Antibiotic Concentrations Research Articles

Tetracycline but not sulfamethazine inhibits early root growth of wild grassland species, while seed germination is hardly affected by either antibiotic

Seed germination and early growth of grassland species might be influenced by veterinary antibiotics that are extensively released into agricultural habitats. Therefore, we tested impacts of the commonly used antibiotics tetracycline and sulfamethazine, single and in mixture, on seed germination and seedling root growth of six typical species of temperate European grasslands (Carum carvi, Centaurea jacea, Galium mollugo, Plantago lanceolata, Silene latifolia, Dactylis glomerata). In standardised germination experiments, we assessed three germination variables (germination percentage, mean germination time, synchrony of germination) and one post-germination variable (seedling root length) under different environmentally realistic antibiotic concentrations (0.1, 1, 10 mg l−1 and a water control). While the germination variables were only irregularly and weakly affected by both antibiotics, seedling root length was strongly reduced by tetracycline, but not by sulfamethazine. Among the test species, D. glomerata was most sensitive to tetracycline with the average root length reduced up to 81 % in the 10 mg l−1 treatment. Its germination behaviour, however, was almost insensitive to the two antibiotics. Mixture effects were only shown in relation to the germination of single species, where the binary mixture produced effects but not the two single antibiotics or, conversely, effects of single antibiotics were lost in the mixture. These findings highlight the potential threat of plant regeneration from seed by veterinary antibiotics, particularly affecting early root growth and potentially influencing plant population growth in natural habitats.

Gene expression of psID gene in Pseudomonas aeruginosa isolated from clinical causes

One hundred clinical samples were collected from Baghdad hospitals including Teaching Laboratories Hospital, Medical City, Baghdad Teaching Hospital and Ghazi Hariri Hospital including burn infections, wound infections, urinary tract infections, otitis media from May 2022 to September 2022, The samples were identefied by microscopic, phenotypic and culturale on MacConkey agar and by biochemical tests including oxidase, catalase, citrate utilization test, triple sugar-iron test (TSI), gelatinase test, motility test and ornithine decarboxylation test. After diagnosis, we received 19 isolates of Pseudomonas aeruginosa . To detection biofilm genes used PslD gene, we all (19) isolates of Pseudomonas aeruginosa have these genes in percentage 100% with a molecular weight of 295 base pair. The gene expression study was done to evaluate the gene expression of the PslD biofilm gene using three concentrations of cefotaxim antibiotic (2, 4 and 8) μg/ml. Only two concentrations 2 and 8 μg/ml of cefotaxim had gene expression results of psID gene, 19.32 at RNA concentration when treated with 2 μg/ml of cefotaxim, 22.56 at RNA concentration when treated with 8 μg/ml of cefotaxim and undetermined at RNA concentration when treated with 4 μl/ml of cefotaxim.

Antimicrobial Sub-MIC induces Staphylococcus aureus biofilm formation without affecting the bacterial count

BackgroundBiofilm formation is an essential virulence factor that creates a highly protected growth mode for Staphylococcus aureus (S. aureus) to survive in any hostile environment. Antibiotic sub-minimal inhibitory concentration (sub-MIC) may modulate the biofilm formation ability of bacterial pathogens, thereby affecting bacterial pathogenesis and infection outcomes. Intense antimicrobial therapy to treat biofilm-associated infections can control the pathogenic infection aggravation but cannot guarantee its complete eradication.ObjectiveThis study aimed to assess the sub-MICs effect of 5 different antimicrobial classes on biofilm-forming capacity among Staphylococcus aureus clinical isolates using three different biofilm quantitation techniques.MethodsIn this study, the effects of 5 different antimicrobial agents, namely, azithromycin, gentamicin, ciprofloxacin, doxycycline, and imipenem, at sub-MICs of 12.5%, 25%, and 50% were tested on 5 different clinical isolates of S. aureus. The biofilms formed in the absence and presence of different antimicrobial sub-MICs were then assessed using the following three different techniques: the crystal violet (CV) staining method, the quantitative PCR (qPCR) method, and the spread plate method (SPM).ResultsBiofilm formation was significantly induced in 64% of the tested conditions using the CV technique. On the other hand, the qPCR quantifying the total bacterial count and the SPM quantifying the viable bacterial count showed significant induction only in 24% and 17.3%, respectively (Fig. 1). The difference between CV and the other techniques indicates an increase in biofilm biomass without an increase in bacterial growth. As expected, sub-MICs did not reduce the viable cell count, as shown by the SPM. The CV staining method revealed that sub-MICs of imipenem and ciprofloxacin had the highest significance rate (80%) showing an inductive effect on the biofilm development. On the other hand, doxycycline, azithromycin, and gentamicin displayed lower significance rates of 73%, 53%, and 47%, respectively.ConclusionExposure to sub-MIC doses of antimicrobial agents induces the biofilm-forming capacity of S. aureus via increasing the total biomass without significantly affecting the bacterial growth of viable count.

