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Viruses Nov 2019The emergence of phage-resistant mutants is a key aspect of lytic phages-bacteria interaction and the main driver for the co-evolution between both organisms. Here, we...
The emergence of phage-resistant mutants is a key aspect of lytic phages-bacteria interaction and the main driver for the co-evolution between both organisms. Here, we analyze the impact of PA5oct jumbo phage treatment on planktonic/cell line associated and sessile population. Besides its broad-spectrum activity and efficient bacteria reduction in both airway surface liquid (ASL) model, and biofilm matrix degradation, PA5oct appears to persist in most of phage-resistant clones. Indeed, a high percentage of resistance (20/30 clones) to PA5oct is accompanied by the presence of phage DNA within bacterial culture. Moreover, the maintenance of this phage in the bacterial population correlates with reduced virulence, coupled with a sensitization to innate immune mechanisms, and a significantly reduced growth rate. We observed rather unusual consequences of PA5oct infection causing an increased inflammatory response of monocytes to . This phenomenon, combined with the loss or modification of the phage receptor, makes most of the phage-resistant clones significantly less pathogenic in in vivo model. These findings provide new insights into the general knowledge of giant phages biology and the impact of their application in phage therapy.
Topics: Biofilms; Mutation; Phage Therapy; Phenotype; Plankton; Pseudomonas Phages; Pseudomonas aeruginosa; Virulence
PubMed: 31771160
DOI: 10.3390/v11121089 -
Medical Science Monitor : International... Sep 2017BACKGROUND The antimicrobial mechanisms of ε-polylysine (EPL) against Pseudomonas aeruginosa and Aspergillus fumigatus biofilm were investigated. MATERIAL AND METHODS...
BACKGROUND The antimicrobial mechanisms of ε-polylysine (EPL) against Pseudomonas aeruginosa and Aspergillus fumigatus biofilm were investigated. MATERIAL AND METHODS We assessed the changes in electric conductivity of broth and total sugar concentration, as well as changes in phosphorous metabolism and protein expression, of the 2 organisms before and after treatment with EPL. RESULTS The experimental results showed that EPL has antimicrobial activity against Pseudomonas aeruginosa and Aspergillus fumigatus, but the activity was much stronger for the former. After treatment with EPL, the electric conductivity and total sugar concentration of microbial broth increased, suggesting that EPL damages the cell membrane structure, which increases permeability of the cell membrane and release of cell components. CONCLUSIONS The consumption of phosphorous decreased in the EPL-treated organisms, which seriously affected the synthesis of important cell components such as nucleic acid and phospholipid, as well as energy metabolism.
Topics: Anti-Bacterial Agents; Anti-Infective Agents; Aspergillus fumigatus; Biofilms; Microbial Sensitivity Tests; Polylysine; Pseudomonas aeruginosa
PubMed: 28863128
DOI: 10.12659/msm.903145 -
Frontiers in Cellular and Infection... 2021is a common opportunistic pathogen that causes acute nosocomial necrotizing pneumonia and is the predominant source of chronic lung infections in patients with the...
is a common opportunistic pathogen that causes acute nosocomial necrotizing pneumonia and is the predominant source of chronic lung infections in patients with the genetic disorder cystic fibrosis. Early diagnosis in infected patients and monitoring contamination is therefore of great importance in controlling disease spread and development with timely drugs intervention treatment and cut off infection source. Traditional culture-biochemical methods are time consuming and highly dependent on technicians and expensive instruments. To address these challenges, the present study aimed to develop a rapid, sensitive, and specific, on-site detection method for based on recombinase polymerase amplification (RPA) combined with lateral flow strip (LFS) technology. The experimental process included screening and modification of primer and probe sets targeting the unique virulence gene (); specificity detection in 29 strains of and 23 closely-related pathogenic bacteria; sensitivity measurements with gradient-diluted genomic DNA and probit regression analysis; and clinical application evaluation using 574 patients samples and calculating coincidence rate and kappa index value in comparison with the culture-biochemical method. The RPA-LFS assay could complete the amplification process at 37°C constant temperature within 30 min and results could be visualized by the naked eye within 10 min on LFS. The assay displayed high sensitivity with a limit of detection of 3.05 CFU/reaction. It also demonstrated high specificity by showing no cross reaction with other pathogenic bacteria, and rapidness by being completed in less than an hour. Furthermore, when used with clinical samples, the assay had a coincidence rate of 98.26% with the culture-biochemical method and a kappa index value of 0.9433. These data indicate that the RPA-LFS assay represents a major improvement for detection, especially in resource-limited areas.
