Microbiology spectrum最新文献

{"title":"Multidimensional insights into the biodiversity of <i>Streptomyces</i> in soils of China: a pilot study.","authors":"Ziguang Deng, Wei Yang, Tongtong Lin, Yaohai Wang, Xiaojing Hua, Xiaoyu Jiang, Junhao Chen, Dan Liu, Zhiqiang Ye, Yu Zhang, Michael Lynch, Hongan Long, Jiao Pan","doi":"10.1128/spectrum.01692-24","DOIUrl":"https://doi.org/10.1128/spectrum.01692-24","url":null,"abstract":"<p><p><i>Streptomyces,</i> a diverse group of filamentous bacteria found predominantly in soil, play a crucial role in nutrient cycling and produce many valuable secondary metabolites for the pharmaceutical industry. In this pilot study, we collected 19 soil samples from 14 provinces in China to preliminarily investigate the biodiversity and genetic structure of <i>Streptomyces</i> in soils of China from different dimensions, using recently developed cost-efficient amplicon and whole-genome library preparation methods. Amplicon analysis showed that Actinobacteria were among the most abundant bacteria, with 0.3% of amplicon sequence variants (ASVs) belonging to <i>Streptomyces</i>. Meanwhile, we successfully isolated 136 <i>Streptomyces</i> natural strains and assembled their genomes, including 26 previously unreported species, underscoring the need for further exploration of soil <i>Streptomyces</i> in China. Population genetics analysis revealed that homologous recombination may primarily drive the extensive genetic diversity observed in <i>Streptomyces</i>, as well as a complex population structure. Complementing this, pan-genome analysis shed light on gene diversity within <i>Streptomyces</i> and led to the discovery of rare genes, further emphasizing the vast genetic diversity of this genus. Additionally, multiple metabolic gene clusters were found in these <i>Streptomyces</i> strains, as well as some potentially unique or uncommon ones were found. These findings not only highlight the biological and metabolic diversity of <i>Streptomyces</i> but also provide a technical framework for future studies on the global biodiversity and evolution of this genus.</p><p><strong>Importance: </strong><i>Streptomyces</i>, a prominent group of Actinobacteria, holds significant importance in ecosystems and biotechnology due to their diverse array of metabolic products. However, research on the biodiversity of soil <i>Streptomyces</i> across extensive geographical scales in China has been limited, and their genetic diversity has rarely been evaluated using modern population genetics principles. This pilot study successfully addresses these gaps by conducting a preliminary exploration on the biodiversity of <i>Streptomyces</i> in Chinese soils from multiple perspectives, providing valuable insights for a deeper understanding of their biodiversity and a novel technical framework for future large-scale explorations of its diversity.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0169224"},"PeriodicalIF":3.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143764313","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":"All parts of the WHO <i>Mycobacterium tuberculosis</i> mutation catalog need to be applied when evaluating its performance.","authors":"Sacha Laurent, Jody E Phelan, Leonid Chindelevitch, Timothy M Walker, Daniela M Cirillo, Anita Suresh, Timothy C Rodwell, Paolo Miotto, Claudio U Köser","doi":"10.1128/spectrum.02157-24","DOIUrl":"https://doi.org/10.1128/spectrum.02157-24","url":null,"abstract":"","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0215724"},"PeriodicalIF":3.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143763960","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":"Development of a neutralization assay and bioluminescent imaging mouse model for Dehong virus (DEHV) using a pseudovirus system.","authors":"Xuelian Wu, Fan Liu, Tao Li, Danfeng Li, Yanru Shen, Xiaoai Zhang, Shuo Liu, Qi Jiang, Chenyan Zhao, Jianhui Nie, Youchun Wang, Baomin Feng, Wei Liu, Weijin Huang","doi":"10.1128/spectrum.01557-24","DOIUrl":"https://doi.org/10.1128/spectrum.01557-24","url":null,"abstract":"<p><p>Dehong virus (DEHV) is an emerging filamentous virus of considerable interest. However, research involving DEHV remains limited, and no suitable models exist to investigate its pathogenicity or transmission. In this study, we developed an <i>in vitro</i> neutralization assay to detect DEHV-neutralizing antibodies, as well as an <i>in vivo</i> bioluminescent imaging mouse model based on a pseudovirus system. Our results confirmed that DEHV utilizes the Niemann-Pick disease, type C1 (NPC1) receptor for cellular entry. Additionally, the