Quinolone Research Articles

Occurrence of pharmaceuticals and personal care products, and their associated environmental risks in a large shallow lake in north China.

Eighteen selected pharmaceuticals and personal care products (PPCPs), consisting of five non-antibiotic pharmaceuticals (N-APs), four sulfonamides (SAs), four tetracyclines (TCs), four macrolides (MCs), and one quinolone (QN) were detected in water, pore water, and sediment samples from Baiyangdian Lake, China. A total of 31 water samples and 29 sediment samples were collected in March 2017. Caffeine was detected with 100% frequency in surface water, pore water, and sediment samples. Carbamazepine was detected with 100% frequency in surface water and sediment samples. Five N-APs were prominent, with mean concentrations of 4.90-266.24ng/l in surface water and 5.07-14.73μg/kg in sediment samples. Four MCs were prominent, with mean concentrations of 0.97-29.92ng/l in pore water samples. The total concentrations of the different classes of PPCPs followed the order: N-APs (53.26%)>MCs (25.39)>SAs (10.06%)>TCs (7.64%)>QNs (3.64%) in surface water; N-APs (42.70%)>MCs (25.43%)>TCs (14.69%)>SAs (13.90%)>QNs (3.24%) in sediment samples, and MCs (42.12%)>N-APs (34.80%)>SAs (11.71%)>TCs (7.48%)>QNs (3.88%) in pore water samples. The geographical differences of PPCP concentrations were largely due to anthropogenic activities. Sewage discharged from Baoding City and human activities around Baiyangdian Lake were the main sources of PPCPs in the lake. An environmental risk assessment for the upper quartile concentration was undertaken using calculated risk quotients and indicated a low or medium-high risk from 18 PPCPs in Baiyangdian Lake and its five upstream rivers.

Composition and Distribution of Antibiotics in Soils with Different Land Use Types in a Typical Peri-urban Area of the Yangtze River Delta

Antibiotics have been widely used for agriculture, aquaculture, and livestock, as well as for human disease treatment, in recent decades. However, antibiotics cannot be completely absorbed, and most of them are excreted through urine and feces. A substantial part of the antibiotics enter soils through fertilization and irrigation. Antibiotics persist in the soil environment and threaten human and ecological security. Identifying the composition, distribution, and factors affecting antibiotics in soils with different land use types can help in understanding the spatial distribution and migration processes of antibiotics. In this study, a typical peri-urban catchment located in the Yangtze River delta was selected as the study area, and 82 sampling sites were selected based on land use and topographical features. Soil samples were collected at depths of 0-40 cm at each sampling site. The types and quantity of antibiotics in each soil sample were identified and analyzed by using HPLC-MS/MS in the laboratory. The composition and concentration of antibiotics in different soil layers and the land use types were compared, and the factors affecting the spatial distribution of soil antibiotics were analyzed. Results from this study showed that the total concentration of antibiotic compounds (total) ranged from 0.05 μg·kg-1 to 395.55 μg·kg-1 in the study area, and a significant spatial distribution of antibiotics was found between different land use types. The total in cropland ranged from 0.35 μg·kg-1 to 395.55 μg·kg-1, and tetracyclines (TCs) were the dominant antibiotics (81.45%). The total in forestland ranged from 0.07 μg·kg-1 to 3.65 μg·kg-1, with values significantly lower than those in cropland (P<0.05). The total in orchard soil were significantly lower than in cropland (P<0.05), and no significant differences in antibiotics were found between orchards and forestland (P>0.05). The analysis of the composition and quantity of antibiotics in the soils showed that tetracyclines (TCs) and quinolones (QNs) were the dominant antibiotic types in orchards (TCs:67.63%, QNs:29.55%) and forestland (TCs:13.25%, QNs:70.04%). The indices, including distance to town, distance to road, elevation, and C/N value in soils, were selected to explore the influence of human activity on soil antibiotic concentration. Results of the correlation analysis showed that the concentration of soil antibiotics decreased with increasing values of the four indices. This indicated that the concentrations of soil antibiotics in peri-urban areas were dominantly affected by land use and its spatial distribution, and the concentrations increased with the intensity of human activities. Results of this study can provide scientific guidance for soil management and soil security.

