Rapid detection of mutations associated with macrolide resistance in Mycobacterium avium complex.
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PROVIDER: S-EPMC163411 | BioStudies | 1996-01-01T00:00:00Z
REPOSITORIES: biostudies
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Project description:Clarithromycin (CLM) and azithromycin (AZM) are important agents in the treatment of disseminated Mycobacterium avium complex disease; however, monotherapy with these macrolides often leads to clinically significant resistance. The underlying resistance mechanism was investigated by comparing 23S rRNA gene sequences in the domain V region of 10 CLM-susceptible strains included in this study. The only differences in the domain V sequences associated with CLM resistance were at position 2274 of the complete M. avium 23S rRNA gene (GenBank accession no. X74494). All the CLM-susceptible strains had an A residue at this site, whereas seven of the eight CLM-resistant strains had either a C, G, or T. Four of these seven CLM-resistant strains emerged during monotherapy with CLM and two emerged during AZM monotherapy, showing that resistance selected by either macrolide was associated with mutation of the 23S rRNA gene. Thermodynamic analysis of secondary rRNA structure suggests that the observed mutations cause an alteration in free energy associated with rRNA folding, which may result in a localized conformation change in assembled ribosomes. Such a shift may be important in the resistance of ribosomes to the effects of macrolides. This study therefore establishes a link between mutations within the 23S rRNA gene and clinically significant macrolide resistance in M. avium and also identifies a possible molecular mechanism of resistance at the level of the ribosome.
| S-EPMC163001 | BioStudies
Project description:<h4>Background</h4>Macrolide is a key drug in the treatment of Mycobacterium avium complex pulmonary disease (MAC-PD). Macrolide-resistant MAC is gaining importance, but there are little data in clinical characteristics and treatment outcomes of macrolide-resistant MAC-PD (MR-MAC-PD).<h4>Methods</h4>We performed a systematic review and meta-analysis of published studies reporting clinical characteristics and treatment outcomes of patients with MR-MAC-PD. Risk of bias was assessed using the modified Newcastle-Ottawa Scale.<h4>Results</h4>Nine studies (seven retrospective and two prospective) comprising 319 patients were identified through a database search. Around 73% were women, and 52% had the fibrocavitary form. Pooled sputum culture conversion rate after combined multiple antibiotics or surgical resection was 21% (95% confidence interval [CI], 14-30%), and the one-year all-cause mortality was 10% (95% CI, 5-20%). There was no significant difference in treatment outcomes between nodular bronchiectatic and fibrocavitary types.<h4>Conclusions</h4>Even combination therapy with fluoroquinolone, aminoglycoside, and surgical resection, the treatment outcomes of MR-MAC-PD were poor. The investigation of new treatment modalities is urgent.
| S-EPMC6921583 | BioStudies
Project description:We verified the analytical performance characteristics of a previously described real-time reverse transcription-PCR (RT-PCR) assay targeting the open reading frame (ORF) 1b region of the severe acute respiratory syndrome coronavirus (SARS-CoV) with RNA transcripts. We then compared it to a novel nucleocapsid gene real-time RT-PCR assay with genomic RNA. The assays differed only in the primer and probe sequences and final concentrations. A commercially available armored RNA (Ambion, Austin, Tex.) was evaluated as positive control for the ORF 1b assay. The analytical sensitivity, reproducibility, amplification efficiency, and dynamic range of the assays were similar. Both were specific for SARS-CoV as determined by testing against human CoV 229E and OC43, specimens from patients without SARS, and by BLAST searches of GenBank for primer and probe sequence homology. The armored RNA was found to be a suitable positive control for the ORF 1b assay that could be reliably recovered and amplified from a variety of clinical specimens.
| S-EPMC356893 | BioStudies
Project description:Campylobacter, a major foodborne pathogen, is increasingly resistant to macrolide antibibotics. Previous findings suggeted that development of macrolide resistance in campylobacter requires a multi-step process, but the molecular mechanisms involved in the process are not known. In our study, multiple series of macrolide-resistant C. jejuni mutants were selected in vitro by stepwise exposure of C. jejuni NCTC11168 to increasing concentrations of erythromycin and tylosin. A set of the selected resistance were subjected to microarray and the the global transcriptional profile was analyzed. In this sery, DNA microarray was used to compare the gene expression profiles of macrolide resistant strains (68E1, 68E8 and 68E64) with its parent wild-type strain NCTC11168. The assay identified a small number of genes that showed significant changes (q-value<0.1) in expression in the low-level macrolide resistant strain 68E1, while a large number of gene showing significant changes in intermedia-level resistant stran 68E8 and high-level resistant strain 68 E64. The up-regulated genes in the resistant strains are involved in miscellaneous periplasmic proteins, efflux protienand putative aminotransferase, while the majority of the down-regulated genes are involved in electron transport,lipoprotein, heat shock protein and unknown function proteins. These findings suggest that there is not much change in low-level macrolide resistant C. jejuni strain. The over-expression of efflux pump and periplasmic protein was involved in the development of resistance to macrolide in C. jejuni. Keywords: macrolide resistant C. jejuni selected from NCTC 11168 step-wise selection. Overall design: The design utilized an available two color microarray slide for the entire transcriptome of Campylobacter jejuni. Four hybridizations were performed each with independently extracted samples of either macrolide susceptible C. jejuni NCTC11168 cDNA samples or macrolide resistant C.jejuni cDNA samples. A dye swap was utilized to help minimize dye dependent bias. Thus, there were four biological replicates of each sample.
