Fluoroquinolones Enrofloxacin Research Articles

Population characteristics of pathogenic Escherichia coli in puerperal metritis of dairy cows in Ningxia region of China: a systemic taxa distribution of virulence factors and drug resistance genes.

Escherichia coli (E. coli) is closely associated with the occurrence of puerperal metritis in dairy cows. E. coli carries some the virulence and multi-drug resistant genes, which pose a serious threat to the health of postpartum cows. In this study, E. coli was isolated and identified from the uterine contents of postpartum cows with puerperal metritis in the Ningxia region of China, and its phylogenetic subgroups were determined. Meanwhile, virulence and drug resistance genes carried by E. coli and drug sensitivity were detected, and the characteristics of virulence and drug resistance genes distribution in E. coli phylogroups were further analyzed. The results showed that the isolation rate of E. coli in puerperal metritis samples was 95.2%. E. coli was mainly divided into phylogroups B2 and D, followed by groups A and B1, and was more connected to O157:H7, O169:H4, and ECC-1470 type strains. The virulence genes were mainly dominated by ompF (100%), traT (100%), fimH (97%), papC (96%), csgA (95%), Ang43 (93.9%), and ompC (93%), and the resistance genes were dominated by TEM (99%), tetA (71.7%), aac(3)II (66.7%), and cmlA (53.5%). Additionally, it was observed that the virulence and resistance gene phenotypes could be divided into two subgroups, with subgroup B2 and D having the highest distributions. Drug sensitivity tests also revealed that the E. coli was most sensitive to the fluoroquinolones enrofloxacin, followed by macrolides, aminoglycosides, tetracyclines, β-lactams, peptides and sulfonamides, and least sensitive to lincosamides. These results imply that pathogenic E. coli, which induces puerperal metritis of dairy cows in the Ningxia region of China, primarily belongs to the group B2 and D, contains multiple virulence and drug resistance genes, Moreover, E. coli has evolved resistance to several drugs including penicillin, lincomycin, cotrimoxazole, and streptomycin. It will offer specific guidelines reference for the prevention and treatment of puerperal metritis in dairy cows with E. coli infections in the Ningxia region of China.

Erbium(III) complexes with fluoroquinolones: Structure and biological properties

Four erbium(III) complexes with the fluoroquinolones enrofloxacin, levofloxacin, flumequine and sparfloxacin as ligands were synthesized and characterized by a wide range of physicochemical and spectroscopic techniques as well as single–crystal X–ray crystallography. The compounds were evaluated for their activity against the bacterial strains Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Xanthomonas campestris, which was higher than that of the corresponding free quinolones. The interaction mode of the complexes with calf–thymus DNA is via intercalation, as suggested by diverse studies such as UV–vis spectroscopy, DNA–viscosity measurements and competitive studies with ethidium bromide. Fluorescence emission spectroscopy revealed the high affinity of the complexes for bovine and human serum albumin and the determined binding constants suggested a tight and reversible binding of the compounds with both albumins.

Development of molecularly imprinted polymers and its magnetic version for the extraction of fluoroquinolones from milk

The aim of the present study is to develop selective extracting materials applicable to a diversity of fluoroquinolones. A series of Molecularly Imprinted Materials (MIPs) were prepared in order to choose the nature of the monomer and that of the porogen together with its ratio with the cross-linker. A non-regulated quinolone, Levofloxacin, was used as a template to avoid false positive results in its application. The resulting MIPs were evaluated in MISPE experiments for Enrofloxacin. The polymer prepared using methyl acrylate (MA) as a monomer and MeOH/CHCl3 (1:1, v/v) as a porogen provided the desired selectivity. Concretely, 100 μL (1.1 mmol) of MA as a monomer, 1.30 mL (9.8 mmol) of EGDMA (ethyleneglycol dimethacrylate) as a cross-linker, 31 mg (0.19 mmol) of AIBN (2,2′-azobis(2-methylpropionitrile)) as an initiator, were mixed with 85 mg (0.24 mmol) of levofloxacin as a template and 4 mL of MeOH/CHCl3 (1:1, v/v) as a porogen.The obtained optimized composition was upgraded to magnetic molecularly imprinted polymers (MMIPs) to be used as a dispersive-SPE extracting materials in the analysis of fluoroquinolones in milk. The selectivity of the resulting material for several fluoroquinolones (enrofloxacin, ciprofloxacin, sarafloxacin and norfloxacin) was studied. Finally, the MMIP was tested against real quinolone positive milk samples to evaluate its applicability.

