Search Results (160)

Background/Objectives: Orthodontic tooth movement is a biological process involving coordinated bone resorption and formation in response to mechanical stimulation. The aim of this study was to evaluate the temporal changes in C-terminal telopeptide of type I collagen (CTX), procollagen type I N-terminal propeptide (PINP), and vitamin D-binding protein (VDBP) levels in gingival crevicular fluid (GCF) and saliva during fixed orthodontic treatment, as well as to assess the relationships among these biomarkers. Methods: The study included a total of 27 systemically and periodontally healthy individuals comprising 14 males and 13 females. Clinical periodontal parameters were assessed at three time points: before treatment (T0), at 24–48 h (T1), and on day 40 (T2). GCF and saliva samples were collected at the same time points. Levels of CTX, PINP and VDBP in GCF and saliva were quantified using enzyme-linked immunosorbent assay. The data were analyzed using both parametric and non-parametric statistical tests. Temporal changes across the three time points were evaluated using mixed-effects models, differences between GCF and saliva biomarker levels were assessed using paired tests, and correlations were examined using Spearman correlation analysis. Results: GCF and salivary CTX levels demonstrated a significant increase from T0 to T1, while PINP levels exhibited a substantial rise from T1 to T2 (p < 0.001). Levels of VDBP in both GCF and saliva did not demonstrate significant temporal changes (p > 0.05). Higher VDBP levels in both fluids were found to be negatively associated with increases in CTX and positively associated with increases in PINP (p < 0.05). Furthermore, salivary CTX and VDBP levels exhibited a consistent increase compared to those measured in GCF at all time points (p < 0.05). Conclusions: Fixed orthodontic forces elicit sequential resorptive and formative responses in both GCF and saliva. The potential of VDBP to function as a local modulator is indicated, with the capacity to influence the balance between osteoclastic and osteoblastic activity. The evaluation of these biomarkers in non-invasive biological samples may offer a valuable approach for monitoring bone metabolism throughout orthodontic treatment. Full article

Background: Impaired bone health is a recognized complication of type 1 diabetes. This study evaluated the effects of low-carbohydrate (LC) and Mediterranean (MED) diets on bone turnover markers in adolescents and young adults. Methods: In a 24-week randomized controlled trial, 40 individuals aged 12–21 years, with type 1 diabetes, were assigned to an LC or MED intervention (20 participants per group). C-terminal telopeptide (CTX) and procollagen type 1 N-terminal propeptide (P1NP) were measured at baseline and 24 weeks. Results: The groups had similar baselines. At 24 weeks, the between-group difference in delta glucose time in range was not statistically significant; median daily carbohydrate intake was 86 g (68–95) in LC and 130 g (102–173) in MED (p < 0.001). Comparing LC to MED, the median BMI z-score was lower (−0.1 [−0.3 to −0.1] vs. 0.0 [−0.1 to −0.1], p = 0.10), and calcium (p = 0.035) and magnesium intakes (p = 0.030) were lower. These associations did not remain statistically significant after false-discovery-rate correction. The median-adjusted alkaline phosphatase level decreased significantly in the LC group (p = 0.009). The median CTX changed following LC from 395 pg/mL (232–591) to 423 pg/mL (289–591) (p = 0.278); and following MED, from 357 pg/mL (244–782) to 296 pg/mL (227–661) (p = 0.245). P1NP changed in LC from 95 ng/mL (68–112) to 88 ng/mL (62–97) (p = 0.056) and in MED from 76 ng/mL (54–198) to 71 ng/mL (55–122) (p = 0.594). Conclusions: Exploratory analyses of bone turnover markers showed insignificant differences following LC and MED diets. Full article