Monitoring concentration of quinolones in human serum by fluorescence and colorimetric analysis based on red carbon dots

Bacterial infections are common and predominant concern after surgical operation despite surgical techniques have improved significantly. Monitoring of antibiotics concentration can provide critical feedback in clinical treatment so as to achieve rapid and effective treatment and avoid bacterial resistance. Quinolones (QNs) are synthetic broad-spectrum antibiotics to treat bacterial infections. In this work, we developed a high-yield (50.67 %) red-emitting carbon dots (R-CDs) as fluorescence probe for sensing of three quinolone antibiotics, ofloxacin (OFL), gatifloxacin (GAT), and ciprofloxacin (CIP). R-CDs were prepared in 30 min using tartaric acid and o-phenylenediamine as precursors via an economical and efficient microwave-assisted method. At excitation of 339 nm, R-CDs show sensing performance towards OFL, GAT, CIP. Ofloxacin can be detected in the range of 0.25–30 μM with limit of detection (LOD) of 27.01 nM. Detection concentration range of gatifloxacin is between 0.25–40 μM and LOD is 23.73 nM. Ciprofloxacin can be detected in the range of 0.75–35 μM with LOD of 75.23 nM. A smartphone-assisted analysis platform was developed based on colorimetric phenomenon which applicable in three quinolones concentration monitoring in human serum. This research setup an efficient and promising therapeutic drug monitoring method for clinical treatment and widen the applications of carbon dots.

Use of local treatment in managing infections: Focus on antimicrobial locks, beads, and cement.

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. The purpose of this review is to describe important considerations with local antimicrobial therapies such as locks, beads, and cement for adjunctive infection management or prevention. Local delivery of antimicrobials with locks, beads, and cement has been used for infection management with retained devices in an effort to improve clinical success. However, their use has been controversial due to conflicting clinical data and logistical issues. Antimicrobial lock therapy (ALT) has been used for both adjunctive treatment and prevention of catheter-related bloodstream infections for certain pathogens and based on patient-specific scenarios. ALT has been a controversial method for sterilizing the catheter lumen by delivering high concentrations of antibiotics with or without heparin into the catheter for prolonged durations. Studies differ regarding the selection and concentrations of antibiotics, dwell duration, presence of heparin in the ALT, clinical outcomes/definitions, and use for prevention or treatment of catheter-related bloodstream infections. Antibiotic beads and cement have been used for various surgical procedures but are predominately considered in orthopedic surgeries. Despite the widespread use of the antibiotic-loaded bone cement in orthopedics, studies differ regarding the selection and concentrations of antibiotics, clinical outcomes/definitions, and use for prevention or treatment of infections. Although antimicrobial locks, beads, and cement are commonly used for adjunctive treatment or prevention of infections, more data are needed to support their use to provide clinical efficacy and safety with consistent antimicrobial selection and logistics.

Label-free single-cell antimicrobial susceptibility testing in droplets with concentration gradient generation.

Bacterial communities exhibit significant heterogeneity, resulting in the emergence of specialized phenotypes that can withstand antibiotic exposure. Unfortunately, the existence of subpopulations resistant to antibiotics often goes unnoticed during treatment initiation. Thus, it is crucial to consider the concept of single-cell antibiotic susceptibility testing (AST) to tackle bacterial infections. Nevertheless, its practical application in clinical settings is hindered by its inability to conduct AST efficiently across a wide range of antibiotics and concentrations. This study introduces a droplet-based microfluidic platform designed for rapid single-cell AST by creating an antibiotic concentration gradient. The advantage of a microfluidic platform is achieved by executing bacteria and antibiotic mixing, cell encapsulation, incubation, and enumeration of bacteria in a seamless workflow, facilitating susceptibility testing of each antibiotic. Firstly, we demonstrate the rapid determination of minimum inhibitory concentration (MIC) of several antibiotics with Gram-negative E. coli and Gram-positive S. aureus, which enables us to bypass the time-consuming bacteria cultivation, speeding up the AST in 3 h from 1 to 2 days of conventional methods. Additionally, we assess 10 clinical isolates including methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Staphylococcus aureus (MDRSA) against clinically important antibiotics for analyzing the MIC, compared to the gold standard AST method from the United States Clinical and Laboratory Standards Institute (CLSI), which becomes available only after 48 h. Furthermore, by monitoring single cells within individual droplets, we have found a spectrum of resistance levels among genetically identical cells, revealing phenotypic heterogeneity within isogenic populations. This discovery not only advances clinical diagnostics and treatment strategies but also significantly contributes to the field of antibiotic stewardship, underlining the importance of our approach in addressing bacterial resistance.

