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Current Biology : CB Jun 2024Strain-specific pili enable Vibrio cholerae bacteria to adhere to each other and form aggregates in liquid culture. A new study focuses on strains with less specific,...
Strain-specific pili enable Vibrio cholerae bacteria to adhere to each other and form aggregates in liquid culture. A new study focuses on strains with less specific, promiscuous pili and suggests a role for contact-dependent bacterial killing in shaping the composition of these aggregates.
Topics: Vibrio cholerae; Fimbriae, Bacterial; Bacterial Adhesion
PubMed: 38834027
DOI: 10.1016/j.cub.2024.04.042 -
Nanoscale Jun 2024Type IV pili (TFP) contribute to the ability of microbes such as to engage with and move across surfaces. We reported previously that TFP generate retractive forces of...
Type IV pili (TFP) contribute to the ability of microbes such as to engage with and move across surfaces. We reported previously that TFP generate retractive forces of ∼30 pN and provided indirect evidence that TFP-mediated surface attachment was enhanced in the presence of the Pel polysaccharide. Here, we use different mutants defective in flagellar, Pel production or TFP production - alone or in combination - to decipher the relative contribution of these biofilm-promoting factors for adhesion. By means of atomic force microscopy (AFM), we show that mutating the flagellum (Δ mutant) results in an increase in Pel polysaccharide production, but this increase in Pel does not result in an increase in surface adhesive properties compared to those previously described for the WT strain. By blocking Pel production in the Δ mutant (ΔΔ), we directly show that TFP play a major role in the adhesion of the bacteria to hydrophobic AFM tips, but that the adhesion force is only slightly impaired by the absence of Pel. Inversely, performing single-cell force spectroscopy measurements with the mutant lacking TFP (ΔΔ) reveals that the Pel can modulate the attachment of the bacteria to a hydrophobic substrate in a time-dependent manner. Finally, little adhesion was detected for the ΔΔΔ triple mutant, suggesting that both TFP and Pel polysaccharide make a substantial contribution to bacteria-substratum interaction events. Altogether, our data allow us to decipher the relative contribution of Pel and TFP in the early attachment by .
Topics: Pseudomonas aeruginosa; Microscopy, Atomic Force; Fimbriae, Bacterial; Bacterial Adhesion; Polysaccharides, Bacterial; Biofilms; Flagella; Bacterial Proteins; Mutation
PubMed: 38832761
DOI: 10.1039/d4nr01415d -
Preventive Veterinary Medicine Jul 2024Despite the prevalence of co-infections and the association of over 50 viral and 46 bacterial pathogens with pig diseases, little is known about their simultaneous...
Despite the prevalence of co-infections and the association of over 50 viral and 46 bacterial pathogens with pig diseases, little is known about their simultaneous occurrence, particularly in commercial pig farming environments where health programs are in place. To address this knowledge gap, this study aimed to evaluate the pathogen threshold of respiratory and enteric pathogens in pig herds using the Pork MultiPath™ (PMP1 and PMP2, respiratory and enteric respectively) technology, which detects multiple pathogens simultaneously in a single reaction with high sensitivity and specificity. In this study the most prevalent respiratory pathogens, Mycoplasma hyrohinis, Pasteurella multocida, and Haemophilus parasuis detected by PMP1 were effectively controlled during the nursery stage through strategic treatment with tiamulin. Even though the major respiratory incidences were reduced, the recorded coughing and sneezing rates were associated with the levels of H. parasuis and M. hyrohinis, which were set at 1356 and 1275 copies/reaction, respectively. In addition, one of the identified co-infection patterns indicated a strong relationship between the occurrence of H. parasuis and M. hyorhinis at the sample and pen levels, highlighting the high likelihood of detecting these two pathogens together. Testing with enteric panel PMP2 revealed that the most frequently detected virulence factors during the early nursery stage were Escherichia coli genes for toxins - ST1, ST2, and fimbriae - F4 and F18. Moreover, a co-infection with Rotavirus B and C was often observed during the nursery stage, and a strong positive correlation between these two markers has been identified. Additionally, the levels of several markers, namely E. coli F4, F5, F18, LT, ST1, and ST2, have been associated with a higher likelihood of sickness in pig populations. In addition, the onset of Brachyspira pilosicoli during the nursery and grower stages was found to be associated with an increased risk of diarrhoea, with a set threshold at around 500 copies/reaction. Although simultaneous detection of multiple pathogens is not yet widely used in the pig industry, it offers a significant advantage in capturing the diversity and interactions of co-infections. Testing pooled samples with Pork MultiPath™ is cost-effective and practical to regularly monitor the health status of pig populations.
