Endophytes are symbionts that live in healthy plants and potentially improve the health of plant holobionts. Here, we investigated the bacterial endophyte community of Citrus reticulata grown in the northern Persian Gulf. Bacteria were isolated seasonally from healthy trees (root, stem, bark, trunk, leaf, and crown tissues) in four regions of Hormozgan province (i.e., Ahmadi, Siyahoo, Sikhoran, Roudan), a subtropical hot region in Iran. A total of 742 strains from 17 taxa, 3 phyla, and 5 orders were found, most of which belonged to Actinobacteria (Actinobacteriales) as the dominant group, followed by Firmicutes (Bacillales), Proteobacteria (Sphingomonadales, Rhizobiales), and Cyanobacteria (Synechoccales). The genera included Altererythrobacter, Arthrobacter, Bacillus, Cellulosimicrobium, Curtobacterium, Kocuria, Kytococcus, Methylopila, Mycobacterium, Nocardioides, Okiabacterium, Paracraurococcus, and Psychrobacillus. The most frequently occurring species included Psychrobacillus psychrodurans, Kytococcus schroetri, and Bacillus cereus. In addition, the overall colonization frequency and variability of endophytes were higher on the trunks. The leaves showed the lowest species variability in all sampling periods. The frequency of endophyte colonization was also higher in summer. The Shannon-Wiener (H') and Simpson indices varied with all factors, i.e., region, season, and tissue type, with the maximum in Roudan. Furthermore, 52.9% of the strains were capable of nitrogen fixation, and 70% produced antagonistic hydrogen cyanide (HCN). Thus, C. reticulata harbors a variety of bioactive bacterial endophytes that could be beneficial for host fitness in such harsh environments.
- MeSH
- Bacteria * classification metabolism isolation & purification genetics MeSH
- Biodiversity MeSH
- Citrus * microbiology MeSH
- Endophytes * classification isolation & purification metabolism genetics MeSH
- Nitrogen Fixation * MeSH
- Phylogeny MeSH
- Plant Leaves microbiology MeSH
- Microbiota * MeSH
- RNA, Ribosomal, 16S genetics MeSH
- Seasons MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Iran MeSH
Nově se do terapie tuberkulózy v dětském věku dostávají moderní léky, tablety rozpustné v ústech. léky jsou k dispozici buď v kombinované formě (dohromady izoniasid + rifampicin + pyrazinamid nebo izoniasid + rifampicin) nebo samostatně (izoniasid a etambutol). léčba je indikována převážně pro nejmladší věkové skupiny.
Contemporary pharmaceutical agents, specifically orodispersible tablets, are now entering the management of tuberculosis in children. the pharmaceuticals are available in two forms: either in combination (isoniaside+rifamp icin+pyrazinamide, isoniazid+rifampicin) or as monotherapy (isoniaside, ethambutol). the treatment is primarily indicated for the youngest age groups.
- MeSH
- Antitubercular Agents * administration & dosage pharmacology therapeutic use MeSH
- Administration, Oral MeSH
- Child MeSH
- Ethambutol administration & dosage pharmacology therapeutic use MeSH
- Isoniazid administration & dosage pharmacology therapeutic use MeSH
- Combined Modality Therapy * methods MeSH
- Dosage Forms MeSH
- Humans MeSH
- Rifampin administration & dosage pharmacology therapeutic use MeSH
- Tuberculosis diagnosis drug therapy MeSH
- Check Tag
- Child MeSH
- Humans MeSH
Doležalová k. problematika tuberkulózy a non-tuberkulózních mykobakterióz v pediatrii Tuberkulóza (tB) je infekční onemocnění způsobené Mycobacterium tuberculosis, které postihuje převážně plíce, ale může napadnout kterýkoli orgán. Vysoké riziko tB mají děti ze znevýhodněných sociálních podmínek, děti s rodinnou anamnézou tB, romské děti a migranti z oblastí s vysokou incidencí tB. s nadsázkou tedy můžeme říct, že tB je sociální onemocnění způsobené bakterií. diagnostika tB je založena na třech pilířích: 1. epidemiologická souvislost; pozitivní tuberkulinový kožní test (tst) a interferon gamma release (iGra) test; 3. radiologický nález. léčba tB spočívá v podávání kombinace antituberkulotik a řídí ji pneumolog nejlépe z centra dětské tB.(1) příbuznou nemocí jsou mykobakteriózy (non-tuberkulózní mykobakterie – ntM). u dětí je nejčastěji vídáme v batolecím věku pod obrazem jednostranné krční lymfadenitidy, způsobené Mycobacterium avium. Výskyt ntM krční lymfadenitidy u dětí jednoznačně narostl po zrušení celoplošné kalmetizace.(2)
Doležalová k. pediatric tuberculosis and nontuberculous mycobacterial infections: current challenges and clinical insights Tuberculosis (tB) is an infectious disease caused by Mycobacterium tuberculosis. it primarily affects the lungs but can involve any organ system. children at higher risk include those from socioeconomically disadvantaged environments, with a family history of tB, of roma ethnicity, or migrants from regions with a high incidence of tuberculosis. therefore, tB can be regarded as a social disease caused by a bacterium. diagnosis is based on three main pillars: the presence of an epidemiological link, a positive tuberculin skin test (tst) and interferon gamma release assay (iGra), and characteristic radiological findings. treatment consists of a combination of antituberculosis drugs and is best managed by a pulmonologist, ideally within a specialized pediatric tB center. non-tuberculous mycobacterial infections (ntM) in children most commonly occur in toddlers, typically presenting as unilateral cervical lymphadenitis caused by Mycobacterium avium. the incidence of ntM lymphadenitis in children has clearly increased since the discontinuation of nationwide BcG vaccination.
