Ciprofloxacin Treatment Research Articles

Ciprofloxacin Causes the Greatest Bacterial Community Variation in Swine Manure Composting

In this study, the influence of ciprofloxacin, chlorotetracycline, lincomycin, and sulfamethoxazole on the composition of the bacterial community structure was studied during aerobic composting with swine manure. Firmicutes (26.67%) and Chloroflexi (23.33%) were the most widely distributed phyla. Under all antibiotic treatments, the relative abundances of Bacillaceae, Streptosporangiaceae, Limnochordaceae, and Peptostreptococcaceae increased during the composting process. Moreover, norank_SBR1031, Planococcaceae, Thermomonosporaceae, Peptostreptococcaceae, Erysipelotrichaceae, Limnochordaceae, and Clostridiaceae_1 were the families showing the most significant differences across all treatments (p < 0.05). Principal co-ordinates analysis indicated that the family composition in the ciprofloxacin treatment significantly differed from the other treatments. The presence of ciprofloxacin increased both the abundance and diversity of the bacterial community (the Chao index changed from 588.44 to 680.17, and the Shannon index changed from 3.41 to 4.06) in the end of composting. Crocinitomicaceae dominated (relative abundance of 79.10%) among the unique families in the ciprofloxacin treatment. Network analysis indicated that ciprofloxacin altered the synergistic or competitive relationships between different families (norank_SBR1031 and Microscillaceae), leading to different bacterial community composition compared with other treatments. Further, a structural equation model showed that the C:N ratio was significantly negatively correlated with the bacterial community (λ = −0.869, p < 0.01), whereas pH showed a direct, significant positive relationship with the bacterial community (λ = 0.701, p < 0.01), especially in ciprofloxacin treatment. Overall, ciprofloxacin significantly influenced the physical and chemical properties of composting, altered the bacterial community structure. These findings have important implications for a better understanding of the effects of antibiotic types on bacterial community structure and the involved mechanisms during swine manure composting.

Adjunctive Thymosin Beta-4 Treatment Influences PMN Effector Cell Function during Pseudomonas aeruginosa-Induced Corneal Infection.

Previous work examining the therapeutic efficacy of adjunct thymosin beta 4 (Tβ4) to ciprofloxacin for ocular infectious disease has revealed markedly reduced inflammation (inflammatory mediators and innate immune cells) with increased activation of wound healing pathways. Understanding the therapeutic mechanisms of action have further revealed a synergistic effect with ciprofloxacin to enhance bacterial killing along with a regulatory influence over macrophage effector cell function. As a natural extension of the aforementioned work, the current study uses an experimental model of P. aeruginosa-induced keratitis to examine the influence of Tβ4 regarding polymorphonuclear leukocyte (PMN/neutrophil) cellular function, contributing to improved disease response. Flow cytometry was utilized to phenotypically profile infiltrating PMNs after infection. The generation of reactive oxygen species (ROS), neutrophil extracellular traps (NETs), and PMN apoptosis were investigated to assess the functional activities of PMNs in response to Tβ4 therapy. In vitro work using peritoneal-derived PMNs was similarly carried out to verify and extend our in vivo findings. The results indicate that the numbers of infiltrated PMNs into infected corneas were significantly reduced with adjunctive Tβ4 treatment. This was paired with the downregulated expression of proinflammatory markers on these cells, as well. Data generated from PMN functional studies suggested that the corneas of adjunctive Tβ4 treated B6 mice exhibit a well-regulated production of ROS, NETs, and limited PMN apoptosis. In addition to confirming the in vivo results, the in vitro findings also demonstrated that neutrophil elastase (NE) was unnecessary for NETosis. Collectively, these data provide additional evidence that adjunctive Tβ4 + ciprofloxacin treatment is a promising option for bacterial keratitis that addresses both the infectious pathogen and cellular-mediated immune response, as revealed by the current study.

