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Polish Journal of Microbiology 2014Over the last decade, the growing number of multidrug resistant strains limits the use of many of the currently available chemotherapeutic agents. Furthermore, bacterial...
Over the last decade, the growing number of multidrug resistant strains limits the use of many of the currently available chemotherapeutic agents. Furthermore, bacterial biofilm, due to its complex structure, constitutes an effective barrier to conventional antibiotics. The in vitro activities of naturally occurring peptide (Citropin 1.1), chemically engineered analogue (Pexiganan), newly-designed, short amino-acid derivatives (Pal-KK-NH2, Pal-KKK-NH2, Pal-RRR-NH2) and six clinically used antimicrobial agents (Gatifloxacin, Ampicilin, Cefotaxime, Ceftriaxone, Cefuroxime and Cefalexin) were investigated against planktonic cells and mature biofilm of multidrug-resistant Providencia stuartii strains, isolated from urological catheters. The MICs, MBCs values were determined by broth microdilution technique. Inhibition of biofilm formation by antimicrobial agents as well as biofilm susceptibility assay were tested using a surrogate model based on the Crystal Violet method. The antimicrobial activity of amino-acids derivatives and synthetic peptides was compared to that of clinically used antibiotics. For planktonic cells, MICs of peptides and antibiotics ranged between 1 and 256 μg/ml and 256 and ≥ 2048 μg/ml, respectively. The MBCs values of Pexiganan, Citropin 1.1 and amino-acids derivatives were between 16 and 256 μg/ml, 64 and 256 μg/ml and 16 and 512 μg/ml, respectively. For clinically used antibiotics the MBCs values were above 2048 μg/ml. All of the tested peptides and amino-acids derivatives, showed inhibitory activity against P. stuartii biofilm formation, in relation to their concentrations. Pexiganan and Citropin 1.1 in concentration range 32 and 256 μg/ml caused both strong and complete suppression of biofilm formation. None of the antibiotics caused complete inhibition of biofilm formation process. The biofilm susceptibility assay verified the extremely poor antibiofilm activity of conventional antibiotics compared to synthetic peptides. The obtained results showed that synthetic peptides are generally more potent and effective than clinically used antibiotics.
Topics: Adult; Aged; Aged, 80 and over; Amino Acid Sequence; Amphibians; Animals; Anti-Bacterial Agents; Biofilms; Enterobacteriaceae Infections; Female; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Molecular Sequence Data; Peptides; Providencia
PubMed: 25804062
DOI: No ID Found -
FEMS Immunology and Medical Microbiology Dec 2012The O-polysaccharide chain of the lipopolysaccharide (O-antigen) on the bacterial cell surface is one of the most structurally variable cell components and serves as a...
The O-polysaccharide chain of the lipopolysaccharide (O-antigen) on the bacterial cell surface is one of the most structurally variable cell components and serves as a basis for serotyping of Gram-negative bacteria, including human opportunistic pathogens of the genus Providencia. In this work, the O-antigen of Providencia alcalifaciens O40 was obtained by mild acid degradation of the isolated lipopolysaccharide and studied by chemical methods and high-resolution NMR spectroscopy. The following structure of the O-polysaccharide was established: →4)-β-D-Quip3NFo-(1→3)-α-D-Galp-(1→3)-β-D-GlcpA-(1→3)-β-D-GalpNAc-(1→, where GlcA stands for glucuronic acid and Qui3NFo for 3,6-dideoxy-3-formamidoglucose. The O40-antigen was found to be structurally and serologically related to the O-antigens of P. alcalifaciens O5 and Providencia stuartii O18. The O40-antigen gene cluster between cpxA and yibK was sequenced, and the gene functions were predicted in silico. In agreement with the O-polysaccharide structure established, the genes for the synthesis of dTDP-D-Qui3NFo, UDP-D-Gal, UDP-D-GlcA, and UDP-D-GalNAc as well as those encoding three glycosyltransferases, flippase (Wzx), and O-antigen polymerase (Wzy) were recognized. In addition, homologues of wza, wzb, and wzc genes, which are required for the surface expression of capsular polysaccharides, were found within the gene cluster, suggesting that the O-polysaccharide studied is a part of the capsule-related form of the lipopolysaccharide called K(LPS).
Topics: Biosynthetic Pathways; DNA, Bacterial; Magnetic Resonance Spectroscopy; Molecular Sequence Data; Molecular Structure; Multigene Family; O Antigens; Providencia; Sequence Analysis, DNA
PubMed: 23163869
DOI: 10.1111/1574-695X.12002 -
The Journal of International Medical... Oct 2020To investigate the clinical and drug resistance characteristics of infections in the Huainan region of Anhui and provide a reference for the clinical selection of...
