Microbiology spectrum最新文献

{"title":"Putative evolution of <i>Myxococcus fulvus</i> 124B02 plasmid pMF1 from a chromosomal segment in another <i>Myxococcus</i> species.","authors":"Shruti Jain, Gaurav Sharma","doi":"10.1128/spectrum.01206-24","DOIUrl":"https://doi.org/10.1128/spectrum.01206-24","url":null,"abstract":"<p><p>Myxobacteria or order Myxococcales (old nomenclature) or phylum Myxococcota (new terminology) are fascinating organisms well known for their diverse peculiar physiological, taxonomic, and genomic properties. Researchers have long sought to identify plasmids within these organisms, yet thus far, only two organisms from different families have been found to harbor a plasmid. This study delves into the putative evolution of one of these plasmids, i.e., pMF1 present in <i>Myxococcus fulvus</i> 124B02 in the suborder Cystobacterineae and family Myxococcaceae. Here, we first reannotated the pMF1 plasmid genome sequence and identified two additional open reading frames or putative genes which were not annotated until now. We further reported that all pMF1 plasmid genes depict homology with <i>Myxococcus stipitatus</i> CYD1 draft genome (contig 28) and a chromosomal segment of <i>M. stipitatus</i> DSM14675 in a syntenic manner, implying the presence of plasmid-like structure in <i>M. stipitatus</i> CYD1, integrated into its chromosome. To comprehend the relationship among these three species, we conducted phylogenetic analyses using 16S and concatenated housekeeping genes and genome-to-genome distance calculator (GGDC) analysis, which confirmed that <i>M. stipitatus</i> CYD1 is a distinct and novel species within the genus <i>Myxococcus</i>. Overall, this comparative genomic study sheds light on the putative emergence of the pMF1 plasmid from a common ancestor of closely related yet distinct species, <i>M. stipitatus</i> CYD1, possibly through the partition from its chromosome as a segment.IMPORTANCEMyxobacteria are not well known to have plasmids. Until now, only two organisms have been shown to have plasmids, raising a pertinent question about how these plasmids evolved randomly within the phylum Myxococcota. The study presented in this manuscript delves into the emergence of the pMF1 plasmid found in <i>Myxococcus fulvus</i> 124B02, a member of the suborder Cystobacterineae and family Myxococcaceae. Our research addresses this intriguing topic of plasmid identification and evolution within myxobacteria, which are a group of fascinating organisms that have garnered significant interest due to their diverse physiological, taxonomic, and genomic properties.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0120624"},"PeriodicalIF":3.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142639189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional insights of novel Bathyarchaeia reveal metabolic versatility in their role in peatlands of the Peruvian Amazon.","authors":"Michael J Pavia, Arkadiy I Garber, Sarah Avalle, Franco Macedo-Tafur, Rodil Tello-Espinoza, Hinsby Cadillo-Quiroz","doi":"10.1128/spectrum.00387-24","DOIUrl":"https://doi.org/10.1128/spectrum.00387-24","url":null,"abstract":"<p><p>The decomposition of soil organic carbon within tropical peatlands is influenced by the functional composition of the microbial community. In this study, building upon our previous work, we recovered a total of 28 metagenome-assembled genomes (MAGs) classified as Bathyarchaeia from the tropical peatlands of the Pastaza-Marañón Foreland Basin (PMFB) in the Amazon. Using phylogenomic analyses, we identified nine genus-level clades to have representatives from the PMFB, with four forming a putative novel family (\"<i>Candidatus</i> Paludivitaceae\") endemic to peatlands. We focus on the <i>Ca</i>. Paludivitaceae MAGs due to the novelty of this group and the limited understanding of their role within tropical peatlands. Functional analysis of these MAGs reveals that this putative family comprises facultative anaerobes, possessing the genetic potential for oxygen, sulfide, or nitrogen oxidation. This metabolic versatility can be coupled to the fermentation of acetoin, propanol, or proline. The other clades outside <i>Ca</i>. Paludivitaceae are putatively capable of acetogenesis and <i>de novo</i> amino acid biosynthesis and encode a high amount of Fe³⁺ transporters. Crucially, the <i>Ca</i>. Paludivitaceae are predicted to be carboxydotrophic, capable of utilizing CO for energy generation or biomass production. Through this metabolism, they could detoxify the environment from CO, a byproduct of methanogenesis, or produce methanogenic substrates like CO₂ and H₂. Overall, our results show the complex metabolism and various lineages of Bathyarchaeia within tropical peatlands pointing to the need to further evaluate their role in these ecosystems.