Rapid Quantification of Oxytetracycline Based on Fluorescence Enhancement Influenced by pH.

Accurate quantification of antibiotics in environmental samples is typically challenging due to the low antibiotic concentrations and the complexity of environmental matrices. This paper presents a fluorescence spectrometry method for determining oxytetracycline under alkaline conditions. The ionic distribution of the oxytetracycline solution was analyzed based on its dissociation constant. The dimethylamino group plays a crucial role in this method, as it promotes intramolecular charge transfer in the electronic excited state through its electron-donating capability with a lone electron pair. The presented method is straightforward, cost-effective, and holds potential for analyzing oxytetracycline in water sample after further investigation.

Exploring diflunisal as a synergistic agent against Staphylococcus aureus biofilm formation.

Staphylococcus aureus is a bacterial pathogen of considerable significance in public health, capable of inducing a diverse range of infectious diseases. One of the most notorious mechanisms used by S. aureus to survive and colonize the site of infection is its ability to form biofilms. Diflunisal, a non-steroidal anti-inflammatory drug (NSAID), is a known inhibitor of the Agr system in S. aureus, which is key in regulating biofilm formation. This study evaluated the effect of broad-spectrum antibiotics in combination with diflunisal on S. aureus biofilm density. Eight antibiotics were tested independently at different concentrations and in combination with diflunisal to assess their effect on S. aureus biofilm formation. When using the antibiotics alone and with diflunisal, a significant control effect on biofilm formation was observed (p < 0.05), irrespective of diflunisal presence, but did not achieve a complete biofilm growth inhibition. Over time, diflunisal influenced biofilm formation; however, such an effect was correlated with antibiotic concentration and exposure time. With amikacin treatments, biofilm density increased with extended exposure time. In the case of imipenem, doripenem, levofloxacin, and ciprofloxacin, lower doses and absence of diflunisal showed higher control over biofilm growth with longer exposure. However, in all cases, diflunisal did not significantly affect the treatment effect on biofilm formation. In the absence of antibiotics, diflunisal significantly reduced biofilm formation by 53.12% (p < 0.05). This study suggests that diflunisal could be a potential treatment to control S. aureus biofilms, but it does not enhance biofilm inhibition when combined with antibiotics.

Determination of phosphinothricin and paromomycin selective concentrations for obtaining transgenic spelt plants

Aim. To determine the selective concentrations of phosphinothricin and paromomycin for the selection of transgenic plants of spelt wheat. Methods. Shoot apical meristem culture, mature embryo culture, Agrobacterium-mediated genetic transformation. Results. Isolation and cultivation of shoot apical meristems of seedlings from three spelt genotypes and mature embryos from three other genotypes were carried out. A high frequency (from 80 to 100 %) of callus induction from explants was observed. It was shown that the addition of 5 mg/l of phosphinothricin or 100 mg/l of paromomycin to the culture medium almost completely inhibited plant regeneration compared to the control. After Agrobacterium-mediated genetic transformation of calli with a vector containing the phosphinothricin-N-acetyltransferase gene, regeneration of spelt shoots for one genotype was observed on a selective medium with 5 mg/l phosphinothricin. Conclusions. The selective concentrations of herbicide and antibiotic for obtaining transgenic spelt wheat plants with the corresponding marker genes are 5 mg/l for phosphinothricin and 100 mg/l for paromomycin.