Revision of fluoroquinolone breakpoints used for interpretation of antimicrobial susceptibility testing of canine bacterial isolates.

The fluoroquinolone antimicrobial agents, enrofloxacin and marbofloxacin, were US Food and Drug Administration (FDA) approved in the United States for use in dogs in 1988 and 1999, respectively. There have been many advances since then concerning the pharmacokinetic-pharmacodynamic (PK-PD) evaluation of fluoroquinolones, and there are data available on the susceptibility of targeted pathogens since the original approval. Using this information, the Clinical and Laboratory Standards Institute (CLSI) Veterinary Antimicrobial Susceptibility Testing Subcommittee (VAST) revised its antimicrobial susceptibility testing breakpoints. The previous breakpoints (used in older editions of CLSI standards) for enrofloxacin in dogs were susceptible (S), ≤ 0.5 µg/mL, intermediate (I) 1-2 µg/mL, and resistant (R) ≥ 4 µg/mL. The new breakpoints are S ≤ 0.06 µg/mL for a dose of 5 mg/kg, 0.12 µg/mL for a dose of 10 mg/kg, 0.25 µg/mL for a high dose of 20 mg/kg, and R ≥ 0.5 µg/mL. The breakpoints of 0.12 and 0.25 µg/mL represent a new susceptible-dose dependent (SDD) category. For marbofloxacin, previous breakpoints were S, ≤ 1 µg/mL, I 2 µg/mL, and R ≥ 4 µg/mL. The new breakpoints are S ≤ 0.12 µg/mL for a dose of 2.8 mg/kg, 0.25 µg/mL for a dose of 5.5 mg/kg (SDD), and R ≥ 0.5 µg/mL. The new breakpoints will be published in the next edition of CLSI-Vet01(S) and deviate considerably from the prior breakpoints. Laboratories are encouraged to revise their testing standards. These changes will likely reduce the unnecessary use of these fluoroquinolones in dogs.

Simultaneous Quantitative Determination of Eight Fluoroquinolones by High-Performance Liquid Chromatography with UV Detection using a C18 Monolithic Column

In the present work, an accurate and reliable reversed-phase liquid chromatographic method (RP-HPLC) for the simultaneous quantitative determination of eight fluoroquinolones (enoxacin, norfloxacin, ciprofloxacin, levofloxacin, moxifloxacin, enrofloxacin, sparfloxacin, and marbofloxacin) in bulk form and in pharmaceutical products is described. The optimum separation of the selected pharmaceutical compounds was achieved on a Chromolith® RP-18 endcapped column with a mobile phase consisting of acetonitrile and phosphate buffer (pH 5.5; 15 mM) pumped at 2 mL min-1. UV detection of all compounds was accomplished at 280 nm. The procedure was validated according to the International Conference on Harmonization (ICH) Q2 (R1) guideline. Good linear relationships were obtained (r ≥ 0.996) for all the analytes over their respective concentration ranges. Intra- and inter-day precision were less than 2 %. Recoveries were held in the range of 98 to 102 %. The developed method was successfully applied to the analysis of pharmaceutical products.

Bioaccumulation of antibiotics and resistance genes in lettuce following cattle manure and digestate fertilization and their effects on soil and phyllosphere microbial communities