Profile and Antibiotic Resistance Genes of Escherichia c oli Strains Isolated from Ready-to-Eat Raw Mixed Vegetables Salads in Collective Catering in Abidjan, Côte D’Ivoire

In recent years many cases of food poisoning due to the consumption of vegetable salads contaminated with antibiotic-resistant strains of E. coli have been reported. The objective of the study was to detect the profile and the genetic factors of antibiotic resistance of Escherichia coli, isolated from ready-to-eat raw mixed vegetable salads, in catering. A total of 218 E. coli strains isolated from salads were confirmed by identification of iudA gene. Antibiotic resistance profile was determined by the agar diffusion method and by the detection of resistance genetic supports. Prevalence of E. coli resistant to antibiotics in vegetable salads was 70.2% with 28.4% of multi-resistant. Antibiotic resistance particularly concerned tetracycline (52.3%), streptomycin (38.5%) and to a lesser extent, nalidixic acid (15.6%). The genes aaa [3] -IV, CIMT, QnrA, tetA, tetB, cmlA and cat1 respectively conferring resistance to gentamicin, ampicillin, quinolones, tetracycline and chloramphenicol were highlighted. The study reveals that the risk of contamination by strains of E. coli resistant to antibiotics exist and require healthy control measures.

Pathogenicity of Mycoplasma genitalium and treatment of its infection

Mycoplasma genitalium is an important sexually transmitted pathogen which infects the reproductive tract and rectum of males and females. It can cause local inflammation by adhering to epithelial cells and activating the host immune response. In recent years, with the wide spread of macrolide-resistant strains, the efficacy of early use of azithromycin for the treatment of Mycoplasma genitalium infection has been obviously decreased. Quinolones such as moxifloxacin can increase the cure rate of Mycoplasma genitalium infection. However, with the emergence of quinolones-resistant strains, treatment failure cases have been reported. More seriously, there have been reports on multidrug-resistant strains which are resistant to both macrolides and quinolones. Doxycycline and pristinamycin can also be used for the treatment of Mycoplasma genitalium infection, but there are some disadvantages of low bacterial clearance rate and multiple daily administration. Therefore, new drugs and better treatment approaches for Mycoplasma genitalium infection are needed. Key words: Mycoplasma genitalium; Microbiological phenomena; Therapeutic uses; Anti-bacterial agents; Drug resistance

Antimicrobial resistance and virulence gene profiling of Salmonella Agona isolated from patients with diarrhea

Objective To investigate the antimicrobial resistance, molecular phenotypes, virulence gene profiles of Salmonella Agona (S.Agona) isolated from patients with acute diarrhea, and to better understand its epidemic trend, prevention and treatment. Methods Clinical data and stool samples of patients with acute diarrhea during April to October in 2013 and 2014 from the Second Hospital of Tianjin Medical University were collected. Enrichment culture, biochemical identification and serotyping analysis were used to isolate and identify S. Agona strains. The isolated strains were further analyzed with antibiotics susceptibility test, pulsed field gel electrophoresis (PFGE), multiple locus sequence typing (MLST), Quinolone resistance determining region (QRDR). Plasmid-mediated quinolone resistance (PMQR) and β-lactamases genes (TEM, SHV, OXA, and CTX-M) were amplified by polymerase chain reaction (PCR) and sequencing. The representative genes carried by Salmonella pathogenicity islands (SPI) 1—6, 9—12 and virulence plasmids were amplified by PCR. And the clinical characteristics of S. Agona infection were analyzed. Results Among 119 non-repetitive (non-typhoidal salmonella, NTS) isolates during the two years, eight isolates (6.7%) of S. Agona were identified. The resistance rate of S. Agona strains to streptomycin was 100.0%, those to ampicillin and gentamicin were 62.5%, to levofloxacin, ciprofloxacin and nalicixic acid were 25.0%, to chloramphenicol, amoxillin/clavulanic acid and piperacillin tazobactam were 12.5%. The strains were susceptible to other drugs. All 8 isolates had the identical ST13 genotype. PFGE showed 5 clones, and 4 out of 5 isolates had the exact same patterns of PFGE and drug susceptibility. Two (fluoroquinolones, FQ) resistant strains carried gyrA mutation leading to amino acid substitutions at position 87 in GyrA, and no PMQR genes was detected, while one of which was sensitive to ciprofloxacin by K-B method. All five ampicillin-resistant isolates were positive for TEM-1b gene and one isolate of them was resistant to β-lactam/β-lactamase inhibitor complex. The representative genes carried by SPI 1—6, 9, 11, 12 (hilA, sseL, mgtC, siiE, sopB, pagN, bapA, pagC and sspH2) were 100.0% positive, while the genes carried by SPI10 (sefA) virulence plasmids (spvB, prot6E) were negative. Two patients with FQ resistant strains infection were clinically diagnosed with bacillary dysentery, and the remaining six cases with FQ susceptible strains infection were clinically diagnosed with acute gastroenteritis. Conclusions FQs-resistant and multi-drug resistant S. Agona isolates have emerged in clinical settings. These isolates carry a variety of virulence genes. Resistance to FQ of S. Agona may cause more severe illness. ST13 might be the dominant genotype of S. Agona in China, and we should try to prevent the infection outbreak of S. Agona. Key words: Salmonella Agona; Antimicrobial resistance; Multiple locus sequence typing; Pulsed field gel electrophoresis; Infection outbreak; Salmonella pathogenicity islands