Topics: Humans; Nucleic Acid Amplification Techniques; Pseudomonas aeruginosa; Recombinases; Sensitivity and Specificity; Technology
PubMed: 34595129
DOI: 10.3389/fcimb.2021.698929 -
Biomolecules Dec 2020is an important multidrug-resistant human pathogen by dint of its high intrinsic, acquired, and adaptive resistance mechanisms, causing great concern for...
is an important multidrug-resistant human pathogen by dint of its high intrinsic, acquired, and adaptive resistance mechanisms, causing great concern for immune-compromised individuals and public health. Additionally, resilience lies in the production of a myriad of virulence factors, which are known to be tightly regulated by the quorum sensing (QS) system. Anti-virulence therapy has been adopted as an innovative alternative approach to circumvent bacterial antibiotic resistance. Since plants are known repositories of natural phytochemicals, herein, we explored the anti-virulence potential of , a medicinal plant from the Taira Atacama community (Calama, Chile), against . Interestingly, extract (E) conferred a significant protection for human lung cells and nematodes towards pathogenicity. The production of key virulence factors was decreased upon E exposure without affecting growth. In addition, E was able to decrease QS-molecules production. Furthermore, metabolite profiling of E and its derived fractions achieved by combination of a molecular network and in silico annotation allowed the putative identification of fourteen diterpenoids bearing a mulinane-like skeleton. Remarkably, this unique interesting group of diterpenoids seems to be responsible for the interference with virulence factors as well as on the perturbation of membrane homeostasis of . Hence, there was a significant increase in membrane stiffness, which appears to be modulated by the cell wall stress response ECFσ SigX, an extracytoplasmic function sigma factor involved in membrane homeostasis as well as virulence.
Topics: Animals; Anti-Bacterial Agents; Apiaceae; Biofilms; Diterpenes; Drug Resistance, Bacterial; Humans; Pseudomonas aeruginosa; Quorum Sensing; Virulence
PubMed: 33276611
DOI: 10.3390/biom10121626 -
Journal of Infection in Developing... Oct 2019Pseudomonas aeruginosa is an ubiquitous bacterium causes various community-acquired and nosocomial infections. In this investigation, we aimed to screen the antibiotic...
INTRODUCTION
Pseudomonas aeruginosa is an ubiquitous bacterium causes various community-acquired and nosocomial infections. In this investigation, we aimed to screen the antibiotic susceptibility patterns and the prevalence of virulence factor genes in a set of Pseudomonas aeruginosa isolated from nosocomial and community-acquired infections in the Northwestern of Morocco.
METHODOLOGY
A total of 155 of Pseudomonas aeruginosa strains were collected (January 2015 - December 2016) from nosocomial and community-acquired infections at hospital centers and clinical laboratories in the Northwestern of Morocco. Antimicrobial susceptibility test was performed by the standard disk diffusion method. In addition, PCR assays were used for screening five virulence encoding genes (lasB, algD, plcH, exoA, and exoS).
RESULTS
Our results revealed that high level of antimicrobial resistance was detected towards aztreonam (27.1%) followed by meropenem (14.2%). The resistance to imipenem was significantly higher in strains isolated from nosocomial infections (12.7%) than strains isolated from community-acquired infections (1.5%). The results highlighted that lasB (98.7%) and exoS (98.7%) were the most frequent virulence genes.
CONCLUSIONS
This survey provides data about phenotypic and genotypic properties of Pseudomonas aeruginosa emerged in the Northwestern of Morocco. It could be helpful for the health workers to improve infection control measures and to establish a surveillance system.
Topics: Anti-Bacterial Agents; Genes, Bacterial; Humans; Microbial Sensitivity Tests; Morocco; Pseudomonas Infections; Pseudomonas aeruginosa; Virulence; Virulence Factors
PubMed: 32084019
DOI: 10.3855/jidc.10675 -
PloS One 2015Following the identification of a case of severe clinical mastitis in a Saanen dairy goat (goat A), an average of 26 lactating goats in the herd was monitored over a...
