RESUMEN

We evaluated the performance of Zybio EXS2600 matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) (Zybio Inc., Chongqing, China) for the identification of bacteria from positive blood culture (BC) bottles using Blood Culture Positive Sample Pretreatment Kit (Zybio Inc., Chongqing, China) in comparison to an in-house saponin method. Following a positive signal by the BACTEC™ FX system, confirmation of identification was achieved using subcultured growing biomass used for MALDI-TOF MS analysis. A total of 94 positive BC bottles with 97 bacterial isolates were analyzed. The overall identification rates at the genus and species levels for the saponin method were 89.7% (87/97) and 74.2% (72/97), respectively. With the Zybio Kit, 88.7% (86/97) and 80.4% (78/97) of microorganisms were correctly identified to the genus and species levels, respectively. The saponin method identified 65.3% (32/49) of Gram-positive bacteria at the species level, whereas the Zybio Kit achieved a higher species-level identification rate of 79.6% (39/49) (p = 0.1153). The saponin method with additional on-plate formic acid extraction showed a significantly higher overall identification rate in comparison to the saponin method without that step for both genus (87.6% [85/97] vs. 70.1% [68/97], p = 0.0029) and species level (70.1% [68/97] vs. 46.4% [45/97], p = 0.0008). Identification rates of Gram-negative bacteria showed a higher identification rate, however, not statistically significant with additional Zybio Kit protocol step on both genus (85.4% [41/48] vs. 81.3% [39/48], p = 0.5858) and species level (77.1% [37/48] vs. 75% [36/48], p = 0.8120). Zybio Kit could offer an advantage in species-level identification, particularly for Gram-positive bacteria. The inclusion of on-plate formic acid extraction in the saponin method notably enhanced identification at both genus and species levels for Gram-positive bacteria. The extended protocol provided by the Zybio Kit could potentially offer an advantage in the identification of Gram-negative bacteria at both genus and species levels. Enhancements to the Zybio EXS2600 MALDI-TOF instrument software database are necessary.

Asunto(s)

Bacterias , Cultivo de Sangre , Saponinas , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Saponinas/química , Saponinas/análisis , Humanos , Bacterias/aislamiento & purificación , Bacterias/clasificación , Bacterias/química , Cultivo de Sangre/métodos , Bacterias Gramnegativas/aislamiento & purificación , Juego de Reactivos para Diagnóstico , Bacterias Grampositivas/aislamiento & purificación , Bacterias Grampositivas/clasificación , Técnicas de Tipificación Bacteriana/métodos

RESUMEN

Silver nanoparticles (AgNPs) synthesized from plant extracts have gained attention for their potential applications in biomedicine. Calotropis gigantea has been utilized to synthesize AgNPs, called AgNPs-LCg, and exhibit antibacterial activities against both Gram-positive and Gram-negative bacteria as well as antifungal. However, further enhancement of their antimicrobial properties is needed. The aim of this study was to synthesize AgNPs-LCg and to enhance their antimicrobial and antifungal activities through a hybrid green synthesis reaction using patchouli oil (PO), as well as to characterize the synthesized AgNPs-LCg. Optimization was conducted using the response surface method (RSM) with a central composite design (CCD). AgNPs-LCg were synthesized under optimal conditions and hybridized with different forms of PO-crude, distillation wastewater (hydrolate), and heavy and light fractions-resulting in PO-AgNPs-LCg, PH-AgNPs-LCg, LP-AgNPs-LCg, and HP-AgNPs-LCg, respectively. The samples were then tested for their antibacterial (both Gram-positive and Gram-negative bacteria) and antifungal activities. Our data indicated that all samples, including those with distillation wastewater, had enhanced antimicrobial activity. HP-AgNPs-LCg, however, had the highest efficacy; therefore, only HP-AgNPs-LCg proceeded to the characterization stage for comparison with AgNPs-LCg. UV-Vis spectrophotometry indicated surface plasmon resonance (SPR) peaks at 400 nm for AgNPs-LCg and 360 nm for HP-AgNPs-LCg. The Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the presence of O-H, N-H, and C-H groups in C. gigantea extract and AgNP samples. The smallest AgNPs-LCg were 56 nm, indicating successful RSM optimization. Scanning electron microscopy (SEM) analysis revealed spherical AgNPs-LCg and primarily cubic HP-AgNPs-LCg, with energy-dispersive X-ray spectroscopy (EDX) confirming silver's predominance. This study demonstrated that PO in any form significantly enhances the antimicrobial properties of AgNPs-LCg. The findings pave the way for the exploration of enhanced and environmentally sustainable antimicrobial agents, capitalizing on the natural resources found in Aceh Province, Indonesia.

