Seasonal distribution and dynamic evolution of antibiotics and evaluation of their resistance selection potential and ecotoxicological risk at a wastewater treatment plant in Jinan, China.

The seasonal distribution and dynamic evolution of antibiotics in wastewater from main treatment areas and in sludge and their resistance selection potential and ecotoxicological risk were studied at a municipal wastewater treatment plant in Jinan, East China. Ten antibiotics were selected, and all were detected in wastewater and sludge samples, with fluoroquinolones showing the highest detection concentrations and frequencies. Seasonal fluctuations in the antibiotic concentrations in the influent, effluent, and sludge were observed, with the highest values in winter in most cases. The dynamic evolution of antibiotics during the treatment process differed among the seasons. The antibiotic removal efficiencies were incomplete, ranging from - 40.47 to 100%. Mass balance analysis showed that sulfonamides, roxithromycin, and metronidazole were mainly removed through biological processing, whereas fluoroquinolones, doxycycline, and chloramphenicol were removed through sludge adsorption. Levofloxacin, as well as a mixture of the 10 antibiotics from the effluent, could pose a low ecotoxicological risk to Daphnia in the receiving waters. Additionally, levofloxacin and ciprofloxacin in the effluent and ciprofloxacin and metronidazole in the sludge may facilitate the selection of antibiotic-resistant bacteria in the environment.

Unraveling the Toxicity Associated with Ciprofloxacin Biodegradation in Biological Wastewater Treatment.

Incomplete mineralization of antibiotics in biological sludge systems poses a risk to the environment. In this study, the toxicity associated with ciprofloxacin (CIP) biodegradation in activated sludge (AS), anaerobic methanogenic sludge (AnMS), and sulfur-mediated sludge (SmS) systems was examined via long-term bioreactor tests and a series of bioassays. The AS and AnMS systems were susceptible to CIP and its biotransformation products (TPs) and exhibited performance deterioration, while the SmS system exhibited high tolerance against the toxicity of CIP and its TPs along with excellent pollutant removal. Up to 14 TPs were formed via piperazinyl substituent cleavage, defluorination, decarboxylation, acetylation, and hydroxylation reactions in AS, AnMS, and SmS systems. Biodegradation of CIP in the AS, AnMS, and SmS systems, however, could not completely eliminate its toxicity as evident from the inhibition of Vibrio fischeri luminescence along with Escherichia coli K12 and Bacillus subtilis growth. The anaerobic systems (AnMS and SmS) were more effective than the aerobic AS system at CIP biodegradation, significantly reducing the antibacterial activity of CIP and its TPs in the aqueous phase. In addition, the quantitative structure-activity relationship analysis indicated that the TPs produced via decarboxylation and hydroxylation (TP2 and TP4) as well as by cleavage of piperazine (TP12, TP13, and TP14) exhibited higher toxicity than CIP. The findings of this study provide insights into the toxicity and possible risks associated with CIP biodegradation in biological wastewater treatment.

Mechanochemical treatment for degradation of ciprofloxacin (CIP) in solutions.

Ciprofloxacin (CIP) is a kind of widely used fluoroquinolone antibiotic, and the widespread presence of CIP in aquatic environment has become a serious issue. Mechanochemical treatment (MCT), as an effective approach to degrade persistent organic pollutants, has many advantages of low cost, simplicity, and being environmentally innocuous. However, little attention has been paid to employing MCT to treat effluents containing CIP. In this study, MCT was introduced to degrade CIP in aquatic solutions. A series of CIP degradation experiments were conducted by a planetary ball mill, and the influences of main parameters on CIP degradation efficiency were investigated. Furthermore, an optimum combination was selected through orthogonal experiments, and CIP degradation efficiency could reach as high as 99% in certain conditions. Besides, the biotoxicity of CIP solution was also studied. MCT exhibits satisfying performance for degrading CIP in solutions, which makes MCT a promising approach to CIP elimination and also encourages further applications in treating effluents containing other organic pollutants.

