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PURPOSE: We evaluated if, during lithotripsy, bacteria may be detected in the irrigation fluid of percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS). The concordance between urine culture from stone fragmentation (SFUC), bladder (BUC), renal pelvic (RPUC) and stone (SC) was analyzed. We also assessed the correlation between variables and cultures and their association with systemic inflammatory response syndrome (SIRS) and of a positive SC. METHODS: We included 107 patients who underwent PCNL (n = 53) and RIRS (n = 54) from January 2017 to May 2018. Samples for RPUC were obtained by renal catheterization. Stone fragments and irrigation fluid sample were sent for culture. RESULTS: SFUC was positive in 17 (15.9%), BUC in 22 (20.6%), RPUC in 26 (24.3%) and SC in 30 patients (28%). The concordance between SFUC and SC was the highest among all cultures: 94.1%. SFUC and SC grew identical microorganisms in 15/17 (88.2%) patients. Out of 17 (15.9%) patients with SIRS, 8 (7.5%) had sepsis. SFUC had the highest PPV and specificity to detect positive SC and SIRS. Previous urinary tract infection, a preoperative nephrostomy, stone diameter and composition, staghorn calculi, PCNL, positive BUC, RPUC and SFUC were predictors of infected stone. Variables that indicate complex stones, complex PCNL and an infection of the upper tract were associated with SIRS. CONCLUSION: SFUC is technically feasible, easy to retrieve and to analyze. The spectrum of SFUC potential application in clinical practice is when is not possible to perform a SC, e.g. complete dusting or during micro-PCNL.
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Bacterias/aislamiento & purificación , Cálculos Renales/cirugía , Cálculos Renales/orina , Riñón/cirugía , Nefrolitotomía Percutánea , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Orina/microbiologíaRESUMEN
Antibiotic resistance is one of the bigger problem of public health: the rise of multi-drug resistant organisms causes a challenge in the treatment of infective diseases. Anti-Candida resistance to conventional antifungal agents has increased in the last period. Our research was intended to evaluate antimicrobial activity of oil macerate (OM) of Helichrysum microphyllum Cambess. subsp. tyrrhenicum Bacch., Brullo & Giusso and OM of Hypericum perforatum subsp. angustifolium against several clinical strains. The study included 30 patients with candidiasis who had not received any antifungal treatment before they were enrolled. A collection of 30 clinical isolates belonging to 5 different species of Candida spp. was selected for this study. The data obtained showed an interesting activity of both Oil Macerate especially against C. krusei and C. parapsilosis. On the contrary, H. microphyllum Oil Macerate has had a better activity than the H.perforatum especially in relation to C. glabrata and C. krusei.
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Antifúngicos/farmacología , Candida/efectos de los fármacos , Candidiasis/microbiología , Helichrysum/química , Hypericum/química , Aceites de Plantas/farmacología , Adulto , Anciano , Anciano de 80 o más Años , Candida/aislamiento & purificación , Candidiasis/tratamiento farmacológico , Farmacorresistencia Fúngica , Femenino , Humanos , Italia , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Adulto JovenRESUMEN
AIMS: The ability of Vibrio alginolyticus strains isolated from Sparus aurata and Dicentrarchus labrax nursery to adhere to epithelial cell lines (Hep-2 and Caco-2), fish mucus and their ability to form a biofilm on different surfaces (glass, polystyrene, polyethylene and polyvinyl-chloride) was investigated in this study. METHODS AND RESULTS: The extracellular products were rich in enzymes and the strains were haemolytic on Wagatsuma agar and possessed several hydrolytic exoenzymes such as proteases, DNase and lipases. Most strains tested were multiresistant to the 17 antibiotics tested including those used in the farm to treat vibriosis. CONCLUSIONS: These bacteria were able to form a biofilm on all the surfaces tested and the cell density was the highest on the PVC surface followed by that on the glass slides, polystyrene and the polyethylene surface. More than 50% of the tested strains were adhesive to the epithelial cell lines (Hep-2 and Caco-2). SIGNIFICANCE AND IMPACT OF THE STUDY: These properties allow these bacteria to survive, proliferate and persist in all stages of fish rearing nursery even after seawater treatment with UV light.
