Insight into synergetic mechanisms of tetracycline and the selective serotonin reuptake inhibitor, sertraline, in a tetracycline-resistant strain of Escherichia coli

Development of pharmacophore models for AcrB protein and the identification of potential adjuvant candidates for overcoming efflux-mediated colistin resistance

Growing multi-drug resistance (MDR) among ESKAPE pathogens is a huge challenge. Increased resistance to last-resort antibiotics, like colistin, has further aggravated this. Efflux is identified as a major route of colistin resistance. So, finding an FDA-approved efflux inhibitor for potential application as an adjuvant to colistin was the primary objective of this study. E. coli-AcrB pump inhibitors and substrates were used to develop and validate the pharmacophoric model. Drugs confirming this pharmacophore were subjected to molecular docking to identify hits for the AcrB binding pocket. The efflux inhibition potential of the top hit was validated through the in vitro evaluation of the minimum inhibitory concentration (MIC) in combination with colistin. The checkerboard assay was done to demonstrate synergism, which was further corroborated by the Time-kill assay. Ten common pharmacophore hypotheses were successfully generated using substrate/inhibitors. Following enrichment analysis, AHHNR.100 was identified as the top-ranked hypothesis, and 207 unique compounds were found to conform to this hypothesis. The multi-step docking of these compounds against the AcrB protein revealed argatroban as the top non-antibiotic hit. This significantly inhibited the efflux activity of colistin-resistant clinical isolates K. pneumoniae (n = 1) and M. morganii (n = 2). Further, their combination with colistin enhanced the susceptibility of these isolates, and the effect was found to be synergistic. Accordingly, the time-kill assay of this combination showed 8-log and 2-log reductions against K. pneumoniae and M. morganii, respectively. In conclusion, this study found argatroban as a bacterial efflux inhibitor that can be potentially used to overcome efflux-mediated resistance.

Inhibition of Plasmid Conjugation in Escherichia coli by Targeting rbsB Gene Using CRISPRi System

Bacterial conjugation constitutes a major horizontal gene transfer mechanism for the dissemination of antibiotic-resistant genes (ARGs) among human pathogens. The spread of ARGs can be halted or diminished by interfering with the conjugation process. In this study, we explored the possibility of using an rbsB gene as a single target to inhibit plasmid-mediated horizontal gene transfer in Escherichia coli by CRISPR interference (CRISPRi) system. Three single-guide RNAs (sgRNAs) were designed to target the rbsB gene. The transcriptional levels of the rbsB gene, the conjugation-related genes, and the conjugation efficiency in the CRISPRi strain were tested. We further explored the effect of the repressed expression of the rbsB gene on the quorum sensing (QS) system and biofilm formation. The results showed that the constructed CRISPRi system was effective in repressing the transcriptional level of the rbsB gene at a rate of 66.4%. The repressed expression of the rbsB gene resulted in the reduced conjugation rate of RP4 plasmid by 88.7%, which significantly inhibited the expression of the conjugation-related genes (trbBp, trfAp, traF and traJ) and increased the global regulator genes (korA, korB and trbA). The repressed rbsB gene expression reduced the depletion of autoinducer 2 signals (AI-2) by 12.8% and biofilm formation by a rate of 68.2%. The results of this study indicated the rbsB gene could be used as a universal target for the inhibition of conjugation. The constructed conjugative CRISPRi system has the potential to be used in ARG high-risk areas.

Interactions Between Antidepressants and Intestinal Microbiota

The microbiota-gut-brain axis has been shown to influence human health and diseases, including depression. The interactions between drugs and intestinal microbiota are complex and highly relevant to treat diseases. Studies have shown an interaction between antidepressants and intestinal microbiota. Antidepressants may alter the abundance and composition of intestinal microbiota, which are closely related to the treatment outcomes of depression. Intestinal microbiota can influence the metabolism of antidepressants to change their availability (e.g., tryptophan can be metabolized to kynurenine by intestinal microbiota) and regulate their absorption by affecting intestinal permeability. In addition, the permeability of the blood-brain barrier can be altered by intestinal microbiota, influencing antidepressants to reach the central nervous system. Bioaccumulation is also a type of drug-microbiota interaction, which means bacteria accumulate drugs without biotransformation. These findings imply that it is important to consider intestinal microbiota when evaluating antidepressant therapy regimens and that intestinal microbiota can be a potential target for depression treatment.