OBJECTIVES
To investigate the clinical and drug resistance characteristics of infections in the Huainan region of Anhui and provide a reference for the clinical selection of antimicrobial agents.
METHODS
This single-center retrospective analysis included 76 patients with infection in Huainan during the period from October 2018 to March 2020. The hospital department in which the patients were treated and the drug susceptibility characteristics of the isolates were recorded.
RESULTS
Among the 76 patients, the lung was the most common site of infection, and intensive care unit was the main hospital department. Extended spectrum beta-lactamase screening revealed expression by all 76 isolates of . Of the 76 isolates, 92.1% exhibited multiple drug resistance or extensive drug resistance. isolates were sensitive to cefepime and imipenem, but not to other beta-lactam antibiotics. Twenty isolates were resistant to all 21 types of antibiotics. Of the 20 patients infected with extensively drug-resistant isolates, nine (45%) died.
CONCLUSIONS
Drug resistance is increasing in . The antimicrobial agent imipenem may be effective for treatment of infections. Fluoroquinolones, aminoglycosides, and fourth-generation cephalosporins are suitable options for antibiotic therapy.
Topics: Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Enterobacteriaceae Infections; Humans; Microbial Sensitivity Tests; Providencia; Retrospective Studies
PubMed: 33081537
DOI: 10.1177/0300060520962296 -
Microorganisms Aug 2021In this paper, we describe the first complete genome sequence of species, a clinical multidrug-resistant strain harboring the New Delhi Metallo-β-lactamase-1 (NDM-1)...
In this paper, we describe the first complete genome sequence of species, a clinical multidrug-resistant strain harboring the New Delhi Metallo-β-lactamase-1 (NDM-1) gene, isolated at the Kinshasa University Teaching Hospital, in Democratic Republic of the Congo. Whole genome sequencing of an imipenem-resistant clinical Gram-negative P8538 isolate was performed using MiSeq and Gridion, and then complete genome analysis, plasmid search, resistome analysis, and comparative genomics were performed. Genome assembly resulted in a circular chromosome sequence of 4,280,811-bp and 40.80% GC and a circular plasmid (pPV8538_NDM-1) of 151,684-bp and 51.93%GC, which was identified in an P8540 strain isolated in the same hospital. Interestingly, comparative genomic analysis revealed multiple sequences acquisition within the P8538 chromosome, including three complete prophages, a siderophore biosynthesis NRPS cluster, a Type VI secretion system (T6SS), a urease gene cluster, and a complete Type-I-F CRISPR-Cas3 system. Β-lactamase genes, including and , were found on the recombinant plasmid pPV8538_NDM-1, in addition to other antibiotic resistance genes such as , -, , , , --, , and . Genome comparison with species revealed 82.95% of average nucleotide identity (ANI), with species exhibiting 90.79% of proteome similarity. We report the first complete genome of species and for the first time the presence of the gene in this species. This work highlights the need to improve surveillance and clinical practices in DR Congo in order to reduce or prevent the spread of such resistance.
PubMed: 34442831
DOI: 10.3390/microorganisms9081751 -
Genome Medicine 2015The human gut microbiome is associated with the development of colon cancer, and recent studies have found changes in the microbiome in cancer patients compared to...
BACKGROUND
The human gut microbiome is associated with the development of colon cancer, and recent studies have found changes in the microbiome in cancer patients compared to healthy controls. Studying the microbial communities in the tumor microenvironment may shed light on the role of host-bacteria interactions in colorectal cancer. Here, we highlight the major shifts in the colorectal tumor microbiome relative to that of matched normal colon tissue from the same individual, allowing us to survey the microbial communities in the tumor microenvironment and providing intrinsic control for environmental and host genetic effects on the microbiome.
METHODS
We sequenced the microbiome in 44 primary tumor and 44 patient-matched normal colon tissue samples to determine differentially abundant microbial taxa These data were also used to functionally characterize the microbiome of the cancer and normal sample pairs and identify functional pathways enriched in the tumor-associated microbiota.
RESULTS
We find that tumors harbor distinct microbial communities compared to nearby healthy tissue. Our results show increased microbial diversity in the tumor microenvironment, with changes in the abundances of commensal and pathogenic bacterial taxa, including Fusobacterium and Providencia. While Fusobacterium has previously been implicated in colorectal cancer, Providencia is a novel tumor-associated agent which has not been identified in previous studies. Additionally, we identified a clear, significant enrichment of predicted virulence-associated genes in the colorectal cancer microenvironment, likely dependent upon the genomes of Fusobacterium and Providencia.