2010-12-28 | GSE17881 | GEO
Project description:Campylobacter, a major foodborne pathogen, is increasingly resistant to macrolide antibibotics. previous findings suggeted that development of macrolide resistance in campylobacter requires a multi-step process, but the molecular mechanisms involved in the process are not known. In our study, multiple seriess of macrolide-resistant C. jejuni mutants were selected in vitro by stepwise exposure of C. jejuni 81-176 to increasing concentrations of erythromycin and tylosin. A set of the selected resistance were subjected to microarray and the the global transcriptional profile was analyzed. In this sery, DNA microarray was used to compare the gene expression profiles of macrolide resistant strains (76E2, 76E8 and 76E64) with its parent wild-type strain C. jejuni 81-176. This assay identified a large number of genes that showed >1.5 fold changes (q-value<0.1) in expression in the macrolide resistant strains. The up-regulated genes are involved in surface structure,ribosomal, heat shock and some specific Misc memerbrane , while the majority of the down-regulated genes are involved in energy metabolism, amino acid biosynthesis. The over-expression of genes involved in surface structure and Misc memerbrance was associated with the development of intermedial-level resistance to macrolide in campylobacter 81-176. Keywords:intermedial-level macrolide resistant C. jejuni selected from C. jejuni 81-176. step-wise selection. Overall design: The design utilized an available two color microarray slide for the entire transcriptome of Campylobacter jejuni. Four hybridizations were performed each with independently extracted samples of either macrolide susceptible C. jejuni 81-176 cDNA samples or macrolide resistant C. jejuni cDNA samples. A dye swap was utilized to help minimize dye dependent bias. Thus there were three to four biological replicates of each sample.
2010-12-28 | GSE17899 | GEO
Project description:We have found that early corticosteroid therapy was effective for reducing morbidity during five Korea-wide epidemics. We evaluated the clinical and laboratory parameters of 56 children who received early corticosteroid treatment for pneumonia that was caused by macrolide-resistant Mycoplasma pneumoniae (M. pneumoniae) or macrolide-sensitive M. pneumoniae between July 2019 and February 2020. All subjects had dual positive results from a PCR assay and serological test, and received corticosteroids within 24–36 h after admission. Point mutation of residues 2063, 2064, and 2067 was identified in domain V of 23S rRNA. The mean age was 6.8 years and the male:female ratio was 1.2:1 (31:25 patients). Most of the subjects had macrolide-resistant M. pneumoniae (73%), and all mutated strains had the A2063G transition. No significant differences in clinical and laboratory parameters were observed between macrolide-resistant and macrolide-sensitive M. pneumoniae groups that were treated with early dose-adjusted corticosteroids. Higher-dose steroid treatment may be needed for patients who have fever that persists for >48 h or increased biomarkers such as lactate dehydrogenase concentration at follow-up despite a usual dose of steroid therapy.
| S-EPMC8004593 | BioStudies
Project description:Campylobacter, a major foodborne pathogen, is increasingly resistant to macrolide antibibotics. previous findings suggeted that development of macrolide resistance in campylobacter requires a multi-step process, but the molecular mechanisms involved in the process are not known. In our study, multiple seriess of macrolide-resistant C. jejuni mutants were selected in vitro by stepwise exposure of C. jejuni 81-176 to increasing concentrations of erythromycin and tylosin. A set of the selected resistance were subjected to microarray and the the global transcriptional profile was analyzed. In this sery, DNA microarray was used to compare the gene expression profiles of macrolide resistant strains (76E2, 76E8 and 76E64) with its parent wild-type strain C. jejuni 81-176. This assay identified a large number of genes that showed >1.5 fold changes (q-value<0.1) in expression in the macrolide resistant strains. The up-regulated genes are involved in surface structure,ribosomal, heat shock and some specific Misc memerbrane , while the majority of the down-regulated genes are involved in energy metabolism, amino acid biosynthesis. The over-expression of genes involved in surface structure and Misc memerbrance was associated with the development of intermedial-level resistance to macrolide in campylobacter 81-176. Keywords:intermedial-level macrolide resistant C. jejuni selected from C. jejuni 81-176. step-wise selection. The design utilized an available two color microarray slide for the entire transcriptome of Campylobacter jejuni. Four hybridizations were performed each with independently extracted samples of either macrolide susceptible C. jejuni 81-176 cDNA samples or macrolide resistant C. jejuni cDNA samples. A dye swap was utilized to help minimize dye dependent bias. Thus there were three to four biological replicates of each sample.