Topics: Animals; Swine Diseases; Swine; Coinfection; Epidemiological Monitoring
PubMed: 38820832
DOI: 10.1016/j.prevetmed.2024.106237 -
Journal of Bacteriology Jun 2024Many prokaryotes use swimming motility to move toward favorable conditions and escape adverse surroundings. Regulatory mechanisms governing bacterial flagella-driven...
Many prokaryotes use swimming motility to move toward favorable conditions and escape adverse surroundings. Regulatory mechanisms governing bacterial flagella-driven motility are well-established; however, little is yet known about the regulation underlying swimming motility propelled by the archaeal cell surface structure, the archaella. Previous research showed that the deletion of the adhesion pilins (PilA1-6), subunits of the type IV pili cell surface structure, renders the model archaeon non-motile. In this study, we used ethyl methanesulfonate mutagenesis and a motility assay to identify motile suppressors of the ∆[] strain. Of the eight suppressors identified, six contain missense mutations in archaella biosynthesis genes, and expression of and mutant constructs in the respective multi-deletion strains ∆[]∆ and ∆[]∆ confirmed their role in suppressing the ∆[] motility defect. Additionally, three suppressors harbor co-occurring disruptive missense and nonsense mutations in , a gene encoding a proposed regulatory protein. A deletion of resulted in hypermotility, while expression in wild-type cells led to decreased motility. Moreover, quantitative real-time PCR analysis revealed that in wild-type cells, higher expression levels of , , and the archaellin gene were observed in motile early-log phase rod-shaped cells compared to non-motile mid-log phase disk-shaped cells. Conversely, ∆ cells, which form rods during both early- and mid-log phases, exhibited similar expression levels of genes in both growth phases. Our findings contribute to a deeper understanding of the mechanisms governing archaeal motility, highlighting the involvement of ArlI, ArlJ, and CirA in pilin-mediated motility regulation.IMPORTANCEArchaea are close relatives of eukaryotes and play crucial ecological roles. Certain behaviors, such as swimming motility, are thought to be important for archaeal environmental adaptation. Archaella, the archaeal motility appendages, are evolutionarily distinct from bacterial flagella, and the regulatory mechanisms driving archaeal motility are largely unknown. Previous research has linked the loss of type IV pili subunits to archaeal motility suppression. This study reveals three proteins involved in pilin-mediated motility regulation, offering a deeper understanding of motility regulation in this understudied domain while also paving the way for uncovering novel mechanisms that govern archaeal motility. Understanding archaeal cellular processes will help elucidate the ecological roles of archaea as well as the evolution of these processes across domains.
Topics: Haloferax volcanii; Fimbriae Proteins; Archaeal Proteins; Gene Expression Regulation, Archaeal
PubMed: 38819156
DOI: 10.1128/jb.00089-24 -
Antonie Van Leeuwenhoek May 2024Pseudoalteromonas piscicida 2515, isolated from Litopenaeus vannamei culture water, is a potential marine probiotic with broad anti-Vibrio properties. However, genomic...
Pseudoalteromonas piscicida 2515, isolated from Litopenaeus vannamei culture water, is a potential marine probiotic with broad anti-Vibrio properties. However, genomic information on P. piscicida 2515 is scarce. In this study, the general genomic characteristics and probiotic properties of the P. piscicida 2515 strain were analysed. In addition, we determined the antibacterial mechanism of this bacterial strain by scanning electron microscopy (SEM). The results indicated that the whole-genome sequence of P. piscicida 2515 contained one chromosome and one plasmid, including a total length of 5,541,406 bp with a G + C content of 43.24%, and 4679 protein-coding genes were predicted. Various adhesion-related genes, amino acid and vitamin metabolism and biosynthesis genes, and stress-responsive genes were found with genome mining tools. The presence of genes encoding chitin, bromocyclic peptides, lantibiotics, and sactipeptides showed the strong antibacterial activity of the P. piscicida 2515 strain. Moreover, in coculture with Vibrio anguillarum, P. piscicida 2515 displayed vesicle/pilus-like structures located on its surface that possibly participated in its bactericidal activity, representing an antibacterial mechanism. Additionally, 16 haemolytic genes and 3 antibiotic resistance genes, including tetracycline, fluoroquinolone, and carbapenem were annotated, but virulence genes encoding enterotoxin FM (entFM), cereulide (ces), and cytotoxin K were not detected. Further tests should be conducted to confirm the safety characteristics of P. piscicida 2515, including long-term toxicology tests, ecotoxicological assessment, and antibiotic resistance transfer risk assessment. Our results here revealed a new understanding of the probiotic properties and antibacterial mechanism of P. piscicida 2515, in addition to theoretical information for its application in aquaculture.
