Quinolone Research Articles

Temporal and spatial variability of antibiotics in agricultural soils from Huang-Huai-Hai Plain, northern China

The objective of this study was to investigate the temporal and spatial distribution of antibiotics in agricultural soils of Huang-Huai-Hai Plain, which is a major agricultural producing area and economically developed region in China. In this study, 105 soil samples including 13 groups of soil profile samples (0–20, 20–40 and 40–60 cm) and 23 paired surface soil samples of greenhouse and open-field were collected from four provinces/municipality in 2018. The occurrence of 20 antibiotics, including four tetracyclines (TCs), seven quinolones (QNs), six sulfonamides (SAs) and three macrolides (MLs) were measured. The concentrations of total antibiotics fell in the range of 1.62–575 μg kg−1, with the mean value of 68.8 μg kg−1. TCs and QNs were dominant antibiotics in soil, accounting for 99.6% of the total concentration. Regional differences of antibiotic residues in soil were found among the four regions as well as between different cropping systems. The levels of antibiotics in greenhouse soils (3.52–575 μg kg−1) were higher than those in open-field soils (1.62–142 μg kg−1). In soils of greenhouse of 1–6 years old, the levels of antibiotics were higher than those with longer history (7–30 years). Antibiotics were mainly distributed in the depth of 0–20 cm. The total concentrations of antibiotics/QNs followed the order of 0–20 cm > 40–60 cm > 20–40 cm, due to probably their interactions with total organic carbon and associated bacterial communities. The results in the study will provide data supports for the formulation of soil antibiotic contamination prevention and control measures.

Copper nanoclusters as a turn-on fluorescent probe for sensitive and selective detection of quinolones

As a new type of fluorescent probe, metal nanoclusters have a broad application prospect in optical sensors and biosensors. In the present study, copper nanoclusters (CuNCs) have been synthesized by etching non-luminescent copper nanoparticles with excess cysteine (Cys). The as-prepared cysteine stabilized turquoise emitting copper nanocluster (Cys-CuNCs) exhibited strong fluorescence emission, and could be quenched by Fe3+ ions. After adding quinolones (QNs) to the quenching system, the fluorescence intensity of Cys-CuNCs was restored. A novel Cys-CuNCs-Fe3+ sensor for the detection of QNs, such as ofloxacin (OFL) and norfloxacin (NOR), was constructed based on the fluorescence turn-on strategy. The linear range of the proposed method is 0.5–40 μM for OFL and 0.5–50 μM for NOR, and the detection limits of OFL and NOR are all 50 nM. As a cost-effective, high selectivity and sensitivity sensor tool, the Cys-CuNCs-Fe3+ sensor had been successfully applied to detect QNs in tablets and human urine.

Bioaccumulation Characteristics of Quinolones (QNs) in Dominant Fish Species and Their Correlation with Environmental Factors in Baiyangdian Lake

In recent years, quinolone antibiotics (QNs), which easily bioaccumulate in aquatic organisms, have been widely detected in lake ecosystems, and the bioaccumulation and trophic transfer behavior are obviously spatiotemporally different. In this study, the bioaccumulation and trophic transfer behavior of fourteen QNs in nine dominant fish species were studied, the correlation with environmental factors was analyzed, and the health risk of QNs was evaluated in Baiyangdian Lake. The results showed that the mass concentrations of ∑QNs in water varied from 0.7400 to 1590 ng·L-1. Furthermore, the detected frequencies of flumequine (FLU), oxolinic acid (OXO), and ofloxacin (OFL) were higher, and the average mass concentration of FLU was the highest. The content of ∑QNs in fish ranged from 17.1 to 146 ng·g-1, and the average contents of ciprofloxacin (CIP) and OFL were higher. The bioaccumulation factors (BAF) were in the range of 96.2 (BAFMAR)-489 (BAFCIP) L·kg-1, indicating the bioaccumulation of QNs was low in dominant fish species. The trophic magnification factors (TMF) of five QNs (enrofloxacin (ENR), FLU, marbofloxacin (MAR), norfloxacin (NOR), and OFL) varied from 0.714 (TMFMAR) to 1.33 (TMFENR), indicating ENR exhibited trophic magnification, while FLU, MAR, and ∑QNs exhibited trophic dilution. The results of correlation analysis between environmental parameters and BAF/TMF showed that pH, T, SD, DO, COD, TP, TN, NH4+-N, NO3--N, and PO43--P were significantly related to the bioaccumulation of QNs in fish. The results of human health risk showed that the hazard quotient (HQ) of CIP (0.0040-0.026) was significantly higher than that of other QNs (≤ 0.0050), and the hazard indices (HI) ranged from 0.0010 to 0.035, indicating a high level of health risk. Therefore, to reduce the health risk, the standard and residue limits of QNs should be set in Baiyangdian Lake.

