RESUMO
Shiga toxin-producing Escherichia coli (STEC) are important food-borne pathogens associated with human diseases. In Argentina, O157:H7 is the dominant serotype in hemolytic uremic syndrome (HUS) cases. Previously, we have described the almost exclusive circulation of human E. coli O157 strains belonging to the hypervirulent clade 8 in Neuquén Province. The aim of the present study was to investigate, by a broad molecular characterization, if this particular distribution of E. coli O157 clades in Neuquén is similar to the situation in other regions of the country and if it may be originated in a similar profile in cattle, its main reservoir. Two-hundred and eighty O157 strains (54 bovine and 226 human) isolated between 2006 and 2008 in different regions of Argentina were studied. All strains harbored rfbO157, fliCH7, eae, and ehxA genes. The predominant genotype was stx2a/stx2c in human (76.1%) and bovine (55.5%) strains. All human isolates tested by Lineage-Specific Polymorphism Assay (LSPA-6), were lineage I/II; among bovine strains, 94.1% belonged to lineage I/II and 5.9% to lineage I. No LSPA-6 lineage II isolates were detected. Single nucleotide polymorphism (SNP) analysis has revealed the existence of nine clade phylogenetic groups. In our clinical strains collection, 87.6% belonged to the hypervirulent clade 8, and 12.4% were classified as clade 4/5. In bovine isolates, 59.3% strains were clade 8, 33.3% clade 4/5 and 7.4% clade 3. More than 80% of human strains showed the presence of 6 of the 7 virulence determinants described in the TW14359 O157 strain associated with the raw spinach outbreak in the U.S. in 2006. More than 80% of bovine strains showed the presence of 3 of these factors. The q933 allele, which has been related to high toxin production, was present in 98.2% of clinical strains and 75.9% of the bovine isolates. The molecular characterization of human STEC O157 strains allows us to conclude that the particular situation previously described for Neuquén Province, may actually be a characteristic of the whole country. These genetic features are quite similar to those observed in the bovine reservoir and may be derived from it. This data confirms that, unlike the rest of the world, in Argentina most of the STEC O157 strains present in cattle may cause human infections of varying severity and the marked virulence described for these strains may be related to the high incidence of HUS in our country.
Assuntos
Doenças dos Bovinos/microbiologia , Infecções por Escherichia coli/microbiologia , Escherichia coli O157/genética , Síndrome Hemolítico-Urêmica/microbiologia , Alelos , Animais , Argentina/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Reservatórios de Doenças , Eletroforese em Gel de Campo Pulsado , Infecções por Escherichia coli/epidemiologia , Escherichia coli O157/classificação , Escherichia coli O157/isolamento & purificação , Escherichia coli O157/patogenicidade , Genótipo , Síndrome Hemolítico-Urêmica/epidemiologia , Humanos , Fenótipo , Polimorfismo Genético , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Virulência/análiseRESUMO
The non-O157 Shiga toxin-producing Escherichia coli (STEC) contamination in carcasses and feces of 811 bovines in nine beef abattoirs from Argentina was analyzed during a period of 17 months. The feces of 181 (22.3%) bovines were positive for non-O157 STEC, while 73 (9.0%) of the carcasses showed non-O157 STEC contamination. Non-O157 STEC strains isolated from feces (227) and carcasses (80) were characterized. The main serotypes identified were O178:H19, O8:H19, O130:H11, and O113:H21, all of which have produced sporadic cases of hemolytic-uremic syndrome in Argentina and worldwide. Twenty-two (7.2%) strains carried a fully virulent stx/eae/ehxA genotype. Among them, strains of serotypes O103:[H2], O145:NM, and O111:NM represented 4.8% of the isolates. Xba I pulsed-field gel electrophoresis pattern analysis showed 234 different patterns, with 76 strains grouped in 30 clusters. Nine of the clusters grouped strains isolated from feces and from carcasses of the same or different bovines in a lot, while three clusters were comprised of strains distributed in more than one abattoir. Patterns AREXSX01.0157, AREXBX01.0015, and AREXPX01.0013 were identified as 100% compatible with the patterns of one strain isolated from a hemolytic-uremic syndrome case and two strains previously isolated from beef medallions, included in the Argentine PulseNet Database. In this survey, 4.8% (39 of 811) of the bovine carcasses appeared to be contaminated with nonO157 STEC strains potentially capable of producing sporadic human disease, and a lower proportion (0.25%) with strains able to produce outbreaks of severe disease.
