In the present work, we synthesized the carbon quantum dots (CQDs) by one step hydrothermal method using the dried beet powder as the carbon source without additional chemical reagents and functionalization. The as-prepared CQDs are quasi-spherical carbon nanoparticles with diameters of 4-8 nm as well as surface functional groups such as carboxyl and hydroxyl groups, and exhibit good water-solubility, biocompatibility, and strong fluorescence. It is confirmed that amoxicillin (AMO) could enhance the fluorescent intensity of CQDs, the I/I 0 showed a linear correlation between the intensity of fluorescence and the concentration of AMO in a broad range. These superior properties render a potential application of the CQDs in biomedical.

A validation study was conducted for an immunochromatographic method (BetaStar® Advanced for Beta-lactams) for the detection of beta-lactam residues in raw, commingled bovine milk. The assay detected amoxicillin, ampicillin, cloxacillin, penicillin, cephapirin, and ceftiofur below the U.S. Food and Drug Administration tolerance levels but above the maximum sensitivity thresholds established by the National Conference on Interstate Milk Shipments. The results of internal and independent laboratory dose-response studies employing spiked samples were in agreement. The test detected all six drugs at the approximate 90/95% sensitivity levels in milk from cows treated with each drug. Selectivity of the assay was 100%, as no false-positive results were obtained in testing 1148 control milk samples. Testing the estimated 90/95% sensitivity level for amoxicillin (8.5 ppb), ampicillin (6.9 ppb), cloxacillin (8.9 ppb), penicillin (4.2 ppb), and cephapirin (17.6 ppb), and at 100 ppb for each antibiotic, resulted in 94-100% positive tests for each of the beta-lactam drugs. The results of ruggedness experiments established the operating parameter tolerances for the assay. Cross-reactivity testing established that the assay detects other certain beta-lactam drugs, but it does not cross-react with any of 30 drugs belonging to seven different drug classes. Abnormally high bacterial or somatic cell counts in raw milk produced no assay interference.

A method was developed for the determination of amoxicillin and metronidazole in human serum. The procedure used was hydrophilic interaction chromatography (HILIC) followed by mass spectrometric (MS) detection. Chromatographic separation was achieved on a ZIC-HILIC column and the mobile phase consisted of a mixture of 0.1% (v/v) formic acid in water and 0.1% (v/v) formic acid in acetonitrile. The method was validated with regard to selectivity, accuracy, precision, calibration, lower limit of quantification (LOQ), extraction recovery and matrix effect. The LOQs were 0.0138 and 0.008 μg/ml for amoxicillin and metronidazole respectively, while for quantification purposes linearity was achieved in the range of 0.1 μg/ml to 6.4 μg/ml for both drugs with correlation coefficients >0.9990. The intraday precision (expressed as %RSD) and the accuracy (expressed as the % deviation from the nominal value) was <15% for both antibiotics at all QC levels. Extraction recoveries for both drugs and internal standards were >80%, while a considerable matrix effect (<60%) was observed for amoxicillin. Finally, the method was applied to the determination of amoxicillin and metronidazole concentrations in serum for 20 patients.

Antibiotics are not efficiently removed in conventional wastewater treatments. In fact, different Advanced Oxidation Process (AOPs), including ozone, peroxide, UV radiation, among others, are being investigated in the elimination of microcontaminants. Most of AOPs proved to be efficient on the degradation of antibiotics, but the mineralization is on the one hand not evaluated or on the other hand not high. At this work, the UV-based hybrid process, namely Photo-assisted electrochemical Oxidation (PEO), was applied aiming the mineralization of microcontaminants such as the antibiotics Amoxicillin (AMX), Norfloxacin (NOR) and Azithromycin (AZI). The influence of the individual contributions of Electrochemical Oxidation (EO) and the UV-base processes on the hybrid process (PEO) were analyzed. Results showed that AMX and NOR presented higher mineralization rate under Direct Photolysis than AZI due to the high absorption of UV radiation. For the EO processes, a low mineralization was found for all antibiotics, what was associated to a mass transport limitation related to the low contaminants concentration (200 µg/L). Besides that, an increase in mineralization was found, when HP and EO are compared, due to the influence of UV radiation that overcome the mass transport limitations. Although the UV-based processes control the reaction pathway that leads to mineralization, the best results to mineralize the antibiotics were achieved by PEO hybrid process. This can be explained by the synergistic effect of the processes that constitute them. A higher mineralization was achieved, what is an important and useful finding to avoid the discharge of microcontaminants in the environment.