Environmentally Friendly Quinolones Design for a Two-Way Choice between Biotoxicity and Genotoxicity through Double-Activity 3D-QSAR Model Coupled with the Variation Weighting Method.

Quinolone (QN) antibiotics are widely used, which lead to their accumulation in soil and toxic effects on ryegrass in pasture. In this study, we employed ryegrass as the research object and selected the total scores of 29 QN molecules docked with two resistant enzyme structures, superoxide dismutase (SOD, PDB ID: 1B06) and proline (Pro, PPEP-2, PDB ID: 6FPC), as dependent variables. The structural parameters of QNs were used as independent variables to construct a QN double-activity 3D-QSAR model for determining the biotoxicity on ryegrass by employing the variation weighting method. This model was constructed to determine modification sites and groups for designing QNs molecules. According to the 3D contour map of the model, by considering enrofloxacin (ENR) and sparfloxacin (SPA) as examples, 23 QN derivatives with low biotoxicity were designed, respectively. The functional properties and environmental friendliness of the QN derivatives were predicted through a two-way selection between biotoxicity and genotoxicity before and after modification; four environmentally friendly derivatives with low biotoxicity and high genotoxicity were screened out. Mixed toxicity index and molecular dynamics methods were used to verify the combined toxicity mechanism of QNs on ryegrass before and after modification. By simulating the combined pollution of ENR and its derivatives in different soils (farmland, garden, and woodland), the types of combined toxicity were determined as partial additive and synergistic. Binding energies were calculated using molecular dynamics. The designed QN derivatives with low biotoxicity, high genotoxicity, and environmental friendliness can highly reduce the combined toxicity on ryegrass and can be used as theoretic reserves to replace QN antibiotics.

Clinical characteristics analysis of patients with pneumonia infected by Chlamydia psittaci

To explore the clinical characteristics of pneumonia infected by Chlamydophila psittaci (C. psittaci). A retrospective analysis was performed on 3 cases of C. psittaci pneumonia admitted to People's Hospital of Tongling City from July 2019 to January 2020. The patients' contact history, clinical manifestations, laboratory examination, imaging characteristics and evolution, etiology, treatment process and outcome were analyzed, so as to provide experience for the diagnosis and prevention of C. psittaci pneumonia. The 3 patients had been infected through pet or zoonotic exposures. All symptoms included high fever (body temperature > 39 centigrade), cough, sputum, chest tightness and dyspnea. The disease progressed rapidly, with severe acute respiratory distress syndrome (ARDS) and shock as the main manifestations, but the damages to the heart, liver and kidney were mild. Laboratory tests showed that C-reactive protein (CRP, all > 200 mg/L) and neutrophil proportion (Neut%, > 0.90) were significantly increased, while white blood cell count (WBC) and procalcitonin (PCT) were not significantly increased. Chest computed tomography (CT) showed inflammatory infiltration with interstitial changes, either unilateral or bilateral. Chest X-ray showed large areas of inflammatory infiltrations, fan-shaped or wedge-shaped to the edge of pleura. After 7 days of treatment, the bedside computed X-ray (CR) showed absorption of infiltration. After 11-13 days, the CT reexamination indicated lung infection was basically absorbed. Metagenomic next-generation sequencing (mNGS) confirmed the presence of C. psittaci in patients' sputum. It was sensitive to quinolones and tetracyclines. The patients' body temperature dropped to normal after 2-3 days of antibiotics, and all patients were extubated and transferred to normal ward 10 days later. The total course of illness was 20-30 days. The patients with C. psittaci pneumonia are critically ill, and clinical manifestations of moderate to severe ARDS and shock are common. Early diagnosis depends on mNGS, and reasonable treatment is important for prognosis.