neutralization assay demonstrated that DEHV antiserum does not exhibit neutralizing activity against Mengla or Marburg viruses. This pseudovirus-based system provides a valuable platform for studying DEHV biology and evaluating therapeutic interventions.IMPORTANCEBats serve as natural reservoirs for diverse filoviruses across Africa, Europe, and East Asia; numerous strains circulate within these populations. Recently, Chinese researchers identified Dehong virus (DEHV), a novel filovirus carried by bats in China. However, the mechanisms underlying the pathogenicity and transmission of DEHV remain poorly understood. Similar to Ebola virus and Marburg virus (MARV), DEHV uses the Niemann-Pick disease, type C1 (NPC1) receptor for host cell invasion. In this study, we utilized a well-established in <i>vitro</i> neutralization assay to confirm that DEHV antiserum lacks neutralizing activity against Mengla and MARV pseudoviruses. Furthermore, we developed an innovative in <i>vivo</i> bioluminescent imaging mouse model using DEHV pseudovirus, which offers a visually intuitive and efficient platform for evaluating antiviral therapies and vaccine candidates. This model has considerable potential for advancing research into DEHV pathogenesis and treatment strategies.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0155724"},"PeriodicalIF":3.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143764292","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":"<i>Curtobacterium aetherium</i> sp. nov., a polyextremophilic plant pathogen isolated from the stratosphere.","authors":"Jovana Mijatović Scouten, Amy Smith, Adam J Ellington, Noelle C Bryan, Robert M Harveson, Brian H Kvitko, Brent C Christner","doi":"10.1128/spectrum.01774-24","DOIUrl":"https://doi.org/10.1128/spectrum.01774-24","url":null,"abstract":"<p><p>Although the high-altitude limit for microbial survival in the Earth-atmosphere system has remained a scientific curiosity and topic of study, the ecological significance of long-distance microbial dispersal in the atmosphere has been perceived to have marginal relevance. Here, we report the characterization of novel plant pathogenic species of <i>Curtobacterium</i> that were isolated from samples collected at altitudes ranging from 1.5 to 29 km above sea level. Whole genome-based phylogenies of three strains, paired with plant challenge assays, indicate that each is a previously unrecognized species and causes disease on beans comparable to <i>Curtobacterium flaccumfaciens</i>. Isolates from the stratosphere (strain L6-1) and agricultural millet (G77) were identified to be the same species and designated as <i>Curtobacterium aetherium</i> sp. nov. <i>C. aetherium</i> displays high levels of tolerance to desiccation and UV radiation, which are stresses that increase in intensity with altitude. Back trajectory air mass analysis implied that the phytopathogens may have had an intercontinental source, but regional origins in the continental US cannot be excluded. The environmentally robust phytopathogens we have documented in the upper atmosphere provide new perspective on the role that high-altitude transport may play in microbial dispersal, gene flow, and the epidemiology of aerially dispersed plant disease.</p><p><strong>Importance: </strong>Enormous quantities and varieties of microorganisms are continually aerosolized and transported in the atmosphere, yet there is a limited understanding of the consequences to downwind ecosystems. While studying bacteria that survive extreme conditions at altitudes up to 29 km in the atmosphere, we discovered new species that have the capacity to cause disease in agriculturally relevant bean varieties. The hardiest isolate we characterized from the stratosphere is a member of the same species as an isolate from an agricultural source, which we have designated <i>Curtobacterium aetherium</i>. <i>C. aetherium</i> is a phytopathogen capable of enduring high-altitude and long-distance atmospheric transport while also possessing the potential to opportunistically infect crops in deposition locations.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0177424"},"PeriodicalIF":3.