Infection and Immunity最新文献

{"title":"Infectivity of a pathogenicity-attenuated <i>Chlamydia muridarum</i> mutant in the genital tract.","authors":"Caiting Li, Zhaoyang Liu, Yaoqin Hua, Chunguang Ma, Guangming Zhong","doi":"10.1128/iai.00588-24","DOIUrl":"10.1128/iai.00588-24","url":null,"abstract":"<p><p>A <i>Chlamydia muridarum</i> mutant designated as intrOv was evaluated as an <i>intr</i>acellular <i>o</i>ral vaccine <i>v</i>ector because it can induce protection in the genital tract following oral inoculation but does not elicit genital pathology following intravaginal infection. However, the mechanism of intrOv's attenuation is unclear. Here, we report that few live organisms were recovered from vaginal swabs during the early stage of intrOv intravaginal infection in mice. At a low inoculating dose, an isogenic wild-type control strain established a productive infection, while intrOv failed to do so. Although a higher inoculating dose allowed intrOv and its control to productively infect mice, fewer live intrOv than the control organisms were recovered from the lower genital tract tissues on day 3 post-infection. By day 7, animals infected with intrOv or the control shed similar numbers of live organisms, suggesting that intrOv's deficiency on day 3 was transient. Consistently, intrOv reduced invasion of epithelial cells but maintained as robust intracellular replication as its control. Our results correlate intrOv's delay in infecting the lower genital tissues and reduction in invading epithelial cells with its attenuation in genital pathogenicity, laying the foundation for further revealing the mechanisms of intrOv's attenuation in pathogenicity during genital tract infection.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0058824"},"PeriodicalIF":2.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12150688/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144127541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Colonization dynamics of <i>Streptococcus pneumoniae</i> are determined by polymorphisms in the BlpAB transporter.","authors":"Surya D Aggarwal, Jacqueline Toussaint, John A Lees, Jeffrey N Weiser","doi":"10.1128/iai.00061-25","DOIUrl":"10.1128/iai.00061-25","url":null,"abstract":"<p><p>Colonization of the human airways, the first step in the pathogenesis of <i>Streptococcus pneumoniae</i> (<i>Spn</i>), is the determining factor in the ecological spread of the bacterium. Since co-colonization by multiple strains is common, within-host bacterial competition contributes to the success of <i>Spn</i> strains. Competition both between and within strains is mediated by bacteriocin gene clusters, notably the quorum sensing-regulated bacteriocin-like peptide (<i>blp</i>) locus. A key component of this system is the BlpAB transporter that exports pheromones and bacteriocins expressed by the <i>blp</i> locus. However, ~75% of <i>Spn</i> strains lack a functional BlpAB transporter and instead rely on the paralogous ComAB transporter for this export, raising questions about the evolutionary persistence of BlpAB(+) strains. Using molecular barcoding, we demonstrate that BlpAB(+) and BlpAB(-) strains show major differences in population dynamics during colonization modeled in mice. The BlpAB(+) strains exhibit slower loss of clonal diversity as a consequence of intrastrain competition relative to their isogenic BlpAB(-). The contribution of a functional BlpAB transporter was then examined in an association study of >2,000 human carriage isolates from a highly colonized population. The median carriage duration was ~177 days longer for BlpAB(+) relative to BlpAB(-) strains. This increased duration of natural carriage correlates with a competitive advantage for BlpAB(+) strains when tested in the murine model. Thus, our work provides insight into how differences in the population dynamics of <i>Spn</i> mediated by bacterial competition impact host colonization.IMPORTANCE<i>Spn</i> is a frequent colonizer of the human upper respiratory tract. Success during colonization is dictated by the arsenal of weapons these bacteria possess, which provides them with an advantage over their competitors. A key example includes the <i>blp</i> bacteriocins that are exported by the cell through both BlpAB and ComAB transporters. While most <i>Spn</i> strains lack a functional BlpAB, a subset of the strains retains it. Given this redundancy in export systems, our study questioned the evolutionary advantage of retaining BlpAB. Herein, we show that a functional BlpAB transporter causes a slower loss of clonal diversity <i>in vivo</i>. This correlates with longer <i>Spn</i> carriage duration in the human population and a competitive advantage during experimental co-colonization. Our work highlights the reasons behind the persistence of <i>Spn</i> with a functional BlpAB. These findings reveal how genetic variability in the <i>blp</i> locus shapes <i>Spn</i> colonization and evolutionary success.