RESUMEN
PURPOSE: To evaluate the benefit of targeted antibiotic prophylaxis (TAP) based on rectal swab culture in comparison with standard empiric antimicrobial prophylaxis in patients undergoing transrectal ultrasound-guided needle biopsy of the prostate (TRUS-BP), as well as to assess rate of fecal carriage of Fluoroquinolone-resistant Enterobacterales FQRE. PATIENTS AND METHODS: We prospectively analyzed data that randomized 157 patients within two groups: (G1) TAP according to rectal swab performed 10 days before PB; (G2): empirical antibiotic prophylaxis with ciprofloxacin. Prevalence of FQRE digestive carriage and risk factors were investigated. Incidence of infectious complications after (TRUS-BP) in each group was compared. RESULTS: G2 included 80 patients versus 77 in G1. There was no difference between the two groups regarding age, diabetes, prostate volume, PSA, number of biopsy cores, and risk factors for FQRE. In G2, the prevalence of FQRE digestive carriage was 56.3% all related to E. coli species. In the case of digestive carriage of FQRE, TAP according to the rectal swab culture with third-generation cephalosporins was performed in 73.3%. Patients with FQRE had history of FQ use within the last 6 months in 17.8% (p = 0.03). Rate of febrile urinary tract infection after PB was 13% in G1 and 3.8% in G2 (p = 0.02). CONCLUSIONS: Incidence of FQ resistance in the intestinal flora of our local population was prevalent. Risk factor for resistance was the use of FQ within the last 6 months. TAP adapted to rectal swab, mainly with third-generation cephalosporins, significantly reduced the rate of infectious complications after (TRUS-BP).
Asunto(s)
Profilaxis Antibiótica , Próstata , Recto , Humanos , Masculino , Estudios Prospectivos , Recto/microbiología , Próstata/patología , Anciano , Persona de Mediana Edad , Antibacterianos/uso terapéutico , Ciprofloxacina/uso terapéutico , Ciprofloxacina/administración & dosificación , Infecciones Urinarias/prevención & control , Infecciones Urinarias/microbiología , Infecciones Urinarias/epidemiología , Biopsia Guiada por Imagen/efectos adversos , Biopsia Guiada por Imagen/métodosAsunto(s)
Infecciones por Corynebacterium/microbiología , Corynebacterium/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Técnicas Bacteriológicas , Corynebacterium/genética , Infecciones por Corynebacterium/diagnóstico , ADN Bacteriano/química , ARN Polimerasas Dirigidas por ADN/química , ARN Polimerasas Dirigidas por ADN/genética , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , HumanosRESUMEN
We evaluated the Bruker Biotyper matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) for the identification of 97 Corynebacterium clinical in comparison to identification strains by Api Coryne and MALDI-TOF-MS using 16S rRNA gene and hypervariable region of rpoB genes sequencing as a reference method. C. striatum was the predominant species isolated followed by C. amycolatum. There was an agreement between Api Coryne strips and MALDI-TOF-MS identification in 88.65% of cases. MALDI-TOF-MS was unable to differentiate C. aurimucosum from C. minutissimum and C. minutissimum from C. singulare but reliably identify 92 of 97 (94.84%) strains. Two strains remained incompletely identified to the species level by MALDI-TOF-MS and molecular approaches. They belonged to Cellulomonas and Pseudoclavibacter genus. In conclusion, MALDI-TOF-MS is a rapid and reliable method for the identification of Corynebacterium species. However, some limits have been noted and have to be resolved by the application of molecular methods.
