RESUMO
Acinetobacter baumannii is an opportunistic pathogen associated with increased morbidity and mortality in Healthcare-associated infections (HAI). Combination antimicrobial therapy, meropenem, amikacin and colistin, has been used as an alternative in multidrug-resistant (MDR) A. baumannii infections due to reduced treatment options. However, these combinations are not always effective and exhibit high toxicity. Empiric therapy of intravenous immunoglobulin (IVIG) associated with antimicrobials has shown promising results in bacterial infections, considering the immunomodulatory action of IVIG. Thus, the aim of this study was to determine the combined antimicrobial action and to describe the ultrastructural changes caused in ten MDR A. baumannii isolates submitted to IVIG alone and in combination with colistin, meropenem and amikacin. Minimum Inhibitory Concentration (MIC) of antimicrobials and checkerboard were determined. Isolates were submitted to 4 mg/mL of IVIG alone and in combination with different synergistic sub-MIC of antimicrobials tested, and processed for scanning electron microscopy. Nine bacterial isolates showed meropenem-resistant, two isolates had colistin-intermediate, and four isolates were considered intermediate to amikacin. Synergism in five isolates for meropenem/amikacin and meropenem/colistin were observed. Bacterial cells submitted to IVIG and meropenem, amikacin and colistin presented several ultrastructural changes, such as cell elongation and rupture, membrane roughness, incomplete cell division, cell surface "bubbles" and "depression". A. baumannii isolates presented high resistance to meropenem and synergism among evaluated antimicrobials. In addition, it was possible to verify in vitro that IVIG associated with meropenem, amikacin and colistin is a promising alternative for MDR A. baumannii infections. Thus, these data support the continued empirical use and stimulate in vivo analyzes with IVIG to search for new therapeutic options for HAI.
Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Infecções por Acinetobacter/tratamento farmacológico , Amicacina/farmacologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Colistina/farmacologia , Farmacorresistência Bacteriana Múltipla , Sinergismo Farmacológico , Humanos , Imunoglobulinas Intravenosas , Meropeném/farmacologia , Testes de Sensibilidade MicrobianaRESUMO
Natural products have been used to treat various infections; however, the development of antimicrobials has made natural products in disuse. Riparin I, II and III are natural alkamide isolated from Aniba riparia (Ness) Mez (Lauraceae), that exhibit economic importance and it is used in traditional medicine, and popularly known as "louro". This study investigated the cytotoxicity, antimicrobial and antibiofilm activity, and ultrastructural changes in vitro by riparins I, II and III in Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa. We analyzed the cytotoxicity by MTT assay in Vero cells and hemolytic action verified in human erythrocytes. The antimicrobial activity was determined by microdilution in broth against ATCC strains, identifying the susceptible species. Subsequently, only the MDR isolates of sensitive bacterial species were evaluated regarding its biofilm formation and ultrastructural changes. Riparin I presented low cytotoxicity and hemolytic percentage ranging from of 9.01%-12.97%. Only the riparin III that showed antimicrobial activity against MDR clinical isolates, and significant reduction in biofilm formation in S. aureus. Moreover, the riparin III promoted ultrastructural changes in bacterial cells, such as elongated cellular without bacterial septum, cells with a rugged appearance on the cell surface and cytoplasmic material extravasation. As has been noted riparin III has an inhibitory potential against biofilm formation in S. aureus, besides having antimicrobial activity and promoting ultrastructural changes in MDR clinical isolates. Thus, riparin III is an interesting alternative for further studies aiming to develop new therapeutic options.
