Common Fluoroquinolone Research Articles

Pharmacokinetic model of human exposure to ciprofloxacin through consumption of fish

Fluoroquinolones are broad-spectrum antibiotics that accumulate in the environment. To assess human exposure through the food chain, we developed a pharmacokinetic model of fluoroquinolone accumulation in fish and a human pharmacokinetic model to predict gastrointestinal concentrations of ciprofloxacin, a common fluoroquinolone, following consumption of fish. At 70 ng/L ciprofloxacin, the average in North American surface waters, the fish steady-state concentration was calculated to be 7.5 × 10−6 µg/g. Upon human consumption of the FDA-recommended portion of 113 g of fish containing this ciprofloxacin level, the predicted human intestinal concentration was 2 × 10−6 µg/mL. At 4 × 106 ng/L (4 µg/mL) ciprofloxacin, the highest recorded environmental measurement, these numbers were 0.42 µg/g in fish and 0.1 µg/mL in the human intestine. Thus, based on the ciprofloxacin MIC for E. coli of 0.13 µg/mL, background environmental ciprofloxacin levels are unlikely to be problematic, but environmental pollution can result in high intestinal levels that may cause gut dysbiosis and antibiotic resistance.

Unveil the mechanism of photosensitized fluoroquinolones enhancing chlortetracycline photodegradation under simulated sunlight: Batch experiments and DFT calculation

Fluoroquinolones (FQs), as the most commonly used antibiotics, are ubiquitous in the aquatic environment. The FQs' self-sensitization process could generate reactive oxygen species (ROS), which could react with other coexisting organic pollutants, impacting their transformation behaviors. However, the FQs’ influences and mechanisms on the photochemical transformation of coexisting antibiotics are not yet revealed. In this study, we found ofloxacin (OFL) and norfloxacin (NOR), the two common FQs, can obviously accelerate chlortetracycline (CTC) photodegradation. In the presence of OFL and NOR (i.e., 10 μM), CTC photodegradation rate constants increased by 181.1% and 82.9%, respectively. With the help of electron paramagnetic resonance (EPR) and quenching experiments, this enhancement was attributed to aromatic ketone structure in FQs, which absorbed photons to generate ROS (i.e., 3OFL*, 3NOR*,1O2, and •OH). Notably, 3OFL* or 3NOR* was dominantly contributed to the enhanced CTC photodegradation, with the contribution ratios of 79.9% and 77.3% in CTC indirect photodegradation, respectively. Compared to CTC direct photodegradation, some new photodegradation products were detected in FQs solution, suggesting that 3OFL* or 3NOR* may oxide CTC through electron transfer. Moreover, the higher triple-excited state energy of OFL and NOR over DFT calculation implied that energy transfer from 3OFL* or 3NOR* to CTC was also theoretically feasible. Therefore, the presence of FQs could significantly accelerate the photodegradation of coexisting antibiotics mainly via electron or energy transfer of 3FQs*. The present study provided a new insight for accurately evaluating environmental behaviors and risks when multiple antibiotics coexist.

Molecular epidemiology of antibiotic-resistant Escherichia coli among clinical samples isolated in Azerbaijan, Iran.

The immediate emergence of resistant bacteria poses an increasingly growing problem to human society and the increasing prevalence of antibiotic resistance in Escherichia coli strains is one of the most important health problems. This study aimed to review the molecular epidemiology of drug resistance among clinical isolates of E. coli in north-west portion of Iran Azerbaijan. A complete of 219 clinical isolates of E. coli had been collected from the various clinical samples. The disk diffusion and agar dilution assays were used to determine antimicrobial susceptibility. The presence of antibiotics resistance genes was carried out by the PCR method. The highest susceptibility was shown to imipenem (3%) and fosfomycin (3%), and the most antibiotic resistance was presented to ampicillin (99%). The highest frequent ESBL gene among isolates was bla CTXM-15 in 70% followed by blaCMY-2 in 67%, and blaTEM-1 in 46%. The most common fluoroquinolone (FQ) resistance genes were oqxB (34%), followed by oqxA (25%), and qnrB (18%). The frequency of tetracycline resistance genes (tetA, tetB, tetC, and tetD) were detected in 24.8%, 31.6%, 1.8%, and 4.2%, respectively. The highest frequent genes to fosfomycin were fosA 10%, fosA3 30%, fosC 40%, and fosX 20%. The dominant founded aminoglycosides resistant genes were armA (12.96%) and npmA (4.93%). The prevalence of antibiotics resistance in the tested E. coli isolates was high in Azerbaijan, Iran and these findings showed that E. coli is one of the major drug-resistant pathogens.

