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A considerable amount of research has focused on elucidating the mechanisms by which cytokines synthesized by cells of the innate immune system participate in the life-threatening multiple-organ failure of endotoxic shock. We show here that alphabeta T cells, which are archetypes of the adaptive cellular immune response, suppress the proinflammatory cascade triggered during the early stages of lipopolysaccharide (LPS)-induced endotoxemia. The absence of alphabeta T cells led to the fulminant death of LPS-challenged mice, coinciding with a massive release of the proinflammatory cytokines tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma and a marked reduction in the synthesis of the immunosuppressive cytokine transforming growth factor (TGF)-beta. Cytotoxic T lymphocyte antigen (CTLA)-positive alphabeta T cells emerging shortly after LPS challenge appear to control TGF-beta synthesis. The neutralization of either TGF-beta or CTLA4 resulted in similar increases in IFN-gamma and TNF-alpha serum concentrations in LPS-challenged mice. These observations suggest that suppressor alphabeta T lymphocytes protect against the proinflammatory cascade unleashed during the innate stages of endotoxemia. [ABSTRACT FROM AUTHOR]

After centuries of relative stability, the scientific publishing world has undergone tremendous disruption and change during the first decades of the 21st century. The causes for disruption can be traced to the information revolution, which brought such benefits as rapid publication, greater connectivity, and ready access to large databases, along with less desirable practices including image manipulation, plagiarism, and other ethical transgressions. The information revolution has driven the proliferation of journals, expansion of for-profit academic publishing, and empowerment of the open-access movement, each of which has exerted new financial pressures on traditional publishing models. As journals became the focal point for ethical concerns in science, they have adapted by increasing the scope of their duties, which now include archiving of data, enforcement of good practices, establishment of standards for rigor, and training the next generation of reviewers and editors. Here, we consider the seismic changes occurring in scientific publishing and place them into the context of a rapidly changing landscape of scientific and publishing norms., Competing Interests: The authors declare no conflict of interest.

Chromobacterium violaceum is a ubiquitous environmental pathogen. Despite its remarkable adaptability, little is known about the mechanisms of stress resistance in this bacterium. Here, in a screen for iron-susceptible transposon mutants, we identified a cytochrome bd that protects C. violaceum against multiple stresses. The two subunits of this cytochrome bd (CioAB) are encoded by the cioRAB operon, which also encodes a GbsR-type MarR family transcription factor (CioR). A Δ cioAB mutant strain was sensitive to iron and the iron-requiring antibiotic streptonigrin and showed a decrease in siderophore production. Growth curves and survival assays revealed that the Δ cioAB strain was also sensitive to zinc, hydrogen peroxide, nitric oxide, sulfide, and cyanide. Expression analysis showed that the promoter activity of the cioRAB operon and the transcript levels of the cioAB genes were increased in a Δ cioR mutant. CioR bound the promoter region of the cio operon in vitro , indicating that CioR is a direct repressor of its own operon. Expression of the cio operon increased at high cell density and was dependent on the quorum-sensing regulator CviR. As cyanide is also a signal for cio expression, and production of endogenous cyanide is known to be a quorum sensing-regulated trait in C. violaceum , we suggest that CioAB is a cyanide-insensitive terminal oxidase that allow respiration under cyanogenic growth conditions. Our findings indicate that the cytochrome bd CioAB protects C. violaceum against multiple stress agents that are potentially produced endogenously or during interactions with a host., Importance: The terminal oxidases of bacterial respiratory chains rely on heme-copper (heme-copper oxidases) or heme (cytochrome bd ) to catalyze reduction of molecular oxygen to water. Chromobacterium violaceum is a facultative anaerobic bacterium that uses oxygen and other electron acceptors for respiration under conditions of varying oxygen availability. The C. violaceum genome encodes multiple respiratory terminal oxidases, but their role and regulation remain unexplored. Here, we demonstrate that CioAB, the single cytochrome bd from C. violaceum , protects this bacterium against multiple stressors that are inhibitors of heme-copper oxidases, including nitric oxide, sulfide, and cyanide. CioAB also confers C. violaceum resistance to iron, zinc, and hydrogen peroxide. This cytochrome bd is encoded by the cioRAB operon, which is under direct repression by the MarR-type regulator CioR. In addition, the cioRAB operon responds to quorum sensing and to cyanide, suggesting a protective mechanism of increasing CioAB in the setting of high endogenous cyanide production.

