Microbiology spectrum最新文献

{"title":"Defects in anaplerotic metabolism sensitize <i>Staphylococcus aureus</i> small colony variants to bicarbonate.","authors":"Asif Iqbal, Zannatul H Tumpa, Wyatt W Wittliff, Bennett J Blank, Basel H Abuaita, William N Beavers","doi":"10.1128/spectrum.01685-25","DOIUrl":"https://doi.org/10.1128/spectrum.01685-25","url":null,"abstract":"&lt;p&gt;&lt;p&gt;&lt;i&gt;Staphylococcus aureus&lt;/i&gt; is a facultative anaerobe that can generate energy through oxidative phosphorylation or solely glycolysis, and inhibiting oxidative phosphorylation results in the formation of small colony variants (SCVs). SCVs lack a proton motive force (PMF), increasing antibiotic tolerance and contributing to persistent infection in the host. Bicarbonate is an abundant antimicrobial compound in the human host that &lt;i&gt;S. aureus&lt;/i&gt; encounters during infection. Bicarbonate alters the PMF, enhancing antibiotic susceptibility in &lt;i&gt;S. aureus&lt;/i&gt;, but its impact on &lt;i&gt;S. aureus&lt;/i&gt; SCVs remains unexplored. We report that bicarbonate inhibits the growth of &lt;i&gt;S. aureus&lt;/i&gt; SCVs at concentrations that do not affect &lt;i&gt;S. aureus&lt;/i&gt; wild type, due to defective bicarbonate anaplerotic metabolism, resulting in increased cytoplasmic pH and alkaline toxicity. Inactivation of pyruvate carboxylase (Pyc), a critical enzyme in bicarbonate anaplerotic metabolism that combines bicarbonate and pyruvate to form oxaloacetate, increases bicarbonate sensitivity in &lt;i&gt;S. aureus&lt;/i&gt;, indicating that bicarbonate anaplerotic metabolism plays a vital role in bicarbonate detoxification. While SCVs upregulate Pyc in response to bicarbonate, cellular pyruvate levels are insufficient to sustain bicarbonate anaplerotic metabolism. Exogenous pyruvate restores bicarbonate anaplerotic metabolism and lowers the cytoplasmic pH, protecting SCVs from bicarbonate toxicity. Cytoplasmic pH alterations by bicarbonate also resensitize SCVs to aminoglycosides. &lt;i&gt;S. aureus&lt;/i&gt; treated with bicarbonate is more susceptible to neutrophil killing, indicating that bicarbonate decreases the virulence of &lt;i&gt;S. aureus&lt;/i&gt;. This study identifies bicarbonate anaplerotic metabolism as a &lt;i&gt;S. aureus&lt;/i&gt; detoxification mechanism for bicarbonate toxicity and demonstrates that modulating anaplerotic metabolism may be an effective treatment for &lt;i&gt;S. aureus&lt;/i&gt; infections.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Importance: &lt;/strong&gt;&lt;i&gt;Staphylococcus aureus&lt;/i&gt; is one of the major bacterial contributors to human deaths around the world. Metabolic flexibility allows &lt;i&gt;S. aureus&lt;/i&gt; to alter energy generation and resist oxidative and antibiotic killing, facilitating persistence in the host. Bicarbonate has been used for over a century for cleaning and hygiene without completely understanding its antimicrobial properties. We report that small colony variants (SCVs) are defective for bicarbonate anaplerotic metabolism, which is required to detoxify bicarbonate. As a result, bicarbonate inhibits the growth of SCVs by alkalinizing the cytoplasm. Cytoplasmic alkalinization also resensitizes SCVs to aminoglycoside killing, implicating bicarbonate as an effective antimicrobial adjuvant for treating glycolytic &lt;i&gt;S. aureus&lt;/i&gt;. Our study defines the impacts of bicarbonate on the growth of SCVs and the metabolic pathways involved in detoxification, indicating that bicarbonate could be effective at controlling chronic &lt;i&gt;","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0168525"},"PeriodicalIF":3.8,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145075786","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":"Diagnostic accuracy of the ESAT6-CFP10 skin test for latent tuberculosis infection among jail detainees.","authors":"Xinru Fei, Shanshan Wang, Zhan Wang, Xinsong Hu, Cheng Chen, Limei Zhu, Leonardo Martinez, Peijun Tang, Qiao Liu","doi":"10.1128/spectrum.01500-25","DOIUrl":"https://doi.org/10.1128/spectrum.01500-25","url":null,"abstract":"<p><p>As an alternative to the tuberculin skin test (TST) or QuantiFERON-TB Gold In-Tube (QFT-GIT), ESAT6-CFP10 (EC) skin test is an emerging screening method; however, its value in the diagnosis of latent tuberculosis infection (LTBI) in detainees is still unclear in China. Newly admitted detainees