Topics: Pseudoalteromonas; Vibrio; Whole Genome Sequencing; Genome, Bacterial; Animals; Probiotics; Anti-Bacterial Agents; Penaeidae; Phylogeny; Base Composition
PubMed: 38809302
DOI: 10.1007/s10482-024-01974-w -
European Journal of Clinical... May 2024Corynebacterium striatum is an emerging nosocomial pathogen. This is the first report showing the presence of three distinct multidrug resistant lineages of C. striatum...
Corynebacterium striatum is an emerging nosocomial pathogen. This is the first report showing the presence of three distinct multidrug resistant lineages of C. striatum among patients in a UK hospital. The presence of ErmX, Tet(W), Bla and AmpC proteins, and mutations in gyrA gene are associated with the resistance to clindamycin, doxycycline, penicillin and moxifloxacin, respectively. These strains are equipped with several corynebacterial virulence genes including two SpaDEF-type and a novel pilus gene cluster, which needs further molecular characterisation. This study highlights a need of developing an active surveillance strategy for routine monitoring and preventing potential cross-transmission among susceptible patients.
PubMed: 38801486
DOI: 10.1007/s10096-024-04857-0 -
Emerging Microbes & Infections Dec 2024Ceftazidime-avibactam resistance attributable to the gene mutation is increasingly documented in clinical settings. In this study, we characterized the mechanisms...
Ceftazidime-avibactam resistance attributable to the gene mutation is increasingly documented in clinical settings. In this study, we characterized the mechanisms leading to the development of ceftazidime-avibactam resistance in ST11-K47 hypervirulent that harboured the gene. This strain possessed fimbriae and biofilm, demonstrating pathogenicity. Compared with the wild-type KPC-2 carbapenemase, the novel KPC-135 enzyme exhibited a deletion of Glu168 and Leu169 and a 15-amino acid tandem repeat between Val262 and Ala276. The gene was located within the Tn transposon truncated by IS and carried on an IncFII/IncR-type plasmid. Compared to the -positive cloned strain, only the MIC of ceftazidime increased against -positive and wasn't inhibited by avibactam (MIC 32 μg/mL), while clavulanic acid and vaborbactam demonstrated some inhibition. Kinetic parameters revealed that KPC-135 exhibited a lower and cat/ with ceftazidime and carbapenems, and a higher (∼26-fold) 50% inhibitory concentration with avibactam compared to KPC-2. The KPC-135 enzyme exerted a detrimental effect on fitness relative to the wild-type strain. Furthermore, this strain possessed hypervirulent determinants, which included the IncHI1B/FIB plasmid with and expression of type 1 and 3 fimbriae. In conclusion, we reported a novel KPC variant, KPC-135, in a clinical ST11-K47 hypervirulent strain, which conferred ceftazidime-avibactam resistance, possibly through increased ceftazidime affinity and decreased avibactam susceptibility. This strain simultaneously harboured resistance and virulence genes, posing an elevated challenge in clinical treatment.
Topics: Ceftazidime; Klebsiella pneumoniae; Azabicyclo Compounds; Drug Combinations; Anti-Bacterial Agents; Klebsiella Infections; Microbial Sensitivity Tests; beta-Lactamases; Bacterial Proteins; Humans; Virulence; Biofilms; Drug Resistance, Multiple, Bacterial; Plasmids; Animals
PubMed: 38801099
DOI: 10.1080/22221751.2024.2361007 -
Microorganisms May 2024Conjugation of carbohydrates to nanomaterials has been extensively studied and recognized as an alternative in the biomedical field. Dendrimers synthesized with mannose...