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Adhesión Bacteriana , Vibrio alginolyticus/fisiología , Animales , Acuicultura , Lubina , Biopelículas/crecimiento & desarrollo , Células CACO-2/microbiología , Línea Celular Tumoral , Electroforesis en Gel de Agar , Células Epiteliales/microbiología , Vidrio , Humanos , Microscopía de Fuerza Atómica , Moco/microbiología , Polietileno , Poliestirenos , Dorada , Agua de Mar , Vibrio alginolyticus/clasificación , Vibrio alginolyticus/genéticaRESUMEN
Increasing demand drives the expansion of criteria for kidney donation, and nephrolithiasis is now considered a relative contraindication. We report for the first time a case of intra-operative, postperfusion kidney allograft micronephrolithotomy. A 64-year-old man with end-stage renal disease secondary to Alport syndrome underwent primary deceased donor kidney transplantation at our center. Pre-operative ultrasound of the donor identified a 7-mm calculus in the anterior, lower pole calyx. The kidney was extra-peritoneally implanted in the right iliac fossa and reperfused homogenously. Stone retrieval with a flexible ureteroscope failed due to the narrow calyceal infundibulum. Instead, the calculus was removed using the micropercutaneous nephrolithotomy system under ultrasonographic guidance. The calyx was punctured using a 4.85 Fr needle and the stone was fragmented to dust using a Holmium laser. No bleeding was observed. The post-operative course was uneventful. Outpatient follow up demonstrated good function of the graft which was stone free on ultrasound. Postperfusion micropercutaneous nephrolithotomy for kidney allograft calculi offers a safe and feasible option when pre-operative or intra-operative retrograde intrarenal surgery fails.
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Cálculos Renales/cirugía , Trasplante de Riñón/métodos , Nefrotomía/métodos , Trasplantes/patología , Trasplantes/cirugía , Adulto , Anciano , Femenino , Humanos , Masculino , Trasplante Homólogo , Ultrasonografía IntervencionalRESUMEN
INTRODUCTION: Antibiotics that suppress Propionibacterium acnes are the standard treatment for acne but are becoming less effective, due to the appearance of antibiotic-resistant strains. Many plants are known to have innate antimicrobial action and can be used as alternatives to antibiotics; thus, it is necessary to prove their effectiveness in vivo. This study aimed to evaluate the anti-acne efficacy of a new cream based on three natural extracts, comparing it to erythromycin cream and placebo. PATIENTS AND METHODS: Sixty patients with mild to moderate acne vulgaris were randomly divided into three groups: treated with cream containing 20% propolis, 3% "tea tree oil", and 10% "Aloe vera" (PTAC) (n=20); or with 3 % erythromycin cream (ERC) (n=20); or with placebo (n=20). At baseline, after 15 and 30 days, investigators evaluated response to treatment by counting acne lesions through noninvasive measurements and macrophotography. RESULTS: All the clinical and instrumental values studied were statistically different from placebo except for sebometry, pHmetry, and erythema index values, measured on healthy skin. Unlike in the placebo group, papular and scar lesions showed high erythema reduction after 15 and 30 days of PTAC and ERC application. CONCLUSION: The PTAC formulation was better than ERC in reducing erythema scars, acne severity index, and total lesion count.
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The antimicrobial activity of Austroeupatorium inulaefolium (H.B.K.) essential oil was studied in different pathogens species and its cytotoxicity activity was determinated on different cellular lines. Despite the good antibacterial activity of A. inulaefolium, it has been cytotoxic at low concentrations. Consequently it might be interesting to determine the antimicrobial activity and cytotoxicity of the major compounds of this essential oil.