Disrupting the ArcA Regulatory Network Amplifies the Fitness Cost of Tetracycline Resistance in Escherichia coli

There is an urgent need for strategies to discover secondary drugs to prevent or disrupt antimicrobial resistance (AMR), which is causing >700,000 deaths annually. Here, we demonstrate that tetracycline-resistant (Tet^R) Escherichia coli undergoes global transcriptional and metabolic remodeling, including downregulation of tricarboxylic acid cycle and disruption of redox homeostasis, to support consumption of the proton motive force for tetracycline efflux. Using a pooled genome-wide library of single-gene deletion strains, at least 308 genes, including four transcriptional regulators identified by our network analysis, were confirmed as essential for restoring the fitness of Tet^R E. coli during treatment with tetracycline. Targeted knockout of ArcA, identified by network analysis as a master regulator of this new compensatory physiological state, significantly compromised fitness of Tet^R E. coli during tetracycline treatment. A drug, sertraline, which generated a similar metabolome profile as the arcA knockout strain, also resensitized Tet^R E. coli to tetracycline. We discovered that the potentiating effect of sertraline was eliminated upon knocking out arcA, demonstrating that the mechanism of potential synergy was through action of sertraline on the tetracycline-induced ArcA network in the Tet^R strain. Our findings demonstrate that therapies that target mechanistic drivers of compensatory physiological states could resensitize AMR pathogens to lost antibiotics. IMPORTANCE Antimicrobial resistance (AMR) is projected to be the cause of >10 million deaths annually by 2050. While efforts to find new potent antibiotics are effective, they are expensive and outpaced by the rate at which new resistant strains emerge. There is desperate need for a rational approach to accelerate the discovery of drugs and drug combinations that effectively clear AMR pathogens and even prevent the emergence of new resistant strains. Using tetracycline-resistant (Tet^R) Escherichia coli, we demonstrate that gaining resistance is accompanied by loss of fitness, which is restored by compensatory physiological changes. We demonstrate that transcriptional regulators of the compensatory physiologic state are promising drug targets because their disruption increases the susceptibility of Tet^R E. coli to tetracycline. Thus, we describe a generalizable systems biology approach to identify new vulnerabilities within AMR strains to rationally accelerate the discovery of therapeutics that extend the life span of existing antibiotics.

The potential action of SSRIs in the treatment of skin diseases including atopic dermatitis and slow-healing wounds

Selective serotonin reuptake inhibitors (SSRIs) are used to treat affective and anxiety disorders. Antidepressants have also been shown to have antimicrobial and immunomodulatory effects, which may affect the microbiota-intestinal-brain axis. Studies show that SSRIs have antimicrobial activity both in vivo and in vitro and influence bacteria by inhibiting biofilm, affecting efflux pumps, among others. A huge challenge today is the prevention and treatment of skin diseases, including atopic dermatitis (AD) and slow-healing wounds. Skin diseases including AD and non-healing wounds are serious medical problem. People suffering from these conditions feel constant discomfort, which also affects their psychological state. Research on new treatments for AD and slow-healing wounds is essential because current medications are not fully effective and have many side effects. Exploring new drug groups for AD and slow-healing wounds will allow for the creation of an alternative treatment for these diseases. SSRIs represent a hope for the treatment of skin diseases due to their immunomodulatory and antimicrobial properties.

Tetracycline-loaded magnesium oxide nanoparticles with a potential bactericidal action against multidrug-resistant bacteria: In vitro and in vivo evidence

Worldwide, the emergence of diarrhoea-causing multi-drug resistant (MDR) bacteria has become a crucial problem in everyday life. Tetracycline (TC) is a bacteriostatic agent that has a wide spectrum of antibacterial activity. One potential strategy to enhance the penetration and antibacterial activity of antibiotics is the use of nanotechnology. In this context, this study dealt with the synthesis of TC loading in biocompatible magnesium oxide nanoparticles (MgONPs), its characterization, and the potency of killing against diarrhoea-causing MDR bacteria E. coli and S. flexneri. TC loaded- MgONPs (MgONPs-TC) were characterized by DLS, SEM-EDS, UV-vis spectroscopy, and FTIR techniques with adequate physical properties. Antibacterial and antibiofilm studies indicate that this nanoparticle successfully eradicated both planktonic and sessile forms of those bacteria. It also significantly reduced the production of bacterial EPS, different levels of antioxidant enzymes, and induced reactive oxygen species (ROS) in the bacterial cell as a mode of antibacterial action. In particular, MgONPs-TC were efficient in reducing the colonization of MDR E. coli and S. flexneri in the C. elegans model. Therefore, all these data suggest that MgONPs-TC are a highly promising approach to combating diseases associated with diarrhoea-causing MDR bacteria in the medical field with limited health care budgets.