The degradation and bioaccumulation of selected antibiotics such as the sulfonamide sulfamethoxazole (SMX) and the fluoroquinolones enrofloxacin (ENR) and ciprofloxacin (CIP) were investigated in soil microcosm experiments where Lactuca sativa was grown with manure or digestate (1%) and spiked with a mixture of the three antibiotics (7.5 mg/kg each). The soil, rhizosphere and leaf phyllosphere were sampled (at 0 and 46 days) from each microcosm to analyze the antibiotic concentrations, main resistance genes (sul1, sul2, qnrS, aac-(6’)-Ib-crand qepA), the intI1and tnpA mobile genetic elements and the microbial community structure.Overall results showed that SMX and CIP decreased (70-85% and 55-79%, respectively), and ENR was quite persistent during the 46-day experiment. In plant presence, CIP and ENR were partially up-taken from soil to plant. In fact the bioaccumulation factors were > 1, with higher values in manure than digestate amended soils. The most abundant gene in soil was sul2 in digestate- and aac-(6’)-Ib-cr in the manure-amended microcosms. In soil, neither sulfamethoxazole-resistance (sul1 and sul2), nor fluoroquinolone-resistance (aac-(6’)-Ib-cr, qepA and qnrS) gene abundances were correlated with any antibiotic concentration. On the contrary, in lettuce leaves, the aac-(6’)-Ib-cr gene was the most abundant, in accordance with the fluoroquinolone bioaccumulation. Finally, digestate stimulated a higher soil microbial biodiversity, introducing and promoting more bacterial genera associated with antibiotic degradation and involved in soil fertility and decreased fluoroquinolone bioaccumulation.

Introduction of maltodextrin nanosponges as green extraction phases: Magnetic solid phase extraction of fluoroquinolones

In the present work, for the first time, fully green maltodextrin nanosponges (MDNSs) as extraction phases for the preparation of magnetic sorbents were introduced. All of the raw materials and synthetic methodologies used to prepare MDNSs follow the principles of green chemistry. Fluoroquinolones (FQs) (ofloxacin, ciprofloxacin, enrofloxacin, and moxifloxacin) were used as model analytes to assess the extraction performance of MDNSs in magnetic solid-phase extraction (MSPE) procedure. Under the optimized conditions, the developed MSPE was coupled with HPLC-UV to sensitively quantify trace levels of four FQs in tap water, wastewater, and river water samples. The proposed MSPE-HPLC-UV method provided wide linearity in the range of 0.25–500.0 ng mL−1 with determination coefficients ≥0.9997. Low limits of detection (LODs ≤0.06 ng mL−1) and quantification (LOQs ≤0.20 ng mL−1) were achieved. Furthermore, the developed green extraction phases compared with all other maltodextrin-based extraction phases were promising.

Association between fluoroquinolone exposure and children's growth and development: A multisite biomonitoring-based study in northern China

BackgroundAlthough animal experiments found that antibiotic exposure during early life increased adiposity, limited human epidemiological evidence is available for the effects of veterinary antibiotic exposure on children's growth and development. ObjectiveThis study was conducted to examine the body burden of fluoroquinolones in northern Chinese children and assess its association with growth and development. MethodsAfter recruiting 233 children aged 0–15 years from 12 different sites in northern China in 2020, we measured urinary concentrations of 5 respective fluoroquinolones (fleroxacin, ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin) by high performance liquid chromatography. Categories of children's growth and development were identified based on the Z score of body mass index. The health risks of individual and combined antibiotic exposure were estimated by the hazard quotient (HQ) and hazard index (HI), respectively. The association between children's growth and development with antibiotic concentrations was evaluated via multiple logistic regression analysis. ResultsIn total, 4 antibiotics, fleroxacin, ofloxacin, ciprofloxacin, and enrofloxacin, were found in urine samples of northern Chinese children at an overall frequency of 57.08%. Due to diet and economic differences, antibiotic concentrations in urine samples differed by study area, and the highest concentrations were found in Tianjin, Henan, and Beijing. The percentage of the participants with HQ > 1 caused by ciprofloxacin exposure was 20.61%, and the HI values in 23.18% of samples exceeded 1, suggesting potential health risks. The odds ratio (95% confidence interval) of overweight or obesity risk of tertile 2 of enrofloxacin was 3.01 (1.12, 8.11), indicating an increase in overweight or obesity risk for children with middle-concentration enrofloxacin exposure. ConclusionThis is the first study to show a positive association of enrofloxacin internal exposure with overweight or obesity risk in children, demonstrating that more attention should be given to the usage and disposal of fluoroquinolones to safeguard children's health.

Formation of Salts and Molecular Ionic Cocrystals of Fluoroquinolones and α,ω-Dicarboxylic Acids.