Preliminary human health risk assessment of antibiotic exposures in human waste handling occupations

Exposure to biosolids in human waste handling occupations is associated with a risk for illness due to microbial infections. Although several years of exposure to biosolids might be hypothesized to be a prophylaxis against infection, the risks associated with infections from antibiotic-resistant organisms can also be a potential concern. Therefore, this study aimed to conduct a screening level risk assessment by deriving occupational exposure limits (OELs) characterizing the risks of adverse health effects among workers in human waste handling occupations with a focus on exposure to two pharmaceuticals commonly found in biosolids: ciprofloxacin (CIP) and azithromycin (AZ). Epidemiological and exposure studies of workers exposed to biosolids were identified through searches of major scientific databases. Screening OELs (sOELs) for these antibiotics were derived using a standardized methodology. The airborne concentrations of CIP and AZ antibiotics were determined using an exposure factors approach. The health-based exposure limits (i.e., sOELs) and the acceptable daily exposure (ADE) values for both of these antibiotics were derived as 80 μg/m3 and 12 μg/kg-day, respectively. An exposure factor approach suggested that inhalation route exposures to CIP and AZ are well below the sOELs and ADE daily doses, and likely too low to cause direct adverse health effects through antibiotic inhalation. A critical review of epidemiological studies on different occupations handling biosolids showed that the workers in industries with potential biosolids exposure have experienced an increased incidence of microbial-exposure-related illness. The health effects seen in the workers have been attributed to bacterial, viral, and protozoan infections. To the extent that bacteria are the pathogen of concern, it is not clear whether these bacteria are resistant to antibiotics commonly found in biosolids. It is also unclear whether the presence of antibiotics or antibiotic-resistant bacteria increases the susceptibility of these workers. Additional studies will provide more definitive estimates of inhalation and dermal exposures to CIP and AZ and could verify the exposure estimates in this study based on the literature and common exposure factors.

Isolation and characterization of pathogenic Klebsiella pneumoniae strains from lettuce: a potential source of antibiotic resistance and development of a mathematical model for ANOVA results.

This study aimed to evaluate the prevalence of Klebsiella pneumoniae contamination in raw lettuce from Risalpur, Pakistan, and to analyze the antibiotic susceptibility profiles of the isolated strains. The presence of foodborne pathogens such as K. pneumoniae poses significant public health risks, particularly in regions with suboptimal hygiene practices and improper food handling. Lettuce samples were collected from various sources in Risalpur and screened for K. pneumoniae. Antimicrobial susceptibility testing was performed to evaluate the effectiveness of various antibiotics against the isolated strains. Statistical analyses, including ANOVA and linear regression, were conducted to assess differences in inhibition zones and to predict antibiotic effectiveness based on concentration. The results revealed a significant prevalence of K. pneumoniae in the lettuce samples, highlighting the risks associated with poor hygiene, transportation, storage, and contaminated irrigation water. The isolated strains exhibited high susceptibility to gentamicin but demonstrated notable resistance to doxycycline, vancomycin, and ticarcillin. Multidrug-resistant (MDR) strains were identified. ANOVA showed significant differences in inhibition zones, and the linear regression model predicted a Zone of Inhibition based on antibiotic concentration (β0 = 10.6667, β1 = 0.4556). The identification of MDR strains of K. pneumoniae underscores the urgent need for enhanced antibiotic stewardship and food safety protocols to manage foodborne pathogens. Improved hygiene practices throughout the food production and supply chain are critical to mitigate health risks and address the challenge of growing antibiotic resistance.

The Contribution of Dairy Bedding and Silage to the Dissemination of Genes Coding for Antimicrobial Resistance: A Narrative Review.

Antimicrobial resistance (AMR) is a concern in the dairy industry. Recent studies have indicated that bedding serves as a reservoir for antimicrobial-resistant bacteria and antimicrobial-resistance genes (ARGs), while silage has been proposed as another possible source. The impact of AMR in dairy farming can be significant, resulting in decreased productivity and economic losses for farmers. Several studies have highlighted the safety implications of AMR bacteria and genes in bedding and silage, emphasizing the need for further research on how housing, bedding, and silage management affect AMR in farm environments. Exposure to sub-lethal concentrations of antibiotics, such as those from contaminated bedding and silage, can prompt bacteria to develop resistance mechanisms. Thus, even if antimicrobial usage is diminished, ARGs may be maintained in the dairy farm environment. By implementing proactive measures to tackle AMR in dairy farming, we can take steps to preserve the health and productivity of dairy cattle while also protecting public health. This involves addressing the prudent use of antibiotics during production and promoting animal welfare, hygiene, and management practices in bedding and farm environments to minimize the risk of AMR development and spread. This narrative review compiles the growing research, positioning the contribution of bedding and silage to the prevalence and dissemination of AMR, which can elicit insights for researchers and policymakers.

