In vitro and in vivo evaluation of antibacterial activity of 1,8-cineol and the essential oil of Myrciaria pilosa Sobral & Couto.

Ampicillin (AMP) is an organic anion drug widely used in clinical setting as a β-lactam antibiotic. However, the specific transporter involved in mediating AMP transport remains unidentified. Thus, we investigated whether organic anion transporters1/3 (OAT1/3) mediate the renal transport of AMP in this study. Both rOAT1/OAT3 (Slc22a6/Slc22a8) double-knockout and wild-type (WT) rats were administered AMP via intraperitoneal injection simultaneously. Following the knockout, a significant increase in AMP plasma concentration and the area under the plasma concentration-time curve (AUC) was observed, accompanied by a marked reduction in cumulative urinary excretion. OAT1/3-overexpressing cell uptake experiments demonstrated that AMP is a substrate of OAT3, with a Michaelis-Menten constant (Km) of 138.6μM and a maximum transport velocity (Vmax) of 80.43pmol/mg protein/min. In conclusion, AMP was identified as a substrate of OAT3, rather than OAT1.

Healing wounds may lead to significant troubles affecting human health. Hence, establishing an affordable method to speed up and improve the healing process is necessary. In this study, we report for the first time the fabrication and in vivo evaluation of sodium ampicillin (AMP)-loaded, citric-acid-cross-linked polyvinyl alcohol/dextran (CA/PVA/Dex)-electrospun nanofibers (NFs) as a multifunctional wound dressing. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) confirmed a successful cross-linking and NF formation. An optimized CA concentration of 5.0wt% produced uniform, bead-free nanofibrous mats with improved structural with structural integrity and sustained AMP release. The wound healing activity of the fabricated NFs was evaluated via in vivo wound healing studies and histopathological examination using a rat excision wound model. AMP-loaded CA/PVA/Dex NFs significantly enhanced wound closure, re-epithelialization, and collagen deposition compared to AMP-free NFs, with a clear dose-dependent improvement. The obtained results demonstrated that controlled local delivery of AMP through optimized CA-cross-linked PVA/Dex NFs markedly accelerates wound healing. Therefore, the developed AMP-loaded CA/PVA/Dex electrospun nanofibrous mats represent a novel, biocompatible, and effective wound dressing platform with strong potential for clinical wound management.

Electromembrane extraction using deep eutectic solvent-supported liquid membranes in a 3D-printed multi-compartment device for multi-class pharmaceutical analysis in wastewater.

Mesoporous silica supported Au-Cu bimetallic nanoparticles-based electrochemical aptasensor for estimation of ampicillin in milk.

The current research work elucidates the identification, synthesis and characterisation of two critical impurities of ampicillin trihydrate, designated as N-formyl ampicilloic acid and D-phenylglycylampicillin (European Pharmacopoeia impurity I). The formation of N-formyl ampicilloic acid results from the cross-contamination of ampicillin trihydrate with residual formic acid, whereas D-phenylglycylampicillin arises through the amidation of amino group in the side chain of ampicillin trihydrate with D-phenylglycine methylester. These impurities substantially affect the overall quality of the ampicillin trihydrate API; therefore, their identification and control are critical. This work holds significant value for the generic pharmaceutical industry, as an efficient synthetic route for these impurities has been established using readily accessible starting materials.

