Bacteriostatic Antibiotics Research Articles

Selenium-mediated protection in reversing the sensitivity of bacterium to the bactericidal antibiotics

Inducing production of damaging reactive oxygen species (ROS) is an important criterion to distinguish the bactericidal antibiotics from bacteriostatic antibiotics. Selenoenzymes were generally recognized to be a powerful antioxidant capable of scavenging free radicals, protecting the cells from the harmful effects of ROS. Therefore, the present study was carried out to investigate the selenium (Se)-mediated protection in reversing antibiotic sensitivity and the role of selenoenzymes in alleviating the negative effects of oxidative stress. The cellular antioxidant activity of Se-enriched bacteria was analyzed, as well as intracellular ROS production and elimination when Se-enriched bacteria in the presence of various antibiotics. Compared to complete inhibition of the parental strain by bactericidal antibiotics, it only exhibited slight and reversible inhibition of Se-enriched Escherichia coli ATCC25922 and Staphylococcus aureus ATCC25923 at the same conditions, which indicated that intracellular selenium provided substantial protection against antibiotics. ROS generation caused by bactericidal antibiotics was confirmed by fluorescence spectrophotometry using 2′, 7′-dichloro- uorescein diacetate (DCFH-DA) as substrate. The time course experiments of pretreatment with selenium showed significant decrease of ROS level at 2h. In summary, the present study provides experimental evidence supporting selenoenzymes has good scavenging effect to ROS and can protect bacteria from oxidative stress injury induced by bactericidal antibiotics.

A Numbers Game: Ribosome Densities, Bacterial Growth, and Antibiotic-Mediated Stasis and Death.

ABSTRACTWe postulate that the inhibition of growth and low rates of mortality of bacteria exposed to ribosome-binding antibiotics deemed bacteriostatic can be attributed almost uniquely to these drugs reducing the number of ribosomes contributing to protein synthesis, i.e., the number of effective ribosomes. We tested this hypothesis with Escherichia coli K-12 MG1655 and constructs that had been deleted for 1 to 6 of the 7 rRNA (rrn) operons. In the absence of antibiotics, constructs with fewer rrn operons have lower maximum growth rates and longer lag phases than those with more ribosomal operons. In the presence of the ribosome-binding “bacteriostatic” antibiotics tetracycline, chloramphenicol, and azithromycin, E. coli strains with 1 and 2 rrn operons are killed at a substantially higher rate than those with more rrn operons. This increase in the susceptibility of E. coli with fewer rrn operons to killing by ribosome-targeting bacteriostatic antibiotics is not reflected in their greater sensitivity to killing by the bactericidal antibiotic ciprofloxacin, which does not target ribosomes, but also to killing by gentamicin, which does. Finally, when such strains are exposed to these ribosome-targeting bacteriostatic antibiotics, the time before these bacteria start to grow again when the drugs are removed, referred to as the post-antibiotic effect (PAE), is markedly greater for constructs with fewer rrn operons than for those with more rrn operons. We interpret the results of these other experiments reported here as support for the hypothesis that the reduction in the effective number of ribosomes due to binding to these structures provides a sufficient explanation for the action of bacteriostatic antibiotics that target these structures.

FLIM Phasor Fingerprint of Bacterial Metabolic State

While a large number of bacteria are deemed beneficial, there is an increasing number of strains associated with pathology, including life-threatening diseases. Moreover, during the last decade, a large number of new infectious strains have been discovered. Treatment is often hindered by emergence multi-drug resistant bacterial strains. Bacteria adapt to adverse environmental conditions by changing their metabolic activity. Further, there also exists metabolic diversity within the same population. Non-invasive assessment of bacterial metabolism could shed light on their physiological status. In this work we employ two-photon fluorescence lifetime imaging microscopy (FLIM) of live, clinically relevant bacteria. FLIM of autofluorescent metabolic coenzyme reduced nicotinamide adenine dinucleotide (phosphate), NAD(P)H, has been extensively exploited for label-free metabolic imaging of mammalian cells to study cancer and other diseases. However, it has not been explored to similar extents in bacteria. We apply phasor analysis to FLIM and create FLIM-phasor fingerprints of bacteria species Escherichia coli, Salmonella enterica serovar Typhimurium, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus epidermidis. The FLIM-phasor method also allows metabolic fingerprinting of individual bacteria within a population. We demonstrate that the NAD(P)H FLIM-phasor fingerprint of bacteria is sensitive to bacteriostatic and bactericidal antibiotics treatment. Furthermore, it varied with cell growth phase of planktonic cultures, suggesting that characteristic shifts in the NAD(P)H FLIM-phasor are representative of modulation of metabolic state of the cells. The FLIM-phasor approach represents a powerful non-invasive imaging technique to study bacterial metabolism and characterize the phasor fingerprint of bacteria under various conditions. This method could prove important in understanding bacteria related pathology, drug response and therapy as well as emergence of newer drug-resistant bacterial strains, all in a label-free manner.Work supported in part by NIH grants P50GM076516,P41GM103540