Assuntos
Matadouros , Bovinos/microbiologia , Qualidade de Produtos para o Consumidor , Contaminação de Alimentos/análise , Escherichia coli Shiga Toxigênica/isolamento & purificação , Animais , Argentina/epidemiologia , DNA Bacteriano/análise , Surtos de Doenças/prevenção & controle , Fezes/microbiologia , Feminino , Contaminação de Alimentos/prevenção & controle , Genótipo , Síndrome Hemolítico-Urêmica/epidemiologia , Síndrome Hemolítico-Urêmica/prevenção & controle , Humanos , Masculino , Prevalência , Medição de Risco , Sorotipagem , Escherichia coli Shiga Toxigênica/classificação , Pele/microbiologiaRESUMO
In Argentina, Escherichia coli O157:H7/NM (STEC O157) is the prevalent serotype associated with hemolytic uremic syndrome (HUS), which is endemic in the country with more than 400 cases per year. In order to estimate the prevalence and characteristics of STEC O157 in beef cattle at slaughter, a survey of 1,622 fecal and carcass samples was conducted in nine beef exporting abattoirs from November 2006 to April 2008. A total of 54 samples were found positive for STEC O157, with an average prevalence of 4.1% in fecal content and 2.6% in carcasses. Calves and heifers presented higher percentages of prevalence in feces, 10.5 and 8.5%, respectively. All STEC O157 isolates harbored stx(2) (Shiga toxin 2), eae (intimin), ehxA (enterohemolysin), and fliC(H7) (H7 flagellin) genes, while stx(1) (Shiga toxin 1) was present in 16.7% of the strains. The prevalent (56%) stx genotype identified was stx(2) combined with variant stx(2c (vh-a)), the combination of which is also prevalent (>90%) in STEC O157 post-enteric HUS cases in Argentina. The clonal relatedness of STEC O157 strains was established by phage typing and pulsed-field gel electrophoresis (PFGE). The 54 STEC isolates were categorized into 12 different phage types and in 29 XbaI-PFGE patterns distributed in 27 different lots. STEC O157 strains isolated from 5 of 21 carcasses were identical by PFGE (100% similarity) to strains of the fecal content of the same or a contiguous bovine in the lot. Five phage type-PFGE-stx profiles of 10 strains isolated in this study matched with the profiles of the strains recovered from 18 of 122 HUS cases that occurred in the same period.
Assuntos
Matadouros , Bovinos/microbiologia , Escherichia coli O157 , Fezes/microbiologia , Toxinas Shiga/biossíntese , Animais , Argentina/epidemiologia , Tipagem de Bacteriófagos , Análise por Conglomerados , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , DNA Bacteriano/análise , Escherichia coli O157/classificação , Escherichia coli O157/genética , Escherichia coli O157/isolamento & purificação , Escherichia coli O157/metabolismo , Genótipo , Síndrome Hemolítico-Urêmica/epidemiologia , Síndrome Hemolítico-Urêmica/microbiologia , Humanos , Epidemiologia Molecular , Fenótipo , Prevalência , Toxinas Shiga/genéticaRESUMO
A total of 120 freshly harvested wheat samples from the 2004 season in nine locations from Northern Buenos Aires Province, Argentina, were analysed for trichothecene natural occurrence and associated mycoflora, and for determining the influence of commonly used fungicide field treatment and the cultivar type on trichothecene contamination. The trichothecenes T-2 tetraol, T-2 triol, HT-2 and T-2 toxin (HT-2, T-2), diacetoxyscirpenol (DAS), nivalenol (NIV), deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON) and 15-acetyldeoxynivalenol (15-ADON) were analysed by gas chromatography and electron capture detection. Detection limits ranged from 4 to 20 microg/kg. The isolation frequencies of species were calculated. Alternaria alternata, Fusarium graminearum, Fusarium poae and Fusarium semitectum were the predominant fungal species identified as endogenous mycoflora. The type of cultivar and the fungicide field treatment did not affect significantly the trichothecene contamination. The trichothecenes type A detected were HT-2 and T-2 triol toxins and the type B were DON, NIV and 3-ADON. Based on 120 samples the incidences were 21.7% for 3-ADON, 22.5% for HT-2, 27.5% for T-2 triol and 85% for DON. NIV was confirmed in one sample. Mean levels of trichothecene positive samples were between 7 and 2788 microg/kg.