Asunto(s)
Técnicas de Tipificación Bacteriana/métodos , Corynebacterium/clasificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Proteínas Bacterianas/genética , Cellulomonas/clasificación , Cellulomonas/genética , Cellulomonas/aislamiento & purificación , Corynebacterium/genética , Corynebacterium/aislamiento & purificación , Infecciones por Corynebacterium/microbiología , ADN Bacteriano/genética , ADN Ribosómico/genética , ARN Polimerasas Dirigidas por ADN/genética , Humanos , Micrococcaceae/clasificación , Micrococcaceae/genética , Micrococcaceae/aislamiento & purificación , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Tiras Reactivas , RibotipificaciónRESUMEN
This study is the first one that describes the situation of Legionnaires' disease (LD) in Tunisia, with its clinical and epidemiological characteristics and investigates the risk factors associated with Legionella infections in our country. We conducted a retrospective multicentric study during 5 years (2008-2012) concerning all confirmed LD cases in Tunisia and we investigated risk factors for infection. The total of confirmed LD cases was 14. Incidence was 0.03. Mean age: 53.1, sex ratio (M/F): 2.6. Summer-autumnal peak was noted. Risk factors for infection were: the great humidity at home (n=4), living in community (n=3) and practice ablutions (before prayer) in public places (n=4). Community acquired legionellosis (n=9) and nosocomial (n=2). Pulmonary symptoms (n=11)+/-gastrointestinal (n=6) and/or neurological signs (n=4). Beta lactams therapy failed (n=11). CXR showed bilateral lesions (n=6). Abnormalities in laboratory values were noted: hyponatremia (n=9), high CPK levels (n=9). Diagnosis was confirmed by positive urinary Legionella antigens test (n=10) and by direct immunofluorescence (n=1). Treatment was based on bitherapy (n=10). Five patients died. The incidence of LD appears lower than other countries. Some risk factors, as ablutions, are different from that reported in Western countries and seem to be specific to our society. Given the seriousness of its consequences, it is strongly recommended to improve the national surveillance system up and register LD as notifiable disease.
Asunto(s)
Unidades de Cuidados Intensivos/estadística & datos numéricos , Enfermedad de los Legionarios/epidemiología , Anciano , Antibacterianos/uso terapéutico , Antígenos Bacterianos/orina , Baños , Líquido del Lavado Bronquioalveolar/microbiología , Infecciones Comunitarias Adquiridas/epidemiología , Comorbilidad , Infección Hospitalaria/epidemiología , Susceptibilidad a Enfermedades , Femenino , Hospitales Universitarios/estadística & datos numéricos , Vivienda , Humanos , Humedad , Incidencia , Legionella/aislamiento & purificación , Enfermedad de los Legionarios/diagnóstico , Enfermedad de los Legionarios/tratamiento farmacológico , Enfermedad de los Legionarios/transmisión , Tiempo de Internación/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Estaciones del Año , Fumar/epidemiología , Factores Socioeconómicos , Túnez , Microbiología del AguaRESUMEN
INTRODUCTION: We present recent data on the bacteriological profile and antibiotic susceptibility of uropathogenic bacteria isolated in children and newborns in our region over the past 2 years. MATERIALS AND METHODS: A retrospective study on the positive urine cultures from pediatric and neonatal populations during 2012-2013. Bacteria were identified using conventional methods. Susceptibility testing was performed and interpreted as recommended by the committee of the susceptibility of the French Society of Microbiology (CA-SFM). RESULTS: We collected 1879 non-redundant bacteria with more than 73% Escherichia coli. Children and infants (mean age, 32 months [range, 1 month to 14 years]) accounted for 84% of the bacteria collected and newborns (mean age, 12 days [range, 1 day to 1 month]) 16%. A female predominance was observed in the pediatric population (M:F sex ratio, 3.2), whereas for the neonatal population, the proportions were almost identical in both sexes (M:F sex ratio, 1.1). Most of the positive urine cultures (n=1234) were from the community. Hospitalized patients (n=636) were divided into pediatric (60%) and neonatal units (40%). Five bacterial genera dominated the bacteriological profile: E. coli, Klebsiella sp., Proteus sp., Enterobacter sp., and Enterococcus. The susceptibility of the main BUP antibiotics used for treatment of frequent UTI showed the effectiveness of furadoine, imipenem, fosfomycin, and colistin. Amoxicillin kept constant activity against Enterococcus and Streptococcus agalactiae. The rates of resistance of Enterobacteriaceae to beta-lactam antibiotics were high, especially in the neonatal population. The production of extended-spectrum beta-lactamase (ESBL) was noted in 12.8% of pediatric Enterobacteria vs. 22.6% of the neonatal strains. For community Enterobacteriaceae, the activity of beta-lactam antibiotics was limited with 11.2% resistance to third-generation cephalosporins (C3G), including 8.6% ESBL production. CONCLUSION: The impact of widespread use of beta-lactam antibiotics in neonatal and pediatric environments is felt. Colistin, imipenem, and fosfomycin are the most frequently used antibiotics active against bacteria responsible for neonatal and pediatric UTI; however, they cannot be used as probabilistic treatment. Nitrofurans seem to be active antibiotics on UTI, but they present limits in their use in neonatal and pediatric populations. Their indication in case of pyelonephritis should be discussed.