Effects of fluoroquinolones and tetracyclines on mitochondria of human retinal MIO-M1 cells

Our goal was to explore the detrimental impacts of ciprofloxacin (CPFX) and tetracycline (TETRA) on human retinal Müller (MIO-M1) cells in vitro. Cells were exposed to 30, 60 and 120 μg/ml of CPFX and TETRA. The cellular metabolism was measured with the MTT assay. The JC-1 and CM-H2DCFDA assays were used to evaluate the levels of mitochondrial membrane potential (MMP) and ROS (reactive oxygen species), respectively. Mitochondrial DNA (mtDNA) copy number, along with gene expression levels associated with apoptotic (BAX, BCL2-L13, BCL2, CASP-3 and CASP-9), inflammatory (IL-6, IL-1β, TGF-α, TGF-β1 and TGF-β2) and antioxidant pathways (SOD2, SOD3, GPX3 and NOX4) were analyzed via Quantitative Real-Time PCR (qRT-PCR). Bioenergetic profiles were measured using the Seahorse® XF Flux Analyzer. Cells exposed 24 h to 120 μg/ml TETRA demonstrated higher cellular metabolism compared to vehicle-treated cells. At each time points, (i) all TETRA concentrations reduced MMP levels and (ii) ROS levels were reduced by TETRA 120 μg/ml treatment. TETRA caused (i) higher expression of CASP-3, CASP-9, TGF-α, IL-1B, GPX3 and SOD3 but (ii) decreased levels of TGF-B2 and SOD2. ATP production and spare respiratory capacity declined with TETRA treatment. Cellular metabolism was reduced with CPFX 120 μg/ml in all cultures and 60 μg/ml after 72 h. The CPFX 120 μg/ml reduced MMP in all cultures and ROS levels (72 h). CPFX treatment (i) increased expression of CASP-3, CASP-9, and BCL2-L13, (ii) elevated the basal oxygen consumption rate, and (iii) lowered the mtDNA copy numbers and expression levels of TGF-B2, IL-6 and IL-1B compared to vehicle-control cells. We conclude that clinically relevant dosages of bactericidal and bacteriostatic antibiotics can have negative effects on the cellular metabolism and mitochondrial membrane potential of the retinal MIO-M1 cells in vitro. It is noteworthy to mention that apoptotic and inflammatory pathways in exposed cells were affected significantly This is the first study showing the negative impact of fluoroquinolones and tetracyclines on mitochondrial behavior of human retinal MIO-M1 cells.

Ciprofloxacin stress changes key enzymes and intracellular metabolites of Lactobacillus plantarum DNZ-4

Ciprofloxacin (CIP) is an antibiotic used to treat infections caused by bacteria. In this experiment, key enzymes and intracellular metabolites of Lactobacillus plantarum DNZ-4 was researched under CIP stress. The results showed that the activities of hexokinase, pyruvate kinase, β-galactosidase and Na+, K+-ATPase after 1/2 minimum bacteriostatic concentration (MIC) CIP treatment were significantly decreased (P<0.01). Gas chromatography-mass spectrometry was used to analysis the changes of main metabolites in the cells and principal component analysis and partial least square model were constructed. The results indicated that CIP could cause changes in intracellular fatty acids, carbohydrates and amino acids, and the mechanism of amino acid metabolism under CIP stress was significantly inhibited. L. plantarum DNZ-4 made stress response to CIP by regulating the ratio of saturated fatty acids and unsaturated fats. This experiment revealed the changes of growth and metabolism mechanism of L. plantarum DNZ-4 under CIP stress, which help to provide technical means for the development of effective probiotics preparation products.

Assessing the efficacy of antibiotic treatment to produce earthworms with a suppressed microbiome