A study of bacterial pathogens obtained from various samples in a tertiary care hospital and their antimicrobial susceptibility patterns

Background: Antimicrobial resistance (AMR) is of great concern in recent years as it is posing a global threat. The present study was undertaken to identify the prevalence of common bacterial isolates and their antimicrobial susceptibility patterns and to tackle the AMR by strict implementation of antibiotic stewardship programme (AMSP). Methods: We prospectively studied the microbiome and its antibiotic susceptibility patterns from various clinical samples at our tertiary care hospital, from January to June 2018. All samples were processed as per standard protocols. Antibiotic susceptibility testing was performed using Kirby–Bauer disc diffusion method as per the Clinical and Laboratory Standards Institute 2016 guidelines. Results: Escherichia coli was the predominant organism followed by Klebsiella spp, Acinetobacter spp and Pseudomonas spp. More than 50% resistance was observed to third generation cephalosporins and quinolones in all Gram negative isolates. Methicillin-resistant Staphylococcus aureus and methicillin-resistant coagulase negative Staphylococcus constituted 41% and 54% respectively. Vancomycin intermediate-sensitive S. aureus/vancomycin resistance S. aureus were not evident. Vancomycin-resistant enterococci (n = 10) were also isolated, but all were sensitive to linezolid. Conclusions: The present study highlights the alarming development of multidrug-resistance to almost all the drugs with a very few exceptions. Continuous and periodic evaluation of bacteriological profile and its susceptibility patterns are helpful in formulating appropriate antibiotic policy to tackle the AMR.

Combined toxicity characteristics and regulation of residual quinolone antibiotics in water environment

In this study, the mixture toxicity index method was used to evaluate the combined toxicity of residual Quinolones (QNs) on algae in twelve groups of water environment reported in the literature. The selected three sets of data (II, Ⅺ, and Ⅻ) combined with full factorial design method were used to analyze the significance of the combined toxicity. Subsequently, molecular docking was used to reveal the significant mechanism of the primary effect of the combined toxicity. Finally, based on the sensitivity analysis method, the acid-base conditions affecting the combined toxicity were screened, and molecular dynamics simulation was used to control the combined toxicity in the water environment. The results of the mixture toxicity index method showed that the combined toxicity in all the twelve groups of water environments was synergistic. The full factorial design method revealed that ciprofloxacin, norfloxacin, enrofloxacin, lomefloxacin, and their binary combinations from the combined toxicity system of QNs, were the significant factors that caused the synergistic toxicity of QNS on algae. Molecular docking confirmed that the total number of amino acids, the number of significant amino acids, and hydrogen bonds of QNs toxic targets were significantly related to the synergistic effect of the combined toxicity. In addition, the molecular dynamics simulation showed that the binding energy of residual QNs and toxic targets changes with the acid-base conditions of the water environment. Thus, the combined toxicity can be slowed down or reduced by adequately adjusting the acid-base condition of the water.

Multi-phase distribution, spatiotemporal variation and risk assessment of antibiotics in a typical urban-rural watershed

The widespread consumption and continuous discharge of antibiotics have threatened the ecological health of urban-rural watershed. In this study, multi-phase distribution, spatiotemporal variation and ecological risk of 18 antibiotics in rivers and lakes from Suzhou City were investigated based on urban-rural gradient. The total antibiotic concentration in surface water, suspended particulate matter (SPM) and sediments was 39.28–2578 ng/L, 6.16–171.09 ng/L and 12.67–2249 ng/g, respectively. High detection frequency (>76%) and concentration of antibiotics in multi-phase suggested universal pollution. Quinolones (QNs) and tetracycline (TCs) were the dominant antibiotics detected. The partitioning coefficient (KP) value of SPM-water was 1.43–29.93 times larger than sediment-water, indicating that SPM can greatly affect the fate and distribution of antibiotics. Significant positive correlations between antibiotics and environmental parameters (e.g. TOC, TP and TN) revealed combined contamination and similar pollution sources. Antibiotic pollution exhibited evident spatiotemporal variation. For spatial variation, urban area showed more serious antibiotic pollution and greater ecological risk than rural and suburb areas, especially for sediments. Besides, antibiotic level and risk in rivers were higher than lakes. For seasonal variation, in case of surface water, rural area exhibited higher content in winter, while greater content was detected in autumn and spring in urban and suburb areas, respectively. The highest antibiotic content in SPM and sediments was all measured in winter owing to weak degradation ability. Ecological risk assessment based on risk quotients (RQs) indicated that norfloxacin (NFX), ciprofloxacin (CFX) and anhydroerythromycin (ETM-H2O) in surface water presented medium to high risk throughout the entire year, while sulfadiazine (SDZ) and enrofloxacin (EFX) in sediments showed higher accumulation potential. Thus, these five antibiotics were selected as the priority antibiotics for pollution control. In short, this study improves the understanding of antibiotic fates in the urban-rural watershed and provides scientific basis for the authorities to regulate antibiotic pollution.