Development of a rapid detection method for enrofloxacin in food

ABSTRACT Develop the ic-ELISA rapid detection method of Enrofloxacin (ENR). Corresponding antibodies are obtained by animal immunity to identify their titer and specificity. The optimal coating time was obtained by indirect competition ELISA, and the antigen coating time, suitable coating concentration, primary antibody dilution factor, blocking solution blocking time, primary antibody reaction time and secondary antibody reaction time were optimized, and the specificity and accuracy of the method were evaluated. The ic-ELISA rapid detection method of ENR, IC50 was 9.13 ng/mL, and the linear detection range (IC20-IC80) was 4.16–20.03 ng/mL. The LOD limit is 2.11 ng/mL. The cross-reactivity rate of 9 fluoroquinolones was above 10%, and the average recovery rate was above 80%. The reason why the heterologous coating is more sensitive may be due to the fact that the piperazine group of ofloxacin is one less carbon atom than enrofloxacin, and ofloxacin is connected to the main ring by N and O hybridization, while enrofloxacin is connected to the main ring through a ternary ring, these two reasons may cause the charge density of extracyclic oxygen at the ofloxacin binding site to be higher than that of enrofloxacin, and the binding ability to antibodies is stronger. Therefore, when heterologous coating, the competitive inhibition rate against enrofloxacin is higher and the effect is better. The conclusion obtained through this experiment is that the detection method has strong broad spectrum and good sensitivity, and can quickly detect the total amount of enrofloxacin and its seven common fluoroquinolones in fish and eggs.

Adsorption of Fluoroquinolone Antibiotics from Water and Wastewater by Colemanite.

Pharmaceutical residues in water and wastewater have become a worldwide problem with environmental and public health consequences. Antibiotics are of special importance because of the emergence of antibiotic-resistant genes. This study evaluates the adsorptive removal of four common fluoroquinolone antibiotics by using natural colemanite as an alternative adsorbent for the first time. Batch adsorption experiments were conducted for the mixture of fluoroquinolones as well as for individual compounds during the isotherm studies. Adsorption kinetic results indicated that the process followed the pseudo-second-order (PSO) model, while the Langmuir model described the sorption isotherms. The effects of pH and temperature on adsorption performance were determined, and the results indicated that the adsorption was endothermic and spontaneous, with increasing randomness at the solid-liquid interface. The effects of real water and wastewater matrices were tested by using tap water, surface water, and wastewater samples. Reusability experiments based on five adsorption-desorption cycles indicated that the adsorption performance was mostly retained after five cycles. The adsorption mechanism was elucidated based the material characterization before and after adsorption. The results indicate that colemanite can be used as an effective and reusable adsorbent for fluoroquinolone antibiotics as well as for other pollutants with similar physicochemical properties.

Occurrence and Risk Assessment of Fluoroquinolone Residues in Chicken and Pork in China.

Antibiotics, especially fluoroquinolones, have been exhaustively used in animal husbandry. However, very limited information on the occurrence and exposure assessment of fluoroquinolone residues in chicken and pork in China is available to date. Thus, a total of 1754 chicken samples and 1712 pork samples were collected from 25 provinces in China and tested by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS) for residual determination of six common fluoroquinolones. The results revealed that the detection frequencies of fluoroquinolone residues were 3.99% and 1.69% in chicken and pork samples. The overall violation frequencies were 0.68% and 0.41% for chicken and pork. Enrofloxacin and its metabolite ciprofloxacin were found to be the most predominant fluoroquinolones. The occurrence of these antibiotics in different sampling regions and market types was analyzed. The %ADI values of enrofloxacin and ciprofloxacin were far less than 100, indicating the health risk associated with the exposure to these aforementioned fluoroquinolone residues via chicken and pork for Chinese children, adolescents, and adults was acceptable. The results provided useful references for Chinese consumers, and helped to appropriately use these antibiotics in poultry and livestock industry.