Earthworms are an integral part of soil ecosystems, especially for their role in soil functions such as organic matter (OM) decomposition and nutrient cycling. Earthworms and microorganisms are interdependent, and a considerable portion of the contribution earthworms make to influencing OM fate is through interactions with microorganisms. However, the importance of the earthworm-associated microbiome is not fully understood, because it is difficult to separate the direct influence of the earthworms from the indirect influence of their microbiome. Here, we evaluated an antibiotic-based procedure to suppress the microbiome of individuals of ecologically-contrasting earthworm species (Eisenia fetida, Lumbricus terrestris, Allolobophora chlorotica) as the first step towards soil studies aimed at understanding the importance of the earthworm microbiome for host health and function. Individual earthworms were exposed to antibiotics: cycloheximide (150 μg ml−1), ampicillin (100 μg ml−1), ciprofloxacin (50 μg ml−1), nalidixic acid (50 μg ml−1), and gentamicin (50 μg ml−1) either singly or in a cocktail via culture (96 h) in a semi-solid agar carrier. Compared to the non-antibiotic treated control, the cocktail (for all three species) and ciprofloxacin (for E. fetida and A. chlorotica) treatments significantly reduced (P < 0.05) culturable microbial abundance on nutrient agar and potato dextrose agar. The microbial counts were reduced to below detection (<50 CFU individual−1) for E. fetida and A. chlorotica receiving the cocktail. Illumina 16S rDNA amplicon sequence analysis of culturable L. terrestris -associated bacteria showed that antibiotic treatment influenced community composition revealing putative sensitive (Comomonas, Kosakonia and Sphingobacterium) and insensitive (Aeromonas, Pseudochrobactrum) taxa. Overall, we report a rapid, with minimal earthworm-handling, process of creating suppressed-microbiome E. fetida, A. chlorotica and L. terrestris as a tool to be used in future ecological studies of earthworm microbial interactions affecting host health and function.

Existence of log-phase Escherichia coli persisters and lasting memory of a starvation pulse.

The vast majority of a bacterial population is killed when treated with a lethal concentration of antibiotics. The time scale of this killing is often comparable with the bacterial generation time before the addition of antibiotics. Yet, a small subpopulation typically survives for an extended period. However, the long-term killing dynamics of bacterial cells has not been fully quantified even in well-controlled laboratory conditions. We constructed a week-long killing assay and followed the survival fraction of Escherichia coli K12 exposed to a high concentration of ciprofloxacin. We found that long-term survivors were formed during exponential growth, with some cells surviving at least 7 d. The long-term dynamics contained at least three time scales, which greatly enhances predictions of the population survival time compared with the biphasic extrapolation from the short-term behavior. Furthermore, we observed a long memory effect of a brief starvation pulse, which was dependent on the (p)ppGpp synthase relA Specifically, 1 h of carbon starvation before antibiotics exposure increased the surviving fraction by nearly 100-fold even after 4 d of ciprofloxacin treatment.

Gut-Kidney Axis on Chip for Studying Effects of Antibiotics on Risk of Hemolytic Uremic Syndrome by Shiga Toxin-Producing Escherichia coli.

Shiga toxin-producing Escherichia coli (STEC) infects humans by colonizing the large intestine, and causes kidney damage by secreting Shiga toxins (Stxs). The increased secretion of Shiga toxin 2 (Stx2) by some antibiotics, such as ciprofloxacin (CIP), increases the risk of hemolytic–uremic syndrome (HUS), which can be life-threatening. However, previous studies evaluating this relationship have been conflicting, owing to the low frequency of EHEC infection, very small number of patients, and lack of an appropriate animal model. In this study, we developed gut–kidney axis (GKA) on chip for co-culturing gut (Caco-2) and kidney (HKC-8) cells, and observed both STEC O157:H7 (O157) infection and Stx intoxication in the gut and kidney cells on the chip, respectively. Without any antibiotic treatment, O157 killed both gut and kidney cells in GKA on the chip. CIP treatment reduced O157 infection in the gut cells, but increased Stx2-induced damage in the kidney cells, whereas the gentamycin treatment reduced both O157 infection in the gut cells and Stx2-induced damage in the kidney cells. This is the first report to recapitulate a clinically relevant situation, i.e., that CIP treatment causes more damage than gentamicin treatment. These results suggest that GKA on chip is very useful for simultaneous observation of O157 infections and Stx2 poisoning in gut and kidney cells, making it suitable for studying the effects of antibiotics on the risk of HUS.

An in Vitro Study of Molecular Effects of a Combination Treatment with Antibiotics and Nanofluid Containing Carbon Nano-tubes on Klebsiella pneumoniae.

