Salmonella enterica Serovar Typhimurium Swarming Mutants with Altered Biofilm-Forming Abilities: Surfactin Inhibits Biofilm Formation

ABSTRACT Swarming motility plays an important role in surface colonization by several flagellated bacteria. Swarmer cells are specially adapted to rapidly translocate over agar surfaces by virtue of their more numerous flagella, longer cell length, and encasement of slime. The external slime provides the milieu for motility and likely harbors swarming signals. We recently reported the isolation of swarming-defective transposon mutants of Salmonella enterica serovar Typhimurium, a large majority of which were defective in lipopolysaccharide (LPS) synthesis. Here, we have examined the biofilm-forming abilities of the swarming mutants using a microtiter plate assay. A whole spectrum of efficiencies were observed, with LPS mutants being generally more proficient than wild-type organisms in biofilm formation. Since we have postulated that O-antigen may serve a surfactant function during swarming, we tested the effect of the biosurfactant surfactin on biofilm formation. We report that surfactin inhibits biofilm formation of wild-type S. enterica grown either in polyvinyl chloride microtiter wells or in urethral catheters. Other bio- and chemical surfactants tested had similar effects.

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Biofilm Formation by Psychrobacter arcticus and the Role of a Large Adhesin in Attachment to Surfaces

Applied and Environmental Microbiology ◽

10.1128/aem.00867-13 ◽

2013 ◽

Vol 79 (13) ◽

pp. 3967-3973 ◽

Cited By ~ 10

Author(s):

Shannon M. Hinsa-Leasure ◽

Cassandra Koid ◽

James M. Tiedje ◽

Janna N. Schultzhaus

Keyword(s):

Biofilm Formation ◽

Time Course ◽

Microtiter Plate ◽

Bacterial Attachment ◽

Wild Type ◽

Microtiter Plate Assay ◽

Content Type ◽

Reading Frame ◽

Transposon Mutants

ABSTRACTPsychrobacter arcticusstrain 273-4, an isolate from a Siberian permafrost core, is capable of forming biofilms when grown in minimal medium under laboratory conditions. Biofilms form at 4 to 22°C when acetate is supplied as the lone carbon source and with 1 to 7% sea salt.P. arcticusis also capable of colonizing quartz sand. Transposon mutagenesis identified a gene important for biofilm formation byP. arcticus. Four transposon mutants were mapped to a 20.1-kbp gene, which is predicted to encode a protein of 6,715 amino acids (Psyc_1601). We refer to this open reading frame ascat1, for cold attachment gene 1. Thecat1mutants are unable to form biofilms at levels equivalent to that of the wild type, and there is no impact on the planktonic growth characteristics of the strains, indicating a specific role in biofilm formation. Through time course studies of the static microtiter plate assay, we determined thatcat1mutants are unable to form biofilms equivalent to that of the wild type under all conditions tested. In flow cell experiments,cat1mutants initially are unable to attach to the surface. Over time, however, they form microcolonies, an architecture very different from that produced by wild-type biofilms. Our results demonstrate that Cat1 is involved in the initial stages of bacterial attachment to surfaces.

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A network of Rab GTPases controls phagosome maturation and is modulated by Salmonella enterica serovar Typhimurium

The Journal of Cell Biology ◽

10.1083/jcb.200611056 ◽

2007 ◽

Vol 176 (3) ◽

pp. 263-268 ◽

Cited By ~ 107

Author(s):

Adam C. Smith ◽

Won Do Heo ◽

Virginie Braun ◽

Xiuju Jiang ◽

Chloe Macrae ◽

...

Keyword(s):

Salmonella Enterica ◽

Salmonella Enterica Serovar Typhimurium ◽

Dominant Negative ◽

Rab Gtpases ◽

Wild Type ◽

Intracellular Growth ◽

Non Invasive ◽

Serovar Typhimurium ◽

Guanosine Triphosphatase ◽

Kinetics Of

Members of the Rab guanosine triphosphatase (GTPase) family are key regulators of membrane traffic. Here we examined the association of 48 Rabs with model phagosomes containing a non-invasive mutant of Salmonella enterica serovar Typhimurium (S. Typhimurium). This mutant traffics to lysosomes and allowed us to determine which Rabs localize to a maturing phagosome. In total, 18 Rabs associated with maturing phagosomes, each with its own kinetics of association. Dominant-negative mutants of Rab23 and 35 inhibited phagosome–lysosome fusion. A large number of Rab GTPases localized to wild-type Salmonella-containing vacuoles (SCVs), which do not fuse with lysosomes. However, some Rabs (8B, 13, 23, 32, and 35) were excluded from wild-type SCVs whereas others (5A, 5B, 5C, 7A, 11A, and 11B) were enriched on this compartment. Our studies demonstrate that a complex network of Rab GTPases controls endocytic progression to lysosomes and that this is modulated by S. Typhimurium to allow its intracellular growth.