An effective bioremediation approach for enhanced microbial degradation of the veterinary antibiotic sulfamethazine in an agricultural soil

The veterinary antibiotic Sulfamethazine (SMZ) contaminates soils via manure applications. Like other soil contaminants (herbicides, fungicides, and nematicides), it has to be degraded. The main challenge is that SMZ biodegradation with bacteria is impeded, since SMZ is a bacteriostatic antibiotic, designed to block microbes in their growth. In this study, we enriched the indigenous soil microbial community (including the single strain Microbacterium sp. C448, adapted to SMZ degradation) from a Canadian soil and we present a suitable approach, for soil remediation by inoculating a German soil with this microbial community established on carrier particles, at environmentally relevant concentrations of 1 mg kg−1. When compared with the isolated SMZ-degrading strain (also obtained from Canada), the microbial community outperformed the mineralization rates of the isolated strain in soil. The negligible soil native SMZ mineralization was successfully increased to 44 and 57 % within 46 days, by the microbial community. The sustainability of this increased SMZ mineralization capacity was proven by the rapid mineralization of a second application of 14C-SMZ 112 days after the first. The pronounced SMZ mineralization and the high amount of non-extractable 14C-residues (NER) in the inoculated soil indicate that the NER are mainly of biogenic origin (metabolically fixed 14C). Therefore, the applied inoculation approach decreased the risk of persistent non-extractable SMZ residues. Together with our former studies, this specific soil inoculation approach was tested for three substances with different physico-chemical properties, indicating that this soil bioremediation technique might also be used for other substances.

Macrolide Resistance in Streptococcus pneumoniae.

Streptococcus pneumoniae is a common commensal and an opportunistic pathogen. Suspected pneumococcal upper respiratory infections and pneumonia are often treated with macrolide antibiotics. Macrolides are bacteriostatic antibiotics and inhibit protein synthesis by binding to the 50S ribosomal subunit. The widespread use of macrolides is associated with increased macrolide resistance in S. pneumoniae, and the treatment of pneumococcal infections with macrolides may be associated with clinical failures. In S. pneumoniae, macrolide resistance is due to ribosomal dimethylation by an enzyme encoded by erm(B), efflux by a two-component efflux pump encoded by mef (E)/mel(msr(D)) and, less commonly, mutations of the ribosomal target site of macrolides. A wide array of genetic elements have emerged that facilitate macrolide resistance in S. pneumoniae; for example erm(B) is found on Tn917, while the mef (E)/mel operon is carried on the 5.4- or 5.5-kb Mega element. The macrolide resistance determinants, erm(B) and mef (E)/mel, are also found on large composite Tn916-like elements most notably Tn6002, Tn2009, and Tn2010. Introductions of 7-valent and 13-valent pneumococcal conjugate vaccines (PCV-7 and PCV-13) have decreased the incidence of macrolide-resistant invasive pneumococcal disease, but serotype replacement and emergence of macrolide resistance remain an important concern.

Clinical characteristics of laboratory-confirmed leptospirosis in Okinawa, Japan, 1974-2015: high incidence of Jarisch-Herxheimer reaction.