Background: There are many methods of identifying microbial resistance to therapeutic agents; however, they can generally be classified into two main categories: phenotypic and genotypic. The study aims to determine drug sensitivity and to analyze the correlation between the results obtained from cultures on commercial chromogenic media Brilliance^TM CRE (OXOID) and Brilliance^TM ESBL (OXOID) and the occurrence of specific resistance genes carbapenemase (IMP, NDM, VIM, KPC, OXA), ESBL β-lactamase (TEM, SHV, CTX-M), and AmpC (CMY, DHA), which will be used in drug sensitivity tests. Methods: The present study used bacteria, including Klebsiella pneumoniae, Acinetobacter baumannii, and Escherichia coli, obtained from patients hospitalized in military hospitals in Poland. All strains were plated on the commercial chromogenic media and subjected to antimicrobial susceptibility testing. Additionally, molecular assays detecting three main classes according to the mechanism of action, enzyme type carbapenemase (IMP, NDM, VIM, KPC, OXA), ESBL β-lactamase (TEM, SHV, CTX-M), and AmpC (CMY, DHA) were performed using the real-time PCR method. Results: The results of the studies indicate the presence of carbapenemases and ESBL genes. Among K. pneumoniae strains, the dominant gene was CTX-M-15 (88.89%), followed by the SHV (84.12%), NDM (46.03%), TEM (41.26%), KPC (34.92%), and OXA-48 (19.04%). In contrast, A. baumanii was dominated by carbapenemases from the OXA family (OXA-51 in 96.00% and OXA-24/40 in 84.00%). E. coli exhibits a high prevalence of CTX-M-15 (53.85%), TEM (46.15%), NDM (38.46%), and CMY-2 (30.77%). It was observed that the CTX-M-15 gene was commonly co-identified with SHV (n = 43). All tested strains grew on chromogenic Brilliance^TM CRE medium. In the case of Brilliance^TM ESBL medium, the genes determining the resistance mechanism were detected in 41.7% for A. baumannii, 53.8% for E. coli, and 100% for K. pneumoniae. Chromogenic media perfectly differentiate strains to species. A moderate positive correlation of the occurrence of the antibiotic resistance genes was observed for OXA-51 and OXA-24/40 genes, which were resistant to meropenem (rho = 0.45, p < 0.001). K-means cluster analysis performed on integrated genotype–phenotype data allowed for the identification of three distinct clusters characterized by distinct resistance gene profiles. These results demonstrate that selective agar media enable faster identification compared to other conventional techniques; however, the obtained results should be confirmed by other validated phenotypic methods, and, if possible, by a molecular assay. Full article

Background: The juvenile-pubertal period is a critical window for linear growth and bone mass accumulation. This study investigated the joint effects of folic acid (FA) and colostrum basic protein (CBP)-fortified milk powder on growth, bone health, and metabolic safety in juvenile mice. Methods: Three-week-old C57BL/6J mice (n = 120) were acclimatized for 1 week and then randomly assigned to three isocaloric diet groups for an 8-week intervention starting at 4 weeks of age: Control (AIN-93M), Milk (AIN-93M + FA/CBP-fortified milk powder), and Positive Control (AIN-93G). Body length and weight were measured twice weekly. Bone microarchitecture was assessed by micro-computed tomography, and bone remodeling was evaluated through histology and serum biomarkers. The GH–IGF-1 axis and related metabolic parameters were also assessed. Results: FA–CBP–fortified milk powder significantly accelerated linear growth at intervention week 2, with body length higher in the Milk group than in the Control group (p < 0.01). After 8 weeks, the Milk group showed improved trabecular bone mass and microarchitecture compared with Control, especially in males (p < 0.01). Bone remodeling was transiently elevated at intervention week 4, as indicated by higher serum osteocalcin and CTX-I, and by increased osteoclast and cartilage matrix formation versus Control (p < 0.05). The GH–IGF-1 axis was also temporarily activated at week 4, with elevated serum GH and IGF-1/IGFBP-3 ratio compared with Control (p < 0.05). These skeletal benefits occurred without excess weight gain or adverse metabolic effects compared with Control (all p > 0.05). Conclusions: FA-CBP-fortified milk significantly enhanced linear growth during puberty and improved bone mass and microstructure in early adulthood. These skeletal benefits are consistent with the transient activation of the GH–IGF-1 axis. Importantly, no adverse metabolic effects were detected from early intervention through adulthood, supporting its potential application in growth-promoting nutritional strategies. Full article