Background/Objectives: Multidrug-resistant (MDR) strains of Streptococcus suis are increasingly prevalent and present significant challenges in clinical management. Given that the development of new antibiotics is a resource-intensive process and time-consuming, there is an urgent need for alternative therapeutic strategies to address resistance in the short term. One promising approach is the use of combination therapy, which involves pairing potent antibiotics with agents that may be less effective on their own, to enhance therapeutic efficacy and potentially overcome resistance mechanisms. This study aimed to investigate the in vitro antibacterial activity of combining two classes of antibiotics with distinct mechanisms of action-cell wall synthesis inhibitors and protein synthesis inhibitors-against MDR S. suis strains isolated from diseased pigs. Methods: A total of 36 MDR S. suis strains were tested using a microbroth dilution checkerboard assay to determine the minimum inhibitory concentration (MIC) of four cell wall synthesis inhibitors -amoxicillin/clavulanic acid (AMC), ampicillin (AMP), penicillin G (PEN), and vancomycin (VAN)- in combination with four protein synthesis inhibitors -gentamicin (GEN), neomycin (NEO), tilmicosin (TMS), and tylosin (TYL). Time-kill curve assays were conducted to evaluate the in vitro bactericidal activity of synergistic antibiotic combinations (PEN-GEN and AMP-NEO) against Beta-lactam-resistant and Beta-lactam-susceptible MDR S. suis strains. Results: Checkerboard analysis revealed that penicillin-gentamicin combination exhibited the most effective synergistic activity against the MDR S. suis strains (10/19, 52.6%), with ∑FIC values of 0.25-1.06 and MIC reductions from resistant to susceptible levels. Time-kill assays further confirmed the synergistic bactericidal effect of the combination, demonstrating complete bacterial clearance within 6-9 h, markedly rapid bacterial killing compared to monotherapy. Conclusions: This study demonstrates that antibiotic combinations, particularly Beta-lactams combined with aminoglycosides, show synergistic activity against pig-isolated S. suis MDR strains. The PEN-GEN combination exhibited strong synergistic and bactericidal effects, supporting combination therapy as a potential strategy to address antimicrobial resistance. Further evaluation in diverse strain backgrounds and prudent antibiotic use are essential to confirm efficacy and limit the emergence of antibiotic resistance.

This study was designed to investigate the basis of atypical ampicillin/sulbactam (SAM) resistance in Salmonella isolates from raw chicken that lacked extended-spectrum or inhibitor-resistant TEM β-lactamase variants. The ampicillin (AMP) minimum inhibitory concentrations (MICs) of all Salmonella isolates and blaTEM expression and copy numbers of select isolates were determined. Plasmids from select Salmonella isolates were conjugated into Escherichia coli recipients, and their AMP MICs, SAM resistance phenotypes, and blaTEM expression were quantified. SAM-resistant Salmonella isolates displayed ∼5.4-fold higher average AMP MIC and significantly elevated blaTEM expression levels compared to SAM-susceptible control. Conjugation experiments revealed differences in AMP MICs and SAM resistance phenotypes between Salmonella donors and E. coli transconjugants. An AMP MIC breakpoint of 1024ppm ostensibly confers resistance to SAM in Salmonella. Host-dependent blaTEM overexpression and resulting β-lactamase hyperproduction can lead to atypical SAM resistance in Salmonella. This study furthers our understanding of the understudied SAM resistance in Salmonella spp.

Salmonella remains a significant zoonotic pathogen, and its antimicrobial resistance in agricultural settings poses a serious public health risk. In this study, we investigated the prevalence, serotype distribution, sequence types, and antimicrobial resistance profiles of Salmonella isolates from a homebred chicken farm in Jiangsu Province, China. Among 229 cloacal swab samples collected from two residential buildings, 60 Salmonella strains were isolated (isolation rate: 26.20%), with no isolates detected in environmental samples (n = 60). Differences in prevalence were observed among chicken breeds within the same building. All isolates belonged to two serotypes: S. Enteritidis (SE, 56.67%) and S. Kentucky (SK, 43.33%). Multilocus sequence typing (MLST) classified the strains into two sequence types: ST11 (n = 34) and ST198 (n = 26), with clear spatial clustering suggesting clonal dissemination within specific breeds. Antimicrobial susceptibility testing revealed high resistance rates to erythromycin (E), amoxicillin (AML), and ampicillin (AMP), exceeding 90%. All isolates were resistant to at least two antimicrobial agents, and one strain exhibited resistance to eight agents. Resistance gene screening showed that all isolates carried mutations in gyrA (S83F, D87G, D87Y) and parC (S80I). Additionally, aph3'-Ib and aph(6)-Id were detected in 68.33% of isolates. All strains harbored two or more antimicrobial resistance genes (ARGs). Whole-genome SNP analysis confirmed strong phylogenetic clustering by serotype and building, with ≤ 5 SNP differences within clades, indicating clonal persistence dissemination events. Homologous strain analysis (SNP distance ≤ 10) further revealed within-farm transmission of closely related strains. These findings highlight the clonal spread of multidrug-resistant Salmonella in chicken farms and underscore the need for improved surveillance and infection control measures in agricultural environments.