Asunto(s)
Antibacterianos/uso terapéutico , Infecciones Bacterianas/tratamiento farmacológico , Infecciones Bacterianas/microbiología , Bacteriuria/tratamiento farmacológico , Bacteriuria/microbiología , Pruebas de Sensibilidad Microbiana , Infecciones Urinarias/tratamiento farmacológico , Infecciones Urinarias/microbiología , Adolescente , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Estudios Retrospectivos , TúnezRESUMEN
OBJECTIVES: Extended-spectrum ß-lactamases are widespread in hospital settings worldwide. The prevalence of ESBL producing Klebsiella pneumoniae (ESBL-KP) strains isolated from patients has recently increased in Tunisia. We conducted this study to determine the prevalence and the genetic characterization of ESBL-KP in a Tunisian Hospital. PATIENTS AND METHODS: We performed antibiotic susceptibility testing, multiplex PCR, and DNA sequencing analysis on 118 non repetitive K. pneumonia strains isolated during three years, to determine the prevalence and genotypes of ESBL among K. pneumoniae clinical isolates. RESULTS: Most ESBL-producing K. pneumonia strains were isolated from hospitalized patients, especially in neonatal and pediatric wards. The resistance to other antibiotics was high. Most of the pathogens were isolated from the urinary tract (86.44%). Carbapenems were the most effective antimicrobial agents followed by amikacin and fosfomycin. The rate of blaSHV, blaTEM, and blaCTX-M genes among the isolates was 89, 56.78, and 81.35%, respectively. Sequencing revealed the amplicons encoding TEM-1, TEM-53, TEM-158, SHV-1, SHV-11, SHV-28, CTX-M-15, CTX-M-15-like. The blaCTX-M-15 was the dominant gene among Tunisian isolates, but this was the first report of blaTEM-53 and blaTEM-158 genes in the country. CONCLUSIONS: Our results confirm the predominance of CTX-M-15 in Tunisia. To our knowledge, this is the first report of TEM-158 and TEM-53 in Tunisia.
Asunto(s)
Proteínas Bacterianas/aislamiento & purificación , Infección Hospitalaria/microbiología , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/enzimología , Resistencia betalactámica/genética , beta-Lactamasas/aislamiento & purificación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Proteínas Bacterianas/clasificación , Proteínas Bacterianas/genética , Niño , Preescolar , Infección Hospitalaria/epidemiología , ADN Bacteriano/genética , ADN Bacteriano/aislamiento & purificación , Femenino , Genes Bacterianos , Genotipo , Departamentos de Hospitales , Hospitales Universitarios , Humanos , Lactante , Recién Nacido , Infecciones por Klebsiella/epidemiología , Klebsiella pneumoniae/efectos de los fármacos , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa Multiplex , Especificidad de la Especie , Túnez/epidemiología , Adulto Joven , beta-Lactamasas/clasificación , beta-Lactamasas/genéticaRESUMEN
Lactococcus lactis cremoris is rarely involved in human pathology. A thirty two-year old pregnant woman with premature rupture of membrane history presented with chorioamnionitis due to L. lactis cremoris. She underwent an emergency caesarian section and was treated with antibiotics including the association of amoxicillin and clavulanic acid. She was completely recovered. This is the first case to our knowledge of chorioamnionitis due to this organism.