Development of a colloidal gold immunochromatographic strip for the rapid detection of pefloxacin in grass carp with a novel pretreatment method

A rapid colloidal gold immunochromatography assay (GICA) for the detection of pefloxacin (PEF) was established and optimized. The anti-PEF monoclonal antibody (mAb) was used to target PEF as a colloidal gold-mAb conjugate. The mAb belonged to the IgG2b subtype, lambda light chain, the affinity constant (Ka) was 5.21 × 109 L·mol−1, and its half maximal inhibitory concentration (IC50) was 0.23 ng·mL−1. No obvious cross-reactivity (CR) was observed with other common fluoroquinolone antibiotics, including ciprofloxacin (CIP), norfloxacin (NOR), lomefloxacin (LOM) and ofloxacin (OFL). The visual limit of detection (vLOD) of the optimized GICA was 2 ng·g−1 under the conventional pretreatment method, and the assay was completed in 15 min. Liquid chromatography tandem-mass spectrometry (LC–MS/MS) was employed to confirm the performance of the strip. In addition, a novel pretreatment was established and compared with conventional pretreatment. Without the removal of organic solvents, the novel pretreatment method reduced the sample pretreatment time (more than 10 min). The vLOD of the optimized GICA was also 2 ng·g−1 when applying the novel pretreatment method. In conclusion, the proposed PEF-GICA could detect samples containing PEF rapidly and accurately, and the novel pretreatment method saved the time of sample pretreatment and improved the efficiency of detection.

Solvent-Mediated Proton-Transfer Catalysis of the Gas-Phase Isomerization of Ciprofloxacin Protomers.

Understanding how neutral molecules become protonated during positive-ion electrospray ionization (ESI) mass spectrometry is critically important to ensure analytes can be efficiently ionized, detected, and unambiguously identified. The ESI solvent is one of several parameters that can alter the dominant site of protonation in polyfunctional molecules and thus, in turn, can significantly change the collision-induced dissociation (CID) mass spectra relied upon for compound identification. Ciprofloxacin─a common fluoroquinolone antibiotic─is one such example whereby positive-ion ESI can result in gas-phase [M + H]+ ions protonated at either the keto-oxygen or the piperazine-nitrogen. Here, we demonstrate that these protonation isomers (or protomers) of ciprofloxacin can be resolved by differential ion mobility spectrometry and give rise to distinctive CID mass spectra following both charge-directed and charge-remote mechanisms. Interaction of mobility-selected protomers with methanol vapor (added via the throttle gas supply) was found to irreversibly convert the piperazine N-protomer to the keto-O-protomer. This methanol-mediated proton-transport catalysis is driven by the overall exothermicity of the reaction, which is computed to favor the O-protomer by 93 kJ mol-1 (in the gas phase). Conversely, gas phase interactions of mobility-selected ions with acetonitrile vapor selectively depletes the N-protomer ion signal as formation of stable [M + H + CH3CN]+ cluster ions skews the apparent protomer population ratio, as the O-protomer is unaffected. These findings provide a mechanistic basis for tuning protomer populations to ensure faithful characterization of multifunctional molecules by tandem mass spectrometry.

Ciprofloxacin reduces tenocyte viability and proteoglycan synthesis in short-term explant cultures of equine tendon.

Fluoroquinolones are an effective, broad-spectrum antibiotic used to treat an array of bacterial infections. However, they are associated with an increased risk of tendinopathy and tendon rupture even after discontinuation of treatment. This condition is known as fluoroquinolone-associated tendinopathy, the underlying mechanisms of which are poorly understood. While many factors may be involved in the pathophysiology of tendinopathies in general, changes in tenocyte metabolism and viability, as well as alteration of proteoglycan metabolism are prominent findings in the scientific literature. This study investigated the effects of ciprofloxacin, a common fluoroquinolone, on cell viability, proteoglycan synthesis, and proteoglycan mRNA expression in equine superficial digital flexor tendon explants after 96 h treatment with between 1–300 µg/mL ciprofloxacin, and again after 8 days discontinuation of treatment. Ciprofloxacin caused significant reductions in cell viability by between 25–33% at all dosages except 10 µg/mL, and viability decreased further after 8 days discontinuation of treatment. Proteoglycan synthesis significantly decreased by approximately 50% in explants treated with 100 µg/mL and 300 µg/mL, however this effect reversed after 8 days in the absence of treatment. No significant mRNA expression changes were observed after the treatment period with the exception of versican which was down-regulated at the highest concentration of ciprofloxacin. After the recovery period, aggrecan, biglycan and versican genes were all significantly downregulated in explants initially treated with 1–100 µg/mL. Results from this study corroborate previously reported findings of reduced cell viability and proteoglycan synthesis in a whole tissue explant model and provide further insight into the mechanisms underlying fluoroquinolone-associated tendinopathy and rupture. This study further demonstrates that certain ciprofloxacin induced cellular changes are not rapidly reversed upon cessation of treatment which is a novel finding in the literature.