Assuntos
Farmacorresistência Bacteriana Múltipla , Staphylococcus aureus , Animais , Antibacterianos/farmacologia , Biofilmes , Chlorocebus aethiops , Humanos , Testes de Sensibilidade Microbiana , Células VeroRESUMO
The increase in urbanization and industrialization has contributed to the contamination of different environments by means of xenobiotic compounds, such as heavy metals, causing changes in microbial communities. Among these metals, the Mercury (Hg2+) is one the most prevalent toxic metals for the environment The present study aimed to evaluate the effect of mercury on the formation of biofilm by environmental (collected from urban stream water) and clinical isolates of Klebsiella pneumoniae. In addition, antibiotic resistance, virulence factors, and genetic diversity were investigated. Taxonomic identity of eight isolates (one reference, two clinical, and five environmental isolates) was performed by MALDI-TOF-MS, while the antibiotic susceptibility profile was assessed by the disc diffusion method. The ability to form biofilms was evaluated by culture on Congo red agar and by crystal violet staining. Biofilm structure was analyzed by scanning electron microscopy. The hydrophobicity profile and the presence of the virulence genes cps, fimH, and mrkD was investigated. The presence of merA and its relationship with antimicrobial resistance were also assessed. The identity of all isolates was confirmed by MALDI-TOF-MS, and different profiles of resistance to mercury and antibiotics as well as of biofilm formation were identified for the clinical and environmental isolates. All isolates were hydrophilic and positive for the virulence genes cps, fimH, and mrkD; only the clinical isolate K36-A2 was positive for merA. The diversity of the isolates was confirmed by ERIC-PCR, which revealed high heterogeneity among the isolates. In conclusion, the data demonstrate that the investigated isolates present different responses to exposure to Hg2+ and correspond to distinct populations of K. pneumoniae disseminated in the investigated environment. The data obtained in this work will aid in understanding the mechanisms of survival of this pathogen under adverse conditions.
Assuntos
Biofilmes/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Klebsiella pneumoniae/efeitos dos fármacos , Mercúrio/toxicidade , Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Farmacorresistência Bacteriana/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Hospitais , Humanos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/patogenicidade , Testes de Sensibilidade Microbiana , Fatores de Virulência/genéticaRESUMO
Systemic infections due to Candida tropicalis are conditions which can frequently lead to death. The aim of this report is to describe the features of C. tropicalis biofilm in a patient with catheter-associated fungemia.
Assuntos
Candida tropicalis/isolamento & purificação , Candidíase Invasiva/diagnóstico , Candidíase Invasiva/patologia , Infecções Relacionadas a Cateter/diagnóstico , Infecções Relacionadas a Cateter/patologia , Neoplasias da Língua/complicações , Biofilmes/crescimento & desenvolvimento , Candidíase Invasiva/microbiologia , Infecções Relacionadas a Cateter/microbiologia , Catéteres/microbiologia , Humanos , Microscopia Eletrônica de VarreduraRESUMO
The aim of this study was to characterize the ultrastructural effects caused by ß-lactam antibiotics in Klebsiella pneumoniae isolates. Three K. pneumoniae clinical isolates were selected for the study with resistance profiles for third-generation cephalosporins, aztreonam, and/or imipenem and with different resistance genes for extended-spectrum ß-lactamases (ESBL) or Klebsiella pneumoniae carbapenemase (KPC). Two K. pneumoniae isolates obtained from the microbiota, which were both resistant to amoxicillin and ampicillin, were also analyzed. In accordance with the susceptibility profile, the clinical isolates were subjected to subminimum inhibitory concentrations (sub-MICs) of cefotaxime, ceftazidime, aztreonam, and imipenem and the isolates from the microbiota to ampicillin and amoxicillin, for analysis by means of scanning and transmission electron microscopy. The K. pneumoniae isolates showed different morphological and ultrastructural changes after subjection to ß-lactams tested at different concentrations, such as cell filamentation, loss of cytoplasmic material, and deformation of dividing septa. Our results demonstrate that K. pneumoniae isolates harboring different genes that encode for ß-lactamases show cell alterations when subjected to different ß-lactam antibiotics, thus suggesting that they possess residual activity in vitro, despite the phenotypic resistance presented in the isolates analyzed.