The cocrystallization of the fluoroquinolones ciprofloxacin (cip), norfloxacin (nor), and enrofloxacin (enro) with the α,ω-dicarboxylic acids glutaric acid (glu), adipic acid (adi), pimelic acid (pim), suberic acid (sub), azeliac acid (az), and sebacic acid (seb) resulted in 27 new molecular salts and ternary molecular ionic cocrystals of compositions A+B–, A2+B2–, A2+B2–B, and A+B–A. Depending on the solvent, different stoichiomorphs, solvates, or polymorphs were obtained. All salts and cocrystals contain the robust R2NH2+...–OOC or R3NH+...–OOC synthon but have different supramolecular ring motifs. Moderate solubility enhancements over the parent fluoroquinolones were observed. Salts in the ratio of 1:1 and 2:1 were also prepared by ball-milling. The milled sample nor/az (1:1) was shown to gel the GRAS (generally recognized as safe) solvent propylene glycol, and enro/sub (1:1) was shown to gel both propylene glycol and water. Dynamic rheology measurements confirmed that nor/az and enro/sub behave like viscoelastic materials and supramolecular gels.

Detection and Dietary Exposure Assessment of Fluoroquinolones Residues in Chicken Meat from the Districts of Malang and Blitar, Indonesia

The purpose of this study was to determine the presence of fluoroquinolones (enrofloxacin and ciprofloxacin) residues in fresh chicken meat and evaluate its consumption risk to the adult population in Indonesia. A total of 55 fresh chicken-meat samples were collected from Districts of Malang and Blitar, East Java Province, Indonesia, in April 2017. Detections of enrofloxacin and ciprofloxacin were carried out using high-performance liquid chromatography equipped with a PDA detector. It was found that ciprofloxacin was detected with a frequency of 67.3% at a maximum concentration of 275.00 ng/g. Enrofloxacin was detected with a frequency of 41.8% at a maximum concentration of 242.40 ng/g, or totally as a sum of enrofloxacin and ciprofloxacin residues detected in 76.4% samples at a maximum concentration of 367.50 ng/g. The estimated dietary intakes of ciprofloxacin and enrofloxacin were 44.90 ng/kg body weight/day and 7.91 ng/kg body weight/day, respectively, resulting in the hazard indexes of 0.0063 and 0.0013 for the consumptions of ciprofloxacin and enrofloxacin residues in chicken meat. Therefore, the risk associated with the consumption of ciprofloxacin and enrofloxacin residues in chicken meat by the adult population in Indonesia was considered negligible.

High antimicrobial resistance in Salmonella spp. and Escherichia coli isolates from swine fecal samples submitted to a veterinary diagnostic laboratory in Colombia

Background: Commensal microflora such as Escherichia coli and Enterococcus spp. are representative indicators of antimicrobial resistance (AMR) as they are part of the normal intestinal microflora and can acquire and disseminate AMR to pathogenic or zoonotic bacteria like Salmonella spp. Objective: To investigate the state of AMR among E. coli and Salmonella spp., potential pathogens in humans, isolated from cecal contents of pigs submitted to a veterinary diagnostic laboratory in Colombia from 2016 to 2019. Methods: Susceptibility testing was conducted using the Kirby-Bauer disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines for antimicrobial zone diameter breakpoints. An E. coli strain (ATCC 25922) was used as the quality control organism. Isolates showing resistance to three or more antimicrobial classes were classified as multidrug-resistant (MDR) as defined by a joint group of the European Centre for Disease prevention and Control and the Center for Disease Control and Prevention of the USA. Results: A total of 112 E. coli and 192 Salmonella spp. colonies were isolated from 557 samples received between 2016 and 2019. In order of decreasing frequency, E. coli was resistant to tetracycline (100%), sulfamethoxazol-trimethoprim (97.5%), amoxicillin (86.4%), enrofloxacin (82.6%), tylosin (82.1%), doxycycline (59%), neomycin (50%), ciprofloxacin (45.5%), ceftiofur (35%), gentamicin (30%), tilmicosin (29%), and fosfomycin (12.5%). When compared with E. coli, Salmonella spp. was generally resistant to the same agents with slightly less resistance (between 10-30%) to eight of the antimicrobials tested. Salmonella spp. showed <20% resistance to three antimicrobials, as follows: neomycin (17%), gentamicin (16%), and fosfomycin (14%). Multi-resistance occurred in 68.7% (77/112) of E. coli and 70.3% (135/192) of Salmonella spp. isolates. Resistance of Salmonella spp. was alarming to all the critically important antimicrobials tested: fluoroquinolones (enrofloxacin, ciprofloxacin), ceftiofur (thirdgeneration cephalosporin), and macrolides (tylosin). Conclusions: According to our results, there is a high level of multidrug resistance (MDR) in E. coli and Salmonella spp. It is necessary to implement a nationwide antimicrobial resistance monitoring program in Colombia, together with proper antimicrobial prescribing guidelines for pigs. The indiscriminate use of antimicrobial growth promoters by the swine industry is generating widespread bacterial resistance and should be discontinued.