Objective: The aim was to evaluate the effects of two high-resistance training (RT) protocols combined with curcumin supplementation on antioxidant capacity, systemic inflammation, bone and muscle health, and body composition. Methods: Eighty-one apparently healthy older adults [(68.2 ± 4.6 years (57% women); BMI 26.4 ± 4.8 kg/m²; minimally active according to IPAQ] were randomly allocated to accentuated eccentric (Aecc), maximal strength (Max), or a non-training control (C). Additionally, participants received either a bio-optimized curcumin formulation (Cur) or a placebo (Pla), resulting in six study groups: Aecc-Cur, Aecc-Pla, Max-Cur, Max-Pla, C-Cur, and C-Pla. Participants underwent pre- and post-intervention assessments of oxidative stress, inflammation, and bone health parameters, whole-body composition, and muscle function. Aecc and Max performed six familiarization sessions and a 16-week intervention. Participants in the curcumin groups received 500 mg/day of a bio-optimized curcumin formulation (Cursol^TM; 2 × 250 mg capsules per day, corresponding to 10.50 mg/day of curcumin) throughout the intervention. Data were analyzed using three-way repeated-measures ANOVA/ANCOVA with time (pre–post) as the within-subject factor and training group and supplementation as between-subject factors, with Least Significant Difference post hoc comparisons and effect sizes (Hedges’ g, ηp²) reported, and the significance level set at p < 0.05. Results: Aecc was the most effective in improving antioxidant capacity (glutathione; F = 25.57, p ≤ 0.001, ηp² = 0.262) and bone biomarkers (serum-procollagen type I N-propeptide—P1NP, p ≤ 0.001, ηp² = 0.504; serum beta C-terminal cross-linked telopeptide of type I collagen—β-CTX—p = 0.022, ηp² = 0.074, and their ratio—P1NP/β-CTX—p ≤ 0.001, ηp² = 0.605). Interleukin-6 (IL-6) decreased more in Aecc (p ≤ 0.001, ηp² = 0.584) and tumor necrosis factor-alpha (TNF-α) in Max (p ≤ 0.001, ηp² = 0.471). Both groups similarly improved body composition and muscle function. Bone mineral density was generally unchanged. Overall, curcumin supplementation enhanced the benefits of high-RT programs (further glutathione increase in Aecc [Hedge’s g: 0.49]; IL-6 decrease in both modalities [Hedge’s g: 0.48–1.27]; decrease in TNF-α in controls [Hedge’s g: 0.47]; better outcomes in P1NP/β-CTX in all groups [Hedge’s g: 0.46–1.46]; among others). Conclusions: Aecc is recommended for supporting antioxidant capacity and bone health, while the choice between Aecc and Max may depend on the individual’s inflammatory profile. Curcumin supplementation further amplifies the benefits of both RT protocols across most outcome variables. Full article

