Mutations In Resistance Genes Research Articles

Public health implications of antibiotic resistance in sewage water: an epidemiological perspective

The emergence and rapid spread of antibiotic resistance pose a major threat to global health, attributing to misuse and overuse of antibiotics resulting in antibiotics-resistant bacteria through natural mutation or transfer of resistance genes. A cross-sectional study was carried out, in which a total of 36 samples were systematically collected; of these, 26 were derived from the wastewater efflux and 10 from the receiving waters at several critical junctures along the Sutlej River. Herein, this study elucidated elevated levels of antibiotic resistance among bacterial isolates sourced from urban wastewater. Escherichia coli (E. coli) was the highest at 90% among the isolates, followed by Klebsiella pneumoniae (K. pneumoniae) at 58%, Pseudomonas aeruginosa (P. aeruginosa) at 55%, and Salmonella spp. at 53%. Many antibiotics were found to be more resistant including Ciproflaxacin, Co-Trimaxazole, Ampicillin and Tetracycline. Several antibiotic-resistance genes were found in isolated bacterial spp., such as Aminoglycosides (aadA), Sulfonamides (Sul1, Sul3), Tetracyclines (Tet (A/B/D)) and Cephalosporins (Bla_CTM X) at 41%, 35%, 29% and 12% respectively. Furthermore, the development of innovative wastewater treatment models and surveillance programs are crucial to counteract the dissemination of antibiotic resistance. To investigate the genetic determinants of antibiotic resistance, molecular analysis was performed, including DNA isolation, PCR amplification, and sequence analysis. The study helps investigate a diverse range of ARBs and ARGs in wastewater, which highlights the need of better laws for antibiotic usage and wastewater treatment processes. This investigation also stresses on regular monitoring of ARBs and ARGs in sewage wastewater. Through proactive interventions and sustained scientific inquiry, we can strive toward preserving environmental integrity and public health for successive generations.Graphical

Analysis of virus gene subtypes and drug resistance monitoring results of newly reported HIV/AIDS population in Anhui Province from 2020 to 2023

Objective: To investigate the genetic subtypes and drug resistance monitoring of newly reported human immunodeficiency virus (HIV) infection/AIDS virus in Anhui Province from 2020 to 2023. Methods: An observational design study was used to collect blood samples from patients diagnosed with HIV/AIDS in the AIDS Prevention and Control Department of Anhui Provincial Center for Disease Control and Prevention from January 2020 to December 2023.The HIV-1 pol gene was amplified by reverse transcription-nested PCR, and the genetic subtypes were identified by phylogenetic tree analysis using MEGA 7.0 software. The mutation sites of drug resistance were analyzed by the online software tool of Stanford University's HIV Drug resistance database. The influencing factors of drug resistance before treatment were analyzed by multivariate logistic analysis. Results: A total of 335 plasma samples were collected, and 332 HIV-1 pol gene sequences were obtained successfully. The main gene subtypes were CRF01-AE, accounting for 35.55% (118/332), followed by CRF07-BC, B and B+C types [29.22% (97/332), 11.74% (39/332), 9.93% (33/332)]. The total drug resistance rate before treatment was 30.12%(32/100), and the drug resistance rate of protease inhibitor (PIs) in HIV-1 was 6.33% (21/332). The drug resistance rate of nucleoside reverse transcriptase inhibitors (NRTI) before treatment was 6.33% (21/332). The drug resistance rate of non-nucleoside reverse transcriptase inhibitors (NNRTI) before treatment was 17.47% (58/332).The comparison of drug resistance rate of different drug types showed statistical significance (χ2=30.435, P<0.05).Among the 100 cases of drug resistance, the main mutation point of HIV-1 protease inhibitor was Q58E (21.00%), and the main mutation point of nucleoside reverse transcriptase inhibitor was M184V/I (6.00%). Non-nucleoside reverse transcriptase inhibitor resistance mutation points mainly K103N (22.00%).There were statistically significant differences in the starting time of antiviral therapy, the number of CD4+T cells at baseline and the drug resistance rate of gene subtypes (the chi-square values are respectively 24.152, 32.516, 11.652, P<0.05).Multivariate logistic analysis showed that the baseline CD4+T cell count was <200/μl, subtype B, subtype B+C, CRF01-AE subtype, CRF55-01B subtype and 01-BC subtype was the influential factor of drug resistance before treatment (the chi-square values are respectively 4.577, 8.202, 4.416, 5.206, 7.603 and 4.804, P<0.05). Conclusion: The newly reported HIV/AIDS population in Anhui Province from 2020 to 2023 has a variety of viral gene subtypes, and NNRTIs are the main types of drug resistance gene mutations before treatment. Attention should be paid to the number of baseline CD4+T cells, the duration of antiviral treatment, and the distribution of gene subtypes to reduce the drug resistance of HIV/AIDS patients before treatment.

