Microbiology-Sgm最新文献

{"title":"Targeting <i>Mycobacterium tuberculosis</i> pH-driven adaptation.","authors":"Shelby J Dechow, Robert B Abramovitch","doi":"10.1099/mic.0.001458","DOIUrl":"10.1099/mic.0.001458","url":null,"abstract":"<p><p><i>Mycobacterium tuberculosis</i> (Mtb) senses and adapts to host environmental cues as part of its pathogenesis. One important cue sensed by Mtb is the acidic pH of its host niche - the macrophage. Acidic pH induces widespread transcriptional and metabolic remodelling in Mtb. These adaptations to acidic pH can lead Mtb to slow its growth and promote pathogenesis and antibiotic tolerance. Mutants defective in pH-dependent adaptations exhibit reduced virulence in macrophages and animal infection models, suggesting that chemically targeting these pH-dependent pathways may have therapeutic potential. In this review, we discuss mechanisms by which Mtb regulates its growth and metabolism at acidic pH. Additionally, we consider the therapeutic potential of disrupting pH-driven adaptations in Mtb and review the growing class of compounds that exhibit pH-dependent activity or target pathways important for adaptation to acidic pH.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11165653/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140877820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comment on the effectiveness of sodium hypochlorite against <i>Clostridioides difficile</i> spores.","authors":"Jennifer L Cadnum, Claire E Kaple, William A Rutala, Curtis J Donskey","doi":"10.1099/mic.0.001436","DOIUrl":"10.1099/mic.0.001436","url":null,"abstract":"","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11165594/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141072129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comments on the tolerance of <i>Clostridioides difficile</i> spores to disinfection with sodium hypochlorite disinfectant.","authors":"J W Decousser, F Barbut, R Baron, P Parneix, T Lavigne, S Romano-Bertrand, For The Scientific Committee Of The French Society For Hospital Hygiene And The National Reference Laboratory For","doi":"10.1099/mic.0.001435","DOIUrl":"10.1099/mic.0.001435","url":null,"abstract":"","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11165617/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141072135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combined effect of SAR-endolysin LysKpV475 with polymyxin B and <i>Salmonella</i> bacteriophage phSE-5.","authors":"Marco Gontijo, Mateus Pereira Teles, Hugo Martins Correia, Genesy Pérez Jorge, Isabella Carolina Rodrigues Santos Goes, Anthony Jhoao Fasabi Flores, Márcia Braz, Lucas de Moraes Ceseti, Priscila Zonzini Ramos, Ivan Rosa E Silva, Pedro Marcus Pereira Vidigal, Jörg Kobarg, Rafael Miguez Couñago, Cristina Elisa Alvarez-Martinez, Carla Pereira, Carmen S R Freire, Adelaide Almeida, Marcelo Brocchi","doi":"10.1099/mic.0.001462","DOIUrl":"10.1099/mic.0.001462","url":null,"abstract":"<p><p>Endolysins are bacteriophage (or phage)-encoded enzymes that catalyse the peptidoglycan breakdown in the bacterial cell wall. The exogenous action of recombinant phage endolysins against Gram-positive organisms has been extensively studied. However, the outer membrane acts as a physical barrier when considering the use of recombinant endolysins to combat Gram-negative bacteria. This study aimed to evaluate the antimicrobial activity of the SAR-endolysin LysKpV475 against Gram-negative bacteria as single or combined therapies, using an outer membrane permeabilizer (polymyxin B) and a phage, free or immobilized in a pullulan matrix. In the first step, the endolysin LysKpV475 in solution, alone and combined with polymyxin B, was tested <i>in vitro</i> and <i>in vivo</i> against ten Gram-negative bacteria, including highly virulent strains and multidrug-resistant isolates. In the second step, the lyophilized LysKpV475 endolysin was combined with the phage phSE-5 and investigated, free or immobilized in a pullulan matrix, against <i>Salmonella enterica</i> subsp. <i>enterica</i> serovar Typhimurium ATCC 13311. The bacteriostatic action of purified LysKpV475 varied between 8.125 μg ml^-1 against <i>Pseudomonas aeruginosa</i> ATCC 27853, 16.25 μg ml^-1 against <i>S</i>. <i>enterica</i> Typhimurium ATCC 13311, and 32.50 μg ml^-1 against <i>Klebsiella pneumoniae</i> ATCC BAA-2146 and <i>Enterobacter cloacae</i> P2224. LysKpV475 showed bactericidal activity only for <i>P. aeruginosa</i> ATCC 27853 (32.50 μg ml^-1) and <i>P. aeruginosa</i> P2307 (65.00 μg ml^-1) at the tested concentrations. The effect of the LysKpV475 combined with polymyxin B increased against <i>K. pneumoniae</i> ATCC BAA-2146 [fractional inhibitory concentration index (FICI) 0.34; a value lower than 1.0 indicates an additive/combined effect] and <i>S</i>. <i>enterica</i> Typhimurium ATCC 13311 (FICI 0.93). A synergistic effect against <i>S</i>. <i>enterica</i> Typhimurium was also observed when the lyophilized LysKpV475 at ⅔ MIC was combined with the phage phSE-5 (m.o.i. of 100). The lyophilized LysKpV475 immobilized in a pullulan matrix maintained a significant S<i>almonella</i> reduction of 2 logs after 6 h of treatment. These results demonstrate the potential of SAR-endolysins, alone or in combination with other treatments, in the free form or immobilized in solid matrices, which paves the way for their application in different areas, such as in biocontrol at the food processing stage, biosanitation of food contact surfaces and biopreservation of processed food in active food packing.