Comparative transcriptomic response analysis of Escherichia coli K-12 MG1655 to nine antibiotics
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ABSTRACT: To investigate and compare transcriptomic changes of Escherichia coli K-12 MG1655, the bacterium was exposed to nine antibiotics (tetracycline, mitomycin C ,imipenem, ceftazidime, kanamycin, ciprofloxacin, polymyxin E, erythromycin, and chloramphenicol) , and RNA-Seq was performed to determine comparative transcriptomic changes.
Project description:We have completed transcriptional profiles of H. pylori cells undergoing DNA damage, caused by either failure to repair endogenous damage (addA- cells) or exposure to ciprofloxacin, which binds DNA gyrase, thus inducing double strand breaks. The goals of this study were to elucidate factors required to sustain the transcription response to DNA damage. All mutants are complete deletions of the coding sequence. The recA and comB10 genes are disrupted with the chloramphenical acetyl transferase (CAT) gene, encoding chloramphenicol resistance. The addA gene is disrupted with the aph3 gene, which encodes resistence to kanamycin. All mutant phenotypes can be complemented by expression of the gene at a heterologous locus.
Project description:We compared the dynamics and mechanisms of resistance development to ceftazidime, meropenem, ciprofloxacin, and ceftolozane-tazobactam in wild-type (PAO1) and mutator (PAOMS, M-bM-^HM-^FmutS) P. aeruginosa. The strains were incubated for 24 h with 0.5 to 64M-CM-^W MICs of each antibiotic in triplicate experiments. The tubes from the highest antibiotic concentration showing growth were reinoculated in fresh medium containing concentrations up to 64M-CM-^W MIC for 7 consecutive days. The susceptibility profiles and resistance mechanisms were assessed in two isolated colonies from each step, antibiotic, and strain. Ceftolozane-tazobactam-resistant mutants were further characterized by whole-genome analysis through RNA sequencing (RNA-seq). The development of high-level resistance was fastest for ceftazidime, followed by meropenem and ciprofloxacin. None of the mutants selected with these antibiotics showed cross-resistance to ceftolozane-tazobactam. On the other hand, ceftolozane-tazobactam resistance development was much slower, and high-level resistance was observed for the mutator strain only. PAO1 derivatives that were moderately resistant (MICs, 4 to 8 ug/ml) to ceftolozane-tazobactam showed only 2 to 4 mutations, which determined global pleiotropic effects associated with a severe fitness cost. High-level-resistant (MICs, 32 to 128 ug/ml) PAOMS derivatives showed 45 to 53 mutations. Major changes in the global gene expression profiles were detected in all mutants, but only PAOMS mutants showed ampC overexpression, which was caused by dacB or ampR mutations. Moreover, all PAOMS mutants contained 1 to 4 mutations in the conserved residues of AmpC (F147L, Q157R, G183D, E247K, or V356I). Complementation studies revealed that these mutations greatly increased ceftolozane-tazobactam and ceftazidime MICs but reduced those of piperacillin-tazobactam and imipenem, compared to those in wild-type ampC. Therefore, the development of high-level resistance to ceftolozane-tazobactam appears to occur efficiently only in a P. aeruginosa mutator background, in which multiple mutations lead to overexpression and structural modifications of AmpC. Mutants of Pseudomonas aeroginosa PAO1 and PAO1 M-bM-^HM-^FmutS against Ceftolozane-tazobactam were generated and analysed using RNA-Seq
Project description:We compared the dynamics and mechanisms of resistance development to ceftazidime, meropenem, ciprofloxacin, and ceftolozane-tazobactam in wild-type (PAO1) and mutator (PAOMS, ∆mutS) P. aeruginosa. The strains were incubated for 24 h with 0.5 to 64× MICs of each antibiotic in triplicate experiments. The tubes from the highest antibiotic concentration showing growth were reinoculated in fresh medium containing concentrations up to 64× MIC for 7 consecutive days. The susceptibility profiles and resistance mechanisms were assessed in two isolated colonies from each step, antibiotic, and strain. Ceftolozane-tazobactam-resistant mutants were further characterized by whole-genome analysis through RNA sequencing (RNA-seq). The development of high-level resistance was fastest for ceftazidime, followed by meropenem and ciprofloxacin. None of the mutants selected with these antibiotics showed cross-resistance to ceftolozane-tazobactam. On the other hand, ceftolozane-tazobactam resistance development was much slower, and high-level resistance was observed for the mutator strain only. PAO1 derivatives that were moderately resistant (MICs, 4 to 8 ug/ml) to ceftolozane-tazobactam showed only 2 to 4 mutations, which determined global pleiotropic effects associated with a severe fitness cost. High-level-resistant (MICs, 32 to 128 ug/ml) PAOMS derivatives showed 45 to 53 mutations. Major changes in the global gene expression profiles were detected in all mutants, but only PAOMS mutants showed ampC overexpression, which was caused by dacB or ampR mutations. Moreover, all PAOMS mutants contained 1 to 4 mutations in the conserved residues of AmpC (F147L, Q157R, G183D, E247K, or V356I). Complementation studies revealed that these mutations greatly increased ceftolozane-tazobactam and ceftazidime MICs but reduced those of piperacillin-tazobactam and imipenem, compared to those in wild-type ampC. Therefore, the development of high-level resistance to ceftolozane-tazobactam appears to occur efficiently only in a P. aeruginosa mutator background, in which multiple mutations lead to overexpression and structural modifications of AmpC.
