Atividade antibacteriana e ensaio time kill com extratos etanólicos vegetais do cerrado tocantinense contra bactérias resistentes à múltiplos fármacos isoladas de lesões de pés diabéticos

Development of multidrug resistant bacterial strains has become a global concern. Medicinal plants have been explored as a source of molecules with therapeutic potential for the treatment of various diseases and to the development of better drug against bacterial infections. Thus, the aim of this study was to evaluate the antibacterial activity of the bark and leaves extracts of Anacardium humile (St.) Hil, bark extract of Davilla nitida (Vahl.) kubitski, of leaf extract of Kalanchoe pinnata (Lam.) Pers. and against multidrug resistant bacteria isolated from diabetic foot infections, and also of reference strains from the American Type Culture Collection (ATCC). Antibacterial activity of the bark extract was evaluated by agar Disk-Diffusion (DD), Broth Dilution (BD), “Checkerboard” and “Time-Kill” methods. The bark extract of Davilla nitida (Vahl.) kubistki showed a significant antibacterial activity against all groups of bacteria tested. Broth dilution was more sensitive for determining the antibacterial activity of the bark extract than the Disk-Difusion method. The bark extract inhibited the growth of bacteria with high-levels of antibiotic-resistance, such as Pseudomonas spp. (100,00%), Enterobacer spp. (88,89%), Staphylococcus aureus (54,55%), Streptococcus pneumoniae (75,00%), Staphylococcus saprophyticus (92,86%). The combination of extract with antibiotics resulted in an additive effect against most of the strains tested. “Time-Kill” kinetics profiles of bark extract showed bactericidal and time-dependent properties. Our results suggest the presence of bioactive compounds in this plant that could be useful for the development of new antibacterial agents. The leaf extract of Kalanchoe pinnata (Lam.) Pers. showed antibacterial activity against Citrobacter spp. (100,00%), Citrobacter youngae (ATCC-29935) (100,00%), Enterobacer spp. (33.33%), Pseumodonas spp. (66.67%), Pseudomonas aeruginosa (ATCC-27853) (100.00%). Extract of leaf associated with amoxicillin/clavulanic acid or cefoxitin antibiotics did not show any potentiation of antibacterial activity against both Gram-positive and Gram-negative bacteria, suggesting that extract and antibiotics have independent mechanisms related to inhibition of bacterial growth. Our results showed that the ethanolic leaf extract of Kalanchoe pinnata (Lam.) Pers. had a good antimicrobial activity against some multidrug resistant bacteria. However, further and more specific studies, are recommended to determine the efficacy of this extract in the treatment of bacterial infections. Barks and leaves extracts of Anacardium humile (St.) Hil, both in the Disk-Difusion and Broth Dilution methods, inhibited the growth of Gram-positive and Gram-negative bacteria, as well as the growth of bacteria commonly found in diabetic foot lesions. By the “Checkerboard” method, the combination of bark extract (35,00%) and leaves (40,00%) on Gram-negative bacteria had similar synergistic effects, while for Gram-positive bacteria, leaf extracts (45,00%) presented a synergistic effect more effective than the bark extracts (17,50%). The “Time-Kill” kinetic profile showed bactericidal activity with dose and time-dependent properties, suggesting that bark and leaf extracts may potentiate the effects of antibiotics, suggesting that Anacardium humile (St.) Hil extracts can be used with an alternative source of research for antibacterial agents acting on multidrug resistant Gram- positive and Gram- negative bacteria. However, the isolation of bioactive compounds and additional studies should be performed to understand the mechanisms of bactericidal action, to define real efficacy and toxic effects.O desenvolvimento de cepas bacterianas multirresistentes tornou-se uma