Conjugation of carbohydrates to nanomaterials has been extensively studied and recognized as an alternative in the biomedical field. Dendrimers synthesized with mannose at the end group and with entrapped zero-valent copper/silver could be a potential candidate against bacterial proliferation. This study is aimed at investigating the bactericidal activity of metal-glycodendrimers. The Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction was used to synthesize a new mannosylated dendrimer containing 12 mannopyranoside residues in the periphery. The enterotoxigenic fimbriae 4 (ETEC:F4) viability, measured at 600 nm, showed the half-inhibitory concentration (IC) of metal-free glycodendrimers (D), copper-loaded glycodendrimers (D:Cu) and silver-loaded glycodendrimers (D:Ag) closed to 4.5 × 10, 3.5 × 10 and to 1.0 × 10 µg/mL, respectively, and minimum inhibitory concentration (MIC) of D, D:Cu and D:Ag of 2.0, 1.5 and 1.0 × 10 µg/mL, respectively. The release of bacteria contents onto broth and the inhibition of ETEC:F4 biofilm formation increased with the number of metallo-glycodendrimer materials, with a special interest in silver-containing nanomaterial, which had the highest activity, suggesting that glycodendrimer-based materials interfered with bacteria-bacteria or bacteria-polystyrene interactions, with bacteria metabolism and can disrupt bacteria cell walls. Our findings identify metal-mannose-dendrimers as potent bactericidal agents and emphasize the effect of entrapped zero-valent metal against ETEC:F4.
PubMed: 38792795
DOI: 10.3390/microorganisms12050966 -
International Journal of Molecular... May 2024The gene cluster for Type IV pilus (Tfp) biosynthesis is commonly present and highly conserved in . Nevertheless, Tfp-mediated twitching motility is less common among...
The gene cluster for Type IV pilus (Tfp) biosynthesis is commonly present and highly conserved in . Nevertheless, Tfp-mediated twitching motility is less common among strains, and the factors determining twitching activity are not fully understood. Here, we analyzed the functions of three major pilin proteins (PilA1, PilA2, and PilA3) in the assembly and activity of Tfp in motile CGMH010. Using various recombinant deletion strains, we found that Tfp composed of different PilA proteins varied morphologically and functionally. Among the three PilA proteins, PilA1 was most critical in the assembly of twitching-active Tfp, and recombinant strains expressing motility generated more structured biofilms under constant shearing forces compared to the non-motile recombinant strains. Although PilA1 and PilA3 shared 94% identity, PilA3 could not compensate for the loss of PilA1, suggesting that the nature of PilA proteins plays an essential role in twitching activity. The single deletion of individual genes had little effect on the invasion of host endothelia by CGMH010. In contrast, the deletion of all three genes or , encoding the retraction ATPase, abolished Tfp-mediated invasion. Tfp- and PilT-dependent invasion were also detected in the non-motile SK36, and thus, the retraction of Tfp, but not active twitching, was found to be essential for invasion.
Topics: Fimbriae Proteins; Streptococcus sanguis; Fimbriae, Bacterial; Biofilms; Bacterial Proteins
PubMed: 38791440
DOI: 10.3390/ijms25105402 -
Veterinary Sciences May 2024Diarrhea is the most common issue in sheep farms, typically due to pathogenic () infections, such as F17. microRNA, a primary type of non-coding RNA, has been shown to...
Diarrhea is the most common issue in sheep farms, typically due to pathogenic () infections, such as F17. microRNA, a primary type of non-coding RNA, has been shown to be involved in diarrhea caused by pathogenic . To elucidate the profound mechanisms of miRNA in F17 infections, methods such as F17 adhesion assay, colony counting assay, relative quantification of bacterial fimbriae gene expression, indirect immune fluorescence (IF), Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), Western blotting (WB), and scratch assay were conducted to investigate the effect of miR-329b-5p overexpression/knock-down on F17 susceptibility of sheep intestinal epithelial cells (IECs). The findings indicated that miR-329b-5p enhances the F17 resistance of sheep IECs to F17 by promoting adhesion between F17 and IEC, as well as IEC proliferation and migration. In summary, miR-329b-5p plays a crucial role in the defense of sheep IECs against F17 infection, providing valuable insights into its mechanism of action.
PubMed: 38787178
DOI: 10.3390/vetsci11050206