Background:We aimed to prepare a nanofluid, containing f-MWCNTs, and investigate the antibacterial efficacy of f-MWCNTs+ ciprofloxacin (cip) on Klebsiella pneumoniae by evaluating the virulence gene expression.Methods:This study was carried out from 2019 to 2020, in the Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran. The nanofluid containing antibiotic and f-MWCNTs were prepared by the ultrasonic method. The minimum inhibitory concentrations (MICs) of ciprofloxacin and f-MWCNTs were determined using the broth micro dilution MIC tests. For examining the antibacterial effects, the expression level of virulence genes, under the influence of f-MWCNTs, was evaluated by a real-time PCR.Results:The effect of 8 μg/ml ciprofloxacin + 400 μg/ml f-MWCNTs, completely inhibited the growth of the resistant isolate of K. pneumoniae, while, in the ATCC 700,603 isolate, 2 μg/ml ciprofloxacin with 100 μg/ml f-MWCNT could inhibit a bacterial growth. In the resistant K. pneumoniae clinical isolate, after f-MWCNT+cip treatment, the expression of fimA, fimD, wza, and wzi genes was significantly downregulated, compared to the ciprofloxacin treatment, and upregulated, compared to the negative control. For the ATCC 700,603 isolate treated with f-MWCNT+cip, the expression of fimA, fimD and wza virulence genes showed upregulation, compared to the negative control and downregulated in comparison with the ciprofloxacin treatment.Conclusion:Simultaneous treatment of resistant isolate of K. pneumoniae with f-MWCNTs +antibiotic could improve the effectiveness of antibiotic at lower doses, due to the reduced expression of virulence genes in comparison with antibiotic treatment, besides the increased cell wall permeability to antibiotics.

Adjunctive Thymosin Beta-4 Treatment Influences MΦ Effector Cell Function to Improve Disease Outcome in Pseudomonas aeruginosa-Induced Keratitis.

Our previous work has shown that topical thymosin beta 4 (Tβ4) as an adjunct to ciprofloxacin treatment reduces inflammatory mediators and inflammatory cell infiltrates (neutrophils/PMN and macrophages/MΦ) while enhancing bacterial killing and wound healing pathway activation in an experimental model of P. aeruginosa-induced keratitis. This study aimed to mechanistically examine how Tβ4 influences MΦ function in particular, leading to reduced inflammation and enhanced host defense following P. aeruginosa-induced infection of the cornea. Flow cytometry was conducted to profile the phenotype of infiltrating MΦ after infection, while generation of reactive nitrogen species and markers of efferocytosis were detected to assess functional activity. In vitro studies were performed utilizing RAW 264.7 cells to verify and extend the in vivo findings. Tβ4 treatment decreases MΦ infiltration and regulates the activation state in response to infected corneas. MΦ functional data demonstrated that the adjunctive Tβ4 treatment group significantly downregulated reactive nitrogen species (RNS) production and efferocytotic activity. In addition, the in vitro studies showed that both Tβ4 alone and adjunctive Tβ4 treatment influenced MΦ cellular function following LPS stimulation. Collectively, these data provide further evidence that adjunctive Tβ4 + ciprofloxacin treatment offers a more efficacious option for treating bacterial keratitis. Not only does the adjunctive therapy address both the infectious pathogen and corneal wound healing response, but it also influences MΦ infiltration, activation, and function, as revealed by the current study.

Investigation of the effects of three different generations of fluoroquinolone derivatives on antioxidant and immunotoxic enzyme levels in different rat tissues

Fluoroquinolones (FQs) are synthetic and broad-spectrum antimicrobial drugs derived from nalidixic acid. FQs are used against SARS-CoV-2 in our country, and for the treatment of some urinary tract diseases, gastrointestinal diseases, respiratory tract diseases, sexually transmitted diseases, and dermatological diseases. The present study investigated the effect of 1-,7-,14-day treatments of three different FQ derivatives; ciprofloxacin (CIP) 80 mg/kg/day, levofloxacin (LVX) 40 mg/kg/day, and moxifloxacin (MXF) 40 mg/kg/day, on biochemical parameters, lipid peroxidation, antioxidant enzymes, and immunotoxicity. 72 Wistar albino male rats were distributed to four groups including 18 rats in each group and were sacrificed on three different time points. The 14-day treatment of MXF significantly reduced the levels of aspartate aminotransferase (AST), glucose, reduced glutathione (GSH), malondialdehyde (MDA), catalase (CAT), myeloperoxidase (MPO), adenosine deaminase (ADA), and glutathione peroxidase (GPx). Furthermore, 14-day treatment of LVX increased liver [GSH, MPO, ADA, superoxide dismutase (SOD)], and GSH (erythrocyte) levels; whereas it significantly reduced the levels of AST, TG (triglycerides) and associated parameters levels in all the tissues (MDA), erythrocytes, and liver (MPO, CAT, SOD, GPx). After 14-day treatment of CIP; the erythrocyte levels of GSH, MPO, GPx, and CAT significantly decreased; whereas the levels of glucose, creatinine, MPO (liver), and GST (kidney and erythrocyte) significantly increased. It has been concluded that FQ derivatives used in this experiment did not display any correlation in terms of the efficacies in the different time points and tissues. Thus, it is recommended to use such FQ derivatives considering the duration of use and target tissue.

