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Antimicrobial resistance (AMR) is one of the top ten threats to public health, as reported by the World Health Organization (WHO). One of the causes of the growing AMR problem is the lack of new therapies and/or treatment agents; consequently, many infectious diseases could become uncontrollable. The need to discover new antimicrobial agents that are alternatives to the existing ones and that allow mitigating this problem has increased, due to the rapid and global expansion of AMR. Within this context, both antimicrobial peptides (AMPs) and cyclic macromolecules, such as resorcinarenes, have been proposed as alternatives to combat AMR. Resorcinarenes present multiple copies of antibacterial compounds in their structure. These conjugate molecules have exhibited antifungal and antibacterial properties and have also been used in anti-inflammatory, antineoplastic, and cardiovascular therapies, as well as being useful in drug and gene delivery systems. In this study, it was proposed to obtain conjugates that contain four copies of AMP sequences over a resorcinarene core. Specifically, obtaining (peptide) 4 -resorcinarene conjugates derived from LfcinB (20-25): RRWQWR and BF (32-34): RLLR was explored. First, the synthesis routes that allowed obtaining: (a) alkynyl-resorcinarenes and (b) peptides functionalized with the azide group were established. These precursors were used to generate (c) (peptide) 4 -resorcinarene conjugates by azide-alkyne cycloaddition CuAAC, a kind of click chemistry. Finally, the conjugates' biological activity was evaluated: antimicrobial activity against reference strains and clinical isolates of bacteria and fungi, and the cytotoxic activity over erythrocytes, fibroblast, MCF-7, and HeLa cell lines. Our results allowed establishing a new synthetic route, based on click chemistry, for obtaining macromolecules derived from resorcinarenes functionalized with peptides. Moreover, it was possible to identify promising antimicrobial chimeric molecules that may lead to advances in the development of new therapeutic agents.

Objectives: To generate evidence-based recommendations through formal consensus regarding the treatment of upper urinary tract infections during gestation., Materials and Methods: Experts in microbiology, public health, internal medicine, infectious diseases, obstetrics, maternal fetal medicine and obstetric and gynecological infections participated in the consensus development group. The group also included professionals with training in clinical epidemiology, systematic data search, and representatives from the Health Secretariat and the Bogota Obstetrics and Gynecology Association. The participants disclosed their conflicts of interest. Starting with a clinical question, outcomes were graded and a systematic search was conducted in the Medline via PubMed, Embase, Lilacs, and Bireme databases. The search was expanded to include institutional repositories and antimicrobial resistance surveillance systems, with no language or date restrictions. The search was updated on October 1, 2022. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology was used to assess the quality of the evidence and determine the strength of the recommendations. Finally, the RAND/UCLA (Research and Development/University of California Los Angeles) methodology was applied for the formal consensus. This document was reviewed by academic peers before publication., Results: The following are the consensus recommendations. Recommendation 1. The initial management of pregnant women with upper urinary tract infections (UTIs) should be approached in a hospital setting. Recommendation 2. The use of second generation cephalosporins is the suggested first option for empirical antimicrobial management in pregnant women with upper UTI in order to improve the rates of clinical and microbiological cure. Recommendation 3. Because of the risk-benefit balance, the use of aminoglycosides is suggested as a second option for empirical antimicrobial treatment in pregnant women presenting with upper UTIs in the second and third trimester. Recommendation 4. The use of third-generation cephalosporins is suggested as the third option for empirical antimicrobial treatment in pregnant women with upper UTIs given that the risk of inducing microbial resistance is high with this group of antibiotics. Recommendation 5. The use of carbapenems is suggested as a first option in pregnant women with upper UTIs and a history of infections caused by microorganisms with resistance to third or fourth-generation cephalosporins. Recommendation 6. The use of aminoglycosides or fourth-generation cephalosporins is suggested as a second option in pregnant women with upper UTIs and a history of infection caused by microorganisms with resistance to third-generation cephalosporins, taking risk-benefit into account. Recommendation 7. The use of piperacillin/tazobactam is suggested as a third option in pregnant women with upper UTIs and a history of infection caused by microorganisms with resistance to third or fourthgeneration cephalosporins. Recommendation 8. Getting a urine culture is recommended in pregnant women with upper UTIs before initiating empirical antimicrobial treatment. Recommendation 9. In pregnant women with upper UTIs, it is suggested to modify therapy in accordance with the results of the sensitivity test when the culture report shows resistance to the antimicrobial agent initiated empirically. Recommendation 10. In pregnant women hospitalized due to upper UTIs, it is suggested to switch to oral antimicrobial therapy after at least 48 hours of modulation of the systemic inflammatory response and the clinical signs of infection, and when tolerance to oral intake is adequate. Recommendation 11. In pregnant women with upper UTIs with no complications secondary to the primary infection, it is recommended to administer antibiotic therapy for a period of 7 to 10 days., Conclusions: It is expected that with this Colombian upper UTI consensus variability in clinical practice will be reduced. It is recommended that groups doing research in maternal fetal medicine assess the implementation and effectiveness of these recommendations.