Assuntos
Antibacterianos/farmacologia , Genes Bacterianos , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/ultraestrutura , Microbiota/efeitos dos fármacos , beta-Lactamases/genética , beta-Lactamas/farmacologia , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Testes de Sensibilidade Microbiana , Análise de Sequência de DNARESUMO
Candida species resistant to fluconazole have raised concern in the scientific medical community due to high mortality in patients with invasive disease. In developing countries, such as Brazil, fluconazole is the most commonly used antifungal, and alternative treatments are expensive or not readily available. Furthermore, the occurrence of biofilms is common, coupled with their inherent resistance to antifungal therapies and the host's immune system, these microbial communities have contributed to making infections caused by these yeasts an enormous clinical challenge. Therefore, there is an urgent need to develop alternative medicines, which surpass the effectiveness of already used therapies, but which are also effective against biofilms. Therefore, the present study aimed to describe for the first time the antifungal and antibiofilm action of the derivative 2-amino-5,6,7,8-tetrahydro-4 H-cyclohepta[b]thiophene-3-isopropyl carboxylate (2AT) against clinical strains of Candida spp. resistant to fluconazole (FLZ). When determining the minimum inhibitory concentrations (MIC), it was found that the compound has antifungal action at concentrations of 100 to 200 µg/mL, resulting in 100% inhibition of yeast cells. Its synergistic effect with the drug FLZ was also observed. The antibiofilm action of the compound in subinhibitory concentrations was detected, alone and in association with FLZ. Moreover, using scanning electron microscopy, it was observed that the compound 2AT in isolation was capable of causing significant ultrastructural changes in Candida. Additionally, it was also demonstrated that the compound 2AT acts by inducing characteristics compatible with apoptosis in these yeasts, such as chromatin condensation, when visualized by transmission electron microscopy, indicating the possible mechanism of action of this molecule. Furthermore, the compound did not exhibit toxicity in J774 macrophage cells up to a concentration of 4000 µg/mL. In this study, we identify the 2AT derivative as a future alternative for invasive candidiasis therapy, in addition, we highlighted the promise of a strategy combined with fluconazole in combating Candida infections, especially in cases of resistant isolates.
RESUMO
This study aimed to determine the composition of the essential oil of Mentha x villosa and to evaluate its biological effects in vitro on adult worms of S. mansoni. Rotundifolone (70.96 %), limonene (8.75 %), trans-caryophyllene (1.46 %), and ß-pinene (0.81 %) were shown to be the major constituents of this oil. Adult worms of S. mansoni were incubated with different concentrations of the essential oil (1, 10, 100, 250, 500, and 1000 µg/mL) and of its constituents rotundifolone (0.7, 3.54, 7.09, 70.96, 177.4, 354.8, and 700.96 µg/mL), limonene (43.75 µg/mL), trans-caryophyllene (7.3 µg/mL), and ß-pinene (4.03 µg/mL). No schistosomicidal activity was identified at the trans-caryophyllene and ß-pinene concentrations studied. However, use of the essential oil (10 µg/mL), rotundifolone (7.09 µg/mL), and limonene (43.75 µg/mL) resulted in decreased worm motility continuing until 96 hours of observation. At higher concentrations (100 and 70.96 µg/mL, respectively), both the essential oil and rotundifolone caused mortality among adult worms of S. mansoni. The positive control praziquantel caused the death of all parasites after 24 h of evaluation. The results from this study suggest that the essential oil of Mentha x villosa presents schistosomicidal efficacy.
Assuntos
Mentha/química , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Esquistossomicidas/farmacologia , Animais , Monoterpenos Bicíclicos , Compostos Bicíclicos com Pontes/análise , Compostos Bicíclicos com Pontes/farmacologia , Cicloexenos/análise , Cicloexenos/farmacologia , Limoneno , Monoterpenos/análise , Monoterpenos/farmacologia , Óleos Voláteis/química , Extratos Vegetais/química , Sesquiterpenos Policíclicos , Sesquiterpenos/análise , Sesquiterpenos/farmacologia , Terpenos/análise , Terpenos/farmacologiaRESUMO
The high incidence of multidrug-resistant (MDR) Acinetobacter baumannii has been a challenge for health worldwide, due to the reduction of therapeutic options, making the use of antimicrobial combinations necessary for the treatment, such as meropenem, amikacin, and colistin. Antibodies against bacterial species, mainly immunoglobulins G (IgG), are produced for acting as effector mechanisms (neutralization, opsonization, phagocytosis, and complement system activation). Some studies have demonstrated promising results of IgG in combination with antimicrobial preparations against bacterial infections, in which the direct action of IgG has restored the immune system balance. Serious problem caused by the increase of MDR A. baumannii isolates results in a constant search for therapeutic alternatives to defeat these infections. However, this study aims to verify in vitro the phagocytosis rate of the A. baumannii-infected human monocytes, as well as to analyze possible morphological changes induced by intravenous immunoglobulin G (IVIG) with human serum in association with antimicrobials. The phagocytosis rate and bacterial cell binding capacity of IVIG were determined for two A. baumannii isolates submitted to 4 mg/mL of human IVIG alone and in combination with different sub-minimum inhibitory concentrations (sub-MICs) of meropenem, amikacin, and colistin and processed for indirect immunofluorescence. Subsequently, these isolates were resubmitted and coupled with human serum and processed for scanning electron microscopy. There was no statistical difference for phagocytosis rates in the isolates tested. Bacterial isolates showed alterations in cell morphology when exposed to IVIG/human serum alone and in combination with antimicrobials such as alteration in shape, wrinkling, membrane depression, and especially cell rupture with extravasation of cytoplasmic material. The isolates visually differed in the IVIG binding to the bacterial cell, with higher fluorescence intensity, which corresponds to the highest IVIG binding, in the isolate more sensitive to meropenem, amikacin, and colistin. No differences between treatments were observed in the IVIG binding to the bacterial cell. The combined action of IVIG with meropenem, amikacin, and colistin against A. baumannii MDR isolates induced several bacterial cell damages. And when associated with human serum, a massive destruction of cells can be observed. These results may suggest the analysis of the use of IgG preparations for the treatment of A. baumannii MDR infections.
Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Anti-Infecciosos , Humanos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Imunoglobulinas Intravenosas/farmacologia , Imunoglobulinas Intravenosas/uso terapêutico , Meropeném/farmacologia , Meropeném/uso terapêutico , Colistina/farmacologia , Amicacina/farmacologia , Amicacina/uso terapêutico , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/microbiologia , Anti-Infecciosos/farmacologia , Testes de Sensibilidade Microbiana , Farmacorresistência Bacteriana Múltipla , Sinergismo FarmacológicoRESUMO
The aim of this study was to determine the prevalence of the bla (SHV) gene in Klebsiella pneumoniae isolates from hospital and community infections and from the normal microbiota of healthy individuals in Recife, PE, Brazil. Fifty-two K. pneumoniae isolates were analyzed regarding the presence of the bla (SHV) gene, using PCR, and eight isolates were analyzed by DNA sequencing. This gene was detected in 16 isolates from hospital infections, four from community infections, and nine from the normal microbiota. This was the first study to find the bla (SHV) gene in K. pneumoniae isolates from the normal microbiota. Through DNA sequencing of eight K. pneumoniae isolates from hospital and community infections, with a resistance phenotype indicative of extended-spectrum ß-lactamase production, a new SHV variant named SHV-122 was found. We also detected the presence of bla (SHV-1), bla (SHV-11), bla (SHV-28), and bla (SHV-108). The results show that in Recife, Brazil, K. pneumoniae isolates that presented resistance to oxyimino-ß-lactams had high prevalence and diversity of the bla (SHV) gene. We also conclude that there was a high presence of the bla (SHV) gene among isolates from the normal microbiota of healthy individuals.
Assuntos
Proteínas de Bactérias/genética , Infecções Comunitárias Adquiridas/microbiologia , Infecção Hospitalar/microbiologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/isolamento & purificação , beta-Lactamases/genética , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Técnicas de Tipagem Bacteriana , Brasil/epidemiologia , Infecções Comunitárias Adquiridas/epidemiologia , Infecção Hospitalar/epidemiologia , Farmacorresistência Bacteriana , Humanos , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , beta-Lactamases/metabolismoRESUMO
Twenty-eight Klebsiella pneumoniae clinical isolates that exhibited an extended-spectrum cephalosporin-resistance profile from a city in the Northeast of Brazil were analysed by PCR and DNA sequencing in order to determine the occurrence of blaCTX-M genes and class 1 integrons. We determined the occurrence of the blaCTX-M-2 gene in six K. pneumoniae isolates and describe the first detection of the blaCTX-M-28 gene in South America. Seven isolates carried class 1 integrons. Partial sequencing analysis of the 5'-3'CS variable region in the class 1 integrons of three isolates revealed the presence of aadA1, blaOXA-2 and dfr22 gene cassettes.