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Antiinfecciosos/farmacología , Asteraceae/química , Animales , Antibacterianos/aislamiento & purificación , Antiinfecciosos/aislamiento & purificación , Muerte Celular/efectos de los fármacos , Línea Celular , Humanos , Pruebas de Sensibilidad Microbiana , Aceites Volátiles/análisisRESUMEN
Lavender is an aromatic evergreen shrub diffused in the Mediterranean basin appreciated since antiquity. The genus Lavandula is part of Lamiaceae family and includes more than 20 species, among which true lavender (L. vera D.C. or L. angustifolia Miller.) and spike lavender (L. latifolia Medikus); there are also numerous hybrids known as lavandins (L. hybrida Rev.). L. vera, spike lavender and several hybrids are the most intensely used breeding species for the production of essential oils. Lavender and lavandin essential oils have been applied in food, pharmaceutical and other agro industries as biological products. In their chemical composition, terpenes linalool and linalyl acetate along with terpenoids such as 1,8-cineole are mostly responsible for biological and therapeutic activities. This study evaluates cytotoxic activity of essential oils derived from four lavender species on human epithelial colorectal adenocarcinoma cells. Analysis of pre- and post-treatment cell morphology has been performed using scanning electron microscope.
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Lavandula/química , Aceites Volátiles/química , Aceites Volátiles/farmacología , Monoterpenos Acíclicos , Células CACO-2 , Ciclohexanoles/análisis , Ciclohexanoles/farmacología , Eucaliptol , Humanos , Microscopía Electrónica de Rastreo , Monoterpenos/análisis , Monoterpenos/farmacología , Aceites Volátiles/análisisRESUMEN
INTRODUCTION: The Enterobacter cloacae is a microorganism found in the intestinal flora of the majority of animals, including humans. Primary infections caused by E. cloacae are rare in immunocompetent patients, but are very common in hospital settings in newborns and immunocompromised patients, and can be aggravated by the insurgence of antibiotic resistance. The incidence of periprosthetic hip infections is just below 2%. CASE PRESENTATION: A 76year old woman with multiple comorbidities underwent surgical implantation of intermediary total hip prosthesis of the left hip, in a different health facility, in February 2014, after the basicervical fracture of the upper femur extremity due to trauma. After an episode of dislocation of the prosthetic implant, in September 2014, she underwent a surgical operation to implant the acetabular component. A month later not in our facility, following a re-hospitalization for the dislocation of the arthroprosthesis, an infection from E. cloacae complex was discovered. After 2 years of chronic infection she came to our attention; the clinical picture featured coxalgia and secreting fistula in the surgical wound. Following a specific antibiotic therapy, carried out intravenously over the course of a month, we decided to intervene removing the left hip arthroprosthesis and placing an antibiotic spacer following the direction deduced from the antibiogram study of August 2016. CONCLUSION: The patient was hospitalized in our facility and 2 months later she underwent another operation to remove the antibiotic spacer and to place a new total hip arthroprosthesis. Multiple swabs showed the complete healing from the infection, which was confirmed a couple of months later.
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Symbiotic N2 fixation is one of the main processes that introduces N into terrestrial ecosystems. As such, it may be crucial for the sequestration of the extra C available in a world of continuously increasing atmospheric CO2 partial pressure (pCO2). The effect of elevated pCO2 (60 Pa) on symbiotic N2 fixation (15N-isotope dilution method) was investigated using Free-Air-CO2-Enrichment technology over a period of 3 years. Trifolium repens was cultivated either alone or together with Lolium perenne (a nonfixing reference crop) in mixed swards. Two different N fertilization levels and defoliation frequencies were applied. The total N yield increased consistently and the percentage of plant N derived from symbiotic N2 fixation increased significantly in T. repens under elevated pCO2. All additionally assimilated N was derived from symbiotic N2 fixation, not from the soil. In the mixtures exposed to elevated pCO2, an increased amount of symbiotically fixed N (+7.8, 8.2, and 6.2 g m-2 a-1 in 1993, 1994, and 1995, respectively) was introduced into the system. Increased N2 fixation is a competitive advantage for T. repens in mixed swards with pasture grasses and may be a crucial factor in maintaining the C:N ratio in the ecosystem as a whole.