Background: Antimicrobial resistance (AMR) is a global threat to infectious disease control, particularly among recently hospitalized children. We sought to determine the prevalence and mitigating factors of resistance in enteric Escherichia coli among children discharged from health facilities in western Kenya., Methods: Between June 2016 and November 2019, children aged 1 to 59 months were enrolled at the point of discharge from the hospital. E coli was isolated by microbiological culture from rectal swabs at baseline. β-Lactamases and macrolide resistance-conferring genes were detected by polymerase chain reaction. A modified Poisson regression model was used to assess the predictors mph (A) and CTX-M-type extended-spectrum β-lactamase (ESBL)., Results: Of the 238 children whose E coli isolates were tested, 91 (38.2%) and 109 (45.8%) had detectable CTX-M-type ESBL and mph (A) genes, respectively. Antibiotic treatment during hospitalization (adjusted prevalence ratio [aPR], 2.47; 95% CI, 1.12-5.43; P = .025), length of hospitalization (aPR, 1.42; 95% CI, 1.00-2.01; P = .052), and the practice of open defecation (aPR, 2.47; 95% CI, 1.40-4.36; P = .002) were independent predictors for CTX-M-type ESBL and mph (A) genes. Pneumococcal vaccination was associated with a 43% lower likelihood of CTX-M-type ESBL (aPR, 0.57; 95% CI, .38-.85; P = .005), while measles vaccination was associated with a 32% lower likelihood of mph (A) genes (aPR, 0.68; 95% CI, .49-.93; P = .017) in E coli isolates., Conclusions: Among children discharged from the hospital, history of vaccination, shorter hospital stay, lack of in-hospital antibiotic exposure, and improved sanitation were associated with a lower likelihood of AMR genes. To mitigate the continued spread of AMR, AMR control programs should consider strategies beyond antimicrobial stewardship, including improvements in sanitation, increased vaccine coverage, and the development of novel vaccines., Competing Interests: Potential conflicts of interest. All authors: No reported conflicts., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: Nontoxigenic Corynebacterium diphtheriae, often associated with wounds, can rarely cause infective endocarditis (IE). Five patients with C. diphtheriae IE were identified within 12 months at a Seattle-based hospital system. We reviewed prior C. diphtheriae-positive cultures to determine if detections had increased over time and evaluated epidemiologic trends., Methods: We conducted a formal electronic health record search to identify all patients aged ≥18 years with C. diphtheriae detected in a clinical specimen (ie, wound, blood, sputum) between 1 September 2020 and 1 April 2023. We collected patient demographics, housing status, comorbidities, substance-use history, and level of medical care required at detection. We extracted laboratory data on susceptibilities of C. diphtheriae isolates and on other pathogens detected at the time of C. diphtheriae identification., Results: Between 1 September 2020 and 1 April 2023, 44 patients (median age, 44 years) had a C. diphtheriae-positive clinical culture, with most detections occurring after March 2022. Patients were predominantly male (75%), White (66%), unstably housed (77%), and had a lifetime history of injecting drugs (75%). Most C. diphtheriae-positive cultures were polymicrobial, including wound cultures from 36 (82%) patients and blood cultures from 6 (14%) patients, not mutually exclusive. Thirty-four patients (77%), including all 5 patients with C. diphtheriae IE, required hospital admission for C. diphtheriae or a related condition. Of the 5 patients with IE, 3 died of IE and 1 from COVID-19., Conclusions: Findings suggest a high-morbidity outbreak disproportionately affecting patients who use substances and are unstably housed., Competing Interests: Potential conflicts of interest. E. N. K. and E. J. C. received Infectious Diseases Society of America (IDSA) travel grants to attend ID Week. T. F. received a travel grant to attend the Conference on Retroviruses and Opportunistic Infections (CROI). H. N. K. is funded by the National Institute for Allergy and Infectious Diseases and Gilead, with funds paid directly to the institution, unrelated to this work. P. S. P. and E. J. C. received honoraria for teaching CME courses through Providence Health System, unrelated to this work. All other authors report no potential conflicts. All authors have completed the ICMJE conflict of interest forms. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Despite modern antiseptic techniques, surgical site infection (SSI) remains a leading complication of surgery. However, the origins of SSI and the high rates of antimicrobial resistance observed in these infections are poorly understood. Using instrumented spine surgery as a model of clean (class I) skin incision, we prospectively sampled preoperative microbiomes and postoperative SSI isolates in a cohort of 204 patients. Combining multiple forms of genomic analysis, we correlated the identity, anatomic distribution, and antimicrobial resistance profiles of SSI pathogens with those of preoperative strains obtained from the patient skin microbiome. We found that 86% of SSIs, comprising a broad range of bacterial species, originated endogenously from preoperative strains, with no evidence of common source infection among a superset of 1610 patients. Most SSI isolates (59%) were resistant to the prophylactic antibiotic administered during surgery, and their resistance phenotypes correlated with the patient's preoperative resistome ( P = 0.0002). These findings indicate the need for SSI prevention strategies tailored to the preoperative microbiome and resistome present in individual patients.

Salmonella serovars Typhi and Paratyphi cause a prolonged illness known as enteric fever, whereas other serovars cause acute gastroenteritis. Mechanisms responsible for the divergent clinical manifestations of nontyphoidal and enteric fever Salmonella infections have remained elusive. Here, we show that S . Typhi and S . Paratyphi A can persist within human macrophages, whereas S . Typhimurium rapidly induces apoptotic macrophage cell death that is dependent on Salmonella pathogenicity island 2 (SPI2). S . Typhi and S . Paratyphi A lack 12 specific SPI2 effectors with pro-apoptotic functions, including nine that target nuclear factor κB (NF-κB). Pharmacologic inhibition of NF-κB or heterologous expression of the SPI2 effectors GogA or GtgA restores apoptosis of S . Typhi-infected macrophages. In addition, the absence of the SPI2 effector SarA results in deficient signal transducer and activator of transcription 1 (STAT1) activation and interleukin 12 production, leading to impaired T H 1 responses in macrophages and humanized mice. The absence of specific nontyphoidal SPI2 effectors may allow S . Typhi and S . Paratyphi A to cause chronic infections., Importance: Salmonella enterica is a common cause of gastrointestinal infections worldwide. The serovars Salmonella Typhi and Salmonella Paratyphi A cause a distinctive systemic illness called enteric fever, whose pathogenesis is incompletely understood. Here, we show that enteric fever Salmonella serovars lack 12 specific virulence factors possessed by nontyphoidal Salmonella serovars, which allow the enteric fever serovars to persist within human macrophages. We propose that this fundamental difference in the interaction of Salmonella with human macrophages is responsible for the chronicity of typhoid and paratyphoid fever, suggesting that targeting the nuclear factor κB (NF-κB) complex responsible for macrophage survival could facilitate the clearance of persistent bacterial infections., Competing Interests: The authors declare no conflict of interest.

The phrase "gain of function" (GOF) has recently acquired a negative connotation in experimental biology by its association with risky science. Whereas much of the discussion on the relative merits of GOF-type experiments has focused on their risk-benefit equation, relatively little has been said about their epistemic value. In this article, we recount how GOF experiments were critical for establishing DNA as the genetic material, the identification of cellular receptors, and the role of oncogenes in cancer research. Today, many of the products of the biomedical revolution such as synthetic insulin, growth factors, and monoclonal antibodies are the result of GOF experiments where cells were given the new function of synthesizing medically important products. GOF experiments and complementary loss of function experiments are epistemically powerful tools for establishing causality in biology., Competing Interests: The authors declare no conflict of interest.

A total of 199 Gram-negative bacterial isolates from urinary tract infections and 162 from bloodstream infections were collected from 12 healthcare systems throughout the United States between May 2021 and August 2022. The isolates, phenotypically non-susceptible to 2nd or 3rd generation cephalosporins or carbapenems, were characterized through antimicrobial susceptibility testing and whole genome sequence analysis to obtain a broad snapshot of beta-lactamase-mediated resistance among these two sample types. Overall, 23 different carbapenemase genes were detected among 13 species (20.5% of isolates). The bla KPC-3 and bla KPC-2 subtypes were the most common carbapenemase genes identified, followed by bla NDM and the co-carriage of two different bla OXA carbapenemases by Acinetobacter baumannii isolates. All carbapenemase-producing A. baumannii isolates were mCIM negative. Extended-spectrum beta-lactamase genes were identified in 66.2% of isolates; bla CTX-M-15 was the most common. AmpC genes, both plasmid and chromosomal, were detected in 33.2% of isolates. Importantly, 2.8%, 8.3%, and 22.2% of bla KPC -positive organisms were susceptible to ertapenem, imipenem, and meropenem, respectively. The correlation between broth microdilution and disk diffusion results was high for most drugs except cefepime, where the detection of resistance was statistically lower by disk diffusion. Thus, there were gaps in the accuracy of susceptibility testing for some mechanisms of resistance.