Assuntos
DNA Bacteriano/genética , Integrons/genética , Klebsiella pneumoniae/genética , beta-Lactamases/genética , Antibacterianos/farmacologia , Sequência de Bases , Brasil , Farmacorresistência Bacteriana/genética , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Análise de Sequência de DNARESUMO
OBJECTIVES: Multidrug-resistant Klebsiella pneumoniae carrying blaNDM-1 and blaKPC-2 genes are a worldwide concern for which combination antimicrobial therapy may be the only viable option. The aim of this study was to investigate the in vitro activity of combinations of polymyxin B (PMB) with meropenem (MEM), amikacin (AMK) and gentamicin (GEN) at subinhibitory concentrations against two K. pneumoniae clinical isolates co-harbouring blaNDM-1, blaKPC-2 and aminoglycoside-modifying enzymes and resistant to PMB. METHODS: Synergy and bactericidal activity were evaluated by chequerboard and time-kill assays against two PMB-resistantK. pneumoniae clinical isolates carrying the blaNDM-1, blaKPC-2, aac(3)-IIa, aac(6')-Ib, aph(3')-VI and ant(2'')-Ia genes. Five combinations of PMB, MEM, AMK and GEN were evaluated. RESULTS: The PMB/MEM and PMB/AMK combinations proved to be the best options against isolate K7R2, mainly because they demonstrated bactericidal activity when using subinhibitory concentrations of these antimicrobials. However, none of the studied combinations was bactericidal against isolate K11R2. CONCLUSION: The combinations used in this study showed synergy against NDM-and KPC-producing isolates but, given their bactericidal activity, the combinations of PMB/MEM and PMB/AMK were the most active against one isolate. It can also be concluded that the antimicrobials to which the bacteria were resistant could form part of combination therapy.
Assuntos
Klebsiella pneumoniae , Polimixina B , Amicacina/farmacologia , Aminoglicosídeos , Gentamicinas , Klebsiella pneumoniae/genética , Meropeném/farmacologia , Testes de Sensibilidade Microbiana , Polimixina B/farmacologia , beta-LactamasesRESUMO
OBJECTIVES: Carbapenemase-producing Enterobacterales are frequently involved in healthcare-associated infections worldwide. The objectives of this study were to investigate (i) the frequency of the main genes encoding carbapenemases, 16S rRNA methylases and aminoglycoside-modifying enzymes (AMEs) as well as the mcr gene and (ii) the clonal relationship of enterobacteria isolates resistant to carbapenems and aminoglycosides from colonisation and infection in patients from hospitals in northeastern Brazil. METHODS: Antimicrobial susceptibility was determined using an automated VITEK®2 system. Presence of carbapenemase, AME and 16S rRNA methylase genes as well as the mcr gene was determined by PCR and amplicon sequencing. Genetic variability was determined by ERIC-PCR. RESULTS: A total of 35 isolates resistant to carbapenems and aminoglycosides were selected for this study. Klebsiella pneumoniae was most common (45.7%), followed by Proteus mirabilis (28.6%) and Serratia marcescens (25.7%). AME genes were found in 97.1% of isolates, most commonly aph(3')-VI and aac(6')-Ib. The blaNDM-1 and blaKPC-2 genes were detected in 25.7% and 88.6% of isolates, respectively; five isolates harboured these genes concomitantly. According to the literature, this is the first report of the association of blaNDM-1 and blaKPC-2 in P. mirabilis and S. marcescens in Brazil. The isolates showed a multiclonal profile by ERIC-PCR. CONCLUSION: The emergence of blaNDM-1 associated with blaKPC-2 and AME genes in K. pneumoniae, P. mirabilis and S. marcescens isolates with a multiclonal profile is of concern as this limits therapeutic options. These results should alert medical authorities to establish rigorous detection methods to reduce the spread of these antimicrobial resistance genes.
Assuntos
Klebsiella pneumoniae , Proteus mirabilis , Aminoglicosídeos/farmacologia , Brasil , Humanos , Klebsiella pneumoniae/genética , Testes de Sensibilidade Microbiana , Proteus mirabilis/genética , RNA Ribossômico 16S , Serratia marcescens/genética , beta-LactamasesRESUMO
INTRODUCTION:: Schistosomiasis, a parasitic disease caused by trematode flatworms of the genus Schistosoma, affects more than 200 million people worldwide, and its control is dependent on a single drug, praziquantel. Here, we report the in vitro effect of rotundifolone, a monoterpene isolated from Mentha x villosa (Lamiaceae), on Schistosoma mansoni adult worms. METHODS:: The in vitro effect of rotundifolone on adult Schistosoma mansoni was evaluated by analysis of behavior and mortality and through a scanning electron microscopic analysis of ultrastructural changes in the tegument of the worms. RESULTS:: At concentrations of 3.54 and 7.09µg/mL-1 rotundifolone, no worm mortality was observed at any of the sampling intervals. A minor reduction in movement of the tail, suckers, and gynecophoral canal membrane was observed after 96 h of exposure to 7.09µg/mL-1 rotundifolone. At 70.96µg/mL-1, a lack of movement was observed from 72h onwards and all worms were deemed dead; similar effects were observed at 48h with 177.4µg/mL-1, and at 24h with 354.8µg/mL-1 and 700.96µg/mL-1. Rotundifolone also caused death of all parasites and separation of coupled pairs into individual males and females after 24h at 354.8µg/mL-1. CONCLUSIONS:: The main changes in the tegument induced by the different ROT treatments were: after 24h incubation, bubble lesions spread over the entire body and loss of tubercles occurred in some regions of the ventral region.