Project description:Circumventing or overwhelming the bacterial adaptation capabilities is key to combatting multidrug-resistant pathogens like Pseudomonas aeruginosa. We investigated the physiological stress exerted by approved antibiotics (ciprofloxacin, levofloxacin, rifampicin, gentamicin, tobramycin, azithromycin, tigecycline, polymyxin B, colistin, ceftazidime, meropenem, piperacillin/tazobactam), experimental antibiotics (CHIR-090) and NSAIDs (acetylsalicylic acid (aspirin), diclofenac, ibuprofen), and studied the bacterial response on the proteome level. Radioactive pulse-labeling of newly synthesized proteins followed by 2D-PAGE was used to monitor the acute response of P. aeruginosa to antibiotic treatment. Subsequently, marker proteins were excised from non-radioactive gels and identified by mass spectrometry. We generated a reference library of P. aeruginosa proteomic responses and implemented a mathematical comparison of the profiles. Proteomic signatures were derived for clinically relevant target areas.
Project description:RNA sequencing (RNA-seq) of Mycobacterium abscessus in four infection-relevant culture conditions: hypoxic stress, artificial sputum medium, kanamycin-treated medium, and erythromycin-treated medium. Triplicate cultures of M. abscessus were grown in (1) Artificial Sputum media, (2) hypoxic conditions, (3) the presence of kanamycin, and (4) the presence of erythromycin. Triplicate controls were prepared for sample (1) and samples (2-4).
Project description:We report the application of a high-throughput technique, RNA-seq, to study the transcriptomic response of P. putida DOT-T1E in the presence of antibiotics with different mechanisms of action with the aim to study in more detail the defense mechanisms that bacteria use to resist against toxic compounds. We find that P. putida DOT-T1E responde in a different way against each antimicrobial compound, what clearly shows that bacteria defense in different ways depending on the targets that compounds uses to attack. Our work is the first global transcriptomic analysis done in P. putida DOT-T1E in the presence of a considerable range of antibiotics. P. putida DOT-T1E mRNA profiles in the presence of control condition (LB) and 8 different antibiotics (ampicillin, chloramphenicol, kanamycin, ciprofloxacin, tetracycline, spectinomycin, gentamicin and rifampicin)
Project description:Circumventing or overwhelming the bacterial adaptation capabilities is key to combatting multidrug-resistant pathogens like Pseudomonas aeruginosa. In an effort to understand the physiological response of P. aeruginosa to clinically relevant antibiotics, we investigated the proteome after exposure to ciprofloxacin, levofloxacin, rifampicin, gentamicin, tobramycin, azithromycin, tigecycline, polymyxin B, colistin, ceftazidime, meropenem, and piperacillin/tazobactam. We further investigated the response to CHIR-90, which represents a promising class of lipopolysaccharide biosynthesis inhibitors currently under evaluation. Radioactive pulse-labeling of newly synthesized proteins followed by 2D-PAGE was used to monitor the acute response of P. aeruginosa to antibiotic treatment. Marker proteins were excised from non-radioactive gels and identified by mass spectrometry. The proteomic profiles provide insights into the cellular defense strategies for each antibiotic. A mathematical comparison of these response profiles based on upregulated marker proteins revealed similarities of responses to antibiotics acting on the same target area.
Project description:Transcriptional profiling of N. gonorrhoeae comparing wild type cells to cells with inactivated by kanamycin cassette (km) gene involved in restriction modification NgoAXP or with chloramphenicol cassette (cm) gene involved in restriction-modification NgoAV. The Goal was to study the role of M.NgoAXP and NgoAV methyltransferases in overall expression profile.
Project description:Antibiotics in low concentrations may have an array of effects. We have exposed growing P. aeruginosa cells to different classes of antibiotics in order to investigate this hypothesis. We have used DNA microarrays to investigate the effect of low concentrations of antibiotics (azithromycin, ceftazidime and ciprofloxacin) on the gene expression of P. aeruginosa aiming to elucidate general trends. Keywords: Treatment with antibiotics