</p><p><strong>Importance: </strong>With the expansion of the <i>Candidatus</i> Paludivitaceae family by the assembly of 28 new metagenome assembled genomes, this study provides novel insights into their metabolic diversity and ecological significance in peatland ecosystems. From a comprehensive phylogenic and functional analysis, we have elucidated their putative unique facultative anaerobic capabilities and CO detoxification potential. This research highlights their crucial role in carbon cycling and greenhouse gas regulation. These findings are essential for resolving the microbial processes affecting peat soil stability, offering new perspectives on the ecological roles of previously underexplored and underrepresented archaeal populations.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0038724"},"PeriodicalIF":3.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142624120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shifts in bacterial community composition during symbiotic seed germination of a terrestrial orchid and effects on protocorm development.","authors":"Zeyu Zhao, Luna Yang, Yaoyao Wang, Xin Qian, Gang Ding, Hans Jacquemyn, Xiaoke Xing","doi":"10.1128/spectrum.02185-24","DOIUrl":"https://doi.org/10.1128/spectrum.02185-24","url":null,"abstract":"<p><p>Fungi and bacteria often occupy very similar niches; they interact closely with each other, and bacteria can provide direct or indirect benefits to plants that form mutualistic interactions with fungi. In orchids, successful seed germination largely depends on compatible mycorrhizal fungi, but whether and how bacteria contribute to seed germination and protocorm development remains largely unknown. Here, we performed field and laboratory experiments to assess the potential role of bacteria in mediating seed germination and protocorm development in the terrestrial orchid <i>Gymnadenia conopsea</i>. Our results suggested that bacterial and fungal communities differ between developmental stages in the germination process. The diversity of bacterial and fungal communities and their interaction network in germinating seeds (Stage 1) differed significantly from those in later developmental stages (Stages 2-5). <i>Pseudomonas</i> gradually became the dominant bacterial group as the protocorms matured and showed a positive association with Ceratobasidiaceae fungi. Seed germination tests <i>in vitro</i> demonstrated that co-inoculation of <i>Ceratobasidium</i> sp. GS2 with <i>Pseudomonas</i> isolates significantly improved protocorm growth and development, suggesting that the observed increase in <i>Pseudomonas</i> abundance during protocorm development directly or indirectly improves the growth of germinating seeds. Overall, our findings indicate that bacteria may exert non-negligible effects on seed germination of orchids and, therefore, offer valuable perspectives for future strategies for conservation and cultivating orchid species.</p><p><strong>Importance: </strong>It is well known that orchid seeds depend on mycorrhizal fungi to supply the necessary nutrients that support germination in natural environments. Apart from fungi, bacteria may also be involved in the germination process of orchid seeds, but so far, their role has not been intensively studied. This research provides evidence that bacterial community composition changes during seed germination of the terrestrial orchid <i>Gymnadenia conopsea</i>. Interestingly, <i>in vitro</i> experiments showed that <i>Pseudomonas</i> spp., which were the most dominant bacteria in the later germination stages, improved protocorm growth. These results suggest that bacteria contribute to the germination of orchid seeds, which may open new perspectives to apply bacteria as a biofertilizer in the introduction and restoration of <i>G</i>. <i>conopsea</i> populations.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0218524"},"PeriodicalIF":3.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142624151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification and biological characteristics of <i>Fusarium tobaccum</i> sp. nov., a novel species causing tobacco root rot in Jilin Province, China.","authors":"Zhao Xie, Chong Gao, Xiaoyan Zhang, Mengzhu Du, Jun Wang, Xue Wang, Baohui Lu, Changqing Chen, Lina Yang, Yanjing Zhang, Jie Gao","doi":"10.1128/spectrum.00925-24","DOIUrl":"https://doi.org/10.1128/spectrum.00925-24","url":null,"abstract":"<p><p>Fusarium wilt of tobacco (FWT), caused by <i>Fusarium</i> spp., has emerged as a severe threat to tobacco production in China. In all, 132 isolates of <i>Fusarium</i> were isolated from tobacco and pathogenic to tobacco-causing FWT in Jilin Province, China. In this study, we