Assuntos
Mentha/química , Monoterpenos/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Animais , Feminino , Masculino , Microscopia Eletrônica de Varredura , Monoterpenos/isolamento & purificação , Testes de Sensibilidade Parasitária , Schistosoma mansoni/ultraestruturaRESUMO
The ultrastructural alterations caused by polymyxin B and meropenem and by the association between polymyxin B and meropenem were investigated in two multiresistant isolates of Klebsiella pneumoniae (K3-A2 and K12-A2) carriers of blaKPC-2, coming from infection and colonization in patients in a public hospital in Recife, Brazil. The ultrastructural changes were detected by transmission electron microscopy and scanning. The susceptibility of the isolates to antimicrobials was tested by the disc diffusion method and microdilution in broth. The analysis by electron microscopy showed that the isolates presented morphological and ultrastructural cellular changes when subjected to a clinically relevant concentration of antimicrobials alone or in combination. When subjected to meropenem, they presented retraction of the cytoplasmic material, rupture of the cell wall and extravasation of the cytoplasmic content. When submitted to polymyxin B, the isolates showed condensation of the ribosomes, DNA clotting, cell wall thickening and the presence of membrane compartment. When subjected to polymyxin B and meropenem in combination, the isolates showed a higher intensity of the ultrastructural changes visualized. This is the first report of the ultrastructural changes caused by polymyxin B and meropenem in multiresistant isolates of K. pneumoniae carriers of the blaKPC-2 gene. It should be noted that even when the K. pneumoniae isolates were multiresistant carriers of the blaKPC-2 gene, they underwent important structural change owing to the action of polymyxin B and meropenem.
Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/ultraestrutura , Polimixina B/farmacologia , Tienamicinas/farmacologia , Proteínas de Bactérias/genética , Brasil/epidemiologia , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Humanos , Infecções por Klebsiella/epidemiologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Masculino , Meropeném , Testes de Sensibilidade Microbiana , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , beta-Lactamases/genéticaRESUMO
INTRODUCTION: The essential oil Mentha x villosa (MVEO) has a wide range of actions, including antibacterial, antifungal, antiprotozoal and schistosomicidal actions. The present study aimed to investigate the ultrastructural changes of MVEO on the tegument of adult Schistosoma mansoni. MATERIALS AND METHODS: Different concentrations of MVEO were tested on S. mansoni adult worms in vitro. Ultrastructural changes on the tegument of these adult worms were evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). RESULTS: The MVEO caused the death of all worms at 500 µg mL(-1) after 24 h. After 24h of 500 µg mL(-1) MVEO treatment, bubble lesions were observed over the entire body of worms and they presented loss of tubercles in some regions of the ventral portion. In the evaluation by TEM, S. mansoni adult worms treated with MVEO, 500 µg mL(-1), presented changes in the tegument and vacuoles in the syncytial matrix region. Glycogen granules close to the muscle fibers were visible. CONCLUSION: The ability of MVEO to cause extensive ultrastructural damage to S. mansoni adult worms correlates with its schistosomicidal effects and confirms earlier findings with S. mansoni.