In Vitro Synergistic Activity of Rifampicin Combined with Minimal Effective Antibiotic Concentration (MEAC) of Polymyxin B Against Extensively Drug-Resistant, Carbapenem-, and Polymyxin B-Resistant Klebsiella pneumoniae Clinical Isolates.

We investigated the in vitro antibacterial activity of the combination rifampicin (RIF) + polymyxin B (PB) against extensively drug-resistant (XDR) Klebsiella pneumoniae isolates. We evaluated clinical isolates co-resistant to PB (non-mcr carriers; eptB, mgrB, pmr operon, and ramA mutations) and to carbapenems (KPC, CTX-M, and SHV producers; including KPC + NDM co-producer), belonging to sequence types (ST) ST16, ST11, ST258, ST340, and ST437. We used the standard broth microdilution method to determine RIF and PB minimum inhibitory concentration (MIC) and the checkerboard assay to evaluate the fractional inhibitory concentration index (FICI) of RIF + PB as well as to investigate the lowest concentrations of RIF and PB that combined (RIF + PB) had antibacterial activity. Time-kill assays were performed to evaluate the synergistic effect of the combination against selected isolates. PB MIC (32-256µg/mL) and RIF MIC (32-1024µg/mL) were determined. FICI (<0.5) indicated a synergistic effect for all isolates evaluated for the combination RIF + PB. Our results showed that low concentrations of PB (PB minimal effective antibiotic concentration [MEAC], ≤0.25-1µg/mL) favor RIF (≤0.03-0.125µg/mL) to reach the bacterial target and exert antibacterial activity against PB-resistant isolates, and the synergistic effect was also observed in time-kill results. The combination of RIF + PB showed in vitro antibacterial activity against XDR, carbapenem-, and PB-resistant K. pneumoniae and could be further studied as a potential combination therapy, with cost-effectiveness and promising efficacy.

Occurrence, distribution, and ecological risks of antibiotics and antibiotic resistance genes in the surface waters of Gaoyou Lake, China.

This work examined the occurrence characteristics and ecological risks of 31 antibiotics across five classes and seven ARGs in the surface waters of Gaoyou Lake. A total of 27 antibiotics, spanning four classes, were detected in the surface waters of Gaoyou Lake, with an overall concentration ranging from 57.5 to 114ng/L and an average of 78.8ng/L. Sulfonamide antibiotics exhibited the highest average concentration at 32.7ng/L. Spatial analysis revealed that antibiotic concentration levels in the western region of the lake were higher than those in other areas. Similarly, ARGs were most abundant in this area, with sulfonamide ARGs demonstrating a notably higher mean abundance than other ARGs. Correlation analysis revealed strong positive associations between sul1 and several antibiotics, including sulfadimidine, sulfamethoxazole, ciprofloxacin, lincomycin, clindamycin, erythromycin, and intl1 (P < 0.05), with intra-group correlations among sulfonamide ARGs exceeding those between different ARG groups. Ecological risk assessment indicated that erythromycin and sulfamethoxazole presented medium risks, whereas roxithromycin, azithromycin, and lincomycin were associated with low risks to aquatic organisms. The ecological risk proportions across monitoring sites were primarily low (10.6%) and moderate (16.7%), with no high-risk areas identified and 72.7% presenting no risk. The cumulative ecological risk quotient (RQcum) suggested a medium-risk level at all surveyed sites.

Critical stages in pea photosynthesis impaired by tetracycline as an environmental contaminant.

The widespread use of antibiotics in intensive animal husbandry, and the agricultural utilization of manure from such farms, imposes a significant burden on the environment. Consequently, the effects of antibiotics should be studied not only in animals and humans but also in all components of biocenoses and agrocenoses. In our study, we analyze the impact of four different concentrations of tetracycline present in soil (0, 5, 50, and 500mg/kg of soil) on the growth and key photosynthesis parameters of pea seedlings: chlorophyll concentration, aminolevulinic acid concentration, aminolevulinic acid dehydrogenase activity, and ribulose bisphosphate carboxylase-oxygenase (RuBisCO) activity. At the lowest tetracycline concentration, chlorophyll content decreased by 13% compared to the control (0 tetracycline), while at the highest antibiotic concentration, it decreased by as much as 27%. Similarly, the decrease in aminolevulinic acid (a chlorophyll precursor) concentration was significant, amounting to 34%. However, the activity of the dehydrogenase enzyme, which consumes this precursor, decreased even more drastically by 51%, indicating significant disturbances in the light phase of photosynthesis. However, the activity of RuBisCO in pea plants subjected to tetracycline was even more severely affected, dropping by 58%, 69%, and 70% in soils with increasing concentrations of tetracycline. The reduction in enzyme activity could only partially be explained by a less pronounced decrease in the quantity of RuBisCO (large subunit) protein, which amounted to 6.5%, 11%, and 35% for tetracycline concentrations of 5, 50, and 500mg/kg of soil, respectively.