meeting inclusion criteria were enrolled, with demographic/clinical data collected via structured questionnaires. TST, EC skin test, and QFT-GIT screenings were performed, documenting the diameter of skin indurations and/or redness at injection sites and blistering reactions at injection sites. In total, 1,038 detainees were enrolled in this study from October 2022 to October 2023 with 236 LTBI (22.7%). The positive rate of TST, EC skin test, and QFT-GIT was 18.1%, 10.6% and 11.9%. The area under the curve for EC was 0.820, indicating a strong concordance with QFT-GIT (κ = 0.673). Compared with QFT-GIT, the sensitivity of EC was 66.9%, and the specificity was 97.0%. The mean induration diameter or redness of EC was significantly larger than that of TST (<i>P</i> < 0.001). In the regression model, no history of alcohol consumption (aOR = 0.433, 95% confidence interval [CI]: 0.200, 0.938), no history of surgical trauma (aOR = 0.731, 95% CI: 0.539, 0.991), and no drug use (aOR = 0.473, 95% CI: 0.233, 0.961) was identified as a protective factor for LTBI. The EC demonstrated both high specificity and sensitivity comparable to the QFT-GIT. When screening for LTBI among jail detainees in this setting, particular attention should be given to individuals with a history of alcohol consumption, surgical trauma, and drug use.</p><p><strong>Importance: </strong>Jail detainees represent a vulnerable population with an elevated risk of tuberculosis. The EC skin test demonstrates promising potential as an alternative to traditional diagnostic methods, such as the TST and QFT-GIT assay, for LTBI screening. Targeted screening strategies can facilitate the early detection, diagnosis, and management of LTBI.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0150025"},"PeriodicalIF":3.8,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145075796","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":"Molecular insights into the persistence and co-occurrence of two different carbapenem-resistant <i>Pseudomonas aeruginosa</i> lineages within a hospital setting.","authors":"Xinran Li, Kaiying Wang, Jiali Chen, Zixuan Chen, Jinhui Li, Peng Li, Xiong Liu, Suling Liu","doi":"10.1128/spectrum.00433-25","DOIUrl":"https://doi.org/10.1128/spectrum.00433-25","url":null,"abstract":"<p><p>Carbapenem-resistant <i>Pseudomonas aeruginosa</i> (CRPA) represents a critical-priority pathogen capable of causing life-threatening, multidrug-resistant infections. We performed susceptibility testing, whole-genome sequencing, and bioinformatic analyses on 137 CRPA isolates from a Guangdong hospital. We found that the major specimen types were respiratory specimens (57/137, 41.6%) and bronchoalveolar lavage (42/137, 30.7%). All isolates were carbapenem-resistant but had low resistance to polymyxin B (0.7%, 1/137). IncP-6-positive isolates exhibited ≥2- to 32-fold higher resistance to 9/12 antibiotics (<i>P</i> < 0.05), with no difference to imipenem and meropenem. Fifty-four sequence types and 11 O-serogroups were identified, with ST1971 (6.6%) and O11 (29.9%) being predominant. Temporal and spatial patterns suggest persistent co-occurrence of clade 1 and clade 2 isolates, indicating potential nosocomial outbreak and clonal transmission.</p><p><strong>Importance: </strong>The prevalence of carbapenem-resistant <i>Pseudomonas aeruginosa</i> (CRPA) has increased rapidly in recent years, yet few genetic and epidemiological studies on CRPA isolates have been performed. We performed susceptibility testing, whole-genome sequencing, and bioinformatic analyses on hospital isolates to investigate their resistance profiles and molecular epidemiology. These findings may offer new insights for developing effective global strategies to control CRPA and reduce untreatable infections in clinical settings.