RESUMEN
Purpose Cerebral venous sinus thrombosis (CVST) is an unusual and potentially life-threatening condition with variable and nonspecific clinical symptoms and high morbimortality rates. Standard therapy consists of systemic anticoagulation; although there is no clear evidence about the best choice for treatment, intravenous heparin is used as the first-line treatment modality. Intravenous sinus thrombolysis can be an effective and relatively safe treatment for acutely deteriorating patients who have not responded to conventional therapy. This case report presents the possibility of endovascular treatment in multiple steps with mechanical thrombolysis with balloon, local pharmacological thrombolysis and stenting, in a patient with a severe form of CVST. Case summary A 67-year-old woman presented severe headache, agitation and confusion with diagnosis of venous sinus dural thrombosis in both lateral sinus and torcula. After 24 h there was neurological worsening evolving with seizures and numbness even after starting heparin, without sinus recanalization; CT scan showed left temporal intracerebral hemorrhage. We decided to take an endovascular approach in multiple steps. The first step was mechanical static thrombolysis with balloon; the second step was dynamic mechanical thrombolysis with a balloon partially deflated and "pulled"; the third step was local thrombolysis with Actilyse™; finally, the fourth step was angioplasty and reconstruction of the sinuses using multiple carotid stents and complete angiographic recanalization of both sinuses and torcula. After 24 h of endovascular treatment there was full clinical recovery and no tomographic complications. Conclusion This result shows that mechanical clot disruption, intrasinus thrombolysis and reconstruction of wall sinuses with stenting can be an endovascular option in the severe form of CVST with intracerebral hemorrhage and rapid worsening of neurological symptoms. Although this type of treatment can re-channel the occluded sinuses, further comparative and randomized studies are needed to clarify its efficacy versus other therapeutic modalities.
Asunto(s)
Trombolisis Mecánica , Trombosis de los Senos Intracraneales/diagnóstico por imagen , Trombosis de los Senos Intracraneales/terapia , Stents , Terapia Trombolítica , Anciano , Angiografía de Substracción Digital , Angiografía Cerebral , Diagnóstico Diferencial , Femenino , Escala de Coma de Glasgow , Humanos , Tomografía Computarizada por Rayos XRESUMEN
INTRODUCTION: There has been a great improvement in transplantation medicine in Brazil in the last 2 decades. However, there remain several barriers regarding notification of brain and cardiac death as well as completion of the donation process. METHODS: This retrospective study was performed between January 2008 and December 2010. We reviewed all deaths in a University Hospital, observing the causes of non-notification to the State Transplantation Authority and non-donations. RESULTS: There were 41 notifications of brain death resulting in donation in only 19.5% of those cases. Cardiac death was diagnosed in 21 patients, resulting in 52.4% donations. The main cause for non-donation were family refusal (37.2%), infectious diseases (30.2%), and clinical contraindications (32.6%). Most of the missed possible donors occurred during the night (54.8%) and in the emergency room (80.9%). CONCLUSION: There is an urgent need for better education of the Brazilian population about organ donation and brain death definitions. Other identified problems include lack of uniformity in brain death determinations among hospitals, rigid contraindications to donation in the State of Parana, physician unawareness or disbelief about brain death diagnostic criteria, and lack of structure of our Hospital.
Asunto(s)
Muerte Encefálica/diagnóstico , Selección de Donante , Familia/psicología , Consentimiento por Terceros , Obtención de Tejidos y Órganos , Altruismo , Actitud del Personal de Salud , Concienciación , Brasil , Causas de Muerte , Enfermedades Transmisibles/mortalidad , Servicio de Urgencia en Hospital , Donaciones , Conocimientos, Actitudes y Práctica en Salud , Hospitales Universitarios , Humanos , Motivación , Rol del Médico , Estudios Retrospectivos , Factores de TiempoRESUMEN
Systemic and mucosal antibody responses against both the major subunit of colonization factor antigen I (CFA/I) of enterotoxigenic Escherichia coli (ETEC) and the somatic lipopolysaccharide expressed by recombinant bivalent Salmonella vaccine strains were significantly enhanced by coadministration of a detoxified derivative with preserved adjuvant effects of the ETEC heat-labile toxin, LT((R192G)). The results further support the adjuvant effects of LT((R192G)) and represent a simple alternative to improve responses against passenger antigens expressed by orally delivered Salmonella vaccine strains.