An Examination of the Effect of Rutin against Neurotoxicity Induced by Ciprofloxacin Antibiotic in Wistar Rats.

Rutin is a citrus flavonoid that exists in different types of food, such as fruits, tea, as well as vegetables, and is considered a natural antioxidant. This study aimed to investigate the therapeutic role of Rutin in oxidative stress-induced in Wistar rats exposed to Ciprofloxacin (CPX). The study included 36 healthy adult Wistar rats, which were randomly divided into six groups (n=6). The control group (C) received normal drinking water for 20 days. The first treatment group (T1) received Rutin at a dose of 50 mg/kg of b.w for 20 days. The second treatment group (T2) received CPX antibiotic at a dose of 14 mg/kg of b.w for 20 days. The third treatment group (T3) received Rutin at a dose of 50 mg/kg of b.w for 20 days, and afterward, they received CPX antibiotic at a dose of 14 mg/kg of b.w for 20 days. The fourth treatment group (T4) received CPX antibiotic at a dose of 14 mg/kg of b.w for 20 days, and then, they received Rutin at a dose of 50 mg/kg of b.w for 20 days. The fifth treatment group (T5) received CPX antibiotic at a dose of 14 mg/ kg of b.w and Rutin at a dose of 50 mg/ kg of b.w together for 20 days. All the treatments were administrated by oral gavage. Analysis of the recorded data showed a significant increase (P<0.05) in the concentration of Methylenedioxyamphetamine (MDA) in the T2 group, compared to the other groups. The MDA level significantly (P<0.05) increased in the T3 group (2.29±0.04), compared to the C (1.71±0.01), T1 (1.54±0.04), T4 (1.18±0.02), and T5 (1.29±0.03) groups. However, there were no significant differences (P<0.05) between the C (1.71±0.01) and T1 (1.54±0.04) groups, as well as the T4 (1.18±0.02) and T5 (1.29±0.03) groups with regards to the MDA. The results clarified a significant increase (P<0.05) in the antioxidant activity, Glutathione (GSH), Superoxide dismutase (SOD), and Catalase (CAT) contents in the T1 group, determined at 5.91±0.26, 5.78±0.02, and 1.98±0.05, respectively, compared to the other groups. The lowest antioxidant activity, GSH, SOD, and CAT contents were recorded in the T2 group, in comparison with the other groups (P<0.05). The findings revealed that the level of SOD, GSH, and CAT in the T4 and T5 groups significantly (P<0.05) increased, compared to the T2 and T3 groups. Histological examination of the slides obtained from the brain demonstrated that in the T2 group, some histopathological changes were observed, compared to the C, T1, T4, and T5 groups. These changes were as follows: 1) damaged and clear blood vessel congestion with the deposition of fibrous networks, 2) brain edema, 3) multiple necrotic foci, 4) accumulation of neutrophils, and 5) simple histopathological changes in the brain of animals in the T2 group, compared to the other groups. It is, therefore, concluded that Rutin supplementation at a dose of 50 mg/kg b.w can be the most appropriate dose in protecting brain tissue against tissue damages caused by CPX.

Light microscopy and scanning electron microscopy: A helping tool to identify the adultrant of dye from Curcuma longa L rhizome, and its ecofriendly applications on pharmaceutical products.

The current study was embraced to examine the morphoanatomical distinguishing proof utilizing light microscopy (LM), scanning electron microscopy (SEM) and antibacterial activities of turmeric extract utilizing amoxicillin and ciprofloxacin. Cross over part of the rhizome is roundabout in structure. The peripheral layer is the periderm which comprises of 6-7 layers of digressively lengthened cells. This is trailed by an expansive cortex made of flimsy walled parenchyma cells with intercellular spaces. The antibacterial activities of turmeric extract in blend with drug items like amoxicillin and ciprofloxacin was likewise examined at various fixations. Different turmeric samples and drug items were gathered from various shops of Lahore. The samples were analyzed for antibacterial activities by utilizing pour plate method. In general outcomes showed fundamentally higher zone of inhibition of turmeric extract in combination with ciprofloxacin and lower zone of inhibition of turmeric extract in combination with amoxicillin. It is inferred that turmeric extract have hostile impact in blend with amoxicillin. Thus, the combination of turmeric extract with antimicrobial (amoxicillin) diminished the intensity of antibiotic. The turmeric extract have more antibacterial activity in mix with ciprofloxacin. Thus, the blend of turmeric extract with antibiotic (ciprofloxacin) expanded the intensity of antibiotic. RESEARCH HIGHLIGHTS: Morphoanatomical study of Turmeric rhizome using light microscopy (LM) and scanning electron microscopy (SEM). The antibacterial activities of turmeric extract like amoxicillin and ciprofloxacin was also investigated at different concentrations.