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0006125"},"PeriodicalIF":2.8,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12150690/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144093496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phosphatidylserine-binding receptor, CD300f, on macrophages mediates host invasion of pathogenic and non-pathogenic rickettsiae.","authors":"Oliver H Voss, Imran Moin, Hodalis Gaytan, Mohammad Sadik, Saif Ullah, M Sayeedur Rahman","doi":"10.1128/iai.00059-25","DOIUrl":"10.1128/iai.00059-25","url":null,"abstract":"<p><p>Some arthropod-borne obligate intracellular rickettsiae are among the most virulent human pathogens. <i>Rickettsia</i> species modulate immune (e.g., macrophages; MΦ) and non-immune cell (e.g., endothelial cells) responses to create a habitable environment for host colonization. MΦ play a crucial role in either terminating an infection at an early stage or succumbing to bacterial replication and colonization. However, our understanding of how <i>Rickettsia</i> species invade host cells, including MΦ, remains poorly defined. In this study, we describe a mechanism of host invasion by <i>Rickettsia</i> species, involving rickettsial phosphatidylserine (PS), as a ligand, and the CD300f receptor on MΦ. Our data reveal that engulfment of both pathogenic <i>Rickettsia typhi</i> (the etiologic agent of murine typhus) and <i>Rickettsia rickettsii</i> (the etiologic agent of Rocky Mountain spotted fever) species, as well as the non-pathogenic <i>Rickettsia montanensis</i>, is significantly reduced in bone marrow-derived macrophages (BMDMΦ) from CD300f^-/- mice, as compared to that of wild-type (WT) animals. Furthermore, our mechanistic analysis suggests bacterial PS as the potential source for the CD300f-mediated rickettsiae engulfment by MΦ. <i>In vivo</i> infection studies using WT and CD300f^-/- C57BL/6J mice show that CD300f^-/- animals are protected against <i>R. typhi</i>- or <i>R. rickettsii</i>-induced fatal rickettsiosis, which corroborates with the level of the bacterial burden detected in the spleens of the mice. Adoptive transfer studies reveal that CD300f-expressing MΦ are important mediators to control rickettsiosis <i>in vivo</i>. Collectively, our findings describe a previously unappreciated role for the efferocytic receptor, CD300f, to facilitate engulfment of rickettsiae within the host.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0005925"},"PeriodicalIF":2.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12150758/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143991854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Xenopus laevis</i> as an infection model for human pathogenic bacteria.","authors":"Ayano Kuriu, Kazuya Ishikawa, Kohsuke Tsuchiya, Kazuyuki Furuta, Chikara Kaito","doi":"10.1128/iai.00126-25","DOIUrl":"10.1128/iai.00126-25","url":null,"abstract":"<p><p>Animal infection models are essential for understanding bacterial pathogenicity and corresponding host immune responses. In this study, we investigated whether juvenile <i>Xenopus laevis</i> could be used as an infection model for human pathogenic bacteria. <i>Xenopus</i> frogs succumbed to intraperitoneal injection containing the human pathogenic bacteria <i>Staphylococcus aureus</i>, <i>Pseudomonas aeruginosa</i>, and <i>Listeria monocytogenes</i>. In contrast, non-pathogenic bacteria <i>Bacillus subtilis</i> and <i>Escherichia coli</i> did not induce mortality in <i>Xenopus</i> frogs. The administration of appropriate antibiotics suppressed mortality caused by <i>S. aureus</i> and <i>P. aeruginosa</i>. Strains lacking the <i>agr</i> locus, <i>cvfA</i> (<i>rny</i>) gene, or hemolysin genes in <i>S. aureus</i>, LIPI-1-deleted mutant of <i>L. monocytogenes</i>, which attenuate virulence within mammals, exhibited reduced virulence in <i>Xenopus</i> frogs compared with their respective wild-type counterparts. Bacterial distribution analysis revealed that <i>S. aureus</i> persisted in the blood, liver, heart, and muscles of <i>Xenopus</i> frogs until death. These results suggested that intraperitoneal injection of human pathogenic bacteria induces sepsis-like symptoms in <i>Xenopus</i> frogs, supporting their use as a valuable animal model for evaluating antimicrobial efficacy and identifying virulence genes in various human pathogenic bacteria.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0012625"},"PeriodicalIF":2.