Introduction: Acute infectious gastroenteritis (AGE) is a common reason for outpatient visits and hospitalizations in the United States. This study aimed to understand the demographic and clinical characteristics, common pathogens detected, health care resource utilization (HRU), and cost among adult outpatients with AGE visiting US health systems., Methods: A retrospective cohort study was conducted using one of the largest hospital discharge databases (PINC AI Healthcare Database) in the United States. Adult patients (aged ≥18 years) with a principal diagnosis of AGE during an outpatient visit between January 1, 2016, and June 30, 2021, were included. Pathogen detection analysis was performed in those with microbiology data available., Results: Among 248,896 patients, the mean age was 44.3 years (range 18-89+ years), 62.9% were female, and 68.5% were White. More than half (62.0%) of the patients did not have any preexisting comorbidity, and only 18.3% underwent stool workup at the hospital. Most patients (84.7%) were seen in the emergency department, and most (96.4%) were discharged home. Within 30 days of discharge, 1.0% were hospitalized, and 2.8% had another outpatient visit due to AGE. The mean cost of the index visit plus 30-day AGE-related follow-up was $1,338 per patient, amounting to $333,060,182 for the total study population. Among patients with microbiology data available (n = 12,469), common pathogens detected were Clostridioides difficile (32.2%), norovirus (6.3%), and Campylobacter spp. (4.0%)., Discussion: AGE is a common and costly disease affecting adults of all ages and more females than males, including individuals with or without baseline conditions in a hospital-based outpatient setting. C. difficile was the most common pathogen detected., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.)

Background: Shigella spp have been associated with community-wide outbreaks in urban settings. We analysed a sustained shigellosis outbreak in Seattle, WA, USA, to understand its origins and mechanisms of antimicrobial resistance, define ongoing transmission patterns, and optimise strategies for treatment and infection control., Methods: We did a retrospective study of all Shigella isolates identified from stool samples at the clinical laboratories at Harborview Medical Center and University of Washington Medical Center (Seattle, WA, USA) from May 1, 2017, to Feb 28, 2022. We characterised isolates by species identification, phenotypic susceptibility testing, and whole-genome sequencing. Demographic characteristics and clinical outcomes of the patients were retrospectively examined., Findings: 171 cases of shigellosis were included. 78 (46%) patients were men who have sex with men (MSM), and 88 (52%) were people experiencing homelessness (PEH). Although 84 (51%) isolates were multidrug resistant, 100 (70%) of 143 patients with data on antimicrobial therapy received appropriate empirical therapy. Phylogenomic analysis identified sequential outbreaks of multiple distinct lineages of Shigella flexneri and Shigella sonnei. Discrete clonal lineages (ten in S flexneri and nine in S sonnei) and resistance traits were responsible for infection in different at-risk populations (ie, MSM, PEH), enabling development of effective guidelines for empirical treatment. The most prevalent lineage in Seattle was probably introduced to Washington State via international travel, with subsequent domestic transmission between at-risk groups., Interpretation: An outbreak in Seattle was driven by parallel emergence of multidrug-resistant strains involving international transmission networks and domestic transmission between at-risk populations. Genomic analysis elucidated not only outbreak origin, but directed optimal approaches to testing, treatment, and public health response. Rapid diagnostics combined with detailed knowledge of local epidemiology can enable high rates of appropriate empirical therapy even in multidrug-resistant infection., Funding: None., Competing Interests: Declaration of interests We declare no competing interests. GST received research funding from GenMark Dx, for work not pertaining to this project. DRL received a K23 Mentored Research Training Award (1K23AR080209-01) from the National Institutes of Health/National Institute of Arthritis and Musculoskeletal and Skin Disease for work not pertaining to this project. SJS received research grants from Vertex, the Cystic Fibrosis Foundation, and the National Institutes of Health, for work not pertaining to this project. They also received consulting fees from Yale University. CB-C received honoraria for conference presentations on infection prevention and antimicrobial stewardship and received support for attending the meetings for which she received honoraria in 2022: IDWeek, What's New in Medicine, SHEA Spring Conference, and the Providence Annual ID Conference, for work not pertaining to this project. FCF has been a paid consultant to bioMérieux, for work not pertaining to this project. They also received honoraria from Medscape for participation in educational website-based presentations on the diagnosis of enteric infections., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

A retrospective observational study was performed to assess the relationship between diagnostic method (traditional work-up [TW], multiplex PCR panel with < 12 target pathogens [PCR < 12], or multiplex PCR panel with ≥ 12 target pathogens [PCR12]), and diagnostic yield, health care resource use (HRU), and cost in adult outpatients visiting U.S. hospitals for acute infectious gastroenteritis (AGE). Using data from PINC AI Healthcare Database during January 1, 2016-June 30, 2021, we analyzed adult patients with an AGE diagnosis and stool testing performed during an outpatient visit. Detection rates for different pathogens were analyzed for those with microbiology data available. Among 36,787 patients, TW was most often performed (57.0%). PCR12 testing was more frequent in patients from large, urban, and teaching hospitals, compared to TW (all P  < 0.01). PCR12 was associated with a higher mean index visit cost (by $97) but lower mean 30-day AGE-related follow-up cost (by $117) than TW. Patients with PCR12 had a lower 30-day AGE-related hospitalization risk than TW (1.7% versus 2.7% P  < 0.01). Among the 8,451 patients with microbiology data, PCR12 was associated with fewer stool tests per patient (mean 1.61 versus 1.26), faster turnaround time (mean 6.3 versus 25.7 h) and lower likelihood of receiving in-hospital antibiotics (39.4% versus 47.1%, all P  < 0.01) than TW. A higher percentage of patients with PCR12 had a target pathogen detected (73.1%) compared to PCR < 12 (63.6%) or TW (45.4%, P  < 0.01). Thus, we found that large multiplex PCR panels were associated with lower 30-day AGE-related follow-up cost and risk of AGE-related hospitalization, and increased diagnostic yield compared to TW.