Environmental Risk and Risk of Resistance Selection Due to Antimicrobials' Occurrence in Two Polish Wastewater Treatment Plants and Receiving Surface Water.

In this study, a screening of 26 selected antimicrobials using liquid chromatography coupled to a tandem mass spectrometry method in two Polish wastewater treatment plants and their receiving surface waters was provided. The highest average concentrations of metronidazole (7400 ng/L), ciprofloxacin (4300 ng/L), vancomycin (3200 ng/L), and sulfamethoxazole (3000 ng/L) were observed in influent of WWTP2. Ciprofloxacin and sulfamethoxazole were the most dominant antimicrobials in influent and effluent of both WWTPs. In the sludge samples the highest mean concentrations were found for ciprofloxacin (up to 28 µg/g) and norfloxacin (up to 5.3 µg/g). The removal efficiency of tested antimicrobials was found to be more than 50% for both WWTPs. However, the presence of antimicrobials influenced their concentrations in the receiving waters. The highest antimicrobial resistance risk was estimated in influent of WWTPs for azithromycin, ciprofloxacin, clarithromycin, metronidazole, and trimethoprim and in the sludge samples for the following antimicrobials: azithromycin, ciprofloxacin, clarithromycin, norfloxacin, trimethoprim, ofloxacin, and tetracycline. The high environmental risk for exposure to azithromycin, clarithromycin, and sulfamethoxazole to both cyanobacteria and eukaryotic species in effluents and/or receiving water was noted. Following the obtained results, we suggest extending the watch list of the Water Framework Directive for Union-wide monitoring with sulfamethoxazole.

Exploring microbial community structure and biological function in manured soil during ten repeated treatments with chlortetracycline and ciprofloxacin.

The changes of enzyme activities, microbial community structure and function, and the diversity and resistance level of antibiotic-resistant bacteria (ARB) were studied in soil during ten repeated treatments with chlortetracycline (CTC) and/or ciprofloxacin (CIP) together with organic manure (OM) under laboratory conditions. The activities of neutral phosphatase (NPA) and catalase (CAT) displayed the suppression-recovery-stimulation trend in the OM&CTC treatment but the stimulation trend in the OM&CTC&CIP treatment. The NPA was stimulated but the CAT was little affected in the OM&CIP treatment. Soil microbial functional diversity displayed the suppression-recovery-stimulation trend in the OM&CTC and OM&CTC&CIP treatments and the stimulation-suppression trend in the OM&CIP treatment with the treatment frequency. Metagenomic analysis showed that the relative abundances of Actinobacteria and Firmicutes in the antibiotic treatment significantly increased by 0.5-235.6%, but that of Proteobacteria decreased by 0.2-27.3% compared to the control with the treatment frequency. Furthermore, the relative abundances of dominant bacterial genera including Streptomyces, Actinomadura, Mycobacterium, and Streptococcus in the antibiotic treatment significantly increased by 1.1-10433.3% compared to the control. Meanwhile, repeated antibiotic treatments induced a significant increase in the diversity and resistance level of ARB isolates, especially in the OM&CTC treatment. It is concluded that repeated treatments with CTC and/or CIP can alter enzyme activities, microbial community structure and function, and increase the diversity and resistance level of ARB isolates.

Fate of antibiotics in three distinct sludge treatment wetlands under different operating conditions.