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0043325"},"PeriodicalIF":3.8,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145075832","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":"Profiling bile acids in the stools of humans and animal models of cystic fibrosis.","authors":"Melissa M Carmichael, Rebecca A Valls, Shannon Soucy, Julie Sanville, Juliette Madan, Sarvesh V Surve, Mark S Sundrud, George A O'Toole","doi":"10.1128/spectrum.01451-25","DOIUrl":"10.1128/spectrum.01451-25","url":null,"abstract":"<p><p>Cystic fibrosis (CF) is associated with aberrant bile acid (BA) metabolism. As little is known about BA in children with CF (cwCF), we performed both comprehensive (<i>n</i> = 89) and focused (<i>n</i> = 21) BA profiling in stool of children with or without CF. Our results reveal select BA species and metabolites are significantly different between cwCF and nonCF controls. Focused BA profiling revealed a significant increase in total BA levels and selected changes in a subset of BA classes for cwCF. Matched bacterial metagenomic analyses showed no change in alpha-diversity between groups in this small cohort, at odds with previous studies, whereas changes in relative abundance of <i>Bacteroidetes</i> (lower in cwCF) phylum are consistent with prior reports. A trend was noted toward reduced abundance of <i>bsh</i> gene families, a key rate-limiting enzyme required for bacterial synthesis of secondary BAs, in cwCF. Observed modest changes in both BAs and microbial BA metabolism-related gene abundances may suggest a possible combination of defects in host and microbial BA metabolic pathways in cwCF. Fecal BA profiles from both ferret and mouse CF models showed significant differences from human BA profiles, and while the ferret model reproduced significant differences between CF and nonCF animals, the nonCF animals showed higher levels of BA (opposite of what is observed in humans), indicating that neither model recapitulated BA in stool in the context of CF. Together, these results provide new insights into CF-related BA dysmetabolism in cwCF and highlight limitations of CF animal models for BA functional studies.</p><p><strong>Importance: </strong>Changes in the abundance and/or composition of intestinal BAs may contribute to dysbiosis and altered gastrointestinal physiology in CF. Here, we report shifts in select fecal BA classes and species for cwCF. Matched metagenomic analysis suggests possible defects in both host intestinal BA absorption and gut microbial BA metabolism. Additional analyses of mouse and ferret CF stool for BA composition suggest great care must be taken when interpreting BA functional studies using these animal models. Together, this work lays technical and conceptual foundations for interrogating BA-microbe interactions in cwCF.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0145125"},"PeriodicalIF":3.8,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145070084","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":"Nitric oxide donor sodium nitroprusside serves as a source of iron supporting <i>Pseudomonas aeruginosa</i> growth and biofilm formation.","authors":"Xavier Bertran I Forga, Yaoqin Hong, Kathryn E Fairfull-Smith, Jilong Qin, Makrina Totsika","doi":"10.1128/spectrum.02234-25","DOIUrl":"https://doi.org/10.1128/spectrum.02234-25","url":null,"abstract":"<p><p>Biofilm dispersal agents, like nitric oxide (NO), restore antimicrobial effectiveness against biofilm infections by inducing bacteria to shift from a biofilm to a planktonic state, thereby overcoming the antimicrobial tolerance typically associated with biofilms. Sodium nitroprusside (SNP) is a widely used NO donor for investigating the molecular mechanisms underlying NO-mediated biofilm dispersal in the nosocomial pathogen <i>Pseudomonas aeruginosa</i>. However, the biofilm effects of SNP are variable depending on the <i>in vitro</i> experimental conditions, with some studies reporting enhanced growth in both planktonic and biofilm forms instead of dispersal. These discrepancies suggest that SNP affects <i>P. aeruginosa</i> biofilm-residing cells beyond the release of NO. In this study, we compared SNP with another NO donor, Spermine NONOate, to systematically contrast their effects on biofilm and planktonic cultures of <i>P. aeruginosa</i>. We found that SNP, but not Spermine NONOate, increased the biomass of <i>P. aeruginosa</i> biofilms in microplate cultures. This effect was also observed when biofilm cultures were supplemented with iron. Additionally, supplementation with SNP rescued the planktonic growth of <i>P. aeruginosa</i> in iron-depleted media similarly to FeSO₄, suggesting that SNP may serve as an iron source. Our findings indicate that the use of SNP as an NO donor in biofilm dispersal may be compromised by its role in promoting both biofilm and planktonic growth through its iron center. Our study cautions investigators using SNP for studying NO-mediated biofilm dispersal.