Point Mutations in Furazolidone and Rifampicin Resistance Genes in Helicobacter pylori Strains from Colombia.

The eradication of Helicobacter pylori is a valid strategy for preventing gastric cancer; however, the therapeutic failure of first-line treatments in Colombia is associated with high resistance to metronidazole and amoxicillin. This study explored alternative antibiotics and analyzed point mutations in resistance genes to furazolidone and rifampicin in order to include them in rescue therapy regimens. A total of 239 complete genomes of Helicobacter pylori Colombian strains were compared to that of the ATCC 26695 strain to identify mutations in the rpoB and porD genes for rifampicin and furazolidinone resistance, respectively. While rifampicin resistance mutations were not found, only 0.84% of the isolates showed the porD gene, suggesting that Helicobacter pylori is sensitive to these antibiotics. A phylogenomic analysis of Helicobacter pylori revealed an independent lineage in Colombia (hspColombia). The absence of point mutations in the rpoB gene, together with the scarce mutations identified in the porD gene of Helicobacter pylori, suggest that the hspColombia isolates are sensitive to rifampicin and furazolidone, which could be key to including these antibiotics in the rescue therapies against Helicobacter pylori.

Antibiotic resistance alters the ability of Pseudomonas aeruginosa to invade bacteria from the respiratory microbiome.

The emergence and spread of antibiotic resistance in bacterial pathogens is a global health threat. One important unanswered question is how antibiotic resistance influences the ability of a pathogen to invade the host-associated microbiome. Here we investigate how antibiotic resistance impacts the ability of a bacterial pathogen to invade bacteria from the microbiome, using the opportunistic bacterial pathogen Pseudomonas aeruginosa and the respiratory microbiome as our model system. We measure the ability of P. aeruginosa spontaneous antibiotic-resistant mutants to invade pre-established cultures of commensal respiratory microbes in an assay that allows us to link specific resistance mutations with changes in invasion ability. While commensal respiratory microbes tend to provide some degree of resistance to P. aeruginosa invasion, antibiotic resistance is a double-edged sword that can either help or hinder the ability of P. aeruginosa to invade. The directionality of this help or hindrance depends on both P. aeruginosa genotype and respiratory microbe identity. Specific resistance mutations in genes involved in multidrug efflux pump regulation are shown to facilitate the invasion of P. aeruginosa into Staphylococcus lugdunensis, yet impair invasion into Rothia mucilaginosa and Staphylococcus epidermidis. Streptococcus species provide the strongest resistance to P. aeruginosa invasion, and this is maintained regardless of antibiotic resistance genotype. Our study demonstrates how the cost of mutations that provide enhanced antibiotic resistance in P. aeruginosa can crucially depend on community context. We suggest that attempts to manipulate the microbiome should focus on promoting the growth of commensals that can increase the fitness costs associated with antibiotic resistance and provide robust inhibition of both wildtype and antibiotic-resistant pathogen strains.

Multidrug resistance 1 (MDR1) gene mutation in dogs

The multidrug resistance (MDR1) gene mutation in the domestic dog (Canis lupus familiaris) is an inherited condition most frequently observed in herding breeds. Dogs with the mutated gene are at risk of neurological toxicosis and life-threatening reactions if certain drugs are administered. Determining the MDR1 genotype of a dog via blood or buccal swab sampling will assist owners and veterinary professionals in understanding their risk of multidrug sensitivity. Some of the drugs known to be dangerous when administered to a dog with the mutation are used in everyday practice. To ensure patient safety, the student and registered veterinary nurse should have an understanding of this condition, particularly when dealing with the dog breeds at higher risk. This article aims to provide student and registered veterinary nurses with a comprehensive and logical analysis of the MDR1 gene mutation in dogs.