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143763770","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":"Comparative efficacy and safety of pegylated interferon-alpha monotherapy vs combination therapies with entecavir or tenofovir in chronic hepatitis B patients.","authors":"Huiqing Liang, Xiaoting Zheng, Qianguo Mao, Jiaen Yang, Qingfa Ruan, Chuncheng Wu, Yaoyu Liu, Siyan Chen, Luyun Zhang, Manying Zhang, Hongli Zhuang, Li Lin, Shaodong Chen","doi":"10.1128/spectrum.02694-24","DOIUrl":"https://doi.org/10.1128/spectrum.02694-24","url":null,"abstract":"<p><p>Current treatments for chronic hepatitis B (CHB) virus involve nucleos(t)ide analogs and pegylated interferon-alpha (PEG-IFNα). This study compares the efficacy and safety of PEG-IFNα monotherapy with its combinations with entecavir (ETV) and tenofovir disoproxil fumarate (TDF) in managing CHB. We included 147 treatment-naïve patients divided into three groups: Group A (PEG-IFNα-2b with ETV), Group B (PEG-IFNα-2b with TDF), and Group C (PEG-IFNα-2b monotherapy). Evaluations occurred every 12 weeks up to 48 weeks. The Kaplan-Meier method showed no significant differences in cumulative HBsAg loss, but HBV DNA clearance rates were higher in the TDF group than in the ETV group (<i>P</i> = 0.01). Higher incidences of elevated alanine aminotransferase (ALT), aspartate aminotransferase, and thrombocytopenia were observed in the TDF group compared to other groups. After propensity score matching, the TDF group had a higher undetectable HBV DNA rate than the IFN group, but no significant differences in HBsAg clearance rates. Both TDF and ETV groups achieved more significant HBsAg reductions from baseline to week 48 than the IFN group (<i>P</i> < 0.05). ETV showed a lower HBeAg clearance rate (30.00% vs 87.50%, <i>P</i> < 0.05) but higher ALT normalization (76.92% vs 45.45%, <i>P</i> < 0.05). In the TDF group, patients with lower baseline HBsAg levels, high ALT levels, and lower aspartate aminotransferase-to-platelet ratio index (APRI) scores were more likely to achieve HBsAg loss. These findings suggest that TDF and ETV are effective for viral suppression, with TDF showing superior HBV DNA clearance but more adverse events.</p><p><strong>Importance: </strong>This study investigates how different treatments for chronic hepatitis B (CHB), a widespread liver infection, compare in effectiveness and safety. By evaluating the use of pegylated interferon-alpha alone and in combination with two other drugs, entecavir and tenofovir disoproxil fumarate (TDF), researchers found that TDF offers better viral suppression but also comes with more side effects. For patients receiving TDF combined with PEG-IFN therapy, low HBsAg levels, elevated alanine aminotransferase levels, and lower APRI scores were associated with a higher likelihood of achieving HBsAg loss. Consistent with previous findings, this study confirms the benefits of nucleos(t)ide analog plus PEG-IFN therapy for CHB treatment and further explores which patients are more likely to benefit from combination therapy. Furthermore, this study underscores the importance of further monitoring adverse events in patients receiving combination therapy.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0269424"},"PeriodicalIF":3.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143763992","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":"Genetic relationships of <i>Aspergillus fumigatus</i> in hospital settings during COVID-19.","authors":"Raeseok Lee, Won-Bok Kim, Sung-Yeon Cho, Dukhee Nho, Chulmin Park, Hye-Sun Chun, Jun-Pyo Myong, Dong-Gun Lee","doi":"10.1128/spectrum.01902-24","DOIUrl":"https://doi.org/10.1128/spectrum.01902-24","url":null,"abstract":"<p><p>The transmission pathways and risks of COVID-19-associated pulmonary aspergillosis (CAPA) remain unclear. This study investigated the genetic relationships of <i>Aspergillus fumigatus</i> isolates from patients with and without COVID-19 and environmental air samples to suggest possible transmission patterns. We conducted a prospective study from March 2020 to December 2022, collecting clinical and environmental isolates from a tertiary hospital. Isolates from patients with and without COVID-19 were compared with those from air samples at four hospital locations. The genetic analysis included internal transcribed spacer and <i>β-tubulin A</i> sequencing, with azole resistance assessed via <i>cyp51A</i> gene analysis. Multiple locus variable-number tandem repeat analysis was performed to elucidate genetic relationships. A total of 155 isolates (19 from COVID-19 patients, 104 from non-COVID-19 patients, and 32 from environmental samples) were identified and genotyped, revealing 131 sequence types (Simpson Diversity Index 0.9972). Four CAPA clinical strains genetically related to environmental strains were isolated from the COVID-19 intensive care unit (ICU), while two CAPA clinical strains sharing multiple locus variable-number tandem repeat sequence types and azole-resistant mutations were isolated in the same COVID-19 ICU 4 months apart. All