Antimicrobial susceptibility testing of bone and joint pathogens using isothermal microcalorimetry

Apmis, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 20, 2024

The rise in osteomyelitis and periprosthetic joint infections, combination with increasing life expectancy the prevalence of diabetes, underscores urgent need for rapid accurate diagnostic tools. Conventional culture‐based methods are often time‐consuming prone to false‐negatives, leading prolonged inappropriate antibiotic treatments. This study aims improve diagnostics by decreasing time detection an susceptibility result enable a targeted treatment using isothermal microcalorimetry (IMC). IMC measures heat flow real‐time, providing insights into bacterial metabolism without labeling. Using clinical isolates from bone assessing their response antibiotics through IMC, we demonstrated that could detect bacteria within 4 h determine antimicrobial profiles 2–22 (median 4.85, range 1.28–21.78). is significantly faster than traditional methods. A decision tree, based on susceptibility, accurately categorized pathogens, achieving high accuracy (74–100%), sensitivity (100%), specificity (65–100%). These findings suggest redefine infections potentially general, offering timely precise guidance, thereby improving patient outcomes reducing health care burdens. Further optimization validation needed fully integrate routine diagnostics.

Language: Английский

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A novel synthetic synovial fluid model for investigating biofilm formation and antibiotic susceptibility in prosthetic joint infections

Microbiology Spectrum, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 29, 2024

ABSTRACT There is growing evidence that bacteria encountered in prosthetic joint infections (PJIs) form surface-attached biofilms on prostheses, as well biofilm aggregates embedded synovial fluid and tissues. However, vitro models allowing the investigation of these assessment their antimicrobial susceptibility physiologically relevant conditions are currently lacking. To address this, we developed a synthetic (SSF2) model validated this by investigating growth, aggregate formation, using multiple PJI isolates belonging to various microorganisms. In study, 18 were included Staphylococcus aureus , coagulase-negative staphylococci, Cutibacterium acnes Streptococcus spp., Enterococcus Pseudomonas aeruginosa Escherichia coli Candida spp. Growth formation SSF2 evaluated light microscopy confocal laser scanning microscopy. The preventing concentration (BPC) minimal inhibitory (MBIC) antibiotics determined resazurin-based viability staining. BPC MBIC values compared conventional parameters (minimal bactericidal concentration) with approaches. medium allowed grow biofilm-like varying size shape between different species. For most cultured SSF2, reduced tested was observed when data obtained general media. These indicate could be valuable addition evaluate context PJI. IMPORTANCE Infections after replacement rare but can lead severe complications they difficult treat due ability pathogens prosthesis tissue fluid. This phenotype, combined microenvironment at infection site, substantially increases tolerance. Conventional typically use standard growth media, which do not consider site infection. By replacing media an vivo -like medium, such hope expand our knowledge aggregation addition, believe inclusion testing might able more accurately predict susceptibility, ultimately result better clinical outcome treatment.

Language: Английский

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Exploring aggregation genes in a P. aeruginosa chronic infection model

Journal of Bacteriology, Journal Year: 2024, Volume and Issue: 207(1)

Published: Dec. 11, 2024

Bacterial aggregates are observed in both natural and artificial environments. In the context of disease, have been isolated from chronic acute infections. Pseudomonas aeruginosa (Pa) contribute significantly to infections, particularly lungs people with cystic fibrosis (CF). Unlike large biofilm structures vitro, Pa CF sputum forms smaller (~10-1,000 cells), mechanisms behind their formation remain underexplored. This study aims identify genes essential unique aggregate a synthetic media (SCFM2). We cultured strain PAO1 SCFM2 LB, without mucin, used RNA sequencing (RNA-seq) differentially expressed genes. The presence mucin revealed 13 (DE) genes, predominantly downregulated, 40% encoding hypothetical proteins aggregates. Using high-resolution microscopy, we assessed ability mutants form Notably, no mutant exhibited completely planktonic phenotype. Instead, identified multiple spatial phenotypes described as "normal," "entropic," or "impaired." Entropic displayed tightly packed, raft-like structures, while impaired had loosely packed cells. Predictive modeling linked prioritized metabolic shifts, iron acquisition, surface modification, quorum sensing. Co-culture experiments wild-type further heterogeneity "rescue" some phenotypes, suggesting cooperative interactions during growth. enhances our understanding biology, specifically pathways aggregation CF-like Importantly, it provides insights for developing therapeutic strategies targeting aggregate-specific pathways. identifies (CF) sputum, filling critical gap specific biology. model (SCFM2) sequencing, key were identified, whose disruption led distinct through microscopy. addition cells either rescued phenotype increased heterogeneity, involved formation. research advances knowledge environments, offering valuable targeted against

Language: Английский

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Gram Negative Biofilms: Structural and Functional Responses to Destruction by Antibiotic-Loaded Mixed Polymeric Micelles

Microorganisms, Journal Year: 2024, Volume and Issue: 12(12), P. 2670 - 2670

Published: Dec. 23, 2024

Biofilms are a well-known multifactorial virulence factor with pivotal role in chronic bacterial infections. Their pathogenicity is determined by the combination of strain-specific mechanisms and biofilm extracellular matrix (ECM) protecting bacteria from host immune defense action antibacterials. The successful antibiofilm agents should combine antibacterial activity good biocompatibility capacity to penetrate through ECM. objective study elaboration biofilm-ECM-destructive drug delivery systems: mixed polymeric micelles (MPMs) based on cationic poly(2-(dimethylamino)ethyl methacrylate)-b-poly(ε-caprolactone)-b-poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA35-b-PCL70-b-PDMAEMA35) non-ionic poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO100-b-PPO65-b-PEO100) triblock copolymers, loaded ciprofloxacin or azithromycin. MPMs were applied 24 h pre-formed biofilms Escherichia coli Pseudomonas aeruginosa (laboratory strains clinical isolates). results showed that able destruct biofilms, viability experiments supported delivery. response two antibiotics revealed distinct patterns action. These registered level both cell-structural alterations (demonstrated scanning electron microscopy) interaction tissues (ex vivo infection model skin samples tests nitric oxide interleukin (IL)-17A production).

Language: Английский

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