Combined exposure to non-antibiotic pharmaceutics and antibiotics in the gut synergistically promote the development of multi-drug-resistance in Escherichia coli

The gut microbiota represents an important reservoir of antibiotic-resistant bacteria (ARB), which poses a significant threat to public health. However, little is known about the emergence of ARB in the gut after the combined exposure to antibiotics and non-antibiotic pharmaceutics. Here, Escherichia coli, a common opportunistic pathogen in the gut microbiota, was exposed to the antidepressant duloxetine (2.5 µg/L-25 mg/L) and/or chloramphenicol (6 µg/L-4 mg/L). The resistant strains were isolated to determine the minimum inhibition concentration (MIC) of 29 antibiotics. Then, genome-wide DNA sequencing, global transcriptomic sequencing, and real-time quantitative polymerase chain reaction were performed to quantify the synergy between duloxetine and chloramphenicol. Combined exposure synergistically increased the mutation frequency of chloramphenicol resistance by 2.45-9.01 fold compared with the independent exposure. A combination index reaching 187.7 indicated strong duloxetine and chloramphenicol synergy. The resultant mutants presented heritable enhanced resistance to 12 antibiotics and became ARB to eight antibiotics. Furthermore, combined exposure significantly increased the transcriptomic expression of acrA, acrB, and marA in E. coli, and generated a more robust oxidative stress response. Together with the occurrence of DNA mutations in marR in the mutants, stronger triggers to the AcrAB-TolC transport system and the MlaFEDB ABC transporter via reactive oxygen species (ROS)-induced mutagenesis, verified by gene knockout, contributed to the synergistic enhancement of antibiotic resistance in the combined exposure group. Regardless of whether their formation was induced by duloxetine, chloramphenicol, or their combination, the E. coli mutants showed 1.1-1.7-fold increases in the expression levels of acrA, acrB, acrZ, mdtE, and mdtF. This pattern indicated that the mutants shared the same resistance mechanisms against chloramphenicol, involving the improved efflux pumps AcrAB-TolC and mdtEF. Our findings demonstrated that antibiotics and non-antibiotic pharmaceutics synergistically accelerate the evolution of ARB and may enhance their spread.

Repositioning of non-antibiotic drugs as an alternative to microbial resistance: a systematic review

The global spread of microbial resistance coupled with high costs and slow pace in the discovery of a new antibiotic have made drug repositioning an attractive and promising alternative in the treatment of infections caused by multidrug resistant (MDR) microorganisms. The reuse involves the production of compounds with lower costs and development time, using diversified production technologies. The present systematic review aimed to present a selection of studies published in the last 20 years, which report the antimicrobial activity of non-antibiotic drugs that are candidates for repositioning, which could be used against the current microbial multidrug resistance. A search was performed in the PubMed, SciELO and Google Scholar databases using the following search strategies: [(drug repurposing) OR (drug repositioning) OR (repositioning) AND (non-antibiotic) AND (antibacterial activity) AND (antimicrobial activity)]. Overall, 112 articles were included, which explored the antimicrobial activity in antidepressants, antihypertensives, anti-inflammatories, antineoplastics, hypoglycemic agents, among other drugs. It was concluded that they have significant antimicrobial activity in vitro and in vivo, against standard strain and clinical isolates (Gram-negative and Gram-positive) and fungi. When associated with antibacterials, most of these drugs had their antibacterial activity enhanced. It was also a consensus of the studies included in this review that the presence of aromatic rings in the molecular structure contributes to antimicrobial activity. This review highlights the potential repositioning of several classes of non-antibiotic drugs as promising candidates for repositioning in the treatment of severe bacterial infections of MDR bacteria, extensively resistant (XDR) and pan-resistant (PDR) to drugs.