RESUMEN
OBJECTIVE: We determined the macrolide resistance phenotypes and genotypes in Streptococcus pneumoniae isolates in Sousse and assessed the serotype distribution. METHODS: We included S. pneumoniae strains isolated at our laboratory (2010-2013). The antimicrobial susceptibility was tested according to CA-SFM specifications. Serotyping was performed by agglutination of latex particles, to identify a subset of serotypes included in pneumococcal conjugate vaccines. The presence of macrolide resistance genes (ermB, mefA, mel) was detected by PCR. RESULTS: A total of 52.8% of 140 S. pneumoniae isolates were macrolide-resistant: MLSB (89.2%) and M (10.8%). The MLSB phenotypes were genotypically confirmed by ermB gene presence. 62% had decreased susceptibility to penicillin. The serotypes were: 14, 1, 23F, and 19A. Serotype coverage by PCV7, PCV10 and PCV13 was 44.2%, 73.6%, and 75.6% respectively. CONCLUSION: 50% of S. pneumoniae isolates were macrolide resistant. The MLSB phenotype encoded by the ermB gene was the most frequent. Serotype coverage seems inadequate.
Asunto(s)
Macrólidos/farmacología , Streptococcus pneumoniae/efectos de los fármacos , Streptococcus pneumoniae/genética , Farmacorresistencia Bacteriana , Genotipo , Humanos , Fenotipo , Serogrupo , Streptococcus pneumoniae/aislamiento & purificación , TúnezAsunto(s)
Farmacorresistencia Microbiana , Gonorrea/microbiología , Neisseria gonorrhoeae/efectos de los fármacos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , ADN Bacteriano/genética , Farmacorresistencia Bacteriana Múltiple , Electroforesis en Gel de Campo Pulsado , Variación Genética , Genotipo , Gonorrea/tratamiento farmacológico , Gonorrea/epidemiología , Humanos , Pruebas de Sensibilidad Microbiana , Neisseria gonorrhoeae/genética , Neisseria gonorrhoeae/aislamiento & purificación , Viaje , Túnez/epidemiologíaRESUMEN
OBJECTIVE: Epidemiology of human herpesvirus 8 (HHV8) is still unknown in Tunisia. We aimed to assess the prevalence of HHV8 infection in adults and children from Central-East Tunisia and in patients with high risk of parenteral or sexual infection. METHODS: We enrolled 553 subjects: 116 blood donors, 100 pregnant women, 100 children, 50 subjects with sexually transmitted infections with positive HIV serology and 50 other without HIV infection, 107 multitransfused patients and 30 kidney transplant patients. Antibodies against HHV8 were tested using a sensitive indirect immunofluorescence assay. RESULTS: The seroprevalence of HHV8 was found to be 13.8% in blood donors, 13% in pregnant women and 12% in children. In healthy adult population, no association was found between HHV8 seropositivity and sex, sociodemographic characteristics, parenteral risk factors or serological markers of hepatitis B. Rates of HHV8 infection were significantly higher in patients having high-risk sexual behavior with or without HIV infection (P<10(-4)), in polytransfused patients (P<10(-4)) and in patients with kidney transplantation (P=0.001). CONCLUSION: Our findings suggest that HHV8 infection is widespread in Central-East Tunisia such as in the Mediterranean area. HHV8 infection appears to be acquired early in life, probably through saliva. HHV8 transmission by blood transfusion, subject of controversy in literature, is well established in our study. Early screening of this infection should be considered in populations with high risk of Kaposi's sarcoma in our areas.