2010-12-28 | E-GEOD-17899 | ArrayExpress
Project description:There was a high percentage of macrolide resistance in Mycoplasma pneumoniae clinical isolates in China. The genetic relatedness of macrolide-resistant M. pneunomiae strains was investigated using the multilocus variable-number tandem-repeat assay (MLVA). Among 152 M. pneunomiae isolates, the 137 macrolide-resistant strains were clustered into 15 MLVA types, indicating that the high macrolide resistance rate in M. pneumoniae is a result of the dissemination of the multiple resistant clones.
| S-EPMC3421490 | BioStudies
Project description:Campylobacter, a major foodborne pathogen, is increasingly resistant to macrolide antibibotics. Previous findings suggeted that development of macrolide resistance in campylobacter requires a multi-step process, but the molecular mechanisms involved in the process are not known. In our study, multiple series of macrolide-resistant C. jejuni mutants were selected in vitro by stepwise exposure of C. jejuni NCTC11168 to increasing concentrations of erythromycin and tylosin. A set of the selected resistance were subjected to microarray and the the global transcriptional profile was analyzed. In this sery, DNA microarray was used to compare the gene expression profiles of macrolide resistant strains (68E1, 68E8 and 68E64) with its parent wild-type strain NCTC11168. The assay identified a small number of genes that showed significant changes (q-value<0.1) in expression in the low-level macrolide resistant strain 68E1, while a large number of gene showing significant changes in intermedia-level resistant stran 68E8 and high-level resistant strain 68 E64. The up-regulated genes in the resistant strains are involved in miscellaneous periplasmic proteins, efflux protienand putative aminotransferase, while the majority of the down-regulated genes are involved in electron transport,lipoprotein, heat shock protein and unknown function proteins. These findings suggest that there is not much change in low-level macrolide resistant C. jejuni strain. The over-expression of efflux pump and periplasmic protein was involved in the development of resistance to macrolide in C. jejuni. Keywords: macrolide resistant C. jejuni selected from NCTC 11168 step-wise selection. The design utilized an available two color microarray slide for the entire transcriptome of Campylobacter jejuni. Four hybridizations were performed each with independently extracted samples of either macrolide susceptible C. jejuni NCTC11168 cDNA samples or macrolide resistant C.jejuni cDNA samples. A dye swap was utilized to help minimize dye dependent bias. Thus, there were four biological replicates of each sample.
2010-12-28 | E-GEOD-17881 | ArrayExpress
Project description:BACKGROUND:Mycobacterium avium complex prophylaxis is recommended for patients with advanced HIV infection. With the decrease in incidence of disseminated Mycobacterium avium complex infection and the availability of antiretroviral therapy (ART), the benefits of macrolide prophylaxis were investigated. This study examined the impact of macrolide prophylaxis on AIDS-defining conditions and HIV-associated mortality in a cohort of HIV-infected patients on ART. METHODS:Patients from TREAT Asia HIV Observational Database (September 2015 data transfer) aged 18 years and older with a CD4 count <50 cells/mm at ART initiation were included. The effect of macrolide prophylaxis on HIV-associated mortality or AIDS-defining conditions (as a combined outcome) and HIV-associated mortality alone were evaluated using competing risk regression. Sensitivity analysis was conducted in patients with a CD4 <100 cells/mm at ART initiation. RESULTS:Of 1345 eligible patients, 10.6% received macrolide prophylaxis. The rate of the combined outcome was 7.35 [95% confidence interval (CI): 6.04 to 8.95] per 100 patient-years, whereas the rate of HIV-associated mortality was 3.14 (95% CI: 2.35 to 4.19) per 100 patient-years. Macrolide use was associated with a significantly decreased risk of HIV-associated mortality (hazard ratio 0.10, 95% CI: 0.01 to 0.80, P = 0.031) but not with the combined outcome (hazard ratio 0.86, 95% CI: 0.32 to 2.229, P = 0.764). Sensitivity analyses showed consistent results among patients with a CD4 <100 cells/mm at ART initiation. CONCLUSIONS:Macrolide prophylaxis is associated with improved survival among Asian HIV-infected patients with low CD4 cell counts and on ART. This study suggests the increased usage and coverage of macrolide prophylaxis among people living with HIV in Asia.
| S-EPMC6391185 | BioStudies