Treatment of Chronic Q Fever: Clinical Efficacy and Toxicity of Antibiotic Regimens.

Evidence on the effectiveness of first-line treatment for chronic Q fever, tetracyclines (TET) plus hydroxychloroquine (HCQ), and potential alternatives is scarce. We performed a retrospective, observational cohort study to assess efficacy of treatment with TET plus quinolones (QNL), TET plus QNL plus HCQ, QNL monotherapy, or TET monotherapy compared to TET plus HCQ in chronic Q fever patients. We used a time-dependent Cox proportional hazards model to assess our primary (all-cause mortality) and secondary outcomes (first disease-related event and therapy failure). We assessed 322 chronic Q fever patients; 276 (86%) received antibiotics. Compared to TET plus HCQ (n = 254; 92%), treatment with TET plus QNL (n = 49; 17%), TET plus QNL plus HCQ (n = 29, 10%), QNL monotherapy (n = 93; 34%), or TET monotherapy (n = 54; 20%) were not associated with primary or secondary outcomes. QNL and TET monotherapies were frequently discontinued due to insufficient clinical response (n = 27, 29% and n = 32, 59%). TET plus HCQ, TET plus QNL, and TET plus QNL plus HCQ were most frequently discontinued due to side effects (n = 110, 43%; n = 13, 27%; and n = 12, 41%). Treatment of chronic Q fever with TET plus QNL appears to be a safe alternative for TET plus HCQ, for example, if TET plus HCQ cannot be tolerated due to side effects. Treatment with TET plus QNL plus HCQ was not superior to treatment with TET plus HCQ, although this may be caused by confounding by indication. Treatment with TET or QNL monotherapy should be avoided; switches due to subjective, insufficient clinical response were frequently observed.

Preliminary study on qualitative and quantitative detection of norfloxacin based on terahertz spectroscopy

Norfloxacin is a kind of quinolone bactericide which is widely used in food industry, livestock feed and medicine area. At present, how to develop a rapid, convenient and accurate technique for qualitative and quantitative detection of norfloxacin is still a challenge. In this study, Terahertz Time-domain Spectroscopy technology (THz-TDS) was used to explore qualitative and quantitative analysis of norfloxacin. Forty-five norfloxacin samples with different levels were prepared. The pure norfloxacin powder was mixed with polyethylene (PE) powder together and made into tablets by tablet-making machine. The minimum detection concentration was 10% and the maximum detection concentration evaluated in the paper was 90%. Then, terahertz (THz) spectra of each sample were measured on K15 THz-TDS equipment. The multiple linear regressions and the partial least squares regression algorithms were used to establish a model to make quantitative analysis. From the results, two typical fingerprint peaks of norfloxacin in terahertz band were observed at 0.944 THz and 1.206 THz, and the correlation coefficient and the root mean square error of the established model reached 0.9908 and 0.0481, respectively, which showed that the model performed well for the prediction. This preliminary study indicates that THz spectroscopy has great potential for future screening applications to detect the presence of norfloxacin residues in food, livestock feed and medicine industries. Keywords: Terahertz spectroscopy, norfloxacin, qualitative and quantitative detection, model, correlation coefficient DOI: 10.25165/j.ijabe.20171005.2962 Citation: Long Y, Li B. Preliminary study on qualitative and quantitative detection of norfloxacin based on terahertz spectroscopy. Int J Agric & Biol Eng, 2017; 10(5): 262–268.