identified 7 of 132 isolates as a novel species <i>Fusarium tobaccum</i> sp. nov. Zhao Xie & Jie Gao, using multi-gene phylogenetic analyses of translation elongation factor (<i>tef1</i>), β-tubulin (<i>tub2</i>), calmodulin (<i>cmdA</i>), and RNA polymerase II second largest subunit (<i>rpb2</i>) genes, along with subtle morphological differences. Isolates of <i>F. tobaccum</i> sp. nov. were clustered in a distinct branch in the maximum parsimony phylogenetic tree generated from the sequences of <i>tef1-rpb2-tub2-cmdA</i> and can be distinguished from closely related species <i>F. cugenangense</i>, <i>F. callistephi</i>, and <i>F. elaeidis</i>. The morphological characteristics of <i>F. tobaccum</i> sp. nov. are distinct from other <i>Fusarium</i> species. <i>F. tobaccum</i> sp. nov. exhibits abundant aerial mycelia and pigment production on potato dextrose agar (PDA), microconidia with 0-1 septa, and macroconidia with 2-5 septa on carnation leaf-piece agar (CLA), and produces abundant chlamydospores on Spezieller Nährstoffarmer agar (SNA) and CLA. The mycelia of <i>F. tobaccum</i> exhibited optimal growth at a pH of 7.1 and a temperature of 23.6°C. Sucrose and NaNO₃ significantly promoted the mycelial growth of <i>F. tobaccum</i>. PD medium was optimal for total sporulation. However, the sporulation ratios of the macrospores of <i>F. tobaccum</i> in PD, SN, and CMC were relatively low (0.48%, 2.51%, and 2.16%, respectively). These findings provided valuable insights into the morphological and biological characteristics of <i>F. tobaccum</i>.IMPORTANCE<i>Fusarium</i> wilt of tobacco (FWT) is a prevalent issue in tobacco-growing regions globally, leading to significant losses in yield and quality. This study identified <i>F. tobaccum</i> sp. nov., a novel species of <i>Fusarium</i> causing FWT in China. The identification was based on multi-gene phylogenetic analyses and morphological characteristics. The effects of temperature, pH, carbon source, nitrogen source, medium, and light on the mycelial growth of <i>F. tobaccum</i> sp. nov. were determined. These findings might contribute to future research on the pathogenic mechanisms of this novel species and the development of strategies to control FWT.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0092524"},"PeriodicalIF":3.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142624133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative MODS-Wayne assay for rapid detection of pyrazinamide resistance in <i>Mycobacterium tuberculosis</i> from sputum samples.","authors":"Emily Toscano-Guerra, Roberto Alcántara, Katherine Lozano Untiveros, Robert Gilman, Louis Grandjean, Mirko Zimic, Patricia Sheen","doi":"10.1128/spectrum.00471-24","DOIUrl":"https://doi.org/10.1128/spectrum.00471-24","url":null,"abstract":"<p><p>Tuberculosis (TB) remains a significant global health challenge, exacerbated by the emergence of drug-resistant strains, such as those resistant to pyrazinamide (PZA). The current scarcity of affordable and precise quantitative diagnostic tests for PZA resistance underscores the urgent need for more accessible diagnostic tools. We evaluated PZA susceptibility in 264 TB-positive samples by quantifying pyrazinoic acid (POA) production, using both the MODS-Wayne qualitative assay and our newly developed quantitative approach (MODS-WQ). The MODS-WQ was assessed in 7H9 medium (MODS-WQ_7H9) or citrate buffer (MODS-WQ_CB), with POA levels measured via spectrophotometry against a calibration curve. PZA susceptibility determinations were based on a composite reference standard. Associations between POA levels and pyrazinamidase mutations were explored. The composite standard detected PZA resistance in 23.5% of the samples, which accounts for 62.8% of the multidrug-resistant (MDR) samples. The MODS-WQ established specific POA cutoffs of 123.25 µM for MODS-WQ_7H9 and 664.7 µM for MODS-WQ_CB, with sensitivities of 81.3% and 92.3% and specificities of 77.2% and 95.9%, respectively. Notably, samples with mutations in the pyrazinamidase metal-binding site exhibited significantly lower POA levels compared with mutations in the enzyme periphery. Furthermore, a significant correlation was found between POA production and PZA resistance, Bactec Growth Index, and minimum inhibitory concentration (MIC) values. This study presents a novel, direct, and accessible susceptibility test for PZA resistance that quantifies POA, enhancing the detection capabilities for this condition. The citrate-buffered MODS-WQ assay demonstrated high sensitivity and specificity for quantifying POA, confirming that POA production is a reliable indicator of PZA resistance.