Modulation of the norfloxacin resistance in Staphylococcus aureus by Cordia verbenaceae DC.

BACKGROUND & OBJECTIVES: Several chemical compounds isolated from natural sources have antibacterial activity and some enhance the antibacterial activity of antibiotics reversing the natural resistance of bacteria to certain antibiotics. In this study, the hexane and methanol extract of Cordia verbenaceae were assessed for antibacterial activity alone and combinated with norfloxacin against the Staphylococcus aureus strain SA1199B. METHODS: The minimum inhibitory concentration (MIC) of extracts was assayed using microdilution assay and the modulatory activity was evaluated using plate diffusion assay. RESULTS: The MIC observed varied between 256 to >1024 µg/ml. However, the antibiotic activity of norfloxacin was enhanced in the presence of subinhibitory concentrations of hexane extract of C. verbenaceae (HECV). INTERPRETATIONS & CONCLUSIONS: Our results indicate that Cordia verbenaceae DC. can be a source of plant derived products with antibiotic modifying activity.

Modulation of drug resistance in Staphylococcus aureus by extract of mango (Mangifera indica L., Anacardiaceae) peel

In an ongoing project to evaluate natural compounds isolated from by-products or wastes from vegetables and fruits (edible plants) as modulators of antibiotic resistance, ethanol extract from mango peel was investigated using Staphylococcus aureus strains possessing efflux mechanisms of resistance to norfloxacin, erythromycin and tetracycline. The minimum inhibitory concentrations (MIC) of the antibiotics were determined by the micro dilution assay in the absence and in the presence of sub-inhibitory mango peel extract concentration. Although the extract did not display relevant antibacterial activity (MIC>2048 µg/mL), it modulated the activity of antibiotics, i.e. in combination with antibiotics (at 512 µg/mL), a four-fold reduction in the MIC values for tetracycline and erythromycin was observed. The results presented here indicates that mango peel could serve as a source of potential adjuvant of antibiotics which add value to this mango by-product.

Modulation of the norfloxacin resistance in Staphylococcus aureus by Croton campestris A. and Ocimum gratissimum L.

INTRODUCTION: Some species of Staphylococcus are often recognized as etiological agents of many animal and human opportunistic infections. This study is the first test of change in resistance of antibiotic activity by Croton campestris A. and Ocimum gratissimum L. against multiresistant strains of Staphylococcus aureus. OBJECTIVE: In this study, the hexane and methanol extract of Croton campestris A. and Ocimum gratissimum L. was tested for antibacterial activity alone and in combination with norfloxacin against the strain SA1199B. MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) and the modulatory effect of extracts was assayed using microtitre assay. RESULTS: By the fact of the MIC observed was not clinically relevant (MIC= 512 to ≥1.024 µg/ml), the antibiotic activity of norfloxacin was enhanced when this antibiotic was combined with sub-inhibitory concentrations of extracts, mainly the hexane extracts. CONCLUSIONS: These results indicate that the assayed extracts present compounds that can be used as a putative efflux pump inhibitor, indicating that Croton campestris A. and Ocimum gratissimum L. can be a source of plant derived products with antibiotic modifier activity.

In vitro additive effect of Hyptis martiusii in the resistance to aminoglycosides of methicillin-resistant Staphylococcus aureus.

CONTEXT: Bacterial infectious agents represent a risk to populations, where they are responsible for the high morbidity and mortality. In combating these pathogens, our main line of defense is the use of antibiotics. However, the indiscriminate use of these drugs select resistant strains to these same drugs. OBJECTIVE: In this study the ethanol extract of Hyptis martiusii Benth. (EEHM) (Lamiaceae) was tested for its antimicrobial activity against aminoglycoside multi-resistant Staphylococcus aureus (MRSA). MATERIALS AND METHODS: In this study, the ethanol extract of H. martiusii was prepared and tested with chlorpromazine for its antimicrobial activity using the microdilution method. Chlorpromazine and the ethanol extract were used alone and also in combination with aminoglycosides against a MRSA strain resistant to these antibiotics to determine the participation of efflux systems in resistance mechanisms. The FIC index was calculated and evaluated by the checkerboard method. RESULTS: A potentiating effect between this extract and aminoglycosides was demonstrated. Similarly, a potentiating effect of chlorpromazine with kanamycin was detected, indicating the involvement of an efflux system in the resistance to this aminoglycoside. The checkerboard method with combinations of aminoglycosides and EEHM demonstrated additive effect with kanamycin and gentamicin. It is therefore suggested that extracts from H. martiusii could be used as a source of plant-derived natural products with resistance- modifying activity. CONCLUSION: This is the first report about the modifying antibiotic activity of Hyptis martiusii, constituting a new approach against bacterial resistance to antibiotics as aminoglycosides.