The role of Gene Mutations (gyrA, parC) in Resistance to Ciprofloxacin in Clinical Isolates of Pseudomonas Aeruginosa

Background & Objective:Pseudomonas aeruginosa is an opportunistic pathogen and one of the most common causes of nosocomial infections. This bacterium's antibiotic resistance to the common fluoroquinolone antibiotics, especially ciprofloxacin, is due to mutations in the gyrA and parC genes. This study aimed to investigate the effect of the mutation in (gyrA, parC) on ciprofloxacin resistance in clinical isolates of Pseudomonas aeruginosa.Methods:A total of 140 clinical samples were collected from hospitals. The samples were identified by standard biochemical tests, and the antibiotic resistance was investigated by the disk diffusion method. DNA was extracted from 30 isolates, and PCR was performed. PCR-sequencing was carried out to assess gyrA and parC mutations in drug-resistant isolates. NCBI-Blast and MEGA7 software was used to analyze the nucleotide sequences.Results:30 clinical isolates were 80% resistant to ciprofloxacin; meanwhile, in 21 samples, mutations were observed. 87/5% of mutations were related to gyrA (Thr83 → Ile), 79/16 % parC (Ser87 → Leu), and 4/18% (Glu91 → Lys). The antibiotic resistance to ciprofloxacin and mutations in gyrA and parC genes in resistant isolates are significantly related to each other (P<0.05). Conclusion:The mutations in the gyrA and parC genes play an essential role in resistance to ciprofloxacin in clinical isolates of Pseudomonas aeruginosa.

Fluoroquinolone-Induced Aortic Injury

According to clinical studies, the use of fluoroquinolone antibacterial agents is associated with such rare, but serious adverse reactions as aortic injuries. The aim of the study was to analyse scientific literature data on the risk of aortic injury during fluoroquinolone treatment. The analytical review showed that the risk factors for fluoroquinolone-induced aortic injury are male gender, age over 45 years, underlying aortic disease, as well as smoking and associated atherosclerosis. Clinical and morphological forms of fluoroquinolone-associated aortic injuries include dilatation (aneurysm development), dissection, and rupture. The analysis of data on the association between aortic injuries and the use of most common fluoroquinolones (ciprofloxacin, levofloxacin, and moxifloxacin) showed that development of aneurysm and dissection was most often observed for levofloxacin, and least often for ciprofloxacin. The mechanism of aortic injury is due to fluoroquinolone-mediated activation of matrix metalloproteinases which damage elastic components of vascular walls, as well as reduction in lysyl oxidase expression and collagen synthesis. The ability of fluoroquinolones to form complexes with magnesium ions reduces the availability of magnesium to the cell enzyme systems, which delays synthesis of extracellular matrix structural proteins, leads to metalloproteinase activation and calcification of the vascular walls. Prevention, early detection, and timely management of the above-mentioned issues depend on the awareness of different medical specialists about the risks of aortic injury associated with the use of fluoroquinolone antibiotics.

Effects of subinhibitory quinolone concentrations on functionality, microbial community composition, and abundance of antibiotic resistant bacteria and qnrS in activated sludge

Wastewater treatment plants (WWTPs) are continuously exposed to sub-inhibitory concentrations of antibiotics that are thought to contribute to the spreading of antibiotic resistant bacteria and antibiotic resistance genes, which are eventually released to downstream environments through effluents. In order to understand the effects of sub-inhibitory concentrations of antibiotics on sludge microbiome and resistome, we spiked a conventional activated sludge (CAS) model system with ciprofloxacin, a common fluoroquinolone antibiotic, from 0.0001 mg/L (about twice the typical ciprofloxacin concentration observed in municipal wastewater) up to 0.1 mg/L (one order of magnitude below the clinical MIC for Enterobacteriaceae) for 151 days. The abundance of ciprofloxacin resistant bacteria and qnrS, a plasmid-associated gene that confers resistance to quinolones, in activated sludge and in effluents of control and spiked CAS reactors, showed no measurable effect of the antibiotic amendment. This was also true for the bacterial community structure and for indicators of WW treatment such as N removal efficiency. Surprisingly, temporal fluctuations in both reactors could explain the observed internal variability of these antibiotic resistance determinants better than the hypothesized antibiotic-driven selective pressure. Overall, this work shows that the core sludge microbiome in CAS systems is resilient to sub-inhibitory concentrations of ciprofloxacin at a functional, structural, and antibiotic resistance levels.