Pattern of Mutations in Rifampicin Resistance (rpoB) Gene and Analysis of Rifampicin Indeterminate Result in Tuberculosis Detected by Xpert MTB/RIF Assay in Kalaburagi, India

Tuberculosis (TB) is a serious disease that has been observed since ancient times. In the mid-to late-20th century, the main clinical approach to this disease involved focusing on its diagnosis, prevention, and treatment. However, in the 21st century, the focus has shifted toward the diagnosis and treatment of drug-resistant TB. With the use of the Xpert MTB/RIF assay at the frontlines in India, interpreting indeterminate results to treatment with rifampicin, an antitubercular drug, can be challenging. This is further exacerbated by a lack of knowledge regarding mutation frequency in antitubercular drug-resistant genes in this region. Among antitubercular drugs, rifampicin is the most potent and effective drug for the treatment of tuberculosis; hence, understanding the pattern of rifampicin resistance (rpoB) gene mutations will provide insights into the genetic basis of this resistance, which may help in the prevention and treatment of TB. This retrospective observational study presents sociodemographic details, sample types, Mycobacterium tuberculosis load, types of probe mutations detected, and rifampicin indeterminate results from the Xpert MTB/RIF assay. Of the 314 samples analyzed, 258 showed rifampicin resistance as detected by MTB, with 56 samples of MTB-detected rifampicin indeterminate results. Type E probe mutation (58.9%) was the most common type, while the least frequent mutation was Type C probe (1.5%). No missing probe was observed in approximately 8.9% of samples. Among the 56 rifampicin indeterminate results, the maximum Cycle threshold value did not cross 34.5 in six samples.

Phenotypic and Genotypic Characterization of Candida parapsilosis complex isolates from a Lebanese Hospital.

The opportunistic fungal pathogen Candida parapsilosis is a major causative agent of candidiasis leading to death in immunocompromised individuals. Azoles are the first line of defense in treatment by inhibiting ERG11, involved in the synthesis of ergosterol, the main sterol fungal sterol. Resistance to azoles is on the increase worldwide including in Lebanon. The purpose of this study is to characterize nine hospital isolates labeled as C. parapsilosis: four resistant and five sensitive to fluconazole. Phenotypic characterization was achieved through a battery of tests that target pathogenicity attributes such as virulence, biofilm formation, stress resistance, and ergosterol content. Genotypic analysis was done through whole genome sequencing to mutations in key virulence and resistance genes. Phylogenetic comparison was performed to determine strain relatedness and clonality. Genomic data and phylogenetic analysis revealed that three of the nine C. parapsilosis isolates were misidentified; two as C. orthopsilosis and C. metapsilosis belonging to the C. parapsilosis complex, while the third was C. albicans. Moreover, several known and novel mutations in key drug resistance and virulence genes were identified such as ERG11, ERG3, ERG6, CDR1, and FAS2. Phylogenetic analysis revealed a high degree of relatedness and clonality within our C. parapsilosis isolates. Our results showed that resistant isolates had no increased ergosterol content, no statistically significant difference in virulence, but exhibited an increase in biofilm content compared to the sensitive isolates. In conclusion, our study, the first of its kind in Lebanon, suggests several mechanisms of antifungal drug resistance in C. parapsilosis hospital isolates.

Chest Computed Tomography Radiomics for Determining Macrolide Resistance-Associated Gene Mutation Status in Children with Mycoplasma pneumoniae Pneumonia: A Two-Center Study

Rationale and ObjectivesThe mutations in the 23S ribosomal RNA (rRNA) gene are associated with an increase in resistance to macrolides in children with Mycoplasma pneumoniae pneumonia (MPP). This study aimed to develop and validate a chest computed tomography (CT) radiomics model for determining macrolide resistance-associated gene mutation status in MPP. Materials and MethodsA total of 258 MPP patients were retrospectively included from two institutions (training set: 194 patients from the first institution; external test set: 64 patients from the second). The 23S rRNA gene mutation status was tested by nasopharyngeal swab polymerase chain reaction. Radiomics features were extracted from chest CT images of pulmonary lesions segmented with semi-automatic delineation. Subsequently, radiomics feature reduction was applied to identify the most relevant features. Logistic regression and random forest algorithms were employed to establish the radiomics models, which were five-fold cross-validated in the training set and validated in the external test set. ResultsThe radiomics feature selection resulted in eight features. After five-fold cross-validation in the training set, the mean areas under the receiver operating characteristic curve (AUCs) of the logistic regression and random forest models were 0.868 (95% confidence interval (CI): 0.813-0.923) and 0.941 (95% CI: 0.907-0.975), respectively. In the external test set, the corresponding AUCs were 0.855 (95% CI: 0.758-0.952) and 0.815 (95% CI: 0.705-0.925). ConclusionChest CT radiomics is a promising diagnostic tool for determining macrolide resistance gene mutation status in MPP. Availability of data and materialThe datasets generated or analyzed during the study are available from the corresponding author on reasonable request.