Background: In spring of 2022, an outbreak of monkeypox (mpox) spread worldwide. Here, we describe performance characteristics of monkeypox virus (MPXV)-specific and pan-orthopoxvirus qPCR assays for clinical use., Methods: We validated probe-based qPCR assays targeting MPXV-specific loci F3L and G2R (genes MPXVgp052/OPG065 and MPXVgp002 and gp190/OPG002, respectively) and a pan-orthopoxvirus assay targeting the E9L locus (MPXVgp057/OPG071). Clinical samples and synthetic controls were extracted using the Roche MP96 or Promega Maxwell 48 instrument. qPCR was performed on the AB7500 thermocycler. Synthetic control DNA and high concentration clinical samples were quantified by droplet PCR. Cross-reactivity was evaluated for camelpox and cowpox genomic DNA, vaccinia culture supernatant, and HSV- and VZV-positive clinical specimens. We also tested the performance of the F3L assay using dry swabs, Aptima vaginal and rectal swabs, nasopharyngeal, rectal, and oral swabs, cerebrospinal fluid, plasma, serum, whole blood, breastmilk, urine, saliva, and semen., Results: The MPXV-F3L assay is reproducible at a limit of detection (LoD) of 65.6 copies/mL of viral DNA in viral transport medium/universal transport medium (VTM/UTM), or 3.3 copies/PCR reaction. No cross-reactivity with herpesviruses or other poxviruses was observed. MPXV-F3L detects MPXV DNA in alternative specimen types, with an LoD ranging between 260-1000 copies/mL, or 5.7-10 copies/PCR reaction. In clinical swab VTM specimens, MPXV-F3L and MPXV-G2R assays outperformed OPXV-E9L by an average of 2.4 and 2.8 Cts, respectively. MPXV-G2R outperformed MPXV-F3L by 0.4 Cts, consistent with presence of two copies of G2R present in labile inverted terminal repeats (ITRs) of MPXV genome., Conclusions: MPXV is readily detected by qPCR using three clinically validated assays., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: ALG reports contract testing from Abbott, Cepheid, Novavax, Pfizer, Janssen and Hologic and research support from Gilead and Merck, outside of the described work. Dr Kachikis reported serving as a research consultant for Pfizer and GlaxoSmithKline on maternal immunization-related projects in 2020 and as an unpaid consultant for GlaxoSmithKline in 2022 outside the submitted work. Dr Kachikis reported receiving grant support from Merck and Pfizer outside the submitted work., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The sequestration of iron in case of infection, termed nutritional immunity, is an established strategy of host defense. However, the interaction between pathogens and the mammalian iron storage protein ferritin is hitherto not completely understood. To better characterize the function of ferritin in Gram-negative infections, we incubated iron-starved cultures of Salmonella Typhimurium and knockout mutant strains defective for major iron uptake pathways or Escherichia coli with horse spleen ferritin or ionic iron as the sole iron source. Additionally, we added bovine superoxide dismutase and protease inhibitors to the growth medium to assess the effect of superoxide and bacterial proteases, respectively, on Salmonella proliferation and reductive iron release. Compared to free ionic iron, ferritin-bound iron was less available to Salmonella , but was still sufficient to significantly enhance the growth of the bacteria. In the absence of various iron acquisition genes, the availability of ferritin iron further decreased. Supplementation with superoxide dismutase significantly reduced the growth of the Δ entC knockout strain with holoferritin as the sole iron source in comparison with ionic ferrous iron. In contrast, this difference was not observed in the wildtype strain, suggesting that superoxide dismutase undermines bacterial iron uptake from ferritin by siderophore-independent mechanisms. Ferritin seems to diminish iron availability for bacteria in comparison to ionic iron, and its iron sequestering effect could possibly be enhanced by host superoxide dismutase activity.

Pressures to publish, perverse incentives, financial interest and gender are amongst the most commonly discussed risk factors for scientific misconduct. However, evidence of their association with actual data fabrication and falsification is inconclusive. A recent case-controlled analysis of articles containing problematic image duplications suggested that country of affiliation of first and last authors is a significant predictor of scientific misconduct. The same analysis found null or negative associations with individual proxies of publication rate, impact and gender. The latter findings, in line with previous evidence, failed to support common hypotheses about the prevalence and causes of misconduct, but country-level effects may have confounded these results. Here we extend and complete previous results by comparing, via matched-controls analysis, articles from authors in the same country. We found that evidence for individual-level risk factors may be significant in some countries, and null or opposite in others. In particular, in countries where publications are rewarded with cash incentives, and especially China, the risk of problematic image duplication was higher for more productive, more frequently cited, earlier-career researchers working in lower-ranking institutions, in accordance with a "misaligned incentives" explanation for scientific misconduct. However, a null or opposite pattern was observed in all other countries, and especially the USA, UK and Canada, countries where concerns for misaligned incentives are commonly expressed. In line with previous results, we failed to observe a statistically significant association with industry funding and with gender. This is the first direct evidence of a link between publication performance and risk of misconduct and between university ranking and risk of misconduct. Commonly hypothesised individual risk factors for scientific misconduct, including career status and productivity, might be relevant in countries where cash-reward policies generate perverse incentives. In most scientifically active countries, however, where other incentives systems are in place, these patterns are not observed, and other risk factors might be more relevant. Policies to prevent and correct scientific misconduct may need to be tailored to a countries' or institutions' specific context., Competing Interests: "EMB regularly does consulting work on suspected science misconduct cases for publishers and research institutions, and gets speaker’s fees to give talks about research integrity. She is an author on four uBiome (now Psomagen) patents (US20190050534A1 / US20180137239A1 / US20190078142A1 / US20200303070A1). EMB’s company is indicated as an affiliation because she is an independent scholar, but the company did not provide resources that either directly or indirectly contributed to this study. DF advises and investigates allegations of misconduct for the Luxembourg Agency of Research Integrity, for which he receives regular honoraria. This does not alter our adherence to PLOS ONE policies on sharing data and materials."