</p><p><strong>Importance: </strong>Research into biofilm dispersal agent nitric oxide (NO) holds promise for treating biofilm-associated infections. Sodium nitroprusside (SNP), an NO donor widely used in antibiofilm research, has been shown in this study to enhance cell growth and biofilm formation in <i>Pseudomonas aeruginosa</i> by acting as a source of iron. Our results suggest that SNP functions both as an NO and an iron donor, with its iron-releasing properties playing a more dominant role in promoting biofilm growth in closed culture systems. This study underscores the dual but conflicting roles of SNP in biofilm growth, which caution its future development as an NO-based therapeutic strategy for biofilm-associated infections.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0223425"},"PeriodicalIF":3.8,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145075850","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":"Clinical carbapenem-resistant <i>Enterobacterales</i> in a University Hospital in Dakar, Senegal: genomic insights into <i>Enterobacter hormaechei</i> ST182 strains carrying <i>bla</i>_NDM-5 and <i>bla</i>_OXA-48 genes .","authors":"Komla Mawunyo Dossouvi, Bissoume Sambe Ba, Gora Lo, Fábio Parra Sellera, João Pedro Rueda Furlan, Antoine Culot, Guillaume Abriat, Adja Bousso Gueye, Awa Ba-Diallo, Assane Dieng, Fatime Poulo Ly, Abdoulaye Cissé, Serigne Mbaye Lo Ndiaye, Alioune Tine, Farba Karam, Habsa Diagne-Samb, Safietou Ngom-Cisse, Halimatou Diop-Ndiaye, Coumba Toure-Kane, Aïssatou Gaye-Diallo, Sika Dossim, Souleymane Mboup, Cheikh Saad Bouh Boye, Abdoulaye Seck, Makhtar Camara","doi":"10.1128/spectrum.00780-25","DOIUrl":"https://doi.org/10.1128/spectrum.00780-25","url":null,"abstract":"<p><p>Senegal has witnessed the emergence and spread of carbapenem-resistant <i>Enterobacterales</i> (CRE), which often cause deadly infections. Accordingly, this study aimed to determine the antimicrobial susceptibility and prevalence of carbapenemases, as well as to perform a whole-genome sequence analysis of clinical CRE isolates from a university hospital in Dakar, Senegal. MALDI-TOF MS and VITEK2 systems were used for bacterial identification and antimicrobial susceptibility testing (AST). Carbapenemase- and cephalosporinase-encoding genes were screened using simplex end-point polymerase chain reaction. Whole-genome sequencing (WGS) was performed using the Illumina MiSeq platform. The CRE isolates were resistant to almost all the 34 antimicrobials tested. Nevertheless, colistin and amikacin remained active, with susceptibility rates of 96% and 71%, respectively. Only the carbapenemase genes <i>bla</i>_OXA-48 (53.8%; 15/28) and <i>bla</i>_NDM (35.7%; 10/28) and the cephalosporinase gene <i>bla</i>_CMY-1 (25%; 7/28) were identified. In this context, two extensively drug-resistant <i>Enterobacter hormaechei</i> isolates were subjected to WGS analysis. These isolates were assigned as sequence type (ST) 182 and carried several genes related to antimicrobial resistance (AMR), metal tolerance, and virulence. An IncL/M plasmid with 61,054 bp in length was identified as carrying the <i>bla</i>_OXA-48 gene, whereas an IncFIB(pECLA)/IncFII(pECLA)/IncX3 mutireplicon plasmid with 217,745 bp in length was detected as harboring the <i>bla</i>_NDM-5 gene and other genes related to AMR and metal tolerance. Our study presents the first landscape of clinical CRE circulating in Senegal, along with additional genomic analysis of <i>E. hormaechei</i> ST182 strains, which could be useful for mitigating the burden associated with CRE in this country.IMPORTANCEThe investigation of global critical priority CRE isolates has become crucial to reduce morbidity and mortality associated with AMR. This study revealed that colistin and amikacin can be considered good alternatives for treating CRE-associated infections in Dakar. In addition, the genomic approach revealed that the CRE isolates carried both a wide resistome and virulome. Moreover, the abundance of horizontal gene transfer regions in the genomes suggests the great implications of mobile genetic elements in the spread of AMR in Dakar. Furthermore, this study reported the complete sequences of chromosomes and <i>bla</i>_OXA-48 and <i>bla</i>_NDM-5-carrying plasmids. Our findings are of great importance because complete genome sequences are still rarely characterized in the West African region. Finally, this study highlights the importance of strengthening genomic surveillance of CRE in sub-Saharan African countries to mitigate the burden associated with these pathogens.