Detection of Second Line Drug Resistance among Drug Resistant Mycobacterium Tuberculosis Isolates in Botswana.

The emergence and transmission of multidrug resistant (MDR) and extensively drug resistant (XDR) Mycobacterium tuberculosis (M.tb) strains is a threat to global tuberculosis (TB) control. The early detection of drug resistance is critical for patient management. The aim of this study was to determine the proportion of isolates with additional second-line resistance among rifampicin and isoniazid resistant and MDR-TB isolates. A total of 66 M.tb isolates received at the National Tuberculosis Reference Laboratory between March 2012 and October 2013 with resistance to isoniazid, rifampicin or both were analyzed in this study. The genotypes of the M.tb isolates were determined by spoligotyping and second-line drug susceptibility testing was done using the Hain Genotype MTBDRsl line probe assay version 2.0. The treatment outcomes were defined according to the Botswana national and World Health Organization (WHO) guidelines. Of the 57 isolates analyzed, 33 (58%) were MDR-TB, 4 (7%) were additionally resistant to flouroquinolones and 3 (5%) were resistant to both fluoroquinolones and second-line injectable drugs. The most common fluoroquinolone resistance-conferring mutation detected was gyrA A90V. All XDR-TB cases remained smear or culture positive throughout the treatment. Our study findings indicate the importance of monitoring drug resistant TB cases to ensure rapid detection of second-line drug resistance.

Mechanism of Action of Mycobacterium tuberculosis Gyrase Inhibitors: A Novel Class of Gyrase Poisons.

Tuberculosis is one of the leading causes of morbidity worldwide, and the incidences of drug resistance and intolerance are prevalent. Thus, there is a desperate need for the development of new antitubercular drugs. Mycobacterium tuberculosis gyrase inhibitors (MGIs) are napthyridone/aminopiperidine-based drugs that display activity against M. tuberculosis cells and tuberculosis in mouse models [Blanco, D., et al. (2015) Antimicrob. Agents Chemother. 59, 1868-1875]. Genetic and mutagenesis studies suggest that gyrase, which is the target for fluoroquinolone antibacterials, is also the target for MGIs. However, little is known regarding the interaction of these drugs with the bacterial type II enzyme. Therefore, we examined the effects of two MGIs, GSK000 and GSK325, on M. tuberculosis gyrase. MGIs greatly enhanced DNA cleavage mediated by the bacterial enzyme. In contrast to fluoroquinolones (which induce primarily double-stranded breaks), MGIs induced only single-stranded DNA breaks under a variety of conditions. MGIs work by stabilizing covalent gyrase-cleaved DNA complexes and appear to suppress the ability of the enzyme to induce double-stranded breaks. The drugs displayed little activity against type II topoisomerases from several other bacterial species, suggesting that these drugs display specificity for M. tuberculosis gyrase. Furthermore, MGIs maintained activity against M. tuberuclosis gyrase enzymes that contained the three most common fluoroquinolone resistance mutations seen in the clinic and displayed no activity against human topoisomerase IIα. These findings suggest that MGIs have potential as antitubercular drugs, especially in the case of fluoroquinolone-resistant disease.

PP-22 Adherence to labelling guidelines, the case of fluoroquinolones. results of a retrospective multicenter drug utilisation study

