Concentrations Of Ampicillin Research Articles

Diverse genomic and epidemiological landscapes of redundant pbp5 genes in Enterococcus spp.: Insights into plasmid mobilization, ampicillin susceptibility, and environmental interactions.

Genetic redundancy in bacteria plays a crucial role in enhancing adaptability and accelerating evolution in response to selective pressures, particularly those associated with rapid environmental changes. Aminopenicillins like ampicillin are important therapeutic options for Enterococcus infections in both humans and animals, with resistance mostly associated with pbp5 gene mutations or overexpression. While the occurrence of redundant pbp5 genes has been occasionally reported, the advantages for the host bacteria have not been explored in detail. During a whole-genome sequencing project of Enterococcus faecium from bacteremic patients, we identified an ST592 strain (Efm57) with redundant pbp5 genes. This presented an opportunity to investigate the prevalence and implications of multiple pbp5 acquisitions in diverse Enterococcus species across various sources, geographical regions, and timeframes. The analysis of 618 complete Enterococcus genomes from public databases revealed that 3.2% harbored redundant pbp5 genes, located on chromosomes or plasmids across different species from diverse epidemiological backgrounds. The proteins encoded by these genes showed homologies ranging from 51.1% to 97.5% compared to native copies. Phylogenetic analysis grouped redundant PBP5 amino acid sequences into three distinct clades, with insertion sequences (mostly IS6-like) facilitating their recent spread to diverse plasmids with varying genetic backbones. The presence of multiple antibiotic resistance genes on pbp5-plasmids, including those conferring resistance to linezolid, underscores their involvement in co-selection and recombination events with other clinically-relevant antibiotics. Conjugation experiments confirmed the transferability of a specific 24kb pbp5-plasmid from the Efm57 strain. This plasmid was associated with higher minimum inhibitory concentrations of ampicillin and conferred bacteria growth advantages at 22°C. In conclusion, the widespread distribution of redundant pbp5 genes among Enterococcus spp. highlights the complex interplay between genetic mobility, environmental factors, and multidrug resistance in overlapping ecosystems emphasizing the importance of understanding these dynamics to mitigate antibiotic resistance spread within the One Health framework.

Antibiotic Residues in Milk and Milk-Based Products Served in Kuwait Hospitals: Multi-Hazard Risk Assessment.

Antimicrobial resistance (AMR) poses a significant global health challenge affecting food safety and development. Residues of antibiotics in food from animal sources, particularly milk, contribute to the development and spread of AMR, alter intestinal microbiota, and potentially lead to allergies, serious health conditions, and environmental and technological problems within the dairy industry. Therefore, this study investigated the residue levels of veterinary drugs from β-lactam antibiotics and tetracyclines in milk and milk products and assessed human health risks. Two hundred milk and milk product samples (pasteurized milk, sterile milk, soft white cheese, and processed cheese, 50 each) were collected from different hospitals in the State of Kuwait and screened for antibiotic residues using a microbial inhibition assay (Delvotest SP-NT) and high-performance liquid chromatography (HPLC). Delvotest SP-NT and HPLC analyses showed that 30, 28, 26, and 24% of the pasteurized milk, sterilized milk, white soft cheese, and processed cheese samples tested positive for antibiotic residues. Forty-eight milk and cheese samples were confirmed as positive by both methods, and six samples initially found to be negative by Delvotest SP-NT were confirmed as positive by HPLC. Multi-antibiotic residues were detected in five samples by using HPLC. The kappa coefficient (0.921; p < 0.0001) revealed complete concordance between the HPLC and Delvotest SP-NT results. Ampicillin was the most abundant residue in the positive samples (31.48%), ranging from 2.44 to 3.89 μg/L, with an overall mean concentration of 3.492 ± 0.094 μg/L, followed by tetracycline and oxytetracycline (27.78% each), ranging from 54.13 to 220.3 μg/L and from 41.55 to 160.7 μg/L, with mean concentrations of 129.477 ± 14.22 and 91.86 ± 9.92 μg/L, respectively. The amoxicillin levels in the samples (12/54; 22.22%) ranged from 3.11 to 5.5 μg/L, with an overall mean concentration of 3.685 ± 0.186 μg/L. The maximum concentrations of ampicillin, amoxicillin, and tetracycline were detected in processed cheese with mean concentrations of 3.89 ± 0.28 µg/L, 3.95 ± 0.15 µg/L, and 170.3 ± 0.27 µg/L, respectively. Pasteurized milk contained the maximum concentrations of oxytetracycline, with a mean concentration of 120.45 ± 0.25 µg/L. The tetracycline residues exceeded the standard maximum residue limits (MRLs; 100 µg/L) in 6% of both pasteurized and sterilized milk samples, and in 4% of processed cheese. Additionally, the oxytetracycline levels in pasteurized milk (6%) and amoxicillin levels in processed cheese (2%) were higher than the permitted MRLs (100 µg/L and 4 µg/L, respectively). Furthermore, the antibiotic residues detected in 12.5% (25/200) of the samples were close to standard permissible MRL limits for ampicillin (5%), amoxicillin and oxytetracycline (3% each), and tetracycline (1.5%). Hazard quotients, which compare the standard acceptable daily intake (ADI) to the estimated daily exposure (EDI), indicated that the overall risk associated with antibiotic residues in these dairy products is low. The EDI was lower than the ADI for the tested antibiotics, indicating an elevated safety margin. While the overall hazard quotients are low, the potential for the development of antibiotic resistance due to long-term exposure to low levels of antibiotics should be considered. Hence, strict regulations and enforcement are necessary to prevent excessive residue levels and to promote responsible antibiotic use in dairy production. Regular monitoring of antibiotic residues in dairy products is essential for ensuring consumer safety.