Leptospirosis is a zoonotic disease known to have wide-ranging clinical manifestations. Despite a number of published case series, culture-confirmed series are few and there is a paucity of data on Jarisch-Herxheimer reaction (JHR) associated with treatment of leptospirosis. Our objective was to describe the clinical and epidemiological factors associated with leptospirosis in an endemic area of Japan, with a focus on the occurrence of JHR, an often unrecognized and likely underestimated phenomenon. We performed a retrospective observational study of laboratory-confirmed leptospirosis at a single center over a 40-year period. We report 100 leptospirosis cases in 99 patients during the period 1974-2015. Seventy-four cases were diagnosed by culture, representing eight different serovars. JHR was seen in 23 (82%) of 28 cases, including 19 (90%) of 21 cases treated with bactericidal antibiotics compared to 4 (57%) of seven cases with bacteriostatic antibiotics (p=0.08). We found a wide variety of clinical manifestations, epidemiological exposures, and causative serovars of disease in an endemic region of Japan. We also found that JHR occurs frequently, and its recognition may be important for the diagnosis and management of leptospirosis in the early stage when laboratory confirmation is pending.

Should azithromycin 1 g be abandoned as a treatment for bacterial STIs? The case for and against

Where did it all go wrong? Azithromycin, a second generation macrolide antimicrobial, has been demonstrated to be highly efficacious both in vitro (low minimum inhibitory concentration (MIC)) and in vivo...

Structural considerations on the selectivity of an immunoassay for sulfamethoxazole

Sulfamethoxazole (SMX), a sulfonamide, is a widely used bacteriostatic antibiotic and therefore a promising marker for the entry of anthropogenic pollution in the environment. SMX is frequently found in wastewater and surface water. This study presents the production of high affinity and selective polyclonal antibodies for SMX and the development and evaluation of a direct competitive enzyme-linked immunosorbent assay (ELISA) for the quantification of SMX in environmental water samples. The crystal structures of the cross-reacting compounds sulfamethizole, N4-acetyl-SMX and succinimidyl-SMX were determined by x-ray diffraction aiming to explain their high cross-reactivity. These crystal structures are described for the first time. The quantification range of the ELISA is 0.82–63µg/L. To verify our results, the SMX concentration in 20 environmental samples, including wastewater and surface water, was determined by ELISA and tandem mass spectrometry (MS/MS). A good agreement of the measured SMX concentrations was found with average recoveries of 97–113% for the results of ELISA compared to LC-MS/MS.

What's new in bacterial meningitis.

What's new in bacterial meningitis.

MATHEMATICAL MODELING OF BACTERIAL RESISTANCE TO ANTIBIOTICS BY MUTATIONS AND PLASMIDS

Diversity of drugs against bacterial infections, and development of resistance to such drugs are increasing. We formulate and analyze a deterministic model for the population dynamics of sensitive and resistant bacteria to multiple bactericidal and bacteriostatic antibiotics, assuming that drug resistance is acquired through mutations and plasmid transmission. Model equilibria are determined from qualitative analysis, and numerical simulations are used to assess temporal dynamics of sensitive and drug-resistant bacteria. The model presents three possibilities: elimination of bacteria, persistence of only resistant bacteria, or coexistence of sensitive and resistant bacteria. Evolution to one of these scenarios depends on thresholds numbers involving sensitive and resistant bacteria.

Lyme Disease: A Bioethical Morass

“Primum non nocere”, “first do no harm” is a medical dictum based in antiquity. Yet, in nearly everything related to Lyme disease, it seems almost entirely disregarded. How ethical is it that we follow the guidelines of the CDC regarding diagnosis when those guidelines require erythema migrans that is clearly recognizable only in one (“bulls-eye rash”) of its multiple presentations? Further, how ethical is it that we are held to guidelines regarding a positive serology that is positive (at best) only 40% of the time? Another questionable ethical situation is the use of a bacteriostatic antibiotic that barely meets the MIC for Borrelia burgdorferi in its ordinarily prescribed regimen. It is also dependent on compliance which is a huge issue because of the gastrointestinal side effects. This antibiotic may clear the rash, but seemingly does little to prevent late findings of the disease. The sub lethal antibiotic dose can be important in the subsequent development of biofilms that lead to a chronic disease state. Lastly, how ethical is it that we have nearly abandoned our patient advocacy and permitted the insurance companies to dictate allowable treatment? And, in as much as Borrelia organisms were found in the brains of Alzheimer’s disease patients over 25 yrs ago and those spirochetes have recently been shown to produce biofilms, how ethical is it that we ignore research underpinning the pathogenesis of this disease? The intent of this work is to discuss how all aspects of Lyme disease (LD) are bioethically challenged. We include Alzheimer’s disease (AD) in the discussion because Lyme spirochetes have been found in, and cultured from, the brains of AD. This makes LD, in its presentation as AD, the equivalent of tertiary neurosyphilis with the only difference being a different spirochete.