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Salmonella enterica Serovar Typhimurium Uses PbgA/YejM To Regulate Lipopolysaccharide Assembly during Bacteremia

Infection and Immunity ◽

10.1128/iai.00758-19 ◽

2019 ◽

Vol 88 (1) ◽

Cited By ~ 16

Author(s):

Melina B. Cian ◽

Nicole P. Giordano ◽

Revathi Masilamani ◽

Keaton E. Minor ◽

Zachary D. Dalebroux

Keyword(s):

Salmonella Enterica ◽

Lipid A ◽

Salmonella Enterica Serovar Typhimurium ◽

Transmembrane Domain ◽

Wild Type ◽

Content Type ◽

Serovar Typhimurium ◽

Periplasmic Domain ◽

Inner Membrane Protein ◽

Substitution Mutations

ABSTRACT Salmonella enterica serovar Typhimurium (S. Typhimurium) relies upon the inner membrane protein PbgA to enhance outer membrane (OM) integrity and promote virulence in mice. The PbgA transmembrane domain (residues 1 to 190) is essential for viability, while the periplasmic domain (residues 191 to 586) is dispensable. Residues within the basic region (residues 191 to 245) bind acidic phosphates on polar phospholipids, like for cardiolipins, and are necessary for salmonella OM integrity. S. Typhimurium bacteria increase their OM cardiolipin concentrations during activation of the PhoPQ regulators. The mechanism involves PbgA’s periplasmic globular region (residues 245 to 586), but the biological role of increasing cardiolipins on the surface is not understood. Nonsynonymous polymorphisms in three essential lipopolysaccharide (LPS) synthesis regulators, lapB (also known as yciM), ftsH, and lpxC, variably suppressed the defects in OM integrity, rifampin resistance, survival in macrophages, and systemic colonization of mice in the pbgAΔ191–586 mutant (in which the PbgA periplasmic domain from residues 191 to 586 is deleted). Compared to the OMs of the wild-type salmonellae, the OMs of the pbgA mutants had increased levels of lipid A-core molecules, cardiolipins, and phosphatidylethanolamines and decreased levels of specific phospholipids with cyclopropanated fatty acids. Complementation and substitution mutations in LapB and LpxC generally restored the phospholipid and LPS assembly defects for the pbgA mutants. During bacteremia, mice infected with the pbgA mutants survived and cleared the bacteria, while animals infected with wild-type salmonellae succumbed within 1 week. Remarkably, wild-type mice survived asymptomatically with pbgA-lpxC salmonellae in their livers and spleens for months, but Toll-like receptor 4-deficient animals succumbed to these infections within roughly 1 week. In summary, S. Typhimurium uses PbgA to influence LPS assembly during stress in order to survive, adapt, and proliferate within the host environment.

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The RcsCDB Signaling System and Swarming Motility in Salmonella enterica Serovar Typhimurium: Dual Regulation of Flagellar and SPI-2 Virulence Genes

Journal of Bacteriology ◽

10.1128/jb.01198-07 ◽

2007 ◽

Vol 189 (23) ◽

pp. 8447-8457 ◽

Cited By ~ 90

Author(s):

Qingfeng Wang ◽

Yifang Zhao ◽

Michael McClelland ◽

Rasika M. Harshey

Keyword(s):

Salmonella Enterica ◽

Target Genes ◽

Salmonella Enterica Serovar Typhimurium ◽

Acid Synthesis ◽

Signaling System ◽

Swarming Motility ◽

Colanic Acid ◽

Serovar Typhimurium ◽

Type 3 ◽

Regulatory Properties

ABSTRACT The Rcs phosphorelay is a multicomponent signaling system that positively regulates colanic acid synthesis and negatively regulates motility and virulence. We have exploited a spontaneously isolated mutant, IgaA(T191P), that is nearly maximally activated for the Rcs system to identify a vast set of genes that respond to the stimulation, and we report new regulatory properties of this signaling system in Salmonella enterica serovar Typhimurium. Microarray data show that the Rcs system normally functions as a positive regulator of SPI-2 and other genes important for the growth of Salmonella in macrophages, although when highly activated the system completely represses the SPI-1/SPI-2 virulence, flagellar, and fimbrial biogenesis pathways. The auxiliary protein RcsA, which works with RcsB to positively regulate colanic acid and other target genes, not only stimulates but also antagonizes the positive regulation of many genes in the igaA mutant. We show that RcsB represses motility through the RcsB box in the promoter region of the master operon flhDC and that RcsA is not required for this regulation. Curiously, RcsB selectively stimulates expression of the flagellar type 3 secretion genes fliPQR; an RcsAB box located downstream of fliR influences this regulation. We show that excess colanic acid impairs swimming and inhibits swarming motility, consistent with the inverse regulation of the two pathways by the Rcs system.

