Bile salts regulate zinc uptake and capsule synthesis in a mastitis-associated extraintestinal pathogenic Escherichia coli strain

2021 ◽  
Author(s):  
Michael A. Olson ◽  
Aleksander Grimsrud ◽  
Amanda C. Richards ◽  
Matthew A. Mulvey ◽  
Eric Wilson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bile Salts ◽  
Bloodstream Infections ◽  
Mouse Mammary Gland ◽  
Coli Strain ◽  
Zinc Uptake ◽  
Zinc Homeostasis ◽  
Growth Delay ◽  
Capsule Production

Extraintestinal pathogenic Escherichia coli (ExPEC) are major causes of urinary and bloodstream infections. ExPEC reservoirs are not completely understood. Some mastitis-associated E. coli (MAEC) strains carry genes associated with ExPEC virulence, including metal scavenging, immune avoidance, and host attachment functions. In this study, we investigated the role of the high-affinity zinc uptake ( znuABC ) system in the MAEC strain M12. Elimination of znuABC moderately decreased fitness during mouse mammary gland infections. The Δ znuABC mutant strain exhibited an unexpected growth delay in the presence of bile salts, which was alleviated by the addition of excess zinc. We isolated Δ znuABC mutant suppressor mutants with improved growth of in bile salts, several of which no longer produced the K96 capsule made by strain M12. Addition of bile salts also reduced capsule production by strain M12 and ExPEC strain CP9, suggesting that capsule synthesis may be detrimental when bile salts are present. To better understand the role of the capsule, we compared the virulence of mastitis strain M12 with its unencapsulated Δ kpsCS mutant in two models of ExPEC disease. The wild type strain successfully colonized mouse bladders and kidneys and was highly virulent in intraperitoneal infections. Conversely, the Δ kpsCS mutant was unable to colonize kidneys and was unable to cause sepsis. These results demonstrate that some MAEC may be capable of causing human ExPEC illness. Virulence of strain M12 in these infections is dependent on its capsule. However, capsule may interfere with zinc homeostasis in the presence of bile salts while in the digestive tract.

scholarly journals A link between zinc uptake, bile salts, and a capsule required for virulence of a mastitis-associated extraintestinal pathogenic Escherichia coli strain

2020 ◽  
Author(s):  
Michael A. Olson ◽  
Aleksander Grimsrud ◽  
Amanda C. Richards ◽  
Matthew A. Mulvey ◽  
Eric Wilson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bile Salts ◽  
Bloodstream Infections ◽  
Mouse Mammary Gland ◽  
Coli Strain ◽  
Zinc Uptake ◽  
Zinc Homeostasis ◽  
Growth Delay ◽  
Capsule Production

ABSTRACTExtraintestinal pathogenic Escherichia coli (ExPEC) are major causes of urinary and bloodstream infections. ExPEC reservoirs are not completely understood. Some mastitis-associated E. coli (MAEC) strains carry genes associated with ExPEC virulence, including metal scavenging, immune avoidance, and host attachment functions. In this study, we investigated the role of the high-affinity zinc uptake (znuABC) system in the MAEC strain M12. Elimination of znuABC moderately decreased fitness during mouse mammary gland infections. The ΔznuABC mutant strain exhibited an unexpected growth delay in the presence of bile salts, which was alleviated by the addition of excess zinc. We isolated ΔznuABC mutant suppressor mutants with improved growth of in bile salts, several of which no longer produced the K96 capsule made by strain M12. Addition of bile salts also reduced capsule production by strain M12 and ExPEC strain CP9, suggesting that capsule synthesis may be detrimental when bile salts are present. To better understand the role of the capsule, we compared the virulence of mastitis strain M12 with its unencapsulated ΔkpsCS mutant in two models of ExPEC disease. The wild type strain successfully colonized mouse bladders and kidneys and was highly virulent in intraperitoneal infections. Conversely, the ΔkpsCS mutant was unable to colonize kidneys and was unable to cause sepsis. These results demonstrate that some MAEC may be capable of causing human ExPEC illness. Virulence of strain M12 in these infections is dependent on its capsule. However, capsule may interfere with zinc homeostasis in the presence of bile salts while in the digestive tract.