Potentiation of antibiotic activity by Eugenia uniflora and Eugenia jambolanum.

This is the first report about the modifying antibiotic activity of Eugenia uniflora L. and Eugenia jambolanum L. In this study the ethanol extract of E. uniflora and E. jambolanum was tested for their antimicrobial activity against strains of Escherichia coli. The growth of the two strains of E. coli bacteria tested was not inhibited in a clinically relevant form by the extract. The minimal inhibitory concentration was >or=1,024 microg/mL for both strains of E. coli assayed. Synergism between this extract and gentamicin was demonstrated. In the same extract synergism was observed between chlorpromazine and kanamycin and between amikacin and tobramycin, indicating the involvement of an efflux system in the resistance to these aminoglycosides. It is therefore suggested that extracts from E. uniflora L. and E. jambolanum L. could be used as a source of plant-derived natural products with modifying antibiotic activity to gentamicin.

Effect of Momordica charantia L. in the resistance to aminoglycosides in methicilin-resistant Staphylococcus aureus.

In this study the ethanol extract (EEMC) of Momordica charantia L. (Cucurbitaceae) was tested for its modifying antibiotic activity against a MRSA strain. The growth of an MRSA (SA358) in the absence and presence of aminoglycosides was evaluated. A potentiating effect between this extract and all aminoglycosides was demonstrated. Similarly, the same effect was shown by chlorpromazine on kanamycin, gentamicin and neomycin, indicating the involvement of an efflux system in the resistance to these aminoglycosides. Extracts from M. charantia could be used as a source of plant-derived natural products with resistance-modifying activity. This is the first report about the modifying antibiotic activity of M. charantia, constituting a new weapon against multi-resistant bacteria such as MRSA.

Increasing of the aminoglicosyde antibiotic activity against a multidrug-resistant E. coli by Turnera ulmifolia L. and chlorpromazine.

In this study, an ethanol extract of Turnera ulmifolia L. (EETU) and chlorpromazine (CPZ) were tested for their antimicrobial activity alone or in combination with conventional antibiotics against two strains of Escherichia coli (E. coli). The growth of neither E. coli strain was inhibited by the extract. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration values were > or =1 mg/ml for both the strains of E. coli. However, the extract did increase the antimicrobial effects of amikacin, neomycin, and tobramycin. A similar effect of CPZ on amikacin, kanamycin, and tobramycin indicated the involvement of an efflux system in the resistance to these aminoglycosides. Results suggest that extracts from T. ulmifolia could be used as a plant-derived natural product with resistance-modifying activity, constituting a new weapon against bacterial resistance to antibiotics.

In vitro interference of Hyptis martiusii Benth. & chlorpromazine against an aminoglycoside-resistant Escherichia coli.

The antibacterial and synergistic activity of the ethanol extract from Hyptis martiusii Benth. was assayed by microdillution. The growth of two isolates of Escherichia coli tested was inhibited by the extract. The minimum inhibitory and minimum bactericidal concentrations (MIC and MBC) values ranged from 512 and >1024 microg/ml for the E. coli 27 and 1024 and > 1024 microg/ml for the E. coli ATCC8539, respectively. A synergism between this extract and all aminoglycosides assayed was demonstrated. In the same form synergism between chlorpromazine and kanamycin, amikacin and tobramycin was observed, indicating the involvement of an efflux system. Extracts from H. martiusii could be used as a source of plant derived natural products with modifying antibiotic activity and these products may interact and affect multidrug resistance systems (MDR) as efflux pumps.

Herbal therapy associated with antibiotic therapy: potentiation of the antibiotic activity against methicillin--resistant Staphylococcus aureus by Turnera ulmifolia L.