A variety of eubacteria, plants, and protozoa can modify membrane lipids by cyclopropanation, which is reported to modulate membrane permeability and fluidity. The ability to cyclopropanate membrane lipids has been associated with resistance to oxidative stress in Mycobacterium tuberculosis, organic solvent stress in Escherichia coli, and acid stress in E. coli and Salmonella. In bacteria, the cfa gene encoding cyclopropane fatty acid (CFA) synthase is induced during the stationary phase of growth. In the present study, we constructed a cfa mutant of Salmonella enterica serovar Typhimurium 14028s ( S. Typhimurium) and determined the contribution of CFA-modified lipids to stress resistance and virulence in mice. Cyclopropane fatty acid content was quantified in wild-type and cfa mutant S. Typhimurium. CFA levels in the cfa mutant were greatly reduced compared to CFA levels in the wild type, indicating that CFA synthase is the major enzyme responsible for cyclopropane modification of lipids in Salmonella. S. Typhimurium cfa mutants were more sensitive to extreme acid pH, the protonophore CCCP, and hydrogen peroxide compared to the wild type. In addition, cfa mutants exhibited reduced viability in murine macrophages and could be rescued by the addition of the NADPH phagocyte oxidase inhibitor diphenyleneiodonium (DPI) chloride. S. Typhimurium lacking cfa was also attenuated for virulence in mice. These observations indicate that CFA modification of lipids makes an important contribution to Salmonella virulence.

Efforts to understand molecular mechanisms of pathogenesis of the human-restricted pathogen Salmonella enterica serovar Typhi, the causative agent of typhoid fever, have been hampered by the lack of a tractable small animal model. This obstacle has been surmounted by a humanized mouse model in which genetically modified mice are engrafted with purified CD34+ stem cells from human umbilical cord blood, designated CD34+ Hu-NSG (formerly hu-SRC-SCID) mice. We have shown that these mice develop a lethal systemic infection with S. Typhi that is dependent on the presence of engrafted human hematopoietic cells. Immunological and pathological features of human typhoid are recapitulated in this model, which has been successfully employed for the identification of bacterial genetic determinants of S. Typhi virulence. Here we describe the methods used to infect CD34+ Hu-NSG mice with S. Typhi in humanized mice and to construct and analyze a transposon-directed insertion site sequencing S. Typhi library, and provide general considerations for the use of humanized mice for the study of a human-restricted pathogen., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: An elevated white blood cell count (WBC; >15 000/μL) is an established prognostic marker in patients with Clostridium difficile infection (CDI). Small observational studies have suggested that a markedly elevated WBC should prompt consideration of CDI. However, there is limited evidence correlating WBC elevation with the results of C. difficile nucleic acid amplification testing (NAAT)., Methods: Retrospective review of laboratory testing, outcomes, and treatment of 16 568 consecutive patients presenting to 4 hospitals over 4 years with NAAT and WBC testing on the same day., Results: No significant relationship between C. difficile NAAT results and concurrent WBC in the inpatient setting was observed. Although an elevated WBC did predict NAAT results in the outpatient and emergency department populations (P < .001), accuracy was poor, with receiver-operator areas under the curve of 0.59 and 0.56, respectively. An elevated WBC (>15 000/μL) in CDI was associated with a longer median hospital length of stay (15.5 vs 11.0 days; P < .01), consistent with leukocytosis as a prognostic marker in CDI. NAAT-positive inpatients with elevated WBC were more likely to be treated with metronidazole and/or vancomycin (relative ratio, 1.2; 95% confidence interval [CI], 1.1-1.3) and die in the hospital (relative ratio, 2.9; 95% CI, 2.0-4.3)., Conclusions: Although WBC is an important prognostic indicator in patients with CDI, an isolated WBC elevation has low sensitivity and specificity as a predictor of fecal C. difficile NAAT positivity in the inpatient setting. A high or rising WBC in isolation is not a sufficient indication for CDI testing., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

In this article, the editors of Clinical Infectious Diseases review some of the most important lessons they have learned about the epidemiology, clinical features, diagnosis, treatment and prevention of SARS-CoV-2 infection and identify essential questions about COVID-19 that remain to be answered., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Objective: Noncoding RNAs are emerging as important players in gene regulation and cardiovascular diseases. Their roles in the pathogenesis of atherosclerosis are not fully understood. The purpose of this study was to determine the role played by a previously uncharacterized long noncoding RNA, RP11-728F11.4, in the development of atherosclerosis and the mechanisms by which it acts. Approach and Results: Expression microarray analysis revealed that atherosclerotic plaques had increased expression of RP11-728F11.4 as well as the cognate gene FXYD6 (FXYD domain containing ion transport regulator 6), which encodes a modulator of Na + /K + -ATPase. In vitro experiments showed that RP11-728F11.4 interacted with the RNA-binding protein EWSR1 (Ewings sarcoma RNA binding protein-1) and upregulated FXYD6 expression. Lentivirus-induced overexpression of RP11-728F11.4 in cultured monocytes-derived macrophages resulted in higher Na + /K + -ATPase activity, intracellular cholesterol accumulation, and increased proinflammatory cytokine production. The effects of RP11-728F11.4 were enhanced by siRNA-mediated knockdown of EWSR1 and reduced by downregulation of FXYD domain containing ion transport regulator 6. In vivo experiments in apoE knockout mice fed a Western diet demonstrated that RP11-728F11.4 increased proinflammatory cytokine production and augmented atherosclerotic lesions., Conclusions: RP11-728F11.4 promotes atherosclerosis, with an influence on cholesterol homeostasis and proinflammatory molecule production, thus representing a potential therapeutic target. Graphic Abstract: A graphic abstract is available for this article.