Determination of eight quinolones in milk using immunoaffinity microextraction in a packed syringe and liquid chromatography with fluorescence detection.

We have established a new, highly selective, and sensitive method for the determination of eight quinolones (QNs) in milk: danofloxacin, enrofloxacin, orbifloxacin, norfloxacin, ofloxacin, lomefloxacin, fleroxacin, and ciprofloxacin. The method uses immunoaffinity microextraction in a packed syringe and liquid chromatography with fluorescence detection (IA-MEPS-LC-FLD). Traditionally, QN residues are determined by liquid-liquid extraction (LLE) and solid phase extraction (SPE) sample preparation techniques; however, these methods are time-consuming and require large quantities of organic solvents. We thus developed a novel immunoaffinity adsorbent combined with MEPS for QN residue analysis. The syringe was filled with 0.2g of microbeads bound with a QN monoclonal antibody using glutaraldehyde. The relevant parameters of the IA-MEPS method were optimized and discussed herein. Milk samples were extracted at a flow rate of 3.5mL/min, 600μL of methanol-and phosphate-buffered saline (9:1, v/v) was used for elution, and 200μL of mobile phase was used for reconstitution after the sample was dried with nitrogen. Then, the sample was detected by LC-FLD. For the eight QNs, the limit of detection ranged from 0.05 to 0.1ng/g, the limit of quantification ranged from 0.15 to 0.3ng/g, and the intra- and inter-day precision were 3.2%-14.6% and 9.1%-15.8%, respectively. The advantages of the IA-MEPS method includ simple operation, low cost and reduced organic solvent use. Moreover, the sample pretreatment is environmentally friendly because of the reduced solvent volume requirements.

Pathogen distribution, risk factors, and outcomes of nosocomial infection in very premature infants

To study the pathogen distribution and risk factors of nosocomial infection in very preterm infants, as well as the risk of adverse outcomes. A retrospective analysis was performed for the clinical data of 111 very preterm infants who were born between January and December, 2016 and had a gestational age of <32 weeks and a birth weight of <1 500 g. According to the presence or absence of nosocomial infection after 72 hours of hospitalization, the infants were divided into infection group and non-infection group. The infection group was analyzed in terms of pathogenic bacteria which caused infection and their drug sensitivity. A multivariate logistic regression analysis was used to investigate the potential risk factors and risk of adverse outcomes of nosocomial infection in very preterm infants. Gram-negative bacteria were the main pathogens for nosocomial infection in very preterm infants and accounted for 54%, among which Pseudomonas aeruginosa was the most common one; the following pathogens were fungi (41%), among which Candida albicans was the most common one. The drug sensitivity test showed that Gram-negative bacteria were highly resistant to β-lactam and carbapenems and highly sensitive to quinolones, while fungi had low sensitivity to itraconazole and high sensitivity to 5-fluorocytosine and amphotericin B. Early-onset sepsis, duration of peripherally inserted central catheter, steroid exposure, and duration of parenteral nutrition were risk factors for nosocomial infection in very preterm infants (P<0.05). Compared with the non-infection group, the infection group had significantly higher risks of pulmonary complications (P<0.05), as well as a significantly longer length of hospital stay and a significantly higher hospital cost (P<0.001). Nosocomial infection in very preterm infants is affected by various factors and may increase the risk of adverse outcomes. In clinical practice, reasonable preventive and treatment measures should be taken with reference to drug sensitivity, in order to improve the prognosis of very premature infants.