Laser Speckle Image analysis for identifying the minimum lethal concentration of ampicillin in Escherichia coli liquid cultures

Understanding a pathogen's sensitivity to antimicrobial drugs through Minimum Lethal Concentration (MLC) is crucial for effective treatment planning for bactericidal drugs. In this paper, we propose a novel approach using Laser Speckle Imaging (LSI) to determine the MLC of Escherichia coli (E. coli), a common pathogenic bacterial species. LSI enables the capture and analysis of the dynamic changes in speckle patterns caused by alterations in optical scattering and shape alterations of bacterial cells as a response to antibiotic treatments through a label-free approach. The observed speckle pattern changes are correlated with the gold standard method to determine the MLC, representing the lowest concentration at which E. coli is lethally affected. The results demonstrate the potential of LSI as a reliable and rapid method for determining the MLC of E. coli. This method has much potential for antimicrobial research since it provides a quick, non-destructive evaluation of bacterial responses to various bactericidal antibiotic doses without requiring labor-intensive processes like pour plate tests to calculate the MLC.

A retrospective cohort analysis of factors influencing continuous antibiotic therapy with ampicillin

AimsThere are limited data on ampicillin/sulbactam, both for continuous infusion and for use in critically ill patients. We aimed to identify factors that help predict ampicillin plasma levels during continuous antibiotic therapy in intensive care patients. Main methodsWe retrospectively reviewed and retrieved a large dataset of patients who received continuous ampicillin infusion with therapeutic drug monitoring between 2015 and 2022. Patients initially received standard dosing (single shot of 2/1 g followed by continuous infusion of 6/3 g ampicillin/sulbactam per day), which was then adjusted based on the results of regular therapeutic drug monitoring and according to a target range of 30–60 mg/l (equivalent to four to eight times the minimum inhibitory concentration of ampicillin for Enterobacterales). Main results466 measurements from 225 patients (152 male, mean age 61 years) were analyzed. Initial measurements of ampicillin plasma levels were below the predefined optimal therapeutic range in 50 %, within the range in 30 % and above the range in 20 %. Target attainment increased to 70 % by the 4th measurement. There was a significant negative correlation between ampicillin plasma levels and estimated glomerular filtration rate (eGFR) (r = −0.74; p < 0.001) and, to a lesser extent, with height (r = −0.31; p < 0.001). Based on multiple linear regression, eGFR and body weight or height were the factors accounting for 63 % of the variability in the data. SignificanceTo optimise target achievement, ampicillin dosing in critically ill patients requires a personalized approach based on renal function. Importantly, patients with normal or augmented eGFR require higher standard doses of ampicillin/sulbactam.