Asunto(s)
Infecciones por Herpesviridae/epidemiología , Infecciones por Herpesviridae/etiología , Herpesvirus Humano 8 , Adolescente , Adulto , Anticuerpos Antivirales/sangre , Niño , Preescolar , Femenino , Infecciones por Herpesviridae/transmisión , Herpesvirus Humano 8/inmunología , Herpesvirus Humano 8/aislamiento & purificación , Humanos , Lactante , Masculino , Persona de Mediana Edad , Embarazo , Complicaciones Infecciosas del Embarazo/epidemiología , Complicaciones Infecciosas del Embarazo/etiología , Factores de Riesgo , Estudios Seroepidemiológicos , Conducta Sexual/fisiología , Enfermedades de Transmisión Sexual/sangre , Enfermedades de Transmisión Sexual/epidemiología , Enfermedades de Transmisión Sexual/etiología , Enfermedades de Transmisión Sexual/transmisión , Túnez/epidemiología , Adulto JovenRESUMEN
The aim of the study is to evaluate seroprevalence of rubella virus (RV), cytomegalovirus (CMV), varicella zoster virus (VZV), and parvovirus B19 (PB19) in 404 Tunisian pregnant women, and to determine reliability of maternal past history of eruption. Sociodemographic characteristics, risk factors, and past history of eruption were collected through a questionnaire. Serologic tests were performed using enzyme immunoassays. Risk factors were analyzed using univariate and multivariate logistic regression models. Seroprevalences were 79.7% for rubella, 96.3% for CMV, 80.9% for VZV, and 76.2% for PB19. In multivariate analysis, the number of persons per room (> 2) in the house during childhood was associated with CMV infection (P = 0.004), irregular professional husband's activity was correlated with VZV infection (P = 0.04), and an age of more than 30 years was associated with PB19 infection (P = 0.02). History of rubella, varicella, and PB19 infection was unknown for, respectively, 55.8%, 20%, and 100% of women. False history of rubella and varicella were found for 7.4% and 15% of women, respectively. The positive and negative predictive values (PPV and NPV) of rubella history were, respectively, 92.6% and 17.2%, and were, respectively, 84.9% and 20.9% for varicella history. Susceptibility to RV, VZV, and PB19 infection remains high in pregnancy in our population. Preventive strategies against congenital rubella must be reinforced. Vaccination against VZV should be considered in seronegative women. Systemic CMV screening is not warranted in our country where high immunity is acquired probably in childhood. Since maternal history of eruption is not reliable, we recommend serologic testing to determine immune status of women.
Asunto(s)
Anticuerpos Antivirales/sangre , Infecciones por Citomegalovirus/epidemiología , Citomegalovirus/inmunología , Herpes Zóster/epidemiología , Herpesvirus Humano 3/inmunología , Infecciones por Parvoviridae/epidemiología , Parvovirus B19 Humano/inmunología , Complicaciones Infecciosas del Embarazo/epidemiología , Virus de la Rubéola/inmunología , Rubéola (Sarampión Alemán)/epidemiología , Adulto , Femenino , Maternidades/estadística & datos numéricos , Hospitales Universitarios/estadística & datos numéricos , Humanos , Transmisión Vertical de Enfermedad Infecciosa/prevención & control , Valor Predictivo de las Pruebas , Embarazo , Complicaciones Infecciosas del Embarazo/virología , Estudios Prospectivos , Factores de Riesgo , Estudios Seroepidemiológicos , Factores Socioeconómicos , Encuestas y Cuestionarios , Adulto JovenRESUMEN
Urinary tract infection (UTI) in children is a grave pathology, which requires a fast and effective care. Bacteriological and epidemiological data play a determining role in patient's care. We report a retrospective study, which spreads out from January 1st till August 31st, 2009, having concerned hospitalized children for urinary infection in pediatrics service of Farhat Hached teaching hospital in Sousse. Our series contained 51 children with a sex ratio of 0.76, an average age of 32 months. The majority of cases was pyelonephritis (94.1%). A pathology is associated with the urinary infection in 41.2%. Three cases of vesico-ureteral reflux were noted. The diagnosis of urinary infection was confirmed by cytobacteriological exam of urine (CBEU). Enterobacteriacea were isolated in 96.1%. Escherichia coli remains the most often isolated (80.4%), followed by Klebsiella pneumoniae (9.8%) then by Proteus mirabilis (5.9%). E. coli was resistant to amoxicillin in 78% of cases, to the association amoxicillin-clavulanic acid in 64,8%, to cephalosporins of 3(rd) generation (C3G) in 5% and to cotrimoxazole in 51%. No K. pneumoniae or P. mirabilis strain was resistant to C3G. UTI in children is always an indication for CBEU realization at first intention. The results of this exam are very important considering the diversity of the responsible bacteria and the growing frequency of acquired antibiotic resistance.