Asunto(s)

Calotropis , Tecnología Química Verde , Nanopartículas del Metal , Pruebas de Sensibilidad Microbiana , Hojas de la Planta , Plata , Nanopartículas del Metal/química , Plata/química , Plata/farmacología , Tecnología Química Verde/métodos , Hojas de la Planta/química , Calotropis/química , Bacterias Grampositivas/efectos de los fármacos , Bacterias Gramnegativas/efectos de los fármacos , Extractos Vegetales/química , Extractos Vegetales/farmacología , Antiinfecciosos/farmacología , Antiinfecciosos/química , Antifúngicos/farmacología , Antifúngicos/química , Antifúngicos/síntesis química , Antibacterianos/farmacología , Antibacterianos/química , Antibacterianos/síntesis química , Aceites de Plantas/farmacología , Aceites de Plantas/química

RESUMEN

The cell wall is an indispensable element of bacterial cells and a long-known target of many antibiotics. Penicillin, the first discovered beta-lactam antibiotic inhibiting the synthesis of cell walls, was successfully used to cure many bacterial infections. Unfortunately, pathogens eventually developed resistance to it. This started an arms race, and while novel beta-lactams, either natural or (semi)synthetic, were discovered, soon upon their application, bacteria were developing resistance. Currently, we are facing the threat of losing the race since more and more multidrug-resistant (MDR) pathogens are emerging. Therefore, there is an urgent need for developing novel approaches to combat MDR bacteria. The cell wall is a reasonable candidate for a target as it differentiates not only bacterial and human cells but also has a specific composition unique to various groups of bacteria. This ensures the safety and specificity of novel antibacterial agents that target this structure. Due to the shortage of low-molecular-weight candidates for novel antibiotics, attention was focused on peptides and proteins that possess antibacterial activity. Here, we describe proteinaceous agents of various origins that target bacterial cell wall, including bacteriocins and phage and bacterial lysins, as alternatives to classic antibiotic candidates for antimicrobial drugs. Moreover, advancements in protein chemistry and engineering currently allow for the production of stable, specific, and effective drugs. Finally, we introduce the concept of selective targeting of dangerous pathogens, exemplified by staphylococci, by agents specifically disrupting their cell walls.

Asunto(s)

Antibacterianos , Pared Celular , Bacterias Grampositivas , Pared Celular/efectos de los fármacos , Antibacterianos/farmacología , Antibacterianos/química , Bacterias Grampositivas/efectos de los fármacos , Humanos , Bacteriocinas/farmacología , Bacteriocinas/química , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Infecciones por Bacterias Grampositivas/microbiología , Bacteriófagos

RESUMEN

The RNA-based study provides an excellent indication of an organism's gene expression profile. Obtaining high-yield and high-purity RNA from Gram-positive and acid-fast bacteria is difficult without high-end kits and facilities. We optimised effective and simple protocol for RNA isolation that is a combination of enzymatic, physical and chemical treatment to disrupt cells. We successfully isolated high quality intact total RNA with yields ranging from 23.13 ± 0.40 to 61.51 ± 0.27 µg and the 260/280 purity ratio of 1.95 ± 0.01 to 2.05 ± 0.01 from Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, and Mycobacterium smegmatis. These results represents a significantly enhanced yield and purity compared to other combination of techniques which we performed. Compared to previous studies the yield obtained by this method is high for the studied organisms. Furthermore the yielded RNA was successfully used for downstream applications such as quantitative real time PCR. The described method can be easily optimised and used for various bacteria.

Asunto(s)

ARN Bacteriano , ARN Bacteriano/genética , ARN Bacteriano/aislamiento & purificación , Staphylococcus aureus/genética , Staphylococcus aureus/aislamiento & purificación , Bacterias Grampositivas/genética , Bacterias Grampositivas/aislamiento & purificación , Staphylococcus epidermidis/genética , Staphylococcus epidermidis/aislamiento & purificación , Enterococcus faecalis/genética , Enterococcus faecalis/aislamiento & purificación , Mycobacterium smegmatis/genética

RESUMEN

Bacterial growing resistance to antibiotics poses a critical threat to global health. This study investigates, for the first time, the antibiofilm properties of Vicia ervilia agglutinin (VEA) from six different V. ervilia accessions against pathogenic bacteria, and the yeast Candida albicans. In the absence of antimicrobial properties, purified VEA significantly inhibited biofilm formation, both in Gram-positive and Gram-negative bacteria, but not in C. albicans. With an inhibitory concentration ranging from 100 to 500 µg/ml, the VEA antibiofilm activity was more relevant against the Gram-positive bacteria Streptococcus aureus and Staphylococcus epidermidis, whose biofilm was reduced up to 50% by VEA purified from accessions #5 and #36. VEA antibiofilm variability between accessions was observed, likely due to co-purified small molecules rather than differences in VEA protein sequences. In conclusion, VEA seed extracts from the accessions with the highest antibiofilm activity could represent a valid approach for the development of an effective antibiofilm agent.