- MeSH
- Antitubercular Agents pharmacology therapeutic use MeSH
- Mycobacterium Infections, Nontuberculous * diagnosis drug therapy MeSH
- Child MeSH
- Infant MeSH
- Humans MeSH
- Adolescent MeSH
- Nontuberculous Mycobacteria pathogenicity MeSH
- Lung diagnostic imaging microbiology pathology MeSH
- Child, Preschool MeSH
- Tuberculosis * diagnosis drug therapy classification microbiology mortality MeSH
- Check Tag
- Child MeSH
- Infant MeSH
- Humans MeSH
- Adolescent MeSH
- Child, Preschool MeSH
- Publication type
- Review MeSH
A Mycobacterium smegmatis transcriptional regulator, MSMEG_5850, and its ortholog in M. tuberculosis, rv0775 were annotated as putative TetR Family Transcriptional Regulators. Our previous study revealed MSMEG_5850 is involved in global transcriptional regulation in M. smegmatis and the presence of gene product supported the survival of bacteria during nutritional starvation. Phylogenetic analysis showed that MSMEG_5850 diverged early in comparison to its counterparts in virulent strains. Therefore, the expression pattern of MSMEG_5850 and its counterpart, rv0775, was compared during various in-vitro growth and stress conditions. Expression of MSMEG_5850 was induced under different environmental stresses while no change in expression was observed under mid-exponential and stationary phases. No expression of rv0775 was observed under any stress condition tested, while the gene was expressed during the mid-exponential phase that declined in the stationary phase. The effect of MSMEG_5850 on the survival of M. smegmatis under stress conditions and growth pattern was studied using wild type, knockout, and supplemented strain. Deletion of MSMEG_5850 resulted in altered colony morphology, biofilm/pellicle formation, and growth pattern of M. smegmatis. The survival rate of wild-type MSMEG_5850 was higher in comparison to knockout under different environmental stresses. Overall, this study suggested the role of MSMEG_5850 in the growth and adaptation/survival of M. smegmatis under stress conditions.
- MeSH
- Bacterial Proteins * genetics metabolism MeSH
- Biofilms growth & development MeSH
- Phylogeny MeSH
- Stress, Physiological * MeSH
- Microbial Viability MeSH
- Mycobacterium smegmatis * genetics growth & development physiology metabolism MeSH
- Gene Expression Regulation, Bacterial MeSH
- Transcription Factors * genetics metabolism MeSH
- Publication type
- Journal Article MeSH
Rare and unknown actinobacteria from unexplored environments have the potential to produce new bioactive molecules. This study aimed to use 16 s rRNA metabarcoding to determine the composition of the actinobacterial community, particularly focusing on rare and undescribed species, in a nature reserve within the Brazilian Cerrado called Sete Cidades National Park. Since this is an inaccessible area without due legal authorization, it is understudied, and, therefore, its diversity and biotechnological potential are not yet fully understood, and it may harbor species with groundbreaking genetic potential. In total, 543 operational taxonomic units (OTUs) across 14 phyla were detected, with Actinobacteria (41.2%), Proteobacteria (26.5%), and Acidobacteria (14.3%) being the most abundant. Within Actinobacteria, 107 OTUs were found, primarily from the families Mycobacteriaceae, Pseudonocardiaceae, and Streptomycetaceae. Mycobacterium and Streptomyces were the predominant genera across all samples. Seventeen rare OTUs with relative abundance < 0.1% were identified, with 82.3% found in only one sample yet 25.5% detected in all units. Notable rare and transient genera included Salinibacterium, Nocardia, Actinomycetospora_01, Saccharopolyspora, Sporichthya, and Nonomuraea. The high diversity and distribution of Actinobacteria OTUs indicate the area's potential for discovering new rare species. Intensified prospection on underexplored environments and characterization of their actinobacterial diversity could lead to the discovery of new species capable of generating innovative natural products.