Assuntos
Fungos/isolamento & purificação , Tricotecenos/análise , Triticum/microbiologia , Alternaria/isolamento & purificação , Alternaria/metabolismo , Argentina , Cromatografia Gasosa , Fungos/classificação , Fungos/metabolismo , Fusarium/isolamento & purificação , Fusarium/metabolismo , Especificidade da Espécie , Tricotecenos/químicaRESUMO
Naturally contaminated beef-brisket fat showed a psychrotroph count of 4 × 10(9) CFU/cm(2) after 14 days of aerobic refrigerated storage (5°C ± 1°C). Pseudomonas was the predominating genus. Other micro-organisms, such as Enterobacteriaceae and Brochothrix thermosphacta, grew up to 2·5 × 10(8) cfu/cm(2) and 1·6 × 10(8) cfu/cm(2), respectively. Concentrations of different substrates that could support microbial growth were measured. Glucose concentration dropped to approximately one-third of the initial level during the first week of storage. Lactic acid also declined. Free fatty acids increased significantly (P < 0·05) during refrigeration. However, other lipid-deterioration indices, such as the thiobarbituric acid number and the peroxide value, remained unchanged. Beef subcutaneous fat had a high initial microbial load and a capacity to support extensive bacterial growth. It may therefore constitute an important source of contamination for meat and manufactured meat products.
RESUMO
Using hepatocytes isolated by collagenase perfusion, we studied the accumulation of 3H-noradrenaline. Cells incubated during 15 min in the presence of 0.4 mumol/l 3H-noradrenaline (without inhibition of noradrenaline metabolism) accumulated 8.32 +/- 1.77 pmol/10(6) cells (n = 3). The accumulation of 3H-noradrenaline in isolated parenchymal liver cells was sensitive to 10 mumol/l cocaine (inhibition 36.6 +/- 7.9%, n = 3) and 1 mumol/l desipramine (inhibition 27.2 +/- 6.9, n = 3). Accumulation of 3H-noradrenaline was temperature and sodium dependent (inhibition 33.2 +/- 9.4%, n = 9, when Na+ was replaced by Tris+) and was influenced by the inhibition of the membrane Na(+)-K(+)-adenosine triphosphatase (Na(+)-K(+)-ATPase) by 150 mumol/l ouabain (34.7 +/- 6.9% inhibition, n = 3). Accumulation of 3H-noradrenaline in the hepatocytes was not affected by the presence of uptake2 inhibitors, normetanephrine (30 mumol/l) and corticosterone (30 mumol/l), but was reduced by 30 mumol/l isoprenaline (76.3 +/- 5.0% inhibition, n = 6). Thus, the system that takes up and accumulates noradrenaline in the isolated rat liver cells possesses some characteristics of both, uptake1 and uptake2 systems and appears to be different from other extraneuronal cocaine-sensitive systems, such as the one reported for pulmonary endothelial cells.
Assuntos
Fígado/metabolismo , Norepinefrina/metabolismo , Animais , Técnicas In Vitro , Isoproterenol/farmacologia , Fígado/citologia , Masculino , Normetanefrina/farmacologia , Ouabaína/farmacologia , Ratos , Ratos Endogâmicos , Sódio/fisiologia , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Temperatura , Fatores de TempoRESUMO
Diltiazem, a calcium-channel blocking agent, has been shown to be a potent coronary vasodilator used in the treatment of ischaemic heart disease. The present study was conducted to compare the bioavailability of regular 60 mg tablets administered every 6 h with sustained release capsules of 120 mg administered every 12 h. High-performance liquid chromatographic analysis was carried out for determination of diltiazem and one of its metabolites desacetyldiltiazem in six male patients. The relative bioavailability of this sustained-release pharmaceutical form did not show any significant difference with that of tablets.