</p><p><strong>Importance: </strong>PZA susceptibility testing continues to be a challenge, particularly in countries with high TB incidence. In response to this pressing need, we have developed a quantitative MODS-Wayne (MODS-WQ) assay. This approach offers a direct and cost-effective solution representing a significant advancement in TB diagnostics, particularly benefiting resource-limited laboratories, primarily in developing regions. The MODS-WQ assay stands out for its ability to quantify pyrazinoic acid (POA) production, as a reliable indicator of PZA resistance. Unlike traditional qualitative assays, MODS-WQ eliminates the inherent subjectivity in interpretation, providing more accurate and actionable results. Moreover, the MODS-WQ approach accounts for critical factors influencing PZA resistance, including enzymatic efficiency and efflux pump activity. By integrating these factors into the detection process, our methodology offers a comprehensive understanding of PZA resistance levels, enabling tailored treatment strategies for patients.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0047124"},"PeriodicalIF":3.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142624147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antibiotic resistance and serotype distribution of <i>Shigella</i> strains in Bangladesh over the period of 2014-2022: evidence from a nationwide hospital-based surveillance for cholera and other diarrheal diseases.","authors":"Mokibul Hassan Afrad, Md Taufiqul Islam, Yasmin Ara Begum, Md Saifullah, Faisal Ahmmed, Zahid Hasan Khan, Zakir Hossain Habib, Ahmed Nawsher Alam, Tahmina Shirin, Taufiqur Rahman Bhuiyan, Edward T Ryan, Ashraful Islam Khan, Firdausi Qadri","doi":"10.1128/spectrum.00739-24","DOIUrl":"https://doi.org/10.1128/spectrum.00739-24","url":null,"abstract":"<p><p>The objective of this study was to assess the prevalence, antimicrobial resistance patterns, and risk factors linked to <i>Shigella</i> infections through a nationwide hospital-based diarrheal disease surveillance in Bangladesh. From May 2014 to May 2022, from a systematic sentinel surveillance of <i>Shigella</i> infections in over 10 hospitals across Bangladesh, stool specimens were collected from patients with acute watery diarrhea and tested for <i>Shigella</i> species by microbiological culture. The susceptibility to antibiotics was tested using the disk diffusion method. Structured questionnaires were used to collect participants' socioeconomic status and clinical, sanitation, and food history. Out of 24,357 stool specimens, 1.8% were positive for <i>Shigella</i> species, with a higher prevalence among males (58%). Children in the 6-17 age group were found to be at the highest risk of <i>Shigella</i> infections. The most prevalent serotype was <i>Shigella flexneri</i> (79.5%), followed by <i>Shigella sonnei. S. flexneri</i> serotype 2a was the most common (63.3%) among all <i>Shigella</i> serotypes. Antibiotic susceptibility testing showed over 99% of isolates resistant or with intermediate susceptibility to one of the seven antibiotics tested. About 96% of <i>S. flexneri</i> and all <i>S. sonnei</i> isolates demonstrated resistance to at least one quinolone class of antibiotics, particularly ciprofloxacin or nalidixic acid. <i>S. sonnei</i> showed higher antibiotic resistance and multidrug resistance compared to <i>S. flexneri</i>. The high level of resistance to ciprofloxacin highlights the need for more prudent use of this antibiotic and improved hygiene and sanitation. The study emphasized the importance of regular monitoring of drug resistance to effectively manage <i>Shigella</i> infections. These findings may provide the epidemiological evidence for conducting future appropriate <i>Shigella</i> vaccine clinical trials in Bangladesh.</p><p><strong>Importance: </strong>This nationwide study in Bangladesh assessed <i>Shigella</i> infections from 2014 to 2022 from clinical samples. <i>S. flexneri</i> was predominant, with concerning antibiotic resistance, notably to ciprofloxacin and nalidixic acid in over 96% of isolates. This emphasizes the urgency of prudent antibiotic use and improved hygiene. The findings provide crucial antimicrobial resistance patterns of <i>Shigella</i> species, highlighting the need for ongoing resistance monitoring and potentially informing future vaccine trials.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0073924"},"PeriodicalIF":3.