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0078025"},"PeriodicalIF":3.8,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145069934","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":"Interaction of host gene-gut microbiota in male grading of <i>Macrobrachium rosenbergii</i>.","authors":"Xiuxin Zhao, Miuying Cai, Shunkai Yin, Ziqi Zhou, Jie Yang, Yuqing Shen, Zhenglong Xia, Qiongying Tang, Guoliang Yang, Shaokui Yi, Quanxin Gao","doi":"10.1128/spectrum.01290-25","DOIUrl":"https://doi.org/10.1128/spectrum.01290-25","url":null,"abstract":"<p><p>The giant freshwater prawn (GFP; <i>Macrobrachium rosenbergii</i>), a crustacean of high nutritional and economic value, is crucial for aquaculture. During the same growth cycle, male GFPs develop into three distinct forms: small males, orange claw males, and blue claw males. These morphotypes display varying social behaviors, which severely constrain their industrial development. To address this, this study collected male GFP samples at critical developmental time points (100, 110, and 120 days post-hatching) for phenotypic trait measurement and analysis to obtain external morphological data. Through gut microbiota diversity analysis, we identified key gut bacteria (<i>Lactococcus garvieae</i> and <i>Lactobacillus taiwanensis</i>) influencing male morphotype differentiation. Transcriptomic analysis revealed host Kyoto Encyclopedia of Gene and Genome pathways and key genes (<i>Wnt-6</i>, <i>CTSB</i>, <i>CTSL</i>, <i>PPAE</i>, and <i>TP53</i>) associated with morphotype differentiation. The interactions among phenotypic traits, gut microbiota, and key genes were systematically studied through association analysis. Weighted gene co-expression network analysis was employed to construct co-expression modules, from which critical gene modules influencing phenotypic variation were identified. Through association network analysis, we established an \"<i>Achromobacter</i>-CD-TRINITY_DN93139_c0_g2 (calpain clp-1)\" interaction model. Our findings provide novel insights into the genetic enhancement of GFPs and offer guidelines for future research regarding gut symbiotic bacteria and breeding initiatives.</p><p><strong>Importance: </strong>Male <i>Macrobrachium rosenbergii</i> (giant freshwater prawn [GFP]) in the same growth cycle will develop into small males, orange claw males, and blue claw males. This individual heterogeneity in growth significantly impacts the benefits of aquaculture. However, the factors influencing the differentiation of male GFP morphotype remain unclear. This study analyzed the phenotypic data of various GFP levels, the structure of the intestinal microbiota, and the differential genes within the gonadal transcriptome at critical time points of male GFP-level type differentiation. The aim was to explore the potential role of intestinal microbiota and differential genes in this phenomenon. This study offers new insights into the research on the phenomenon of male GFP-level type differentiation.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0129025"},"PeriodicalIF":3.8,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145069999","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":"Antibacterial activity of two newly isolated <i>Bdellovibrio bacteriovorus</i> strains on <i>Salmonella enterica</i> serovars of food safety concern.","authors":"Yewande O Ajao, Lari M Hiott, Laura E Williams, Charlene R Jackson, Jonathan G Frye","doi":"10.1128/spectrum.00861-25","DOIUrl":"https://doi.org/10.1128/spectrum.00861-25","url":null,"abstract":"<p><p><i>Bdellovibrio</i> are obligate predators and have been described as living antibiotics since their predatory lifestyle enables them to kill pathogenic bacteria, making <i>Bdellovibrio</i> a promising biological control agent. <i>Bdellovibrio</i> strains were isolated from sampling sites in an urban watershed and tested for their killing activity on <i>Salmonella enterica</i> strains associated with human infections. An enrichment technique was used to isolate <i>Bdellovibrio</i> from surface water samples from local tributaries to the Oconee River, employing <i>Salmonella</i> Infantis as the prey bait. The isolated <i>Bdellovibrio</i> strains were sequenced; their prey range activity was tested against a panel of clinically significant <i>S. enterica</i> serovars, while predation