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12150759/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143965149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Immunogenicity and preclinical efficacy characterization of ShecVax, a combined vaccine against <i>Shigella</i> and enterotoxigenic <i>Escherichia coli</i>.","authors":"Siqi Li, Ipshita Upadhyay, Hyesuk Seo, Sai S R Vakamalla, Aashwina Madhwal, David A Sack, Weiping Zhang","doi":"10.1128/iai.00004-25","DOIUrl":"10.1128/iai.00004-25","url":null,"abstract":"<p><p>No licensed vaccines are available for the largely antibiotic-resistant <i>Shigella</i> or enterotoxigenic <i>Escherichia coli</i> (ETEC), the two most common bacteria causing children's diarrhea and travelers' diarrhea. Virulence heterogeneity is a key obstacle to developing vaccines against <i>Shigella</i> or ETEC. By applying a multiepitope fusion antigen (MEFA) vaccinology platform, we recently constructed epitope- and structure-based polyvalent proteins to induce cross-protective antibodies against heterogeneous <i>Shigella</i> or ETEC strains. In this study, we combined a polyvalent <i>Shigella</i> protein with two polyvalent ETEC proteins, examined antigen compatibility and broad immunogenicity, and evaluated the potential of developing a combined vaccine against the two groups of bacteria. Data showed that mice intramuscularly immunized with the combined vaccine candidate (ShecVax) developed antibodies to all the following target virulence factors: <i>Shigella</i> IpaB, IpaD, VirG, GuaB, StxA, Stx2A, and StxB, and ETEC STa, LT, CFA/I, CS1, CS2, CS3, CS4, CS5, and CS6. ShecVax-induced antibodies significantly inhibited the invasion of all <i>Shigella</i> species and important serotypes, prevented the adherence of all important ETEC pathotypes, and neutralized the enterotoxicity of ETEC toxins STa and LT. Moreover, ShecVax prevented mice from lethal pulmonary infection with <i>Shigella sonnei</i> or <i>S. flexneri</i> 2a, significantly reduced ETEC bacterial colonization in rabbit small intestines, and passively protected newborn pigs against ETEC toxin-mediated clinical diarrhea. These results indicated that ShecVax is broadly immunogenic and cross-protective against <i>Shigella</i> and ETEC, suggesting ShecVax can be a <i>Shigella</i>/ETEC combined vaccine against children's and travelers' diarrhea, and the MEFA platform can be generally applied for vaccine development against heterogeneous pathogens or different diseases.IMPORTANCEThere are no effective countermeasures against <i>Shigella</i> and enterotoxigenic <i>E. coli</i> (ETEC), two antibiotic-resistant groups of bacteria and the leading causes of diarrhea in children in developing countries (children's diarrhea) and international travelers (travelers' diarrhea). Vaccines are a more practical approach to protect against infectious diseases, including diarrhea caused by <i>Shigella</i> or ETEC. A combined vaccine cross-protective against <i>Shigella</i> and ETEC can save hundreds of thousands of lives and prevent hundreds of millions of diarrhea cases yearly; it can also reduce antibiotic prescription and decrease antibiotic resistance, thus significantly improving global health. In addition, we may apply the MEFA platform to develop combined vaccines against heterogeneous pathogens or different diseases to accommodate an increasingly crowded expanded program on immunization (EPI).</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0000425"},"PeriodicalIF":2.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12150686/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144020295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transdifferentiation of neutrophils facilitates the establishment of infection by <i>Leishmania donovani</i> parasites.","authors":"Madhurima Roy, Aniruddha Bagchi, Chaitali Karmakar, Mitali Chatterjee","doi":"10.1128/iai.00409-24","DOIUrl":"10.1128/iai.00409-24","url":null,"abstract":"<p><p>Neutrophil transdifferentiation involves the acquisition of dendritic cell-like properties, challenging the traditional view of neutrophils being solely phagocytes. The presence of transdifferentiated neutrophils is established in Visceral Leishmaniasis, but not in its dermal sequel, Post Kala-azar Dermal Leishmaniasis. Accordingly, this study investigated the altered functionalities of neutrophils focusing on the acquisition of dendritic cell-like properties and its impact on infection establishment. In PKDL cases, immunophenotyping of neutrophil-dendritic cells (N-DC hybrids) was performed using flow cytometry, along with studying the status of N-DC hybrid inducing cytokines (TNF-α, IFN-γ) and growth factor (GM-CSF). <i>Ex vivo</i> infection of neutrophils with <i>L. donovani</i> was monitored by droplet digital PCR, employing <i>A2</i>; additionally, their frequency of transdifferentiation, oxidative and phagocytic status, as well as apoptosis potential