Comparative Analysis of Chromosome-Encoded Microcins

Poey, María Eloisa; Azpiroz, Fernando; Laviña, Magela

doi:10.1128/aac.50.4.1411-1418.2006

Cited by 53 publications

(57 citation statements)

References 26 publications

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“…Previous reports have shown that these genes are often located on the same pathogenicity island (PAI) (12,16,19), and this would also explain our data. In addition, PAI-CFT073-serX contains the microcin M/H47 gene cluster, F1C fimbrial genes, and the iro gene cluster (4).…”

Section: Figsupporting

confidence: 77%

Molecular Characterization of Escherichia coli Strains That Cause Symptomatic and Asymptomatic Urinary Tract Infections

et al. 2012

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The differences between Escherichia coli strains associated with symptomatic and asymptomatic urinary tract infections (UTIs) remain to be properly determined. Here we examined the prevalence of plasmid types and bacteriocins, as well as genetic relatedness, in a defined collection of E. coli strains that cause UTIs. Comparative analysis identified a subgroup of strains with a high number of virulence genes (VGs) and microcins M/H47. We also identified associations between microcin genes, VGs, and specific plasmid types. U rinary tract infections (UTIs) are among the most common infectious diseases of humans (17). Uropathogenic Escherichia coli (UPEC) is the major etiological agent of UTIs and can cause both symptomatic infection and asymptomatic bacteriuria (ABU) in catheterized (CA-ABU) and noncatheterized patients with ABU. Two recent studies identified and compared the virulence gene (VG) carriage of E. coli strains isolated from patients with ABU, CA-ABU, and symptomatic UTIs (13, 21). However, the prevalence of plasmid types and bacteriocins and the genetic relatedness of these strains were not elucidated. Here we have examined these features in the same set of E. coli strains that cause UTIs by determining the prevalence of different plasmid incompatibility types and sequence types (STs), the distribution of colicin and microcin genes, and their random amplified polymorphic DNA (RAPD) profile.A collection of 159 UTI-causing E. coli strains consisting of 51 ABU, 62 CA-ABU, and 44 symptomatic UTI-causing strains (comprising 25 pyelonephritis and 19 cystitis strains) were used in this study (13,21). The ABU prototype strain 83972 (2, 11) and the ABU E. coli reference strain (ECOR) 71 were also used in this study. All strains have been previously characterized for the prevalence of 18 VGs and Clermont phylogenetic groups (13,21). These data were used for the comparative analysis with plasmid types and bacteriocins and RAPD analysis in this study. DNA extraction from the isolates was performed as previously described (1).Plasmid replicon typing was carried out to investigate the presence of 18 replicons using three multiplex panels (5, 8). The presence of the following 16 bacteriocins was assessed by multiplex PCRs: colicins A, B, D, E1, E2, E3, E6, E7, Ia/Ib, K, M, and V and microcins B17, H47, J25, and M. The PCR primers and pools are described in Table S1 in the supplemental material. The genetic relatedness of the UTI-causing strains was assessed by RAPD analysis using primer 1254 (CCGCAGCCAA) (14). The prevalence of the three most common STs (ST69, ST95, and ST131) associated with E. coli UTIs were also investigated using previously described methods (3, 7). Comparisons of prevalence among the different groups of E. coli were analyzed using the 2 test (n Ͼ 5) and Fisher's exact test (n Յ 5) using SPSS (version 17) software. The likelihood ratio 2 and Kappa () index was used to quantify the degree of coassociation between genes.Plasmid typing revealed 14 different plasmid replicons, with 84% of the strains...

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Section: Figsupporting

confidence: 77%

Molecular Characterization of Escherichia coli Strains That Cause Symptomatic and Asymptomatic Urinary Tract Infections

et al. 2012

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“…In addition to enterobactin synthesis, the modification requires genes of the iroA cluster for salmochelin synthesis, essentially iroB and iroD for glucosylation and backbone linearization, respectively. A similar posttranslational processing is anticipated for MccI47 and MccM (244,252). The modified microcins are recognized and taken up by the catecholate siderophore receptors FepA, Cir, and Fiu of E. coli and FepA, Cir, and IroN of S. enterica in a cooperative and TonB-dependent manner (77,244).…”