Exploring Synergy between Classic Mutagens and Antibiotics To Examine Mechanisms of Synergy and Antibiotic Action.

We used classical mutagens in Gram-negative Escherichia coli to study synergies with different classes of antibiotics, test models of antibiotic mechanisms of action, and examine the basis of synergy. We used 4-nitroquinoline 1-oxide (4NQO), zebularine (ZEB), 5-azacytidine (5AZ), 2-aminopurine (2AP), and 5-bromodeoxyuridine (5BrdU) as mutagens (with bactericidal potency of 4NQO > ZEB > 5AZ > 2AP > 5BrdU) and vancomycin (VAN), ciprofloxacin (CPR), trimethoprim (TMP), gentamicin (GEN), tetracycline (TET), erythromycin (ERY), and chloramphenicol (CHL) as antibiotics. We detected the strongest synergies with 4NQO, an agent that oxidizes guanines and ultimately results in double-strand breaks when paired with the bactericidal antibiotics VAN, TMP, CPR, and GEN, but no synergies with the bacteriostatic antibiotics TET, ERY, and CHL. Each of the other mutagens displays synergies with the bactericidal antibiotics to various degrees that reflect their potencies, as well as with some of the other mutagens. The results support recent models showing that bactericidal antibiotics kill bacteria principally by ultimately generating more double-strand breaks than can be repaired. We discuss the synergies seen here and elsewhere as representing dose effects of not the proximal target damage but rather the ultimate resulting double-strand breaks. We also used the results of pairwise tests to place the classic mutagens into functional antibacterial categories within a previously defined drug interaction network.

Histological and Immunohistochemical Studies on the Kidneys of Pregnant Rats Treated with Clarithromycin

Background: clarithromycin is a semisynthetic macrolide antibiotic, exhibits broad-spectrum activity against gram-positive and gram-negative aerobes. Macrolides are bacteriostatic antibiotics that inhibit protein biosynthesis via reversible binding to the bacterial 50S ribosomal subunit. Macrolides are able to cross placenta and reach the fetus. Aim of the work: the present study is focused on evaluating the effects of antimicrobial drug, clarithromycin on the kidneys of pregnant rats. Material and methods: clarithromycin is orally given to the treated groups of the pregnant rats once daily at different periods of gestation by gastric tube at a dose of 45 mg/kg/day. The excised kidneys were dissected, processed and stained with H & E, PAS, Masson’s trichrome, Feulgen reaction and anti-CD68 immunohistochemical stain then followed by morphometric measurements and statistical analysis. The kidneys were also preserved for DNA fragmentation assay. Results: this study revealed that clarithromycin administration especially to pregnant rats showed different histopathological and histochemical changes in kidney tissues and cellular DNA. Also immunohistochemical anti-inflammatory marker CD68 showed positive reactivity in all treated groups. Conclusion: The presence of histopathological and histochemical changes revealed nephrotoxicity in the pregnant rats after administration of the antimicrobial drug, clarithromycin.

A role for fosfomycin treatment in children for prevention of haemolytic–uraemic syndrome accompanying Shiga toxin-producing Escherichia coli infection

The role of antimicrobial therapy for Shiga toxin-producing Escherichia coli (STEC) infection has not been clearly defined. A prospective study identified antibiotic use as a significant risk factor for subsequent development of haemolytic–uraemic syndrome (HUS). However, early treatment with fosfomycin, a bacteriostatic antibiotic, resulted in a significantly decreased risk of HUS. The aim of this study was to evaluate a role of fosfomycin therapy in the development of HUS in children who contracted STEC infection. The study included 118 children who contracted a STEC infection between 1997 and 2013. A pre-defined questionnaire was utilised to collect patient information regarding age, sex, presenting symptoms (fever, abdominal pain, diarrhoea and bloody stool), results of stool culture examination, initial results of white blood cell counts and C-reactive protein (CRP), use of antibiotics, the timing of introduction of antibiotics, and complications including HUS. Of the 118 patients, 64 were diagnosed with HUS and the remaining 54 did not develop HUS. Multivariate analysis showed that three independent factors (age, initial values of CRP and use of fosfomycin) were significantly associated with the occurrence of HUS; of particular note, the adjusted odds ratio for use of fosfomycin was 0.15 (95% confidence interval 0.05–0.45). Use of fosfomycin within the first 5 days of illness may decrease the development of STEC-related HUS in children.