Phenotypic detection, antimicrobial susceptibility and virulence profile of staphylococci in the pig production setting, Makurdi, Nigeria.

Livestock, particularly pigs, have increasingly been recognized as important reservoirs for zoonotic transmission of pathogenic bacteria, including staphylococci. Livestock production systems in developing countries of sub-Saharan Africa, including Nigeria, are characterized by high misuse/abuse of antimicrobials and a close association between humans and these animals, which promotes the emergence and transmission of resistant and potentially virulent bacteria. In the present study, we investigated the occurrence and characteristics (species distribution, virulence and resistance profile) of staphylococci from smallholder backyard pig farms, slaughter slabs and pig handlers in Makurdi, Nigeria. A total of 330 nasal swabs originating from 300 pigs and 30 in-contact humans were collected and processed. One hundred and thirteen samples [34.2 %; 95 % confidence interval (CI): 29.1–39.6] comprising 103 (34.3 %; 95 % CI: 29.0–40.0) and 10 (33.3 %; 95 % CI: 17.3–52.8 %) samples from pigs and humans, respectively, were positive for staphylococci, yielding 120 isolates (pigs n=110, humans n=10). The 120 isolates were distributed into 15 species with Staphylococcus aureus (n=25) followed by Staphylococcus cohnii (n=19) and Staphylococcus sciuri (n=14) occurring more frequently. All isolates were resistant to β-lactam (100 %) antibiotics. Resistance to some critical antimicrobials, including linezolid (22 %), vancomycin (19.2 %), gentamicin (7.5%) and the fluoroquinolones ciprofloxacin (75.8 %) and enrofloxacin (66.7 %), was also observed. Majority (99.2 %) of the isolates displayed a multidrug resistance phenotype with the AMP-C-CIP-E-ENR-FOX-OX-P-S-SXT-TE phenotype being predominant. Overall, 70 % of the isolates expressed the methicillin resistance phenotype, out of which 20 % (n=17) were MRSA. Resistance to serum bactericidal activity and biofilm production were respectively observed in 45 (100 %) and 5 (11.3 %) of the coagulase-positive staphylococci. Our findings demonstrated the occurrence of a high diversity of staphylococci expressing multidrug resistance and potentially virulent phenotypes among healthy swine and pig handlers in small-scale backyard farms in North-Central Nigeria. These findings underscore the potential role of pig production settings in the emergence and dissemination of potentially virulent staphylococci and the importance of the development of antimicrobial resistance monitoring systems/implementation of control measures in developing countries. Proper hygienic practices and control of indiscriminate use and misuse of antibiotics are recommended.

Photodegradation of fluoroquinolones in aqueous solution under light conditions relevant to surface waters, toxicity assessment of photoproduct mixtures

Photochemical degradation of fluoroquinolones ciprofloxacin, enrofloxacin and norfloxacin in aqueous solution under light conditions relevant to surface waters at neutral and alkaline pH was found to proceed readily with half-lives between 0.9 and 2.7 min. The products of photochemical degradation identified by HPLC-MS included defluorinated, hydroxylated, and decarboxylated structures as well as structures with opened cyclic structures. For all of the studied substances, the reaction pathways were influenced significantly by the pH of the reaction system, with more products formed at alkaline pH than at neutral pH: the ratios of products in neutral and alkaline pH were 16/26, 9/19, 15/23 for ciprofloxacin, enrofloxacin, and norfloxacin, respectively. The structures of photoproducts and pathways of photochemical degradation are proposed. The antibacterial activities of photoproduct mixtures tested on E. coli and S. epidermidis were significantly higher in comparison to parental antibiotics in the case of both ciprofloxacin and enrofloxacin with p-values less than 0.0001 in most cases. The effect of the photoproducts was shown to be dependent on the pH value of the original antibiotic solutions before photodegradation: for ciprofloxacin, antibacterial activity against E. coli was more notably pronounced with regard to neutral pH photoproducts, while a less significant, or in one case not significant, effect of pH was observed against S. epidermidis; for norfloxacin, antibacterial activity against both E. coli and S. epidermidis was especially high with regard to alkaline pH photoproducts.