Sludge treatment wetlands (STWs) have recently been used to treat surplus sludge. However, the distribution of antibiotics involved in the process has not been comprehensively investigated. This study aimed to evaluate the fate of two antibiotics, i.e., ciprofloxacin (CIP) and azithromycin (AZM) in STWs during the treatment of surplus sludge. Three pilot-scale STWs units-S1 with aeration tubes, S2 with aeration tubes and reed planting, and S3 with reed planting-were constructed and operated under feeding followed by resting periods. The results showed that antibiotic content in residual sludge decreased over time and unit S2 performed the best in terms of antibiotic removal. Planting reed considerably improved the antibiotic removal performance of the STWs. Biodegradation and absorption resulted in removal of most of the antibiotics in the test units. Less than 2% of the antibiotics was taken up by plants, whereas <5% of the influent antibiotics left the STW units through the drainage discharge. Overall, STW units contributed to effectively decrease CIP and AZM to 41-72% and 49-84%, respectively.

An automated on-line turbulent flow liquid-chromatography technology coupled to a high resolution mass spectrometer LTQ-Orbitrap for suspect screening of antibiotic transformation products during microalgae wastewater treatment.

The evaluation of wastewater treatment capabilities in terms of removal of water pollutants is crucial when assessing water mitigation issues. Not only the monitoring of target pollutants becomes a critical point, but also the transformation products (TPs) generated. Since these TPs are very often unknown compounds, their study in both wastewater and natural environment is currently recognized as a tedious task and challenging research field. In this study, a novel automated suspect screening methodology was developed for a comprehensive assessment of the TPs generated from nine antibiotics during microalgae water treatment. Three macrolides (azithromycin, erythromycin, clarithromycin), three fluoroquinolones (ofloxacin, ciprofloxacin, norfloxacin) and three additional antibiotics (trimethoprim, pipemidic acid, sulfapyridine) were selected as target pollutants. The analysis of samples was carried out by direct injection in an on-line turbulent flow liquid chromatography-high resolution mass spectrometry (TFC-LC-LTQ-Orbitrap-MS/MS) system, followed by automatic data processing for compound identification. The screening methodology allowed the identification of 40 tentative TPs from a list of software predicted intermediates created automatically. Once known and unknown TPs were identified, degradation pathways were suggested considering the different mechanisms involved on their formation (biotic and abiotic). Results reveal microalgae ability for macrolide biotransformation, but not for other antibiotics such as for fluoroquinolones. Finally, the intermediates detected were included into an in-house library and applied to the identification of tentative TPs in real toilet wastewater treated in a microalgae based photobioreactor (PBR). The overall approach allowed a comprehensive overview of the performance of microalgae water treatment in a fast and reliable manner: it represents a useful tool for the rapid screening of wide range of compounds, reducing time invested in data analysis and providing reliable structural identification.

Enhanced phosphorus and ciprofloxacin removal in a modified BAF system by configuring Fe-C micro electrolysis: Investigation on pollutants removal and degradation mechanisms.

A modified biological aerated filter (BAF) system configured Fe-C micro electrolysis was applied to enhance phosphorus and ciprofloxacin (CIP) removal. A novel sludge ceramic and sintering ferric-carbon ceramic (SFC) were separately packed into a lab-scale BAF and Fe-C micro electrolysis reactor. The BAF and Fe-C micro electrolysis coupled system was operated about 230days. The enhancement of phosphorus and ciprofloxacin removals by Fe-C micro electrolysis, the degradation mechanisms of CIP and the variations of microbial population were investigated. The removal efficiencies of chemical oxygen demand (CODcr), ammonia (NH4-N), total phosphorus (TP) and CIP reached about 95%, 95%, 80% and 85% in the combined process, respectively. Configuring Fe-C micro electrolysis significantly enhanced phosphorus and CIP removal, whereas had no promotion on N removal. Four main degradation pathways were proposed according to the LC-MS analysis. More than 12 degradation products were detected through the treatment of Fe-C micro electrolysis and only 3 biodegraded products with low concentration were identified in BAF effluent. The high-throughput sequencing analysis showed that the microbial community changed a lot under CIP pressure. The relative abundance of Sphingomonadaceae, Xanthomonadaceae, Bradyrhizobium, Helicobacter and Pseudomonas increased with CIP influent. This study provides a promising process in CIP wastewater treatment.