Asunto(s)
Adyuvantes Inmunológicos/farmacología , Anticuerpos Antibacterianos/biosíntesis , Toxinas Bacterianas/farmacología , Enterotoxinas/farmacología , Proteínas de Escherichia coli , Escherichia coli/inmunología , Proteínas Fimbrias , Inmunidad Mucosa , Animales , Antígenos Bacterianos/administración & dosificación , Antígenos Bacterianos/genética , Proteínas Bacterianas/administración & dosificación , Proteínas Bacterianas/genética , Toxinas Bacterianas/genética , Vacunas Bacterianas/administración & dosificación , Vacunas Bacterianas/genética , Enterotoxinas/genética , Escherichia coli/genética , Lipopolisacáridos/administración & dosificación , Ratones , Ratones Endogámicos BALB C , Mutación , Salmonella typhimurium/genética , Salmonella typhimurium/inmunología , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/genéticaRESUMEN
MOTIVATION: The importance of the various kinds of repetitive nucleotide sequences for the workings of bacterial DNA has been widely recognized. This work is concerned with the distribution of a particular group of repetitive sequences, the short-sequenced interrupted extragenic palindromes, on the genetic maps of Escherichia coli K-12, Haemophilus influenzae Rd and Neisseria meningitidis Z2491 and MC58. A tool has been developed based upon a statistical hypothesis test taking into account the markovian structure of random sequences in order to determine the non-random character of extragenic palindromes. RESULTS: Totals of 7631, 12904, 4722 and 5477 non-random short interrupted palindromes have been found on the E.coli, H.influenzae, and N.meningitidis serogroup A and serogroup B genomes, respectively. Their distribution patterns on the respective genomes vary according to the bacterial species considered. Based on their position on the genome, palindromes could be distinguished as those which integrate longer, repetitive sequences; those which stand in isolation, and still others are associated to specific genome sites. AVAILABILITY: The complete list of the observed palindromes is available at the site http://www/lncc.br/~atrv. CONTACT: atrv@lncc.br
Asunto(s)
ADN Bacteriano/genética , Escherichia coli/genética , Haemophilus influenzae/genética , Neisseria meningitidis/genética , Biología Computacional , Técnicas Genéticas , Genoma Bacteriano , Análisis de Regresión , Secuencias Repetitivas de Ácidos NucleicosRESUMEN
The colonization factor antigen I (CFA/I) is one of the most epidemiologically relevant enterotoxigenic Escherichia coli (ETEC) fimbrial adhesins, which mediates the binding to human small intestine epithelium. A recombinant eukaryotic expression plasmid, pRECFA, encoding the CFA/I protein fused to the glycoprotein D of herpes simplex type 1 virus, was used to generate an antibody response in a murine model following intramuscular inoculation of purified DNA. Eukaryotic cells (BHK-21) transfected with pRECFA expressed the CFA/I protein in vitro, as revealed by Western blot and immunofluorescence microscopy. Administration of a single pRECFA 100-microg dose induced a long-term CFA/I-specific antibody response in BALB/c mice composed mainly of IgG and, to a lesser extent, IgA isotypes. The major CFA/I-specific IgG subclass was IgG2a, suggesting a Th-1-type immune response. A second dose with the same amount of purified DNA, given 2 weeks later, caused a booster effect on the immunoglobulin levels, but did not qualitatively alter the isotypes and subclasses of the induced antibody response. Immunization with different amounts of purified DNA and/or number of doses showed that maximal transient CFA/I-specific antibody levels could be obtained after two 100-microg doses of pRECFA given 2 weeks apart, but long-term antibody levels were similar.