- MeSH
- Actinobacteria * chemistry classification genetics isolation & purification MeSH
- Biodiversity MeSH
- Metagenome MeSH
- Soil chemistry MeSH
- Soil Microbiology * MeSH
- RNA, Ribosomal, 16S analysis MeSH
- DNA Barcoding, Taxonomic MeSH
- Parks, Recreational MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Brazil MeSH
Non-tuberculous mycobacteria (NTM) are pathogens that are widely distributed in the environment and cause increasing rates of human infections. High levels of antimicrobial resistance shown by these bacteria complicate infection management and limit treatment options. The complex structure of cell walls and features such as biofilm formation are responsible for intrinsic resistance in NTMs. Antimicrobial resistance can be explained by four basic mechanisms: (i) limitation of drug uptake, meaning antibiotic entry is limited due to the presence of a hydrophobic and low permeability cell wall and a small number of porin channels, (ii) enzymatic modification of antibiotics, (iii) target site modification, (iv) efflux pumps, which prevent drug accumulation by actively expelling antibiotics from the cell and reduce treatment efficacy. For effective management of NTM infections, detailed understanding of resistance mechanisms, development of species-specific treatment protocols, and discovery of new antimicrobial agents are of great importance. In this review, the mechanisms causing drug resistance in NTMs will be reviewed.
- MeSH
- Anti-Bacterial Agents * pharmacology MeSH
- Mycobacterium Infections, Nontuberculous * microbiology drug therapy MeSH
- Drug Resistance, Bacterial * MeSH
- Bacterial Proteins metabolism genetics MeSH
- Biofilms MeSH
- Cell Wall metabolism MeSH
- Humans MeSH
- Nontuberculous Mycobacteria * drug effects genetics metabolism MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
Drug resistance is a growing problem for many pathogens, including mycobacteria. Small heterocyclic molecules are among the leading scaffolds for developing potential antimycobacterial agents. Therefore, based on the molecular hybridization approach, we have prepared an extensive series of N-substituted 5-(3,5-dinitrophenyl)-1,3,4-oxadiazol-2-amine derivatives. We also investigated their isosteres and acyclic synthetic precursors. The compounds were evaluated for their in vitro activity against Mycobacterium tuberculosis (Mtb) H37Rv, a panel of multidrug- and extensively drug-resistant Mtb isolates and two nontuberculous mycobacterial strains (NTM; M. avium and M. kansasii). The ability to inhibit mycobacterial growth was quantified using minimum inhibitory concentration (MIC) values. Many compounds achieved MIC values ≤ 0.03 μM for NTM and Mtb, regardless of their resistance profile. The highest activity was associated with oxadiazole and thiadiazole scaffolds with benzylamino or C5-C9 alkylamino substitution. The experimentally confirmed mechanism of action of these compounds consists of disruption of mycobacterial cell wall biosynthesis via inhibition of decaprenylphosphoryl-β-D-ribose 2'-epimerase (DprE1). In vitro toxicity evaluation was performed in a hepatocyte model (HepG2), while in vivo toxicity was evaluated using Danio rerio embryos. These findings identify a promising new chemotype with potent, broad-spectrum and selective antimycobacterial activity, including efficacy against resistant strains, and support its further development as a potential therapeutic candidate.
- MeSH
- Antitubercular Agents * pharmacology chemical synthesis chemistry toxicity MeSH
- Zebrafish MeSH
- Humans MeSH
- Microbial Sensitivity Tests MeSH
- Mycobacterium tuberculosis drug effects MeSH
- Oxadiazoles * pharmacology chemical synthesis chemistry MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
x
x
- MeSH
- Antitubercular Agents therapeutic use MeSH
- Emigrants and Immigrants MeSH
- Communicable Disease Control methods MeSH
- Humans MeSH
- Tuberculosis * epidemiology drug therapy MeSH
- Refugees MeSH
- Check Tag
- Humans MeSH
- Geographicals
- Ukraine MeSH
x
x
- MeSH
- Epidemiologic Factors MeSH
- Humans MeSH
- Tuberculosis * epidemiology MeSH
- Check Tag
- Humans MeSH
- Geographicals
- Czech Republic MeSH