were quantified by flow cytometry. Compared with healthy controls, neutrophils from PKDL cases demonstrated a significant upregulation of CD83 positivity, but the frequency of co-stimulation (HLA-DR, CD80/86) was unaltered. PKDL cases demonstrated raised levels of TNF-α and IFN-γ, but GM-CSF remained unchanged. Following <i>ex vivo</i> infection of neutrophils, infection was evident at 2 h and was accompanied by CD83 positivity. Furthermore, the CD66b⁺/CD83 vis<i>-à-vis</i> CD66b⁺/CD83^- subset exhibited heightened generation of reactive oxygen species (ROS), enhanced phagocytosis, and increased apoptosis. Taken together, neutrophils from PKDL cases demonstrated transdifferentiation with the absence of antigen-presenting function. Virulent <i>Leishmania</i> induced transdifferentiation in neutrophils, altering their functionalities and facilitating parasite uptake, along with heightened generation of intra-neutrophilic ROS and enhanced apoptosis, which possibly facilitated their engulfment by macrophages, thereby bolstering the \"Trojan horse\" mechanism of parasite transfer.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0040924"},"PeriodicalIF":2.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12150689/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143963374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence for a model of conformational change by the <i>Plasmodium falciparum</i> circumsporozoite protein during sporozoite development in the mosquito host through the use of camelid single-domain antibodies.","authors":"Rob Geens, Line De Vocht, Manuela C Aguirre-Botero, Cécile Vincke, Ema Romão, Stefan Magez, Serge Muyldermans, Rogerio Amino, Yann G-J Sterckx","doi":"10.1128/iai.00081-25","DOIUrl":"10.1128/iai.00081-25","url":null,"abstract":"<p><p><i>Plasmodium</i> sporozoites (SPZs) are formed in the <i>Anopheles</i> mosquito midgut from where they travel to the salivary glands and subsequently to the mammalian liver after deposition into the skin. The SPZ's main surface antigen, the circumsporozoite protein (CSP), plays a pivotal role in SPZ biology and constitutes the immunodominant target for host antibodies. In this study, we raised single-domain antibodies (sdAbs) against CSP from <i>P. falciparum</i> (PfCSP) by immunizing two alpacas with recombinant versions of the antigen. We found that all identified sdAbs specifically target PfCSP's globular [Formula: see text]TSR domain without cross-reacting with <i>P. berghei</i> CSP. Further characterization revealed that most sdAbs recognize native PfCSP on the SPZ surface, although they do not have any inhibitory effect on hepatocyte binding and invasion. Structural studies showed that all binders target the previously identified [Formula: see text]-epitope, confirming the non-protective nature of this epitope. Comparison of sdAb binding to midgut and salivary gland SPZs revealed a shift in the exposure and accessibility of the [Formula: see text]-epitope. Hence, our findings provide further evidence that CSP undergoes structural changes during SPZ development in the mosquito host.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0008125"},"PeriodicalIF":2.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12150756/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144013124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights on the regulation and function of the CRISPR/Cas transposition system located in the pathogenicity island VpaI-7 from <i>Vibrio parahaemolyticus</i> RIMD2210633.","authors":"Jesús E Alejandre-Sixtos, Kebia Aguirre-Martínez, Jessica Cruz-López, Aliandi Mares-Rivera, Samanda M Álvarez-Martínez, David Zamorano-Sánchez","doi":"10.1128/iai.00169-25","DOIUrl":"10.1128/iai.00169-25","url":null,"abstract":"<p><p>CRISPR/Cas-mediated transposition is a recently recognized strategy for horizontal gene transfer in a variety of bacterial species. However, our understanding of the factors that control their function in their natural hosts is still limited. In this work, we report our initial genetic characterization of the elements associated with the CRISPR/Cas-transposition machinery (CASTm) from <i>Vibrio parahaemolyticus</i> (<i>Vpa</i>CASTm), which are encoded within the pathogenicity island VpaI-7. Our results revealed that the components of the <i>Vpa</i>CASTm and their associated CRISPR arrays (<i>Vpa</i>CAST system) are transcriptionally active in their native genetic context. Furthermore, we were able to detect the presence of polycistrons and several internal promoters within the loci that compose the <i>Vpa</i>CAST system. Our results also suggest that the activity of the promoter of the atypical CRISPR array is not repressed by the baseline activity of its known regulator VPA1391 in <i>V. parahaemolyticus</i>. In