Asunto(s)
Anticuerpos Antibacterianos/inmunología , Antígenos Bacterianos/inmunología , Proteínas Bacterianas/inmunología , ADN Bacteriano/inmunología , Escherichia coli/inmunología , Proteínas Fimbrias , Plásmidos/inmunología , Animales , Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Vacunas Bacterianas/inmunología , Línea Celular , Cricetinae , Escherichia coli/genética , Isotipos de Inmunoglobulinas , Masculino , Ratones , Ratones Endogámicos BALB C , Biosíntesis de Péptidos , Vacunación/métodos , Vacunas de ADN/inmunologíaRESUMEN
A monoclonal antibody (MAb 84) raised against the dissociated CFA/I fimbriae of enterotoxigenic Escherichia coli was characterized with regard to antigen binding and epitope specificity. Enzyme-linked immunosorbent assay (ELISA) showed that MAb 84 had higher affinity to CFA/I subunits than to intact CFA/I fimbriae and recognized a Salmonella flagellin carrying an insert corresponding to amino acids 32 to 45 of the CFA/I subunit. Fine epitope mapping based on the Pepscan technique showed that the peptide 39TFESY43, derived from the sequence of the mature CFA/I subunit, was specifically recognized by MAb 84. The 39TFESY43 sequence is probably not accessible on the surface of the native CFA/I fimbriae since MAb 84 did not bind to intact fimbriae as evaluated in inhibition ELISA tests. Moreover, MAb 84 did not agglutinate fimbriated ETEC cells nor inhibit CFA/I-mediated hemagglutination or the adhesion to Caco-2 cells.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Proteínas Bacterianas/inmunología , Epítopos/inmunología , Escherichia coli/inmunología , Proteínas Fimbrias , Fimbrias Bacterianas/inmunología , Animales , Anticuerpos Monoclonales/biosíntesis , Adhesión Bacteriana/inmunología , Proteínas de la Membrana Bacteriana Externa/inmunología , Células CACO-2/inmunología , Clonación Molecular , Mapeo Epitopo , Pruebas de Inhibición de Hemaglutinación , Humanos , Ratones , Ratones Endogámicos BALB CRESUMEN
The genetic relatedness among 29 enterotoxigenic Escherichia coli strains of serotype O6:H16 was investigated by randomly amplified polymorphic DNA (RAPD) analysis. The strains were isolated in different parts of the world, displayed CS1-CS3 or CS2-CS3 profiles, and expressed heat-labile toxin (LT) and heat-stable toxin; a single strain expressed only LT. Ten RAPD types were distinguished and showed significant similarity, having on average 82% of the amplified bands in common. These results indicated that, irrespective of the different geographical origin or virulence factors, these strains belonged to a widespread clonal group.
Asunto(s)
Toxinas Bacterianas/biosíntesis , Enterotoxinas/biosíntesis , Proteínas de Escherichia coli , Escherichia coli/clasificación , Escherichia coli/genética , Técnica del ADN Polimorfo Amplificado Aleatorio , Técnicas de Tipificación Bacteriana , Escherichia coli/patogenicidad , Infecciones por Escherichia coli/microbiología , Humanos , Filogenia , Serotipificación , VirulenciaRESUMEN
The nucleotide sequence upstream of the Escherichia coli yebG gene presents features similar to those found in SOS system regulatory sites (putative SOS box, -10 and -35 promoter boxes and a ribosome binding site). Operon fusion assays demonstrate now that this region controls transcription in a recA-, lexA-dependent way and that the reporter gene expression is inducible by DNA damage consequent to mitomycin C treatment. Increased expression does not result from an increase in plasmid copy number. These results indicate that yebG is a novel SOS regulon gene. The yebG product is predicted to be a 96 amino acid residue, 10.7 kDa protein whose function is not yet known. Unlike other SOS genes, the construct carrying the yebG regulatory region is not stationary phase inducible.
Asunto(s)
Daño del ADN/genética , Escherichia coli/genética , Genes Bacterianos , Secuencia de Bases , Secuencia de Consenso , ADN Bacteriano/genética , Escherichia coli/crecimiento & desarrollo , Escherichia coli/metabolismo , Datos de Secuencia Molecular , Operón , Regulón , Respuesta SOS en Genética/genéticaRESUMEN
The genetic diversity of 47 enterotoxigenic Escherichia coli (ETEC) strains of serotypes O6:H16, O27:H7, O29:H21, O128ac:H12, and O153:H45, previously isolated from diarrheic patients in Brazil over a period of 15 years, was investigated by random amplification of polymorphic DNA (RAPD). Informative band arrays were obtained with three 10-mer primers with G+C contents of 50, 60, and 70%. Based on the combination of the band profiles generated by the three primers 22 RAPD types were detected, and 5 major clonal clusters, each one with at least 80% identical bands, were established. The clonal clusters corresponded to strains having the same serotype which, in most cases, also had the same virulence factors (colonization factors and toxin types) and outer membrane protein and lipopolysaccharide sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles. The results suggested a correlation between phenotypic properties and genetic relatedness of ETEC isolates of human origin and indicated that a reduced number of clonally related strains are found in areas of ETEC endemicity in Brazil. Moreover, the RAPD technique revealed intraserotype-specific variations, undetectable by the combination of several phenotypic typing methods, among the ETEC strains analyzed. These results show that RAPD typing represents a useful tool for population genetics as well as for epidemiological studies of ETEC.