Antimicrobial resistance (AMR) in pathogenic bacteria remains a major challenge and critical threat to the global healthcare industry, demanding alternative therapeutic strategies. Among the various nanomaterials studied, silver nanoparticles (Ag-NPs) have shown promising antibacterial properties due to their broad-spectrum activity, oligodynamic effect, and reduced possibility of inducing microbial resistance. This study investigates the antimicrobial efficacy of biogenically synthesised silver nanoparticles using a cell-free extract of Enterobacter xiangfangensis Pb204 combined with antibiotics against eight pathogenic bacterial strains, including ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.), E. coli, and Vibrio cholerae. The biogenic Ag-NPs were characterised by ultraviolet-visible (UV-Vis) spectroscopy and transmission electron microscopy (TEM) with energy-dispersive spectroscopy (EDS) analysis. Disc diffusion assays demonstrated that biogenic Ag-NPs (21 µg and 25 µg) effectively inhibited the growth of all tested pathogens. When Ag-NPs were combined with antibiotics amoxicillin/clavulanic acid (AMC), ampicillin (AMP), ciprofloxacin (CIP), meropenem (MEM), and vancomycin (VAN), most inhibition zones expanded, with the greatest synergistic effect observed in combination with vancomycin against Enterococcus faecium. These results support the potential of combined therapies using antibiotics and biogenic Ag-NPs to combat the effects of AMR in clinically significant pathogens.

Detection of antibiotic-resistant Escherichia coli using surface-enhanced Raman spectroscopy and infrared spectroscopy.

Background/aimThe cross-kingdom biofilm structure formed by Candida tropicalis and Streptococcus mutans may increase caries formation. The aim of this study was to evaluate the in vitro effect of the exogenous tyrosol on single- and dual-species biofilms as well as planktonic cultures formed by C. tropicalis and S. mutans.Materials and methodsThe antimicrobial efficacy of tyrosol was evaluated through broth microdilution, colony-forming unit (CFU) enumeration, and XTT reduction tests to assess cell viability and metabolic activity. Transmission electron microscopy (TEM) was used to examine ultrastructural changes in planktonic cells. Biofilm dynamics were visualized via scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The in vitro cytotoxicity of tyrosol was evaluated using NIH/3T3 fibroblast cells.ResultsXTT results showed that the biofilm-reducing effect of amphotericin B (AMB) on single C. tropicalis biofilm at the minimum inhibitory concentration (MIC) and 2× MIC was significantly higher than that of control (47% and 48%, respectively) (p < 0.05). Tyrosol also had a metabolic activity-reducing effect on single C. tropicalis biofilm, but this effect was not statistically significant (39% at 2× MIC and 42% at MIC). Tyrosol and ampicillin (AMP) had no significant reducing effect on single S. mutans biofilm cells (p > 0.05). However, AMP resistance increased in dual culture. CFU enumeration, TEM, SEM, and CLSM data supported these findings. The effect of tyrosol on NIH/3T3 fibroblast cells was suppressive at low concentrations (1–4 mg/mL) and enhancing at high concentrations (4.5–20 mg/mL).ConclusionThis study investigated the antimicrobial and antibiofilm properties of tyrosol against C. tropicalis and S. mutans, individually and in combination. The results showed that tyrosol inhibited growth and biofilm formation, particularly in dual-species biofilms. Although S. mutans had greater resistance, overall microbial viability was reduced. Despite some observed increase in AMP resistance, tyrosol was selectively cytotoxic, indicating its promise as a natural therapeutic agent pending further research.

SUMMARYEmerging studies suggest that antibiotics can disrupt the gut microbiome and alter vaccine-induced immune responses, but the specific consequences of early-life exposure on neonatal immune development remains poorly understood. Here, we examined how two antibiotics frequently used in perinatal care, broad-spectrum ampicillin (AMP) and the extended-spectrum combination amoxicillin/clavulanate (AMOX/CLAV), administered during gestation and lactation, influence neonatal gut microbiome composition, fecal metabolome profiles, and responses to the 20-valent pneumococcal conjugate vaccine (PCV20). Maternal treatment with AMOX/CLAV, but not AMP, significantly reduced PCV-specific IgG titers at 4- and 6-weeks post-prime immunization compared to untreated controls. Exclusive exposure to AMOX/CLAV also impaired sneutrophil-mediated opsonophagocytic killing, indicating diminished antibody functionality. These effects were transient, with immune parameters normalizing by week 8 post-prime immunization. Metabolomic and microbiome profiling revealed that maternal AMP and AMOX/CLAV differentially perturbed specific metabolite classes including bile acids, N-acyl lipids, and indole-derivatives, as well as key commensal taxa including Bacteroidales and Coriobacteriales within the gut microbiota. Together, these findings reveal a previously underappreciated maternal-offspring route of antibiotic influence that transiently disrupts neonatal vaccine responsiveness through microbiome and metabolome alterations. These results highlight maternal antibiotic exposure as a modifiable factor shaping early-life immunity.