Asunto(s)
Infecciones Urinarias/epidemiología , Infecciones Urinarias/microbiología , Bacterias/aislamiento & purificación , Preescolar , Femenino , Humanos , Masculino , Estudios RetrospectivosRESUMEN
OBJECTIVE: The aim of this study was to determine the antimicrobial activity of amoxicillin-clavulanic acid against Escherichia coli urinary strains, especially those resistant to amoxicillin, and to analyze the results according to the susceptibility testing methods. METHOD: This prospective study was made from April to May 2008, on 301 E. coli strains isolated from urine samples. The susceptibility to antibiotics was studied by agar disk diffusion according to French Society of Microbiology Antibiogram Committee recommendations. MIC were determined with the E-test. RESULTS: According to the antibiogram, 59.8% of strains were resistant to amoxicillin, 33.2% to amoxicillin-clavulanic acid, 1.7% to cefotaxim, 8.3% to nalidixic acid, 6.6% to ofloxacin, 4.7% to ciprofloxacin, 4.7% to gentamicin and 38.1% to cotrimoxazole. After determining the MIC of E. coli strains resistant to amoxicillin and susceptible to amoxicillin-clavulanic acid, 37.5% (n=30) remained susceptible, 61.25% (n=55) were of intermediate susceptibility and only one strain (1.25%) was resistant. Among E. coli strains resistant to amoxicillin and intermediately susceptible to amoxicillin-clavulanic acid, 83.3% (n=55) remained intermediately susceptible, 13.7% (n=9) became susceptible and two strains (3%) were resistant. CONCLUSION: The susceptibility testing methods, especially for amoxicillin-clavulanic acid, must be standardized to avoid the discrepancies noted between standard antibiograms and an accurate determination of MIC.
Asunto(s)
Combinación Amoxicilina-Clavulanato de Potasio/farmacología , Antibacterianos/farmacología , Escherichia coli/efectos de los fármacos , Sistema Urinario/microbiología , Farmacorresistencia Bacteriana , Escherichia coli/aislamiento & purificación , Humanos , Pruebas de Sensibilidad Microbiana , Estudios ProspectivosRESUMEN
The direct impact of fenpropimorph on the sterol biosynthesis pathway of Glomus intraradices when extraradical mycelia alone are in contact with the fungicide was investigated using monoxenic cultures. Bi-compartmental Petri plates allowed culture of mycorrhizal chicory roots in a compartment without fenpropimorph and exposure of extraradical hyphae to the presence of increasing concentrations of fenpropimorph (0, 0.02, 0.2, 2, 20 mg l(-1)). In the fungal compartment, sporulation, hyphal growth, and fungal biomass were already reduced at the lowest fungicide concentration. A decrease in total sterols, in addition to an increase in the amount of squalene and no accumulation of abnormal sterols, suggests that the sterol pathway is severely slowed down or that squalene epoxidase was inhibited by fenpropimorph in G. intraradices. In the root compartment, neither extraradical and intraradical development of the arbuscular mycorrhizal (AM) fungus nor root growth was affected when they were not in direct contact with the fungicide; only hyphal length was significantly affected at 2 mg l(-1) of fenpropimorph. Our results clearly demonstrate a direct impact of fenpropimorph on the AM fungus by a perturbation of its sterol metabolism.