Introduction Labeledpediatric indications for prescription of fluoroquinolones (FQ) are limited. Furthermore, the safety of systemic FQ for growing children has been debated for a long time.1,2 Nevertheless, prescribing FQ for children can be advantageous. First, FQ cover a broad spectrum of bacteriae.3 Second, pharmacokinetic (PK) characteristics of systemic FQ are favourable. The bioavailability of common FQ agents is usually high and FQ typically penetrate in deep compartments.4,5 In this retrospective multicenter drug utilisation study, we aimed to investigate indications for FQ prescription in a population of children hospitalised in two Belgian university children’s hospitals. Additionally, another goal was to assess the adequacy of prescribed doses, and risk factors for incorrectly dosed FQ prescriptions within our population. Methods Using data obtained from electronic medical files, the study included all children who received a sys-temic FQ prescription in two Belgian university children’s hospitals between 2010–2013. Two authors reviewed pre-scribed daily doses. Univariate and multivariate logistic regression models were used to analyse risk factors for inadequately dosing. Results A total of 262 FQ prescriptions for unique pa-tients were identified. Most children (57.6%) had signifi-cant chronic comorbidity such as any type of cancer, a neurologic disease, or congenital anomalies of the kid-neys and urinary tract. Ciprofloxacin was by far the most frequently prescribed FQ, representing 253 prescriptions (96.6%). Overall, the number of on-label FQ prescriptions was 43 (16.4%), and prescription was guided by a micro-bial culture in 62 cases (35.1%). 79 prescriptions (30.2%), of which 78 ciprofloxacin prescriptions, were considered to be inaccurately dosed. Underdosing was the most common type, as 57.1% of all inaccurately dosed pre-scriptions were underdosed. In the univariate logistic regression analysis, children younger than 6 years of age were at particular risk of receiving an inadequately dosed prescription. In the final multivariate logistic regression model, when controlled for the sort of FQ prescribed, Odds Ratios for infants and preschool children remained statistically significant. Conclusion FQ were often prescribed off-label and not guided by bacteriological findings in our study popula-tion. Dosing errors were common, particularly in infants and preschool children. FQ prescriptions for children should be improved by specific paediatric antimicrobial stewardship teams.

Determination of aqueous antibiotic solutions using SERS nanogratings

The emergence of antibiotics and their active metabolites in aquatic ecosystem has motivated the development of sensitive and reliable sensors to monitor traces of antibiotics and metabolites in drinking water sources (i.e. surface water). The surface enhanced Raman scattering (SERS) technique, which is widely recognized as a high sensitivity method for molecular vibrational detection, is potentially a powerful tool for trace environmental contamination analysis. The main goal of this work is to demonstrate pharmaceutical and metabolite multiplexing detection using the SERS approach. Periodic metallic nanostructures were fabricated using laser interference lithography (LIL) and used as SERS substrates (platform that supports the SERS effect). The LIL method allowed excellent substrate-to-substrate geometric parameters variations; for instance, the variations in periodicity were determined to be less than 1%. A common fluoroquinolone (FQ) parent-and-metabolite pair, enrofloxacin (ENRO) and ciprofloxacin (CIPRO), was targeted for multiplexing detection on the relative uniform substrates fabricated by LIL. The quantifications of the analytes mixtures were achieved by chemometric analysis (i.e. non-negative matrix factorization with alternating least square algorithm (NMF-ALS)). The limit of the quantification (LOQ) of the present method is in the ppm-level with less than 10% spatial variation in the SERS signal.

Development of an icELISA and immunochromatographic strip for detection of norfloxacin and its analogs in milk

ABSTRACTWe developed a monoclonal antibody (mAb) to detect norfloxacin (NOR) using a novel hapten by introducing an amino group via amido linkage into the piperazine ring of NOR. The sensitivity of an indirect competitive enzyme-linked immunosorbent assay (icELISA) based on this mAb showed an improved IC50 value from 1.18 to 0.12 ng/mL and the limit of detection from 0.37 to 0.05 ng/mL by using a heterologous coating (pazufloxacin coupled to ovalbumin). The recovery rate for NOR in milk ranged from 77.3% to 117.8%. Cross-reactivity (CR) experiments showed good CR with nine common fluoroquinolone analogs: pefloxacin, lomfloxacin, ciprofloxacin, enrofloxacin, dafloxacin, sparfloxacin, ofloxacin, marbofloxacin and flumequine. Furthermore, based on this antigen–antibody combination, an immunochromatographic strip with cut-off value of 1 ng/mL was developed. Given their good sensitivity and CR, the developed icELISA and immunochromatographic strip could be useful for detection of NOR and its analogs in milk.