Background: Rapid molecular detection of antimicrobial resistance (AMR) can shorten time to effective therapy in complicated urinary tract infections (cUTI), but the ability of gene presence and quantitative PCR signal (Ct, and ΔCt = Ct_marker − IC_Ct) to predict phenotypic non-susceptibility and clinical outcomes requires rigorous evaluation. We analyzed marker-level concordance, Ct→MIC relationships, and the clinical impact pathway in the randomized NCT06996301 trial. Methods: Marker–phenotype concordance metrics (sensitivity, specificity, PPV, NPV, LR+, LR−, κ) were computed for selected marker × species strata with stable sample sizes. Mixed-effects models (log₂[MIC] ~ ΔCt_marker + IC_Ct + collection_method + prior_abx + (1|site)) assessed quantitative Ct→MIC associations. ROC analyses evaluated ΔCt discrimination of phenotypic non-susceptibility. A pre-specified sensitivity analysis included smaller strata (n ≤ 20) with bootstrap 95% confidence intervals for ΔCt slopes and AUCs. Clinical analyses compared PCR-guided (n = 193) versus culture-guided (n = 169) arms for time-to-antibiotic and treatment success using adjusted logistic regression and causal mediation (time-to-antibiotic as mediator; bootstrap inference). Results: High genotype–phenotype concordance was observed for canonical markers (e.g., bla_CTX-M in E. coli: sensitivity 0.94 [95% CI 0.88–0.97], specificity 0.995 [95% CI 0.990–0.998], κ ≈ 0.93). Mixed models showed modest but significant Ct→MIC associations for select markers (e.g., bla_CTX-M in E. coli: ΔCt slope −0.15 [95% CI −0.27 to −0.02], p = 0.015). The sensitivity analysis (n ≤ 20 strata) confirmed consistent negative directions, with robust bootstrap CIs excluding zero for qnrS (E. coli), tetM (E. coli), blaNDM (Klebsiella), and qnrS (Proteus). ROC AUCs for ΔCt prediction of non-susceptibility ranged from 0.62 to 0.81 (95% CIs ≈ 0.47–0.97). Clinically, PCR guidance shortened median time to antibiotic initiation (20 h vs. 52 h) and increased treatment success (88.1% vs. 78.1%; adjusted OR 1.95 [95% CI 1.12–3.40], p = 0.018). Mediation analysis estimated that 63% (ACME 0.112 [95% CI 0.045–0.178], p = 0.002) of the treatment success benefit was mediated through earlier antibiotic initiation. Conclusions: Binary detection of high-impact AMR genes by multiplex PCR reliably predicts phenotypic non-susceptibility and accelerates effective therapy when integrated with stewardship workflows. Quantitative PCR (ΔCt) provides modest but reproducible information about MIC magnitude and may flag heteroresistant subpopulations. A pragmatic implementation model combining rapid PCR with conventional culture is recommended to optimize clinical benefit while retaining isolate recovery for definitive AST. Full article

The present study aimed to determine the acute effects of high-intensity dynamic resistance training (HI-DRT) and whole-body electromyostimulation (WB-EMS) on markers of bone formation and resorption in young healthy women. Using a crossover design, 17 students of dentistry (26.5 ± 4.0 years, 21.5 ± 2.5 kg/m²) were randomly assigned to begin either with HI-DRT (five exercises, three sets to repetition maximum) or 20 min of non-superimposed, low-frequency (85 Hz), intermitted (6 s impulse/4 s impulse break) WB-EMS. The study outcome parameters were total Procollagen Type-1 N-Terminal Propeptide (P1NP) and Type-I Collagen Cross-Linked C-Telopeptide (CTX), which were sampled immediately prior to and 15 min post intervention. ANCOVA was applied to determine the main effects, i.e., differences in pre–post changes in CTX and P1NP between the interventions. No participant was lost to follow-up or reported adverse effects related to the exercises. Briefly, we observed significant differences (p = 0.019, d′ = 1.19) for changes in P1NP that were maintained in the HI-DRT (p = 0.446) and decreased in the WB-EMS group (p = 0.002). In contrast, we did not observe differences for HI-DRT- vs. WB-EMS-induced CTX changes (p = 0.509; d′ = 0.134). In summary, while HI-DRT provides significantly more favorable effects on bone formation markers compared to WB-EMS, the clinical significance of this finding in predicting the general effectiveness of an exercise protocol on bone strength remains to be determined. (Clinical trials.gov; registration date: 2025-02-06; ID: NCT06813092.) Full article