Photocatalytic degradation of ampicillin antibiotics in aqueous solution utilizing ZnFe2O4/MWCNTs/TiO2 ternary nanocomposite under solar light irradiation

In this study, a novel photocatalyst composed of zinc ferrite (ZnFe₂O₄), titanium dioxide (TiO₂), and multi-walled carbon nanotubes (MWCNTs) was successfully synthesized via the hydrothermal method, and evaluated for the degradation of ampicillin (AMP) in aqueous solutions. The synthesized nanocomposites were thoroughly characterized using various analytical techniques, including XRD, HR-SEM, HR-TEM, EDX, UV-Vis, FT-IR, BET, and XPS analysis. Crystallite sizes of 24.18 nm for ZnFe₂O₄ and 17.8 nm for TiO₂ were determined. The composite exhibited a band gap of 1.4 eV, indicating its enhanced photocatalytic activity. The photocatalytic performance was assessed under varying conditions, including different nanocomposite dosages (0.3–1 g/L), AMP concentrations (10–50 mg/L), and pH values (2–12). The optimal AMP degradation efficiency of 99.2 % was achieved using 0.7 g/L of the photocatalyst, 10 mg/L of AMP, and a pH of 12 under 90 min of solar irradiation. These optimal parameters were then applied to evaluate AMP degradation using ZnFe2O4, TiO2, and ZnFe2O4/MWCNTs individually, with the degradation rate analyzed using a pseudo-first-order model. The superior photocatalytic efficiency can be primarily attributed to improved charge transfer dynamics and effective electron-hole separation, enabled by the doping of MWCNTs. Hydroxyl radicals (OH•) were identified as the primary reactive species responsible for AMP degradation. Furthermore, the catalyst retained 91 % of its photocatalytic efficiency after eight consecutive cycles, demonstrating excellent stability and reusability. These results underscore the potential of the ZnFe₂O₄/MWCNTs/TiO₂ composite as a highly effective and sustainable photocatalyst for removing pharmaceutical pollutants from aquatic environments.

Phenotypic changes and gene expression profiles of Vibrio parahaemolyticus in response to low concentrations of ampicillin.

Vibrio parahaemolyticus is a leading cause of seafood-associated gastroenteritis and possesses intrinsic resistance to ampicillin. While ampicillin can trigger transcriptional responses of global genes, the behavioral and molecular changes that occur in V. parahaemolyticus when exposed to ampicillin are not fully understood. In this work, we investigated the effects of low concentrations of ampicillin on the physiology and gene expression of V. parahaemolyticus by combining phenotypic assays and RNA sequencing (RNA-seq) analysis. Our results showed that the growth of V. parahaemolyticus were notably delayed, and both motility and c-di-GMP production were significantly inhibited in the response to low concentrations of ampicillin stress. In contrast, biofilm formation by V. parahaemolyticus was enhanced by exposure to low concentrations of ampicillin. However, low concentrations of ampicillin had no effect on the cytotoxicity or adherence activity of V. parahaemolyticus. The RNA-seq data revealed that a low concentration of ampicillin significantly affected the expression levels of 676 genes, including those involved in antibiotic resistance, virulence, biofilm formation, and regulation. This work contributes to our understanding of how V. parahaemolyticus alters its behavior and gene expression in response to ampicillin exposure.

Enhancing the antibacterial activity of ampicillin loaded into chitosan/starch nanocomposites against AMR Staphylococcusaureus

Ampicillin (Amp), an antibiotic, is widely used to treat bacterial infections in humans and livestock, but recently the rate of resistance has increased rapidly. The aim of this work was to enhancing the antibacterial effect of this compound against AMR Staphylococcus aureus via loading Amp into chitosan/starch nanocomposites by spray drying technique. The results showed that the different ratio of chitosan gel and starch gel used in preparing the nanocomposites can affect its properties and performance. The size distribution of the nanocomposite particles was ranging from 122.0 to 816.9 nm. The zeta potential values of the nanocomposites range from +29.47 to +93.07 mV, indicating the stability of the particles and their tendency to repel each other. Ampicillin was loaded into the chitosan/starch nanocomposites with encapsulation efficiency of 70.7–77.3 %, then their releasing and antibacterial effect against AMR S. aureus were investigated. The results indicated that antibacterial activity of chitosan/starch nanocomposites loaded ampicillin was much higher than ampicillin alone. Chitosan/starch nanocomposites loaded ampicillin at concentration 5.0 μg/mL inhibited 88.6 % growth of S. aureus to a similar extent as 7.5 μg/mL of ampicillin alone. Additionally, at same 7.5 μg/mL ampicillin concentration, the nanocomposites loaded ampicillin showed a higher inhibitory rate (93.27 %) compared to ampicillin alone (88.96 %) over a 12 h-period. Especially, the antibacterial activity of chitosan/starch nanocomposites loaded ampicillin still maintained their effectiveness over 48 h (95.43 %) while those the ampicillin decreased down to 85.76 %. This research highlights the potential of using the chitosan/starch nanocomposites as nanocarriers for ampicillin to enhance its antibacterial activity against AMR Staphylococcus aureus. This approach could be a promising strategy to combat antimicrobial resistance.

