scholarly journals Decontamination Effect of the Spindle and 222-Nanometer Krypton-Chlorine Excimer Lamp Combination against Pathogens on Apples (Malus domesticaBorkh.) and Bell Peppers (Capsicum annuumL.)

2019 ◽  
Vol 85 (12) ◽  
Author(s):  
Jun-Won Kang ◽  
Dong-Hyun Kang
Keyword(s):  
Pathogenic Bacteria ◽  
Fresh Produce ◽  
Free Water ◽  
Consumer Preference ◽  
Sample Surface ◽  
Bell Pepper ◽  
Tween 20 ◽  
Content Type ◽  
Excimer Lamp ◽  
Serovar Typhimurium

ABSTRACTIn this study, we developed a washing system capable of decontaminating fresh produce by combining the Spindle apparatus, which detaches microorganisms on sample surfaces, and a 222-nm krypton-chlorine excimer lamp (KrCl excilamp) (Sp-Ex) and investigated their decontamination effect againstEscherichia coliO157:H7,Salmonella entericaserovar Typhimurium, andListeria monocytogeneson apple (Malus domesticaBorkh.) and bell pepper (Capsicum annuumL.) surfaces. Initial levels of the three pathogens were approximately 108CFU/sample. BothE. coliO157:H7 andS.Typhimurium were reduced to below the detection limit (2.0 log CFU/sample) after 5 and 7 min of treatment on apple and bell pepper surfaces, respectively. The amounts ofL. monocytogeneson apple and bell pepper surfaces were reduced by 4.26 and 5.48 logs, respectively, after 7 min of treatment. The decontamination effect of the Sp-Ex was influenced by the hydrophobicity of the sample surface as well as the microbial cell surface, and the decontamination effect decreased as the two hydrophobicity values increased. To improve the decontamination effect of the Sp-Ex, Tween 20, a surfactant that weakens the hydrophobic interaction between the sample surface and pathogenic bacteria, was incorporated into Sp-Ex processing. It was found that its decontamination effect was significantly (P < 0.05) increased by the addition of 0.1% Tween 20. Sp-Ex did not cause significant quality changes in apple or bell pepper surfaces during 7 days storage following treatment (P > 0.05). Our results suggest that Sp-Ex could be applied as a system to control pathogens in place of chemical sanitizer washing by the fresh-produce industry.IMPORTANCEAlthough most fresh-produce processing currently controls pathogens by means of washing with sanitizers, there are still problems such as the generation of harmful substances and changes in product quality. A combination system composed of the Spindle and a 222-nm KrCl excilamp (Sp-Ex) developed in this study reduced pathogens on apple and bell pepper surfaces using sanitizer-free water without altering produce color and texture. This study demonstrates the potential of the Sp-Ex to replace conventional washing with sanitizers, and it can be used as baseline data for practical application by industry. In addition, implementation of the Sp-Ex developed in this study is expected not only to meet consumer preference for fresh, minimally processed produce but also to reduce human exposure to harmful chemicals while being beneficial to the environment.

scholarly journals Quinazoline-Based Antivirulence Compounds Selectively Target Salmonella PhoP/PhoQ Signal Transduction System

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
María Ayelén Carabajal ◽  
Christopher R. M. Asquith ◽  
Tuomo Laitinen ◽  
Graham J. Tizzard ◽  
Lucía Yim ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Catalytic Domain ◽  
Kinase Inhibitor ◽  
Adaptive Responses ◽  
Antibacterial Compounds ◽  
Content Type ◽  
Two Component ◽  
Serovar Typhimurium