Enrichment of antibiotics in an inland lake water

Inland water is very susceptible to the input of pollutants. However, little is known about the occurrence of antibiotics in inland lakes. In this study, a total of 83 target antibiotics were quantified in water and sediment samples collected from the Qinghai Lake, the largest inland lake of China located on the northeast of Qinghai-Tibet plateau, and its inflowing rivers. The results showed that 27 and 25 antibiotics were detected in water and sediments, respectively, with the summed concentrations (SUM) of 1.14–17.3 ng/L and 0.72–8.31 ng/g. Compared with the input rivers, significantly higher levels of sulfonamides (SAs), quinolones (QNs), polyethers (PEs), and SUM in water samples were observed in Qinghai Lake water. The average proportions of SAs (50.9–52.7%) and QNs (22.0–28.3%) in Qinghai Lake water nearly doubled compared to those in input rivers. An enrichment factor (EF) was proposed to reveal the enrichment degree of antibiotics in Qinghai Lake compared to its input river water. Sulfaguanidine (SGD), flumequine (FLU), and nalidixic acid (NDA) were enriched in Qinghai Lake up to several ten times based on the calculated EF values, due to their persistence in such a cold saline lake. Risk assessment showed that most antibiotics except anhydrochlortetracycline (ACTC) had insignificant risks to aquatic organisms and antibiotic resistance selection in Qinghai Lake water. This study was the first to reveal the enrichment of antibiotics in Qinghai Lake water, and suggests the urgent need to investigate the possible long-term enrichment and environmental risks of antibiotics in inland lakes.

Simultaneous determination of 18 quinolone residues in marine and livestock products by liquid chromatography/tandem mass spectrometry

A simple and efficient LC/ESI/MS/MS method was developed to determine 18 (fluoro)quinolone (QNs) residues in milk, chicken, pork, fish and shrimp. This method is capable of screening and confirming the presence of 12 amphoteric QNs (marbofloxacin, norfloxacin, enrofloxacin, ciprofloxacin, desethylene ciprofloxacin, lomefloxacin, danofloxacin, sarfloxacin, difloxacin, ofloxacin, orbifloxacin and enoxacin) and 6 acidic QNs (oxolinic acid, nalidixic acid, flumequine, cinoxacin, piromidic acid and pipemidic acid). The drugs were extracted from matrix with acetonitrile containing 1% formic acid, diluted in 10% acetonitrile and defatted by extraction with hexane. The LC separation was conducted on an XDB C-8 (150 mm x 4.6 mm, 5 μm) column with gradient elution of 20 mM ammonium formate in 0.1% formic acid-acetonitrile as the mobile phase. Mass spectrum acquisition was completed in the positive ion mode by applying multiple reaction mode (MRM). The decision limit (CCα) and detection capability (CCβ), stated in the Decision No. 2002/657/EC and the ISO standard No.11843, have been calculated in the case of nonauthorized substance. The values of CCα ranged from 0.18 to 0.68 ng/g and CCβ ranged from 0.24 to 0.96 ng/g under specified conditions.

Distribution and potential risk assessment of antibiotic pollution in the main drinking water sources of Nanjing, China.