Effect of subinhibitory concentrations on the spreading of the ampicillin resistance gene blaCMY-2 in an activated sludge microcosm

ABSTRACT As the problem of multi-resistant bacteria grows a better understanding of the spread of antibiotic resistance genes is of utmost importance for society. Wastewater treatment plants contain subinhibitory concentrations of antibiotics and are thought to be hotspots for antibiotic resistance gene propagation. Here we evaluate the influence of sub-minimum inhibitory concentrations of antibiotics on the spread of resistance genes within the bacterial community in activated sludge laboratory-scale sequencing batch reactors. The mixed communities were fed two different ampicillin concentrations (500 and 5000 µg/L) and the reactors were run and monitored for 30 days. During the experiment the β-lactamase resistance gene bla CMY-2 was monitored via qPCR and DNA samples were taken to monitor the effect of ampicillin on the microbial community. The relative copy number of bla CMY-2 in the reactor fed with the sub-minimum inhibitory concentration of 500 µg/L ampicillin was spread out over a wider range of values than the control and 5000 µg/L ampicillin reactors indicating more variability of gene number in the 500 µg/L reactor. This result emphasises the problem of sub-minimum inhibitory concentrations of antibiotics in wastewater. High-throughput sequencing showed that continuous exposure to ampicillin caused a shift from a Bacteroidetes to Proteobacteria in the bacterial community. The combined use of qPCR and high-throughput sequencing showed that ampicillin stimulates the spread of resistance genes and leads to the propagation of microbial populations which are resistant to it.

Effects of Organic Soil Amendments on Antimicrobial-Resistant Bacteria in Urban Agriculture Environments

Biological soil amendments of animal origin (BSAAOs) are widely used in urban agriculture to improve soil quality. Although BSAAO use is regulated due to risks for introducing foodborne pathogens, effects on antimicrobial-resistant (AMR) bacteria are not well established. Here, we aimed to explore the impacts of BSAAOs on levels of resident AMR bacteria in leafy vegetable production environments (i.e., kale, lettuce, chard, cabbage) across urban farms and community gardens in the greater Washington D.C. area (n = 7 sites). Leaf tissue (LT), root zone soil (RZS; amended soil in crop beds), and bulk soil (BS; site perimeter) were collected and analyzed for concentrations of total heterotrophic bacteria (THB), ampicillin (Amp) or tetracycline (Tet) resistant THB, and coliforms. As expected, amended plots harbored significantly higher concentrations of THB than bulk soil (P < 0.001). The increases in total bacteria associated with reduced fractions of Tet-resistant bacteria (P = 0.008), as well as case-specific trends for reduced fractions of Amp-resistant bacteria and coliforms. Site-to-site variation in concentrations of AMR bacteria in soil and vegetable samples reflected differences in land history and crop management, while within-site variation was associated with specific amendment sources, as well as vegetable type and cultivar. Representative isolates of the AMR bacteria and coliforms were further screened for multidrug resistance (MDR) phenotypes, and a high frequency was observed for the former. In amended soils, as the soil pH (range 6.56–7.80) positively correlated with the fraction of Tet-resistant bacteria (rho = 0.529; P < 0.001), crop management strategies targeting pH may have applications to control related risks. Overall, our findings demonstrate that soil amendments promote soil bacteria concentrations and have important implications for limiting the spread of AMR bacteria, at least in the urban landscape.

A quantitative method for the analysis of total and unbound concentrations of amoxicillin, ampicillin, ceftazidime, ceftriaxone, ertapenem, fosfomycin and penicillin G in human plasma with liquid chromatography-tandem mass spectrometry assay.