Characterization and Comparison of Enterococcus spp. Isolates from Feces of Healthy Dogs and Urine of Dogs with UTIs.

Simple SummaryInfections caused by Enterococcus spp. represent a serious threat to human and animal health due to difficulties in treatment. Indeed, these bacteria are a very able “trafficker” of antimicrobial resistance genes and for this reason they are often resistant to many antimicrobials. In this study we explored the role of pet dogs as possible carriers and targets of antimicrobial resistant and virulent enterococci. Isolates collected from feces of healthy animals and urine of dogs suffering with UTIs were characterized and compared. Strains resulted as resistant to many of the antimicrobials tested and almost of them were multidrug-resistant. Diffuse resistance was recorded for compounds routinely employed in human and pet therapy. Genes responsible for antimicrobial resistance were widely detected. E. faecalis and E. faecium resulted as equally distributed in stool samples, while E. faecalis prevailed among UTI isolates; virulence genes were more often detected in bacteria belonging to this species. Our data confirm that enterococci inhabitant of the gut flora probably represent the main source of UTI in dogs. Furthermore, healthy and sick pet dogs could be spreaders of antimicrobial and virulent enterococci, representing a possible hazard for other animals and owners.Enterococcus spp. are opportunistic pathogens of both humans and animals characterized by high resistance to antimicrobials. Dogs could be intestinal carriers or suffer from Enterococcus infections, mainly urinary tract infections (UTIs). This study aimed to analyze and compare Enterococcus spp. isolated from healthy dog stools and sick dog urine. Overall, 51 isolates (29 from stools and 22 from UTI) were characterized at species level and tested for antimicrobial resistance, biofilm production and presence of resistance and virulence genes. E. faecium and E. faecalis resulted as equally distributed in stools samples, while E. faecalis predominated among UTI isolates. HLAR phenotype was detected in 47.1% isolates; 64.7% isolates were resistant to ampicillin (47.1% with a MIC ≥ 64 µg/mL). High levels of resistance were recorded for fluoroquinolones (enrofloxacin 74.5%, ciprofloxacin 66.7%), clindamycin (84.3%), tetracycline (78.4%) and quinupristin–dalfopristin (78.4%). No vancomycin resistant strains were detected. All but one isolate were multidrug-resistant. Most detected resistance genes were tetM (70.5%), pbp4 (52.9%) and aph(3′)-IIIa (39.2%). All isolates were able to produce biofilm, but isolates from UTIs and belonging to E. faecalis more frequently resulted in strong biofilm producers. Most detected virulence genes were asa1 (52.9%), gelE (41.2%), cylA (37.3%) and esp (35.3%); all of them resulted as more frequently associated to E. faecalis. No particular differences emerged between isolates from feces and UTI, considering all evaluated aspects. Our results confirm pet dogs as carriers of multidrug-resistant enterococci; stool microflora could be considered as the most probable source of enterococcal UTI and E. faecalis carried by dogs seems to be more virulent than E. faecium, justifying its more frequent involvement in urinary tract infections.

Investigation of major amino acid residues of anti-norfloxacin monoclonal antibodies responsible for binding with fluoroquinolones