Development of a rapid detection method for the macrolide resistance gene in Mycobacterium avium using the amplification refractory mutation system-loop-mediated isothermal amplification method.

Macrolide antibiotics such as clarithromycin (CLR) and azithromycin are the key drugs used in multidrug therapy for Mycobacterium avium complex (MAC) diseases. For these antibacterial drugs, drug susceptibility has been correlated with clinical response in MAC diseases. We have previously demonstrated the correlation between drug susceptibility and mutations in the 23S rRNA gene, which confers resistance to macrolides. Herein, we developed a rapid detection method using the amplification refractory mutation system (ARMS)-loop-mediated isothermal amplification (LAMP) technique to identify mutations in the 23S rRNA gene of M. avium. We examined the applicability of the ARMS-LAMP method to genomic DNA extracted from six genotypes of M. avium clinical isolates. The M. avium isolates were classified into 21 CLR-resistant and 9 CLR-susceptible strains based on the results of drug susceptibility tests; the 23S rRNA genes of these strains were sequenced and analyzed using the ARMS-LAMP method. Sequence analysis revealed that the 9 CLR-sensitive strains were wild-type strains, whereas the 21 CLR-resistant strains comprised 20 mutant-type strains and one wild-type strain. Using ARMS-LAMP, no amplification from genomic DNAs of the 10 wild-type strains was observed using the mutant-type mismatch primer sets (MTPSs); however, amplification from the 20 mutant-type strain DNAs was observed using the MTPSs. The rapid detection method developed by us integrates ARMS-LAMP with a real-time turbidimeter, which can help determine drug resistance in a few hours. In conclusion, ARMS-LAMP might be a new clinically beneficial technology for rapid detection of mutations.IMPORTANCEMultidrug therapy for pulmonary Mycobacterium avium complex disease is centered on the macrolide antibiotics clarithromycin and azithromycin, and resistance to macrolides is an important prognosticator for clinical aggravation. Therefore, it is important to develop a quick and easy method for detecting resistance to macrolides. Drug resistance is known to be correlated with mutations in macrolide resistance genes. We developed a rapid detection method using amplification refractory mutation system (ARMS)-loop-mediated isothermal amplification (LAMP) to identify a mutation in the 23S rRNA gene, which is a macrolide resistance gene. Furthermore, we examined the applicability of this method using M. avium clinical isolates. The rapid method developed by us for detection of the macrolide resistance gene by integrating ARMS-LAMP and a real-time turbidimeter can help in detection of drug resistance within a few hours. Since this method does not require expensive equipment or special techniques and shows high analytical speed, it would be very useful in clinical practice.

Identification of knowledge gaps in whole-genome sequence analysis of multi-resistant thermotolerant Campylobacter spp.

BackgroundCampylobacter spp. is the most frequent cause of bacterial food-borne gastroenteritis and a high priority antibiotic resistant bacterium according to the World Health Organization (WHO). European monitoring of thermotolerant Campylobacter spp. does not reflect the global burden of resistances already circulating within the bacterial population worldwide.MethodsWe systematically compared whole genome sequencing with comprehensive phenotypic antimicrobial susceptibility, analyzing 494 thermotolerant Campylobacter poultry isolates from Vietnam and Germany. Any discrepancy was checked by repeating the wet lab and improving the dry lab part. Selected isolates were additionally analyzed via long-read Oxford Nanopore technology, leading to closed chromosomes and plasmids.ResultsOverall, 22 different resistance genes and gene variants (e. g. erm(B), aph(3’)-IIIa, aph(2’’)-If, catA, lnu(C), blaOXA, sat4) and point mutations in three distinct genes (gyrA, 23S rRNA, rpsL) associated with AMR were present in the Campylobacter isolates. Two AMR genes were missing in the database and one falsely associated with resistance. Bioinformatic analysis based on short-read data partly failed to identify tet(O) and aadE, when the genes were present as duplicate or homologous gene variants. Intriguingly, isolates also contained different determinants, redundantly conferring resistance to chloramphenicol, gentamicin, kanamycin, lincomycin and streptomycin. We found a novel tet(W) in tetracycline sensitive strains, harboring point mutations. Furthermore, analysis based on assemblies from short-read data was impaired to identify full length phase variable aad9, due to variations of the poly-C tract within the gene. The genetic determinant responsible for gentamicin resistance of one isolate from Germany could not be identified. GyrT86I, presenting the main determinant for (fluoro-)quinolone resistance led to a rare atypical phenotype of ciprofloxacin resistance but nalidixic acid sensitivity. Long-read sequencing predicted AMR genes were mainly located on the chromosome, and rarely on plasmids. Predictions from long- and short-read sequencing, respectively, often differed. AMR genes were often organized in multidrug resistance islands (MDRI) and partially located in proximity to transposase genes, suggesting main mobilization of resistance determinants is via natural transformation and transposition in Campylobacter.ConclusionsThe results of this study suggest that there is frequent resistance gene duplication, mosaicism, and mutation leading to gene variation and truncation in Campylobacter strains that have not been reported in previous studies and are missing from databases. Furthermore, there is a need for deciphering yet unknown resistance mechanisms and resistance spread in thermotolerant Campylobacter spp. that may pose a challenge to global food safety.