Monitoring antibiotic plasma levels is critical in populations with altered pharmacokinetics, such as critically ill patients in neonatal or adult intensive care units. This study aimed to develop and validate a rapid, reproducible and sensitive liquid chromatography-tandem mass spectrometry assay (LC-MS/MS) for measuring total and unbound concentrations of amoxicillin, ampicillin, ceftazidime, ceftriaxone, ertapenem, fosfomycin and penicillin G in human plasma. The method required 20 and 250 μl sample volumes for measuring total and unbound concentrations, respectively. Sample preparation involved protein precipitation and the addition of an internal standard. Ultrafiltration separated unbound drugs. Method validation covered selectivity, carryover, linearity, accuracy, precision, dilution effects, matrix effects and stability. The LC-MS/MS was performed within a run time of 7.5min. Calibration curves were linear for ceftazidime and ertapenem (ranges 0.1-50 and 0.05-100 mg/l, respectively) and quadratic for other analytes (0.1-50 mg/l, except for ampicillin: 0.1-20 mg/l; R2 > 0.990). Accuracy was within ±15% of the nominal concentration, and precision did not exceed ±15% (relative standard deviation). Samples showed no significant degradation at the tested temperatures and time points. Clinical applicability was demonstrated in a critically ill neonate. This method with minimal sample volume and short analysis time enables the measurement of total and unbound concentrations of selected antibiotics, and is suitable for routine clinical care and studies.

Click chemistry-based fluorescence polarization sensor for sensitive detection of ampicillin

Ampicillin (AMP) is a β-lactam antibiotic that can inhibit bacterial wall synthesis. The overuse and misuse of AMP makes it micropollutant that commonly found in food and various environmental media. In this work, a fluorescence polarization sensor was designed to sensitive detection of trace ampicillin based on click chemistry, using graphene oxide (GO) as a fluorescence polarization (FP) signal enhancement element. First, when ampicillin binds to its aptamer (apt), the adjacent alkyne and azide groups are separated, hindering the click-linking reaction. When Carboxyfluorescein (FAM) fluorophore-labeled probe (C-FAM) is added, its protruding 3-terminal FAM is recognized and cleaved by exonuclease I (EXO I), releasing fluorophores free that could not be adsorbed on GO, resulting in a lo0wer polarization signal. If there is no AMP in the system, aptamer probe is connected to its complementary chain ends by a click reaction. After C-FAM hybridizes with apt, the apt/P duplex is opened and the prominent single-stranded ends adsorb on the GO, leading a significantly enhanced FP signal. According to the relationship between the difference in FP values and the concentrations of AMP, the limit of detection of proposed method is as low as 80 pg/mL. This assay has a wide linear range plus excellent selectivity, and has been applied to detect AMP in milk and river water samples with satisfactory results, which demonstrates that the FP sensor has great potential for practical applications in food safety and environmental protection fields.

Evolution of mutations in the ftsI gene leading to amino acid substitutions in PBP3 in Haemophilus influenzae strains under the selective pressure of ampicillin and cefuroxime

BackgroundAminopenicillins are recommended agents for non-invasive Haemophilus influenzae infections. One of the mechanisms of resistance to β-lactams is the alteration of the transpeptidase region of penicillin binding protein 3 (PBP3) which is caused by mutations in the ftsI gene. It was shown that exposure to beta-lactams has a stimulating effect on increase of prevalence of H. influenzae strains with the non-enzymatic mechanism of resistance. ObjectivesThe aim of our study was to compare the mutational potential of ampicillin and cefuroxime in H. influenzae strains, determination of minimum inhibitory concentration and the evolution of mutations over time, focusing on amino acid substitutions in PBP3. Methods30 days of serial passaging of strains in liquid broth containing increasing concentrations of ampicillin or cefuroxime was followed by whole-genome sequencing. ResultsOn average, cefuroxime increased the minimum inhibitory concentration more than ampicillin. The minimum inhibitory concentration was increased by a maximum of 32 fold. Substitutions in the PBP3 started to appear after 15 days of passaging. In PBP3, cefuroxime caused different substitutions than ampicillin. ConclusionsOur experiment observed differences in mutation selection by ampicillin and cefuroxime. Selection pressure of antibiotics in vitro generated substitutions that do not occur in clinical strains in the Czech Republic.

Genomic and Transcriptomic Analyses Reveal Multiple Strategies for Vibrio parahaemolyticus to Tolerate Sub-Lethal Concentrations of Three Antibiotics.