efficiency was tested on <i>S</i>. Infantis. The result demonstrated the ability of two newly isolated periplasmic <i>Bdellovibrio bacteriovorus</i> strains, <i>B. bacteriovorus</i> YOA24 and <i>B. bacteriovorus</i> YOA38, to kill 11 antibiotic-resistant <i>S. enterica</i> serovars and effectively reduce <i>S</i>. Infantis populations. The strains were identified as periplasmic <i>Bdellovibrio</i> and members of <i>B. bacteriovorus</i> based on phenotypic, microscopic, and genotypic characterization. <i>B. bacteriovorus</i> YOA 24 and YOA38 demonstrated the ability to reduce <i>S</i>. Infantis by 2 logs in 24 h. The killing activity of <i>B. bacteriovorus</i> YOA24 and YOA38 indicates their potential to manage <i>Salmonella</i> outbreaks. Therefore, <i>B. bacteriovorus</i> strains YOA24 and YOA38 can be considered for development as therapeutic agents or probiotics against <i>Salmonella</i>.</p><p><strong>Importance: </strong><i>Bdellovibrio</i> is the most studied obligate predatory bacteria. It has potential for use as biological control of gram-negative bacteria in health, agriculture, and the food industry. Most basic research and applications use the type strain <i>Bdellovibrio bacteriovorus</i> HD100 or a closely related strain 109J. Screening for other <i>Bdellovibrio</i> strains and their killing activity should be explored, knowing that prey range and efficiency could differ among <i>Bdellovibrio</i> strains. This study presents two newly isolated <i>B. bacteriovorus</i> strains, YOA24 and YOA38, with lytic activity on <i>Salmonella enterica</i> serovars. <i>B. bacteriovorus</i> YOA24 and YOA38 represent a biological control agent for foodborne <i>S. enterica</i> serovars due to their killing activity on the important <i>Salmonella</i> strains tested.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0086125"},"PeriodicalIF":3.8,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145065282","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":"Performance evaluation of a commercial multiplex pathogen panel for detection of bacteria in sputum specimens from non-ICU patients with suspected lower respiratory tract infection.","authors":"Madeline Gemoules, Tristan T Timbrook, Elizabeth Neuner, Rebekah E Dumm, Tamara Krekel","doi":"10.1128/spectrum.02111-25","DOIUrl":"https://doi.org/10.1128/spectrum.02111-25","url":null,"abstract":"<p><p>Rapid diagnostic testing can improve pathogen detection and lead to targeted antibiotics. The BioFire FilmArray Pneumonia Panel (BFPP) is a multiplex PCR that has displayed strong concordance with traditional microbiologic techniques. However, most existing literature focuses on deep respiratory specimens, and there is sparse literature on performance in sputum specimens. This retrospective, single-center study included adult patients between 1 September 2022 and 31 August 2024 who had collection of a BFPP with standard of care (SOC) culture from a sputum specimen on a non-intensive care unit (ICU) floor or in the emergency department if admitted to a non-ICU floor. Out of 189 BFPPs performed on 189 sputum specimens, a total of 141 bacterial targets were detected. Between the BFPP and SOC culture, the overall positive percent agreement and negative percent agreement (NPA) were 96.3% and 54.9%, respectively. The positive predictive value (PPV) was 26.3% while the negative predictive value was 98.9%. Patients with greater than 24 h of antibiotic exposure prior to BFPP collection had a lower PPV compared to patients with less than 24 h or no exposure (13.6% vs 29.6% vs 30.4%). The lowest concordance was observed for <i>Haemophilus influenzae</i> (15.4%), <i>Moraxella catarrhalis</i> (18.2%), <i>Streptococcus pneumoniae</i> (19%), and <i>Staphylococcus aureus</i> (22.7%), several of which are fastidious in culture. BFPP showed a high NPA, with all bacterial targets having an NPA greater than 90%, except <i>H. influenzae</i> (82%). Based on these data, a negative BFPP in sputum specimens could help to rule out a bacterial pneumonia, but the benefit of a positive test remains unclear.IMPORTANCEThis study evaluates the BioFire FilmArray Pneumonia Panel (BFPP) by comparing its performance to standard of care cultures exclusively in sputum specimens from non-intensive care unit patients with suspected lower respiratory tract infection. Findings show an overall high positive percent agreement and negative predictive value but a low negative percent agreement and positive predictive value, suggesting that a negative test in sputum specimens could be beneficial when attempting to rule out a bacterial infection, but the benefit of a positive test remains unclear, particularly if common airway colonizing bacteria are detected and at low semi-quantitative thresholds. Clinical symptoms should guide test interpretation in patients with positive BFPP results but negative culture growth.