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We determined prospectively during a 12-month period the incidence, clinical characteristics and outcome of Yersinia enterocolitica infection in 144 thalassemic patients (mean age, 12.8 years) and compared them with 100 controls (mean age, 12.1 years). Symptomatic Y. enterocolitica infection occurred in 14 (10%) of the thalassemic patients and in 2 (2%) controls (P = 0.017). Of the 14 thalassemic patients 5 (36%) had septicemia and 9 (64%) had focal infection (enteritis in 8 and tonsillitis in 1). One control patient had acute enteritis and the other had tonsillitis. All isolates from these patients belonged to pathogenic phenotypes of Y. enterocolitica. Pending culture results symptomatic thalassemic patients discontinued treatment with deferoxamine and were treated with intravenous antibiotic therapy. Patients with the ultimate diagnosis of focal Y. enterocolitica infection continued treatment with intramuscular ceftriaxone or intravenous trimethoprim/sulfamethoxazole (TMP/SMX) for 7 days, whereas those with septicemia continued treatment with intravenous TMP/SMX for 14 days. The outcome was favorable in all 14 thalassemic patients. We conclude that Y. enterocolitica is a significant cause of morbidity in our patients with thalassemia and that prompt antibiotic therapy might prevent life-threatening conditions as well as a complicated course with long term sequelae.
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Antibacterianos/uso terapéutico , Talasemia/complicaciones , Yersiniosis/complicaciones , Yersinia enterocolitica , Adolescente , Adulto , Ceftriaxona/uso terapéutico , Cefalosporinas/uso terapéutico , Niño , Preescolar , Femenino , Humanos , Incidencia , Lactante , Masculino , Estudios Prospectivos , Factores de Riesgo , Resultado del Tratamiento , Combinación Trimetoprim y Sulfametoxazol/uso terapéutico , Yersiniosis/tratamiento farmacológico , Yersiniosis/epidemiología , Yersiniosis/fisiopatología , Yersinia enterocolitica/efectos de los fármacos , Yersinia enterocolitica/aislamiento & purificaciónRESUMEN
Sequence analysis of different fragments that hybridized with a 4.5-kb EcoRI fragment originally cloned from Enterococcus hirae ATCC 9790 showed 66% homology to IS-like sequences found in staphylococci and lactococci. We tested several enterococcal ATCC strains and found that only E. hirae ATCC 9790 and Enterococcus faecium ATCC 19434 hybridized with the IS-like sequence. Moreover, we wanted to investigate the dissemination of this new IS among E. faecium strains. We analyzed 131 clinical E. faecium isolated in Italy and the USA for the presence of the IS and we found its presence in more than 63% of the isolates. The hybridization patterns obtained vary considerably between unrelated strains and allow further classification among ribotype-grouped species.
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Enterococcus faecium/genética , Enterococcus/genética , Secuencia de Bases , Dermatoglifia del ADN , Enterococcus/clasificación , Datos de Secuencia Molecular , Secuencias Repetitivas de Ácidos NucleicosRESUMEN
Enterococci are widely distributed in the environment; within the human body, they are normal commensals of the oral cavity, gastrointestinal tract and vagina. In recent years, enterococci have become one of the most frequent causes of acquired nosocomial infections worldwide. The molecular mechanism of virulence of these bacteria is still not completely understood. The aims of this work were to characterize phenotypically 47 isolates of Enterococcus faecalis and Enterococcus faecium collected in Sardinia (Italy) by their abilities to adhere to different epithelial cell lines (Vero and Caco-2 cells) and to associate their phenotypes with the presence of known virulence genes detected within their genomes by PCR. The following genes were amplified: AS (aggregation substance), esp (surface protein gene), ace (accessory colonization factor), efaA (E. faecalis endocarditis antigen) and gelE (gelatinase). The virulence genes were detected in E. faecalis isolates only, with the exception of esp, which was found in both species. The phenotypic and genotypic results were also compared with the susceptibility of isolates to various antibiotics.