Accelerated ciprofloxacin biodegradation in the presence of magnetite nanoparticles.

Ciprofloxacin (CIP) biodegradation was investigated using enrichments obtained in the presence of magnetite nanoparticles, CIP and human fecal sewage. CIP addition inhibited methanogenic activity and altered the bacterial community composition. The magnetite-supplemented enrichments significantly promoted CIP biodegradation, especially in the presence of 2-bromoethanesulfonate (BES). When BES was added, CIP biodegradation in the magnetite-supplemented enrichments was 67% higher than in the magnetite-unamended enrichments. Fe (II) concentrations were also significantly increased in the BES and magnetite-supplemented enrichments. This indicated that there might be a positive relationship of CIP biodegradation with microbial reduction of Fe (III) to Fe (II). As for the magnetite-supplemented enrichments, DNA-sequencing analysis revealed that Stenotrophomonas was the dominant genus, while Desulfovibrio became the dominant genus in the presence of BES. These two genera might be related to Fe (III) reduction in the magnetite. The findings provide a strategy for improving CIP biodegradation during waste treatment.

Ciprofloxacin removal during secondary domestic wastewater treatment in high rate algal ponds.

This study investigated the removal of antibiotic ciprofloxacin during the treatment of real wastewater using high rate algal ponds (HRAP). When spiked at 2 mg/L into primary domestic wastewater, ciprofloxacin (CPX) was efficiently removed from laboratory scale photobioreactors continuously operated under various durations of artificial illumination and hydraulic residence times. Subsequent batch tests conducted with reactor microcosms showed CPX removal was mainly caused by photodegradation during daytime, and sorption to biomass during night time. These findings were confirmed during an experiment conducted in a 1000 L pilot HRAP operated outdoors, as well as during outdoor batch assays conducted using pilot HRAP microcosms. While these results highlight a potentially interesting treatment capacity in comparison to conventional biological treatment, further research must confirm these findings at relevant pollutant concentration (ng-µg/L) and determine the fate and potential toxicity of degradation products.

Residue levels and discharge loads of antibiotics in wastewater treatment plants (WWTPs), hospital lagoons, and rivers within Lake Victoria Basin, Kenya.

The detection of antibiotics in water systems has instigated great environmental concern due to the toxicological effects associated with these compounds. Their discharge into the environment results from the ubiquity of use in medical, veterinary, and agricultural practices. Some of the effects of antibiotics include development of antibiotic-resistant bacteria, making it difficult to treat diseases, variation in natural microbial communities, and enzyme activities. In this study, the first comprehensive survey of some frequently used antibiotics namely ampicillin (AMP), amoxicillin (AMX), sulfamethoxazole (SMX), chloramphenicol (CAP), and ciprofloxacin (CPF) within Lake Victoria Basin of Kenya is presented. Sludge and wastewater samples were collected from wastewater treatment plants (WWTPs) and hospital lagoons within the study area. Samples were extracted and cleaned by solid-phase extraction, and analysis was carried out using high-performance liquid chromatography (HPLC). All wastewater samples and sludge collected contained quantifiable levels of the selected antibiotics. The highest concentrations were recorded for AMP with WWTPs and hospitals having 0.36 ± 0.04 and 0.79 ± 0.07 µg/L, respectively. In sludge samples, SMX recorded the highest concentrations of 276 ± 12 ng/g. The high levels in sludge indicate the preferential partition of antibiotics onto solid phase, posing great danger to consumers of crops grown in biosolid-amended soils. The daily discharge loads of antibiotics from nine WWTPs ranged between 80.75 and 3044.9 mg day(-1) with a total discharge of 6395.85 mg day(-1), signifying a high potential of water resource pollution within the region. This report will aid in the assessment of the risks posed by antibiotics released into the environment.