Asunto(s)

Antibacterianos , Biopelículas , Candida albicans , Bacterias Gramnegativas , Bacterias Grampositivas , Pruebas de Sensibilidad Microbiana , Biopelículas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Bacterias Gramnegativas/efectos de los fármacos , Candida albicans/efectos de los fármacos , Candida albicans/fisiología , Antibacterianos/farmacología , Lectinas de Plantas/farmacología , Extractos Vegetales/farmacología , Extractos Vegetales/química , Semillas/química

RESUMEN

Endophytic bacteria found in marine macroalgae have been studied for their potential antimicrobial activity, consequently, they could serve as a valuable source of bioactive compounds to control pathogenic bacteria, yeasts, and fungi. Algae endophytic bacteria were isolated from Caulerpa sp., Ulva sp., Ahnfeltiopsis sp., and Chondracantus chamissoi from Yacila and Cangrejo Beaches (Piura, Peru). Antimicrobial assays against pathogenic bacteria were evaluated using cross-culture, over-plate, and volatile organic compound tests. Afterward, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of selected crude extracts were determined, also ITS molecular analysis, antifungal activity, and PCR of iturin, fengycin, and surfactin genes were performed for bacteria strains exhibiting better activity. Forty-six algae endophytic bacteria were isolated from algae. Ten strains inhibited gram-positive pathogenic bacteria (Enterococcus faecalis, Staphylococcus epidermidis, S. aureus, and Listeria monocytogenes), and 12 inhibited gram-negative bacteria (Escherichia coli and Salmonella enteric sv typhimurium). Bacteria with better activity belong to Bacillus sp., Kluyvera ascorbata, Pantoea agglomerans, Leclercia adecarboxylata, and Enterobacter sp., which only four showed antifungal activities against Candida albicans, C. tropicalis, Colletotrichium sp., Fusarium sp., Fusarium oxysporum, and Alternaria sp. Furthermore, K. ascorbata YAFE21 and Bacillus sp. YCFE4 exhibited iturin and fengycin genes. The results indicate that the algae endophytic bacteria found in this study, particularly K. ascorbata YAFE21, Bacillus sp. YCFR6, L. adecarboxylata CUFE2, Bacillus sp. YUFE8, Enterobacter sp. YAFL1, and P. agglomerans YAFL6, could be investigated as potential producers of antimicrobial compounds due to their broad activity against various microorganisms.

Asunto(s)

Endófitos , Pruebas de Sensibilidad Microbiana , Algas Marinas , Endófitos/aislamiento & purificación , Endófitos/genética , Endófitos/metabolismo , Endófitos/química , Endófitos/clasificación , Algas Marinas/microbiología , Bacterias/efectos de los fármacos , Bacterias/aislamiento & purificación , Bacterias/clasificación , Antiinfecciosos/farmacología , Antiinfecciosos/aislamiento & purificación , Antibacterianos/farmacología , Antibacterianos/aislamiento & purificación , Antifúngicos/farmacología , Antifúngicos/aislamiento & purificación , Hongos/efectos de los fármacos , Hongos/aislamiento & purificación , Hongos/clasificación , Bacterias Gramnegativas/efectos de los fármacos , Ulva/microbiología , Caulerpa/microbiología , Bacterias Grampositivas/efectos de los fármacos

RESUMEN

Microbial infections pose a significant global health threat, affecting millions of individuals and leading to substantial mortality rates. The increasing resistance of microorganisms to conventional treatments requires the development of novel antimicrobial agents. Pyrroloquinoline quinone (PQQ), a natural medicinal drug involved in various cellular processes, holds promise as a potential antimicrobial agent. In the present study, our aim was, for the first time, to explore the antimicrobial activity of PQQ against 29 pathogenic microbes, including 13 fungal strains, 8 Gram-positive bacteria, and 8 Gram-negative bacteria. Our findings revealed potent antifungal properties of PQQ, particularly against Syncephalastrum racemosum, Talaromyces marneffei, Candida lipolytica, and Trichophyton rubrum. The MIC values varied between fungal strains, and T. marneffei exhibited a lower MIC, indicating a greater susceptibility to PQQ. In addition, PQQ exhibited notable antibacterial activity against Gram-positive and -negative bacteria, with a prominent inhibition observed against Staphylococcus epidermidis, Proteus vulgaris, and MRSA strains. Remarkably, PQQ demonstrated considerable biofilm inhibition against the MRSA, S. epidermidis, and P. vulgaris strains. Transmission electron microscopy (TEM) studies revealed that PQQ caused structural damage and disrupted cell metabolism in bacterial cells, leading to aberrant morphology, compromised cell membrane integrity, and leakage of cytoplasmic contents. These findings were further affirmed by shotgun proteomic analysis, which revealed that PQQ targets several important cellular processes in bacteria, including membrane proteins, ATP metabolic processes, DNA repair processes, metal-binding proteins, and stress response. Finally, detailed molecular modeling investigations indicated that PQQ exhibits a substantial binding affinity score for key microbial targets, including the mannoprotein Mp1P, the transcriptional regulator TcaR, and the endonuclease PvuRTs1I. Taken together, our study underscores the effectiveness of PQQ as a broad-spectrum antimicrobial agent capable of combating pathogenic fungi and bacteria, while also inhibiting biofilm formation and targeting several critical biological processes, making it a promising therapeutic option for biofilm-related infections.