but one of these strains were isolated from patients requiring mechanical ventilation. The observed genetic similarities between strains from critically ill patients with COVID-19 and those from the environment, as well as within the same ICU, raise the possibility of nosocomial acquisition via contaminated air or environmental sources. These findings highlight the risks of CAPA associated with negative pressure rooms and the need for enhanced environmental infection control measures.IMPORTANCEThis study reveals genetic links between <i>Aspergillus fumigatus</i> in patients with COVID-19 and environmental sources, suggesting nosocomial transmission and urging a reevaluation of universal negative pressure isolation practices in hospitals, especially for critically ill patients.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0190224"},"PeriodicalIF":3.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143764303","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":"A TaqMan-MGB real-time PCR for discriminating between MS-H-live vaccine and field <i>Mycoplasma synoviae</i> strains.","authors":"Ziqing Liu, Shouchang Zhou, Chenchen Meng, Doudou Ren, Weizhen Xiong, Guanhui Liu, Jinpeng Xu","doi":"10.1128/spectrum.03591-23","DOIUrl":"https://doi.org/10.1128/spectrum.03591-23","url":null,"abstract":"<p><p><i>Mycoplasma synoviae</i> (MS) is an important pathogen in the poultry industry and has caused significant economic losses. Worldwide, the use of live attenuated vaccine for the MS-H strain has increased to prevent MS infection. However, there is no test available to discriminate the MS-H vaccine strains from the MS strains that are causing field infection. In this study, a TaqMan-MGB real-time PCR method (qPCR) was established, validated, and evaluated to discriminate between MS-H-live vaccine and field strains based on nucleotide differences in the <i>hlyC</i> gene. The validation was performed for sensitivity and reproducibility by constructing recombinant plasmids. The limits of detection were 1.07 × 10¹ copies/µL for the MS-H and 1.95 × 10¹ copies/µL for field strains, respectively. The intra- and inter-assay results were less than 2.5% based on the reproducibility test. No cross-amplification signals from other common chicken pathogens were detected. Thus, our data indicated that this qPCR is sensitive, specific, and reproducible. In addition, 709 chicken clinical samples were used to evaluate this qPCR test. The results showed that positive signals could be detected from the chicken choanal cleft swabs and are 100% in concordance with the PCR sequencing method. To the best of our knowledge, we found for the first time that both L- and C-type field MS were present in flocks immunized against the MS-H vaccine strain during the validation process. In addition, this is the first report of a field strain of C-type in China.IMPORTANCE<i>Mycoplasma synoviae</i> (MS) is an important pathogen in the poultry industry and has caused significant economic losses. Worldwide, an increasing number of farms are using the live attenuated vaccine MS-H strain to prevent MS infections. In order to monitor vaccinated and naturally infected flocks and to continue the MS control and eradication program, a differentiation of infected from vaccinated animals (DIVA) test for MS is urgently needed. We developed a TaqMan-MGB real-time qPCR (qPCR) method with a pair of primers and two competitive TaqMan-MGB probes. We performed an evaluation that can discriminate between the MS-H-live vaccine and field MS strains based on nucleotide differences in the <i>hlyC</i> gene. It has great sensitivity and reproducibility, and greater specificity than other methods which were established by SNP sites of the <i>obg</i> gene and <i>oppF</i> gene.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0359123"},"PeriodicalIF":3.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143764034","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":"Synergistic impact of macrolide resistance and H3N2 infection on <i>M. pneumoniae</i> outbreak in children.","authors":"Jiali Chen, Yingdan Wang, Juan Cheng, Yunping Ma, Xin Zhang, Xuezhou Bai, Palizhati Rehati, Huashun Cui, Fan Wu, Qiuhui Pan, Jinghe Huang","doi":"10.1128/spectrum.01844-24","DOIUrl":"10.1128/spectrum.01844-24","url":null,"abstract":"<p><p>In November 2023, there was a substantial increase in the incidence of <i>Mycoplasma pneumoniae</i> infections in China following waves of SARS-CoV-2 Omicron variant and influenza outbreaks. This study aimed to elucidate the epidemiological features and clinical implications of <i>M. pneumoniae</i> infections