Antibiotics significantly change gut microbiota, leading to dysbiosis and changes in bacterial community composition, which further results in a series of dysfunctions with severe health consequences. This work employed both culture-dependent and -independent methods to examine antibiotic-induced changes in gut microbiota at higher resolution using mouse models. By following bacterial changes and antibiotic resistance daily before antibiotic exposure, after antibiotic exposure, and during recovery, several significant novel findings were made. Ampicillin (AMP) and imipenem (IPM) treatment led to an acute, exponential, but temporary bloom in absolute abundances of live opportunistic pathogens Enterobacteriaceae and Enterococcus, while not affecting potentially beneficial Lactobacillus. The absolute abundances of antibiotic-resistant opportunistic pathogens followed a similar pattern. Impact on antibiotic resistance, on the other hand, is significant and persistent. Nearly, all Enterobacteriaceae performed AMP-resistant at the end of treatment with AMP, and almost 10% of Enterococcus became IPM-resistant following treatment with IPM. Further analysis of the genomes of isolated bacteria suggested that the former was due to replacement of Enterobacteriaceae strains while the latter is not. These studies show that antibiotic exposure led to expansion of gastrointestinal pathogens and their resistance to antibiotics, increasing risks for bacterial infections, contrary to the traditional anti-infection functions of antibiotics.IMPORTANCEThe antibiotic therapy is the primary method for treating and preventing bacterial infections. However, the consumption of antibiotics may also cause collateral damage in the normal microbial flora in human body, leading to dysbiosis with unwanted consequences. This impact was previously studied mostly with sequencing-based methods, which did not distinguish between live and dead cells, and did not provide absolute quantitative data, limiting the physiological relevance of discoveries. This work expands the methods in studying the side effects of antibiotic therapy by including culturing methods that measure absolute quantities of live bacteria. Surprising findings were made that antibiotic uptake can lead to temporary exponential bloom of opportunistic pathogens in mouse gut, and a permanent change of antimicrobial resistance in these pathogens. These findings expand our knowledge on how antibiotic therapy can affect our health and urges caution on casual antibiotic usage.

Raphasemenate A-J: Ten phenylpropionates with antibacterial activity from Raphani Semen.

Ampicillin-induced resistant variants of Listeria monocytogenes: effects on growth, survival, and virulence.

Photodynamic inactivation (PDI) represents a promising strategy to overcome bacterial resistance by combining light, oxygen, and a photosensitizer (PS) to generate reactive oxygen species (ROS) that damage essential cellular components. Combining PDI with conventional antibiotics (ATBs) may further enhance bacterial eradication through complementary mechanisms. In this study, the tetracationic 5,10,15,20-tetra(4-N,N,N-trimethylammoniophenyl)porphyrin (TMAP4+) was evaluated in combination with ATBs: ampicillin (AMP) and rifampicin (RIF) against Staphylococcus aureus and cephalexin (CFX) against Escherichia coli. The photostability of all agents was assessed under the experimental irradiation conditions, and no evidence of physical interaction between TMAP4+ and the ATBs was detected. AMP and CFX remained photostable, while RIF exhibited only minimal photodegradation under white light, confirming its stability during PDI treatments. The antimicrobial assays revealed that irradiation significantly enhanced the bactericidal activity of TMAP4+. When combined with ATBs, photoactivated TMAP4+ led to a pronounced reduction in the minimum inhibitory concentration (MIC) values of AMP and RIF for S. aureus and of CFX for E. coli, indicating additive effects. Growth curve analyses corroborated these results, showing delayed bacterial growth and decreased maximal optical densities in the combined treatments compared to single agents. Overall, these findings demonstrate that the photodynamic process can potentiate the antimicrobial effect of conventional ATBs without compromising their stability, supporting the potential of PS-ATB combination therapies as a valuable approach to improve antibacterial efficacy and mitigate ATB resistance.