Asunto(s)

Biopelículas , Pruebas de Sensibilidad Microbiana , Cofactor PQQ , Proteómica , Biopelículas/efectos de los fármacos , Cofactor PQQ/farmacología , Cofactor PQQ/química , Antibacterianos/farmacología , Antibacterianos/química , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Antiinfecciosos/farmacología , Antiinfecciosos/química , Simulación por Computador , Hongos/efectos de los fármacos , Simulación del Acoplamiento Molecular , Antifúngicos/farmacología , Antifúngicos/química

RESUMEN

The early detection of bacterial species plays a crucial role in patient prognosis and the development of effective therapeutic regimens. This study introduces an accessible and promising colorimetric sensor array designed to classify gram-positive (G+) and gram-negative (G-) bacterial species. The classification relies on 6 chemical ligands with dimethylamino/amino groups as sensing elements and silver nanotriangles as colorimetric probes. Using these specific sensor arrays, we successfully differentiated G- and G+ bacterial species and discriminated individual bacterial strains, and the sensors exhibited remarkable reproducibility and high sensitivity. Moreover, the sensor array can identify bacterial mixtures and bacteria at varying concentrations, underscoring its versatility. In summary, this sensor array offers an effective tool for bacterial analysis with promising applications in the field of biomedical diagnostics.

Asunto(s)

Colorimetría , Ligandos , Colorimetría/métodos , Plata/química , Bacterias Gramnegativas/aislamiento & purificación , Bacterias Gramnegativas/clasificación , Bacterias Grampositivas/aislamiento & purificación , Nanopartículas del Metal/química , Reproducibilidad de los Resultados

RESUMEN

Due to envelope differences between Gram-positive and Gram-negative bacteria, engineering precision bactericidal contractile nanomachines requires atomic-level understanding of their structures; however, only those killing Gram-negative bacteria are currently known. Here, we report the atomic structures of an engineered diffocin, a contractile syringe-like molecular machine that kills the Gram-positive bacterium Clostridioides difficile. Captured in one pre-contraction and two post-contraction states, each structure fashions six proteins in the bacteria-targeting baseplate, two proteins in the energy-storing trunk, and a collar linking the sheath with the membrane-penetrating tube. Compared to contractile machines targeting Gram-negative bacteria, major differences reside in the baseplate and contraction magnitude, consistent with target envelope differences. The multifunctional hub-hydrolase protein connects the tube and baseplate and is positioned to degrade peptidoglycan during penetration. The full-length tape measure protein forms a coiled-coil helix bundle homotrimer spanning the entire diffocin. Our study offers mechanical insights and principles for designing potent protein-based precision antibiotics.

Asunto(s)

Antibacterianos , Bacteriocinas , Clostridioides difficile , Bacteriocinas/química , Bacteriocinas/metabolismo , Bacteriocinas/farmacología , Clostridioides difficile/efectos de los fármacos , Antibacterianos/farmacología , Antibacterianos/química , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Modelos Moleculares , Bacterias Grampositivas/efectos de los fármacos , Peptidoglicano/metabolismo , Peptidoglicano/química , Cristalografía por Rayos X

RESUMEN

Bacterial infections have been a serious threat to mankind throughout history. Natural antimicrobial peptides (AMPs) and their membrane disruption mechanism have generated immense interest in the design and development of synthetic mimetics that could overcome the intrinsic drawbacks of AMPs, such as their susceptibility to proteolytic degradation and low bioavailability. Herein, by exploiting the self-assembly and pore-forming capabilities of sequence-defined peptoids, we discovered a family of low-molecular weight peptoid antibiotics that exhibit excellent broad-spectrum activity and high selectivity toward a panel of clinically significant Gram-positive and Gram-negative bacterial strains, including vancomycin-resistant Enterococcus faecalis (VREF), methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Tuning the peptoid side chain chemistry and structure enabled us to tune the efficacy of antimicrobial activity. Mechanistic studies using transmission electron microscopy (TEM), bacterial membrane depolarization and lysis, and time-kill kinetics assays along with molecular dynamics simulations reveal that these peptoids kill both Gram-positive and Gram-negative bacteria through a membrane disruption mechanism. These robust and biocompatible peptoid-based antibiotics can provide a valuable tool for combating emerging drug resistance.

Asunto(s)

Antibacterianos , Materiales Biocompatibles , Pruebas de Sensibilidad Microbiana , Peptoides , Peptoides/química , Peptoides/farmacología , Antibacterianos/farmacología , Antibacterianos/química , Antibacterianos/síntesis química , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Simulación de Dinámica Molecular , Péptidos Antimicrobianos/química , Péptidos Antimicrobianos/farmacología , Humanos

RESUMEN

Diabetic foot infection imposes a significant burden and is the major cause of nontraumatic limb amputation. Adequate patient management with effective antibiotic therapy is crucial.This retrospective cohort study aimed to characterize the microbiology and resistance patterns of moderate to severe neuropathic diabetic foot infection in patients hospitalized at a tertiary referral hospital between January 2020 and June 2023. Deep tissue specimens from ulcers were collected for culture.Sixty inpatients were included (62% male, mean age 59.1 ± 11.5 years). Osteomyelitis was present in 90% of the patients. Among 102 microorganisms (average of 1.91 ± 1.25 pathogens per patient), 60.8% were gram-positive bacteria, 31.4% were gram-negative, 3.92% were anaerobic bacteria, and 3.92% were fungi. Staphylococcus aureus (19%) and Enterococcus faecium (17%) were the most common. Pseudomonas aeruginosa (8%) and bacteria of the Enterobacterales family (24%) accounted for all the isolated gram-negative bacteria. Sixteen percent of Staphylococcus aureus and 67% of coagulase-negative Staphylococci were resistant to methicillin. Resistance to ampicillin was found in 11% of Enterococci. All Pseudomonas aeruginosa isolates were sensitive to piperacillin-tazobactam, ceftazidime, or cefepime. Among the Enterobacterales, resistance rates were 35% for piperacillin-tazobactam, 38% for ceftazidime, 21% for cefepime, and 13% for carbapenems.Although the prevalence of methicillin-resistant staphylococci was lower than that in other studies, carbapenem resistance among gram-negative bacteria warrants attention. This study highlights the importance of understanding local epidemiology for effective diabetic foot infection management and resistance mitigation.