Nutritional and therapeutic approaches for protecting human gut microbiota from psychotropic treatments

Emerging evidence highlighted the essential role played by the microbiota-gut-brain axis in maintaining human homeostasis, including nutrition, immunity, and metabolism. Much recent work has linked the gut microbiota to many psychiatric and neurodegenerative disorders such as depression, schizophrenia, and Alzheimer's disease. Shared gut microbiota alterations or dysbiotic microbiota have been identified in these separate disorders relative to controls. Much attention has focused on the bidirectional interplay between the gut microbiota and the brain, establishing gut dysbiotic status as a critical factor in psychiatric disorders. Still, the antibiotic-like effect of psychotropic drugs, medications used for the treatment of these disorders, on gut microbiota is largely neglected. In this review, we summarize the current findings on the impact of psychotropics on gut microbiota and how their antimicrobial potency can trigger dysbiosis. We also discuss the potential therapeutic strategies, including probiotics, prebiotics, and fecal transplantation, to attenuate the dysbiosis related to psychotropics intake.

Unravelling the antimicrobial action of antidepressants on gut commensal microbes

Over the past decade, there has been increasing evidence highlighting the implication of the gut microbiota in a variety of brain disorders such as depression, anxiety, and schizophrenia. Studies have shown that depression affects the stability of gut microbiota, but the impact of antidepressant treatments on microbiota structure and metabolism remains underexplored. In this study, we investigated the in vitro antimicrobial activity of antidepressants from different therapeutic classes against representative strains of human gut microbiota. Six different antidepressants: phenelzine, venlafaxine, desipramine, bupropion, aripiprazole and (S)-citalopram have been tested for their antimicrobial activity against 12 commensal bacterial strains using agar well diffusion, microbroth dilution method, and colony counting. The data revealed an important antimicrobial activity (bacteriostatic or bactericidal) of different antidepressants against the tested strains, with desipramine and aripiprazole being the most inhibitory. Strains affiliating to most dominant phyla of human microbiota such as Akkermansia muciniphila, Bifidobacterium animalis and Bacteroides fragilis were significantly altered, with minimum inhibitory concentrations (MICs) ranged from 75 to 800 μg/mL. A significant reduction in bacterial viability was observed, reaching 5 logs cycle reductions with tested MICs ranged from 400 to 600 μg/mL. Our findings demonstrate that gut microbiota could be altered in response to antidepressant drugs.

Global responses to oxytetracycline treatment in tetracycline-resistant Escherichia coli

We characterized the global transcriptome of Escherichia coli MG1655:: tetA grown in the presence of ½ MIC (14 mg/L) of OTC, and for comparison WT MG1655 strain grown with 1//2 MIC of OTC (0.25 mg/L OTC). 1646 genes changed expression significantly (FDR > 0.05) in the resistant strain, the majority of which (1246) were also regulated in WT strain. Genes involved in purine synthesis and ribosome structure and function were top-enriched among up-regulated genes, and anaerobic respiration, nitrate metabolism and aromatic amino acid biosynthesis genes among down-regulated genes. Blocking of the purine-synthesis- did not affect resistance phenotypes (MIC and growth rate with OTC), while blocking of protein synthesis using low concentrations of chloramphenicol or gentamicin, lowered MIC towards OTC. Metabolic-modeling, using a novel model for MG1655 and continuous weighing factor that reflected the degree of up or down regulation of genes encoding a reaction, identified 102 metabolic reactions with significant change in flux in MG1655:: tetA when grown in the presence of OTC compared to growth without OTC. These pathways could not have been predicted by simply analyzing functions of the up and down regulated genes, and thus this work has provided a novel method for identification of reactions which are essential in the adaptation to growth in the presence of antimicrobials.