Fluoroquinolone Resistant Rectal Colonization Predicts Risk of Infectious Complications after Transrectal Prostate Biopsy

Infection after transrectal prostate biopsy has become an increasing concern due to fluoroquinolone resistant bacteria. We determined whether colonization identified by rectal culture can identify men at high risk for post-transrectal prostate biopsy infection. Six institutions provided retrospective data through a standardized, web based data entry form on patients undergoing transrectal prostate biopsy who had rectal culture performed. The primary outcome was anypost-transrectal prostate biopsy infection and the secondary outcome was hospital admission 30 days after transrectal prostate biopsy. We used chi-square and logistic regression statistical analysis. A total of 2,673 men underwent rectal culture before transrectal prostate biopsy from January 1, 2007 to September 12, 2013. The prevalence of fluoroquinolone resistance was 20.5% (549 of 2,673). Fluoroquinolone resistant positive rectal cultures were associated with post-biopsy infection (6.6% vs 1.6%, p <0.001) and hospitalization (4.4% vs 0.9%, p <0.001). Fluoroquinolone resistant positive rectal culture increased the risk of infection (OR 3.98, 95% CI 2.37-6.71, p <0.001) and subsequent hospital admission (OR 4.77, 95% CI 2.50-9.10, p <0.001). If men only received fluoroquinolone prophylaxis, the infection and hospitalization proportion increased to 8.2% (28 of 343) and 6.1% (21 of 343), with OR 4.77 (95% CI 2.50-9.10, p <0.001) and 5.67 (95% CI 3.00-10.90, p <0.001), respectively. The most common fluoroquinolone resistant bacteria isolates were Escherichia coli (83.7%). Limitations include the retrospective study design, nonstandardized culture and interpretation of resistance methods. Colonization of fluoroquinolone resistant organisms in the rectum identifies men at high risk for infection and subsequent hospitalization from prostate biopsy, especially in those with fluoroquinolone prophylaxis only.

A new clone sweeps clean: the enigmatic emergence of Escherichia coli sequence type 131.

Escherichia coli sequence type 131 (ST131) is an extensively antimicrobial-resistant E. coli clonal group that has spread explosively throughout the world. Recent molecular epidemiologic and whole-genome phylogenetic studies have elucidated the fine clonal structure of ST131, which comprises multiple ST131 subclones with distinctive resistance profiles, including the (nested) H30, H30-R, and H30-Rx subclones. The most prevalent ST131 subclone, H30, arose from a single common fluoroquinolone (FQ)-susceptible ancestor containing allele 30 of fimH (type 1 fimbrial adhesin gene). An early H30 subclone member acquired FQ resistance and launched the rapid expansion of the resulting FQ-resistant subclone, H30-R. Subsequently, a member of H30-R acquired the CTX-M-15 extended-spectrum beta-lactamase and launched the rapid expansion of the CTX-M-15-containing subclone within H30-R, H30-Rx. Clonal expansion clearly is now the dominant mechanism for the rising prevalence of both FQ resistance and CTX-M-15 production in ST131 and in E. coli generally. Reasons for the successful dissemination and expansion of the key ST131 subclones remain undefined but may include increased transmissibility, greater ability to colonize and/or persist in the intestine or urinary tract, enhanced virulence, and more-extensive antimicrobial resistance compared to other E. coli. Here we discuss the epidemiology and molecular phylogeny of ST131 and its key subclones, possible mechanisms for their ecological success, implications of their widespread dissemination, and future research needs.

English

This study aimed at evaluating the efficacy of four common fluoroquinolone drugs over a year period on some clinical isolates. It also aimed at comparing statistically the average effects of each drug on the isolates. Five different clinical samples (urine, sputum, wound, blood and high vaginal swab [HVS]) from patients attending a university medical centre (between June 2011 and May 2012) were analysed for the purpose of bacteria isolation. The isolates were tested with commonly used flouroquinolones: pefloxacin (30 µg), ofloxacin (30 µg), sparfloxacin (10 µg), and ciprofloxacin (10 µg). Each sensitivity test was done in duplicate and a mean average of zone of inhibition was recorded. One hundred and eighty eight bacteria were isolated: Staphylococcus aureus (44.7%), Streptococcus pyogenes (6.4%), Escherichia coli (28.2%), Pseudomonas aeruginosa (8.5%), Klebsiella pneumonia (8.0%), and Proteus mirabilis (4.3%). All drugs were equally potent against the isolates, but a higher potency was seen in ofloxacin against P. mirabilis. The fluoroquinolones are a group of broad spectrum drugs effective in clinical cases. Their efficacy should be preserved by ensuring strict compliance to local drug policies. Key words: Clinical, fluoroquinolones, efficacy.