Asunto(s)

Antibacterianos , Pie Diabético , Centros de Atención Terciaria , Humanos , Pie Diabético/microbiología , Pie Diabético/tratamiento farmacológico , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Centros de Atención Terciaria/estadística & datos numéricos , Femenino , Anciano , Antibacterianos/uso terapéutico , Antibacterianos/farmacología , Portugal/epidemiología , Pruebas de Sensibilidad Microbiana , Osteomielitis/microbiología , Osteomielitis/tratamiento farmacológico , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Gramnegativas/aislamiento & purificación , Bacterias Gramnegativas/clasificación , Bacterias/aislamiento & purificación , Bacterias/clasificación , Bacterias/efectos de los fármacos , Bacterias/genética , Bacterias Grampositivas/efectos de los fármacos , Bacterias Grampositivas/aislamiento & purificación , Bacterias Grampositivas/clasificación

RESUMEN

Antimicrobial resistance represents a global health emergency, necessitating the introduction of novel antimicrobial agents. In the present study, lysozyme and holin from Shigella flexneri 1.1868 phage SGF2, named LysSGF2 and HolSGF2, respectively, were cloned, expressed, and characterized. LysSGF2 and HolSGF2 showed lytic activities against S. flexneri 1.1868 cells at 4-55 °C and pH 3.1-10.3. LysSGF2 exhibited antimicrobial activity against five gram-negative and two gram-positive bacteria. HolSGF2 showed antimicrobial activity against four gram-negative and one gram-positive species. The antibacterial activities of LysSGF2 and HolSGF2 were determined in liquid beverages, including bottled water and milk. The relative lytic activity of LysSGF2 combined with HolSGF2 against the tested bacteria was approximately 46-77 % in water. Furthermore, the combination markedly decreased the viable counts of tested bacteria by approximately 3-5 log CFU/mL. LysSGF2 and HolSGF2 could efficiently remove biofilms on polystyrene, glass, and stainless-steel. The efficacy of the LysSGF2 and HolSGF2 combination against the tested bacteria on polystyrene was 58-71 %. Combination treatment effectively killed biofilm cells formed on stainless-steel and glass by 1-4 log CFU/mL. ese results indicate that LysSGF2 and HolSGF2 can successfully control both the planktonic and biofilm cells of common pathogenic bacteria, suggesting that the combined or single use of LysSGF2 and HolSGF2 may be of great value in food processing.

Asunto(s)

Biopelículas , Biopelículas/efectos de los fármacos , Bacteriófagos , Antibacterianos/farmacología , Plancton/efectos de los fármacos , Shigella flexneri/efectos de los fármacos , Muramidasa/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Animales

RESUMEN

In response to the escalating threat of microbial resistance, a series of novel pleuromutilin derivatives, conjugated with phenyl-sulfide and boron-containing moieties, were designed and synthesized. Most derivatives, especially 14b and 16b, demonstrated significant efficacy against Gram-positive bacteria, including multidrug-resistant strains, as well as pleuromutilin-resistant strains. Compound 16b showed high stability in the liver microsomes of rats and humans, along with acceptable tolerance in vitro and in vivo. Additionally, compound 16b exhibited promising efficacy in MRSA-infected mouse models. Our data highlight the potential of conjugated pleuromutilin derivatives as valuable agents against drug-resistant bacteria.

Asunto(s)

Antibacterianos , Diterpenos , Pruebas de Sensibilidad Microbiana , Pleuromutilinas , Compuestos Policíclicos , Compuestos Policíclicos/química , Compuestos Policíclicos/farmacología , Compuestos Policíclicos/síntesis química , Diterpenos/farmacología , Diterpenos/química , Diterpenos/síntesis química , Antibacterianos/farmacología , Antibacterianos/química , Antibacterianos/síntesis química , Animales , Humanos , Ratones , Ratas , Relación Estructura-Actividad , Estructura Molecular , Relación Dosis-Respuesta a Droga , Farmacorresistencia Bacteriana/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Boro/química , Boro/farmacología , Bacterias Grampositivas/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Microsomas Hepáticos/química

RESUMEN

Antimicrobial resistance has emerged as a significant threat to global public health. To develop novel, high efficiency antibacterial alternatives to combat multidrug-resistant bacteria, A total of thirty-two novel amphiphilic benzopyran derivatives by mimicking the structure and function of antimicrobial peptides were designed and synthesized. Among them, the most promising compounds 4h and 17e displayed excellent antibacterial activity against Gram-positive bacteria (MICs = 1-4 µg/mL) with weak hemolytic activity and good membrane selectivity. Additionally, compounds 4h and 17e had rapid bactericidal properties, low resistance frequency, good plasma stability, and strong capabilities of inhibiting and eliminating bacterial biofilms. Mechanistic studies revealed that compounds 4h and 17e could effectively disrupt the integrity of bacterial cell membranes, and accompanied by an increase in intracellular reactive oxygen species and the leakage of proteins and DNA, ultimately leading to bacterial death. Notably, compound 4h exhibited comparable in vivo antibacterial potency in a mouse septicemia model infected by Staphylococcus aureus ATCC43300, as compared to vancomycin. These findings indicated that 4h might be a promising antibacterial candidate to combat antimicrobial resistance.