Following the identification of a case of severe clinical mastitis in a Saanen dairy goat (goat A), an average of 26 lactating goats in the herd was monitored over a period of 11 months. Milk microbiological analysis revealed the presence of Pseudomonas aeruginosa in 7 of the goats. Among these 7 does, only goat A showed clinical signs of mastitis. The 7 P. aeruginosa isolates from the goat milk and 26 P. aeruginosa isolates from environmental samples were clustered by RAPD-PCR and PFGE analyses in 3 genotypes (G1, G2, G3) and 4 clusters (A, B, C, D), respectively. PFGE clusters A and B correlated with the G1 genotype and included the 7 milk isolates. Although it was not possible to identify the infection source, these results strongly suggest a spreading of the infection from goat A. Clusters C and D overlapped with genotypes G2 and G3, respectively, and included only environmental isolates. The outcome of the antimicrobial susceptibility test performed on the isolates revealed 2 main patterns of multiple resistance to beta-lactam antibiotics and macrolides. Virulence related phenotypes were analyzed, such as swarming and swimming motility, production of biofilm and production of secreted virulence factors. The isolates had distinct phenotypic profiles, corresponding to genotypes G1, G2 and G3. Overall, correlation analysis showed a strong correlation between sampling source, RAPD genotype, PFGE clusters, and phenotypic clusters. The comparison of the levels of virulence related phenotypes did not indicate a higher pathogenic potential in the milk isolates as compared to the environmental isolates.
Topics: Animal Diseases; Animals; Anti-Bacterial Agents; Cluster Analysis; Environmental Microbiology; Female; Genotype; Goats; Mastitis; Microbial Sensitivity Tests; Molecular Typing; Phenotype; Phylogeny; Pseudomonas aeruginosa; Virulence Factors
PubMed: 26606430
DOI: 10.1371/journal.pone.0142973 -
Archives of Razi Institute Oct 2022() is a ubiquitous opportunistic organism that is hard to treat. This study aimed to investigate the association of , , and prevalence with Cyclic di-GMP (c-di-GMP)...
() is a ubiquitous opportunistic organism that is hard to treat. This study aimed to investigate the association of , , and prevalence with Cyclic di-GMP (c-di-GMP) in . To this end, 27 clinical isolates of were obtained from different hospitals in Baghdad, Iraq. The phenotypic detection of carbapenem and biofilm assays was performed by the M63 minimal medium, supplemented with glucose, magnesium sulfate. The polymerase chain reaction was utilized to detect carbapenem genes. The results showed that the isolates were highly resistant to Imipenem (37%) and Meropenem (63%). Imipenem (37%) and Meropenem (63%) demonstrated a moderate sensitivity against . The No.5 showed high resistance to carbapenem by , , and , followed by a robust biofilm confirmed with c-di-GMP levels and the twitching motility ability. Upon these findings, the use of antibiotics should be restricted to severe bacterial infections to avoid the rapid emergence of new resistant isolates, which leads to the hard treatment of infection with . It is highly recommended that these findings be notified for infectious control. Future studies can investigate the link between transferable resistant genes and c-di-GMP values.
Topics: Bacterial Proteins; beta-Lactamases; Carbapenems; Imipenem; Meropenem; Pseudomonas aeruginosa; Biofilms
PubMed: 37123152
DOI: 10.22092/ARI.2022.358104.2153 -
MBio Dec 2021Pyocins are phage tail-like protein complexes that can be used by Pseudomonas aeruginosa to enact intraspecies competition by killing competing strains. The pyocin gene...
Pyocins are phage tail-like protein complexes that can be used by Pseudomonas aeruginosa to enact intraspecies competition by killing competing strains. The pyocin gene cluster also encodes holin and lysin enzymes that lyse producer cells to release the pyocins. The best-known inducers of pyocin production under laboratory conditions are DNA-damaging agents, including fluoroquinolone antibiotics, that activate the SOS response. Here, we report the discovery of an alternate, RecA-independent pathway of strong pyocin induction that is active in cells deficient for the tyrosine recombinase XerC. When Δ cells were examined at the single-cell level, only a fraction of the cell population strongly expressed pyocins before explosively lysing, suggesting a that a built-in heterogenous response system protects the cell population from widespread lysis. Disabling the holin and lysin enzymes or deleting the entire pyocin gene cluster blocked explosive lysis and delayed but did not prevent the death of pyocin-producing cells, suggesting that Δ cells activate other lysis pathways. Mutating XerC to abolish its recombinase activity induced pyocin expression to a lesser extent than the full deletion, suggesting that XerC has multiple functions with respect to pyocin activation. Our studies uncover a new pathway for pyocin production and highlight its response across a genetically identical population. Moreover, our finding that Δ populations are hypersensitive to fluoroquinolones raises the intriguing possibility that XerC inhibition may potentiate the activity of these antibiotics against P. aeruginosa infections. Pseudomonas aeruginosa is a versatile and ubiquitous bacterium that frequently infects humans as an opportunistic pathogen. P. aeruginosa competes with other strains within the species by producing killing complexes termed pyocins, which are only known to be induced by cells experiencing DNA damage and the subsequent SOS response. Here, we discovered that strains lacking a recombinase enzyme called XerC strongly produce pyocins independently of the SOS response. We also show that these strains are hypersensitive to commonly used fluoroquinolone antibiotic treatment and that fluoroquinolones further stimulate pyocin production. Thus, XerC is an attractive target for future therapies that simultaneously sensitize P. aeruginosa to antibiotics and stimulate the production of bactericidal pyocins.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Fluoroquinolones; Pseudomonas aeruginosa; Pyocins; Recombinases; SOS Response, Genetics
PubMed: 34809462
DOI: 10.1128/mBio.02893-21 -
Applied and Environmental Microbiology Nov 2014In microaerophilic or anaerobic environments, Pseudomonas aeruginosa utilizes nitrate reduction for energy production, a process dependent on the availability of the...