Chimeric peptides containing short sequences derived from bovine Lactoferricin (LfcinB) and Buforin II (BFII) were synthetized using solid-phase peptide synthesis (SPPS) and characterized via reversed-phase liquid chromatography and mass spectrometry. The chimeras were obtained with high purity, demonstrating their synthetic viability. The chimeras' antibacterial activity against Gram-positive and Gram-negative strains was evaluated. Our results showed that all the chimeras exhibited greater antibacterial activity against the evaluated strains than the individual sequences, suggesting that chemical binding of short sequences derived from AMPs significantly increased the antibacterial activity. For each strain, the chimera with the best antibacterial activity exerted a bacteriostatic and/or bactericidal effect, which was dependent on the concentration. It was found that: (i) the antibacterial activity of a chimera is mainly influenced by the linked sequences, the palindromic motif RLLRRLLR being the most relevant one; (ii) the inclusion of a spacer between the short sequences did not significantly affect the chimera's synthesis process; however, it enhanced its antibacterial activity against Gram-negative and Gram-positive strains; on the other hand, (iii) the replacement of Arg with Lys in the LfcinB or BFII sequences improved the chimeras' synthesis process without significantly affecting their antibacterial activity. These results illustrate the great importance of the synthesis of chimeric peptides for the generation of promising antibacterial peptides., (© 2020 Wiley-VHCA AG, Zurich, Switzerland.)

Short peptides derived from buforin and lactoferricin B were conjugated with other antimicrobial molecules of different chemical natures. The sequences RLLR, RLLRLLR, RWQWRWQWR, and RRWQWR were conjugated at their N-terminal end with non-peptidic molecules such as 6-aminohexanoic acid, ferrocene, caffeic acid, ferulic acid, and oxolinic acid. Peptide conjugates and unmodified peptides were synthesized by means of solid-phase peptide synthesis using the Fmoc/ t Bu strategy (SPPS-Fmoc/ t Bu), purified via RP-SPE, and characterized via RP-HPLC and MS. The peptides' antibacterial activity against bacterial strains E. coli ATCC 25922 and S. aureus ATCC 25923 was evaluated, and the results showed that the peptide conjugates exhibited higher antibacterial activity than the original unconjugated peptides. Conjugation of AMPs is a promising strategy for designing and identifying new drugs for treating bacterial infections., Competing Interests: The authors declare no conflicts of interest., (This journal is © The Royal Society of Chemistry.)