We adapt previous conceptual and numerical models of ciguateric food chains for the bioaccumulation of Pacific-ciguatoxin-1 (P-CTX-1) to a general model for bioaccumulation of P-CTX3C by parrotfish (Scarus frenatus, S. niger, and S. psittacus) that feed by scraping turf algae, and surgeonfish (Naso unicornis) that mostly feed on macroalgae. We also include the Indian Ocean parrotfish Chlorurus sordidus as a model for an excavator feeding parrotfish and include comparisons with the detritivorous surgeonfish Ctenochaetus striatus that brush-feeds on turf algae. Our food chain model suggests that, of the Gambierdiscus and Fukuyoa species so far analysed for ciguatoxin (CTX) production from the Pacific, only G. polynesiensis produces sufficient P-CTX3C to consistently produce parrotfish or N. unicornis with poisonous flesh. Our model suggests that insufficient CTX would accumulate into the flesh of parrotfish or N. unicornis to become poisonous from ingesting benthic dinoflagellates producing ≤0.03 pg P-CTX3C eq./cell, except from extended feeding times on high-density blooms and in the absence of significant depuration of CTX. Apart from G. polynesiensis, only G. belizeanus and possibly G. silvae and G. australes are thought to produce >0.03 pg P-CTX3C eq./cell in the Pacific. However, with relatively low maximum concentrations of ≤0.1 pg P-CTX3C eq./cell it is likely that their contribution is minimal. Our model also suggests that the differences between the area of turf algae grazed by parrotfish and similar sized C. striatus results in greater accumulation of CTX by this surgeonfish. This makes C. striatus a higher ciguatera risk than similar sized parrotfish, either directly for human consumption or as prey for higher trophic level fishes, consistent with poisoning data from Polynesia. It also suggests the possibility that C. striatus could bioaccumulate sufficient CTX to become mildly poisonous from feeding on lower toxicity Gambierdiscus or Fukuyoa species known to produce ≥0.02 P-CTX3C eq./cell. This indicates the potential for at least two food chain pathways to produce ciguateric herbivorous fishes, depending on the CTX concentrations produced by resident Gambierdiscus or Fukuyoa on a reef and the grazing capacity of herbivorous fish. However, only G. polynesiensis appears to produce sufficient P-CTX3C to consistently accumulate in food chains to produce higher trophic level fishes that cause ciguatera in the Pacific. We incorporate CTX depuration into our model to explore scenarios where mildly poisonous parrotfish or N. unicornis ingest CTX at a rate that is balanced by depuration to estimate the Gambierdiscus/Fukuyoa densities and CTX concentrations required for these fish to remain poisonous on a reef. Full article

In this study, sucrase A (SacA) from Bacillus subtilis was successfully displayed on the outer membrane of Escherichia coli via fusion with the AIDA-I autotransporter from E. coli. The pAIDA-sacA plasmid was constructed by fusing sacA with the ctxB signal sequence and the β-barrel domain of aida gene, enabling surface expression under both aerobic and anaerobic conditions. Functional expression of AIDA–SacA was confirmed by the appearance of reducing sugars in enzymatic assays of sucrose hydrolysis and by acid production on phenol red agar. Structural prediction suggested correct localisation of the catalytic domain on the extracellular surface. Enzymatic characterisation revealed that AIDA-SacA exhibits optimal activity at 40 °C and pH 7. The calculated Km for sucrose was 1.18 mM, while the corresponding Vmax was 2.32 U mL⁻¹. Thermal stability assays showed that the enzyme retained over 80% of its activity after 60 min at 45 °C, indicating notable resistance to moderate temperatures. Metal ion assays indicated that K⁺ enhanced enzymatic activity, while Zn²⁺, Cu²⁺, and Mg²⁺ were inhibitory. SDS-PAGE analysis confirmed the expression of the recombinant fusion protein, with a distinct band at approximately 114 kDa corresponding to the expected size. These results demonstrate the feasibility of employing the AIDA-I system for the surface display of SacA in E. coli, providing a functional platform for future applications in whole-cell biocatalysis. Full article