Background: Antimicrobial resistance (AMR) is a growing global health concern, posing a serious risk to public health and threatens to compromise the efficacy of antimicrobial treatments. Developing effective ways to address it requires an understanding of its mechanics, drivers, and consequences. Objectives: The present study was designed to identify, characterize, and assess the antibiotic susceptibility profiles of two bacteria isolated from marine water samples obtained from the Atlantic Ocean in Lagos, Nigeria. Methods: The two bacterial isolates from the marine water sample used in this study were obtained from stock cultures maintained on nutrient agar (NA) slants. These slants were sealed to prevent desiccation and stored at 4°C in the microbiology laboratory of the department. Pure, distinct colonies of the isolates were subcultured on NA and eosin methylene blue (EMB) plates and examined for their morphological characteristics. Gram staining and various important biochemical assays were performed, and antibiotic susceptibility was assessed using the Kirby-Bauer disk diffusion method Results: The two bacteria isolates were identified as Pseudomonas aeruginosa and Escherichia coli. Both were resistant to ampicillin (AMP), tetracycline (TET), and nitrofurantoin (NIT) but exhibited distinct morphological and biochemical traits. Conclusions: The presence of multi-drug resistant P. aeruginosa and E. coli. in the studied marine environment suggests that it may serve as a reservoir for AMR genes, highlighting the urgent need for local antimicrobial stewardship.

In this study, a one-step hydrothermal method was employed to synthesise highly fluorescent carbon quantum dots (Mn, N-CDs), incorporating the metallic element manganese (Mn) and the non-metallic element nitrogen (N). Banana peels and potassium permanganate were utilised as the raw materials. Characterisation methods were used to investigate the structure and properties of the Mn, N-CDs, revealing that they exhibited excellent fluorescence performance. The Mn, N-CDs was then applied as a fluorescent probe for penicillin detection, revealing that it significantly affected the fluorescence intensity of the Mn, N-CDs via a static quenching mechanism. Furthermore, the concentration of ampicillin sodium exhibited a strong linear relationship within the range of 0.05–20 µg/mL. Furthermore, antibiotics in environmental wastewater were analysed and spiked recovery experiments were performed. The results showed that ampicillin sodium recovery was 96.0-98.20%, with an RSD of less than 2.41%. In summary, this method provides a novel nanosensing platform for the rapid detection of antibiotic residues, with potential applications in environmental testing.

To report the incidence of intraoperative surgical site positive bacterial cultures and occurrence of postoperative infection following elective castration in rams and to measure, in different units, the concentrations of benzylpenicillin, ampicillin, and oxytetracycline in resected tissues following preoperative SC administration. In January and February 2016, healthy rams were enrolled before elective castration and were randomly assigned to the control group (saline) or subcutaneous treatment groups (22,000 IU/kg of procaine benzylpenicillin, 6.6 mg/kg of ampicillin trihydrate, or 6.6 mg/kg of oxytetracycline dihydrate administered within 2 hours before resection of the tissues). Excised tissues were sampled to measure drug concentrations by reverse phase high-performance liquid chromatography-tandem mass spectrometry. The surgical site was swabbed at the end of the procedure for anaerobic and aerobic cultures. Rams were monitored for 2 weeks after surgery. The tissues' weight-to-volume ratio in 10 additional rams was measured in May 2022 to allow conversion of drug concentration from ng/g to µg/mL. No microbial growth or postoperative complications were detected in 46 rams. The concentration of benzylpenicillin, ampicillin, and oxytetracycline was successfully measured in all tissues and reported in ng/mL and µg/mL. Prophylactic administration of antimicrobials is unlikely indicated for elective castration in rams in a hospital setting. Concentrations of antimicrobials were detected in resected tissues within 2 hours after SC injection. The relevance of the conversion of drug concentration from ng/g to µg/mL needs further investigation. Avoiding prophylactic administration of antimicrobials for elective castration aligns with the principles of antimicrobial stewardship. Without sound rationales, extralabel routes of injection should be discouraged in rams undergoing castration.