ABSTRACT The rapid emergence of multidrug resistance among bacterial pathogens has become a significant challenge to human health in our century. Therefore, development of next-generation antibacterial compounds is an urgent need. Two-component signal transduction systems (TCS) are stimulus-response coupling devices that allow bacteria to sense and elaborate adaptive responses to changing environmental conditions, including the challenges that pathogenic bacteria face inside the host. The differential presence of TCS, present in bacteria but absent in the animal kingdom, makes them attractive targets in the search for new antibacterial compounds. In Salmonella enterica, the PhoP/PhoQ two-component system controls the expression of crucial phenotypes that define the ability of the pathogen to establish infection in the host. We now report the screening of 686 compounds from a GlaxoSmithKline published kinase inhibitor set in a high-throughput whole-cell assay that targets Salmonella enterica serovar Typhimurium PhoP/PhoQ. We identified a series of quinazoline compounds that showed selective and potent downregulation of PhoP/PhoQ-activated genes and define structural attributes required for their efficacy. We demonstrate that their bioactivity is due to repression of the PhoQ sensor autokinase activity mediated by interaction with its catalytic domain, acting as competitive inhibitors of ATP binding. While noncytotoxic, the hit molecules exhibit antivirulence effect by blockage of S. Typhimurium intramacrophage replication. Together, these features make these quinazoline compounds stand out as exciting leads to develop a therapeutic intervention to fight salmonellosis.

scholarly journals Residual Antibiotics Disrupt Meat Fermentation and Increase Risk of Infection

mBio ◽  
2012 ◽  
Vol 3 (5) ◽  
Author(s):  
Jette Kjeldgaard ◽  
Marianne T. Cohn ◽  
Pat G. Casey ◽  
Colin Hill ◽  
Hanne Ingmer
Keyword(s):  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Starter Cultures ◽  
Farm Animals ◽  
Veterinary Antibiotics ◽  
Growth Promoters ◽  
Content Type ◽  
Fermented Sausages ◽  
Serovar Typhimurium ◽  
Meat Fermentation

ABSTRACTFermented sausages, although presumed safe for consumption, sometimes cause serious bacterial infections in humans that may be deadly. Not much is known about why and when this is the case. We tested the hypothesis that residual veterinary antibiotics in meat can disrupt the fermentation process, giving pathogenic bacteria a chance to survive and multiply. We found that six commercially available starter cultures were susceptible to commonly used antibiotics, namely, oxytetracycline, penicillin, and erythromycin. In meat, statutorily tolerable levels of oxytetracycline and erythromycin inhibited fermentation performance of three and five of the six starter cultures, respectively. In model sausages, the disruption of meat fermentation enhanced survival of the pathogensEscherichia coliO157:H7 andSalmonella entericaserovar Typhimurium compared to successful fermentations. Our work reveals an overlooked risk associated with the presence of veterinary drugs in meat.IMPORTANCEAntibiotics have for a long time been used as growth promoters in farm animals, and while they are banned as such in Europe, their clinical use in farm animals still accounts for the majority of consumption. Here, we examined how acceptable levels of antibiotics in meat influence fermentation. Our results show that commonly used bacterial starter cultures are sensitive to residual antibiotics at or near statutorily tolerable levels, and as a result, processed sausages may indeed contain high levels of pathogens. Our findings provide a possible explanation for outbreaks and disease cases associated with consumption of fermented sausages and offer yet another argument for limiting the use of antimicrobials in farm animals.

scholarly journals Contribution of Asparagine Catabolism to Salmonella Virulence

2016 ◽  
Vol 85 (2) ◽  
Author(s):  
Patrick A. McLaughlin ◽  
Michael McClelland ◽  
Hee-Jeong Yang ◽  
Steffen Porwollik ◽  
Lydia Bogomolnaya ◽  
...  
Keyword(s):  
T Cell ◽  
Pathogenic Bacteria ◽  
Protein A ◽  
Metabolic Reprogramming ◽  
Wild Type ◽  
Content Type ◽  
Cell Responses ◽  
Serovar Typhimurium ◽  
Salmonella Virulence ◽  
And Function

ABSTRACT Salmonellae are pathogenic bacteria that cause significant morbidity and mortality in humans worldwide. Salmonellae establish infection and avoid clearance by the immune system by mechanisms that are not well understood. We previously showed that l-asparaginase II produced by Salmonella enterica serovar Typhimurium (S. Typhimurium) inhibits T cell responses and mediates virulence. In addition, we previously showed that asparagine deprivation such as that mediated by l-asparaginase II of S. Typhimurium causes suppression of activation-induced T cell metabolic reprogramming. Here, we report that STM3997, which encodes a homolog of disulfide bond protein A (dsbA) of Escherichia coli, is required for l-asparaginase II stability and function. Furthermore, we report that l-asparaginase II localizes primarily to the periplasm and acts together with l-asparaginase I to provide S. Typhimurium the ability to catabolize asparagine and assimilate nitrogen. Importantly, we determined that, in a murine model of infection, S. Typhimurium lacking both l-asparaginase I and II genes competes poorly with wild-type S. Typhimurium for colonization of target tissues. Collectively, these results indicate that asparagine catabolism contributes to S. Typhimurium virulence, providing new insights into the competition for nutrients at the host-pathogen interface.