BACKGROUND: Staphylococcus genus is widely spread in nature being part of the indigenous microbiota of skin and mucosa of animal and birds. Some Staphylococcus species are frequently recognized as etiological agents of many animal and human opportunistic infections This is the first report testing the antibiotic resistance-modifying activity of Turnera ulmifolia against methicillin-resistant Staphylococcus aureus--MRSA strain. METHODS: In this study an ethanol extract of Turnera ulmifolia L. and chlorpromazine were tested for their antimicrobial activity alone or in combination with aminoglycosides against an MRSA strain. RESULTS: The synergism of the ethanol extract and aminoglycosides were verified using microdillution method. A synergistic effect of this extract on gentamicin and kanamycin was demonstrated. Similarly, a potentiating effect of chlorpromazine on kanamycin, gentamicin and neomycin, indicating the involvement of an efflux system in the resistance to these aminoglycosides. CONCLUSION: It is therefore suggested that extracts from Turnera ulmifolia could be used as a source of plant-derived natural products with resistance-modifying activity, constituting a new weapon against the problem of bacterial resistance to antibiotics demonstrated in MRSA strains.

Potentiating effect of Mentha arvensis and chlorpromazine in the resistance to aminoglycosides of methicillin-resistant Staphylococcus aureus.

BACKGROUND: This is the first report testing the antibiotic resistance-modifying activity of Mentha arvensis against MRSA (methicillin-resistant Staphylococcus aureus). MATERIALS AND METHODS: In this study an ethanol extract of Mentha arvensis L. and chlorpromazine were tested for their antimicrobial activity alone or in combination with conventional antibiotics against MRSA strains. RESULTS: A potentiating effect of this extract on gentamicin, kanamycin and neomycin was demonstrated. Similarly, a potentiating effect of chlorpromazine on the same aminoglycosides was observed, indicating the involvement of an efflux system in the resistance to these antibiotics. CONCLUSION: It is therefore suggested that extracts from M. arvensis could be used as a source of plant-derived natural products with resistance-modifying activity, such as in the case of aminoglycosides, constituting a new weapon against bacterial resistance to antibiotics, as with chlorpromazine.

Molecular ageing in progeroid syndromes: Hutchinson-Gilford progeria syndrome as a model.

Hutchinson-Gilford progeria syndrome (HGPS) is a rare premature aging disorder that belongs to a group of conditions called laminopathies which affect nuclear lamins. Mutations in two genes, LMNA and ZMPSTE24, have been found in patients with HGPS. The p.G608G LMNA mutation is the most commonly reported mutation. The aim of this work was to compile a comprehensive literature review of the clinical features and genetic mutations and mechanisms of this syndrome as a contribution to health care workers. This review shows the necessity of a more detailed clinical identification of Hutchinson-Gilford progeria syndrome and the need for more studies on the pharmacologic and pharmacogenomic approach to this syndrome.

Modulation of drug resistance in Staphylococcus aureus by a kaempferol glycoside from Herissantia tiubae (Malvaceae).

In an ongoing project to evaluate natural compounds isolated from plants from the Brazilian biodiversity as modulators of antibiotic resistance, kaempferol-3-O-beta-d-(6''-E-p-coumaroyl) glucopyranoside (tiliroside), isolated from Herissantia tiubae (Malvaceae) was investigated using the strain SA-1199B of Staphylococcus aureus, which overexpresses the norA gene encoding the NorA efflux protein which extrudes hydrophilic fluorquinolones and some biocides, such as benzalkonium chloride, cetrimide, acriflavine and ethidium bromide. The minimum inhibitory concentrations (MICs) of the antibiotics and biocides were determined by the microdilution assay in the absence and in the presence of sub-inhibitory concentration of tiliroside. Although tiliroside did not display relevant antibacterial activity (MIC = 256 microg/mL), it modulated the activity of antibiotics, i.e. in combination with antibiotics a reduction in the MIC was observed for norfloxacin (16-fold), ciprofloxacin (16-fold), lomefloxacin (four-fold) and ofloxacin (two-fold), and an impressive reduction in the MICs for the biocides (up to 128-fold). The results presented here represent the first report of a kaempferol glycoside as a putative efflux pump inhibitor in bacteria. The present finding indicates that H. tiubae (and broadly Malvaceae) could serve as a source of plant-derived natural products that modulate bacterial resistance, i.e. a source of potential adjuvants of antibiotics.