The distribution character of 41 antibiotics belonging to 6 groups, sulfonamides (SAs), quinolones (QUs), tetracyclines (TCs), macrolides (MLs), penicillins (PLs), and chloramphenicol (CHL), was investigated in drinking water sources of Nanjing during 2017-2019. MLs (42.98%) were the most abundant category, followed by SAs (25.94%) and QUs (22.52%). The dominant antibiotic was ofloxacin (OFX) in Dec. 2017 (average concentration, 3.14ng/L; range, ND-35.20ng/L) and Nov. 2018 (2.16ng/L, ND-12.26ng/L), and sulfadiazine (SDZ) in Mar. 2019 (16.37ng/L, ND-25.90ng/L). For Dec. 2017, the total concentrations in Zhongshan Waterworks (S15) and Jinniushan Reservoir (S16) were significantly higher than the other sampling sites, which may be attributed to point source pollution. The ecological and human risk of the main antibiotics was assessed by risk quotients (RQs) and target hazard quotient (THQ), respectively. Most of the RQ values were below 0.1, except enrofloxacin (ERX, 0.11) and enoxacin (ENX, 0.62) in Dec. 2017, lomefloxacin (LOM, 0.14) in Nov. 2018, and LOM (0.28) and ERX (0.10) in Mar. 2019. This indicated that the risk of the target antibiotics to aquatic organisms in the 3years was moderate or low level. Meanwhile, results of the THQ values showed that antibiotic exposure caused no risk to human health. This research provides scientific information for antibiotic pollution control and enriches environmental monitoring data in the drinking water sources.

Strategic photosafety screening system consisting of in chemico photoreactivity and in vitro skin exposure for quinolone derivatives

The main objective of this study was to verify the applicable domain of a proposed photosafety screening system, consisting of a reactive oxygen species (ROS) assay and in vitro skin permeation test, for dermally-applied chemicals. Quinolones (QNLs) were selected as test compounds, including enoxacin, flumequine, moxifloxacin, nalidixic acid, orbifloxacin, and oxolinic acid. The ROS assay and in vitro skin permeation test were employed to evaluate photoreactivity and skin deposition of QNLs, respectively. All QNLs exhibited significant ROS generation on exposure to simulated sunlight; in particular, enoxacin was indicative of potent photoreactivity compared with the other 5 QNLs. Steady-state concentration values of flumequine and nalidixic acid were calculated to be 5.0 and 8.2 μg/mL, respectively, and higher than those of the other QNLs. Based on the photoreactivity and skin exposure of QNLs, the phototoxic risk was ranked, and the predicted phototoxic risk by the proposed system was mostly in agreement with observed in vivo phototoxicity, suggesting the applicability of the proposed strategy to photosafety assessment of QNLs. The proposed screening would be efficacious to predict phototoxic risk of dermally-applied chemicals.

Changes in epidemiologic characteristics and antimicrobial resistance of Streptococcus pyogenes isolated over 10 years from Japanese children with pharyngotonsillitis.

Introduction. Pharyngotonsillitis caused by Streptococcus pyogenes (group A streptococci, or GAS) is among the most common infections treated with antibiotics in pediatric patients.Aim. This study aimed to analyse changes in molecular epidemiology and antibiotic susceptibility among GAS isolates in three study periods spanning 10 years.Methodology. GAS isolated from paediatric patients with pharyngotonsillitis during Period I (mid-2007 to 2008, n=235), Period II (2012, n=210), and Period III (2018, n=189) were analysed for emm type, multilocus sequence type (MLST), antibiotic susceptibility, and macrolide (ML)- and quinolone (QL)-resistance genes.Results. Over 20 % of isolates represented emm1 and emm12 types, remaining common in all three periods. Among other emm types, emm4 was common in Period I, emm28 and emm89 in Period II, and emm3 and emm89 in Period III. All isolates remained highly susceptible to penicillins and cephalosporins. Isolates possessing mefA, ermA, or ermB genes mediating ML resistance increased from 34.9 % in Period I to 60.9 % in Period II, but fell to 27.5 % in Period III. QL-resistant isolates with amino acid substitutions affecting ParC and/or GyrA gradually increased from 11.5 to 14.3 %. Specific sequence types identified by MLST and emm typing were associated closely with ML or QL resistance.Conclusion. Our findings indicate that even in ambulatory care, antibiotic choice for these infections should be based on rapid identification and characterization of causative pathogens.