scholarly journals Heterologous Expression of Der Homologs in an Escherichia coli der Mutant and Their Functional Complementation

2016 ◽  
Vol 198 (17) ◽  
pp. 2284-2296 ◽  
Author(s):  
Eunsil Choi ◽  
Nalae Kang ◽  
Young Jeon ◽  
Hyun-Sook Pai ◽  
Sung-Gun Kim ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pathogenic Bacteria ◽  
Ribosomal Subunit ◽  
Functional Complementation ◽  
Ribosomal Subunits ◽  
Content Type ◽  
E Coli ◽  
Serovar Typhimurium ◽  
Species Specific ◽  
Null Strain

ABSTRACTThe uniqueEscherichia coliGTPase Der (double Era-like GTPase), which contains tandemly repeated GTP-binding domains, has been shown to play an essential role in 50S ribosomal subunit biogenesis. The depletion of Der results in the accumulation of precursors of 50S ribosomal subunits that are structurally unstable at low Mg2+concentrations. Der homologs are ubiquitously found in eubacteria. Conversely, very few are conserved in eukaryotes, and none is conserved in archaea. In the present study, to verify their conserved role in bacterial 50S ribosomal subunit biogenesis, we cloned Der homologs from two gammaproteobacteria,Klebsiella pneumoniaeandSalmonella entericaserovar Typhimurium; two pathogenic bacteria,Staphylococcus aureusandNeisseria gonorrhoeae; and the extremophileDeinococcus radioduransand then evaluated whether they could functionally complement theE. colider-null phenotype. OnlyK. pneumoniaeandS. Typhimurium Der proteins enabled theE. coli der-null strain to grow under nonpermissive conditions. Sucrose density gradient experiments revealed that the expression ofK. pneumoniaeandS. Typhimurium Der proteins rescued the structural instability of 50S ribosomal subunits, which was caused byE. coliDer depletion. To determine what allows their complementation, we constructed Der chimeras. We found that only Der chimeras harboring both the linker and long C-terminal regions could reverse the growth defects of theder-null strain. Our findings suggest that ubiquitously conserved essential GTPase Der is involved in 50S ribosomal subunit biosynthesis in various bacteria and that the linker and C-terminal regions may participate in species-specific recognition or interaction with the 50S ribosomal subunit.IMPORTANCEInEscherichia coli, Der (double Era-like GTPase) is an essential GTPase that is important for the production of mature 50S ribosomal subunits. However, to date, its precise role in ribosome biogenesis has not been clarified. In this study, we used five Der homologs from gammaproteobacteria, pathogenic bacteria, and an extremophile to elucidate their conserved function in 50S ribosomal subunit biogenesis. Among them,Klebsiella pneumoniaeandSalmonella entericaserovar Typhimurium Der homologs implicated the participation of Der in ribosome assembly inE. coli. Our results show that the linker and C-terminal regions of Der homologs are correlated with its functional complementation inE. coli dermutants, suggesting that they are involved in species-specific recognition or interaction with 50S ribosomal subunits.

scholarly journals Bacterium-Derived Cell-Penetrating Peptides Deliver Gentamicin To Kill Intracellular Pathogens

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Marta Gomarasca ◽  
Thaynan F. C. Martins ◽  
Lilo Greune ◽  
Philip R. Hardwidge ◽  
M. Alexander Schmidt ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Shigella Flexneri ◽  
Cell Penetrating Peptides ◽  
Biologically Active ◽  
Intracellular Pathogens ◽  
Content Type ◽  
Cell Penetrating ◽  
Serovar Typhimurium ◽  
Therapeutic Tools