Pulmonary bacterial pathogens in cystic fibrosis patients and antibiotic therapy: a tool for the health workers.

Cystic fibrosis is the most common and best known genetic disease involving a defect in transepithelial Cl- transport by mutations in the CF gene on chromosome 7, which codes for the cystic fibrosis transmembrane conductance regulator protein (CFTR). The most serious symptoms are observed in the lungs, augmenting the risk of bacterial infection. The objective of this review was to describe the bacterial pathogens colonizing patients with cystic fibrosis. A systematic search was conducted using the international bibliographic databanks SCIELO, HIGHWIRE, PUBMED, SCIRUS and LILACS to provide a useful and practical review for healthcare workers to make them aware of these microorganisms. Today, B. cepacia, P. aeruginosa and S. aureus are the most important infectious agents in cystic fibrosis patients. However, healthcare professionals must pay attention to emerging infectious agents in these patients, because they represent a potentially serious future problem. Therefore, these pathogens should be pointed out as a risk to these patients, and hospitals all over the world must be prepared to detect and combat these bacteria.

Enhancement of the antibiotic activity against a multiresistant Escherichia coli by Mentha arvensis L. and chlorpromazine.

BACKGROUND: This is the first report testing the antibiotic resistance-modifying activity of Mentha arvensis. METHODS: In this study an ethanol extract of M. arvensis L. and chlorpromazine were tested for their antimicrobial activity alone or in combination with conventional antibiotics against strains of Escherichia coli. RESULTS: The growth of two E. coli strains tested was not inhibited by the extract. The minimum inhibitory concentration and minimal bactericide concentration values were >or=1 mg/ml for both strains of E. coli used. A potentiating effect of this extract on gentamicin was demonstrated. Similarly, there was a potentiating effect of chlorpromazine on kanamycin, amikacin and tobramycin, indicating the involvement of an efflux system in the resistance to these aminoglycosides. CONCLUSIONS: It is therefore suggested that extracts from M. arvensis could be used as a source of plant-derived natural products with resistance-modifying activity, such as in the case of gentamicin, constituting a new weapon against bacterial resistance to antibiotics, as with chlorpromazine.

Composição química e modulação da resistência bacteriana a drogas do óleo essencial das folhas de Rollinia leptopetala R. E. Fries / Chemical composition and modulation of bacterial drug resistance of the essential oil from the leaves of Rollinia leptopetala R. E. Fries

O óleo essencial das folhasde Rollinia leptopetala foi obtido por hidrodestilação em aparelho de Clevenger e a sua composição química foi analisada através de CG-EM. Com essa técnica, foi possível identificar 22 constituintes em uma mistura complexa demonoterpenos (54,5 por cento) e sesquiterpenos (45,5 por cento). O principal componente encontradonas folhas foi o biciclogermacreno (22,47 por cento). O óleo essencial foi avaliado numa linhagem de Staphylococcus aureus portadora de bomba de efluxo responsável pela resistência norfloxacino. Embora o óleo essencial não tenha apresentado atividade antibacteriana relevante in vitro, ele apresentou atividade moduladora da resistência, ou seja, em combinação com o norfloxacino observou-se uma redução de 4x na concentração inibitória mínima do antibiótico, indicando inibição de bomba de efluxo.

The essential oil from the leaves of Rollinia leptopetala was obtained by hydrodistillation in Clevenger's apparatus and its chemical composition was analyzed by GC-MS. With this technique could be identified 22 constituents in a complex mixture of monoterpenes (54.5 percent) and sesquiterpenes (45.5 percent). The main component found in the leaves was the bicyclogermacrene (22.47 percent). The essential oil was assayed against a strain of Staphylococcus aureus possessing efflux mechanism of resistance to norfloxacin. Although the essential oil did not display relevant antibacterial activity in vitro, it modulated the activity of the norfloxacin, i.e. in combination with the antibiotic it was observed a fourfold reduction in the minimum inhibitory concentration for norfloxacin, indicating inhibition of efflux pump.