preocupação global. As plantas medicinais têm sido exploradas como uma fonte potencial terapêutica para o tratamento de várias doenças e para o desenvolvimento de medicamentos mais eficazes contra infecções bacterianas. Assim, o objetivo deste estudo foi avaliar a atividade antibacteriana do extrato de cascas e folhas de Anacardium humile (St.) Hil, extrato de cascas de Davilla nítida (Vahl.) Kubitski, e extrato de folhas de Kalanchoe pinnata (Lam.) Pers. contra bactérias resistentes a múltiplos fármacos isoladas de infecções do pé diabético, e também contra cepas de referência da American Type Culture Collection (ATCC). A atividade antibacteriana foi avaliada pelos métodos de Ágar Disco-Difusão (DD), Microdiluição em Caldo (MC), Ensaio “Checkerboard” e Ensaio “Time-Kill”. O extrato das cascas de Davilla nitida (Vahl.) Kubitski mostrou atividade antibacteriana expressiva contra todos os grupos de bactérias testadas. O método de microdiluição em caldo foi mais sensível que o método disco-difusão para determinar a atividade antibacteriana presente no extrato das cascas. O extrato de cascas inibiu o crescimento de bactérias com altos níveis de resistência aos antibióticos, como Pseudomonas spp. (100,00%), Enterobacter spp. (88,89%), Staphylococcus aureus (54,55%), Streptococcus pneumoniae (75,00%), Staphylococcus saprophyticus (92,86%). A combinação do extrato das cascas com antibióticos resultou em efeito aditivo contra a maioria das cepas testadas. O perfil cinético de tempo de morte do extrato de cascas mostrou propriedades bactericidas tempo-dependentes. Nossos resultados sugerem a presença de compostos bioativos nesta planta que podem ser utilizados para o desenvolvimento de novos agentes antibacterianos. O extrato de folhas de Kalanchoe pinnata (Lam.) Pers. mostrou atividade antibacteriana contra Citrobacter spp. (100,00%), Citrobacter youngae (ATCC-29935) (100,00%), Enterobacter spp. (33,33%), Pseumodonas spp. (66,67%), Pseudomonas aeruginosa (ATCC-27853) (100,00%). O extrato de folhas quando associado com antibiótico amoxicilina/ácido clavulânico ou cefoxitina não evidenciou qualquer potencialização da atividade antibacteriana contra as bactérias Gram-positivas e Gram-negativas, sugerindo que extrato e antibióticos possuem mecanismos independentes relacionados à inibição do crescimento bacteriano. Nossos resultados mostraram que o extrato etanólico das folhas de Kalanchoe pinnata (Lam.) Pers. teve uma boa atividade antimicrobiana contra algumas bactérias resistentes a múltiplos fármacos. Entretanto, estudos adicionais e mais específicos são recomendados para determinar a eficácia deste extrato no tratamento de infecções bacterianas. O extrato das cascas e folhas de Anacardium humile (St.) Hil, tanto no método Disco-difusão quanto em microdiluição em caldo, inibiu significantemente o crescimento das bactérias Gram-positivas e Gram-negativas, como também o crescimento das bactérias comumente encontradas em lesões de pés diabéticos. Pelo método “Checkerboard”, a combinação do extrato das cascas (35,00%) e folhas (40,00%) sobre as bactérias Gram-negativas apresentaram efeitos sinérgicos semelhantes, enquanto que para as bactérias Gram-positivas, os extratos das folhas (45,00%) apresentaram um efeito sinérgico mais efetivo do que os extratos das cascas (17,50%). O perfil cinético “Time-Kill” apresentou atividade bactericida com propriedades dose e tempo dependente, sugerindo que os extratos das cascas e folhas podem potencializar os efeitos dos antibióticos, o que sugere que os extratos de Anacardium humile (St.) Hil podem ser usados com uma fonte alternativa de pesquisa para agentes antibacterianos com ação em bactérias Gram-positivas e Gram-negativas resistentes a multidrogas. No entanto, o isolamento dos compostos bioativos e estudos adicionais devem ser realizados para entender os mecanismos de ação bactericida, para definir a real eficácia e os efeitos tóxicos