Establishment of a database of in vitro combined drug efficacy against multi-drug resistant Gram-negative bacilli

Objective To study the synergistic and additive effects of commonly used antibiotics on multi-drug resistant Gram-negative bacilli and to establish a database of combined pharmacodynamics in vitro. Methods Seven antibiotics including fosfomycin (PHOS), levofloxacin (LEV), ceftazidime (CAZ), compound sulfamethoxazole (SMZ), piperacillin/tazobactam (TZP), cefoperazone/sulbactam (SCF) and imipenem (IMP) were selected and grouped into 21 drug pairs. Based on the results of extended spectrum β-lactamases (ESBLs) test and modified carbapenem inactivation method (mCIM), a total of 172 strains of multidrug-resistant Gram-negative bacilli were divided into four groups: 20 strains of carbapenem-resistant Klebsiella pneumoniae (group A), 50 strains of pan-resistant Acinetobacter baumannii (group B), 62 strains of ESBLs-producing Enterobacter (group C) and 40 strains of carbapenem-resistant Pseudomonas aeruginosa (group D). Chessboard dilution method was used to detect the in vitro combined efficacy of 21 drug pairs on drug-resistant bacteria from the four groups. Whonet 5.6 was used for statistical analysis. Results All 172 strains were single drug resistant to the seven antibiotics. Results of the combined drug efficacy test showed that no antagonism was found in the four groups. In group A, ten drug pairs, especially the combination of PHOS+ LEV (30%, 6/20), had synergistic effects and 14 showed partial synergistic effects, but no additive effect was detected. Synergistic effects, partial synergistic effects and additive effects were respectively achieved by 12, ten and three drug pairs in group B. The LEV+ SMZ combination had synergistic effects against 56% (28/50) of the strains, which was the highest among all combinations. There were 14, 17 and 16 drug pairs showing synergistic effects, partial synergistic effects and additive effects in group C, respectively, and the strongest synergistic effects were achieved by the IMP+ LEV combination (30.6%, 19/62). There were 12, 14 and 13 drug pairs having synergistic effects, partial synergistic effects and additive effects in group D, respectively, and the strongest synergistic effects were achieved by the IMP+ LEV combination (20%, 8/40). Conclusions The combined use of quinolones, carbapenems, sulfonamides and PHOS could have good synergistic effects against multi-drug-resistant gram-negative bacilli. Monitoring the in vitro combined efficacy before treatment would improve the accuracy of antibiotic use and is of great clinical value. Key words: Multi-drug resistance; Antibiotics; Gram-negative bacilli; Combined drug efficacy; Synergistic effect; Additive effect

Changes in abiotic dissipation rates and bound fractions of antibiotics in biochar-amended soil

To understand the impacts of molecular structures and biochar types on abiotic dissipation and bound fractions of antibiotics in soil, nine biochar types were applied into a soil contaminated with 16 antibiotics. In soil without biochar, the abiotic dissipation rates of antibiotics were generally tetracyclines (TCs) > sulfonamides (SAs) > quinolones (QLs). The trend was quite consistent with the total amounts of oxygen (O), nitrogen (N) and/or sulphur (S) atoms in antibiotic molecular structures. The dissipation trends of TCs (excluding oxytetracycline) and QLs (excluding ofloxacin) were just opposite the order of their logKow values, indicating that hydrophobic adsorption played the key role in their abiotic dissipation. The reason why oxytetracycline and ofloxacin were unique is they had one more O-containing functional group, when compared with the other TCs and QLs, respectively, resulting in their different hydrophobic adsorption affinities. For SAs, sulfadiazine and sulfachinoxalin had the highest and lowest abiotic dissipation rates, respectively. QLs and TCs were the dominant tightly bound fractions, while molecular structures influenced the bound fractions of SAs. In biochar-treated soils, biochars produced at 250 °C generally had a positive effect on the abiotic dissipation rates of antibiotics. The effect sizes of biochars produced at 400 °C and 600 °C for the abiotic dissipation of antibiotics were influenced by both biochar type and antibiotic molecular structure. Biochar type had the strongest impact on SA bound fractions, followed by TCs, while it had minimal influence on QLs. Biochars generally decreased the apparent distribution coefficients (Kapp) of antibiotics in soil, indicating an increase in antibiotic leaching following biochar addition.