Diagnostic testing has played and will continue to play a major role in the coronavirus disease 2019 (COVID-19) pandemic. The ability to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in respiratory secretions is essential to determine when an individual is infected and potentially infectious to others. Viral detection is used for the identification, management, and isolation of individual patients. Viral detection is also used to determine when the virus has entered a community and how rapidly it is spreading. As communities attempt to reopen following periods of shutdown, the detection of both SARS-CoV-2 and specific antibodies that recognize the virus will become increasingly important as a means to assess infection and immunity in individuals and communities. Here, we discuss questions commonly asked by clinicians about COVID-19 diagnostic testing., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Salmonella enterica serovar Typhimurium is an intracellular pathogen that elicits nitric oxide (NO·) production by host macrophages. NO· is a potent antimicrobial mediator with diverse targets, including protein thiols and metal centers. The mobilization of zinc from metalloproteins by NO· increases the availability of free intracellular zinc, which is detrimental to bacterial cells, but the precise mechanism of zinc cytotoxicity is uncertain. Here, we show that excess zinc results in the mismetallation of the essential iron-containing enzyme peptide deformylase (PDF), thereby diminishing its activity. PDF mismetallation is observed in zinc-treated bacteria lacking the zinc exporters ZntA and ZitB and is also observed during nitrosative stress, suggesting that NO·-mediated zinc mobilization results in PDF mismetallation. However, NO· also inhibits PDF directly by S- nitrosylating the metal-binding Cys90 residue. These observations identify PDF as an essential bacterial protein that is subject to both direct and indirect inactivation by NO·, providing a novel mechanism of zinc toxicity and NO·-mediated antibacterial activity. IMPORTANCE We have previously shown that the host-derived antimicrobial mediator nitric oxide (NO·) mobilizes zinc from bacterial metalloproteins. The present study demonstrates that NO· inactivates the essential iron-containing enzyme peptide deformylase, both by promoting its mismetallation by zinc and by directly modifying its metal-binding site. We explain how free intracellular zinc is detrimental for cells and reveal a new mechanism of NO·-mediated bacterial growth inhibition that is distinct from previously known targets., (Copyright © 2020 Singhal and Fang.)

Background: Campylobacter species are among the most common causes of enteric bacterial infections worldwide. Men who have sex with men (MSM) are at increased risk for sexually transmitted enteric infections, including globally distributed strains of multidrug-resistant Shigella species., Methods: This was a retrospective study of MSM-associated Campylobacter in Seattle, Washington and Montréal, Québec with phenotypic antimicrobial resistance profiles and whole genome sequencing (WGS)., Results: We report the isolation of 2 clonal lineages of multidrug-resistant Campylobacter coli from MSM in Seattle and Montréal. WGS revealed nearly identical strains obtained from the 2 regions over a 4-year period. Comparison with the National Center for Biotechnology Information's Pathogen Detection database revealed extensive Campylobacter species clusters carrying multiple drug resistance genes that segregated with these isolates. Examination of the genetic basis of antimicrobial resistance revealed multiple macrolide resistance determinants including a novel ribosomal RNA methyltransferase situated in a CRISPR (clustered regularly interspaced short palindromic repeats) array locus in a C. coli isolate., Conclusions: As previously reported for Shigella, specific multidrug-resistant strains of Campylobacter are circulating by sexual transmission in MSM populations across diverse geographic locations, suggesting a need to incorporate sexual behavior in the investigation of clusters of foodborne pathogens revealed by WGS data., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America.)

Nitric oxide (NO˙) is a radical molecule produced by mammalian phagocytic cells as part of the innate immune response to bacterial pathogens. It exerts its antimicrobial activity in part by impairing the function of metalloproteins, particularly those containing iron and zinc cofactors. The pathogenic Gram-negative bacterium Salmonella enterica serovar typhimurium undergoes dynamic changes in its cellular content of the four most common metal cofactors following exposure to NO˙ stress. Zinc, iron and magnesium all decrease in response to NO˙ while cellular manganese increases significantly. Manganese acquisition is driven primarily by increased expression of the mntH and sitABCD transporters following derepression of MntR and Fur. ZupT also contributes to manganese acquisition in response to nitrosative stress. S. Typhimurium mutants lacking manganese importers are more sensitive to NO˙, indicating that manganese is important for resistance to nitrosative stress.

Background: Men who have sex with men (MSM) are at risk for sexual transmission of enteric pathogens. The microbiology of gastroenteritis in MSM has not been examined since the advent of antiretroviral therapy and molecular diagnostics. Our objective was to assess the causes of gastroenteritis among MSM living with and without human immunodeficiency virus (HIV) coinfection in Seattle, Washington., Methods: We conducted a retrospective cohort study of 235 MSM who underwent multiplex stool polymerase chain reaction (PCR) testing between 1 January 2017 and 1 June 2018. We abstracted clinical and laboratory data from electronic medical records. Parallel or reflexive culture and susceptibility testing were performed when PCR detected cultivable pathogens., Results: Among 235 MSM tested (268 episodes), 131 had 151 episodes with positive test results. 148 (63.0%) individuals were living with HIV. Among positive tests, 88.7% detected a bacterial pathogen, 26% a virus, and 40% a parasite. Diarrheagenic Escherichia coli (enteroaggretative, enteropathogenic), Shigella, and Campylobacter were the most commonly detected bacteria (33.1%, 30.5%, and 17.2% of positive samples, respectively). Forty-three percent of positive specimens had ≥2 pathogens. Etiologies and clinical presentations were similar between men living with and without HIV. Cultured Shigella and Campylobacter isolates were frequently resistant to multiple antibiotics., Conclusions: MSM present with gastroenteritis from varied pathogens, including some not detected by conventional stool culture. High levels of antibiotic resistance are consistent with frequent antibiotic exposure in this population and the transmission of multiresistant strains. New approaches are needed to detect, treat, and prevent enteric infections in MSM., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Two near-identical clinical Streptococcus pyogenes isolates of emm subtype emm43.4 with a pbp2x missense mutation (T553K) were detected. Minimum inhibitory concentrations (MICs) for ampicillin and amoxicillin were 8-fold higher, and the MIC for cefotaxime was 3-fold higher than for near-isogenic control isolates, consistent with a first step in developing β-lactam resistance., (Published by Oxford University Press for the Infectious Diseases Society of America 2019.)

