Resistance phenotypes according to CLSI vs. Statistically significant association between applied guidelines and drug resistance patterns were observed to as follows: ampicillin, cefuroxime, cefotaxime, amoxicillin-clavulanate, azithromycin, tetracycline and trimethoprim-sulfamethoxazole. resistance to beta-lactams were determined. Both susceptibility to various antimicrobials and phenotypes of Haemophilus spp. were identified by colony morphology, Gram-staining, API NH and MALDI-TOF MS technique. parainfluenzae isolates were obtained from throat or nasopharyngeal swabs from adults 18 to 70 years old, both healthy volunteers and patients with chronic diseases between 2013 to 2015 in eastern Poland. Various doubts have already appeared in preliminary stages of microbiological diagnostics of Haemophilus spp. coli.The application of CLSI and EUCAST guidelines led to many discrepancies. To test the generality of PBP3 inhibition on persister formation, we expressed FtsI Ser307Ala to genetically inhibit PBP3, and suppression of persister formation was also observed, although not to the same magnitude as that seen for piperacillin treatment.CONCLUSIONS: From these data we conclude that stationary phase PBP3 activity is important to type I persister formation in E. Previously, PBP3 inhibition had been linked to antibiotic efficacy through the DpiBA two component system however, piperacillin suppressed persister formation in ΔdpiA to the same extent as it did in wild-type, suggesting that DpiBA is not required for the phenomenon reported here. Further analyses showed that piperacillin exposure through stationary phase resulted in cells with more ATP, DNA, RNA, and protein (including PBPs) than untreated controls and that their physiology led to more rapid resumption of DNA gyrase supercoiling activity, translation, and cell division upon introduction into fresh media.
Given the concurrence of these processes, we sought to assess whether perturbation to cell wall synthesis during stationary phase impacts type I persister formation.RESULTS: We tested a panel of cell wall inhibitors and found that piperacillin, which primarily targets penicillin binding protein 3 (PBP3 encoded by ftsI), resulted in a significant reduction in both β-lactam (ampicillin, carbenicillin) and fluoroquinolone (ofloxacin, ciprofloxacin) persister levels. Passage through stationary phase is associated with the formation of persisters (type I), and a major physiological response of Escherichia coli during stationary phase is cell wall restructuring. Stationary phase persister formation in Escherichia coli can be suppressed by piperacillin and PBP3 inhibition.īeta-Lactams, Cell Wall, Drug Resistance, Bacterial, Escherichia coli, Escherichia coli Proteins, Fluoroquinolones, Mutation, Penicillin-Binding Proteins, Peptidoglycan Glycosyltransferase, Phenotype, Piperacillin, Protein Kinases, Transcription FactorsīACKGROUND: Persisters are rare phenotypic variants within a bacterial population that are capable of tolerating lethal antibiotic concentrations.