ABSTRACT Nosocomial infections caused by Staphylococcus epidermidis are characterized biofilm formation on implanted medical devices. Quorum-sensing regulation plays a major role in the development of many bacterial pathogens. Here, we describe luxS , quorum-sensing system staphylococci that has significant impact and virulence. We constructed an isogenic ΔluxS mutant strain biofilm-forming clinical isolate S. demonstrated signaling is functional . The showed increased vitro enhanced...

Yersinia pestis, the agent of plague, is transmitted to mammals by infected fleas. Y. pestis exhibits a distinct life stage in flea, where it grows form cohesive biofilm that promotes transmission. After transmission, temperature shift 37°C induces many known virulence factors confer resistance innate immunity. These are not produced low-temperature environment however, suggesting vulnerable initial encounter with immune cells at flea bite site. In this study, we used whole-genome...

Strains of the food-borne pathogen Listeria monocytogenes, showing either intermediate or high-level resistance to class IIa bacteriocins, were investigated determine characteristics that correlated with their sensitivity levels. Two and one highly resistant spontaneous mutant L. monocytogenes B73, a 412, resistant, defined (mptA) EGDe compared respective wild-type strains in order investigate contribution different factors resistance. Decreased mannose-specific phosphotransferase system...

ABSTRACT A major concern in the use of class IIa bacteriocins as food preservatives is well-documented resistance development target Listeria strains. We studied relationship between leucocin A, a bacteriocin, and composition phospholipid, phosphatidylglycerol (PG), membranes both sensitive resistant L. monocytogenes Two wild-type strains, B73 412, two spontaneous mutants with intermediate to (±2.4 ±4 times 50% inhibitory concentrations [IC 50 ] for strains), highly each strains (>500 IC...

Abstract Background Autoinducer 2 (AI-2), a widespread by-product of the LuxS-catalyzed S-ribosylhomocysteine cleavage reaction in activated methyl cycle, has been suggested to serve as an intra- and interspecies signaling molecule, but many bacteria AI-2 control gene expression is not completely understood. Particularly, we have lack knowledge about important human pathogens Staphylococcus aureus S. epidermidis . Results To determine role LuxS , analyzed genome-wide changes luxS mutant...

The Yersinia pestis PhoPQ gene regulatory system is induced during infection of the flea digestive tract and required to produce adherent biofilm in foregut, which greatly enhances bacterial transmission a bite. To understand vivo context induction determine PhoP-regulated targets flea, we undertook whole-genome comparative transcriptional profiling Y. WT ΔphoP strains isolated from infected fleas temperature-matched vitro planktonic flow-cell cultures. In absence PhoP regulation, expression...

Significance Transition metals are required for proper cellular function, which renders them critical all life. To restrict bacterial infection, eukaryotic organisms actively sequester these transition metals, a concept referred to as nutritional immunity. Consequently, pathogens have evolved dedicated mechanisms acquire in order colonize the host. During human plague, Yersinia pestis overcomes iron limitation via production of secreted siderophore yersiniabactin. Here, we identify an...

Yersinia pestis diverged from pseudotuberculosis</= 20 000 years ago, during which time it evolved to be transmitted by fleas. In comparing the ability of these closely related species infect rat flea Xenopsylla cheopis, we found that Y. pseudotuberculosis, unlike pestis, is orally toxic Fleas showed signs acute toxicity, including diarrhoea, immediately after feeding on blood containing pseudotuberculosis in response protein toxin(s) produced bacteria. Adherence midgut and large...

The plague bacillus Yersinia pestis can achieve transmission by biofilm blockage of the foregut proventriculus its flea vector. Hfq is revealed to be essential for formation and acquisition fitness Y. during gut infection, consistent with posttranscriptional regulatory mechanisms in transmission.