addition, we found that the activity of the promoter of <i>tniQ</i> was modulated by a regulatory cascade involving ToxR, LeuO, and H-NS. Since it was previously reported that the activity of the <i>Vpa</i>CAST system was less efficient than that of the <i>Vch</i>CAST system at promoting transposition of a miniaturized CRISPR-associated transposon (mini-CAST) in <i>Escherichia coli</i>, we analyzed if the transposition efficiency mediated by the <i>Vpa</i>CAST system could be enhanced inside its natural host <i>V. parahaemolyticus</i>. We provide evidence that this might be the case, suggesting that there could be host induction factors in <i>V. parahaemolyticus</i> that could enable more efficient transposition of CASTs.IMPORTANCEMobile genetic elements such as transposons play important roles in the evolutionary trajectories of bacterial genomes. The success of transposon dissemination depends on their ability to carry selectable markers that improve the fitness of the host cell or loci with addictive traits such as the toxin-antitoxin systems. Here we aimed to characterize a transposon from <i>Vibrio parahaemolyticus</i> that carries and could disseminate multiple virulence factors. This transposon belongs to a recently discovered family of transposons whose transposition is guided by crRNA. We showed that the transposition machinery of this transposon is transcribed in <i>V. parahaemolyticus</i> and that there are likely host-associated factors that favor transposition in the natural host <i>V. parahaemolyticus</i> over transposition in <i>Escherichia coli</i>.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0016925"},"PeriodicalIF":2.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12150760/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144014869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Commensal resilience: ancient ecological lessons for the modern microbiota.","authors":"Abigail E Rose, Ryan T Fansler, Wenhan Zhu","doi":"10.1128/iai.00502-24","DOIUrl":"10.1128/iai.00502-24","url":null,"abstract":"<p><p>The gut microbiota constitutes a complex ecosystem essential for host health, offering metabolic support, modulating the immune system, and protecting against pathogens. However, this community faces constant destabilizing challenges, including dietary changes, antibiotics, and enteric infection. Prolonged microbiota imbalance or dysbiosis can exacerbate intestinal disease states, including inflammatory bowel disease and colorectal cancer. Understanding the mechanisms that sustain microbiota resilience in the face of these imbalances is crucial for maintaining host health and developing effective therapeutics. This review explores microbiota resilience through the lens of an ecological model, emphasizing the interplay between microbial communities and host-driven environmental controls. We highlight two critical factors shaping microbiota resilience: oxygen tension and iron availability-challenges encountered by ancient anaerobic organisms during early evolutionary history, from which the predominant members of the microbiota have descended. Disruptions in intestinal anaerobiosis during inflammation increase luminal oxygen levels, favoring pro-inflammatory facultative anaerobes and depleting obligately anaerobic commensals. Simultaneously, host nutritional immunity restricts iron availability, further challenging commensal survival. This dual environmental challenge of rising oxygen tension and reduced iron availability is a convergent outcome of a diverse array of perturbations, from pathogen invasion to antibiotic treatment. By highlighting these conserved downstream environmental challenges rather than the specific upstream perturbations, this ecological view offers a focused framework for understanding microbiota resilience. This perspective not only enhances our understanding of host-microbiota interactions but also informs therapeutic strategies to foster resilience and support host health.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0050224"},"PeriodicalIF":2.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12150765/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144093498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Augmented insights and minor adjustments to the role of adhesin proteins in <i>Acinetobacter baumannii</i> infections.","authors":"Dongmei Xiao, Huaichang Zhong, Qionghua Huang, Mei Cha","doi":"10.1128/iai.00066-25","DOIUrl":"10.1128/iai.00066-25","url":null,"abstract":"","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0006625"},"PeriodicalIF":2.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12150684/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144127538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}