ABSTRACT Commonly used antimicrobials show poor cellular uptake and often have limited access to intracellular targets, resulting in low antimicrobial activity against intracellular pathogens. An efficient delivery system to transport these drugs to the intracellular site of action is needed. Cell-penetrating peptides (CPPs) mediate the internalization of biologically active molecules into the cytoplasm. Here, we characterized two CPPs, α1H and α2H, derived from the Yersinia enterocolitica YopM effector protein. These CPPs, as well as Tat (trans-activator of transcription) from HIV-1, were used to deliver the antibiotic gentamicin to target intracellular bacteria. The YopM-derived CPPs penetrated different endothelial and epithelial cells to the same extent as Tat. CPPs were covalently conjugated to gentamicin, and CPP-gentamicin conjugates were used to target infected cells to kill multiple intracellular Gram-negative pathogenic bacteria, including Escherichia coli K1, Salmonella enterica serovar Typhimurium, and Shigella flexneri. Taken together, CPPs show great potential as delivery vehicles for antimicrobial agents and may contribute to the generation of new therapeutic tools to treat infectious diseases caused by intracellular pathogens.

scholarly journals Factors Required for Adhesion of Salmonella enterica Serovar Typhimurium to Corn Salad (Valerianella locusta)

2020 ◽  
Vol 86 (8) ◽  
Author(s):  
Laura Elpers ◽  
Juliane Kretzschmar ◽  
Sean-Paul Nuccio ◽  
Andreas J. Bäumler ◽  
Michael Hensel
Keyword(s):  
Salmonella Enterica ◽  
Fresh Produce ◽  
Animal Origin ◽  
Synthetic Approach ◽  
Secretion Systems ◽  
Surface Binding ◽  
Minimally Processed ◽  
Content Type ◽  
Food Of Animal Origin ◽  
Serovar Typhimurium

ABSTRACT Salmonella enterica is a foodborne pathogen often leading to gastroenteritis and is commonly acquired by consumption of contaminated food of animal origin. However, frequency of outbreaks linked to the consumption of fresh or minimally processed food of nonanimal origin is increasing. New infection routes of S. enterica by vegetables, fruits, nuts, and herbs have to be considered. This leads to special interest in S. enterica interactions with leafy products, e.g., salads, that are mainly consumed in a minimally processed form. The attachment of S. enterica to salad is a crucial step in contamination, but little is known about the bacterial factors required and mechanisms of adhesion. S. enterica possesses a complex set of adhesive structures whose functions are only partly understood. Potentially, S. enterica may deploy multiple adhesive strategies for adhering to various salad species and other vegetables. In this study, we systematically analyzed the contributions of the complete adhesiome, of lipopolysaccharide (LPS), and of flagellum-mediated motility of S. enterica serovar Typhimurium (STM) in adhesion to Valerianella locusta (corn salad). We deployed a reductionist, synthetic approach to identify factors involved in the surface binding of STM to leaves of corn salad, with particular regard to the expression of all known adhesive structures, using the Tet-on system. This work reveals the contribution of Saf fimbriae, type 1 secretion system-secreted BapA, an intact LPS, and flagellum-mediated motility of STM in adhesion to corn salad leaves. IMPORTANCE Transmission of gastrointestinal pathogens by contaminated fresh produce is of increasing relevance to human health. However, the mechanisms of contamination of, persistence on, and transmission by fresh produce are poorly understood. We investigated the contributions of the various adhesive structures of STM to the initial event in transmission, i.e., binding to the plant surface. A reductionist system was used that allowed experimentally controlled surface expression of individual adhesive structures and analyses of the contribution to binding to leave surfaces of corn salad under laboratory conditions. The model system allowed the determination of the relative contributions of fimbrial and nonfimbrial adhesins, the type 3 secretion systems, the O antigen of lipopolysaccharide, the flagella, and chemotaxis of STM to binding to corn salad leaves. Based on these data, future work could reveal the mechanism of binding and the relevance of interaction under agricultural conditions.

scholarly journals Bistable Expression of CsgD in Salmonella enterica Serovar Typhimurium Connects Virulence to Persistence