scholarly journals Dissection of the Role of Pili and Type 2 and 3 Secretion Systems in Adherence and Biofilm Formation of an Atypical Enteropathogenic Escherichia coli Strain

2013 ◽  
Vol 81 (10) ◽  
pp. 3793-3802 ◽  
Author(s):  
Rodrigo T. Hernandes ◽  
Miguel A. De la Cruz ◽  
Denise Yamamoto ◽  
Jorge A. Girón ◽  
Tânia A. T. Gomes
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Coli Strain ◽  
Mass Spectrometry Analysis ◽  
Secretion Systems ◽  
Content Type ◽  
Spectrometry Analysis ◽  
Rigid Rod

ABSTRACTAtypical enteropathogenicEscherichia coli(aEPEC) strains are diarrheal pathogens that lack bundle-forming pilus production but possess the virulence-associated locus of enterocyte effacement. aEPEC strain 1551-2 produces localized adherence (LA) on HeLa cells; however, its isogenic intimin (eae) mutant produces a diffuse-adherence (DA) pattern. In this study, we aimed to identify the DA-associated adhesin of the 1551-2eaemutant. Electron microscopy of 1551-2 identified rigid rod-like pili composed of an 18-kDa protein, which was identified as the major pilin subunit of type 1 pilus (T1P) by mass spectrometry analysis. Deletion offimAin 1551-2 affected biofilm formation but had no effect on adherence properties. Analysis of secreted proteins in supernatants of this strain identified a 150-kDa protein corresponding to SslE, a type 2 secreted protein that was recently reported to be involved in biofilm formation of rabbit and human EPEC strains. However, neither adherence nor biofilm formation was affected in a 1551-2sslEmutant. We then investigated the role of the EspA filament associated with the type 3 secretion system (T3SS) in DA by generating a doubleeae espAmutant. This strain was no longer adherent, strongly suggesting that the T3SS translocon is the DA adhesin. In agreement with these results, specific anti-EspA antibodies blocked adherence of the 1551-2eaemutant. Our data support a role for intimin in LA, for the T3SS translocon in DA, and for T1P in biofilm formation, all of which may act in concert to facilitate host intestinal colonization by aEPEC strains.

scholarly journals Absolute requirement for polyamines for growth of Escherichia coli mutants (mnmE/G) defective in modification of the wobble anticodon of transfer-RNA

2019 ◽  
Vol 366 (10) ◽  
Author(s):  
Christopher Keller ◽  
Manas Chattopadhyay ◽  
Herbert Tabor
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Protein Biosynthesis ◽  
Transfer Rna ◽  
Coli Strain ◽  
E Coli ◽  
Wobble Position ◽  
Inhibition Of Growth ◽  
Absolute Requirement

Abstract The genes mnmE and mnmG are responsible for the modification of uridine 34, ‘the wobble position’ of many aminoacyl-tRNAs. Deletion of these genes affects the strength of the codon-anticodon interactions of the aminoacyl-tRNAs with the mRNAs and the ribosomes. However, deletion of these genes does not usually have a significant effect on the growth rate of the standard Escherichia coli strains. In contrast, we have found that if the host E. coli strain is deficient in the synthesis of polyamines, deletion of the mnmE or mnmG gene results in complete inhibition of growth unless the medium contains polyamines. The finding of an absolute requirement for polyamines in our current work will be significant in studies on polyamine function, in studies on the function of the mnmE/G genes, and in studies on the role of aminoacyl-tRNAs in protein biosynthesis.

scholarly journals Defining the Role of theStreptococcus agalactiaeSht-Family Proteins in Zinc Acquisition and Complement Evasion

2019 ◽  
Vol 201 (8) ◽  
Author(s):  
P. Moulin ◽  
V. Rong ◽  
A. Ribeiro E Silva ◽  
V. G. Pederick ◽  
E. Camiade ◽  
...  
Keyword(s):  
Human Blood ◽  
Streptococcus Agalactiae ◽  
Metal Ion ◽  
Binding Proteins ◽  
Factor H ◽  
Zinc Uptake ◽  
Zinc Homeostasis ◽  
Content Type