Bioaccumulation, trophic transfer, and human health risk of quinolones antibiotics in the benthic food web from a macrophyte-dominated shallow lake, North China

The bioaccumulation and trophic transfer of 12 Quinolones (QNs) have been studied in a macrophyte dominated lake-Baiyangdian Lake, China. QNs concentrations were detected in surface water, sediments, and 25 biological samples. The average concentrations of QNs varied from 3.01 ng/L for Oxolinic Acid (OXO) to 174 ng/L for Flumequine (FLU) in water, 3.28 ng/g (dry weight, dw) for OXO to 97.0 ng/g (dw) for FLU in sediments, and from 2.88 ng/g (dw) for Pipemidic Acid (PIP) to 37.7 ng/g (dw) for FLU in biological samples. The values of bioconcentration factors (BCFs) or bioaccumulation factors (BAFs) (in the range of 98.0–723 L/kg) and biota sediment accumulation factor (BSAFs) (in the range of 0.000300–0.124) were indicated that low bioaccumulation ability of target QNs in biological species. Due to the detected frequencies of FLU, Enrofloxacin (ENR), Norfloxacin (NOR), and Ofloxacin (OFL) were higher than 50%, the trophic magnification factors (TMFs) values for those QNs were calculated from three different habitats. The TMFs for those QNs were ranged from 0.840 to 1.10. Thereinto, ENR and NOR were appeared trophic magnification, while FLU and OFL were appeared trophic dilution in the food web of Baiyangdian Lake. Although the TMFs values of QNs were not showed significantly difference among three habitats, the TMFs values of those QNs showed significantly difference between the foodweb with macrophyte species and without macrophyte species. Except FLU, the other TMFs values of these QNs without macrophyte species (in the range of 0.700–1.01) were lower than the TMFs for QNs with macrophyte species. Finally, the results of human health risk for QNs suggested that consumption of fish from Baiyangdian Lake with a considerable risk, thus more standard and residue limits of QNs should be set to decrease the human health risk around this region. Capsule abstractThe spatial variation of bioaccumulation, trophic transfer, and human health risk for 12 QNs has been studied in the benthic foodweb from a macrophyte-dominated shallow lake.

A retrospective analysis of infection and antimicrobial susceptibility of genital mycoplasma in Changsha from 2010 to 2017

Objective To study the prevalence and antimicrobial susceptibility of Ureaplasma urealyticum (Uu) and Mycoplasma hominis (Mh) in Changsha, and provide laboratory evidence for clinical drug use. Methods A retrospective study was conducted to analyze 53 006 specimens of suspected genital mycoplasma infection in Xiangya Second Hospital of Changsha District and Hunan Wangwang Hospital from 2010 to 2017, and to analyze the infection rate and drug resistance rate of Uu and Mh. Results From 2010 to 2017, a total of 53 006 specimens were detected, where there were 16 830 cases of Uu infection, the infection rate was 31.75%; 2 471 cases of Mh infection, the infection rate was 4.66%; and 1 071 cases of Uu and Mh mixed infection, the infection rate was 2.02%. Male Uu infection rate was 19.48%(5 989/30 749), which was lower than the female infection rate 48.71%(10 841/22 257) (χ2=5 091, P<0.001); male Mh infection rate was 3.16%(973/30 749), lower than female infection rate 6.73%(1 498/22 257) (χ2=369,P<0.001). The population of genital mycoplasma infection is concentrated between 20 and 40 years old, accounting for 71.76% (12 077/16 830). The drug resistance rates of Uu and Mh to doxycycline and minocycline were less than 2%, while the drug resistance rate to quinolones was higher; The resistance rate of Uu to macrolide antibiotics such as erythromycin, josamycin and clarithromycin were less than 2%, while the resistance rate to azithromycin, erythromycin and roxithromycin were higher, 29.74%(5 006/16 830) and 53.74%(9 045/16 830), respectively, and the resistance rate of Mh to macrolide antibiotics (except josamycin) was higher than 90%.Between 2010 and 2017, a gradually increasing resistance of ureaplasmas to azithromycin, from 3.81% (46/1 206) in 2010 to 53.15% (1 503/2 828) in 2017, and decreasing resistance to gatifloxacin and thiamphenicol were observed, from 76.78% (926/1 206) and 60.28% (727/1 206) in 2010 decreased to 34.23% (968/2 828) and 37.87% (1 071/2 828) in 2017, respectively. The resistance rate of Mh to gatifloxacin and thiamphenicol were decreased, from 68.93% (122/177) and 41.81% (74/177) in 2010 to 53.54% (159/297) and 21.21% (63/297) in 2017, respectively. Conclusions Doxycycline, minocyclinum and josamycin are good treatment options for genital mycoplasma in Changsha. The resistance rate of Uu to azithromycin is increasing, suggesting that the abuse of azithromycin is present in Changsha, and indicating that better management of antibiotics is necessary. Key words: Reproductive tract infections; Mycoplasma infections; Mycoplasma hominis; Ureaplasma urealyticum; Drug resistance, bacterial