Vibrio parahaemolyticus can cause acute gastroenteritis, wound infections, and septicemia in humans. The overuse of antibiotics in aquaculture may lead to a high incidence of the multidrug-resistant (MDR) pathogen. Nevertheless, the genome evolution of V. parahaemolyticus in aquatic animals and the mechanism of its antibiotic tolerance remain to be further deciphered. Here, we investigated the molecular basis of the antibiotic tolerance of V. parahaemolyticus isolates (n = 3) originated from shellfish and crustaceans using comparative genomic and transcriptomic analyses. The genome sequences of the V. parahaemolyticus isolates were determined (5.0-5.3 Mb), and they contained 4709-5610 predicted protein-encoding genes, of which 823-1099 genes were of unknown functions. Comparative genomic analyses revealed a number of mobile genetic elements (MGEs, n = 69), antibiotic resistance-related genes (n = 7-9), and heavy metal tolerance-related genes (n = 2-4). The V. parahaemolyticus isolates were resistant to sub-lethal concentrations (sub-LCs) of ampicillin (AMP, 512 μg/mL), kanamycin (KAN, 64 μg/mL), and streptomycin (STR, 16 μg/mL) (p < 0.05). Comparative transcriptomic analyses revealed that there were significantly altered metabolic pathways elicited by the sub-LCs of the antibiotics (p < 0.05), suggesting the existence of multiple strategies for antibiotic tolerance in V. parahaemolyticus. The results of this study enriched the V. parahaemolyticus genome database and should be useful for controlling the MDR pathogen worldwide.

Multicenter comparison of Etest, Vitek2 and BD Phoenix to broth microdilution for beta-lactam susceptibility testing of Streptococcus pneumonia

PurposeTo assess performance of Etest®, Vitek®2 and BD Phoenix™ to determine the susceptibility of Streptococcus pneumoniae strains to penicillin, ampicillin and cefotaxime.MethodsSixty unique S. pneumoniae challenge strains were selected to cover a wide range of penicillin, ampicillin and cefotaxime minimal inhibitory concentrations (MICs). Strains were analyzed in four different Belgian laboratories. Etest® benzylpenicillin (BEN), ampicillin/amoxicillin (AMP) and cefotaxime (CTA) (bioMérieux), Vitek®2 AST-ST03 (bioMérieux) and BD Phoenix™ SMIC/ID-11 testing were each performed in two different labs. Results were compared to Sensititre® broth microdilution (BMD) (Thermo Fisher Scientific) results. MIC results were interpreted using EUCAST non-meningitis breakpoints (v 13.0).ResultsEssential agreement (EA) was ≥ 90% for all methods compared to BMD, except for Etest® BEN on Oxoid plate (58.3%), Etest® AMP (both on Oxoid (65.8%) and BD BBL plate (84.2%)). Categorical agreement (CA) for penicillin was only ≥ 90% for Vitek®2, for other methods CA ranged between 74 and 84%. CA for AMP was for all methods < 90% (range 75.8–88.3%) and CA for CTA was between 87 and 90% for all methods except for Etest on Oxoid plate (79.2%).ConclusionsOur study indicates that Vitek®2 and BD Phoenix™ are reliable for providing accurate pneumococcal susceptibility results for BEN, AMP and CTA. Using Etest BEN or AMP on Oxoid plate carries a risk of underestimating the MIC and should be interpreted with caution, especially when the obtained MIC is 1 or 2 doubling dilutions below the S or R clinical breakpoint.

Population pharmacokinetic meta-analysis of five beta-lactams antibiotics to support dosing regimens in dogs for surgical antimicrobial prophylaxis