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A Plasmid-Encoded FetMP-Fls Iron Uptake System Confers Selective Advantages to Salmonella enterica Serovar Typhimurium in Growth under Iron-Restricted Conditions and for Infection of Mammalian Host Cells

Microorganisms ◽

10.3390/microorganisms8050630 ◽

2020 ◽

Vol 8 (5) ◽

pp. 630

Author(s):

Vanesa García ◽

Ana Herrero-Fresno ◽

Rosaura Rodicio ◽

Alfonso Felipe-López ◽

Ignacio Montero ◽

...

Keyword(s):

Iron Content ◽

Salmonella Enterica ◽

Iron Uptake ◽

Type Strain ◽

Wild Type Strain ◽

Salmonella Enterica Serovar Typhimurium ◽

Iron Acquisition ◽

Clinical Strain ◽

Wild Type ◽

Serovar Typhimurium

The resistance plasmid pUO-StVR2, derived from virulence plasmid pSLT, is widespread in clinical isolates of Salmonella enterica serovar Typhimurium recovered in Spain and other European countries. pUO-StVR2 carries several genes encoding a FetMP-Fls system, which could be involved in iron uptake. We therefore analyzed S. Typhimurium LSP 146/02, a clinical strain selected as representative of the isolates carrying the plasmid, and an otherwise isogenic mutant lacking four genes (fetMP-flsDA) of the fetMP-fls region. Growth curves and determination of the intracellular iron content under iron-restricted conditions demonstrated that deletion of these genes impairs iron acquisition. Thus, under these conditions, the mutant grew significantly worse than the wild-type strain, its iron content was significantly lower, and it was outcompeted by the wild-type strain in competition assays. Importantly, the strain lacking the fetMP-flsDA genes was less invasive in cultured epithelial HeLa cells and replicated poorly upon infection of RAW264.7 macrophages. The genes were introduced into S. Typhimurium ATCC 14028, which lacks the FetMP-Fls system, and this resulted in increased growth under iron limitation as well as an increased ability to multiply inside macrophages. These findings indicate that the FetMP-Fls iron acquisition system exceeds the benefits conferred by the other high-affinity iron uptake systems carried by ATCC 14028 and LSP 146/02. We proposed that effective iron acquisition by this system in conjunction with antimicrobial resistance encoded from the same plasmid have greatly contributed to the epidemic success of S. Typhimurium isolates harboring pUO-StVR2.

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The small regulatory RNA molecule MicA is involved in Salmonella enterica serovar Typhimurium biofilm formation

BMC Microbiology ◽

10.1186/1471-2180-10-276 ◽

2010 ◽

Vol 10 (1) ◽

pp. 276 ◽

Cited By ~ 33

Author(s):

Gwendoline Kint ◽

David De Coster ◽

Kathleen Marchal ◽

Jos Vanderleyden ◽

Sigrid CJ De Keersmaecker

Keyword(s):

Salmonella Enterica ◽

Biofilm Formation ◽

Salmonella Enterica Serovar Typhimurium ◽

Regulatory Rna ◽

Small Regulatory Rna ◽

Serovar Typhimurium

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Salicylic acid-based poly(anhydride esters) for control of biofilm formation in Salmonella enterica serovar Typhimurium

Letters in Applied Microbiology ◽

10.1111/j.1472-765x.2008.02356.x ◽

2008 ◽

Vol 46 (5) ◽

pp. 593-599 ◽

Cited By ~ 51

Author(s):

L.E. Rosenberg ◽

A.L. Carbone ◽

U. Römling ◽

K.E. Uhrich ◽

M.L. Chikindas

Keyword(s):

Salicylic Acid ◽

Salmonella Enterica ◽

Biofilm Formation ◽

Salmonella Enterica Serovar Typhimurium ◽

Serovar Typhimurium

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Biofilm Formation by Salmonella enterica Serovar Typhimurium and Escherichia coli on Epithelial Cells following Mixed Inoculations

Infection and Immunity ◽

10.1128/iai.73.8.5198-5203.2005 ◽

2005 ◽

Vol 73 (8) ◽

pp. 5198-5203 ◽

Cited By ~ 15

Author(s):

Cristina L. C. Esteves ◽

Bradley D. Jones ◽

Steven Clegg

Keyword(s):

Escherichia Coli ◽

Epithelial Cells ◽

Salmonella Enterica ◽

Biofilm Formation ◽

Salmonella Enterica Serovar Typhimurium ◽

E Coli ◽

Serovar Typhimurium

ABSTRACT Biofilms were formed by inoculations of Salmonella enterica serovar Typhimurium and Escherichia coli on HEp-2 cells. Inoculations of S. enterica serovar Typhimurium and E. coli resulted in the formation of an extensive biofilm of S. enterica serovar Typhimurium. In experiments where an E. coli biofilm was first formed followed by challenge with S. enterica serovar Typhimurium, there was significant biofilm formation by S. enterica serovar Typhimurium. The results of this study indicate that S. enterica serovar Typhimurium can outgrow E. coli in heterologous infections and displace E. coli when it forms a biofilm on HEp-2 cells.

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