Conjugating biomaterials with photosensitizers: advances and perspectives for photodynamic antimicrobial chemotherapy

Antimicrobial resistance is threatening to overshadow last century's medical advances. Previously eradicated infectious diseases are now resurgent as multi-drug resistant strains, leading to expensive, toxic and, in some cases, ineffective antimicrobial treatments. Given this outlook, researchers are willing to investigate novel antimicrobial treatments that may be able to deal with antimicrobial resistance, namely photodynamic therapy (PDT). PDT relies on the generation of toxic reactive oxygen species (ROS) in the presence of light and a photosensitizer (PS) molecule. PDT has been known for almost a century, but most of its applications have been directed towards the treatment of cancer and topical diseases. Unlike classical antimicrobial chemotherapy treatments, photodynamic antimicrobial chemotherapy (PACT) has a non-target specific mechanism of action, based on the generation of ROS, working against cellular membranes, walls, proteins, lipids and nucleic acids. This non-specific mechanism diminishes the chances of bacteria developing resistance. However, PSs usually are large molecules, prone to aggregation, diminishing their efficiency. This review will report the development of materials obtained from natural sources, as delivery systems for photosensitizing molecules against microorganisms. The present work emphasizes on the biological results rather than on the synthesis routes to prepare the conjugates. Also, it discusses the current state of the art, providing our perspective on the field.

Systematic stress adaptation of Bacillus subtilis to tetracycline exposure

To alleviate the harmful effects of antibiotics on the environment and human health, the stress response and molecular network of Bacillus under tetracycline stress were investigated using a proteomics approach. During the exposure process, Bacillus subtilis exhibited a strong adaptation mechanism. Cell membrane and intracellular reactive oxygen species (ROS) level returned to normal after 5 h. A total of 312 upregulated and 65 downregulated proteins were identified, mainly involved in metabolism and the synthesis of ribosomes, DNA, and RNA. After tetracycline exposure, the core metabolism network was accelerated to supply precursors for the synthesis of DNA, RNA, proteins, peptidoglycans, and saturated fatty acids that were involved in ribosome protection, and strengthened the cell wall and cell membrane. The signal transduction pathways involved were analyzed in association with the stress response of B. subtilis at 15 min of exposure to tetracycline. The primary damage to the ribosome by tetracycline activated a series of response proteins. Antitoxin and heat-shock proteins were activated for the global regulation of transcription and metabolism. Trigger factor Tig was upregulated to ensure proper initiation of transcription and aerobic respiration. Temperature-sensor protein VicR from the two-component system was used by the cell to regulate the composition of the cell wall and cell membrane. The over-consumption of metabolites, such as phosphoribosyl diphosphate (PRPP), purine nucleoside triphosphate (GTP), and acetyl-CoA forced the cells to assimilate more sugar for glycolysis. To this end, methyl-accepting chemotaxis proteins (MCPs) and sugar transportation protein PtsG were upregulated, simultaneously. Ultimately, peroxidase was activated to eliminate the redundant ROS, to minimize cell damage. These findings presented a system-level understanding of adaption processes of bacteria to antibiotic stress.

In Vitro Activity of Sertraline, an Antidepressant, Against Antibiotic-Susceptible and Antibiotic-Resistant Helicobacter pylori Strains

Antibiotic resistance of Helicobacter pylori, a spiral bacterium associated with gastric diseases, is a topic that has been intensively discussed in last decades. Recent discoveries indicate promising antimicrobial and antibiotic-potentiating properties of sertraline (SER), an antidepressant substance. The aim of the study, therefore, was to determine the antibacterial activity of SER in relation to antibiotic-sensitive and antibiotic-resistant H. pylori strains. The antimicrobial tests were performed using a diffusion-disk method, microdilution method, and time-killing assay. The interaction between SER and antibiotics (amoxicillin, clarithromycin, tetracycline, and metronidazole) was determined by using a checkerboard method. In addition, the study was expanded to include observations by light, fluorescence, and scanning electron microscopy. The growth inhibition zones were in the range of 19–37 mm for discs impregnated with 2 mg of SER. The minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) counted for 2–8 µg/mL and 4–8 µg/mL, respectively. The time-killing assay showed the time-dependent and concentration-dependent bactericidal activity of SER. Bacteria exposed to MBCs (but not sub-MICs and MICs ≠ MBCs) underwent morphological transformation into coccoid forms. This mechanism, however, was not protective because these cells after a 24-h incubation had a several-fold reduced green/red fluorescence ratio compared to the control. Using the checkerboard assay, a synergistic/additive interaction of SER with all four antibiotics tested was demonstrated. These results indicate that SER may be a promising anti-H. pylori compound.