Multidrug-resistant bacteria have become common all over the world, necessitating the development of new therapeutic strategies. Synergistic interactions between conventional antibiotics and natural bioactive may have therapeutic benefits in a clinical setting. There are plenty of medicinal plants that have proven efficacy against broad spectrum of microorganisms. The aim of the work was to assess the antibacterial activity of Cladanthus arabicus, a Moroccan medicinal plant, and Bubonium imbricatum, a Moroccan endemic plant. The evaluation of the synergistic effect of extracted essential oils (EOs) together with some conventional antibiotics was also investigated. Checkerboard test was used to evaluate the interaction of EOs in combination with amoxicillin and neomycin. The results showed that EOs contain a potent activity against the tested Enterobacteriaceae isolates, with inhibition zones values in the range of 8.05 ± 0.1 and 13.1 ± 0.11 mm and MIC values between 200 μg ml-1 to 800 μg ml-1 for C. arabicus and from 400 μg ml-1 to 1600 μg ml-1 for B. imbricatum respectively. Moreover, the current study allowed concluding that both EOs showed not only satisfactory antibacterial properties but also active effects combined with conventional antibiotics demonstrated by the Fractional Inhibitory Concentration Index (FICI). These findings are very interesting since there are no previous studies on synergistic interactions of these two plants with antibiotics. This article is protected by copyright. All rights reserved.

Elderly patients with underlying urological disease have a greater risk of urinary tract infections due to uncommon pathogens. The disease caused by Aerococcus has been underestimated, but mass spectrometry could be a simple method for identifying this pathogen. In this study, we report 2 cases of urinary tract infection by Aerococcus sanguinicola. A descriptive clinical-microbiological study was conducted on the presence of A. sanguinicola causing urinary tract infections. The presence of A. sanguinicola occurred in elderly patients with previous urological disease and a significant count in urine obtained through bladder catheterisation. Correct identification was achieved through mass spectrometry, and the clinical outcome of administering amoxicillin and cefuroxime was satisfactory. In this study, we also report the pathogenic capacity of A. sanguinicola. When there is a significant number of alpha-haemolytic microorganisms in the urine cultures, A. sanguinicola should be ruled out before reporting a result as urogenital microbiota.

The aims of this study were to determine the correlation of mutations in the ftsI gene (coding for PBP3) of Haemophilus influenzae with aminopenicillin resistance and to evaluate the 2017 European Committee for Antibiotic Susceptibility Testing (EUCAST) guidelines for clinical categorization of ampicillin, amoxicillin, and amoxicillin-clavulanate for strains with mutated PBP3 conferring resistance (rPBP3). A panel of 91 H. influenzae isolates was genetically characterized by sequencing of the fstI gene. For all the studied isolates, a screening with benzylpenicillin 1U (BP1) was carried out and minimum inhibitory concentrations (MICs) of ampicillin, amoxicillin, and amoxicillin-clavulanate were tested and interpreted according to EUCAST recommendations. ftsI sequence analysis revealed a total of 14 different amino acid substitutions in PBP3. The substitution patterns most commonly observed were [D350N, M377I, A502V, N526K] among the bla-positive rPBP3 strains (37.5%) and [D350N, A502T, N526K] among the bla-negative rPBP3 strains (24.5%). Screening with BP1 was able to correctly categorize 100% of the bla-negative sPBP3 strains, 100% of the bla-positive strains, and 92% of the bla-negative rPBP3 ones. Only 29% of the bla-negative rPBP3 strains evaluated displayed ampicillin MICs above the current EUCAST resistant breakpoint defined at 1 μg/ml. The PBP3 substitution patterns of the strains evaluated are similar to the ones observed in previous Spanish and European studies. Although the screening with BP1 proved to be adequate in the detection of bla-negative rPBP3 strains, these cannot be reliably identified by current 2018 EUCAST breakpoints for ampicillin.