in children and explore the potential influence of SARS-CoV-2 Omicron variants and influenza A infections on the <i>M. pneumoniae</i> outbreak. Among 38,668 children with lower respiratory tract infections from January to December 2023, 11,919 tested positive for <i>M. pneumoniae</i>, predominantly between October and December. The majority of the children with <i>M. pneumoniae</i> were aged 5-10 years, with type 1 strains and macrolide-resistant <i>M. pneumoniae</i> strains having the highest prevalence rates. Statistical analysis revealed elevated C-reactive protein, neutrophil, and monocyte levels and decreased lymphocyte, basophil, and eosinophil counts in <i>M. pneumoniae</i>-positive children. <i>M. pneumoniae</i>-positive children also presented significantly increased neutralizing antibody levels against preceding influenza A (H3N2) but not against SARS-CoV-2 Omicron variants. A parallel trend was observed between <i>M. pneumoniae</i> and H3N2 prevalence from June to December 2023. The emergence of macrolide-resistant strains and prior influenza A (H3N2) epidemics notably contributed to the <i>M. pneumoniae</i> outbreak. These findings suggested that H3N2 infection facilitates <i>M. pneumoniae</i> infection through various mechanisms. This study underscores the complex interactions between respiratory pathogens and highlights the need for comprehensive surveillance and response strategies.IMPORTANCEThis study identified key factors contributing to an outbreak of <i>Mycoplasma pneumoniae</i> that affected 11,919 children. The influencing factors included a high prevalence of macrolide-resistant epidemic strains (94.2%) and significantly higher H3N2 neutralizing antibody levels (<i>P</i> < 0.0001) stimulated by the preceding H3N2 influenza epidemic. These findings highlight the complex relationship between the prevalence of <i>M. pneumoniae</i> and H3N2 infection in children, indicating that it is necessary to consider pathogen interactions in respiratory disease management by continuously monitoring respiratory pathogens. The emergence of macrolide-resistant strains in China and the previous H3N2 influenza epidemic significantly exacerbated the severity of the <i>M. pneumoniae</i> outbreak. H3N2 infection potentially amplifies Mycoplasma transmission. This study elucidates the epidemiological and clinical aspects of <i>M. pneumoniae</i> infections in children, yields insights regarding the cause of the outbreak, and provides guidance for improving respiratory infection management.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0184424"},"PeriodicalIF":3.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11960130/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143492913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperpiliation, not loss of pilus retraction, reduces <i>Pseudomonas aeruginosa</i> pathogenicity.","authors":"Sara L N Kilmury, Katherine J Graham, Ryan P Lamers, Lesley T MacNeil, Lori L Burrows","doi":"10.1128/spectrum.02558-24","DOIUrl":"10.1128/spectrum.02558-24","url":null,"abstract":"<p><p>Type IVa pili (T4aP) are important virulence factors for many bacterial pathogens. Previous studies suggested that the retraction ATPase, PilT, modulates pathogenicity due to its critical role in pilus dynamics and twitching motility. Here we use a <i>Caenorhabditis elegans</i> slow-killing model to show that hyperpiliation, not loss of pilus retraction, reduces virulence of <i>Pseudomonas aeruginosa</i> strains PAK and PA14. Hyperactivating point mutations in the <i>P. aeruginosa</i> PilSR two-component system that controls transcription of the major pilin gene, <i>pilA</i>, increased levels of surface pili to the same extent as deleting <i>pilT</i>, without impairing twitching motility. These functionally hyperpiliated PilSR mutants had significant defects in pathogenicity that were rescued by deleting <i>pilA</i> or through disruption of hyperpiliation via deletion of the type III secretion system needle-length regulator, PscP. Hyperpiliated <i>pilT</i> deletion or <i>pilO</i> point mutants showed similar PilA-dependent impairments in virulence, validating the phenotype. Together, our data support a model where a surfeit of pili reduces virulence, potentially through the prevention of effective engagement of contact-dependent virulence factors. These findings suggest that the role of T4aP retraction in virulence should be revised.IMPORTANCE<i>Pseudomonas aeruginosa</i> is a major contributor to hospital-acquired infections and particularly problematic due to its intrinsic resistance to many front-line antibiotics. Strategies