Asunto(s)

Antibacterianos , Benzopiranos , Biopelículas , Diseño de Fármacos , Farmacorresistencia Bacteriana Múltiple , Pruebas de Sensibilidad Microbiana , Antibacterianos/farmacología , Antibacterianos/síntesis química , Antibacterianos/química , Benzopiranos/farmacología , Benzopiranos/síntesis química , Benzopiranos/química , Animales , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Ratones , Relación Estructura-Actividad , Biopelículas/efectos de los fármacos , Estructura Molecular , Relación Dosis-Respuesta a Droga , Staphylococcus aureus/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Humanos , Tensoactivos/síntesis química , Tensoactivos/farmacología , Tensoactivos/química

RESUMEN

BACKGROUND: Gram-positive bacteria residing in the nasopharynx can lead to severe illnesses in children, such as otitis media, pneumonia, and meningitis. Despite the potential threat, there is a lack of comprehensive data regarding the carriage rates of these bacteria among children in outpatient departments in the study area. OBJECTIVE: This study aimed to assess the nasopharyngeal carriage, antimicrobial resistance patterns, and associated factors of Gram-positive bacteria among children attending the outpatient department at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia. METHODS: A hospital-based cross-sectional study was conducted from May 1, 2023, to August 30, 2023. A total of 424 nasopharyngeal swab samples were collected using sterile nasopharyngeal swabs, inoculated on Blood Agar and Mannitol Salt Agar plates, and identified through colony morphology, Gram stain, and biochemical tests. Antimicrobial susceptibility of the identified bacterial isolates was determined employing both the Kirby-Bauer and modified Kirby-Bauer methods. D-tests were conducted using clindamycin and erythromycin discs to detect inducible clindamycin resistance, while cefoxitin disc tests were utilized to ascertain methicillin resistance. Data entry was executed using Epi-Data version 4.6, and subsequent analysis was performed utilizing SPSS version 25. Bivariable and multivariable logistic regression analyses were employed to identify associated factors. An adjusted odds ratio at a 95% confidence interval with a P-value of < 0.05 was considered statistically significant. RESULTS: The overall nasopharyngeal carriage rate of Gram-positive bacteria was 296/424 (69.8%, 95% CI: 65.3-74.0). Staphylococcus aureus was the most prevalent 122/424 (28.8%), followed by Streptococcus pneumoniae 92/424 (21.7%). Methicillin resistance was observed in 19/122 (15.6%) of S. aureus and 3/60 (5%) of coagulase-negative staphylococcus (CoNS) species. Inducible clindamycin resistance was 10/122 (8.2%) in S. aureus and 4/53 (7.5%) in coagulase-negative staphylococcus species. Multidrug resistance was found in 146/296 (49.3%, 95% CI: 43.6-55.0) of the isolates. Associated factors with a bacterial carriage were large family size (AOR = 3.061, 95% CI: 1.595-5.874, P = 0.001), having siblings under five years old (AOR = 1.991, 95% CI: 1.196-3.313, P = 0.008), indoor cooking (AOR = 2.195, 95% CI: 1.275-3.778, P = 0.005), an illiterate mother (AOR = 3.639, 95% CI: 1.691-7.829, P = 0.001), and hospital visits (AOR = 2.690, 95% CI: 1.405-5.151, P = 0.003). CONCLUSION: The study found a high nasopharyngeal carriage of Gram-positive bacteria in outpatient children, including notable levels of methicillin-resistant S. aureus and multi-drug-resistant isolates. Clindamycin, rifampin, and erythromycin were the most effective antimicrobials for the tested isolates. Factors contributing to bacterial carriage include visits to healthcare facilities, larger family sizes, having younger siblings, maternal illiteracy, and indoor cooking. This emphasizes the need for methicillin-resistant S. aureus surveillance in pediatric outpatient settings and community health education, especially for children's guardians. Additionally, improving household ventilation by separating kitchens from sleeping areas and regular screening of younger siblings in healthcare environments were recommended to reduce bacterial transmission within family members. The study also called for studies with advanced procedures like minimum inhibitory concentration testing and molecular characterization to better comprehend the resistance patterns and genes in circulating bacteria.