Background/Objectives: Cutibacterium acnes is increasingly recognized as a relevant pathogen in orthopaedic implant-associated infections, yet treatment strategies remain largely empirical. With rising antimicrobial resistance and scarce data on drug interactions, optimizing targeted therapies is essential. This preclinical study investigated the efficacy and synergism of vancomycin (VA), gentamicin (GEN), and ceftriaxone (CTX) against two clinical phylotype IB strains from orthopaedic infections and the reference strain C. acnes ATCC 6919, using both in vitro and in vivo models. Methods: Minimum inhibitory concentrations (MICs) were determined using broth microdilution following BrCAST guidelines. Synergistic activity was assessed using the checkerboard assay and interpreted via fractional inhibitory concentration indices (FICIs). The in vivo efficacy of antibiotic combinations with bioactive glass S53P4 (BAG) was evaluated in the Galleria mellonella infection model. Results: All C. acnes strains exhibited uniformly low MICs. Synergistic activity was observed for CTX combined with GEN in strain 2 (FICI range 0.25–0.37), while partial synergy was detected for CTX with GEN in strain 1 (FICI ≈ 0.56–0.63), and for CTX combined with VA in the ATCC strain (FICI = 0.66). All other combinations demonstrated indifferent interactions. In the G. mellonella model, a high bacterial inoculum (OD₆₀₀ of 3.0) was needed to establish an infection. For all strains tested, the use of antibiotics in combination with BAG improved larval survival. For the clinical strains, the combination of CTX + GEN + BAG and BAG alone demonstrated greater efficacy in promoting larval survival. Conclusions: Acombination of a cephalosporin with an aminoglycoside, particularly when incorporated into a biomaterial matrix, enhances antimicrobial activity against both clinical and reference strains of C. acnes. Full article

The emergence of extensively drug-resistant (XDR) foodborne pathogens poses grave threats to food safety. This study characterizes the genome of an XDR Salmonella Kentucky isolate (Sal23C1) co-harboring cfr, mcr-1 and tet(A) from Shanghai chicken meat in 2022, which was the only isolate co-harboring these three key resistance genes among 502 screened Salmonella isolates. Genomic analysis revealed that the multidrug resistance gene cfr, which confers resistance to phenicols, lincosamides, oxazolidinones, pleuromutilins and streptogramin A, was identified within a Tn3-IS6-cfr-IS6 structure on the transferable plasmid p3Sal23C1 (32,387 bp), showing high similarity to the Citrobacter braakii plasmid pCE32-2 (99% coverage, 99.98% identity). Concurrently, the mcr-1 gene resided in a pap2-mcr-1 structure on the transferable IncI2 plasmid p2Sal23C1 (63,103 bp). Notably, both genes could be co-transferred to recipient bacteria via conjugative plasmids at frequencies of (1.15 ± 0.98) × 10⁻⁶. Furthermore, a novel ~79 kb multidrug resistance region (MRR) chromosomally inserted at the bcfH locus was identified, carrying fosA3, mph(A), rmtB, qnrS1 and bla_CTX-M-55. Additionally, a novel Salmonella Genomic Island 1 variant (SGI1-KI) harbored aadA7, qacEΔ1, sul1 and the tet(A) variant. The acquisition of these antibiotic resistance genes in this isolate enhanced bacterial resistance to 21 antimicrobials, including resistance to the critical last-resort antibiotics tigecycline and colistin, which left virtually no treatment options for potential infections. Taken together, this is the first comprehensive genomic report of an XDR poultry-derived Salmonella Kentucky isolate co-harboring cfr, mcr-1 and the tet(A) variant. The mobility of these resistance genes, facilitated by IS6 elements and conjugative plasmids, underscores significant public health risks associated with such isolates in the food chain. Full article