Mutational Dynamics Related to Antibiotic Resistance in M. tuberculosis Isolates from Serial Samples of Patients with Tuberculosis and Type 2 Diabetes Mellitus.

Genetic variation in tuberculosis is influenced by the host environment, patients with comorbidity, and tuberculosis-type 2 diabetes mellitus (TB-T2DM) and implies a higher risk of treatment failure and development of drug resistance. Considering the above, this study aimed to evaluate the influence of T2DM on the dynamic of polymorphisms related to antibiotic resistance in TB. Fifty individuals with TB-T2DM and TB were initially characterized, and serial isolates of 29 of these individuals were recovered on day 0 (diagnosis), 30, and 60. Genomes were sequenced, variants related to phylogeny and drug resistance analyzed, and mutation rates calculated and compared between groups. Lineage X was predominant. At day 0 (collection), almost all isolates from the TB group were sensitive, apart from four isolates from the TB-T2DM group showing the mutation katG S315T, from which one isolate had the mutations rpoB S450L, gyrA A90G, and gyrA D94G. This pattern was observed in a second isolate at day 30. The results provide a first overview of the dynamics of mutations in resistance genes from individuals with TB-T2DM, describing an early development of resistance to isoniazid and a rapid evolution of resistance to other drugs. Although preliminary, these results help to explain the increased risk of drug resistance in individuals with TB and T2DM.

Molecular Analysis of Pseudomonas aeruginosa Isolates with Mutant gyrA Gene and Development of a New Ciprofloxacin Derivative for Antimicrobial Therapy.

This study focuses on the prevalence of Pseudomonas aeruginosa in various medical specimens. In addition, the investigates of this research shows the genetic analysis of pathogen-resistant isolates and chemical modifications to ciprofloxacin. A total of 225 specimens from men and women aged 30 to 60 were carefully collected and examined, including samples from wound, burn, urine, sputum, and ear samples. The data were obtained from AL Muthanna hospitals. PCR-RFLP and gene expression analysis were used to identify resistant strains and explore the genetic basis of antibiotic resistance. A ciprofloxacin derivative was synthesized and confirmed through FT-IR, 1H-NMR, and mass spectroscopy techniques then it was tested as antibacterial agent. Also, molecular docking study was conducted to predict the mechanism of action for the synthesized derivative. The results demonstrated that wound samples had the highest positive rate (33.7%) of P. aeruginosa isolates. The PCR-RFLP testing correlated ciprofloxacin resistance with gyrA gene mutation. Gene expression analysis revealed significant changes in the gyrA gene expression in comparison to the reference rpsL gene subsequent to exposure to the synthesized derivative. Furthermore, the molecular docking investigation illustrated the strategic positioning of the ciprofloxacin derivative within the DNA-binding site of the gyrA enzyme. The examination of genetic expression patterns manifested diverse effects attributed to the CIP derivative on P. aeruginosa, thus portraying it as a viable candidate in the quest for the development of novel antimicrobial agents. Ciprofloxacin derivative may offer new antimicrobial therapeutic options for treating Pseudomonas aeruginosa infections in wound specimens, addressing resistance and gyrA gene mutations.

Optimization of an allelic discrimination real-time RT-PCR assay for detection of H275Y oseltamivir resistance gene mutation among influenza A(H1N1)pdm09 patients from 2020 to 2022.