Reversal of Polymicrobial Biofilm Tolerance to Ciprofloxacin by Blue Light plus Carvacrol.

Chronic wound infections are often caused by multi-species biofilms and these biofilm-embedded bacteria exhibit remarkable tolerance to existing antibiotics, which presents huge challenges to control such infections in the wounds. In this investigation, we established a polymicrobial biofilm composed of P. aeruginosa, S. aureus, K. pneumoniae, and A. baumannii. We tested a cocktail therapy comprising 405-nm blue light (BL), carvacrol (Ca), and antibiotics on the multispecies biofilm. Despite the fact that all strains used to form the biofilm were susceptible to ciprofloxacin (CIP) in planktonic cultures, the biofilm was found to withstand ciprofloxacin as well as BL-Ca dual treatment, mainly because K. pneumoniae outgrew and became dominant in the biofilm after each treatment. Strikingly, when ciprofloxacin was combined with BL-Ca, the multispecies biofilms succumbed substantially and were eradicated at an efficacy of 99.9%. Mechanistically, BL-Ca treatment increased membrane permeability and potentiated the anti-biofilm activity of ciprofloxacin, probably by facilitating ciprofloxacin’s entrance of the bacteria, which is particularly significant for K. pneumoniae, a species that is refractory to either ciprofloxacin or BL-Ca dual treatment. The results suggest that bacterial membrane damage can be one of the pivotal strategies to subvert biofilm tolerance and combat the recalcitrant multispecies biofilms.

A Novel Non-Coding RNA CsiR Regulates the Ciprofloxacin Resistance in Proteus vulgaris by Interacting with emrB mRNA.

Bacterial non-coding RNAs (ncRNAs) play important regulatory roles in various physiological metabolic pathways. In this study, a novel ncRNA CsiR (ciprofloxacin stress-induced ncRNA) involved in the regulation of ciprofloxacin resistance in the foodborne multidrug-resistant Proteus vulgaris (P. vulgaris) strain P3M was identified. The survival rate of the CsiR-deficient strain was higher than that of the wild-type strain P3M under the ciprofloxacin treatment condition, indicating that CsiR played a negative regulatory role, and its target gene emrB was identified through further target prediction, quantitative real-time PCR (qRT-PCR), and microscale thermophoresis (MST). Further studies showed that the interaction between CsiR and emrB mRNA affected the stability of the latter at the post-transcriptional level to a large degree, and ultimately affected the ciprofloxacin resistance of P3M. Notably, the base-pairing sites between CsiR and emrB mRNAs were highly conserved in other sequenced P. vulgaris strains, suggesting that this regulatory mechanism may be ubiquitous in this species. To the best of our knowledge, this is the first identification of a novel ncRNA involved in the regulation of ciprofloxacin resistance in P. vulgaris species, which lays a solid foundation for comprehensively expounding the antibiotic resistance mechanism of P. vulgaris.

Pneumonia caused by Pseudomonas fluorescens: a case report

BackgroundPseudomonas fluorescens (P. fluorescens) has been detected in respiratory samples from patients. However, no previous reports have been published about these P. fluorescens cultures from lung tissues.Case presentationHere, we report a case of pneumonia caused by P. fluorescens. P. fluorescens was identified from lung biopsy specimens for the first time in this case. According to the antibiotic susceptibility testing (AST) of P. fluorescens, the patient was given ciprofloxacin treatment. The temperature of the patient then returned to normal. Chest CT examination revealed improvements in pulmonary inflammation.ConclusionsThese findings suggest that the patients with pneumonia caused by P. fluorescens should be treated in a timely manner according to the AST results.