An outbreak characterized by clinical signs of diarrhea and paralysis, occasionally progressing to fatal outcomes, occurred at an ostrich breeding facility. Conventional antibiotic treatments proved ineffective. To investigate the etiology of the disease, brain and liver specimens were collected for diagnostic analysis. An Escherichia coli (E. coli) isolate, designated strain HZDC01, was obtained from cerebral tissues, and whole-genome sequencing was performed for genomic characterization. Genomic analysis revealed that the chromosomal DNA harbors numerous resistance genes, conferring multidrug resistance through complex mechanisms. Furthermore, a p0111-type plasmid carrying the bla_CTX-M-55 gene and an IncX1-type plasmid harboring rmtB, sul1, APH(6)-Id, tet(A), AAC(3)-IIc, aadA2, bla_TEM-1B, and floR genes were identified. These plasmids carry numerous mobile genetic elements that can disseminate via horizontal gene transfer, thereby amplifying the risk of resistance-gene spread within bacterial populations. Additionally, the ibeB and ibeC genes, which encode proteins involved in the invasion of brain microvascular endothelial cells, were identified. These genes may facilitate E. coli penetration of the blood–brain barrier, potentially leading to meningitis and posing a life-threatening risk to the host. This is the first report of the isolation and characterization of extended-spectrum beta-lactamase E. coli from the brain of an ostrich with paralysis. The findings provide valuable genomic insights into the antimicrobial resistance profiles and pathogenic mechanisms of ostrich-derived E. coli isolates. Full article

Background and Objectives: Osteoarthritis (OA) is a degenerative joint disease involving inflammation, oxidative stress, and extracellular matrix (ECM) degradation, leading to cartilage damage and joint dysfunction. This study aimed to evaluate the chondroprotective effects of intra-articular hydrolyzed collagen in a rat model of knee OA using a dual-compartment biochemical and histological approach. Materials and Methods: Twenty male Sprague-Dawley rats underwent ACL transection to induce osteoarthritis and were randomly assigned to receive intra-articular hydrolyzed collagen or saline once weekly for three weeks. At six weeks, knee joints were evaluated histologically using the Mankin score. Synovial fluid and cartilage homogenates were analyzed via enzyme-linked immunosorbent assay (ELISA) for cytokines, cartilage degradation markers, and oxidative stress indicators. Results: The collagen-treated group demonstrated significantly lower Mankin scores. Levels of pro-inflammatory cytokines, interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), as well as cartilage degradation markers, matrix metalloproteinase-13 (MMP-13), C-terminal crosslinked telopeptide of type II collagen (CTX-II), and cartilage oligomeric matrix protein (COMP), were significantly reduced (p < 0.05). Additionally, oxidative stress indicators including inducible nitric oxide synthase (iNOS), total oxidant status (TOS), and oxidative stress index (OSI) were decreased, while total antioxidant status (TAS) was increased in both synovial fluid and cartilage homogenates (p < 0.05). Conclusions: Intra-articular hydrolyzed collagen reduced inflammation, oxidative stress, and extracellular matrix (ECM) degradation, indicating potential chondroprotective effects across both synovial and cartilage compartments. Full article