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Enterococcus faecalis/patogenicidad , Enterococcus faecium/patogenicidad , Infecciones por Bacterias Grampositivas/microbiología , Antígenos Bacterianos/genética , Adhesión Bacteriana , Proteínas Bacterianas/genética , Biopelículas/crecimiento & desarrollo , Proteínas Portadoras/genética , Farmacorresistencia Bacteriana , Enterococcus faecalis/efectos de los fármacos , Enterococcus faecalis/genética , Enterococcus faecium/efectos de los fármacos , Enterococcus faecium/genética , Femenino , Gelatinasas/genética , Humanos , Italia , Masculino , Proteínas de la Membrana/genética , Pruebas de Sensibilidad Microbiana , Fenotipo , Ribotipificación , Virulencia/genéticaRESUMEN
OBJECTIVE: Human herpesvirus 8 (HHV8) is believed to be transmitted mainly by sexual contact; epidemiological data from Africa show, however, that non-sexual transmission routes may also play an important role. To evaluate better the distribution of HHV8 infection in the Mediterranean area, we performed an age-specific seroprevalence study. METHODS: Sera were collected from subjects from different geographical areas. The sera were analyzed by immunofluorescence assay (IFA) and enzyme-linked immunosorbent assay (ELISA). A total of 1083 patients were studied, 667 patients from various regions of Italy and 416 from Albania. The patients were stratified into six age groups. Multivariate logistic regression was used to evaluate associations between HHV8 and demographic data. RESULTS: An overall seropositivity rate of 17.6% was observed. The highest rate was observed in Sardinia (25.0%) and the lowest was found in Albania (13.9%). The prevalence rate increased linearly with age, from 9.7% in patients belonging to the 0-14 years age group to 26.3% for patients more than 59 years old. Seropositivity for HHV8 was significantly associated with membership of the 59 years-plus age group. Rates of seropositivity were significantly higher in patients from central southern Italy (OR = 1.7) and Sardinia (OR = 1.8) than in patients from Albania. CONCLUSIONS: The data suggest that HHV8 is widespread in the Mediterranean area, including regions like Albania that have not been previously investigated. The statistically significant association between HHV8 seropositivitity and increasing age suggests that non-sexual transmission routes may be involved in the spread of the virus.
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Anticuerpos Antivirales/sangre , Infecciones por Herpesviridae/epidemiología , Herpesvirus Humano 8/aislamiento & purificación , Adolescente , Adulto , Factores de Edad , Anciano , Células Cultivadas , Femenino , Infecciones por Herpesviridae/virología , Herpesvirus Humano 8/inmunología , Humanos , Recién Nacido , Masculino , Región Mediterránea/epidemiología , Persona de Mediana Edad , Oportunidad Relativa , Prevalencia , Estudios SeroepidemiológicosRESUMEN
Bacteria of the genus Vibrio include harmless aquatic strains as well as strains capable of causing epidemics of cholera and human intestinal diseases. Some of these species may show resistance to different antibiotics including cefotaxime, tetracycline and chloramphenicol. The susceptibility to different antibiotics was tested using 40 Vibrio alginolyticus, eight V. parahaemolyticus and six V. vulnificus strains isolated in the coastal waters of Northern Sardinia (Italy). The frequency of resistance to beta-lactams was unexpectedly high. More than 80% of Vibrio isolates were resistant to ampicillin and 2.5% of V. alginolyticus were resistant to ceftazidime and cefotetan. Forty percent of V. alginolyticus and three V. vulnificus isolates gave a positive nitrocefin test. PCR was also performed using selected primers chosen for having common sequences of bla(TEM) and bla(SHV) genes.