2015 ◽  
Vol 83 (6) ◽  
pp. 2312-2326 ◽  
Author(s):  
Keith D. MacKenzie ◽  
Yejun Wang ◽  
Dylan J. Shivak ◽  
Cynthia S. Wong ◽  
Leia J. L. Hoffman ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Single Cells ◽  
Smooth Transition ◽  
Intestinal Cell ◽  
Planktonic Cells ◽  
Multicellular Aggregate ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Cell Subpopulations

Pathogenic bacteria often need to survive in the host and the environment, and it is not well understood how cells transition between these equally challenging situations. For the human and animal pathogenSalmonella entericaserovar Typhimurium, biofilm formation is correlated with persistence outside a host, but the connection to virulence is unknown. In this study, we analyzed multicellular-aggregate and planktonic-cell subpopulations that coexist whenS. Typhimurium is grown under biofilm-inducing conditions. These cell types arise due to bistable expression of CsgD, the central biofilm regulator. Despite being exposed to the same stresses, the two cell subpopulations had 1,856 genes that were differentially expressed, as determined by transcriptome sequencing (RNA-seq). Aggregated cells displayed the characteristic gene expression of biofilms, whereas planktonic cells had enhanced expression of numerous virulence genes. Increased type three secretion synthesis in planktonic cells correlated with enhanced invasion of a human intestinal cell line and significantly increased virulence in mice compared to the aggregates. However, when the same groups of cells were exposed to desiccation, the aggregates survived better, and the competitive advantage of planktonic cells was lost. We hypothesize that CsgD-based differentiation is a form of bet hedging, with single cells primed for host cell invasion and aggregated cells adapted for persistence in the environment. This allowsS. Typhimurium to spread the risks of transmission and ensures a smooth transition between the host and the environment.

scholarly journals Stress-Induced Block in Dicarboxylate Uptake and Utilization in Salmonella enterica Serovar Typhimurium

2021 ◽  
Vol 203 (9) ◽  
Author(s):  
Steven J. Hersch ◽  
Bojana Radan ◽  
Bushra Ilyas ◽  
Patrick Lavoie ◽  
William Wiley Navarre
Keyword(s):  
Pathogenic Bacteria ◽  
Constitutive Expression ◽  
Elongation Factor ◽  
Stringent Response ◽  
Close Relative ◽  
Content Type ◽  
Growth And Survival ◽  
E Coli ◽  
Serovar Typhimurium ◽  
Sense And Respond

ABSTRACT Bacteria have evolved to sense and respond to their environment by altering gene expression and metabolism to promote growth and survival. In this work, we demonstrate that Salmonella displays an extensive (>30-h) lag in growth when subcultured into medium where dicarboxylates such as succinate are the sole carbon source. This growth lag is regulated in part by RpoS, the RssB antiadaptor IraP, translation elongation factor P, and to a lesser degree the stringent response. We also show that small amounts of proline or citrate can trigger early growth in succinate medium and that, at least for proline, this effect requires the multifunctional enzyme/regulator PutA. We demonstrate that activation of RpoS results in the repression of dctA, encoding the primary dicarboxylate importer, and that constitutive expression of dctA induces growth. This dicarboxylate growth lag phenotype is far more severe across multiple Salmonella isolates than it is in its close relative Escherichia coli. Replacing 200 nucleotides of the Salmonella dctA promoter region with that of E. coli was sufficient to eliminate the observed lag in growth. We hypothesized that this cis-regulatory divergence might be an adaptation to Salmonella’s virulent lifestyle, where levels of phagocyte-produced succinate increase in response to bacterial LPS; however, we found that impairing dctA repression had no effect on Salmonella’s survival in acidified succinate or in macrophages. IMPORTANCE Bacteria have evolved to sense and respond to their environment to maximize their chance of survival. By studying differences in the responses of pathogenic bacteria and closely related nonpathogens, we can gain insight into what environments they encounter inside of an infected host. Here, we demonstrate that Salmonella diverges from its close relative E. coli in its response to dicarboxylates such as the metabolite succinate. We show that this is regulated by stress response proteins and ultimately can be attributed to Salmonella repressing its import of dicarboxylates. Understanding this phenomenon may reveal a novel aspect of the Salmonella virulence cycle, and our characterization of its regulation yields a number of mutant strains that can be used to further study it.