Evaluation of milk hygienic quality in milk processing plant: Parameters of the mammary gland's health and milking instruments’ hygiene

In the present research, a carrier mediated hollow fiber based liquid-phase microextraction approach (HF-LPME) prior to high performance liquid chromatography-diode array detection (HPLC-DAD) was developed for the simultaneous determination of the antibacterial residues of four tetracyclines (TCs) and five quinolones (QNs), which are commonly used as veterinary medicines. In order to obtain high extraction efficiency, the parameters affecting HF-LPME were optimized using a three-factor and three-level Box-Behnken design under response surface methodology. This method was validated according to the recommendations of the Food and Drug Administration (FDA), and, for the first time, successfully applied to a wide range of animal source food samples such as fish, milk, and honey as well as the liver and muscles of lamb and chicken. Analytical performance was determined in terms of linearity, intra- and inter-assay precision, detection and quantification limits, matrix effect, accuracy, and drug stability in real samples. Detection and quantitation limits for the different antibiotics ranged between 0.5–20 ng g−1 and 1.25–40 ng g−1, respectively. Intra and inter-day repeatability, expressed as the relative standard deviation, were in the ranges of 3.4–10.7% and 5.0–11.5%, respectively. The procedure allows good preconcentration factors of 175–700. The results of the validation process proved that the method is suitable for determining TCs and QNs residues in surveillance programs. Finally, the applicability of the proposed method was successfully confirmed by the extraction and determination of nine antibiotics in various animal source food samples. The importance of this methodology relies on the combination of HF-LPME/HPLC-DAD second-order data with multivariate curve resolution-alternative least squares (MCR-ALS) algorithm, which improves the resolution of some overlapped chromatograms and, hence, increases the accuracy and repeatability of drug determination.

Outpatient use of antibiotics in children in Slovenia

Background: Antibiotics are among the most common drugs prescribed in outpatient settings. It is estimated that up to 50 % are prescribed unnecessarily or inappropriately. To plan the actions for optimizing the use of antibiotics, we conducted a national antibiotic consumption study in children aged 0–18 years in the period between 2003 and 2015. Methods: In this national retrospective research we analyzed outpatient antibiotic consumption using ATC/DDD classification. The use of antibiotics was recorded in relation to the pattern of prescription, age, gender and health region. Results: The total consumption of antibiotics decreased by 35 % from 979 to 636 prescriptions per 1000 children/year (PTY) during the whole study period. Te use of all antibiotic classes decreased (except for quinolones and nitrofuran derivatives) by 12.5 %–81 %. In all those years we recorded the highest consumption in children aged 1 to 4 years (2184–1160 PTY). Amoxicillin was the most commonly prescribed antibiotic in children aged 0 to 4 years, penicillin V among 5 to 14 years and co-amoxiclav among adolescents aged 15 to 19 years. In health regions in the northeastern part of Slovenia much more antibiotics were prescribed than in other regions. In 2015, 65 % of prescriptions were prescribed by pediatricians and school medicine specialists, 16 % by physicians without specialization, 14 % by GPs/family doctors and 5 % by other specialists. Conclusions: Despite the decrease in outpatient antibiotic use in children and adolescents in Slovenia, the overall and especially broad-spectrum antibiotic consumption (amoxicillin with clavulanic acid, azithromycin and second/third generation cephalosporins) is still too high. It is necessary to strengthen activities to reduce prescribing, particularly for acute (upper) respiratory tract infections.

Prevalence of Plasmid-Mediated Quinolones Resistance among Klebsiella pneumoniae Strains Isolated from Hospitals in Borujerd, Iran

Prevalence of Plasmid-Mediated Quinolones Resistance among Klebsiella pneumoniae Strains Isolated from Hospitals in Borujerd, Iran

Pefloxacin as a surrogate marker for quinolone susceptibility in Salmonella enterica serovars Typhi & Paratyphi A in India.