Asunto(s)

Antibacterianos , Pruebas de Sensibilidad Microbiana , Nasofaringe , Humanos , Etiopía/epidemiología , Femenino , Masculino , Nasofaringe/microbiología , Preescolar , Niño , Estudios Transversales , Lactante , Antibacterianos/farmacología , Bacterias Grampositivas/efectos de los fármacos , Bacterias Grampositivas/aislamiento & purificación , Pacientes Ambulatorios/estadística & datos numéricos , Portador Sano/microbiología , Portador Sano/epidemiología , Infecciones por Bacterias Grampositivas/microbiología , Infecciones por Bacterias Grampositivas/epidemiología , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Farmacorresistencia Bacteriana , Adolescente , Streptococcus pneumoniae/efectos de los fármacos , Streptococcus pneumoniae/aislamiento & purificación

RESUMEN

INTRODUCTION: Bloodstream infections are a significant threat to soldiers wounded in combat and contribute to preventable deaths. Novel and combination therapies that can be delivered on the battlefield or in lower roles of care are urgently needed to address the threat of bloodstream infection among military personnel. In this manuscript, we tested the antibacterial capability of silver ions (Ag+), with long-appreciated antibacterial properties, against ESKAPEE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species, and Escherichia coli) pathogens. MATERIALS AND METHODS: We used the GENESYS (RAIN LLC) device to deliver Ag+ to Gram-positive and Gram-negative ESKAPEE organisms grown in broth, human blood, and serum. Following the Ag+ treatment, we quantified the antibacterial effects by quantifying colony-forming units. RESULTS: We found that Ag+ was bactericidal against 5 Gram-negative organisms, K pneumoniae, A baumannii, P aeruginosa, E cloacae, and E coli, and bacteriostatic against 2 Gram-positive organisms, E faecium and S aureus. The whole blood and serum inhibited the bactericidal activity of Ag+ against a common agent of bloodstream infection, P aeruginosa. Finally, when Ag+ was added in conjunction with antibiotic in the presence of whole blood, there was no significant effect of Ag+ over antibiotic alone. CONCLUSIONS: Our results confirmed that Ag+ has broad-spectrum antibacterial properties. However, the therapeutic value of Ag+ may not extend to the treatment of bloodstream infections because of the inhibition of Ag+ activity in blood and serum.

Asunto(s)

Antibacterianos , Plata , Humanos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Plata/farmacología , Plata/uso terapéutico , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/métodos , Escherichia coli/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Pseudomonas aeruginosa/efectos de los fármacos , Klebsiella pneumoniae/efectos de los fármacos

RESUMEN

Strain Lactiplantibacillus plantarum D1 with bacteriocin producing ability was found in the intestine of Gambusia affinis. The bacteriocin was found to have high inhibitory activity against multiple Streptococcus species and several other Gram-positive and Gram-negative bacteria. Bacteriocin was purified from culture supernatant by ion-exchange chromatography, Sep-Pak C18 cartridge, and reverse-phase high-performance liquid chromatography (RP-HPLC). Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectral analysis determined that purified bacteriocin has a molecular mass of 2,731 Da. A partial N-terminal sequence KRKKHKXQIYNNGM was obtained from the Edman analysis. The N-terminal sequence was employed to search against a translation of the draft genome of strain D1. The translated full amino acid sequence of the mature peptide is as follows: NH2- KRKKHKCQIYNNGMPTGQYRWC, which has a molecular weight of 2738 Da. A BLAST search revealed that this bacteriocin was most similar to bactofencin A but differed from it with three amino acid residues. No identical peptide or protein has been previously reported, and this peptide, termed bactofencin YH, was therefore considered to be a new bacteriocin produced by Lactiplantibacillus plantarum D1.

Asunto(s)

Secuencia de Aminoácidos , Antibacterianos , Bacteriocinas , Peso Molecular , Streptococcus , Bacteriocinas/farmacología , Bacteriocinas/química , Bacteriocinas/aislamiento & purificación , Bacteriocinas/metabolismo , Streptococcus/efectos de los fármacos , Streptococcus/genética , Antibacterianos/farmacología , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Pruebas de Sensibilidad Microbiana , Animales , Cromatografía Líquida de Alta Presión , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos

RESUMEN

Strategies to increase the efficacy and/or expand the spectrum of activity of existing antibiotics provide a potentially fast path to clinically address the growing crisis of antibiotic-resistant infections. Here, we report the synthesis, antibacterial efficacy, and mechanistic activity of an unprecedented class of biguanide-antibiotic conjugates. Our lead biguanide-vancomycin conjugate, V-C6-Bg-PhCl (5e), induces highly effective cell killing with up to a 2 orders-of-magnitude improvement over its parent compound, vancomycin (V), against vancomycin-resistant enterococcus. V-C6-Bg-PhCl (5e) also exhibits improved activity against mycobacteria and each of the ESKAPE pathogens, including the Gram-negative organisms. Furthermore, we uncover broad-spectrum killing activity against biofilm-associated Gram-positive and Gram-negative bacteria as well as mycobacteria not observed for clinically used antibiotics such as oritavancin. Mode-of-action studies reveal that vancomycin-like cell wall synthesis inhibition with improved efficacy attributed to enhanced engagement at vancomycin binding sites through biguanide association with relevant cell-surface anions for Gram-positive and Gram-negative bacteria. Due to its potency, remarkably broad activity, and lack of acute mammalian cell toxicity, V-C6-Bg-PhCl (5e) is a promising candidate for treating antibiotic-resistant infections and notoriously difficult-to-treat slowly growing and antibiotic-tolerant bacteria associated with chronic and often incurable infections. More generally, this study offers a new strategy (biguanidinylation) to enhance antibiotic activity and facilitate clinical entry.