Assuntos
Mentha/química , Óleos Voláteis/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Schistosoma mansoni/ultraestrutura , Esquistossomicidas/farmacologia , Animais , Masculino , Camundongos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de TransmissãoRESUMO
ABSTRACT INTRODUCTION: Schistosomiasis, a parasitic disease caused by trematode flatworms of the genus Schistosoma, affects more than 200 million people worldwide, and its control is dependent on a single drug, praziquantel. Here, we report the in vitro effect of rotundifolone, a monoterpene isolated from Mentha x villosa (Lamiaceae), on Schistosoma mansoni adult worms. METHODS: The in vitro effect of rotundifolone on adult Schistosoma mansoni was evaluated by analysis of behavior and mortality and through a scanning electron microscopic analysis of ultrastructural changes in the tegument of the worms. RESULTS: At concentrations of 3.54 and 7.09μg/mL-1 rotundifolone, no worm mortality was observed at any of the sampling intervals. A minor reduction in movement of the tail, suckers, and gynecophoral canal membrane was observed after 96 h of exposure to 7.09μg/mL-1 rotundifolone. At 70.96μg/mL-1, a lack of movement was observed from 72h onwards and all worms were deemed dead; similar effects were observed at 48h with 177.4μg/mL-1, and at 24h with 354.8μg/mL-1 and 700.96μg/mL-1. Rotundifolone also caused death of all parasites and separation of coupled pairs into individual males and females after 24h at 354.8μg/mL-1. CONCLUSIONS: The main changes in the tegument induced by the different ROT treatments were: after 24h incubation, bubble lesions spread over the entire body and loss of tubercles occurred in some regions of the ventral region.
Assuntos
Animais , Masculino , Feminino , Schistosoma mansoni/efeitos dos fármacos , Mentha/química , Monoterpenos/farmacologia , Schistosoma mansoni/ultraestrutura , Microscopia Eletrônica de Varredura , Testes de Sensibilidade Parasitária , Monoterpenos/isolamento & purificaçãoRESUMO
Introduction: The essential oil Mentha x villosa (MVEO) has a wide range of actions, including antibacterial, antifungal, antiprotozoal and schistosomicidal actions. The present study aimed to investigate the ultrastructural changes of MVEO on the tegument of adult Schistosoma mansoni. Materials and Methods: Different concentrations of MVEO were tested on S. mansoni adult worms in vitro. Ultrastructural changes on the tegument of these adult worms were evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results: The MVEO caused the death of all worms at 500 μg mL-1 after 24 h. After 24h of 500 μg mL-1 MVEO treatment, bubble lesions were observed over the entire body of worms and they presented loss of tubercles in some regions of the ventral portion. In the evaluation by TEM, S. mansoni adult worms treated with MVEO, 500 μg mL-1, presented changes in the tegument and vacuoles in the syncytial matrix region. Glycogen granules close to the muscle fibers were visible. Conclusion: The ability of MVEO to cause extensive ultrastructural damage to S. mansoni adult worms correlates with its schistosomicidal effects and confirms earlier findings with S. mansoni.
Assuntos
Animais , Masculino , Camundongos , Mentha/química , Óleos Voláteis/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Schistosoma mansoni/ultraestrutura , Esquistossomicidas/farmacologia , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de TransmissãoRESUMO
OBJECTIVES: Pseudomonas aeruginosa is an increasingly prevalent opportunistic pathogen in hospital infection cases. Its high resistance rates to many antimicrobials has given this microorganism a relevant role among other highly prevalent bacteria involved in nosocomial infections. This study aimed to analyze epidemiologic characteristics of P. aeruginosa and to evaluate its susceptibility to antimicrobial agents at Hospital das Clínicas of the Universidade Federal de Pernambuco METHODS: A retrospective study was performed based on the registry book of miscellaneous secretions from the bacteriology laboratory of the Hospital das Clínicas involving the period between January and June 2008. Among the secretions registered, were identified the positives samples for P. aeruginosa, whose origin was analyzed, as well as its susceptibility profile to routinely used in our laboratory antimicrobials. RESULTS: The bacteria most frequently isolated from miscellaneous secretions bacteria were P. aeruginosa (26%) and S. aureus (25%). P. aeruginosa was mainly isolated from respiratory infections, with 33% of positive samples for this organism from tracheal secretions and 21% from nasal. The most effective antimicrobials against P. aeruginosa were: amikacin, imipenem, meropenem and aztreonam. CONCLUSIONS: These results show a high prevalence of P. aeruginosa in the Hospital das Clínicas of the Universidade Federal de Pernambuco. Despite featuring high resistance rates to older antimicrobials, as cephalosporins first and second generations and chloramphenicol, this pathogen showed good susceptibility to agents routinely used in this hospital.