Background & objectives:The emergence of resistance to fluoroquinolones in enteric fever despite the pathogen being susceptible by in vitro laboratory results, led to repeated changes in Clinical and Laboratory Standard Institute (CLSI) guidelines for this class of antibiotics to have specific and sensitive interpretative criteria. In 2015, CLSI added pefloxacin disk diffusion criteria as a surrogate marker for fluoroquinolone susceptibility. This study was carried out to evaluate the use of pefloxacin as a surrogate marker for ciprofloxacin, ofloxacin and levofloxacin susceptibility in clinical isolates of Salmonella Typhi and S. Paratyphi A.Methods:A total of 412 strains of S. Typhi and S. Paratyphi A were studied for pefloxacin disk diffusion test as a surrogate marker for susceptibility to ciprofloxacin, ofloxacin and levofloxacin as per CLSI and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. Molecular mechanisms of resistance to fluoroquinolones were also determined and correlated with pefloxacin susceptibility breakpoints.Results:Of the total 412 strains, 34 were susceptible to ciprofloxacin and 33 each to levofloxacin and ofloxacin using CLSI minimum inhibitory concentration (MIC) breakpoints. There was a positive correlation between MICs with correlation coefficients 0.917, 0.896 and 0.958 for the association between ciprofloxacin and ofloxacin, ciprofloxacin and levofloxacin and ofloxacin and levofloxacin, respectively (P <0.001). The sensitivity, specificity and positive predictive value of pefloxacin as a surrogate marker using ciprofloxacin MIC as a gold standard were 100, 99.5 and 94.4 per cent, while 100, 99.2 and 91.7 per cent taking ofloxacin and levofloxacin MIC as gold standard. Mutations in target genes correlated with the pefloxacin susceptibility results.Interpretation & conclusions:Our results showed that pefloxacin served as a good surrogate marker for the detection of susceptibility to ciprofloxacin, ofloxacin and levofloxacin in S. Typhi and S. Paratyphi A. Further studies are required to confirm these findings.

Prevalence of plasmid-mediated quinolone resistance genes in Klebsiella pneumoniae strains in pediatrics in China

Objective To investigate the prevalence of plasmid-mediated quinolone resistance (PMQR) genes among clinical isolates of Klebsiella pneumoniae (K.pneumoniae) in pediatrics. Methods A total of 131 non-duplicate clinical isolates of K. pneumoniae were collected in the Affiliated Children′s Hospital of Capital Institute of Pediatrics from 2010 to 2012. PMQR genes [qnrA, qnrB, qnrS, aac(6′)-Ⅰb-cr and qepA], mutations in the quinolone resistance-determining region (QRDR) and extended spectrum β-lactamases (ESBLs) genes in those strains were analyzed by PCR. Minimum inhibitory concentrations (MIC) of different antibiotics against those K. pneumoniae strains were determined by broth microdilution method and E-test according to the guidelines issued by the Clinical and Laboratory Standards Institute (CLSI). Transferability of the PMQR genes was examined by conjugation test with the sodiumazide-resistant Escherichia coli J53. Results Among the 131 isolates, 9.92% were resistant to quinolone and 30.5% were positive for PMQR genes, including 6.87% harboring qnrB gene, 22.9% harboring qnrS gene and 4.58% harboring aac(6′)-Ⅰb-cr gene. Neither qnrA-positive nor qepA-positive strain was detected. Among these PMQR genes-positive isolates, 90% were ESBLs-producing strains and two presented mutations in gyrA and parC genes. Conjugation test showed that these PMQR genes could be transferred horizontally and the ciprofloxacin resistance increased 2 to 32 folds in transconjugants. Conclusion This study indicates that the PMQR gene-carrying rate is high in K. pneumoniae strains isolated in paediatrics in China. Most of the PMQR gene-positive strains are also ESBLs-producing strains. The PMQR genes could be transferred horizontally in bacteria. Key words: Klebsiella pneumoniae; PMQR; ESBLs

PCR-RFLP-Based Detection of Mutations in the Chromosomal Fluoroquinolone Targets g yr A and p ar C Genes of Acinetobacter b aumanii Clinical Isolates from a Tertiary Hospital in Cairo, Egypt