Section: "Trojan Horse" Antibioticsmentioning

confidence: 94%

Siderophore-Based Iron Acquisition and Pathogen Control

Miethke

Marahiel

2007

Microbiol Mol Biol Rev

1,420

1,302

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SUMMARY High-affinity iron acquisition is mediated by siderophore-dependent pathways in the majority of pathogenic and nonpathogenic bacteria and fungi. Considerable progress has been made in characterizing and understanding mechanisms of siderophore synthesis, secretion, iron scavenging, and siderophore-delivered iron uptake and its release. The regulation of siderophore pathways reveals multilayer networks at the transcriptional and posttranscriptional levels. Due to the key role of many siderophores during virulence, coevolution led to sophisticated strategies of siderophore neutralization by mammals and (re)utilization by bacterial pathogens. Surprisingly, hosts also developed essential siderophore-based iron delivery and cell conversion pathways, which are of interest for diagnostic and therapeutic studies. In the last decades, natural and synthetic compounds have gained attention as potential therapeutics for iron-dependent treatment of infections and further diseases. Promising results for pathogen inhibition were obtained with various siderophore-antibiotic conjugates acting as “Trojan horse” toxins and siderophore pathway inhibitors. In this article, general aspects of siderophore-mediated iron acquisition, recent findings regarding iron-related pathogen-host interactions, and current strategies for iron-dependent pathogen control will be reviewed. Further concepts including the inhibition of novel siderophore pathway targets are discussed.

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“…Microcins have a broad spectrum of bactericidal activity against Enterobacteriaceae, including Escherichia, Salmonella, Shigella, Citrobacter, Klebsiella, and Enterobacter (28,30). The synthesis of MccH47 is encoded by mchB within an ϳ10.5-kb mch47 operon (GenBank accession number AJ009631) (33). The mch47 peptide is synthesized as a 75-residue precursor that is processed during secretion to a 60-residue mature extracellular peptide of 4.9 kDa (36).…”

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Use of mchI Encoding Immunity to the Antimicrobial Peptide Microcin H47 as a Plasmid Selection Marker in Attenuated Bacterial Live Vectors

et al. 2008

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Live attenuated bacterial strains expressing heterologous antigens represent an attractive vaccine development strategy. However, the use of drug resistance genes for the selection of expression plasmids introduced into live vectors poses theoretical health risks. Therefore, we developed a novel approach for plasmid selection based on immunity to the antimicrobial peptide microcin H47 (MccH47). Two expression plasmids encoding the reporter green fluorescent protein (GFPuv) were constructed; selection markers comprised either mchI, conferring immunity to MccH47 (pGEN222I), or bla (encoding ␤-lactamase), conferring conventional resistance to ampicillin (pGEN222). GFPuv-specific serum immunoglobulin G (IgG) antibody responses were analyzed in mice immunized intranasally either with Salmonella enterica serovar Typhi CVD 908-htrA or Shigella flexneri 2a CVD 1208S live vector and were boosted parenterally with purified GFPuv. Similar IgG antibody responses were observed for both pGEN222 and pGEN222I when either CVD 1208S or CVD 908-htrA(pGEN222I) was used as the carrier. Interestingly, CVD 908-htrA(pGEN222I) elicited a significantly higher IgG response than CVD 908-htrA(pGEN222). We also compared the priming potential of homologous priming either with CVD 908-htrA(pGEN222I) or CVD 1208S(pGEN222I) to heterologous priming first with CVD 908-htrA(pGEN222I) and then with CVD 1208S(pGEN222I) and vice versa. Immunization with two unrelated live vectors significantly enhanced the IgG responses compared to responses engendered by homologous CVD 908-htrA(pGEN222I) but not to those of CVD 1208S(pGEN222I). MccH47 offers an alternate system for plasmid selection in bacterial live vectors that greatly improves their clinical acceptability. Furthermore, the success of the heterologous priming strategy supports the feasibility of the future development of multivalent live vector-based immunization strategies against multiple human pathogens.

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Comparative Analysis of Chromosome-Encoded Microcins

Cited by 53 publications

References 26 publications

Molecular Characterization of Escherichia coli Strains That Cause Symptomatic and Asymptomatic Urinary Tract Infections

Molecular Characterization of Escherichia coli Strains That Cause Symptomatic and Asymptomatic Urinary Tract Infections

Siderophore-Based Iron Acquisition and Pathogen Control

Use of mchI Encoding Immunity to the Antimicrobial Peptide Microcin H47 as a Plasmid Selection Marker in Attenuated Bacterial Live Vectors

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