Asunto(s)

Antibacterianos , Biguanidas , Biopelículas , Bacterias Gramnegativas , Bacterias Grampositivas , Pruebas de Sensibilidad Microbiana , Vancomicina , Antibacterianos/farmacología , Antibacterianos/química , Antibacterianos/síntesis química , Biopelículas/efectos de los fármacos , Vancomicina/farmacología , Vancomicina/química , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Biguanidas/farmacología , Biguanidas/química , Biguanidas/síntesis química , Mycobacterium/efectos de los fármacos , Estructura Molecular

RESUMEN

CONTEXT: The increase in bacterial resistance to currently available medications, which increases mortality rates, treatment costs is a global problem, and highlights the need for novel classes of antibacterial agents or new molecules that interact synergistically with antimicrobials. OBJECTIVE: The current work explores the potential synergistic effects of certain natural phenylpropanoids and flavonoids on ciprofloxacin (CIP), ampicillin (AMP), gentamicin (GEN), and tetracycline (TET). MATERIALS AND METHODS: The adjuvant role of cinnamic acid, p-coumaric acid, caffeic acid, ferulic acid, ferulic acid methyl ester, sinapic acid, apigenin, and luteolin was evaluated by determining the MIC (minimal inhibitory concentration) values of antibiotics in the presence of subinhibitory concentrations (200, 100, and/or 50 µM) of the compounds in Gram-positive and Gram-negative bacterial strains using a 2-fold broth microdilution method. The 96-well plates were incubated at 37 °C for 18 h, and dimethyl sulfoxide was used as a solvent control. RESULTS: The combination of luteolin with CIP, reduced the MIC values of the antibiotic from 0.625 to 0.3125 µM and to 0.078 µM in 100 and 200 µM concentration, respectively, in sensitive Staphylococcus aureus. Sinapic acid decreased the MIC value of CIP from 0.625 to 0.3125 µM in S. aureus, from 1.56 to 0.78 µM in Klebsiella pneumoniae, and the MIC of GEN from 0.39 to 0.095 µM in Pseudomonas aeruginosa strains. DISCUSSION AND CONCLUSIONS: These findings are useful in delaying the development of resistance, as the required antibacterial effect can be achieved with the use of lower concentrations of antibiotics.

Asunto(s)

Antibacterianos , Sinergismo Farmacológico , Flavonoides , Bacterias Gramnegativas , Bacterias Grampositivas , Pruebas de Sensibilidad Microbiana , Antibacterianos/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Flavonoides/farmacología , Bacterias Grampositivas/efectos de los fármacos , Relación Dosis-Respuesta a Droga

RESUMEN

Gram-positive bacterial infections present a major clinical challenge, with methicillin- and vancomycin-resistant strains continuing to be a cause for concern. In recent years, semisynthetic vancomycin derivatives have been developed to overcome this problem as exemplified by the clinically used telavancin, which exhibits increased antibacterial potency but has also raised toxicity concerns. Thus, glycopeptide antibiotics with enhanced antibacterial activities and improved safety profiles are still necessary. We describe the development of a class of highly potent semisynthetic glycopeptide antibiotics, the guanidino lipoglycopeptides, which contain a positively charged guanidino moiety bearing a variable lipid group. These glycopeptides exhibited enhanced in vitro activity against a panel of Gram-positive bacteria including clinically relevant methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant strains, showed minimal toxicity toward eukaryotic cells, and had a low propensity for resistance selection. Mechanistically, guanidino lipoglycopeptides engaged with bacterial cell wall precursor lipid II with a higher binding affinity than vancomycin. Binding to both wild-type d-Ala-d-Ala lipid II and the vancomycin-resistant d-Ala-d-Lac variant was confirmed, providing insight into the enhanced activity of guanidino lipoglycopeptides against vancomycin-resistant isolates. The in vivo efficacy of guanidino lipoglycopeptide EVG7 was evaluated in a S. aureus murine thigh infection model and a 7-day sepsis survival study, both of which demonstrated superiority to vancomycin. Moreover, the minimal to mild kidney effects at supratherapeutic doses of EVG7 indicate an improved therapeutic safety profile compared with vancomycin. These findings position guanidino lipoglycopeptides as candidates for further development as antibacterial agents for the treatment of clinically relevant multidrug-resistant Gram-positive infections.

Asunto(s)

Antibacterianos , Lipoglucopéptidos , Pruebas de Sensibilidad Microbiana , Animales , Antibacterianos/farmacología , Antibacterianos/química , Antibacterianos/uso terapéutico , Lipoglucopéptidos/farmacología , Lipoglucopéptidos/uso terapéutico , Ratones , Humanos , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Glicopéptidos/farmacología , Glicopéptidos/química , Glicopéptidos/uso terapéutico , Bacterias Grampositivas/efectos de los fármacos , Femenino