Ribosome Hibernation Facilitates Tolerance of Stationary-Phase Bacteria to Aminoglycosides

Upon entry into stationary phase, bacteria dimerize 70S ribosomes into translationally inactive 100S particles by a process called ribosome hibernation. Previously, we reported that the hibernation-promoting factor (HPF) of Listeria monocytogenes is required for 100S particle formation and facilitates adaptation to a number of stresses. Here, we demonstrate that HPF is required for the high tolerance of stationary-phase cultures to aminoglycosides but not to beta-lactam or quinolone antibiotics. The sensitivity of a Δhpf mutant to gentamicin was suppressed by the bacteriostatic antibiotics chloramphenicol and rifampin, which inhibit translation and transcription, respectively. Disruption of the proton motive force by the ionophore carbonyl cyanide m-chlorophenylhydrazone or mutation of genes involved in respiration also suppressed the sensitivity of the Δhpf mutant. Accordingly, Δhpf mutants had aberrantly high levels of ATP and reducing equivalents during prolonged stationary phase. Analysis of bacterial uptake of fluorescently labeled gentamicin demonstrated that the Δhpf mutant harbored increased intracellular levels of the drug. Finally, deletion of the main ribosome hibernation factor of Escherichia coli, ribosome modulation factor (rmf), rendered these bacteria susceptible to gentamicin. Taken together, these data suggest that HPF-mediated ribosome hibernation results in repression of the metabolic activity that underlies aminoglycoside tolerance. HPF is conserved in nearly every bacterial pathogen, and the role of ribosome hibernation in antibiotic tolerance may have clinical implications.

Antibiotic efficacy is linked to bacterial cellular respiration

Bacteriostatic and bactericidal antibiotic treatments result in two fundamentally different phenotypic outcomes--the inhibition of bacterial growth or, alternatively, cell death. Most antibiotics inhibit processes that are major consumers of cellular energy output, suggesting that antibiotic treatment may have important downstream consequences on bacterial metabolism. We hypothesized that the specific metabolic effects of bacteriostatic and bactericidal antibiotics contribute to their overall efficacy. We leveraged the opposing phenotypes of bacteriostatic and bactericidal drugs in combination to investigate their activity. Growth inhibition from bacteriostatic antibiotics was associated with suppressed cellular respiration whereas cell death from most bactericidal antibiotics was associated with accelerated respiration. In combination, suppression of cellular respiration by the bacteriostatic antibiotic was the dominant effect, blocking bactericidal killing. Global metabolic profiling of bacteriostatic antibiotic treatment revealed that accumulation of metabolites involved in specific drug target activity was linked to the buildup of energy metabolites that feed the electron transport chain. Inhibition of cellular respiration by knockout of the cytochrome oxidases was sufficient to attenuate bactericidal lethality whereas acceleration of basal respiration by genetically uncoupling ATP synthesis from electron transport resulted in potentiation of the killing effect of bactericidal antibiotics. This work identifies a link between antibiotic-induced cellular respiration and bactericidal lethality and demonstrates that bactericidal activity can be arrested by attenuated respiration and potentiated by accelerated respiration. Our data collectively show that antibiotics perturb the metabolic state of bacteria and that the metabolic state of bacteria impacts antibiotic efficacy.

Minocycline: a bacteriostatic antibiotic with pleiotropic cardioprotective effects.

Minocycline belongs to the family of tetracyclines, which are drugs traditionally approved as antibiotics. Based on preclinical animal cardiac models and clinical neurology trials, this drug has gained special attention as a promising cardiovascular therapeutic agent given its anti-inflammatory, antiapoptotic, antioxidant, and antienzymatic properties. This review focuses on the available evidence for minocycline as a cardioprotective drug, with special attention to mechanisms of action. Ongoing cardiovascular clinical trials are briefly discussed.

The extracellular death factor (EDF) protects Escherichia coli by scavenging hydroxyl radicals induced by bactericidal antibiotics.