Background and Aim: Acinetobacter baumannii is one of the most antimicrobial resistant nosocomial pathogens encountered clinically worldwide. The emergence of fluoroquinolone resistance among A. baumannii isolates is currently of concern. This study aimed to investigate the antimicrobial susceptibility patterns among 49 clinical isolates of A baumannii collected from a tertiary care hospital in Egypt. These isolates were analysed for the mechanism of fluoroquinolone resistance based on the presence of mutations in the quinolone resistance-determining regions (QRDRs) of the chromosomal quinolone resistance determinants gyrA and parC genes. Methods: A. baumannii isolates were identified using conventional biochemical testing, VITEK 2 automated system and polymerase chain reaction (PCR) assay targeting the intrinsic blaOXA-51-like gene of A. baumannii species. Antimicrobial susceptibility to different antimicrobial agents was tested using agar disk diffusion method and the minimum inhibitory concentration (MIC) of ciprofloxacin was determined using E-test (bioMerieux, France) on Mueller-Hinton agar medium following the Clinical and Laboratory Standards Institute guidelines. The QRDRs of the gyrA and parC genes in A. baumannii isolates were amplified by PCR using specific primers. Mutations in theses QRDRs were detected by HinfI restriction fragment length polymorphism (RFLP) of PCR products and sequencing. Results: The blaOXA-51-like gene was detected in all isolates confirming identification as A. baumannii. Antimicrobial susceptibility study showed that all isolates (100 %) were MDR. They were 100 % resistant to the tested fluoroquinolones, ciprofloxacin and levofloxacin. The MIC of ciprofloxacin ranged from 4 to ≥ 32 μg/mL. All A. baumannii isolates (100 %) were found to harbour gyrA and parC genes. HinfI restriction analysis showed a detectable mutation in QRDRs at position Ser-83 of gyrA gene and Ser-80 of parC gene. There was single mutation in either gyrA or parC in 11 isolates showed ciprofloxacin MIC of < 32 μg/mL, while 38 isolates with MIC of ≥ 32 μg/mL had double mutations in QRDRs of both genes. Conclusions: Resistance of A. baumannii isolates to fluoroquinolones in Egypt is alarming as all MDR A. baumannii isolates in the current study were mostly highly resistant to ciprofloxacin with MIC ≥ 32 μg/mL, limiting the remaining therapeutic options and a public health policy on appropriate prescribing and thus the rational use of antimicrobial agents is required. Double mutation with substitutions at positions Ser-83 and Ser-80 of gyrA and parC genes, respectively, could lead to high‐level ciprofloxacin resistant phenotype than a single mutation in one of them. Further extensive studies including a larger number of isolates from different geographic areas in Egypt and investigating other fluoroquinolone resistance mechanisms are warranted.

The Epsilon Subunit of DNA Polymerase III in the Bacterial Response to Quinolones

Quinolones are widely prescribed, broad‐spectrum antibacterial drugs. Despite their widespread use, the molecular mechanisms of quinolone cytotoxicity are not clearly understood. Quinolones target topoisomerases, preventing the resealing of otherwise transient DNA breaks. Poisoned topoisomerase, or stabilized cleavage complexes, are not sufficient for cell death. The goal of this study is to determine how stabilized cleavage complexes are converted into irreversible double strand DNA breaks (DSBs) that accumulate and drive quinolone cytotoxicity.Previous studies identified an unexpected connection between dnaQ and quinolone‐induced DNA damage in Escherichia coli. The ɛ subunit of DNA polymerase III, encoded by dnaQ, is an exonuclease providing the 3′ ‐&gt; 5′ proofreading activity of the core. The absence of ɛ causes higher mutation rates, slow growth, constitutive SOS, and a defective SOS response following quinolone treatment. We found that these phenotypes are separable, which implies that ɛ has multiple, separable roles, aside from proofreading.We explore the role of ɛ‐β interaction in quinolone‐induced DSB generation. Using two different types of cell lysis in conjunction with pulsed‐field gel electrophoresis, we distinguished between latent breaks at the cleavage complex and overt chromosomal breaks due to additional processing. We provide evidence that supports the replication run‐off model of DSB generation, whereby a stronger ɛ‐β interaction causes the replicase to physically interact with stabilized cleavage complexes rather than stalling or disassembling.Support or Funding InformationGettysburg College Research &amp; Professional Development Grant &amp; Howard Hughes Medical Institute ‐ Cross‐Disciplinary Sciences Institute at Gettysburg College

Development perspectives of silver complexes with antibacterial quinolones: Successful or not?

Antibacterial quinolones (QNs) are synthetic compounds with excellent complexation properties due to 4-oxo-1,4-dihydroquinolone structure with a 7-heterocycle containing nitrogen atoms. The metal complexes of these compounds had led to increased bacterial activity or other biological effects in comparison with the free ligand. Silver complexes with quinolone derivatives can offer a promising perspective through potential antibacterial, antiseptic, anti-inflammatory, and cytotoxic effects. In this review the obtaining methods of silver complexes with QNs are compared and discussed; in order to elucidate the chemical structure of reported silver complexes all reported information are reviewed and also the studied biological effects are highlighted and discussed.

Occurrence and elimination of antibiotics in three sewage treatment plants with different treatment technologies in Urumqi and Shihezi, Xinjiang.