Background/objectives: Proteus mirabilis is a frequent causative agent of urinary and wound infections in both community and hospital settings. It develops resistance to expanded-spectrum cephalosporins (ESCs) due to the production of extended-spectrum β-lactamases (ESBLs) or plasmid-mediated AmpC β-lactamases (p-AmpCs). Recently, carbapenem-resistant isolates of P. mirabilis emerged due to the production of carbapenemases, mostly belonging to Ambler classes B and D. Here, we report an outbreak of infections due to carbapenem-resistant P. mirabilis that were observed in a psychiatric hospital in Zagreb, Croatia. The characteristics of ESBL and carbapenemase-producing P. mirabilis isolates, associated with an outbreak, were analyzed. Materials and methods: The antibiotic susceptibility testing was performed by the disk-diffusion and broth dilution methods. The double-disk synergy test (DDST) and inhibitor-based test with clavulanic and phenylboronic acid were applied to screen for ESBLs and p-AmpCs, respectively. Carbapenemases were screened by the modified Hodge test (MHT), while carbapenem hydrolysis was investigated by the carbapenem inactivation method (CIM) and EDTA-carbapenem-inactivation method (eCIM). The nature of the ESBLs, carbapenemases, and fluoroquinolone-resistance determinants was investigated by PCR. Plasmids were characterized by PCR-based replicon typing (PBRT). Selected isolates were subjected to molecular characterization of the resistome by an Inter-Array Genotyping Kit CarbaResisit and whole-genome sequencing (WGS). Results: In total, 20 isolates were collected and analyzed. All isolates exhibited resistance to amoxicillin alone and when combined with clavulanic acid, cefuroxime, cefotaxime, ceftriaxone, cefepime, imipenem, ceftazidime–avibactam, ceftolozane–tazobactam, gentamicin, amikacin, and ciprofloxacin. There was uniform susceptibility to ertapenem, meropenem, and cefiderocol. The DDST and combined disk test with clavulanic acid were positive, indicating the production of an ESBL. The MHT was negative in all except one isolate, while the CIM showed moderate sensitivity, but only with imipenem as the indicator disk. Furthermore, eCIM tested positive in all of the CIM-positive isolates, consistent with a metallo-β-lactamase (MBL). PCR and sequencing of the selected amplicons identified VIM-1 and VIM-4. The Inter-Array Genotyping Kit CarbaResist and WGS identified β-lactam resistance genes bla_VIM, bla_CTX-M-15, and bla_TEM genes; aminoglycoside resistance genes aac(3)-IId, aph(6)-Id, aph(3″)-Ib, aadA1, armA, and aac(6′)-IIc; as well as resistance genes for sulphonamides sul1 and sul2, trimethoprim dfr1, chloramphenicol cat, and tetracycline tet(J). Conclusions: This study revealed an epidemic spread of carbapenemase-producing P. mirabilis in two wards in a psychiatric hospital. Due to the extensively resistant phenotype (XDR), therapeutic options were limited. This is the first report of carbapenemase-producing P. mirabilis in Croatia. Full article

Klebsiella pneumoniae is a major public health concern due to its role in Gram-negative bacteremia, which leads to high mortality and increased healthcare costs. This study characterizes phenotypic and genomic features of K. pneumoniae isolates from clinical samples in Karachi, Pakistan. Among 507 isolates, 213 (42%) were carbapenem-resistant based on disk diffusion and MIC testing. Urine (29.7%) and blood (28.3%) were the most common sources, with infections predominantly affecting males (64.7%) and individuals aged 50–70 years. Colistin was the only antibiotic showing consistent activity against these isolates. The whole-genome sequencing of 24 carbapenem-resistant K. pneumoniae (CR-KP) isolates revealed bla_NDM-5 (45.8%) as the dominant carbapenemase gene, followed by bla_NDM-1 (12.5%) and bla_OXA-232 (54.2%). Other detected bla_OXA variants included bla_OXA-1, bla_OXA-4, bla_OXA-10, and bla_OXA-18. The predominant beta-lactamase gene was bla_CTX-M-15 (91.6%), followed by bla_CTX-M-163, bla_CTX-M-186, and bla_CTX-M-194. Sequence types ST147, ST231, ST29, and ST11 were associated with resistance. Plasmid profiling revealed IncR (61.5%), IncL (15.4%), and IncC (7.7%) as common plasmid types. Importantly, resistance was driven not only by acquired genes but also by chromosomal mutations. Porin mutations in OmpK36 and OmpK37 (e.g., P170M, I128M, N230G, A217S) reduced drug influx, while acrR and ramR mutations (e.g., P161R, G164A, P157*) led to efflux pump overexpression, enhancing resistance to fluoroquinolones and tigecycline. These findings highlight a complex resistance landscape driven by diverse carbapenemases and ESBLs, underlining the urgent need for robust antimicrobial stewardship and surveillance strategies. Full article