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Antibacterianos/farmacología , Vibrio/efectos de los fármacos , Microbiología del Agua , beta-Lactamasas/metabolismo , Cefalosporinas , ADN Bacteriano/análisis , Farmacorresistencia Microbiana , Indicadores y Reactivos , Pruebas de Sensibilidad Microbiana , Plásmidos , Reacción en Cadena de la Polimerasa , Vibrio/enzimología , Vibrio/aislamiento & purificación , beta-Lactamasas/genéticaRESUMEN
Sixty two patients diagnosed as having adult chlamydial ophthalmia were treated with oral doxycycline and roxithromycin in association and tetracycline eye wash for 2 weeks. Chlamydial ophthalmia was diagnosed by laboratory detection of the micro-organism in ocular specimens using direct immunofluorescent monoclonal antibody staining for Chlamydia trachomatis, chlamydial culture in cycloheximide treated McCoy cells, and Giemsa staining. An immunoenzymatic method for detection of specific IgG and IgA in patients' serum was used as an additional test to confirm the diagnosis. All patients were reexamined 3 weeks after completing their course of antibiotics and in the case of persistent infection a further course of treatment was given. With this treatment regimen 48 out of 62 patients (77.4%) were cured after three courses. Because of the risks of an inadequate response to therapy, we recommend a proper post-treatment follow up in all patients with chlamydial eye infections.
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Conjuntivitis de Inclusión/tratamiento farmacológico , Quimioterapia Combinada/uso terapéutico , Queratoconjuntivitis/tratamiento farmacológico , Administración Oral , Adolescente , Adulto , Anciano , Doxiciclina/uso terapéutico , Femenino , Técnica del Anticuerpo Fluorescente , Estudios de Seguimiento , Humanos , Técnicas para Inmunoenzimas , Masculino , Persona de Mediana Edad , Soluciones Oftálmicas , Roxitromicina/uso terapéutico , Tetraciclina/administración & dosificación , Resultado del TratamientoRESUMEN
AIMS: To identify and determine antibiotic susceptibility of coagulase negative staphylococci (CoNS) isolated from patients with chronic blepharitis, purulent conjunctivitis, and suppurative keratitis. METHODS: A retrospective review of all culture positive cases of chronic blepharitis, purulent conjunctivitis, and suppurative keratitis between July 1995 and December 1996 was performed. Cases in which CoNS were the sole isolates were analysed. Species identification was performed by using a commercially available standardised biochemical test system. Antibiotic susceptibility to penicillin, gentamicin, tetracycline, erythromycin, ciprofloxacin, and teicoplanin was determined by agar disc diffusion (Kirby-Bauer method). Teicoplanin resistance was confirmed by agar dilution. RESULTS: 42 Staphylococcus epidermidis, four S warneri, three S capitis, two S hominis, one each of S xylosus, S simulans, S equorum, and S lugdunensis were identified. 37 CoNS were penicillin resistant, 12 gentamicin resistant, 28 tetracycline resistant, 18 erythromycin resistant, four ciprofloxacin resistant, and one teicoplanin resistant (MIC, 32 microg/ml). In total, 16 strains were resistant to three or more antibiotics. CONCLUSION: Species of CoNS apart from S epidermidis may be isolated from patients with corneal and external infection. Antibiotic susceptibility of CoNS is unpredictable and multiresistant strains are common. As a result, antibiotic susceptibility testing should be performed in all cases of clinically significant ocular infections caused by CoNS.
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Antibacterianos/uso terapéutico , Infecciones Bacterianas del Ojo/tratamiento farmacológico , Infecciones Estafilocócicas/tratamiento farmacológico , Blefaritis/tratamiento farmacológico , Blefaritis/microbiología , Conjuntivitis Bacteriana/tratamiento farmacológico , Farmacorresistencia Microbiana , Infecciones Bacterianas del Ojo/microbiología , Gentamicinas/uso terapéutico , Humanos , Queratitis/tratamiento farmacológico , Queratitis/microbiología , Estudios Retrospectivos , Resistencia a la TetraciclinaRESUMEN
The antimicrobial activities of some copper(II) binary complexes with unsubstituted and different substituted phenanthroline ligands were investigated. A considerable increase in the biocidal activity of the ligands on being coordinated with the copper(II) ions was observed in terms of their minimum inhibitory concentration (MIC) values. EPR measurements were performed at room and low temperature with the aim of gaining an insight into the structure/activity relationship of these complexes. Subtle differences in the chemical arrangement result in appreciable differences in the antimicrobial activity. Copper(II) complexes with 2,9-dimethyl derivative phenanthrolines were observed to be more active against Staphylococcus aureus and Escherichia coli.