Influenza virus is known to cause mild to severe respiratory infections and is also prone to genetic mutations. Of all the mutations, neuraminidase (NA) gene mutations are a matter of concern, as most approved antivirals target this protein. During the 2020 influenza season, an emergence of mutation in the NA gene, affecting the binding of the World Health Organization (WHO)-recommended probes to the specific site of the NA gene, was reported by our group. As a result of this mutation, the WHO-recommended allelic discrimination real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay was unable to detect wild-type (H275) or mutant oseltamivir-resistant (Y275) strains of influenza A(H1N1)pmd09 viruses. In the current study, the WHO-recommended probes were redesigned according to the mutation in the probe binding site. Fifty undetermined samples (2020-2021) from the previous study were retested with the newly designed probes and found to be positive for H275 and/or Y275. The results obtained were similar to the Sanger sequencing results from the previous study, suggesting that the redesigned probes were efficient in discriminating between wild-type and mutant-type viruses. Furthermore, 133 samples from 2022, making a total of 183 samples (2020-2022), were tested using improved allelic discrimination real-time RT-PCR, and the overall prevalence rate of oseltamivir resistance in 2020-2022 was found to be 0.54%.

Linezolid Resistance Genes and Mutations among Linezolid-Susceptible Enterococcus spp.-A Loose Cannon?

The National Reference Centre for Enterococci receives an increasing number of linezolid-resistant Enterococcus isolates. Linezolid (LIN) resistance is mediated by G2576T 23S rDNA gene mutations and/or acquisition of resistance genes (cfr, optrA, poxtA). There are anecdotal reports that those resistance traits may be present in phenotypically linezolid-susceptible isolates. We aimed to determine the prevalence of LIN resistance genes and mutations in enterococci with a LIN MIC of 4 mg/L in broth microdilution (EUCAST = susceptible) isolated from German hospital patients 2019-2021. LIN MICs were additionally determined by ETEST® and VITEK2. Selected strains were subjected to LIN selective pressure and growth was monitored with increasing antibiotic concentrations. We received 195 isolates (LIN MIC = 4 mg/L). In total, 78/195 (40%) isolates contained either a putative resistance gene, the G2576T mutation, or a combination thereof. Very major error was high for broth microdilution. The ability to predict phenotypic resistance from genotypic profile was highest for G2576T-mediated resistance. Selection experiments revealed that, in particular, E. faecium isolates with resistance gene mutations or poxtA rapidly adapt to MICs above the clinical breakpoint. In conclusion, LIN resistance genes and mutations can be observed in phenotypically linezolid-susceptible enterococci. Those isolates may rapidly develop resistance under LIN selective pressure potentially leading to treatment failure.

The Antibiotic Resistance Crisis

Numerous deaths from infectious diseases have raised public awareness of their dangers, promoting global antimicrobial research. However, antibiotic demand and use, on the other hand, have increased antibiotic levels in natural ecosystems. Natural selection and adaptation induced antibiotic resistance gene mutations in bacterial populations. Dissemination of antibiotic resistance genes in ecosystems resulted in the emergence of antibiotic-resistant bacteria, leading to a variety of antibiotic-resistant diseases on a global scale. This review paper provides an overview of the antibiotic discovery history, antibiotic screening techniques, and industrial antibiotic production processes. In addition, the emergence of antibiotic-resistant microorganisms and the antibiotics’ impact on the environment have been reviewed, and suggestions were given. The ecological perspective on antibiotic resistance has also been discussed. New drug development seems to be the prime requisite now to control microbes that no longer respond to the drug.&#x0D;

Correlation analysis of endoscopic manifestations and eradication effect of Helicobacter pylori.

Helicobacter pylori (H. pylori) infection is the most important risk factor for gastric cancer. Eradication of H. pylori significantly reduces the incidence and mortality of gastric cancer. H. pylori resistance to antibiotics and a gradual decline in eradication rates are gaining more and more attention. Our study aimed to address the correlation between endoscopic manifestations and the eradication effect of H. pylori. We retrospectively reviewed outpatients in our hospital with H. pylori infection undergoing eradication therapy from January 2022 to March 2023. Both the primary diagnosis and eradication of H. pylori after treatment were confirmed by a 13C urea breath test. Patients were treated with a proton pump inhibitor (PPI)-based quadruple therapy. Clinical characteristics and endoscopy manifestations within 7 days before or after patients were diagnosed with H. pylori infection were analyzed. From January 2022 to March 2023, a total of 323 patients were enrolled in this study. There were 138 male patients and 185 female patients. The mean age of patients was 45.62 ± 13.04 years. The H. pylori initial eradication rate was 82.0%. Univariate analysis of factors affecting H. pylori eradication showed that sex, age, and endoscopic manifestations including diffuse redness, multiple white, and flat elevated lesions, and atrophy were significantly associated with the failure of H. pylori eradication therapy. A multivariable logistic regression model analysis of these five factors showed that patients aged over 60 years with multiple white and flat elevated lesions in the endoscopic examination are significantly less likely to eradicate H. pylori with empirical quadruple therapy. On the other hand, patients with diffuse redness were significantly more likely to eradicate H. pylori infection with empirical quadruple therapy. Our study shows that age over 60 years old, multiple white and flat elevated lesions in endoscopic examination are independent risk factors of initial H. pylori eradication failure with empirical quadruple therapy, while diffuse redness in endoscopic examination is a protective factor of initial H. pylori eradication failure with empirical quadruple therapy, while diffuse redness in endoscopic examination is a protective factor. For patients with these risk factors, a drug sensitivity test or H. pylori resistance gene mutation detection may be more appropriate. However, further mechanism studies or prospective studies are needed to prove our findings.