The Pharmacokinetic/Pharmacodynamic (PK/PD) relationship of antimicrobial drugs (AMD) for surgical prophylaxis has been poorly studied, hampering evidence-based decision making around AMD dosing and timing. Our objective is to use PK/PD principles to inform (1) the timing of administration and (2) the interval for re-administration of AMD used peri-operatively in dogs. Raw plasma concentrations of cefazolin, cefuroxime, cefalexin, amoxicillin and ampicillin were retrieved from original intravenous studies performed in dogs. E. coli and methicillin-susceptible staphylococci were identified as possible intraoperative contaminants and their epidemiological cut-offs (ECOFF) were retrieved from the EUCAST database. Individual PK data were refitted with non-linear mixed effect models (Phoenix®). We performed Monte Carlo simulation to compute i) the 95th percentile of time of peak concentration in the peripheral compartment (informing timing between administration and first incision) and ii) the duration for which at least 90% of dogs maintain a free plasma concentration above ECOFF (informing timing of re-administration: 1.5–4 h). Cefazolin (22–25 mg/kg), cefuroxime (20 mg/kg), cefalexin (15 mg/kg) and amoxicillin (16.7 mg/kg) reached peak peripheral concentrations within 30 min, but ampicillin (20 mg/kg) required 82 min, respectively. For methicillin-susceptible staphylococci, cefazolin and cefuroxime require re-administration every 2 h, whereas cefalexin and both amoxicillin and ampicillin can be readministered every 3 and 4 h, respectively. For E. coli, only cefazolin provided adequate perioperative coverage with 2-hourly administration, where cefuroxime and cefalexin failed uniformly. Alternatively, ampicillin and amoxicillin (critically ill dogs) may cover E. coli contaminations, but only if readministered every 1.5 h. These PK-derived conclusions provide a rationale for perioperative AMD administration timing.

Biocompatibility Evaluation of Ampicillin-Loaded Whitlockite for Bone Regeneration.

Introduction Whitlockite (WH), a rare phosphate mineral within the apatite group, shows potential for bone regeneration owing to its superior composition and biocompatibility compared to hydroxyapatite. It can serve as a carrier for bioactive molecules, gradually releasing them to stimulate bone growth and expedite healing. This study aims to assess the biocompatibility of antibiotic-loaded WH, focusing on ampicillin, for bone regeneration applications. Methodology WH particles loaded with varying concentrations of ampicillin (10 and 25 mM) underwent biocompatibility assessments using the MTT assay. One gram of particles was incubated in 10 mL of culture medium for 24 and 48 hours. Experimental groups included control, WH, WH with ampicillin at 10 mM (WH+A10), WH with ampicillin at 25 mM (WH+A25), and positive control treated with 0.1% Triton X detergent. Subsequently, after a three-day culture period, RunX2 gene expression, indicative of osteoblastic differentiation, was quantified using real-time PCR analysis. Results Our research evaluated the bioactivity of WH particles treated with human osteoblastic cells using the MTT assay. While 10 mM ampicillin-loaded WH showed no significant difference in metabolic activity at both 24 and 48 hours, 25 mM ampicillin-loaded WH exhibited a slight reduction in metabolic activity at 24 hours, which normalized by 48 hours. Additionally, we assessed osteogenic potential and showed a significant increase in RunX2 expression with ampicillin-loaded WH, indicating sustained osteogenic properties. Conclusions Our study underscores the promising biocompatibility of WH particles by retaining their osteogenic properties even when, loaded with ampicillin, offering a potential avenue for future bone regeneration strategies.

Ampicillin detection using absorbance biosensors utilizing Mn-doped ZnS capped with chitosan micromaterials

The detection of ampicillin plays a crucial role in managing and monitoring its usage and resistance. This study introduces a simple and effective biosensor for ampicillin detection, utilizing the unique absorbance features of Mn-doped ZnS capped by chitosan micromaterials in conjunction with β-lactamase activity. The biosensors can detect ampicillin concentrations from 13.1 to 72.2 μM, with a minimum detection limit of 2.93 μM for sensors based on 300 mg/L of the sensing material. In addition, these sensors show high specificity for ampicillin over other antibiotics such as penicillin, tetracycline, amoxicillin, cephalexin, and a non-antibiotic-glucose. This specificity is demonstrated by an enhancing effect when beta-lactamase is used, as opposed to a quenching effect observed at 340 nm in the absorbance spectrum when no beta-lactamase is present. This research highlights the potential of affordable chitosan-capped Mn-doped ZnS micromaterials for detecting ampicillin through simple absorbance measurements, which could improve the monitoring of antibiotics in both clinical and environmental settings.

Fungal Bioremediation of the β-Lactam Antibiotic Ampicillin under Laccase-Induced Conditions.