Asunto(s)
Antifúngicos/farmacología , Vías Biosintéticas/efectos de los fármacos , Glomeromycota/efectos de los fármacos , Glomeromycota/crecimiento & desarrollo , Morfolinas/farmacología , Esteroles/biosíntesis , Biomasa , Cichorium intybus/microbiología , Escualeno/metabolismoRESUMEN
Streptococcus agalactiae or Group B Streptococcus (GBS) is one of the main bacterial causes of serious infections in newborns. We have evaluated prospectively GBS vaginal colonization in pregnant women and we have tried to determine the risk factors of the colonization by GBS and the particularities of the different isolated strains. We have screened 300 pregnant women with vaginal and anal sample in a same swab. Thirty nine (13%) pregnant women are colonized by SGB, 0% in the first trimester, 10.2% in the second trimester and 17% in the third trimester. Different factors are associated significantly with GBS colonization: past history of infection in newborns, genital infection during pregnancy and parity The highest rates of resistance are found in tetracycline (97.4%), erythromycin (51.3%) and lincomycin (46.2%). All the strains were susceptible to amoxicilin and pristinamycin.
Asunto(s)
Streptococcus agalactiae/efectos de los fármacos , Streptococcus agalactiae/crecimiento & desarrollo , Vagina/microbiología , Adolescente , Adulto , Eritromicina , Femenino , Edad Gestacional , Humanos , Recién Nacido , Lincomicina , Pruebas de Sensibilidad Microbiana , Paridad , Embarazo , Factores de Riesgo , Infecciones Estreptocócicas , Streptococcus agalactiae/aislamiento & purificación , Resistencia a la Tetraciclina , TúnezRESUMEN
The influence of anthracene, a low molecular weight polycyclic aromatic hydrocarbon (PAH), on chicory root colonization by Glomus intraradices and the effect of the root colonization on PAH degradation were investigated in vitro. The fungus presented a reduced development of extraradical mycelium and a decrease in sporulation, root colonization, and spore germination when exposed to anthracene. Mycorrhization improved the growth of the roots in the medium supplemented containing 140 mg l(-1) anthracene, suggesting a positive contribution of G. intraradices to the PAH tolerance of roots. Anthracene disappearance from the culture medium was quantified; results suggested that nonmycorrhizal chicory roots growing in vitro were able to contribute to anthracene dissipation, and in addition, that mycorrhization significantly enhanced anthracene dissipation. These monoxenic experiments demonstrated a positive contribution of the symbiotic association to anthracene dissipation in the absence of other microorganisms. In addition to anthracene dissipation, intracellular accumulation of anthracene was detected in lipid bodies of plant cells and fungal hyphae, indicating intracellular storage capacity of the pollutant by the roots and the mycorrhizal fungus.
Asunto(s)
Antracenos/farmacología , Cichorium intybus/microbiología , Micorrizas/efectos de los fármacos , Micorrizas/metabolismo , Antracenos/metabolismo , Cichorium intybus/efectos de los fármacos , Cichorium intybus/metabolismo , Lacasa/metabolismo , Microscopía Fluorescente , Micorrizas/enzimología , Peroxidasa/metabolismo , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Raíces de Plantas/microbiología , Esporas Fúngicas/crecimiento & desarrollo , SimbiosisRESUMEN
⢠Characteristic sterols of transformed carrot (Daucus carota) and chicory (Cichorium intybus) roots colonized by different strains of arbuscular mycorrhizal (AM) fungi were identified. ⢠Sterols were extracted, analysed and identified by gas chromatography/mass spectrometry (GC-MS) from monoxenic cultures of mycorrhizal and nonmycorrhizal roots. After colonization by Glomus intraradices, Glomus proliferum and Glomus sp., carrot and chicory roots exhibited a significantly higher 24-methyl/methylene sterol content. A correlation was established between the content of the sum of 24-methyl cholesterol, 24-methylene cholesterol and 24-methyl desmosterol. ⢠This study clearly established that the increment of these characteristic sterols is an appropriate indicator of colonization by AM fungi of transformed roots. ⢠Metabolic origin and specificity of these sterols in mycorrhizal roots was researched. The 24-methyl/methylene sterol increase was observed only when the interaction between fungus and plant was completely established and the fungus was present inside the roots.