A high proportion of caseous necrosis, abscess, and granulation tissue formation in spinal tuberculosis.

The special blood circulation, anatomy, and tissue structure of the spine may lead to significant differences in pathological features and drug resistance between spinal tuberculosis and pulmonary tuberculosis. Here, we collected 168 spinal tuberculosis cases and 207 pulmonary tuberculosis cases, and compared their clinical and pathological features as well as drug resistance. From the anatomical location, the highest incidence was of lumbar tuberculosis, followed by thoracic tuberculosis. PET-CT scans showed increased FDG uptake in the diseased vertebrae, discernible peripheral soft tissue shadow, visible internal capsular shadow, and an abnormal increase in FDG uptake. MRI showed infectious lesions in the diseased vertebral body, formation of paravertebral and bilateral psoas muscle abscess, and edema of surrounding soft tissues. As with control tuberculosis, the typical pathological features of spinal tuberculosis were chronic granulomatous inflammation with caseous necrosis. The incidence of granulomas was not statistically different between the groups. However, the proportions of caseous necrosis, acute inflammation, abscess, exudation, and granulation tissue formation in the spinal tuberculosis group were all significantly increased relative to the control tuberculosis group. Compared to the control tuberculosis group, the incidences of resistance to rifampicin (RFP) + isoniazid (INH) + streptomycin (STR) and INH + ethambutol (EMB) were lower in the spinal tuberculosis group, while the incidences of resistance to RFP + INH + EMB and RFP + EMB were higher. Moreover, we also found some differences in drug-resistance gene mutations. In conclusion, there are noticeable differences between spinal Mycobacterium tuberculosis and pulmonary tuberculosis in pathological characteristics, drug resistance, and drug resistance gene mutations.

Using Microfluidic Chip and Allele-Specific PCR to Rapidly Identify Drug Resistance-Associated Mutations of Mycobacterium tuberculosis.

The currently used conventional susceptibility testing for drug-resistant Mycobacterium tuberculosis (M.TB) is limited due to being time-consuming and having low efficiency. Herein, we propose the use of a microfluidic-based method to rapidly detect drug-resistant gene mutations using Kompetitive Allele-Specific PCR (KASP). A total of 300 clinical samples were collected, and DNA extraction was performed using the "isoChip®" Mycobacterium detection kit. Phenotypic susceptibility testing and Sanger sequencing were performed to sequence the PCR products. Allele-specific primers targeting 37 gene mutation sites were designed, and a microfluidic chip (KASP) was constructed using 112 reaction chambers to simultaneously detect multiple mutations. Chip validation was performed using clinical samples. Phenotypic susceptibility of clinical isolates revealed 38 rifampicin (RIF)-resistant, 64 isoniazid (INH)-resistant, 48 streptomycin (SM)-resistant and 23 ethambutol (EMB)-resistant strains, as well as 33 multi-drug-resistant TB (MDR-TB) strains and 20 strains fully resistant to all four drugs. Optimization of the chip-based detection system for drug resistance detection showed satisfactory specificity and maximum fluorescence at a DNA concentration of 1×101 copies/µL. Further analysis revealed that 76.32% of the RIF-resistant strains harbored rpoB gene mutations (sensitivity, 76.32%; specificity 100%), 60.93% of the INH-resistant strains had katG gene mutations (sensitivity, 60.93%; specificity, 100%), 66.66% of the SM-resistant strains carried drug resistance gene mutations (sensitivity, 66.66%; specificity, 99.2%), and 69.56% of the EMB-resistant strains had embB gene mutations (sensitivity, 69.56%; specificity, 100%). Further, the overall agreement between the microfluidic chip and Sanger sequencing was satisfactory, with a turnaround time of the microfluidic chip was approximately 2 hours, much shorter than the conventional DST method. The proposed microfluidic-based KASP assay provides a cost-effective and convenient method for detecting mutations associated with drug resistance in M. tuberculosis. It represents a promising alternative to the traditional DST method, with satisfactory sensitivity and specificity and a much shorter turnaround time.