In microaerophilic or anaerobic environments, Pseudomonas aeruginosa utilizes nitrate reduction for energy production, a process dependent on the availability of the oxyanionic form of molybdenum, molybdate (MoO4 (2-)). Here, we show that molybdate acquisition in P. aeruginosa occurs via a high-affinity ATP-binding cassette permease (ModABC). ModA is a cluster D-III solute binding protein capable of interacting with molybdate or tungstate oxyanions. Deletion of the modA gene reduces cellular molybdate concentrations and results in inhibition of anaerobic growth and nitrate reduction. Further, we show that conditions that permit nitrate reduction also cause inhibition of biofilm formation and an alteration in fatty acid composition of P. aeruginosa. Collectively, these data highlight the importance of molybdate for anaerobic growth of P. aeruginosa and reveal novel consequences of nitrate reduction on biofilm formation and cell membrane composition.
Topics: ATP-Binding Cassette Transporters; Anaerobiosis; Fatty Acids; Gene Deletion; Molybdenum; Nitrates; Oxidation-Reduction; Pseudomonas aeruginosa
PubMed: 25172858
DOI: 10.1128/AEM.02465-14 -
BMC Genomics Jul 2021Pseudomonas aeruginosa is a ubiquitous environmental microorganism and also a common cause of infection. Its ability to survive in many different environments and...
BACKGROUND
Pseudomonas aeruginosa is a ubiquitous environmental microorganism and also a common cause of infection. Its ability to survive in many different environments and persistently colonize humans is linked to its presence in biofilms formed on indwelling device surfaces. Biofilm promotes adhesion to, and survival on surfaces, protects from desiccation and the actions of antibiotics and disinfectants.
RESULTS
We examined the genetic basis for biofilm production on polystyrene at room (22 °C) and body temperature (37 °C) within 280 P. aeruginosa. 193 isolates (69 %) produced more biofilm at 22 °C than at 37 °C. Using GWAS and pan-GWAS, we found a number of accessory genes significantly associated with greater biofilm production at 22 °C. Many of these are present on a 165 kb region containing genes for heavy metal resistance (arsenic, copper, mercury and cadmium), transcriptional regulators and methytransferases. We also discovered multiple core genome SNPs in the A-type flagellin gene and Type II secretion system gene xpsD. Analysis of biofilm production of isolates of the MDR ST111 and ST235 lineages on stainless-steel revealed several accessory genes associated with enhanced biofilm production. These include a putative translocase with homology to a Helicobacter pylori type IV secretion system protein, a TA system II toxin gene and the alginate biosynthesis gene algA, several transcriptional regulators and methytransferases as well as core SNPs in genes involved in quorum sensing and protein translocation.
CONCLUSIONS
Using genetic association approaches we discovered a number of accessory genes and core-genome SNPs that were associated with enhanced early biofilm formation at 22 °C compared to 37 °C. These included a 165 kb genomic island containing multiple heavy metal resistance genes, transcriptional regulators and methyltransferases. We hypothesize that this genomic island may be associated with overall genotypes that are environmentally adapted to survive at lower temperatures. Further work to examine their importance in, for example gene-knockout studies, are required to confirm their relevance. GWAS and pan-GWAS approaches have great potential as a first step in examining the genetic basis of novel bacterial phenotypes.
Topics: Anti-Bacterial Agents; Biofilms; Drug Resistance, Multiple, Bacterial; Genotype; Humans; Pseudomonas Infections; Pseudomonas aeruginosa; Quorum Sensing
PubMed: 34311706
DOI: 10.1186/s12864-021-07818-5