Dimeric and tetrameric peptides derived from LfcinB (20-25): RRWQWR, LfcinB (20-30): RRWQWRMKKLG, LfcinB (17-31): FKARRWQWRMKKLGA, or the palindromic sequence LfcinB (21-25) Pal : RWQWRWQWR were obtained by means of the SPPS-Fmoc/ t Bu methodology. The antibacterial activity of these molecules was evaluated against Escherichia coli (ATCC 25922 and ATCC 11775), Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), and Pseudomonas aeruginosa (ATCC 27853). The dimer LfcinB (20-25) 2 : (RRWQWR) 2 K-Ahx, the tetramer LfcinB (20-25) 4 : (RRWQWR) 4 K 2 -Ahx 2 -C 2 , and the palindromic sequence LfcinB (21-25) Pal exhibited the highest antibacterial activity against the tested bacterial strains. In all cases, the antibacterial activity was dependent on peptide concentration. The polyvalent molecules LfcinB (20-25) 2 and LfcinB (20-25) 4 exhibited bacteriostatic and bactericidal activity against E. coli , P. aeruginosa , and S. aureus strains; additionally, this dimer and this tetramer combined with ciprofloxacin exhibited a synergistic antibacterial effect against E. coli ATCC 25922 and P. aeruginosa , respectively. Furthermore, the peptides LfcinB (20-30) 4 , LfcinB (20-25) 4 , and LfcinB (21-25) Pal combined with vancomycin exhibited a synergistic antibacterial effect against S. aureus and E. faecalis , respectively. This study showed that polyvalent peptides derived from LfcinB exhibit significant antibacterial activity, suggesting that these peptides could have a therapeutic application. Furthermore, our results suggest that polyvalent peptide synthesis could be considered as an innovative and viable strategy for obtaining promising antimicrobial molecules., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Linear, dimeric, tetrameric, and cyclic peptides derived from lactoferricin B, containing the RRWQWR motif, were designed, synthesized, purified, and characterized using RP-HPLC chromatography and MALDI-TOF mass spectrometry. The antibacterial activity of the designed peptides against E. coli (ATCC 11775 and 25922) and their cytotoxic effect against MDA-MB-468 and MDA-MB-231 breast cancer cell lines were evaluated. Dimeric and tetrameric peptides showed higher antibacterial activity in both bacteria strains than linear peptides. The dimeric peptide (RRWQWR)₂K-Ahx exhibited the highest antibacterial activity against the tested bacterial strains. Furthermore, the peptides with high antibacterial activity exhibited significant cytotoxic effect against the tested breast cancer cell lines. This cytotoxic effect was fast and dependent on the peptide concentration. The tetrameric molecule containing RRWQWR motif has an optimal cytotoxic effect at a concentration of 22 µM. The evaluated dimeric and tetrameric peptides could be considered as candidates for developing new therapeutic agents against breast cancer. Polyvalence of linear sequences could be considered as a novel and versatile strategy for obtaining molecules with high anticancer activity., Competing Interests: The authors declare no conflict of interest.

Objective: Describe and compare the frequency of bacterial resistance phenotypes of microorganisms obtained from patients in intensive care units (ICU) and other (non-ICU) high-complexity public and private hospital services in Colombia., Methods: A retrospective observational, analytical, multicenter study was conducted. The records from January 2007 to December 2009 on bacterial isolates and bacterial resistance phenotypes of microorganisms obtained from ICU and non-ICU patients in 79 high-complexity public and private hospitals were consolidated. The information was analyzed with the WHONET(®) 5.5 (WHO) software, following the 2009 recommendations of the Clinical and Laboratory Standards Institute, and summarized on an Excel(®) spreadsheet. A descriptive analysis with the calculation of proportions was performed. The trends were analyzed with Spearman rank correlation., Results: The 2007-2009 trends for bacterial resistance phenotypes show increased percentages of vancomycin-resistant Enterococcus faecium, imipenem-resistant Klebsiella pneumoniae, ciprofloxacin-resistant K. pneumoniae, ceftazidime-resistant Escherichia coli and cefotaxime-resistant Enterobacter cloacae (r = 1, P < 0.01), and reduced percentages of ciprofloxacin-resistant E. coli, ceftazidime-resistant K. pneumoniae, oxacillin-resistant Staphylococcus aureus, ceftazidime-resistant Pseudomonas aeruginosa, and ciprofloxacin-resistant P. aeruginosa (r = -1, P < 0.01)., Conclusions: The trend analysis presented in this study is the baseline for establishing a national epidemiological surveillance subsystem. The trends observed reveal that bacterial resistance to antimicrobial drugs in hospitals in Colombia is a dynamic phenomenon, with evidence of the emergence of vancomycin-resistant E. faecium and imipenem-resistant K. pneumoniae phenotypes in the hospitals.