Gene duplication facilitates the evolution of biological complexity, as one copy of a gene retains its original function while a duplicate copy can acquire mutations that would otherwise diminish fitness. Duplication has played a particularly important role in the evolution of regulatory networks by permitting novel regulatory interactions and responses to stimuli. The diverse MarR family of transcription factors (MFTFs) illustrate this concept, ranging from highly specific repressors of single operons to pleiotropic global regulators controlling hundreds of genes. MFTFs are often genetically and functionally linked to antimicrobial efflux systems. However, the SlyA MFTF lineage in the Enterobacteriaceae plays little or no role in regulating efflux but rather functions as transcriptional counter-silencers, which alleviate xenogeneic silencing of horizontally acquired genes and facilitate bacterial evolution by horizontal gene transfer. This review will explore recent advances in our understanding of MFTF traits that have contributed to their functional evolution., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Periodontal diseases are infectious diseases that are characterized by progressive damage to dental support tissue. The major goal of periodontal therapy is to regenerate the periodontium destroyed by periodontal diseases. Human periodontal ligament (PDL) tissue possesses periodontal regenerative properties, and periodontal ligament stem cells (PDLSCs) with the capacity for osteogenic differentiation show strong potential in clinical application for periodontium repair and regeneration. Noncoding RNAs (ncRNAs), which include a substantial portion of poly-A tail mature RNAs, are considered "transcriptional noise." Recent studies show that ncRNAs play a major role in PDLSC differentiation; therefore, exploring how ncRNAs participate in the osteogenic differentiation of PDLSCs may help to elucidate the underlying mechanism of the osteogenic differentiation of PDLSCs and further shed light on the potential of stem cell transplantation for periodontium regeneration. In this review paper, we discuss the history of PDLSC research and highlight the regulatory mechanism of ncRNAs in the osteogenic differentiation of PDLSCs., Competing Interests: Conflict-of-interest statement: The authors declare that they have no conflict of interest., (©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.)

The intracellular pathogen concept classifies pathogenic microbes on the basis of their site of replication and dependence on host cells. This concept played a fundamental role in establishing the field of cellular microbiology, founded in part by Dr. Pascale Cossart, whose seminal contributions are honored in this issue of Molecular Microbiology. The recognition that microbes can access and replicate in privileged compartments within host cells has led to many new and fruitful lines of investigation into the biology of the cell and mechanisms of cell-mediated immunity. However, like any scientific concept, the intracellular pathogen concept can become a dogma that constrains thinking and oversimplifies complex and dynamic host-pathogen interactions. Growing evidence has blurred the distinction between "intracellular" and "extracellular" pathogens and demonstrated that many pathogens can exist both within and outside of cells. Although the intracellular pathogen concept remains useful, it should not be viewed as a rigid classification of pathogenic microbes, which exhibit remarkable variation and complexity in their behavior in the host., (© 2019 John Wiley & Sons Ltd.)

PCR ribotyping and antimicrobial susceptibility testing were used to characterize 940 Clostridioides (Clostridium) difficile isolates collected from 26 U S. hospitals over three time periods from 2011 to 2017. The proportion of ribotype (RT) 027 isolated during the three surveys decreased significantly over time from 31% in 2011-2012, to 22% in 2013-2014, and to 14% in 2015-2017 (p < 0.001 and p = 0.010, respectively), while we observed an increase in prevalence of RT106, that rose from 7% in our first survey to 19% of isolates in our last survey (p < 0.001). In addition, both RT056 and RT002 rose from 3% to 10% (p < 0.001). The proportions of all other ribotypes remained steady over time, and RT014/020 was the third most common strain type in our convenience sample in the final survey. Overall, resistance to moxifloxacin, rifampin, and vancomycin decreased during our studies, mainly due to the decline in RT027 isolates. A decrease in moxifloxacin resistance and an increase in tetracycline resistance were found among RT027 strains isolated in the last survey. Although the proportion of RT027 isolates declined, multidrug resistance among this ribotype continues to be common., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

We aim to describe the characteristics, risk factors, and clinical outcomes associated with NAP1 strain Clostridioides difficile infection (CDI) in this single-center, retrospective, case-control (1:1) study. We found that the NAP1 strain accounted for 19.7% of CDI, and risk factors for acquisition included residence in skilled nursing facilities, previous CDI, and proton pump inhibitor use., (© The Author(s) 2019. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Medicopsis species are rare fungal pathogens that frequently resist common antifungal therapies and are difficult to identify morphologically as conidia are produced in pycnidia, a key feature of coelomycetes. Immunocompromised patients are at risk of these infections, even after remote exposure, and typically present with phaeohyphomycoses without dissemination. We present the case of a renal transplant recipient 6.5 years post-transplant who developed a slowly progressive soft tissue infection mimicking a synovial cyst. A cultured isolate was identified as Medicopsis romeroi by sequencing of multiple ribosomal loci. The patient responded well to debridement and posaconazole therapy. Solid-organ transplant patients are at risk of opportunistic fungal infection long after transplant, and molecular methods are often required for definitive identification.

Reactive nitrogen species play diverse and essential roles in host-pathogen interactions. Here, we review selected recent discoveries regarding nitric oxide (NO) in host defense and the pathogenesis of infection, mechanisms of bacterial NO resistance, production of NO by human macrophages, NO-based antimicrobial therapeutics and NO interactions with the gut microbiota., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Salmonella enterica serovar Typhi causes typhoid fever only in humans. Murine infection with S. Typhimurium is used as a typhoid model, but its relevance to human typhoid is limited. Non-obese diabetic-scid IL2rγnull mice engrafted with human hematopoietic stem cells (hu-SRC-SCID) are susceptible to lethal S. Typhi infection. In this study, we use a high-density S. Typhi transposon library in hu-SRC-SCID mice to identify virulence loci using transposon-directed insertion site sequencing (TraDIS). Vi capsule, lipopolysaccharide (LPS), and aromatic amino acid biosynthesis were essential for virulence, along with the siderophore salmochelin. However, in contrast to the murine S. Typhimurium model, neither the PhoPQ two-component system nor the SPI-2 pathogenicity island was required for lethal S. Typhi infection, nor was the CdtB typhoid toxin. These observations highlight major differences in the pathogenesis of typhoid and non-typhoidal Salmonella infections and demonstrate the utility of humanized mice for understanding the pathogenesis of a human-specific pathogen., (Copyright © 2019 Elsevier Inc. All rights reserved.)