Plague is a flea-borne rodent-associated zoonotic disease caused by Yersinia pestis The characterized epizootics with high rodent mortalities, punctuated interepizootic periods when the bacterium persists in an unknown reservoir. This study investigates interaction between Y. and ubiquitous soil free-living amoeba (FLA) Acanthamoeba castellanii to assess if can survive within amoebae whether intracellular mechanisms are conserved infection of mammalian macrophages amoebae. results...

High-level resistance to class IIa bacteriocins has been directly associated with the absent EIIAB Man (MptA) subunit of mannose-specific phosphoenolpyruvate-dependent phosphotransferase system (PTS) ( ) in Listeria monocytogenes strains. Class bacteriocin-resistant strains used this study were a spontaneous resistant, L. B73-MR1, and defined mutant, EGDe- mptA . Both previously reported have PTS component missing. This shows that these significantly decreased specific growth glucose...

Summary The second messenger molecule cyclic diguanylate is essential for Y ersinia pestis biofilm formation that important blockage‐dependent plague transmission from fleas to mammals. Two cyclases ( DGCs ) HmsT and 3730 HmsD are responsible in vitro biofilm‐dependent blockage the oriental rat flea X enopsylla cheopis respectively. Here, we have identified a tripartite signalling system encoded by y3729‐y3731 operon regulation of different environments. We present genetic evidence putative...

Yersinia pestis has evolved as a clonal variant of pseudotuberculosis to cause flea-borne biofilm-mediated transmission the bubonic plague. The LysR-type transcriptional regulator, RovM, is highly induced only during Y. infection flea host. RovM homologs in other pathogens regulate biofilm formation, nutrient sensing, and virulence; including pseudotuberculosis, where represses major virulence factor, RovA. Here role that plays was investigated using KIM6+ strain deleted rovM, ΔrovM. ΔrovM...

While alternating between insects and mammals during its life cycle, Yersinia pestis, the flea-transmitted bacterium that causes plague, regulates gene expression appropriately to adapt these two physiologically disparate host environments. In fleas competent transmit Y. low-GC-content genes y3555, y3551, y3550 are highly transcribed, suggesting have a prioritized role in flea infection. Here, we demonstrate transcribed as part of single polycistronic mRNA comprising y3554, y3553, y355x,...

ABSTRACT Yersinia pestis , the causative agent of plague, evolved from closely related pathogen pseudotuberculosis . During its emergence, Y. is believed to have acquired unique pathogenic characteristics through numerous gene gains/losses, genomic rearrangements, and single nucleotide polymorphism (SNP) changes. One such SNP creates a amino acid variation in DNA binding domain PhoP, response regulator PhoP/PhoQ two-component system. basal human-avirulent strains harbor glycines at position...

Multiple genetic changes in the enteric pathogen

Yersinia pseudotuberculosis is a foodborne enteric pathogen that causes mild self-limiting diarrhea in humans. able to persist soil and water association with fresh produce, but the mechanism by which it persists unknown. It has been shown Y. co-occurs protozoans these environments; therefore, this study investigates if bacterivorous free-living amoeba (FLA) are support persistence of pseudotuberculosis. Coculture studies prototype FLA, Acanthamoeba castellanii revealed bacteria had an...

Plague-causing Yersinia pestis is transmitted through regurgitation when it forms a biofilm-mediated blockage in the foregut of its flea vector. This biofilm composed an extracellular polysaccharide substance (EPS) produced cyclic-di-GMP (c-di-GMP) levels are elevated. The Y. diguanylate cyclase enzymes HmsD and HmsT synthesize c-di-GMP. required for formation but contributes minimally to vitro biofilms. HmsT, however, necessary biofilms intermediate rates blockage. C-di-GMP synthesis...

Abstract Plague, caused by the flea-transmitted bacterial pathogen Yersinia pestis, is primarily a disease of wild rodents distributed in temperate and tropical zones worldwide. The ability Y. pestis to develop biofilm blockage that obstructs flea foregut proventriculus facilitates its efficient transmission through regurgitation into host bite site during blood sucking. While it known temperature influences transmission, not well-known if dynamics are similarly accord with temperature....