Assuntos
Diltiazem/farmacocinética , Cápsulas , Cromatografia Líquida de Alta Pressão , Preparações de Ação Retardada , Diltiazem/administração & dosagem , Humanos , Masculino , Comprimidos , Equivalência TerapêuticaRESUMO
Eight male tuberculous patients, between 20 and 60 years of age, were given Isoniazid 5 mg/kg and Ketoconazole 200 mg, first one at a time and then associated. Plasma concentrations were measured 0, 2 and 5 hs after taking the drugs. Isoniazid was measured by spectrophotometry and Ketoconazole by the microbiologic method with Candida albicans as test microorganism. When both drugs were given simultaneously Ketoconazole plasma concentration decreased 75% at 2 hs (p less than 0.025) and 85% at 5 hs (p less than 0.05), whereas that of Isoniazid remained unchanged (Table 1). Mean half-life of Isoniazid was 3.9 +/- 1.4 hs in 7 slow acetylators and 1.1 hs in one fast acetylator when given one at a time and 4.4 +/- 1.5 hs when given simultaneously. A similar study was conducted on 11 tuberculous patients who were given Rifampicin 10 mg/kg and Ketoconazole 200 mg, one at a time and concurrently. Rifampicin was measured by high pressure liquid chromatography. When Rifampicin and Ketoconazole were given concurrently plasma concentration of both drugs was reduced: Ketoconazole decreased 85% at 2 hs (p less than 0.025) and 98% at 5 hs (p less than 0.025) whereas Rifampicin decreased 45% at 2 hs (p less than 0.005) and 40% at 5 hs (p less than 0.005) (Table 2). Mean half-life of Rifampicin was 3.5 +/- 0.8 and 4.2 +/- 1.1 hs, respectively, when it was given alone and concurrently. Studies on chemical interactions between Isoniazid and Ketoconazole and between Rifampicin and Ketoconazole yielded negative results.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Isoniazida/sangue , Cetoconazol/sangue , Rifampina/sangue , Tuberculose/metabolismo , Adulto , Ensaios Clínicos como Assunto , Interações Medicamentosas , Quimioterapia Combinada , Humanos , Isoniazida/administração & dosagem , Cetoconazol/administração & dosagem , Masculino , Pessoa de Meia-Idade , Rifampina/administração & dosagem , Tuberculose/tratamento farmacológicoRESUMO
Eight male tuberculous patients, between 20 and 60 years of age, were given Isoniazid 5 mg/kg and Ketoconazole 200 mg, first one at a time and then associated. Plasma concentrations were measured 0, 2 and 5 hs after taking the drugs. Isoniazid was measured by spectrophotometry and Ketoconazole by the microbiologic method with Candida albicans as test microorganism. When both drugs were given simultaneously Ketoconazole plasma concentration decreased 75
at 2 hs (p less than 0.025) and 85
at 5 hs (p less than 0.05), whereas that of Isoniazid remained unchanged (Table 1). Mean half-life of Isoniazid was 3.9 +/- 1.4 hs in 7 slow acetylators and 1.1 hs in one fast acetylator when given one at a time and 4.4 +/- 1.5 hs when given simultaneously. A similar study was conducted on 11 tuberculous patients who were given Rifampicin 10 mg/kg and Ketoconazole 200 mg, one at a time and concurrently. Rifampicin was measured by high pressure liquid chromatography. When Rifampicin and Ketoconazole were given concurrently plasma concentration of both drugs was reduced: Ketoconazole decreased 85
at 2 hs (p less than 0.025) and 98
at 5 hs (p less than 0.025) whereas Rifampicin decreased 45
at 2 hs (p less than 0.005) and 40
at 5 hs (p less than 0.005) (Table 2). Mean half-life of Rifampicin was 3.5 +/- 0.8 and 4.2 +/- 1.1 hs, respectively, when it was given alone and concurrently. Studies on chemical interactions between Isoniazid and Ketoconazole and between Rifampicin and Ketoconazole yielded negative results.(ABSTRACT TRUNCATED AT 250 WORDS)
RESUMO
The influence of inhibitors of metabolism and uptake of noradrenaline on the 3H-noradrenaline removal from the perfusion fluid by the isolated rat liver was studied. Livers were perfused with 3 nmol/l 3H-noradrenaline and 3H-noradrenaline and 3H-metabolites were determined in effluent, liver and bile. After the perfusion with 14,900 +/- 920 dpm.g-1.min-1 during 90 min, cumulative removal of tritium was 323,574 +/- 63,103 dpm/g. 3H-metabolites recovered from the liver after 90 min perfusion represented 71.1 +/- 9.0% of total metabolite formation. Only the OMDA-fraction appeared in the perfusate; its approach to steady state of efflux was slow. The inhibition either of MAO or COMT changed neither the total removal of tritium nor the 3H-metabolites recovered from the liver. Cocaine (10 mumol/l) reduced the accumulation of 3H-noradrenaline in the liver. The uptake2 inhibitor corticosterone (30 mumol/l) diminished total removal of tritium and the 3H-metabolites recovered from the liver without changing the accumulation of 3H-noradrenaline. The hypothesis of two different compartments, one responsible for the metabolism and the other for the accumulation of the amine is discussed.