Actividad biológica de la Guazuma ulmifolia Lamark.- revisión sistemática

ABSTRACT The Guazuma ulmifolia Lamark (Malvaceae) is a non-endemic plant, popularly known as mutamba. Its leaves and roots are used in home remedies against dysentery and diarrhea, in the treatment of prostate, as a uterine stimulant and other diseases. Due to the characteristics presented and the growing interest in this species, a systematic review was carried out on the possible pharmacological and toxicological effects of Guazuma ulmifolia Lamark. As active compounds, the articles cited the presence of flavonoids, saponins, alkaloids, tannins, phenolic compounds and steroids in different parts of the plant and extracted with different solvents. Regarding the experimental studies, no articles were found with clinical test, and only 4 in vivo studies. About the pharmacological effects we can mention activity against leishmaniasis, hypoglycemic, anti-inflammatory, anticholinesterase, anti-obesity, antiseptic, cicatrizant and anthelmintic. The registered toxicological tests were directed against lineages of cancer cells, proving effective, however, there is a need for studies to attest the safety of G. ulmifolia use by the population. Therefore, it is imperative to carry out further studies to ensure the use of this plant, to know doses and form of indication, as well as clinical studies in order to guarantee a correct therapy. Keywords: Guazuma ulmifolia, toxicity, medicinal plants.    RESUMO A Guazuma ulmifolia Lamark (Malvaceae) é uma planta não endêmica, popularmente conhecida por mutamba. Suas folhas e raízes são empregadas em remédios caseiros contra disenteria e diarreias, no tratamento de próstata, como estimulante uterino e outras enfermidades. Em virtude das características apresentadas e o crescente interesse por esta espécie, tanto para fins medicinais como alimentício, realizou-se uma revisão sistemática sobre os possíveis efeitos farmacológicos e toxicológicos da Guazuma ulmifolia Lamark. Como compostos ativos, os artigos citaram a presença de flavonoides, saponinas, alcaloides, taninos, compostos fenólicos e esteróides em diferentes partes da planta e extraídos com diferentes solventes. Quanto aos estudos experimentais, não foram encontrados artigos com teste clínico e, apenas 4 estudos com testes in vivo. Dos efeitos farmacológicos encontrados, pode-se citar atividade contra leishmaniose, hipoglicemiante, antiinflamatório, anticolinesterásico, antiobesidade, antisséptico, cicatrizante e anti-helmíntico. Os testes toxicológicos registrados foram direcionados contra linhagens de células cancerígenas mostrando-se efetivo, porém, há necessidade de estudos para atestar a segurança de uso de G. ulmifolia pela população. Logo, apesar de utilizada, é imperativa a realização de mais estudos para assegurar o uso desta planta pela população e conhecer doses e forma de indicação, além de estudos clínicos que garantam uma correta terapêutica. Palavras-chave: Guazuma ulmifolia, toxicidade, plantas medicinais.RESUMEN La Guazuma ulmifolia Lamark (Malvaceae) es una planta no endémica, popularmente conocida por mutamba. Sus hojas y raíces son empleadas en remedios caseros contra disentería y diarreas, en el tratamiento de próstata, como estimulante uterino y otras enfermedades. En virtud de las características presentadas y el creciente interés por esta especie, tanto para fines medicinales como alimenticios, se realizó una revisión sistemática sobre los posibles efectos farmacológicos y toxicológicos de la Guazuma ulmifolia Lamark. Como compuestos activos, los artículos citaron la presencia de flavonoides, saponinas, alcaloides, taninos, compuestos fenólicos y esteroides en diferentes partes de la planta y extraídos con diferentes solventes. En cuanto a los estudios experimentales, no se encontraron artículos con prueba clínica y, sólo 4 estudios con pruebas in vivo. De los efectos farmacológicos encontrados, se puede citar actividad contra leishmaniasis, hipoglicemiante, antiinflamatorio, anticolinesterásico, antiobesidad, antiséptico, cicatrizante y antihelmíntico. Las pruebas toxicológicas registradas se dirigieron contra los linajes de las células cancerígenas que se mostraron efectivos, pero hay necesidad de estudios para certificar la seguridad de uso de G. ulmifolia por la población. Por lo tanto, a pesar de ser utilizada, es imperativa la realización de más estudios para asegurar el uso de esta planta por la población y conocer dosis y forma de indicación, además de estudios clínicos que garanticen una correcta terapéutica. Descriptores: Guazuma ulmifolia, toxicidad, plantas medicinales