Assessment of Veterinary Antibiotic Use and Occurrence of Veterinary Antibiotics in Livestock Manure from Farms in Rongai Sub-County, Kenya

Veterinary antibiotics are commonly used in livestock rearing to prevent diseases and stimulate growth. The release of antibiotics into the environment has become a significant environmental and public health concern. This research evaluated antibiotic use, livestock treatment, manure utilization, livestock waste treatment methods and antibiotic residues in livestock manure. Questionnaires were administered to 170 farmers rearing both cattle and poultry. Subsequently, 28 livestock manure samples from 15 cattle and 13 poultry rearing farms were collected from various farms to assess concentrations of tetracyclines (Tetracycline, Oxytetracycline) and sulfonamides (Sulfadiazine, Sulfamethoxazole) residues. Residues analysis was done using High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD). Veterinarians were the most preferred in treating both cattle and poultry in farms. Tetracyclines and sulfonamides were the most consumed class of antibiotics among both poultry and cattle rearing farmers. Compost manure and Biogas were the most preferred use of animal waste within farms. Antibiotic presence in samples was detected in 80% and 93% of cattle and poultry manure respectively. Maximum antibiotic concentrations of 16.24 and 15.18 (mg/kg) were recorded in poultry and cattle manure, respectively. There was a statistically significant difference in antibiotic concentrations in poultry and cattle manure (P&lt;0.05). The results of this research are important in monitoring rising concerns about veterinary antibiotics on environmental and public health.

Multidrug-resistant high-risk clonal Escherichia coli lineages occur along an antibiotic residue gradient in the Baltic Sea

The global spread of multidrug-resistant Escherichia coli threatens human, animal, and environmental health. Despite the recognition of water bodies as potential reservoirs, research on antimicrobial resistance (AMR) and antibiotic residues in the Baltic Sea is limited. In this study, we examined the presence of ESBL-producing E. coli in surface water in northeastern Germany. We then conducted phenotypic and genotypic analyses of the strains, which encompassed AMR and heavy metal/metalloid tolerance, biofilm formation, and detailed plasmid examination. In addition, we used solid-phase extraction with ultra-high performance liquid chromatography and mass spectrometry to quantify antibiotic residues. Our analysis identified 30 ESBL-producing E. coli isolates, some of which were associated with clinically relevant high-risk clonal lineages. We detected antibiotic residues in the environmental samples, but the antibiotic concentrations were significantly lower compared to wastewater samples. These results suggest that the Baltic Sea surface water could serve as a reservoir for ESBL-producing E. coli and clinically relevant antibiotics.

Safety and effectiveness of intraosseous regional prophylactic antibiotics in total knee arthroplasty: a systematic review and meta-analysis.