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11170124/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140913205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A historical sequence deletion in a commonly used <i>Bacillus subtilis</i> chromosome integration vector generates undetected loss-of-function mutations.","authors":"K Julia Dierksheide, Gene-Wei Li","doi":"10.1099/mic.0.001455","DOIUrl":"10.1099/mic.0.001455","url":null,"abstract":"<p><p>Since the 1980s, chromosome-integration vectors have been used as a core method of engineering <i>Bacillus subtilis</i>. One of the most frequently used vector backbones contains chromosomally derived regions that direct homologous recombination into the <i>amyE</i> locus. Here, we report a gap in the homology region inherited from the original <i>amyE</i> integration vector, leading to erroneous recombination in a subset of transformants and a loss-of-function mutation in the downstream gene. Internal to the homology arm that spans the 3' portion of <i>amyE</i> and the downstream gene <i>ldh</i>, an unintentional 227 bp deletion generates two crossover events. The major event yields the intended genotype, but the minor event, occurring in ~10 % of colonies, results in a truncation of <i>ldh</i>, which encodes lactate dehydrogenase. Although both types of colonies test positive for <i>amyE</i> disruption by starch plating, the potential defect in fermentative metabolism may be left undetected and confound the results of subsequent experiments.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11084560/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140873093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Environmental and genetic influence on the rate and spectrum of spontaneous mutations in <i>Escherichia coli</i>.","authors":"Danna R Gifford, Anish Bhattacharyya, Alexandra Geim, Eleanor Marshall, Rok Krašovec, Christopher G Knight","doi":"10.1099/mic.0.001452","DOIUrl":"10.1099/mic.0.001452","url":null,"abstract":"<p><p>Spontaneous mutations are the ultimate source of novel genetic variation on which evolution operates. Although mutation rate is often discussed as a single parameter in evolution, it comprises multiple distinct types of changes at the level of DNA. Moreover, the rates of these distinct changes can be independently influenced by genomic background and environmental conditions. Using fluctuation tests, we characterized the spectrum of spontaneous mutations in <i>Escherichia coli</i> grown in low and high glucose environments. These conditions are known to affect the rate of spontaneous mutation in wild-type MG1655, but not in a Δ<i>luxS</i> deletant strain - a gene with roles in both quorum sensing and the recycling of methylation products used in <i>E. coli</i>'s DNA repair process. We find an increase in AT>GC transitions in the low glucose environment, suggesting that processes relating to the production or repair of this mutation could drive the response of overall mutation rate to glucose concentration. Interestingly, this increase in AT>GC transitions is maintained by the glucose non-responsive Δ<i>luxS</i> deletant. Instead, an elevated rate of GC>TA transversions, more common in a high glucose environment, leads to a net non-responsiveness of overall mutation rate for this strain. Our results show how relatively subtle changes, such as the concentration of a carbon substrate or loss of a regulatory gene, can substantially influence the amount and nature of genetic variation available to selection.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11084559/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140868621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploiting cooperative pathogen behaviour for enhanced antibiotic potency: A Trojan horse approach.","authors":"Alper Mutlu, Emily J Vanderpool, Kendra P Rumbaugh, Stephen P Diggle, Ashleigh S Griffin","doi":"10.1099/mic.0.001454","DOIUrl":"10.1099/mic.0.001454","url":null,"abstract":"<p><p>Antimicrobial resistance poses an escalating global threat, rendering traditional drug development approaches increasingly ineffective. Thus, novel alternatives to antibiotic-based therapies are needed. Exploiting pathogen cooperation as a strategy for combating resistant infections has been proposed but lacks experimental validation. Empirical findings demonstrate the successful invasion of cooperating populations by non-cooperating cheats, effectively reducing virulence <i>in vitro</i> and <i>in vivo</i>. The idea of harnessing cooperative behaviours for therapeutic benefit involves exploitation of the invasive capabilities of cheats to drive medically beneficial traits into infecting populations of cells. In this study, we employed <i>Pseudomonas aeruginosa</i> quorum sensing cheats to drive antibiotic sensitivity into both <i>in vitro</i> and <i>in vivo</i> resistant populations. We demonstrated the successful invasion of cheats, followed by increased antibiotic effectiveness against cheat-invaded populations, thereby establishing an experimental proof of principle for the potential application of the Trojan strategy in fighting resistant infections.