scholarly journals Lactobacillus rhamnosus L34 Attenuates Gut Translocation-Induced Bacterial Sepsis in Murine Models of Leaky Gut

2017 ◽  
Vol 86 (1) ◽  
Author(s):  
Wimonrat Panpetch ◽  
Wiwat Chancharoenthana ◽  
Kanthika Bootdee ◽  
Sumanee Nilgate ◽  
Malcolm Finkelman ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Lactobacillus Rhamnosus ◽  
Fluorescein Isothiocyanate ◽  
Therapeutic Effects ◽  
Content Type ◽  
Antibiotic Cocktail ◽  
Sepsis Model ◽  
Serovar Typhimurium

ABSTRACT Gastrointestinal (GI) bacterial translocation in sepsis is well known, but the role of Lactobacillus species probiotics is still controversial. We evaluated the therapeutic effects of Lactobacillus rhamnosus L34 in a new sepsis model of oral administration of pathogenic bacteria with GI leakage induced by either an antibiotic cocktail (ATB) and/or dextran sulfate sodium (DSS). GI leakage with ATB, DSS, and DSS plus ATB (DSS+ATB) was demonstrated by fluorescein isothiocyanate (FITC)-dextran translocation to the circulation. The administration of pathogenic bacteria, either Klebsiella pneumoniae or Salmonella enterica serovar Typhimurium, enhanced translocation. Bacteremia was demonstrated within 24 h in 50 to 88% of mice with GI leakage plus the administration of pathogenic bacteria but not with GI leakage induction alone or bacterial gavage alone. Salmonella bacteremia was found in only 16 to 29% and 0% of mice with Salmonella and Klebsiella administrations, respectively. Klebsiella bacteremia was demonstrated in 25 to 33% and 10 to 16% of mice with Klebsiella and Salmonella administrations, respectively. Lactobacillus rhamnosus L34 attenuated GI leakage in these models, as shown by the reductions of FITC-dextran gut translocation, serum interleukin-6 (IL-6) levels, bacteremia, and sepsis mortality. The reduction in the amount of fecal Salmonella bacteria with Lactobacillus treatment was demonstrated. In addition, an anti-inflammatory effect of the conditioned medium from Lactobacillus rhamnosus L34 was also demonstrated by the attenuation of cytokine production in colonic epithelial cells in vitro. In conclusion, Lactobacillus rhamnosus L34 attenuated the severity of symptoms in a murine sepsis model induced by GI leakage and the administration of pathogenic bacteria.

scholarly journals Mapping and Regulation of Genes within Salmonella Pathogenicity Island 12 That Contribute toIn VivoFitness of Salmonella enterica Serovar Typhimurium

2013 ◽  
Vol 81 (7) ◽  
pp. 2394-2404 ◽  
Author(s):  
Ana M. Tomljenovic-Berube ◽  
Brandyn Henriksbo ◽  
Steffen Porwollik ◽  
Colin A. Cooper ◽  
Brian R. Tuinema ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Pathogenicity Island ◽  
Bacterial Survival ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Serovar Typhimurium ◽  
Bacterial Fitness ◽  
Virulence Regulator

ABSTRACTSalmonellapathogenicity island 12 (SPI-12) ofSalmonella entericaserovar Typhimurium is a 15-kb region that encompasses genesSTM2230toSTM2245and encodes a remnant phage known to contribute to bacterial virulence. In mouse infection experiments and replication assays in macrophages, we demonstrated a role for four genes in SPI-12 for bacterial survival in the host. STM2239, a potential Q antiterminator, showed a prominent contribution to bacterial fitness. Transcriptional reporter experiments, quantitative reverse transcription-PCR (RT-PCR), and immunoblotting demonstrated that the virulence regulator SsrB and STM2239 contribute to transcriptional activation of genes in SPI-12. SsrB was found to indirectly regulate this locus by transcriptional read-through from thesspH2(STM2241) promoter. Chromatin immunoprecipitation showed that STM2239 copurified with the promoter regulatingSTM2237, suggesting that STM2239 may function as an antiterminator to activate adjacent genes. These results demonstrate that bacteriophage genes may be adapted by pathogenic bacteria to improve fitness in the host.

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