It is commonly hypothesized that scientists are more likely to engage in data falsification and fabrication when they are subject to pressures to publish, when they are not restrained by forms of social control, when they work in countries lacking policies to tackle scientific misconduct, and when they are male. Evidence to test these hypotheses, however, is inconclusive due to the difficulties of obtaining unbiased data. Here we report a pre-registered test of these four hypotheses, conducted on papers that were identified in a previous study as containing problematic image duplications through a systematic screening of the journal PLoS ONE. Image duplications were classified into three categories based on their complexity, with category 1 being most likely to reflect unintentional error and category 3 being most likely to reflect intentional fabrication. We tested multiple parameters connected to the hypotheses above with a matched-control paradigm, by collecting two controls for each paper containing duplications. Category 1 duplications were mostly not associated with any of the parameters tested, as was predicted based on the assumption that these duplications were mostly not due to misconduct. Categories 2 and 3, however, exhibited numerous statistically significant associations. Results of univariable and multivariable analyses support the hypotheses that academic culture, peer control, cash-based publication incentives and national misconduct policies might affect scientific integrity. No clear support was found for the "pressures to publish" hypothesis. Female authors were found to be equally likely to publish duplicated images compared to males. Country-level parameters generally exhibited stronger effects than individual-level parameters, because developing countries were significantly more likely to produce problematic image duplications. This suggests that promoting good research practices in all countries should be a priority for the international research integrity agenda.

Gene duplication and subsequent evolutionary divergence have allowed conserved proteins to develop unique roles. The MarR family of transcription factors (TFs) has undergone extensive duplication and diversification in bacteria, where they act as environmentally responsive repressors of genes encoding efflux pumps that confer resistance to xenobiotics, including many antimicrobial agents. We have performed structural, functional, and genetic analyses of representative members of the SlyA/RovA lineage of MarR TFs, which retain some ancestral functions, including repression of their own expression and that of divergently transcribed multidrug efflux pumps, as well as allosteric inhibition by aromatic carboxylate compounds. However, SlyA and RovA have acquired the ability to countersilence horizontally acquired genes, which has greatly facilitated the evolution of Enterobacteriaceae by horizontal gene transfer. SlyA/RovA TFs in different species have independently evolved novel regulatory circuits to provide the enhanced levels of expression required for their new role. Moreover, in contrast to MarR, SlyA is not responsive to copper. These observations demonstrate the ability of TFs to acquire new functions as a result of evolutionary divergence of both cis -regulatory sequences and in trans interactions with modulatory ligands. IMPORTANCE Bacteria primarily evolve via horizontal gene transfer, acquiring new traits such as virulence and antibiotic resistance in single transfer events. However, newly acquired genes must be integrated into existing regulatory networks to allow appropriate expression in new hosts. This is accommodated in part by the opposing mechanisms of xenogeneic silencing and countersilencing. An understanding of these mechanisms is necessary to understand the relationship between gene regulation and bacterial evolution. Here we examine the functional evolution of an important lineage of countersilencers belonging to the ancient MarR family of classical transcriptional repressors. We show that although members of the SlyA lineage retain some ancestral features associated with the MarR family, their cis -regulatory sequences have evolved significantly to support their new function. Understanding the mechanistic requirements for countersilencing is critical to understanding the pathoadaptation of emerging pathogens and also has practical applications in synthetic biology., (Copyright © 2019 Will et al.)

Noncoding RNAs are emerging as important players in gene regulation and disease pathogeneses. Here, we show that a previously uncharacterized long noncoding RNA, nexilin F-actin binding protein antisense RNA 1 (NEXN-AS1), modulates the expression of the actin-binding protein NEXN and that NEXN exerts a protective role against atherosclerosis. An expression microarray analysis showed that the expression of both NEXN-AS1 and NEXN was reduced in human atherosclerotic plaques. In vitro experiments revealed that NEXN-AS1 interacted with the chromatin remodeler BAZ1A and the 5' flanking region of the NEXN gene and that it also upregulated NEXN expression. Augmentation of NEXN-AS1 expression inhibited TLR4 oligomerization and NF-κB activity, downregulated the expression of adhesion molecules and inflammatory cytokines by endothelial cells, and suppressed monocyte adhesion to endothelial cells. These inhibitory effects of NEXN-AS1 were abolished by knockdown of NEXN. In vivo experiments using ApoE-knockout mice fed a Western high-fat diet demonstrated that NEXN deficiency promoted atherosclerosis and increased macrophage abundance in atherosclerotic lesions, with heightened expression of adhesion molecules and inflammatory cytokines, whereas augmented NEXN expression deterred atherosclerosis. Patients with coronary artery disease were found to have lower blood NEXN levels than healthy individuals. These results indicate that NEXN-AS1 and NEXN represent potential therapeutic targets in atherosclerosis-related diseases.

We have recently shown that the catecholamine dopamine regulates cellular iron homeostasis in macrophages. As iron is an essential nutrient for microbes, and intracellular iron availability affects the growth of intracellular bacteria, we studied whether dopamine administration impacts the course of Salmonella infections. Dopamine was found to promote the growth of Salmonella both in culture and within bone marrow-derived macrophages, which was dependent on increased bacterial iron acquisition. Dopamine administration to mice infected with Salmonella enterica serovar Typhimurium resulted in significantly increased bacterial burdens in liver and spleen, as well as reduced survival. The promotion of bacterial growth by dopamine was independent of the siderophore-binding host peptide lipocalin-2. Rather, dopamine enhancement of iron uptake requires both the histidine sensor kinase QseC and bacterial iron transporters, in particular SitABCD, and may also involve the increased expression of bacterial iron uptake genes. Deletion or pharmacological blockade of QseC reduced but did not abolish the growth-promoting effects of dopamine. Dopamine also modulated systemic iron homeostasis by increasing hepcidin expression and depleting macrophages of the iron exporter ferroportin, which enhanced intracellular bacterial growth. Salmonella lacking all central iron uptake pathways failed to benefit from dopamine treatment. These observations are potentially relevant to critically ill patients, in whom the pharmacological administration of catecholamines to improve circulatory performance may exacerbate the course of infection with siderophilic bacteria. IMPORTANCE Here we show that dopamine increases bacterial iron incorporation and promotes Salmonella Typhimurium growth both in vitro and in vivo These observations suggest the potential hazards of pharmacological catecholamine administration in patients with bacterial sepsis but also suggest that the inhibition of bacterial iron acquisition might provide a useful approach to antimicrobial therapy., (Copyright © 2019 Dichtl et al.)

We describe the rapid and ongoing emergence across multiple US cities of a new multidrug-resistant Escherichia coli clone-sequence type (ST) 1193-resistant to fluoroquinolones (100%), trimethoprim-sulfamethoxazole (55%), and tetracycline (53%). ST1193 is associated with younger adults (age <40 years) and currently comprises a quarter of fluoroquinolone-resistant clinical E. coli urine isolates.