Fourteen antibiotics, including five quinolones (QNs), five sulfonamides (SAs), and four tetracyclines (TCs), were selected to investigate their occurrence and elimination in three sewage treatment plants (STPs) by employing different treatment technologies in Urumqi (two STPs) and Shihezi (one STP), China. The STP in Shihezi was chosen as representative to investigate the distribution of antibiotics in a sludge-sewage system. Results showed that the concentrations of most detected antibiotics ranged from tens to hundreds of nanograms per liter in influent samples and under 100 ng L-1 in effluent samples. QNs and TCs were dominant species with concentrations of 2.33 mg kg-1 to 3.34 mg kg-1 and 0.36 mg kg-1 to 0.47 mg kg-1 in sludge samples, respectively. The elimination rates of target antibiotics by various STPs ranged from 17% to 100%. The STP with anaerobic/anoxic/aerobic and membrane bio-reactor technology removed antibiotics more efficiently than those with anaerobic/anoxic/oxic and oxidation ditch technology. The elimination capacities of treatment units from the three STPs were also investigated. SAs were mainly degraded in biological treatment units; conversely, QNs and TCs were significantly eliminated in sedimentary treatment units. Ozonation effectively removed remaining antibiotics but not UV and chlorination disinfection in this study.

19 Delivery of 1,2-dihydroquinolines via transferrin-targeted liposomes

Objectives Quinolines have been shown to have anticancer activities. This study investigates delivery of a novel quinolone using liposomes targeted to cancer cells. Methods A 1, 2-dihydroquinoline was loaded into transferrin-targeted liposomes. Lipids (6.0 μmol), HSPC, cholesterol and PEG-DSPE in the ratio 63:36:1, and 0.5 μmol 1, 2-dihydroquinoline were dissolved in ethanol. An ethanol injection method was used to prepare transferrin-targeted liposomes. Mean particle size and ζ potential measurements, cytotoxicity assay, flow cytometry and confocal microscopy were performed. Results The mean particle size of transferrin liposomes was 124 ± 2.7 nm. The ζ potential was −6 ± 1.2 mV. Transferrin-targeted liposomes showed high cytotoxicity for tumour cells. In competitive binding assays, the uptake from transferrin-targeted liposomes was inhibited 78% by 10 nM holo human transferrin. Flow cytometry and confocal microscopy analyses indicated that association of transferrin-targeted liposomes to tumour cells was much greater than that of non-targeted liposomes. Conclusions We have identified a 1, 2-dihydroquinoline as a potential anticancer agent. Furthermore, this compound can be efficiently loaded into transferrin-targeted liposomes for targeted delivery to tumour cells. These data suggest that transferrin-targeted liposomes carrying 1, 2-dihydroquinoline are a potential anticancer agent for clinical application. Acknowledgements This research was supported by Jilin Province Science and Technology Development Program (Grant No. 20140311072YY) and Jilin Province Science and Technology Development Program (Grant No. 20150520141JH).

Antibiotics in WWTP discharge into the Chaobai River, Beijing

Abstract22 representative antibiotics, including 8 quinolones (QNs), 9 sulfonamides (SAs), and 5 macrolides (MCs) were selected to investigate their occurrence and removal efficiencies in a Wastewater Treatment Plant (WWTP) and their distribution in the receiving water of the Chaobai River in Beijing, China. Water quality monitoring was performed in an integrated way at different selected points in the WWTP to explore the potential mechanism of antibiotics removal during wastewater treatment. Water quality of the Chaobai River was also analyzed to examine environmental distribution in a river ecosystem. The results showed that within all the 22 compounds examined, 10 antibiotics were quantified in wastewater influent, 10 in effluent, and 7 in river. Sulfadiazine (SDZ, 396 ng/L) and Sulfamethazine (SMZ, 382 ng/L) were the dominating antibiotics in the influent. Both the conventional treatment and advanced Biological Aerated Filter (BAF) system was important for the removal of antibiotics from the wastewater. And the concentrations of selected antibiotics were ranged from 0-41.8 ng/L in the effluent-receiving river. Despite the fact that the concentrations were reduced more than 50% compared to effluent concentrations, WWTP discharge was still regarded as a dominant point-source input of antibiotics into the Chaobai River.