Intraosseous regional administration (IORA) as a widely applicable and clinically valuable route of administration has gained significant attention in the context of total knee arthroplasty (TKA) for the prophylactic administration of antibiotics. However, there is still controversy regarding its effectiveness and safety. The latest meta-analysis reports that the use of IORA for antibiotics in TKA is as safe and effective as IV administration in preventing prosthetic joint infection (PJI), but they did not separate the statistics for primary TKA and revision TKA, which may be inappropriate. There is currently a lack of evidence specifically comparing the outcomes of prophylactic antibiotic administration via IORA or IV route in primary/revision TKA, respectively, and new research evidence has emerged. In this study, we conducted a systematic review and meta-analysis with the primary objective of comparing the local drug tissue concentration and the incidence of PJI between preoperative IORA and intravenous (IV) administration of prophylactic antibiotics in TKA. Additionally, the occurrence of complications between the two administration routes was also compared. This meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement (PRISMA) guidelines. Retrospective cohort studies and prospective randomized controlled trials that utilized intraosseous local drug delivery for prophylactic antibiotics in knee arthroplasty were included. English literature from PubMed, Embase, and Cochrane Library databases was searched from the inception of each database until December 2023. Two researchers independently screened the literature, assessed the quality, and extracted data according to the inclusion criteria. The primary outcomes were local antibiotic tissue concentration and postoperative PJI incidence, while the secondary outcome was the occurrence of postoperative complications. Statistical analysis was performed using Review Manager 5.3 software. This study included 7 prospective randomized controlled trials and 5 retrospective cohort studies. A total of 4091 patients participated in the 12 included studies, with 1,801 cases receiving IORA and 2,290 cases in the control group. In terms of local drug tissue concentration, intraosseous infusion (IO) 500mg vancomycin significantly increased the drug concentration in the periarticular adipose tissue (SMD: 1.36; 95% CI: 0.87-1.84; P < 0.001; I2 = 0%) and bone tissue (SMD: 0.94; 95% CI: 0.49-1.40; P < 0.001; I2 = 0%) compared to IV 1g vancomycin. Regarding the incidence of postoperative PJI after primary TKA, IO 500mg vancomycin was more effective in reducing the occurrence of PJI compared to IV 1g vancomycin (OR: 0.19; 95% CI: 0.06-0.59; P < 0.001; I2 = 36%). Finally, no significant differences were found between the two groups in terms of postoperative pulmonary embolism (PE) (OR: 1.72; 95% CI: 0.22-13.69; P = 0.59; I2 = 0%) and vancomycin-related complications (OR: 0.54; 95% CI: 0.25-1.19; P = 0.44; I2 = 0%). Preoperative prophylactic antibiotic administration via IORA in TKA significantly increases local drug tissue concentration without significantly increasing systemic drug-related complications compared to traditional IV administration. In primary TKA, low-dose vancomycin via IORA is more effective in reducing the incidence of PJI compared to traditional IV regimens. However, its effectiveness remains controversial in high-risk populations for PJI, such as obese, diabetic, and renal insufficiency patients, as well as in revision TKA.

Polymeric Antibiotic Beads for Canine Osteomyelitis: Advancing Localized Antibiotic Treatment with Enhanced Efficacy and Minimized Side Effects

Antibiotic beads represent a compelling treatment method for the treatment and prevention of canine osteomyelitis, as they provide localized antibiotic concentrations at the infection site with minimal systemic toxicity. The therapeutic efficacy of these beads has been demonstrated, highlighting their potential as a valuable local antibiotic therapy. In particular, the introduction of vancomycin - polymethylmethacrylate (PMMA) beads is highlighted as a promising new form of local antibiotic therapy. This article focuses on the use of antibiotic-impregnated beads to treat localized bacterial infections in the bones and joints of canines. Typically composed of poly(lactic-co-glycolic acid) (PLGA) or polymethylmethacrylate (PMMA), these beads contain antibiotics such as vancomycin, placed directly into the affected area, providing a high antibiotic concentration at the site of infection. These beads were developed for a slow antibiotic release over time; they ensure a constant protective effect against a broad spectrum of bacteria, demonstrating high efficacy and biocompatibility with the animal's body. This localized antibiotic treatment option offers several advantages over systemic antibiotics, such as reduced side effects and improved efficacy. It could be a promising option for the treatment of bone and joint infections in canines.

Opposite Effects of Planting on Antibiotic Resistomes in Rhizosphere Soil with Different Sulfamethoxazole Levels.

Achieving consensus about the rhizosphere effect on soil antibiotic resistomes is challenging due to the variability in antibiotic concentrations, sources, and the elusory underlying mechanisms. Here, we characterized the antibiotic resistomes in both the rhizosphere and bulk soils of soybean plants grown in environments with varying levels of antibiotic contamination, using sulfamethoxazole (SMX) as a model compound. We also investigated the factors influencing resistome profiles. Soybean cultivation altered the structure of antibiotic-resistant genes (ARGs) and increased their absolute abundance. However, the rhizosphere effect on the relative abundance of ARGs was dependent on SMX concentrations. At low SMX levels, the rhizosphere effect was characterized by the inhibition of antibiotic-resistant bacteria (ARBs) and the promotion of sensitive bacteria. In contrast, at high SMX levels, the rhizosphere promoted the growth of ARBs and facilitated horizontal gene transfer of ARGs. This novel mechanism provides new insights into accurately assessing the rhizosphere effect on soil antibiotic resistomes.