ABSTRACTStreptococcus agalactiaeis not only part of the human intestinal and urogenital microbiota but is also a leading cause of septicemia and meningitis in neonates. Its ability to cause disease depends upon the acquisition of nutrients from its environment, including the transition metal ion zinc. The primary zinc acquisition system of the pathogen is the Adc/Lmb ABC permease, which is essential for viability in zinc-restricted environments. Here, we show that in addition to the AdcCB transporter and the three zinc-binding proteins, Lmb, AdcA, and AdcAII,S. agalactiaezinc homeostasis also involves two streptococcal histidine triad (Sht) proteins. Sht and ShtII are required for zinc uptake via the Lmb and AdcAII proteins with apparent overlapping functionality and specificity. Both Sht-family proteins possess five-histidine triad motifs with similar hierarchies of importance for Zn homeostasis. Independent of its contribution to zinc homeostasis, Sht has previously been reported to bind factor H leading to predictions of a contribution to complement evasion. Here, we investigated ShtII to ascertain whether it had similar properties. Analysis of recombinant Sht and ShtII reveals that both proteins have similar affinities for factor H binding. However, neither protein aided in resistance to complement in human blood. These findings challenge prior inferences regarding thein vivorole of the Sht proteins in resisting complement‐mediated clearance.IMPORTANCEThis study examined the role of the two streptococcal histidine triad (Sht) proteins ofStreptococcus agalactiaein zinc homeostasis and complement resistance. We showed that Sht and ShtII facilitate zinc homeostasis in conjunction with the metal-binding proteins Lmb and AdcAII. Here, we show that the Sht-family proteins are functionally redundant with overlapping roles in zinc uptake. Further, this work reveals that although the Sht-family proteins bind to factor Hin vitrothis did not influence survival in human blood.

scholarly journals Inactivation of ibeA and ibeT Results in Decreased Expression of Type 1 Fimbriae in Extraintestinal Pathogenic Escherichia coli Strain BEN2908

2008 ◽  
Vol 76 (9) ◽  
pp. 4129-4136 ◽  
Author(s):  
Mélanie A. M. Cortes ◽  
Julien Gibon ◽  
Nathalie K. Chanteloup ◽  
Maryvonne Moulin-Schouleur ◽  
Philippe Gilot ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Wild Type Strain ◽  
Coli Strain ◽  
Wild Type ◽  
Adhesive Properties ◽  
Type 1 Fimbriae ◽  
Pathogenic Escherichia Coli ◽  
Genes Encoding

ABSTRACT IbeA in extraintestinal pathogenic Escherichia coli (ExPEC) strains was previously described for its role in invasion. Here we investigated the role of IbeA and IbeT, encoded by a gene located downstream of ibeA, in the adhesion of the avian ExPEC strain BEN2908 to human brain microvascular endothelial cells (HBMEC). The ΔibeA mutant was less adhesive to HBMEC than the wild-type strain BEN2908 was. Because strain BEN2908 also expresses type 1 fimbriae, we measured the adhesion specifically due to IbeA by comparing the adhesive properties of a Δfim derivative of strain BEN2908 to those of a double Δfim ΔibeA mutant. No differences were observed, indicating that the reduction of adhesion in BEN2908 ΔibeA could be due to a decrease in type 1 fimbria expression. We indeed showed that the decreased adhesion of BEN2908 ΔibeA was correlated with a decrease in type 1 fimbria expression. Accordingly, more bacteria had a fim promoter orientated in the off position in a culture of BEN2908 ΔibeA than in a culture of BEN2908. Expression of fimB and fimE, two genes encoding recombinases participating in controlling the orientation of the fim promoter, was decreased in BEN2908 ΔibeA. A reduction of type 1 fimbria expression due to a preferential orientation of the fim promoter in the off position was also seen in an ibeT mutant of strain BEN2908. We finally suggest a role for IbeA and IbeT in modulating the expression of type 1 fimbriae through an as yet unknown mechanism.

Sign in / Sign up

Export Citation Format

Share Document