Site-directed mutagenesis of Mycobacterium tuberculosis and functional validation to investigate potential bedaquiline resistance-causing mutations

Molecular detection of bedaquiline resistant tuberculosis is challenging as only a small proportion of mutations in candidate bedaquiline resistance genes have been statistically associated with phenotypic resistance. We introduced two mutations, atpE Ile66Val and Rv0678 Thr33Ala, in the Mycobacterium tuberculosis H37Rv reference strain using homologous recombineering or recombination to investigate the phenotypic effect of these mutations. The genotype of the resulting strains was confirmed by Sanger- and whole genome sequencing, and bedaquiline susceptibility was assessed by minimal inhibitory concentration (MIC) assays. The impact of the mutations on protein stability and interactions was predicted using mutation Cutoff Scanning Matrix (mCSM) tools. The atpE Ile66Val mutation did not elevate the MIC above the critical concentration (MIC 0.25–0.5 µg/ml), while the MIC of the Rv0678 Thr33Ala mutant strains (> 1.0 µg/ml) classifies the strain as resistant, confirming clinical findings. In silico analyses confirmed that the atpE Ile66Val mutation minimally disrupts the bedaquiline-ATP synthase interaction, while the Rv0678 Thr33Ala mutation substantially affects the DNA binding affinity of the MmpR transcriptional repressor. Based on a combination of wet-lab and computational methods, our results suggest that the Rv0678 Thr33Ala mutation confers resistance to BDQ, while the atpE Ile66Val mutation does not, but definite proof can only be provided by complementation studies given the presence of secondary mutations.

Analysis of characteristics of drug resistance gene mutation in HBV RT region of hepatitis B infected patients

Objective: This article investigated the clinical characteristics and distribution of drug resistance mutation sites in HBV RT region of hepatitis B infected patients. Methods: Retrospective analysis was made on 1 948 patients with HBV infection, who had been tested for NAs resistance mutation and had a medical history of NAs in the Laboratory Department of the Fifth Medical Center of the PLA General Hospital from January 2020 to December 2021. Basic clinical information and drug resistance related mutation information were recorded. Meanwhile, the serological index data of hepatitis B were collected. Drug resistance gene mutant group and non-mutated group were grouped according to whether the drug resistance genes had a mutation in HBV RT region, and the clinical characteristics and genotype distribution of the two groups were statistically analyzed. The pattern of drug resistance gene mutation, number of mutation sites, drug resistance type and mutation of NAs resistance-related sites were analyzed in 917 patients with drug resistance gene mutation in HBV RT region. χ2 Inspection was used for counting data. Meanwhile, two independent samples t-test and Wilcoxon rank sum test were used for measurement data. Results: Among the 1 948 patients with chronic HBV infection, 917 patients had drug resistance gene mutation in RT region (47.07%). The proportion of patients with acute hepatitis B and CHB in HBV RT resistance gene mutant group was lower than that in the non-mutated group, while the proportion of patients with HBV-related cirrhosis was higher than that in the non-mutated group, these differences were statistically significant. Compared with the non-mutated group in HBV RT region, the age, the positive rates of HBeAg and HBV DNA, and HBV DNA load of these patients were increased in drug resistance gene mutant group, these differences were statistically significant. Genotypes of patients in both groups were dominated by C, followed by B and D. The proportion of patients with genotype C in HBV RT drug resistance gene mutant group was higher than that of non-mutated group, the difference was statistically significant. There were 53 gene mutation patterns in 917 patients with drug resistance gene mutation in HBV RT region, and the main pattern was rtL180M+rtM204V+rtS202G (9.70%). The mutation sites were dominated by 3 (20.74%). There were 5 types of drug resistance, LAM+Ldt (21.25%) was the most. Among the 18 sites that were clearly associated with LAM, ADV, ETV and Ldt resistance in the HBV RT region, 14 sites were mutated, and the most common mutation sites were rtL180M, rtM204V, rtM204 and rtS202G. what's more, the proportion of patients with NAs drug resistance was LAM>Ldt>ETV>ADV. Conclusion: In order to prevent adverse consequences of this study such as disease recurrence or disease progression caused by HBV drug resistance, HBV infected patients, who have long-term use of NAs antiviral therapy, should monitor the level of HBV DNA and drug resistance genes in HBV RT region in order to optimize the treatment plan in time or guide individualized treatment.