Integrated Metagenomic and Transcriptomic Analyses Reveal the Dietary Dependent Recovery of Host Metabolism From Antibiotic Exposure.

The balance of gut microbiome is essential for maintaining host metabolism homeostasis. Despite widespread antibiotic use, the potential long-term detrimental consequences of antibiotics for host health are getting more and more attention. However, it remains unclear whether diet affects the post-antibiotic recovery of gut microbiome and host metabolism. In this study, through metagenomic sequencing and hepatic transcriptome analysis, we investigated the divergent impacts of short-term vancomycin (Vac), or combination of ciprofloxacin and metronidazole (CM) treatment on gut microbiome and host metabolism, as well as their recovery extent from antibiotic exposure on chow diet (CD) and high-fat diet (HFD). Our results showed that short-term Vac intervention affected insulin signaling, while CM induced more functional changes in the microbiome. However, Vac-induced long-term (45 days) changes of species were more apparent when recovered on CD than HFD. The effects of antibiotic intervention on host metabolism were long-lasting, antibiotic-specific, and diet-dependent. The number of differentially expressed gene was doubled by Vac than CM, but was comparable after recovery on CD as revealed by the hepatic transcriptomic analysis. In contrast, HFD intake during recovery could worsen the extent of post-antibiotic recovery by altering infection, immunity, and cancer-related pathways in short-term Vac-exposed rats and by shifting endocrine system-associated pathways in CM-exposed rats. Together, the presented data demonstrated the long-term recovery extent after different antibiotic exposure was diet-related, highlighting the importance of dietary management during post-antibiotic recovery.

Effect of a diet containing a mixture of soybean isoflavones and soyasaponins on contact hypersensitivity and gut microbiota in mice

AbstractDietary soybean isoflavones (SIs) and soyasaponins (SSs) individually exert inhibitory effects on contact hypersensitivity (CHS), which is an animal model of allergic contact dermatitis (ACD); however, the beneficial effects of diets containing a mixture of SIs and SSs on CHS remain unclear. Here, we investigated the CHS‐suppressive effects of diets containing a mixture of SIs and SSs at physiologically relevant doses, and the role of the gut microbiota. The diets attenuated ear swelling and reduced the number of Gr‐1‐positive cells infiltrating the auricle tissues. Ear swelling was inhibited in the SI‐ and SS‐treated mice compared to the SI‐treated mice. Compared to the CHS controls, the levels of chemokine (C‐X‐C motif) ligand 2 and triggering receptor expressed on myeloid cells‐1 (TREM‐1) were lower in the auricle tissues of SI‐ and SS‐treated mice, whereas TREM‐1 production was not suppressed in SI‐ or SS‐treated mice. In addition, vancomycin treatment had little effect on the CHS‐inhibitory activity of SI and SS diets, whereas ciprofloxacin and metronidazole treatments blocked the effects of SI and SS diets. These antibiotics exhibited differing effects on the microbiota composition deduced from the bacterial 16S ribosomal RNA gene sequences. Therefore, consuming a mixture of SIs and SSs has ACD‐preventive effects and is affected by the gut microbiota.

P038 Microbial regulation of T-cell fate towards regulatory profiles during T-cell transfer induced colitis