The newly discovered extracellular death factor (EDF) is a pentapeptide with the sequence NNWNN in Escherichia coli. It was reported that it participated in the cell death process mediated by toxin-antitoxin system mazEF. Reactive oxygen species (ROS) are recently considered as common factors for bactericidal antibiotics-mediated cell death. Previous study indicated that EDF could scavenge hydroxyl radicals and might act as a signal molecule with dual effects, “death” and “survival”. But the structure-activity relationship of EDF and the effects of EDF on the activity of antibiotics remain unclear. In the present study, our results indicated that tryptophan could be the key residue to the hydroxyl radicals-scavenging activity of EDF, and EDF could protect Escherichia coli from killing by bactericidal antibiotics, but not by DNA-damaging or bacteriostatic antibiotics. Our results could provide novel evidence to understand the role of EDF in drug-resistance.

Chloramphenicol encapsulated in poly-ε-caprolactone-pluronic composite: nanoparticles for treatment of MRSA-infected burn wounds.

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) infection has increased precipitously over the past several decades, with far-reaching health care and societal costs. MRSA infections in the context of burn wounds lead to invasive disease that could potentially cause mortality. Chloramphenicol is a well-known broad-spectrum bacteriostatic antibiotic that has been used since 1949, but due to its hydrophobicity, poor penetration in skin, fast degradation, and toxicity, its application has been hindered. Furthermore, it has been demonstrated that old antibiotics such as chloramphenicol remained active against a large number of currently prevalent resistant bacterial isolates due to their low-level use in the past. Recently, the novel nanoparticulate drug-delivery system has been used and reported to be exceptionally useful for topical therapeutics, due to its distinctive physical characteristics such as a high surface-to-volume ratio and minuscule size. It helps to achieve better hydrophilicity, bioavailability, and controlled delivery with enhanced therapeutic index, which has resulted in decreased toxicity levels compared to the crude drug. Here, we report a novel chloramphenicol loaded with poly(ε-caprolactone) (PCL)-pluronic composite nanoparticles (CAM-PCL-P NPs), physicochemical characterizations, and its bioactivity evaluation in a MRSA-infected burn-wound animal model. CAM-PCL-P NPs could encapsulate 98.3% of the drug in the nanoparticles and release 81% of the encapsulated drug over 36 days with a time to 50% drug release of 72 hours (51%). Nanoparticle suspensions maintained the initial properties with respect to size and encapsulation efficiency, even after 6 months of storage at 4°C and 25°C, respectively (P>0.05). Significant reduction in the level of toxicity was observed for CAM-PCL-P NPs compared with that of free drug as confirmed from hemolytic activity against human blood erythrocytes and cytotoxicity assay against an MCF-7 breast cancer cell line. In vitro antibacterial activities were performed by zone of inhibition, minimum inhibitory concentrations, minimum bacterial concentration, and time-kill assays, which showed that CAM-PCL-P NPs exhibited significantly enhanced anti-MRSA activity against ten clinical isolates of MRSA strains. The augmented activity of CAM-PCL-P NPs was further tested on a MRSA-infected burn-wound animal model and achieved quicker efficacy in MRSA clearance and improved the survival rate compared with free-chloramphenicol treatment. Thus, we propose CAM-PCL-P NPs as a promising novel antimicrobial candidate that may have a good potential for preclinical applications.

Mineralization of synthetic and industrial pharmaceutical effluent containing trimethoprim by combining electro-Fenton and activated sludge treatment

A combined process coupling of an electro-Fenton and a biological degradation was investigated in order to mineralize synthetic and industrial pharmaceutical effluent containing trimethoprim, a bacteriostatic antibiotic. Electro-Fenton degradation of trimethoprim was optimized by means of a Doehlert experimental design, showing that 0.69 mM Fe2+, 466 mA and 30 min electrolysis time were optimal, leading to total trimethoprim removal, while mineralization remained limited, 12% for 30 min electrolysis times. The aromatic and aliphatic by-products were identified and a plausible degradation pathway was proposed. Biodegradability was improved, since the BOD5/COD ratio increased from 0.11 initially to 0.32 and 0.52 after 30 and 60 min electrolysis times respectively, confirmed by activated sludge culture, 47 and 59% mineralization of the byproducts from electrolysis.The relevance of the proposed combined process was then confirmed on an industrial pharmaceutical effluent. Its electrolysis under the above conditions showed an almost total removal of trimethoprim after 180 min of electrolysis, while TOC removal remained low, 14 and 16% for 180 and 300 min reaction times, respectively. Overall removal yields of the industrial effluent during the combined process were therefore 80 and 89% for 180 and 300 min of effluent pretreatment followed by 15 days activated sludge culture, respectively.