CONCLUSIONS
This work identifies bacterial taxa significantly correlated with colorectal cancer, including a novel finding of an elevated abundance of Providencia in the tumor microenvironment. We also describe the predicted metabolic pathways and enzymes differentially present in the tumor-associated microbiome, and show an enrichment of virulence-associated bacterial genes in the tumor microenvironment. This predicted virulence enrichment supports the hypothesis that the microbiome plays an active role in colorectal cancer development and/or progression. Our results provide a starting point for future prognostic and therapeutic research with the potential to improve patient outcomes.
PubMed: 26170900
DOI: 10.1186/s13073-015-0177-8 -
BioRxiv : the Preprint Server For... Jun 2024is a Gram-negative bacterium found in a wide variety of water and land environments and organisms. It has been isolated as part of the gut microbiome of animals and...
is a Gram-negative bacterium found in a wide variety of water and land environments and organisms. It has been isolated as part of the gut microbiome of animals and insects, as well as from stool samples of patients with diarrhea. Specific strains encode gene homologs of virulence factors found in other pathogenic members of the same Enterobacterales order, such as serovar Typhimurium and Whether these genes are also pathogenic determinants in is not known. Here we have used 205/92, a clinical isolate, with and infection models to investigate -host interactions at the cellular level. Our particular focus was the role of two type III secretion systems (T3SS) belonging to the Inv-Mxi/Spa family. T3SS is widespread in spp. and encoded on the chromosome. T3SS is encoded on a large plasmid that is present in a subset of strains, which are primarily isolates from diarrheal patients. Using a combination of electron and fluorescence microscopy and gentamicin protection assays we show that 205/92 is internalized into eukaryotic cells, rapidly lyses its internalization vacuole and proliferates in the cytosol. This triggers caspase-4 dependent inflammasome responses in gut epithelial cells. The requirement for the T3SS in entry, vacuole lysis and cytosolic proliferation is host-cell type specific, playing a more prominent role in human intestinal epithelial cells as compared to macrophages. In a bovine ligated intestinal loop model, colonizes the intestinal mucosa, inducing mild epithelial damage with negligible fluid accumulation. No overt role for T3SS or T3SS was seen in the calf infection model. However, T3SS was required for the rapid killing of . We propose that the acquisition of two T3SS by horizontal gene transfer has allowed to diversify its host range, from a highly virulent pathogen of insects to an opportunistic gastrointestinal pathogen of animals.
PubMed: 38895369
DOI: 10.1101/2024.06.07.595826 -
Indian Journal of Critical Care... 2022The genus , earlier considered a rare pathogen, is now increasingly recognized as a notorious opportunistic pathogen capable of causing serious nosocomial infections,...
BACKGROUND
The genus , earlier considered a rare pathogen, is now increasingly recognized as a notorious opportunistic pathogen capable of causing serious nosocomial infections, mainly urinary tract infections (UTIs). Treating these infections is an onerous task given the resistance seen in clinical strains to many currently available antimicrobials. The objective of the present study is to provide an overall view into the prevalence of spp. causing UTIs, their antibiotic susceptibility pattern, and respective clinical outcomes.
MATERIALS AND METHODS
This is a retrospective observational study carried out in a tertiary care teaching referral hospital located in Jaipur, India from March 2021 to May 2021. All spp. strains isolated from urine samples were included in the study. Data were entered in Microsoft Office Excel worksheet. Results are presented in numbers and percentages.
RESULTS
Out of 1,261 urine samples processed in the laboratory during the study period, 426 were culture positive and the majority were gram-negative isolates and included (46.0%) and spp. (28.0%). spp. was the fourth most common gram-negative pathogen (6.0%). The median age of patients was 65 years. The male:female ratio was 3:2 and maximum patients belonged to the 30-60-year age-group. Diabetes was the commonest associated comorbidity. All patients had an indwelling urinary catheter. Three (20.0%) patients succumbed to infections.
CONCLUSION
is an opportunistic pathogen that cannot be neglected due to escalating antibiotic resistance. Effective infection control and antibiotic stewardship policies are required to prevent the development of further antibiotic resistance.
HOW TO CITE THIS ARTICLE
Rajni E, Jain A, Garg VK, Sharma R, Vohra R, Jain SS. Causing Urinary Tract Infections: Are We Reaching a Dead End? Indian J Crit Care Med 2022;26(4):446-451.
PubMed: 35656046
DOI: 10.5005/jp-journals-10071-24163 -
Anais Da Academia Brasileira de Ciencias 2022Providencia stuartii is one of the Enterobacteriaceae species of medical importance commonly associated with urinary infections, which can also cause other ones,...