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0211125"},"PeriodicalIF":3.8,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145065289","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 of dehydrogenase, hydratase, and aldolase responsible for the propionyl residue removal in degradation of cholic acid C-17 side chain in <i>Comamonas testosteroni</i> TA441.","authors":"Masae Horinouchi","doi":"10.1128/spectrum.00308-25","DOIUrl":"https://doi.org/10.1128/spectrum.00308-25","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Bacterial steroid degradation is gaining attention for its diverse roles, such as &lt;i&gt;Mycobacterium tuberculosis&lt;/i&gt;'s reliance on the degradation of the C17 side chain of cholesterol for survival in host environments. ORF40-44 of &lt;i&gt;Comamonas testosteroni&lt;/i&gt; TA441, previously characterized for its A-, B-, C-, and D-ring cleavage pathways, were hypothesized to correspond to the &lt;i&gt;igr&lt;/i&gt; operon of &lt;i&gt;M. tuberculosis&lt;/i&gt;, encoding the dehydrogenase ChsE1E2, hydratase ChsH1H2&lt;sub&gt;MaoC&lt;/sub&gt;, and aldolase Ltp2 ChsH2&lt;sub&gt;DUF35&lt;/sub&gt;, responsible for propionyl residue removal in the degradation of the cholic acid C17 side chain. However, low amino acid identity between the corresponding enzymes precluded functional assignment without experimental evidence. In this study, we generated gene-disrupted mutants of ORF40-44 and demonstrated that ORF41/ORF44, ORF40/ORF42, and ORF43 encode the dehydrogenase, hydratase, and aldolase, respectively. ORF40 encodes a bifunctional protein comprising MaoC and DUF35 domains. The MaoC domain of ORF40 and the ORF42-encoded protein form the hydratase, while the DUF35 domain is essential for aldolase activity. A mutant expressing ORF40&lt;sub&gt;MaoC&lt;/sub&gt; and ORF40&lt;sub&gt;DUF35&lt;/sub&gt; separately exhibited both hydratase and aldolase activities, suggesting these activities do not require a strictly formed complex of hydratase and aldolase. However, efficient propionyl residue removal appears to depend on the proper formation of each enzymatic complex, including ChsE1E2, ChsH1H2&lt;sub&gt;MaoC&lt;/sub&gt;, and Ltp2ChsH2&lt;sub&gt;DUF35&lt;/sub&gt;. Although (ChsE1-ChsE2)&lt;sub&gt;2&lt;/sub&gt; does not form a stable complex with (ChsH1-ChsH2&lt;sub&gt;MaoC&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;-(Ltp2-ChsH2&lt;sub&gt;DUF35&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;, some degree of interaction was suggested. AlphaFold-predicted three-dimensional structures of the TA441 enzymes and their complexes revealed striking similarities to those of &lt;i&gt;M. tuberculosis&lt;/i&gt;, despite low amino acid identities. These findings shed light on the structural and functional conservation of bacterial steroid-degrading enzymes.IMPORTANCEResearch on bacterial steroid degradation began over 50 years ago, primarily to produce substrates for steroid drugs. Recently, the role of steroid-degrading bacteria in human health has garnered increasing attention. &lt;i&gt;Comamonas testosteroni&lt;/i&gt; TA441 is a prominent model organism for studying aerobic steroid degradation, with its overall pathways for A-, B-, C-, and D-ring cleavage already elucidated. In this study, we identified the mechanism for removing the propionyl residue in the degradation of the cholic acid C17 side chain, a crucial step in degrading steroids with a C17 side chain, such as cholic acid, cholesterol, and other biologically significant compounds in animals and plants. The functions and structures of the identified enzymes show remarkable similarity to those in &lt;i&gt;Mycobacterium tuberculosis&lt;/i&gt;. These findings suggest that insights gained from TA441 could provide valuable clues for","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0030825"},"PeriodicalIF":3.8,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145065328","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}