It is important to understand the amino acid residues that govern the properties of the binding between antibodies and ligands. We studied the binding of two anti-norfloxacins, anti-nor 132 and anti-nor 155, and the fluoroquinolones norfloxacin, enrofloxacin, ciprofloxacin, and ofloxacin. Binding cross-reactivities tested by an indirect competitive enzyme-linked immunosorbent assay indicated that anti-nor 132 (22–100%) had a broader range of cross-reactivity than anti-nor 155 (62–100%). These cross-reactivities correlated with variations in the numbers of interacting amino acid residues and their positions. Molecular docking was employed to investigate the molecular interactions between the fluoroquinolones and the monoclonal antibodies. Homology models of the heavy chain and light chain variable regions of each mAb 3D structure were docked with the fluoroquinolones targeting the crucial part of the complementarity-determining regions. The fluoroquinolone binding site of anti-nor 155 was a region of the HCDR3 and LCDR3 loops in which hydrogen bonds were formed with TYR (H:35), ASN (H:101), LYS (H:106), ASN (L:92), and ASN (L:93). These regions were further away in anti-nor 132 and could not contact the fluoroquinolones. Another binding region consisting of HIS (L:38) and ASP (H:100) was found for norfloxacin, enrofloxacin, and ciprofloxacin, whereas only ASP (H:100) was found for ofloxacin.

New chemiluminescent method of levofloxacin and ofloxacin determination based on terbium (III)-sensitized fluoroquinolone-KBrO3 reaction.

Fluoroquinolones can be oxidized with some agents, in this study selected fluoroquinolones (levofloxacin, ofloxacin, ciprofloxacin, norfloxacin, pefloxacin and enrofloxacin) were oxidized with potassium bromate in the presence of terbium (III) ions. According to the kinetic and spectral analysis of chemiluminescence emitted by the above systems, the terbium (III) ions were the only emitter. The excitation of the lanthanide ion was a result of the process of energy transfer from the products of fluoroquinolones oxidation to Tb(III) ions. The highest intensity of chemiluminescence was obtained for levofloxacin and ofloxacin containing an alkoxy substituent at C-8 in the quinoline ring. The chemiluminescence intensity was correlated linearly (r= 0.9994) with the concentration of ofloxacin (or levofloxacin) in the range 1 × 10-6 to 4 × 10-5 mol L-1 ; the detection limit was 3 × 10-7 mol L-1 for both fluoroquinolones. In the optimized conditions, the chemiluminescence of the levofloxacin (or ofloxacin)-Tb(III)-KBrO3 -H2 SO4 systems was used to determine these compounds in a mixture of fluoroquinolones and in pharmaceuticals.

Monitoring of pharmaceuticals in aquatic biota (Procambarus clarkii) of the Doñana National Park (Spain)

In this work the presence of different pharmaceuticals at Doñana National Park (Spain) and their main entry sources (input source or entry points) have been stated over the 2011–2016 years period. Twenty-three selected pharmaceuticals (corresponding to eight therapeutic families) were evaluated in crayfish and water samples from Doñana National Park (Spain) (six sampling points selected in order to cover different possible pollution sources into and surrounding the Park). The multiresidue determination was carried out using enzymatic-microwave assisted extraction prior to high performance liquid chromatography mass spectrometry detection. Sulphonamides (sulfadiazine, sulfamerazine, sulfamethazine, and sulfamethoxazole); trimethoprim, an antibiotic that is frequently co-administered with sulfamethoxazole; amphenicols (chloramphenicol, florfenicol and thiamphenicol); fluoroquinolones (ciprofloxacin, enrofloxacin, flumequine, danofloxacin, gatifloxacin, norfloxacin, marbofloxacin and grepafloxacin); penicillins (amoxicillin); tetracyclines (chlortetracycline and oxytetracycline); non-steroidal anti-inflammatory drugs (salicylic acid and ibuprofen); beta-blocker drugs (atenolol); and antiepileptics (carbamazepine) were analysed. Ciprofloxacin, ibuprofen, salicylic acid, flumequine, and carbamazepine were detected and/or quantified at some of the selected sampling points. A clear ecotoxicological risk to the ecosystem was demonstrated from the occurrence of ciprofloxacin in samples obtained after the punctual and massive presence of people inside the Park. Furthermore, flumequine and carbamazepine have been detected in Procambarus clarkii specimens in concentrations around 30 ng g−1 and 14 ng g−1, respectively, and their occurrence in the specimens could indicate the persistence of the discharge sources. The main source of pharmaceuticals into the Park might be the livestock farming activities, and the influence of urban wastewaters from surrounding villages does not seem to be very important.

