Zirconyl Clindamycinphosphate Antibiotic Nanocarriers for Targeting Intracellular Persisting Staphylococcus aureus.
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ABSTRACT:
SUBMITTER: Heck JG
PROVIDER: S-EPMC6644946 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Bacterial persister cells are phenotypic variants that exhibit a transient non-growing state and antibiotic tolerance. Here we provide in vitro evidence of Staphylococcus aureus persisters within infected host cells. We show that the bacteria surviving antibiotic treatment within host cells are persisters, displaying biphasic killing and reaching a uniformly non-responsive, non-dividing state when followed at the single-cell level. This phenotype is stable but reversible upon antibiotic removal. Intracellular S. aureus persisters remain metabolically active, but display an altered transcriptomic profile consistent with activation of stress responses, including the stringent response as well as cell-wall stress, SOS and heat-shock responses. These changes are associated with multidrug tolerance after exposure to a single antibiotic. We hypothesize that intracellular S. aureus persisters may constitute a reservoir for relapsing infection, and could contribute to therapeutic failures.
2020-03-25 | GSE139659 | GEO
Project description:BackgroundThe two major indications for tonsillectomy are recurrent tonsillitis (RT) and peritonsillar abscess (PTA). Unlike PTAs, which are primarily treated surgically, RT is often cured by tonsillectomy only after a series of failed drug therapy attempts. Although the bacteriological background of RT has been studied, the reason for the lack of success of conservative therapeutic approaches is not well understood.MethodsIn a prospective study, tonsil specimens from 130 RT patients and 124 PTA patients were examined for the presence of extra- and intracellular bacteria using antibiotic protection assays. Staphylococcus aureus isolates from RT patients were characterized by pulsed-field gel electrophoresis (PFGE), spa-typing and MSCRAMM-gene-PCR. Their ability for biofilm formation was tested and their cell invasiveness was confirmed by a flow cytometric invasion assay (FACS), fluorescent in situ hybridization (FISH) and immunohistochemistry.FindingsS. aureus was the predominant species (57.7%) in RT patients, whereas Streptococcus pyogenes was most prevalent (20.2%) in PTA patients. Three different assays (FACS, FISH, antibiotic protection assay) showed that nearly all RT-associated S. aureus strains were located inside tonsillar cells. Correspondingly, the results of the MSCRAMM-gene-PCRs confirmed that 87% of these S. aureus isolates were invasive strains and not mere colonizers. Based upon PFGE analyses of genomic DNA and on spa-gene typing the vast majority of the S. aureus isolates belonged to different clonal lineages.ConclusionsOur results demonstrate that intracellular residing S. aureus is the most common cause of RT and indicate that S. aureus uses this location to survive the effects of antibiotics and the host immune response. A German translation of the Abstract is provided as supplementary material (Abstract S1).
| S-EPMC2830486 | biostudies-literature
Project description:Bacterial persister cells are phenotypic variants that exhibit a transient non-growing state and antibiotic tolerance. Here, we provide in vitro evidence of Staphylococcus aureus persisters within infected host cells. We show that the bacteria surviving antibiotic treatment within host cells are persisters, displaying biphasic killing and reaching a uniformly non-responsive, non-dividing state when followed at the single-cell level. This phenotype is stable but reversible upon antibiotic removal. Intracellular S. aureus persisters remain metabolically active but display an altered transcriptomic profile consistent with activation of stress responses, including the stringent response as well as cell wall stress, SOS and heat shock responses. These changes are associated with multidrug tolerance after exposure to a single antibiotic. We hypothesize that intracellular S. aureus persisters may constitute a reservoir for relapsing infection and could contribute to therapeutic failures.
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Project description:Intracellular survival of pathogenic bacteria leads to high chances of bacterial persistence and relapse in the bacteria-infected host. However, many antibiotics fail to clear the intracellular bacteria due to their low internalization by cells. In order to increase delivery of antibiotics in cells and eliminate intracellular bacteria, we developed antibiotic-derived lipid nanoparticles. First, we synthesized antibiotic-derived lipid conjugates using two widely used antibiotics including penicillin G (PenG) and levofloxacin (Levo). Then, we formulated them into antibiotic-derived lipid nanoparticles and evaluated their antibacterial effects. We found that penicillin G derived phospholipid nanoparticles (PenG-PL NPs) were able to enhance cellular uptake of penicillin G as compared with free penicillin G and eliminate up to 99.9998% of ~108.5 intracellular methicillin sensitive Staphylococcus aureus (S. aureus) in infected A549 cells, a lung epithelial cell line. The PenG-PL NPs showed the potential for inhibiting intracellular S. aureus and are promising to be further studied for in vivo antibacterial applications.