Quinolones antibiotics in the Baiyangdian Lake, China: Occurrence, distribution, predicted no-effect concentrations (PNECs) and ecological risks by three methods

The occurrence, distribution, and ecological risk of 10 quinolones (QNs) were investigated in the water and sediment samples from Baiyangdian Lake, China. The field samplings were conducted in April (dry season) and August (wet season) 2018, the results showed that QNs was extensively distributed in the Baiyangdian Lake. For the occurrence, Flumequine (FLU) and Ofloxacin (OFL) were the most detected QNs in Baiyangdian Lake. For the temporal variation, the sum concentration of QNs in water and sediment were ranged from 153 ng/L to 3093 ng/L and from 40.1 ng/g to 1475 ng/g in April, while ranged from 3.83 ng/L to 769 ng/L and from 20.3 ng/g to 373 ng/g in August. For the spatial variation, all of QNs exhibited significance difference in concentration at different sampling areas. Furthermore, PNEC plays an important role in ecological risk assessment, thus the PNECs of FLU and OFL were derived by assessment factors (AF), species sensitivity distribution (SSD), and AQUATOX model methods. The results showed that: PNECAFs, PNECSSDs, and PNECAQUATOXs were 18.7 μg/L, 196 μg/L, and 128 μg/L for FLU, respectively; and were 0.021 μg/L, 4.40 μg/L, and 3.00 μg/L for OFL, respectively. The PNECs for FLU and OFL derived by three approaches showed the rank of: PNECSSDs > PNECAQUATOXs > PNECAFs; while the risk quotients (RQs) followed the other rank of: RQSSDs < RQAQUATOXs < RQAFs. The results was indicated that the indirect ecological effects plays an important role in the derived PNECs for QNs, without considering the indirect ecological effects in natural ecosystem can lead to under-protective or over-protective PNECs (RQs) for chemicals. Therefore, AQUATOX model can be applied in deriving PNECs during the ecological risk assessment.

Modulatory Effects of Vitamin C on Enrofloxacin Induced Chromosome Damage and AgNOR Counts in Chick Bone Marrow Nuclei

Quinolones are broad spectrum antibiotics and are widely used in veterinary practice. But because of continuous improvement in their bactericidal and metabolic properties, it resulted in an increased amount of genotoxicity among animals. Vitamin C is a well-known antioxidant and a free radical scavenger and protects the cell from endogenous oxidative DNA damage. The aim of the study was to find the modulatory effect of Vitamin C against the enrofloxacin induced chromosomal aberrations and nuclear damage. The toxicity includes a significant decrease in mitotic index and increases in the number of chromosomal aberrations like break, deletion, centromeric attenuation, centric fusion and AgNOR counts in chicken bone marrow nuclei. The combined administration of enrofloxacin and Vitamin C resulted has markedly increased the mitotic index and reduced the chromosomal aberrations and AgNOR counts in the bone marrow cells.

Highly Integrated Microfluidic Chip Coupled to Mass Spectrometry for Online Analysis of Residual Quinolones in Milk.

In this work, a highly integrated microfluidic chip with multifunction coupled to mass spectrometry (MS) was developed for online analysis of seven different regulated quinolones (QNs) in milk samples. Procedures of sample extraction, immunoaffinity enrichment, magnetic separation, and online elution were performed simultaneously on the specifically designed device. Based on the specificity of antibodies, direct (electrospray ionization) ESI-MS at full scan mode without liquid chromatography (LC) separation and further tandem mass spectrometry (MS/MS) analysis was developed for the identification of target QNs. One single isotope internal standard (IS) method was presented for quantitative analysis of seven QNs. Upon targeted online extraction and enrichment by antibody conjugated magnetic beads, seven QNs were quantitatively determined by the IS method with the linear range of 0.2/0.5-10 ng/mL (R2 > 0.991). The limits of detection (LODs) for the seven QNs were in the range of 0.047-0.490 ng/mL. This system permits automated on-chip immunoaffinity enrichment and accurate MS detection without additional off-line cleanup procedures.