Antibiotics in Wastewater of a Rural and an Urban Hospital before and after Wastewater Treatment, and the Relationship with Antibiotic Use-A One Year Study from Vietnam.

Hospital effluents represent an important source for the release of antibiotics and antibiotic resistant bacteria into the environment. This study aims to determine concentrations of various antibiotics in wastewater before and after wastewater treatment in a rural hospital (60 km from the center of Hanoi) and in an urban hospital (in the center of Hanoi) in Vietnam, and it aims to explore the relationship between antibiotic concentrations in wastewater before wastewater treatment and quantities of antibiotics used in the rural hospital, over a period of one year in 2013. Water samples were collected using continuous sampling for 24 h in the last week of every month. The data on quantities of antibiotics delivered to all inpatient wards were collected from the Pharmacy department in the rural hospital. Solid-phase extraction and high performance liquid chromatography-tandem mass spectrometry were used for chemical analysis. Significant concentrations of antibiotics were present in the wastewater both before and after wastewater treatment of both the rural and the urban hospital. Ciprofloxacin was detected at the highest concentrations in the rural hospital's wastewater (before treatment: mean = 42.8 µg/L; after treatment: mean = 21.5 µg/L). Metronidazole was detected at the highest concentrations in the urban hospital's wastewater (before treatment: mean = 36.5 µg/L; after treatment: mean = 14.8 µg/L). A significant correlation between antibiotic concentrations in wastewater before treatment and quantities of antibiotics used in the rural hospital was found for ciprofloxacin (r = 0.78; p = 0.01) and metronidazole (r = 0.99; p < 0.001).

Comparison of biological and advanced treatment processes for ciprofloxacin removal in a raw hospital wastewater.

The treatability of ciprofloxacin (CIP) antibiotic was investigated using a single aerobic, a single anaerobic, an anaerobic/aerobic sequential reactor system, a sonicator and a photocatalytic reactor with TiO2 nanoparticles in a raw hospital wastewater in Izmir, Turkey. The effects of increasing organic loading on the performance of all biological systems were investigated, while the effects of power and time on the yields of sonication and photocatalysis were determined. The maximum COD and CIP yields were 95% and 83% in anaerobic/aerobic sequential reactor system at an HRT of 10 days and at an OLR of 0.19 g COD/L × day after 50 days of incubation, respectively. The maximum CH4 gas production was 580 mL day(-1) at an HRT of 6.7 days. The maximum COD and CIP yields were 95% and 81% after 45 min sonication time at a power of 640 W and a frequency of 35 kHz while the maximum yield of COD and CIP were 98% and 88% after 45 min UV irradiation time with a UV power of 210 W using 0.5 g L(-1) TiO2. Among the aforementioned treatment processes, it was found that the highest treatment yields for COD (98%) and CIP (88%) pollutants were obtained with the photocatalytic process due to high OH((●)) radical productions.

The occurrence and removal of selected fluoroquinolones in urban drinking water treatment plants.

Fluoroquinolones (FQs) are a widely prescribed group of antibiotics. They enter the aqueous environment, where they are frequently detected, and can lead to a threat to human health. Drinking water treatment plants (DWTPs) play a key role in removing FQs from potable water. This study investigated the occurrence and removal of four selected FQs (norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENR), and ofloxacin (OFL)) in three urban DWTPs in China. The treatment efficacy for each system was simultaneously evaluated. Two of the examined DWTPs used conventional treatment processes. The third used conventional processes followed by additional treatment processes (ozonation-biologically activated carbon (ozonation-BAC) and membrane technology). The average concentrations of the four FQs in the source water and the finished water ranged from 51 to 248 ng/L and from <5 to 46 ng/L, respectively. Based on residual concentrations, the conventional treatment system had a low removal of FQs. In contrast, the addition of advanced treatment processes such as the ozonation-BAC and membranes, substantially improved the removal of FQs. The finding of this study has important implications: even though coagulation-sedimentation and chlorination treatment processes can remove most target FQs, the typical practice of advanced treatment processes is necessary for the further removal.