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Antiinfecciosos/química , Cobre/química , Espectroscopía de Resonancia por Spin del Electrón , Fenantrolinas/química , Simulación por Computador , Pruebas de Sensibilidad Microbiana , Estructura MolecularRESUMEN
The extent of the response of plant growth to atmospheric CO2 enrichment depends on the availability of resources other than CO2. An important growth-limiting resource under field conditions is nitrogen (N). N may, therefore, influence the CO2 response of plants. The effect of elevated CO2 (60 Pa) partial pressure (pCO2) on the N nutrition of field-grown Lolium perenne swards, cultivated alone or in association with Trifolium repens, was investigated using free air carbon dioxide enrichment (FACE) technology over 3 years. The established grassland ecosystems were treated with two N fertilization levels and were defoliated at two frequencies. Under elevated pCO2, the above-ground plant material of the L. perenne monoculture showed a consistent and significant decline in N concentration which, in general, led to a lower total annual N yield. Despite the decline in the critical N concentration (minimum N concentration required for non-N-limited biomass production) under elevated pCO2, the index of N nutrition (ratio of actual N concentration and critical N concentration) was lower under elevated pCO2 than under ambient pCO2 in frequently defoliated L. perenne monocultures. Thus, we suggest that reduced N yield under elevated pCO2 was evoked indirectly by a reduction of plant-available N. For L. perenne grown in association with T. repens and exposed to elevated pCO2, there was an increase in the contribution of symbiotically fixed N to the total N yield of the grass. This can be explained by an increased apparent transfer of N from the associated N2-fixing legume species to the non-fixing grass. The total annual N yield of the mixed grass/legume swards increased under elevated pCO2. All the additional N yielded was due to symbiotically fixed N. Through the presence of an N2-fixing plant species more symbiotically fixed N was introduced into the system and consequently helped to overcome N limitation under elevated pCO2.
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Enterococci are part of the dominant microbiota of several dairy products. They are also present in the gut of humans and animals. Their presence in traditional raw milk cheeses is probably due to faecal contamination of milk during milking. Due to their importance as a cause of nosocomial infections, enterococci are acquiring increased significance. Such infections are becoming more and more difficult to treat as resistance to antibiotics increases. The aim of this investigation was to compare the potential virulence of Enterococcus faecium isolated from different ecological habitats and to establish if strains isolated from dairy products should really be considered as potential pathogens. In the present work, the antibiotic resistance pattern of 40 E. faecium strains isolated from dairy products, 26 E. faecium isolated from ewes' faeces and 28 clinical isolates of the same species was studied, and checks were made to see if known virulence determinants were present. Resistance to 12 different antibiotics commonly used in the treatment of human infections was tested using the broth microdilution method as described by the NCCLS. In addition, polymerase chain reaction (PCR) tests were carried out to see if genes for vancomycin resistance were present. The presence of the aggregation substance (AS) gene, the surface protein gene esp, the accessory colonisation factor ace, the Enterococcus faecalis endocarditis antigen efaA and the gelatinase gelE gene, which are involved in the virulence of enterococci, were also tested by PCR. The results of this study clearly indicate that E. faecium strains isolated from both cheese and sheep faeces are less pathogenic than those isolated from clinical samples. A similar pattern of resistance to antibiotics was observed in both dairy and animal strains. It was also found that there was difference in the kind of virulence determinants present in dairy and clinical isolates, while no virulence traits were found in sheep faeces strains. The results of this study suggest that E. faecium from traditional Sardinian raw milk cheeses should not be considered to be the main source of untreatable nosocomial enterococcal infections in humans in the island of Sardinia.