Abstract Background During Inflammatory Bowel Diseases (IBD), CD4+ effector T cells are main mediators of the tissue damage. Among them, Th17 cells strongly contribute to the inflammatory response. Interestingly, our lab previously showed that Th17 cells can convert into regulatory T cells, thereby controlling inflammation. However, the forces controlling the plasticity of T cells during IBD remain largely unknown. Our aim is to understand, how CD4+ T-cell plasticity can be modulated from a pro-inflammatory towards an anti-inflammatory profile during IBD. It is currently known that both Th17 and Foxp3 Treg cells can recognize microbiota-derived antigens and that changes in the microbiota are commonly observed in IBD. We hypothesize that the microbiota is a key candidate to modulate T-cell plasticity. Methods T-cell transfer mouse IBD model was performed by transferring CD4+ naïve T-cells into Rag1 -/- receptors. To study Th17 T-cell plasticity, we used as donors IL-17A Fate-mapping mice. These mice comprise of an IL-17ACRE/R26fl/fl YFP construct where the cells that previously expressed IL-17A turn into YFP+ cells. Ciprofloxacin and metronidazole, two antibiotics commonly given to IBD patients, were used to treat the mice. Stool microbiota composition was analysed longitudinally by 16S rRNA amplicon sequencing. Colitis development was evaluated by colonoscopy. CD4+ T cells were isolated from the colon and reporter expression was analysed by Flow Cytometry. Results After T-cell transfer colitis induction, ciprofloxacin and metronidazole treatment alleviated gut inflammation, as determined by weight loss (p=0.005), colitis score (p=0.004) and colon length (p=0.01). Antibiotic treatment increased the relative abundance of bacteria previously associated with beneficial IBD outcomes (e.g. Bifidobacterium). Interestingly, colonic CD4+ T-cells showed an increased conversion from Th17 towards a Foxp3+ Treg profile (Foxp3ExTh17) (p=0.03). Conclusion The conversion of CD4+ effector T cells into Treg cells is a promising approach to counteract inflammation in IBD patients. We showed that antibiotic treatment not only correlates with a relative expansion of beneficial bacteria, but perhaps most interesting, with an increased conversion of effector Th17 cells towards Foxp3+ Treg cells in the colon. Altogether, these data support the manipulation of the microbiota as a tool to revert intestinal inflammation in IBD patients.

Azithromycin and Ciprofloxacin Treatment Outcomes During an Outbreak of Multidrug-Resistant Shigella sonnei Infections in a Retirement Community-Vermont, 2018.

In 2018, the Centers for Disease Control and Prevention and the Vermont Department of Health investigated an outbreak of multidrug-resistant Shigella sonnei infections in a retirement community that offered a continuum of care from independent living through skilled nursing care. The investigation identified 24 culture-confirmed cases. Isolates were resistant to trimethoprim-sulfamethoxazole, ampicillin, and ceftriaxone, and had decreased susceptibility to azithromycin and ciprofloxacin. To evaluate clinical and microbiologic response, we reviewed inpatient and outpatient medical records for treatment outcomes among the 24 patients with culture-confirmed S. sonnei infection. We defined clinical failure as diarrhea (≥3 loose stools per day) for ≥1 day after treatment finished, and microbiologic failure as a stool culture that yielded S. sonnei after treatment finished. We used broth microdilution to perform antimicrobial susceptibility testing, and whole genome sequencing to identify resistance mechanisms. Isolates contained macrolide resistance genes mph(A) and erm(B) and had azithromycin minimum inhibitory concentrations above the Clinical and Laboratory Standards Institute epidemiological cutoff value of ≤16 µg/mL. Among 24 patients with culture-confirmed Shigella infection, 4 were treated with azithromycin; all had clinical treatment failure and 2 also had microbiologic treatment failure. Isolates were susceptible to ciprofloxacin but contained a gyrA mutation; 2 patients failed treatment with ciprofloxacin. These azithromycin treatment failures demonstrate the importance of clinical breakpoints to aid clinicians in identifying alternative treatment options for resistant strains. Additionally, these treatment failures highlight a need for comprehensive susceptibility testing and systematic outcome studies, particularly given the emergence of multidrug-resistant Shigella among an expanding range of patient populations.

Indole Inhibits IncP-1 Conjugation System Mainly Through Promoting korA and korB Expression.

Indole works as an interspecies signal molecule to regulate multiple physiological activities, like antibiotic resistance, acid resistance, and virulence. However, the effect of indole on conjugation is unknown. Here, with Escherichia coli SM10λπ as a donor strain that carries a chromosomally integrated conjugative RP4 plasmid, we explored the effect of indole on conjugation of a mobilizable pUCP24T plasmid imparting gentamycin resistance. The results showed that exogenous indole treatment inhibited conjugative transfer of pUCP24T from SM10λπ to recipient strains, Pseudomonas aeruginosa PAO1 and E. coli EC600. Furthermore, raising endogenous indole production through overexpression of TnaA, a tryptophanase, in SM10λπ significantly inhibited both SM10λπ-PAO1 and SM10λπ-EC600 conjugation, whereas deficiency of tnaA reversed the phenotype. Subsequent mechanistic studies revealed that exogenous indole significantly inhibited the expression of mating pair formation gene (trbB) and the DNA transfer and replication gene (trfA), mainly due to the promotion of regulatory genes (korA and korB), and the result was confirmed in tnaA knockout and overexpression strains. Additionally, we found that both extracellular indole production and tnaA expression of SM10λπ were downregulated by ciprofloxacin (CIP). Intriguingly, one-eighth minimum inhibitory concentration of CIP treatment clearly facilitated both SM10λπ-PAO1 and SM10λπ-EC600 conjugation, and indole inhibited CIP-induced conjugation frequency. These data suggest that indole may play a negative role in the process of CIP-induced conjugation. This is the first study to reveal the biological function of indole-inhibiting conjugation and its role in CIP-induced conjugation, which may be developed into a new way of controlling the spread of antibiotic resistance.