Removal of ciprofloxacin from water by birnessite.

With more pharmaceuticals and personal care products detected in the surface and waste waters, studies on interactions between these contaminants and soils or sediments have attracted great attention. In this study, the removal of ciprofloxacin (CIP), a fluoroquinolone antibiotic, by birnessite, a layered manganese oxide, in aqueous solution was investigated by batch studies supplemented by X-ray diffraction (XRD) and Fourier transform infrared analyses. Stoichiometric release of exchangeable cations accompanying CIP removal from water confirmed cation exchange as the major mechanism for CIP uptake by birnessite. Interlayer expansion after CIP adsorption on birnessite as revealed by XRD analyses indicated that intercalation contributed significantly to CIP uptake in addition to external surface adsorption. Correlation of CIP adsorption to specific surface area and cation exchange capacity suggested that the former was the limiting factor for CIP uptake. At the adsorption maximum, CIP molecules formed a monolayer on the birnessite surfaces. The adsorbed CIP could be partially removed using a cationic surfactant at a low initial concentration and mostly removed by AlCl3 at a higher initial concentration, which further supported the cation exchange mechanism for CIP removal by birnessite. The results indicated that the presence of layered Mn-oxide in the soil and waste water treatment systems may provide host for CIP accumulation.

Easy sample treatment for the determination of enrofloxacin and ciprofloxacin residues in raw bovine milk by capillary electrophoresis.

An easy, selective, and sensitive method has been developed for the determination of enrofloxacin (ENR) and its main active metabolite, ciprofloxacin (CIP), in raw bovine milk using CE with UV detection at 268 nm. Milk samples were prepared by a clean-up/extraction procedure based on protein precipitation with hydrochloride acid followed by being defatted by centrifugation and SPE using a hydrophilic-lipophilic balance cartridge. Optimum separation was obtained using a 50 mM phosphoric acid at pH 8.4 and the total electrophoretic run time was 6 min. Sample preparation by this method yielded clean extracts with quantitative and consistent mean recoveries from 89 to 97% for CIP and from 93 to 98% for ENR. LODs obtained were lower to the maximum residue limits for these fluoroquinolones. The precision of the ensuing method is acceptable; thus, the RSD for peak area and migration time was less than 8.5 and 0.5% for CIP and 9.9 and 0.9% for ENR, respectively. The results showed that the proposed method was efficient showing good recoveries, sensitivity, and precision for the studied compounds and could be satisfactorily applied in routine analysis for the monitoring of ENR and CIP residues in milk, due to its ruggedness and feasibility demonstrated.

Oxidation of antibiotics during water treatment with potassium permanganate: reaction pathways and deactivation.

Recent work demonstrates that three widely administered antibiotics (ciprofloxacin, lincomycin, and trimethoprim) are oxidized by potassium permanganate [KMnO(4), Mn(VII)] under conditions relevant to water treatment operations. However, tests show that little to no mineralization occurs during reactions with Mn(VII), so studies were undertaken to characterize the reaction products and pathways and to assess the effects of Mn(VII)-mediated transformations on the antibacterial activity of solutions. Several oxidation products were identified for each antibiotic by liquid chromatography-tandem mass spectrometry (LC-MS/MS). For ciprofloxacin, 12 products were identified, consistent with oxidation of the tertiary aromatic and secondary aliphatic amine groups on the piperazine ring and the cyclopropyl group. For lincomycin, seven products were identified that indicate structural changes to the pyrrolidine ring and thioether group. For trimethoprim, seven products were identified, consistent with Mn(VII) reaction at C═C double bonds on the pyrimidine ring and the bridging methylene group. Oxidation pathways are proposed based on the identified products. Bacterial growth inhibition bioassays (E. coli DH5α) show that the mixture of products resulting from Mn(VII) reactions with the antibiotics collectively retain negligible antibacterial potency in comparison to the parent antibiotics. These results suggest that permanganate can be an effective reagent for eliminating the pharmaceutical activity of selected micropollutants during drinking water treatment.