to combat this and other important pathogens include the development of anti-virulence therapeutics. We show that the pathogenicity of <i>P. aeruginosa</i> is impaired when the amount of T4aP expressed on the cell surface increases, independent of the bacteria's ability to twitch. We propose that having excess T4aP on the cell surface may physically interfere with productive engagement of the contact-dependent type III secretion toxin delivery system. A better understanding of how T4aP modulate interaction of bacteria with target cells will improve the design of therapeutics targeting components involved in the regulation of T4aP expression and function to reduce the clinical burden of <i>P. aeruginosa</i> and other T4aP-expressing bacteria.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0255824"},"PeriodicalIF":3.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11960060/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143492956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of bedaquiline heteroresistance among <i>Mycobacterium tuberculosis</i> isolates from Pakistan.","authors":"Faiqa Rashid, Shaukat Iqbal, Sabira Tahseen, Yanlin Zhao","doi":"10.1128/spectrum.02181-24","DOIUrl":"10.1128/spectrum.02181-24","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Bedaquiline is a key drug recommended by the WHO for the treatment of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant (XDR) TB, and its use could potentially shorten treatment duration with improved outcomes. However, resistance against this drug has increased, resulting in serious concerns. Heteroresistance is among the important obstacles to complicate the detection and treatment of MTB drug resistance. We investigated the presence of bedaquiline heteroresistant MTB isolates from Pakistan to highlight their relevance to bedaquiline resistance. Whole genome sequencing of 50 phenotypically bedaquline-resistant and 50 bedaquiline-sensitive isolates revealed 29% bedaquiline heteroresistance in our study. No significant association of patient variables (age, gender, region and history of anti-tuberculosis treatment [ATT]) was found, while drug resistance pattern among MDR + bedaquiline and XDR patterns (OR, 0.53 [0.01-0.26]; &lt;i&gt;P&lt;/i&gt; ≤ 0.001 and OR, 0.09 [0.19-0.50]; &lt;i&gt;P&lt;/i&gt; = 0.006) were significantly different to bedaquiline heteroresistance. Higher proportion of bedaquiline heteroresistant cases with no history of bedaquiline containing treatment was found. Most bedaquiline heteroresistant strains (&lt;i&gt;n&lt;/i&gt; = 19) were from lineage 3, none of the strain bear mixed lineage, with &lt;i&gt;Rv0678&lt;/i&gt; mutations (95%) being the most prevalent genetic marker. We identified both new mutations (n = 17) and reported mutations (n = 21) that contribute to bedaquiline heteroresistance.The strains with missense variants had the highest percentage of heteroresistance (56%). Bedaquiline heteroresistance is an important indicator of emerging bedaquiline resistance, predominantly observed in previously treated cases without mixed infections, suggesting a higher likelihood of acquired resistance. Our findings accentuate the complexity of bedaquiline heteroresistance and the need for better diagnostic and appropriate therapeutic treatment approaches for drug-resistant TB with bedaquiline-containing regimens.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Importance: &lt;/strong&gt;This research is decisive as it investigates bedaquiline heteroresistance in &lt;i&gt;Mycobacterium tuberculosis&lt;/i&gt; (MTB) isolates from Pakistan, the sixth highest burden country for drug-resistant tuberculosis (DRTB). Bedaquiline is a key drug in the treatment of MDR/XDR-TB, and the emergence of resistance to this drug threatens global efforts to control tuberculosis. Heteroresistance, where drug-susceptible and drug-resistant strains coexist, complicates detection and treatment, potentially leading to treatment failure. By focusing on MTB isolates from Pakistan, this study addresses a critical gap in understanding the prevalence and genetic mechanisms of bedaquiline resistance in a high-burden region. The use of whole genome sequencing (WGS) adds a cutting-edge approach to identifying mutations associated with resistance, offering valuable insights that could inform more effective treatment strategies and","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0218124"},"PeriodicalIF":3.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11960095/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143483360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}