Consequences of PCA graphs, SNP codings, and PCA variants for elucidating population structure

SNP datasets are high-dimensional, often with thousands to millions of SNPs and hundreds to thousands of samples or individuals. Accordingly, PCA graphs are frequently used to provide a low-dimensional visualization in order to display and discover patterns in SNP data from humans, animals, plants, and microbes—especially to elucidate population structure. PCA is not a single method that is always done the same way, but rather requires three choices which we explore as a three-way factorial: two kinds of PCA graphs by three SNP codings by six PCA variants. Our main three recommendations are simple and easily implemented: Use PCA biplots, SNP coding 1 for the rare allele and 0 for the common allele, and double-centered PCA (or AMMI1 if main effects are also of interest). We also document contemporary practices by a literature survey of 125 representative articles that apply PCA to SNP data, find that virtually none implement our recommendations. The ultimate benefit from informed and optimal choices of PCA graph, SNP coding, and PCA variant, is expected to be discovery of more biology, and thereby acceleration of medical, agricultural, and other vital applications.

In vitro synergy of sertraline and tetracycline cannot be reproduced in pigs orally challenged with a tetracycline resistant Escherichia coli

Background

Antimicrobial helper-compounds may reverse antimicrobial resistance. Sertraline, a antidepressant drug, has been suggested as a tetracycline helper-compound. Tetracycline is the preferred antimicrobial for treatment of enteric diseases in pigs. This study is the first to evaluate the potency of sertraline as a tetracycline adjuvant in pigs.

Methods

Forty-eight nursery pigs were divided into four treatment groups: Tetracycline, sertraline, tetracycline/sertraline or un-medicated control. Fecal and ileal samples were obtained before treatment, 48 h and nine days after five days of treatment, respectively. Colony forming units (CFU) of tetracycline resistant coliforms in each sample (ileal or fecal) and CFU of an orally inoculated tetracycline-resistant strain of Escherichia coli were determined at each sampling point. The microbiome of fecal and ileal and samples was analyzed by sequencing of the 16S V3-V4 region.

Results

The results did not provide evidence that sertraline in combination with tetracycline has any impact on tetracycline resistant bacteria in either fecal or ileum samples, while in the tetracycline treated group of pigs, an increase in the prevalence of a tetracycline resistant indicator strain of Escherichia coli shortly after ended five-day treatment was observed. The ileal samples obtained shortly after ended treatment showed treatment-associated changes in the composition of the microbiota in the groups of pigs treated with tetracycline (+/−) sertraline. While tetracycline treatment increased the abundance in the reads of E. coli, sertraline/tetracycline treatment led to increased abundances of Streptococcus spp. and decreased abundances of Lactobacillus spp. However, all observed differences (on CFU counts and microbiota composition) between groups shortly after treatment had diminished in less than two weeks after last treatment day.

Conclusions

Sertraline (+/−) tetracycline treatment did not reduce the long-term level of tetracycline-resistant bacteria in the feces or small intestine contents of piglets compared to the un-medicated control group of pigs. The result of this study reflects the importance of in vivo studies for confirmation of the antimicrobial helper-compound potential of an in vitro active compound.

Electronic supplementary material

The online version of this article (10.1186/s12866-018-1383-5) contains supplementary material, which is available to authorized users.

Treatment with high-dose antidepressants severely exacerbates the pathological outcome of experimental Escherichia coli infections in poultry

There is an urgent need for novel antibiotics as the current antibiotics are losing their value due to increased resistance among clinically important bacteria. Sertraline, an on-marked anti-depressive drug, has been shown to modify bacterial activity in vitro, including increasing the susceptibility of Escherichia coli to antibiotics. The aim of the present study was to investigate if the antimicrobial activity of sertraline could be documented under clinical settings, hereunder if sertraline could potentiate the effect of tetracycline in treatment of an experimentally induced ascending infection in poultry. A total of 40 chickens were divided in four groups of 10 chickens each. All chickens were challenged with 4x10³ colony forming units (CFU) of a tetracycline resistant E. coli strain using a surgical infection model, and subsequently treated with either high-dose sertraline, tetracycline, a combination hereof or received no treatment. Seven days post challenge all birds were submitted to necropsy and scored pathologically for lesions. The average lesion scores were significantly higher (P<0.05) in the groups that were treated with high-dose sertraline or high-dose sertraline combined with tetracycline. In conclusion high-dose treatments (four times the maximum therapeutic dose for treating human depression) with sertraline as an adjuvant for treatment of antibiotic resistant E. coli infections exacerbate the pathological outcome of infection in chickens.