Detection of qnrS and tetA resistance coding genes in Pseudomonas aeruginosaof egg-laying hens farmin Cianjur Regency, West Java

The use of antibiotics is an alternative to reduce disease incidence and is used to increase egg-laying hens. This study aims to detect the presence of antibiotic resistance to resistance coding genes in Pseudomonas aeruginosa bacteria. The cloacal swab samples were collected randomly as many 66 samples from several egg-laying hens farms in Cianjur Regency, West Java. The collected isolates were examined bacteriologically. The results of the antibiotic sensitivity test of 8 samples (12.1%) of the Pseudomonas aeruginosa showed the resistance level of antibiotics class tetracycline (tetracycline50%, oxytetracycline75%, and doxycycline50%), fluoroquinolone (enrofloxacin 12.5%), and phenicol (chloramphenicol 12.5%). Pseudomonas aeruginosa was resistant to tetracyclines, oxytetracyclines, doxycycline, enrofloxacin and is sensitive to chloramphenicol. The detection of resistance coding genes showed the genes amount of tetA (62.5%) and qnrS (75%). Efforts to determine the level of resistance and use of antibiotics in farms need regular surveillance and monitoring to ensure the wise use of antibiotics.

Facile synthesis of cobalt-iron layered double hydroxides nanosheets for direct activation of peroxymonosulfate (PMS) during degradation of fluoroquinolones antibiotics

How to efficiently and fast remove the serious perniciousness of the residual antibiotics in water environment is crucial for protecting ecosystem. Herein, we reported the Fenton-like system based on layered double hydroxides (LDHs) nanosheets for direct peroxymonosulfate (PMS) activation efficient for fast removing the typical five fluoroquinolones antibiotics ciprofloxacin (CIP), norfloxacin (NOR), levofloxacin (LEV), enrofloxacin (ENR) and ofloxacin (OFL). A series of CoFe-LDHs nanosheets was one-step fabricated by integrating coprecipitation and in-situ exfoliation method. The as-obtained CoFe-LDHs nanosheets catalysts exhibit thin nanosheets (~3 nm) with high redox properties, abundant oxygen vacancies, appreciable adsorption capacity, remarkable catalytic performance and favorable stability. The variable valent state, cheap, easy-to-obtain and low-toxic Co and Fe elements were used to construct stable LDHs for efficient activation of PMS to degrade quinolone antibiotics. Among them, Co1Fe1-LDHs nanosheets exhibited the best CIP degradation efficiency of 86.9% within 12 min, which is superior to most of previous candidates. The impacts of different reaction parameters, catalyst stability, main reactive oxygen species, the main CIP degradation mechanism and rational degradation pathways were systematically studied. This work offers a feasible strategy to tune the performance of LDHs-based materials in Fenton-like system degradation of antibiotics.

Veterinary Drug Residues in Beef, Chicken, and Egg from Ghana

The use of veterinary drugs on farm animals has the potential of generating drug residues in edible animal products that may affect public health. Veterinary drug residues in 144 samples including beef, chicken, and egg were measured using ultra-high-performance liquid chromatography in tandem with a triple quadrupole mass spectrometer. Sixty-three percent of the samples had quantifiable multiple detections of veterinary drug residues. The mean amounts of the tetracyclines (tetracycline, oxytetracycline, and chlortetracycline) residues in the samples were 81.35 μg/kg, 76.94 μg/kg, and 234.43 μg/kg, respectively. The mean β-lactam (amoxicillin, cefazolin, and penicillin G) residues were 35.76 μg/kg, 47.02 μg/kg, and 41.02 μg/kg respectively. The mean residues of the sulphonamides (sulfamethoxazole, sulfadoxine, and sulfathiazole) were 103.98 μg/kg, 46.05 μg/kg, and 68.63 μg/kg respectively. The mean fluoroquinolone (enrofloxacin) concentration was 30.19 μg/kg. The mean residue concentrations of salbutamol, erythromycin, prednisone, ketoprofen, and haloperidol were 6.32, 77.18, 23.66, 14.94, and 9.62 μg/kg respectively. The exposure estimations conducted on residues whose concentrations exceeded their maximum residue limits shows that consumers are at risk of acute exposure to tetracycline in egg, and cefazolin, penicillin G, sulphamethoxazole, salbutamol, prednisone, and haloperidol which may be injurious to the health and wellbeing.