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11084615/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140874938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strain background of <i>Candida albicans</i> interacts with <i>SIR2</i> to alter phenotypic switching.","authors":"Andrew L Woodruff, Judith Berman, Matthew Anderson","doi":"10.1099/mic.0.001444","DOIUrl":"10.1099/mic.0.001444","url":null,"abstract":"<p><p>The genetic background between strains of a single species and within a single strain lineage can significantly impact the expression of biological traits. This genetic variation may also reshape epigenetic mechanisms of cell identity and environmental responses that are controlled by interconnected transcriptional networks and chromatin-modifying enzymes. Histone deacetylases, including sirtuins, are critical regulators of chromatin state and have been directly implicated in governing the phenotypic transition between the 'sterile' white state and the mating-competent opaque state in <i>Candida albicans,</i> a common fungal commensal and pathogen of humans. Here, we found that a previously ambiguous role for the sirtuin <i>SIR2</i> in <i>C. albicans</i> phenotypic switching is likely linked to the genetic background of mutant strains produced in the RM lineage of SC5314. <i>SIR2</i> mutants in a specific lineage of BWP17 displayed increased frequencies of switching to the opaque state compared to the wild-type. Loss of <i>SIR2</i> in other SC5314-derived backgrounds, including newly constructed BWP17 <i>sir2</i>Δ/Δ mutants, failed to recapitulate the increased white-opaque switching frequencies observed in the original BWP17 <i>sir2</i>Δ/Δ mutant background. Whole-genome sequencing revealed the presence of multiple imbalanced chromosomes and large loss of heterozygosity tracts that likely interact with <i>SIR2</i> to increase phenotypic switching in this BWP17 <i>sir2</i>Δ/Δ mutant lineage. These genomic changes are not found in other SC5314-derived <i>sir2</i>Δ/Δ mutants that do not display increased opaque cell formation. Thus, complex karyotypes can emerge during strain construction that modify mutant phenotypes and highlight the importance of validating strain background when interpreting phenotypes.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 3","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10999749/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140040726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbial biofilms on macroalgae harbour diverse integron gene cassettes.","authors":"Stefano Freddi, Vaheesan Rajabal, Sasha G Tetu, Michael R Gillings, Anahit Penesyan","doi":"10.1099/mic.0.001446","DOIUrl":"10.1099/mic.0.001446","url":null,"abstract":"<p><p>Integrons are genetic platforms that capture, rearrange and express mobile modules called gene cassettes. The best characterized gene cassettes encode antibiotic resistance, but the function of most integron gene cassettes remains unknown. Functional predictions suggest that many gene cassettes could encode proteins that facilitate interactions with other cells and with the extracellular environment. Because cell interactions are essential for biofilm stability, we sequenced gene cassettes from biofilms growing on the surface of the marine macroalgae <i>Ulva australis</i> and <i>Sargassum linearifolium</i>. Algal samples were obtained from coastal rock platforms around Sydney, Australia, using seawater as a control. We demonstrated that integrons in microbial biofilms did not sample genes randomly from the surrounding seawater, but harboured specific functions that potentially provided an adaptive advantage to both the bacterial cells in biofilm communities and their macroalgal host. Further, integron gene cassettes had a well-defined spatial distribution, suggesting that each bacterial biofilm acquired these genetic elements via sampling from a large but localized pool of gene cassettes. These findings suggest two forms of filtering: a selective acquisition of different integron-containing bacterial species into the distinct biofilms on <i>Ulva</i> and <i>Sargassum</i> surfaces, and a selective retention of unique populations of gene cassettes at each sampling location.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 3","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10963911/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140133109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterisation of anhydro-sialic acid transporters from mucosa-associated bacteria.","authors":"Yunhan Wu, Andrew Bell, Gavin H Thomas, David N Bolam, Frank Sargent, Nathalie Juge, Tracy Palmer, Emmanuele Severi","doi":"10.1099/mic.0.001448","DOIUrl":"10.1099/mic.0.001448","url":null,"abstract":"<p><p>Sialic acid (Sia) transporters are critical to the capacity of host-associated bacteria to utilise Sia for growth and/or cell surface modification. While N-acetyl-neuraminic acid (Neu5Ac)-specific transporters have been studied extensively, little is known on transporters dedicated to anhydro-Sia forms such as 2,7-anhydro-Neu5Ac (2,7-AN) or 2,3-dehydro-2-deoxy-Neu5Ac (Neu5Ac2en). Here, we used a Sia-transport-null strain of <i>Escherichia coli</i> to investigate the function of members of anhydro-Sia transporter families previously identified by computational studies. First, we showed that the transporter NanG, from the Glycoside-Pentoside-Hexuronide:cation symporter family, is a specific 2,7-AN transporter, and identified by mutagenesis a crucial functional residue within the putative substrate-binding site. We then demonstrated that NanX transporters, of the Major Facilitator Superfamily, also only transport 2,7-AN and not Neu5Ac2en nor Neu5Ac. Finally, we provided evidence that SiaX transporters, of the Sodium-Solute Symporter superfamily, are promiscuous Neu5Ac/Neu5Ac2en transporters able to acquire either substrate equally well. The characterisation of anhydro-Sia transporters expands our current understanding of prokaryotic Sia metabolism within host-associated microbial communities.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10955332/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140133108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}