RESUMEN
Transgenic lines of indica rice were generated by Agrobacterium-mediated transformation with the choline oxidase ( codA) gene from Arthrobacter globiformis. Choline oxidase catalyses conversion of choline to glycine betaine. Glycine betaine is known to provide tolerance against a variety of stresses. Molecular analyses of seven independent transgenic lines as performed by Southern, Northern and Western hybridization revealed integration and expression of the transgene as well as inheritance in the progeny plants. A good correlation was observed between levels of mRNA and protein accumulation, and a significant amount of choline oxidase product, i.e. glycine betaine, accumulated in R0 as well as R1 plants. Mendelian as well as non-Mendelian segregation patterns were obtained in the progeny plants. Challenge studies performed with R1 plants by exposure to salt stress (0.15 M NaCl) for 1 week, followed by a recovery period, revealed that in some cases more than 50% of the transgenic plants could survive salt stress and set seed whereas wild-type plants failed to recover.
Asunto(s)
Cinamatos , Higromicina B/análogos & derivados , Nucleósido Desaminasas/genética , Oryza/genética , Presión Osmótica , Plantas Modificadas Genéticamente , Betaína/metabolismo , Citosina Desaminasa , Higromicina B/metabolismo , Nucleósido Desaminasas/metabolismo , Oryza/fisiologíaRESUMEN
The use of monoxenic cultures of the obligately biotrophic vesicular arbuscular fungus Glomus intraradices now permits investigation of the lipid metabolism of this organism. In bicompartmental culture plates, sporulating extraradical hyphae can be obtained, totally free of roots, and then provided with 14C-acetate as lipid precursor. Three experimental stages were studied: i) stage A, symbiotic stage corresponding to the fungus still attached to the host plant roots, ii) stage B, consisting of the fungus detached from the host roots, iii) stage C, germinating spores. In each case, the fungus proved to be able to synthesise its own lipids: 1,2- and 1,3-diacylglycerols, triacylglycerols, phospholipids, sterols and free fatty acids, de novo. Lipid metabolism varied with the experimental conditions. Phospholipid synthesis was intensive in germinating spores. Thus the obligately biotrophic status of this fungus cannot be explained by a deficiency in synthesis of these various lipid classes.
Asunto(s)
Acetatos/metabolismo , Hongos/fisiología , Metabolismo de los Lípidos , Radioisótopos de Carbono , Diglicéridos/metabolismo , Ácidos Grasos no Esterificados/metabolismo , Hongos/metabolismo , Fosfolípidos/metabolismo , Raíces de Plantas/microbiología , Técnica de Dilución de Radioisótopos , Rhizobium/genética , Esporas Fúngicas , Esteroles/metabolismo , Transformación Genética , Triglicéridos/metabolismoRESUMEN
When photosystem (PS) II-enriched membranes are exposed to strong light, cross-linking of the intrinsic D1 protein with the surrounding polypeptides and degradation of the D1 protein take place. The cross-linking of the D1 protein with the alpha-subunit of cytochrome b(559) is suggested to be an early event of photoinduced damage to the D1 protein (Barbato et al., FEBS Lett. 309 (1992) 165-169). The relationship between the cross-linking and the degradation of the D1 protein, however, is not yet clear. In the present study, we show that the addition of stromal extract from chloroplasts degrades the 41 kDa cross-linked product of D1/cytochrome b(559) alpha-subunit and enhances the degradation of the D1 protein. Incubation of the preilluminated PS II-enriched membranes with the stromal extract at 25 degrees C causes the degradation of the cross-linked product by more than 70%. The activity of the stromal extract showed a pH optimum at 8.0, and was enhanced by the addition of ATP or GTP. Consistent with the nucleotide effect, this stromal activity was eliminated by the preincubation of the stromal extract with apyrase, which hydrolyzes nucleotides. Also, the stromal activity was nearly fully inhibited by a serine-type protease inhibitor, 3,4-dichloroisocoumarin, which suggests participation of a serine-type protease(s).