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142624086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inhibition of protein kinase D and its substrate phosphatidylinositol-4 kinase III beta blocks common human coronavirus replication.","authors":"Huijuan Han, Huan Liu, Rebbeca Steiner, Zhijun Zhao, Zheng-Gen Jin","doi":"10.1128/spectrum.01501-24","DOIUrl":"https://doi.org/10.1128/spectrum.01501-24","url":null,"abstract":"<p><p>Coronavirus disease 2019 (COVID-19) is caused by the infection of a coronavirus, named as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Coronaviruses can be replicated in the infected host cells. Coronavirus replication involves various steps, including membrane fusion, peri-nuclear particle formation, and matrix vesicle transport to the cell membrane <i>via</i> the endoplasmic reticulum-Golgi-lysosome route. Recent studies have suggested that protein kinase D (PKD) plays a crucial role in regulation of vesicle formation and trafficking in the trans-Golgi network (TGN). Thus, we hypothesize that inhibiting PKD and its associated pathway could be an effective strategy to limit viral replication. Here, we report that molecular and pharmacological inhibition of PKD and its substrate phosphatidylinositol-4 kinase III beta (PI4KIIIβ) significantly diminishes the replication of common human coronaviruses. Specifically, we found that the PKD-silencing siRNA and the PKD inhibitor CRT0066101 have broad-spectrum antiviral activity against HCoV-OC43, HCoV-NL63, and HCoV-229E in cultured cells. Mechanistic studies revealed that the deactivation of PKD reduced the activation of PI4KIIIβ, thereby blocking the transport of viral particles in the host cells. Furthermore, the PI4KIIIβ inhibitor, BQR695, also exhibited antiviral activity against those coronaviruses. In conclusion, PKD and its substrate, PI4KIIIβ, may serve as novel antiviral targets for human coronaviruses and warrant further investigation.</p><p><strong>Importance: </strong>Human coronaviruses can lead to a range of clinical symptoms, from asymptomatic infection to severe illness and death, with a limited array of antiviral drugs available. Protein kinase D (PKD) is involved in various cellular processes, such as cell proliferation, apoptosis, and membrane fission of the Golgi apparatus. However, the specific role of PKD in the human coronavirus life cycle remains unclear. In this study, we found that PKD inhibitors effectively attenuated human coronavirus replication at the trans-Golgi network (TGN) stage in the viral life cycle. Furthermore, inhibiting PKD reduced PI4KIIIβ activation, thereby blocking viral replication in the host cells. Importantly, PI4KIIIβ inhibitors also blocked human coronavirus replication. Thus, PKD may represent a promising therapeutic target against both current circulating and future emerging coronaviruses.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0150124"},"PeriodicalIF":3.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142624138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genomic characteristics of <i>Salmonella enterica</i> serovar Blockley.","authors":"Hidemasa Izumiya, Chien-Shun Chiou, Masatomo Morita, Toshio Sato, Akio Noguchi, Tetsuya Harada, Yukihiro Akeda, Makoto Ohnishi","doi":"10.1128/spectrum.02048-24","DOIUrl":"https://doi.org/10.1128/spectrum.02048-24","url":null,"abstract":"<p><p>Non-typhoidal <i>Salmonella</i> (NTS) is a significant cause of foodborne illness worldwide, with increasing antimicrobial resistance posing a public health concern. <i>Salmonella enterica</i> serovar Blockley (<i>S</i>. Blockley) is relatively uncommon, and its antimicrobial resistance profile and population structure have been understudied. This study presents a comprehensive genomic analysis of 264 <i>S</i>. Blockley isolates from diverse geographical regions to elucidate antimicrobial resistance patterns and population structure. Bayesian analysis classified these genomes into 10 distinct groups (BAPS A to BAPS J), further categorized into two lineages, R and S. Lineage R comprised six BAPS clusters (BAPSs A-F), predominantly found in Asia and Africa, all of which harbored the azithromycin resistance gene <i>mph(A</i>) and other resistance determinants. In contrast, lineage S, lacking <i>mph(A</i>), comprised the remaining four BAPS clusters, which were primarily found in Europe and the Americas. Several types of mutations in <i>gyrA</i> were found in lineage R, which were specific to BAPS clusters. These BAPS clusters exhibited distinct geographic distributions, with BAPS B, BAPS D, and BAPS E unique to China, Taiwan, and Japan, respectively, while BAPS H and BAPS I were predominantly found in the United States. Temporal phylogenetic analysis suggested that lineage R diverged in the 1980s, with notable microevolutionary changes. The presence of a genomic island with <i>mph(A</i>), <i>aph(3')-Ia</i>, <i>aph(3\")-Ib</i>, <i>aph(6)-Id</i>, and <i>tet(A</i>) in lineage R underscores the public health threat, highlighting a need for continuous surveillance.IMPORTANCEAntimicrobial resistance in <i>Salmonella</i> is a global public health concern. In this study, we focused on serovar Blockley, and a whole-genome analysis revealed its global population structure. The results revealed the existence of azithromycin-resistant strains, which were characterized both phylogenetically and geographically. The resistance genes were transmitted via genomic islands, and their micro-scale evolution was also revealed. Our findings are the first to reveal the dissemination of antimicrobial resistance genes, including azithromycin, in serovar Blockley, and provide valuable insights into understanding the spread of antimicrobial resistance.