Providencia stuartii is one of the Enterobacteriaceae species of medical importance commonly associated with urinary infections, which can also cause other ones, including uncommon ones, such as liver abscess and septic vasculitis. This bacterium stands out in the expression of intrinsic and acquired resistance to antimicrobials. Besides, it uses mechanisms such as biofilm for its persistence in biotic and abiotic environments. This study investigated the cellular hydrophobicity profile of clinical isolates of P. stuartii. It also analyzed genes related to the fimbrial adhesin in this species comparing with other reports described for other bacteria from Enterobacteriaceae family. The investigated isolates to form biofilm and had a practically hydrophilic cell surface profile. However, fimH and mrkD genes were not found in P. stuartii, unlike observed in other species of Enterobacteriaceae. These results show that P. stuartii has specificities regarding its potential for biofilm formation, which makes it difficult to destabilize the infectious process and increases the permanence of this pathogen in hospital units.
Topics: Biofilms; Drug Resistance, Multiple, Bacterial; Enterobacteriaceae Infections; Humans; Providencia
PubMed: 36074405
DOI: 10.1590/0001-3765202220210765 -
Antibiotics (Basel, Switzerland) May 2024Carbapenemase-producing spp. , , spp., and (CP-ESCPM) are increasingly identified as causative agents of nosocomial infections but are still not under systematic...
Carbapenemase-producing spp. , , spp., and (CP-ESCPM) are increasingly identified as causative agents of nosocomial infections but are still not under systematic genomic surveillance. In this study, using a combination of whole-genome sequencing and conjugation experiments, we sought to elucidate the genomic characteristics and transferability of resistance genes in clinical CP-ESCPM isolates from Bulgaria. Among the 36 sequenced isolates, NDM-1 (12/36), VIM-4 (11/36), VIM-86 (8/36), and OXA-48 (7/36) carbapenemases were identified; two isolates carried both NDM-1 and VIM-86. The majority of carbapenemase genes were found on self-conjugative plasmids. IncL plasmids were responsible for the spread of OXA-48 among , , and . IncM2 plasmids were generally associated with the spread of NDM-1 in and , and also of VIM-4 in . IncC plasmids were involved in the spread of the recently described VIM-86 in isolates. IncC plasmids carrying and were observed too. was also detected on IncX3 in and on IncT plasmid in . The significant resistance transfer rates we observed highlight the role of the ESCPM group as a reservoir of resistance determinants and stress the need for strengthening infection control measures.
PubMed: 38786183
DOI: 10.3390/antibiotics13050455 -
MSystems Apr 2021Phylosymbiosis is a cross-system trend whereby microbial community relationships recapitulate the host phylogeny. In parasitoid wasps, phylosymbiosis occurs throughout...
Phylosymbiosis is a cross-system trend whereby microbial community relationships recapitulate the host phylogeny. In parasitoid wasps, phylosymbiosis occurs throughout development, is distinguishable between sexes, and benefits host development and survival. Moreover, the microbiome shifts in hybrids as a rare bacterium in the microbiome becomes dominant. The larval hybrids then catastrophically succumb to bacterium-assisted lethality and reproductive isolation between the species. Two important questions for understanding phylosymbiosis and bacterium-assisted lethality in hybrids are (i) do the bacterial genomes differ from other animal isolates and (ii) are the hybrid bacterial genomes the same as those in the parental species? Here, we report the cultivation, whole-genome sequencing, and comparative analyses of the most abundant gut bacteria in larvae, and Characterization of new isolates shows forms a more robust biofilm than and that, when grown in coculture, significantly outcompetes genomes from are similar to each other and more divergent from pathogenic, human associates. from , , and their hybrid offspring are nearly identical and relatively distinct from human isolates. These results indicate that members of the larval gut microbiome within are most similar to each other, and the strain of the dominant in hybrids is resident in parental species. Holobiont interactions between shared, resident members of the wasp microbiome and the host underpin phylosymbiosis and hybrid breakdown. Animal and plant hosts often establish intimate relationships with their microbiomes. In varied environments, closely related host species share more similar microbiomes, a pattern termed phylosymbiosis. When phylosymbiosis is functionally significant and beneficial, microbial transplants between host species and host hybridization can have detrimental consequences on host biology. In the parasitoid wasp genus, which contains a phylosymbiotic gut community, both effects occur and provide evidence for selective pressures on the holobiont. Here, we show that bacterial genomes in differ from other environments and harbor genes with unique functions that may regulate phylosymbiotic relationships. Furthermore, the bacteria in hybrids are identical to those in parental species, thus supporting a hologenomic tenet that the same members of the microbiome and the host genome impact phylosymbiosis, hybrid breakdown, and speciation.
PubMed: 33824199
DOI: 10.1128/mSystems.01342-20