The influence of antibiotics on transitory resistome during gut colonization with CTX-M-15 and OXA-162 producing Klebsiella pneumoniae ST15

Great efforts have been made to limit the transmission of carbapenemase-producing Enterobacteriaceae (CPE), however, the intestinal reservoir of these strains and its modulation by various antibiotics remain largely unexplored. Our aim was to assess the effects of antibiotic administration (ampicillin, ceftazidime, ciprofloxacin) on the establishment and elimination of intestinal colonization with a CTX-M-15 ESBL and OXA-162 carbapenemase producing Klebsiella pneumoniae ST15 (KP5825) in a murine (C57BL/6 male mice) model. Whole genome sequencing of KP5825 strain was performed on an Illumina MiSeq platform. Conjugation assays were carried out by broth mating method. In colonization experiments, 5 × 106 CFU of KP5825 was administered to the animals by orogastric gavage, and antibiotics were administered in their drinking water for two weeks and were changed every day. The gut colonization rates with KP5825 were assessed by cultivation and qPCR. In each of the stool samples, the gene copy number of blaOXA-162 and blaCTX-M-15 were determined by qPCR. Antibiotic concentrations in the stool were determined by high pressure liquid chromatography and a bioanalytical method. The KP5825 contained four different plasmid replicon types, namely IncFII(K), IncL, IncFIB and ColpVC. IncL (containing the blaOXA-162 resistance gene within a Tn1991.2 genetic element) and IncFII(K) (containing the blaCTX-M-15 resistance gene) plasmids were successfully conjugated. During ampicillin and ceftazidime treatments, colonization rate of KP5825 increased, while, ciprofloxacin treatments in both concentrations (0.1 g/L and 0.5 g/L) led to significantly decreased colonization rates. The gene copy number blaOXA-162 correlated with K. pneumoniae in vivo, while a major elevation was observed in the copy number of blaCTX-M-15 from the first day to the fifteenth day in the 0.5 g/L dose ceftazidime treatment group. Our results demonstrate that commonly used antibiotics may have diverse impacts on the colonization rates of intestinally-carried CPE, in addition to affecting the gene copy number of their resistance genes, thus facilitating their stable persistance and dissemination.

Abatement of the dysfunctional hypothalamic-pituitary-gonadal axis due to ciprofloxacin administration by selenium in male rats.

The present study examined the influence of selenium on ciprofloxacin-mediated reproductive dysfunction in rats. The research design consisted of five groups of eight animals each. The rats were administered 135 mg/kg body weight of ciprofloxacin per se or simultaneously with selenium at 0.25 and 0.5 mg/kg for 15 uninterrupted days. Antioxidant and inflammatory indices were assayed using the testes, epididymis, and hypothalamus of the animals after sacrifice. Results revealed that ciprofloxacin treatment per se interfered with the reproductive axis as demonstrated by diminished serum hormonal levels, sperm quality, and enzymatic indices of testicular function, which were, however, abrogated following selenium co-treatment. Besides this, administration of selenium attenuated the depletion of glutathione level, inhibition of catalase, superoxide dismutase, glutathione-S-transferase and glutathione peroxidase activities with a concomitant reduction in reactive oxygen and nitrogen species, and lipid peroxidation in ciprofloxacin-treated in rats. Selenium treatment also mitigated ciprofloxacin-mediated elevation in nitric oxide level and of myeloperoxidase activity as well as histological lesions in the animals. Overall, selenium attenuated impairment in the male reproductive axis due to ciprofloxacin treatment through abatement of inflammation and oxidative stress in rats.