Chlorhexidine Promotes Psl Expression in Pseudomonas aeruginosa That Enhances Cell Aggregation with Preserved Pathogenicity Demonstrates an Adaptation against Antiseptic

Abstract

Because Pseudomonas aeruginosa is frequently in contact with Chlorhexidine (a regular antiseptic), bacterial adaptations are possible. In comparison with the parent strain, the Chlorhexidine-adapted strain formed smaller colonies with metabolic downregulation (proteomic analysis) with the cross-resistance against colistin (an antibiotic for several antibiotic-resistant bacteria), partly through the modification of L-Ara4N in the lipopolysaccharide at the outer membrane. Chlorhexidine-adapted strain formed dense liquid–solid interface biofilms with enhanced cell aggregation partly due to the Chlorhexidine-induced overexpression of psl (exopolysaccharide-encoded gene) through the LadS/GacSA pathway (c-di-GMP-independence) in 12 h biofilms and maintained the aggregation with SiaD-mediated c-di-GMP dependence in 24 h biofilms as evaluated by polymerase chain reaction (PCR). The addition of Ca2+ in the Chlorhexidine-adapted strain facilitated several Psl-associated genes, indicating an impact of Ca2+ in Psl production. The activation by Chlorhexidine-treated sessile bacteria demonstrated a lower expression of IL-6 and IL-8 on fibroblasts and macrophages than the activation by the parent strain, indicating the less inflammatory reactions from Chlorhexidine-exposed bacteria. However, the 14-day severity of the wounds in mouse caused by Chlorhexidine-treated bacteria versus the parent strain was similar, as indicated by wound diameters and bacterial burdens. In conclusion, Chlorhexidine induced psl over-expression and colistin cross-resistance that might be clinically important.

The Regulatory Roles of Ezh2 in Response to Lipopolysaccharide (LPS) in Macrophages and Mice with Conditional Ezh2 Deletion with LysM-Cre System

“…Notably, the supernatant of the stimulated cells in all groups was gently removed, and washed with DMEM, before the re-administration of LPS or DMEM as mentioned in previous publications [ 24 , 102 , 103 ]. Supernatant cytokines (TNF-α, IL-6, and IL-10) were evaluated by ELISA (Invitrogen, Carlsbad, CA, USA) and the gene expression was evaluated by quantitative real-time polymerase chain reaction (PCR) as previously described [ 104 , 105 , 106 , 107 ]. Briefly, the RNA was extracted from the cells with TRIzol Reagent (Invitrogen, Carlsbad, CA, USA) together with RNeasy Mini Kit (Qiagen, Hilden, Germany) as 1 mg of total RNA was used for cDNA synthesis with iScript reverse transcription supermix (Bio-Rad, Hercules, CA, USA).…”

“…The RNA sequencing analysis was performed to determine the influence of epigenetic alteration in LPS-activated macrophages. As such, bone-marrow-derived macrophages were prepared from the femurs of wild-type (WT) mice using supplemented Dulbecco’s Modified Eagle’s Medium (DMEM) with a 20% conditioned medium of the L929 cells (ATCC CCL-1), which are fibroblasts used as a source of macrophage colony-stimulating factor as previously published [ 51 , 52 , 54 , 107 ]. Then, the macrophages at 5 × 10 4 cells/well in supplemented DMEM (Thermo Fisher Scientific) were incubated in 5% carbon dioxide (CO 2 ) at 37 °C for 24 h before being treated by LPS stimulation (100 mg/mL), and control DMEM for 24 h. For transcriptome analysis, the RNA from macrophages was extracted by RNeasy mini kit (Qiagen) and processing with the RNA sequencing of BGISEQ-50 platform based on triplicate macrophage samples as previously published [ 108 ].…”

Lacticaseibacillus rhamnosus dfa1 Attenuate Cecal Ligation-Induced Systemic Inflammation through the Interference in Gut Dysbiosis, Leaky Gut, and Enterocytic Cell Energy

“…After that, this cell-free supernatant (0.5 mL) was concentrated by speed vacuum drying at 40 °C for 3 h (Savant Instruments, Farmingdale, NY, USA) and stored at −20 °C until use [ 101 ]. Then, the LCM pellets, resuspended in DMEM (5% LCM) or DMEM alone (Media), in an equal volume were incubated in the Caco-2 cells with starvation before the sample collection for supernatant cytokines by ELISA (Invitrogen) or gene expression with quantitative real-time polymerase chain reaction (PCR) following previous publications [ 102 , 103 , 104 ].…”

Biofilms as protective cocoons against biocides: from bacterial adaptation to One Health issues

“…The production of EPSs such as polysaccharides is one of the most frequent responses to biocide exposure. A large number of biocides have been shown to induce EPS production in different bacterial species through the activation of different pathways and regulators [32,35,36]. Polysaccharides are not the only component activitated during biocide exposure, as the overproduction of amyloid fibres has also been associated with the exposure of biofilms to different classes of biocides, e.g.…”