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Project description:Chronic staphylococcal osteomyelitis can persist for long time periods causing bone destruction. The ability of Staphylococcus aureus to develop chronic infections is linked to its capacity to invade and replicate within osteoblasts and osteocytes and to switch to a dormant phenotype called small colony variants. Recently, osteocytes were described as a main reservoir for this pathogen in bone tissue. However, the mechanisms involved in the persistence of S. aureus within these cells are still unknown. Here, we investigated the interaction between S. aureus and osteoblasts or osteocytes during infection. While osteoblasts are able to induce a strong antimicrobial response and eliminate intracellular S. aureus, osteocytes trigger signals to recruit immune cells and enhance inflammation but fail an efficient antimicrobial activity to clear the bacterial infection. Moreover, we found that extracellular signals from osteocytes enhance intracellular bacterial clearance by osteoblasts. Even though both cell types express Toll-like receptor (TLR) 2, the main TLR responsible for S. aureus detection, only osteoblasts were able to increase TLR2 expression after infection. Additionally, proteomic analysis indicates that reduced intracellular bacterial killing activity in osteocytes is related to low antimicrobial peptide expression. Nevertheless, high levels of lipid mediators and cytokines were secreted by osteocytes, suggesting that they can contribute to inflammation. Taken together, our results demonstrate that osteocytes contribute to severe inflammation observed in osteomyelitis and represent the main niche for S. aureus persistence due to their poor capacity for intracellular antimicrobial response.
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Project description:The treatment of Staphylococcus aureus infections is impeded by the prevalence of MRSA and the formation of persisters and biofilms. Previously, we identified two celecoxib derivatives, Cpd36 and Cpd46, to eradicate MRSA and other staphylococci. Through whole-genome resequencing, we obtained several lines of evidence that these compounds might act by targeting the membrane protein translocase YidC2. Our data showed that ectopic expression of YidC2 in S. aureus decreased the bacterial susceptibility to Cpd36 and Cpd46, and that the YidC2-mediated tolerance to environmental stresses was suppressed by both compounds. Moreover, the membrane translocation of ATP synthase subunit c, a substrate of YidC2, was blocked by Cpd46, leading to a reduction in bacterial ATP production. Furthermore, we found that the thermal stability of bacterial YidC2 was enhanced, and introducing point mutations into the substrate-interacting cavity of YidC2 had a dramatic effect on Cpd36 binding via surface plasmon resonance assays. Finally, we demonstrated that these YidC2 inhibitors could effectively eradicate MRSA persisters and biofilms. Our findings highlight the potential of impeding YidC2-mediated translocation of membrane proteins as a new strategy for the treatment of bacterial infections.
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Project description:Many pathogens secrete effectors to hijack intracellular signaling regulators in host immune cells to promote pathogenesis. However, the pathogenesis of Staphylococcus aureus secretory effectors within host cells is unclear. Here, we report that Staphylococcus aureus secretes extracellular fibrinogen-binding protein (Efb) into the cytoplasm of macrophages to suppress host immunity. Mechanistically, RING finger protein 114, a host E3 ligase, mediates K27-linked ubiquitination of Efb at lysine 71, which facilitates the recruitment of tumor necrosis factor receptor associated factor (TRAF) 3. The binding of Efb to TRAF3 disrupts the formation of the TRAF3/TRAF2/cIAP1 (cellular-inhibitor-of-apoptosis-1) complex, which mediates K48-ubiquitination of TRAF3 to promote degradation, resulting in suppression of the inflammatory signaling cascade. Additionally, the Efb K71R mutant loses the ability to inhibit inflammation and exhibits decreased pathogenicity. Therefore, our findings identify an unrecognized mechanism of Staphylococcus aureus to suppress host defense, which may be a promising target for developing effective anti-Staphylococcus aureus immunomodulators.
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Project description:Intracellular Staphylococcus aureus persisters upon antibiotic exposure
| PRJNA586837 | ENA
Project description:Staphylococcus aureus is responsible for a substantial number of invasive infections globally each year. These infections are problematic because they are frequently recalcitrant to antibiotic treatment. Antibiotic tolerance, the ability of bacteria to persist despite normally lethal doses of antibiotics, contributes to antibiotic treatment failure in S. aureus infections. To understand how antibiotic tolerance is induced, S. aureus biofilms exposed to multiple anti-staphylococcal antibiotics were examined using both quantitative proteomics and transposon sequencing. These screens indicated that arginine metabolism is involved in antibiotic tolerance within a biofilm and led to the hypothesis that depletion of arginine within S. aureus communities can induce antibiotic tolerance. Consistent with this hypothesis, inactivation of argH, the final gene in the arginine synthesis pathway, induces antibiotic tolerance. Arginine restriction was found to induce antibiotic tolerance via inhibition of protein synthesis. In a mouse skin infection model, an argH mutant has enhanced ability to survive antibiotic treatment with vancomycin, highlighting the relationship between arginine metabolism and antibiotic tolerance during S. aureus infection. Uncovering this link between arginine metabolism and antibiotic tolerance has the potential to open new therapeutic avenues targeting previously recalcitrant S. aureus infections.
2024-07-10 | GSE267626 | GEO
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