB patients was analyzed.Results Among 350 cases of CHB,the distribution of genotypes was genotype B in 172 cases,accounting for 49.14%, genotype C in 164 cases,accounting for 46.85%,genotype D in 9 cases,accounting for 2.57%,mixed genotype of B and C in 5 ca-ses,accounting for 1.42%,no other genotypes were found.In this study,the drug resistance mutations were detected in 58 cases,in-cluding 22 cases of genotype B,35 cases of genotype C and 1 case of genotype D,no drug resistance mutations were found in mixed genotype B and C.The drug resistance mutations sites:lamivudine resistance-associated mutations in 36 cases(10.28%),and adefo-vir resistance-associated mutations in 16 cases(4.57%)and entecavir associated resistance mutations in 6 cases(1.71%).Conclusion The genotype of CHB patients in Taicang area was dominated by genotype B and C,which accounting for more than 90% and the proportion of these two kinds of genotype is similar.The proportion of drug resistance mutation occurrence in the patients with gen-otype C is higher than that with genotype B.The lamivudine resistance-associated mutation has the highest proportion of drug re-sistance occurrence.It is suggested that the CHB patients with undefined medication history and recurrence treatment should be per-formed the drug resistance detection for selecting the targeted therapeutic schemes before accepting nucleoside(acid)drug therapy.

New development of methods in HIV drug resistance study / 国际生物医学工程杂志

The emergence of drug resistance mutations in human immunodeficiency virus (HIV) genome is the major reason for antiviral treatments failure.To investigate the drug-resistance viral quasispecies in HIV-infected individuals and to find out the new drug resistance mutations have significant effects on directing effective clinical treatment and developing novel antiviral drugs.HIV drug resistance tests mainly include genotypic drug susceptibility assay and phenotypic drug susceptibility assay.We reviewed in this article some novel development in the field.

Screening program on novel drug resistance mutations of subtype B' in human immunodeficiency virus type 1 in China / 中华流行病学杂志

Objective To screen the level of novel drug resistance mutations in subtype B' in China. Methods 451 pol sequences collected from the previous study, which including 354 AIDS patients who had received antiretroviral treatment(ART)and 97 the untreated patients. Entire protease gene(codous 1-99)and full-length reverse transcriptase gene(codons 1-560)were included.Variation of mutations between the treated and the untreated patients with consensus/ancestral sequences were compared and the mutations with higher frequencies in the treated patients than in the untreated patients were screened before submitting the mutations to the Stanford HIV Drug Resistance Database(SHDB)(http://hivdb.stanford.edu/). Relation between the mutations and resistance preliminarily was then analyzed, according to the information including SHDB. Results Frequencies of 7 mutations at 6 positions, DI23E, V292I, K366R, T369A, T369V, A371V and 1375V, 2 at DNA polymerase domain and 5 at connection domain of reverse transcriptase(RT)were higher in the treated patients than in the untreated patients. The information of 7 mutations including the SHDB showed that 7 mutations were major variants at corresponding positions, and theirs frequencies were higher in the treated patients using some drugs, than in the untreated patients. Conclusion 7mutations being screened from the China subtype B were possibly associated with the resistance,which called for the construction of mutated viruses by site-directed mutagenesis to identify their effects on the susceptivity of different drugs.