Due to widespread overuse, pharmaceutical compounds, such as antibiotics, are becoming increasingly prevalent in greater concentrations in aquatic ecosystems. In this study, we investigated the capacity of the white-rot fungus, Coriolopsis gallica (a high-laccase-producing fungus), to biodegrade ampicillin under different cultivation conditions. The biodegradation of the antibiotic was confirmed using high-performance liquid chromatography, and its antibacterial activity was evaluated using the bacterial growth inhibition agar well diffusion method, with Escherichia coli as an ampicillin-sensitive test strain. C. gallica successfully eliminated ampicillin (50 mg L-1) after 6 days of incubation in a liquid medium. The best results were achieved with a 9-day-old fungal culture, which treated a high concentration (500 mg L-1) of ampicillin within 3 days. This higher antibiotic removal rate was concomitant with the maximum laccase production in the culture supernatant. Meanwhile, four consecutive doses of 500 mg L-1 of ampicillin were removed by the same fungal culture within 24 days. After that, the fungus failed to remove the antibiotic. The measurement of the ligninolytic enzyme activity showed that C. gallica laccase might participate in the bioremediation of ampicillin.

Protective effects of antibiotic resistant bacteria on susceptibles in biofilm: Influential factors, mechanism, and modeling

In environmental biofilms, antibiotic-resistant bacteria facilitate the persistence of susceptible counterparts under antibiotic stresses, contributing to increased community-level resistance. However, there is a lack of quantitative understanding of this protective effect and its influential factors, hindering accurate risk assessment of biofilm resistance in diverse environment. This study isolated an opportunistic Escherichia coli pathogen from soil, and engineered it with plasmids conferring antibiotic resistance. Protective effects of the ampicillin resistant strain (AmpR) on their susceptible counterparts (AmpS) were observed in ampicillin-stress colony biofilms. The concentration of ampicillin delineated protective effects into 3 zones: continuous protection (<1 MIC of AmpS), initial AmpS/R dependent (1–8 MIC of AmpS), and ineffective (>8 MIC of AmpS). Intriguingly, Zone 2 exhibited a surprising “less is more” phenomenon tuned by the initial AmpS/R ratio, where biofilm with an initially lower AmpR (1:50 vs 50:1) harbored 30–90 % more AmpR after 24 h growth under antibiotic stress. Compared to AmpS, AmpR displayed superiority in adhesion, antibiotic degradation, motility, and quorum sensing, allowing them to preferentially colonize biofilm edge and areas with higher ampicillin. An agent-based model incorporating protective effects successfully simulated tempo-spatial dynamics of AmpR and AmpS influenced by antibiotic stress and initial AmpS/R. This study provides a holistic view on the pervasive but poorly understood protective effects in biofilm, enabling development of better risk assessment and precisely targeted control strategies of biofilm resistance in diverse environment.

Correlation between the development of phage resistance and the original antibiotic resistance of host bacteria under the co-exposure of antibiotic and bacteriophage

Bacteriophages (phages) are viruses capable of regulating the proliferation of antibiotic resistant bacteria (ARB). However, phages that directly cause host lethality may quickly select for phage resistant bacteria, and the co-evolutionary trade-offs under varying environmental conditions, including the presence of antibiotics, remains unclear as to their impact on phage and antibiotic resistance. Here, we report the emergence of phage resistance in three distinct E. coli strains with varying resistance to β-lactam antibiotics, treated with different ampicillin (AMP) concentrations. Hosts exhibiting stronger antibiotic resistance demonstrated a higher propensity to develop and maintain stable phage resistance. When exposed to polyvalent phage KNT-1, the growth of AMP-sensitive E. coli K12 was nearly suppressed within 18 h, while the exponential growth of AMP-resistant E. coli TEM and super-resistant E. coli NDM-1 was delayed by 12 h and 8 h, respectively. The mutation frequency and mutated colony count of E. coli NDM-1 were almost unaffected by co-existing AMP, whereas for E. coli TEM and K12, these metrics significantly decreased with increasing AMP concentration from 8 to 50 μg/mL, becoming unquantifiable at 100 μg/mL. Furthermore, the fitness costs of phage resistance mutation and its impact on initial antibiotic resistance in bacteria were further examined, through analyzing AMP susceptibility, biofilm formation and EPS secretion of the isolated phage resistant mutants. The results indicated that acquiring phage resistance could decrease antibiotic resistance, particularly for hosts lacking strong antibiotic resistance. The ability of mutants to form biofilm contributes to antibiotic resistance, but the correlation is not entirely positive, while the secretion of extracellular polymeric substance (EPS), especially the protein content, plays a crucial role in protecting the bacteria from both antibiotic and phage exposure. This study explores phage resistance development in hosts with different antibiotic resistance and helps to understand the limitations and possible solutions of phage-based technologies.