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0204824"},"PeriodicalIF":3.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142624124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Erratum for Prommi et al., \"Co-resistance to isoniazid and second-line anti-tuberculosis drugs in isoniazid-resistant tuberculosis at a tertiary care hospital in Thailand\".","authors":"Ajala Prommi, Kanphai Wongjarit, Suthidee Petsong, Ubonwan Somsukpiroh, Kiatichai Faksri, Kamon Kawkitinarong, Sunchai Payungporn, Suwatchareeporn Rotcheewaphan","doi":"10.1128/spectrum.02419-24","DOIUrl":"https://doi.org/10.1128/spectrum.02419-24","url":null,"abstract":"","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0241924"},"PeriodicalIF":3.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142624108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pullulan nanoparticles inhibit the pathogenicity of <i>Candida albicans</i> by regulating hypha-related gene expression.","authors":"Sujin Hong, Seo-Kyung Kim, Christine H Chung, Cheol-Heui Yun, Junho Lee, Chong-Su Cho, Won-Ki Huh","doi":"10.1128/spectrum.01048-24","DOIUrl":"https://doi.org/10.1128/spectrum.01048-24","url":null,"abstract":"<p><p><i>Candida albicans</i> is a prevalent opportunistic pathogenic fungus that resides in the skin and gastrointestinal (GI) tract of humans. Under specific conditions, <i>C. albicans</i> cells transition from a commensal to a pathogenic state, leading to both superficial and invasive infections. Although systemic candidiasis poses a life-threatening risk, a limited number of antifungal drugs are employed for its treatment. Moreover, the emergence of resistant strains to antifungal agents underscores the pressing need for new treatment options. In this study, we propose the use of polysaccharide nanoparticles as a strategy for treating candidiasis. We synthesized phthalic pullulan nanoparticles (PPNPs) and examined their ability to inhibit the pathogenicity of <i>C. albicans</i>. We observed that PPNPs inhibit hyphal growth, adhesion to abiotic surfaces, and biofilm formation of <i>C. albicans</i> in a dose-dependent manner. This inhibitory effect is mediated by transcriptional modulation, particularly the downregulation of hypha-related genes and the upregulation of stress-responsive genes, involving the Ras/cAMP/PKA signaling pathway. Furthermore, we observed that PPNPs inhibit the adhesion of <i>C. albicans</i> to human epithelial cells without inducing toxicity in human cells. In addition, PPNPs inhibited the <i>in vivo</i> pathogenicity of <i>C. albicans</i> in <i>Caenorhabditis elegans</i>, suggesting an antagonistic effect on candidiasis. Our findings suggest that PPNPs exhibit inhibitory effects on <i>C. albicans</i> biofilm formation and <i>in vivo</i> pathogenicity, indicating their potential as a novel therapeutic agent for candidiasis.</p><p><strong>Importance: </strong>The pathogenic process of <i>Candida albicans</i>, the primary causative species of candidiasis, involves hyphal growth, biofilm formation, and secretion of virulence factors. Of these factors, the biofilm, created by the secretion of extracellular matrix from adherent cells, shields cells from external threats, enabling them to withstand high concentrations of antifungal agents. Therefore, suppressing biofilm formation is a crucial aspect of combating candidiasis. This study developed phthalic pullulan nanoparticles (PPNPs) as a novel material for inhibiting <i>C. albicans</i>' pathogenicity. PPNPs were internalized within <i>Candida</i> cells and reduced pathogenicity at the gene expression level, resulting in reduced <i>in vitro</i> biofilm formation, adhesion to human cells, and mortality of infected <i>Caenorhabditis elegans</i>. Moreover, PPNPs exhibited these effects without toxicity to human cells and host animals. These findings not only indicate that PPNPs can be employed to hinder <i>in vitro</i> biofilm formation but also suggest their potential as a novel treatment for candidiasis.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0104824"},"PeriodicalIF":3.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142624143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}