Aerobic bacterial profile and antibiotic resistance in patients with diabetic foot infections

ABSTRACTINTRODUCTION: This study aimed to determine the frequencies of bacterial isolates cultured from diabetic foot infections and assess their resistance and susceptibility to commonly used antibiotics.METHODS: This prospective study included 41 patients with diabetic foot lesions. Bacteria were isolated from foot lesions, and their antibiotic susceptibility pattern was determined using the Kirby-Bauer disk diffusion method and/or broth method [minimum inhibitory concentration (MIC)].RESULTS: The most common location of ulceration was the toe (54%), followed by the plantar surface (27%) and dorsal portion (19%). A total of 89 bacterial isolates were obtained from 30 patients. The infections were predominantly due to Gram-positive bacteria and polymicrobial bacteremia. The most commonly isolated Gram-positive bacteria were Staphylococcus aureus, followed by Staphylococcus saprophyticus, Staphylococcus epidermidis, Streptococcus agalactiae, and Streptococcus pneumoniae. The most commonly isolated Gram-negative bacteria were Proteus spp. and Enterobacterspp., followed by Escherichia coli, Pseudomonasspp., and Citrobacterspp. Nine cases of methicillin-resistant Staphylococcus aureus (MRSA) had cefoxitin resistance, and among these MRSA isolates, 3 were resistant to vancomycin with the MIC technique. The antibiotic imipenem was the most effective against both Gram-positive and Gram-negative bacteria, and gentamicin was effective against Gram-negative bacteria.CONCLUSIONS: The present study confirmed the high prevalence of multidrug-resistant pathogens in diabetic foot ulcers. It is necessary to evaluate the different microorganisms infecting the wound and to know the antibiotic susceptibility patterns of the isolates from the infected wound. This knowledge is crucial for planning treatment with the appropriate antibiotics, reducing resistance patterns, and minimizing healthcare costs

Evaluation of antibacterial activity of the bark and leaf extracts of <i>Brosimum gaudichaudii</i> Trécul against multidrug resistant strains

<p><i>Brosimum gaudichaudii</i> Trécul., a plant that belongs to <i>Moraceae</i> family, is found throughout the Brazilian Cerrado. The antimicrobial activities of ethanolic bark and leaf extracts of <i>B. gaudichaudii</i> were tested against multiresistant bacteria isolated from diabetic foot infections (DFIs). Antimicrobial activity of the extracts was evaluated by agar disc diffusion (DD) and broth dilution (BD) methods. By BD method, bark (53.85, 45.83%) and leaf (42.31, 50.00%) extracts contained antimicrobial activity against both gram-negative and gram-positive bacteria. Increased antimicrobial activity was observed when bark and leaf extracts were tested against <i>Staphylococcus aureus</i> (63.64%) and <i>Pseudomonas aeruginosa</i> (66.67%). Statistical analyses of bark and leaf extract demonstrated antimicrobial activity against both gram-positive (<i>p</i> = <i>0.000</i>) and gram-negative bacteria (<i>p</i> = <i>0.012</i>). Extract of bark (<i>p</i> = 0.075) or leaf (<i>p</i> = 0.005) associated with ACA antibiotic showed antimicrobial activity against gram-positive bacteria. Our study suggests that the bark and leaf extracts contain bioactive compounds with antimicrobial activity against multidrug resistant strains.</p