Asunto(s)
Enterotoxinas/análisis , Infecciones por Escherichia coli/microbiología , Escherichia coli/genética , Variación Genética/genética , Técnica del ADN Polimorfo Amplificado Aleatorio , Brasil , Preescolar , ADN Bacteriano/análisis , Diarrea/microbiología , Escherichia coli/química , Escherichia coli/clasificación , Escherichia coli/patogenicidad , Humanos , Lactante , Recién Nacido , SerotipificaciónRESUMEN
The genetic diversity in a group of Escherichia coli strains belonging to serogroup O6 but expressing different H antigens was investigated by random amplification of polymorphic DNA (RAPD). Isolates of serotypes H16, H1, H31, and non-motile (NM) strains were typed using a set of 3 primers with different G + C contents. The amplified band arrays allowed the identification of 3 main clonal clusters corresponding to each O:H serotype analyzed. Based on their RAPD profiles NM strains could be assigned to either H1 or H31 serotypes. The results indicate that the flagellar antigen and the RAPD fingerprint represent reliable clonal markers in this E. coli group.
Asunto(s)
Escherichia coli/clasificación , Dermatoglifia del ADN , Escherichia coli/genética , Variación Genética , SerotipificaciónRESUMEN
Spontaneous changes in restriction DNA profiles and pulsed-field gel electrophoresis (PFGE) patterns, along with a concomitant loss of infectivity, were observed in infective clones of Trypanosoma cruzi strain Y either following a number of passages during the exponential growth phase of after subcloning in liver infusion tryptone (LIT) medium using as the probe a genomic fragment of the parasite (pMYP16), indicating naturally occurring rearrangements of DNA sequences. No variation could be detected when the genomic DNA was probed with conserved T. cruzi tubulin and actin genes. There was no correlation between such rearrangements and the life-cycle forms of the parasites, since trypomastigote forms showed the same karyotype and hybridization patterns as did epimastigote forms. The variations observed could be reverted and infectivity, recovered after inoculation of the parasites in newborn mice.
Asunto(s)
Enfermedad de Chagas/parasitología , ADN Protozoario , Variación Genética , Genoma de Protozoos , Trypanosoma cruzi/genética , Actinas/genética , Animales , Southern Blotting , Genes Protozoarios , Cariotipificación , Ratones , Tubulina (Proteína)/genéticaRESUMEN
The affinities of six major penicillin-binding proteins (PBPs) of Yersinia pestis EV76 to different beta-lactam antibiotics were determined. The results indicate that, similar to their counterparts in Escherichia coli, PBP2 and PBP3 are the lethal targets of amdinocillin and furazlocillin, respectively. The PBP contents of four additional Y. pestis strains and the morphological effects produced by some beta-lactam antibiotics are also reported.
Asunto(s)
Antibacterianos/metabolismo , Proteínas Bacterianas , Proteínas Portadoras/metabolismo , Hexosiltransferasas , Muramoilpentapéptido Carboxipeptidasa/metabolismo , Peptidil Transferasas , Yersinia pestis/metabolismo , Antibacterianos/farmacología , Proteínas Portadoras/química , Muramoilpentapéptido Carboxipeptidasa/química , Proteínas de Unión a las Penicilinas , Unión Proteica , Yersinia pestis/efectos de los fármacos , Yersinia pestis/ultraestructura , beta-LactamasRESUMEN
Reversible changes in kinetoplast DNA (kDNA) minicircles sequences were observed in clones of Trypanosoma cruzi strain Y, following a number of passages during exponential growth phase or after subcloning in blood-free medium. kDNA restriction patterns of clones were similar to those of the original uncloned strain, while subclones presented distinct kDNA restriction patterns. Homology experiments demonstrated strong hybridization between kDNA with the same electrophoretic mobility patterns while only weak signals were observed with kDNA of different patterns. The changes observed, which are unprecedented in T. cruzi clones, characterize transkinetoplastidy, and seem to be associated with similarly reversible changes both in zymodeme and in infectivity.
Asunto(s)
ADN de Cinetoplasto/análisis , Trypanosoma cruzi/genética , Animales , Southern Blotting , Células Clonales , Enzimas de Restricción del ADN , ADN de Cinetoplasto/genética , Electroforesis en Gel de Poliacrilamida , Ratones , Hibridación de Ácido Nucleico , Trypanosoma cruzi/crecimiento & desarrolloRESUMEN
The stability of zymodemes in clonal cultures of Trypanosoma cruzi derived from strain Y was followed. Reversible changes in the isoenzyme electrophoretic mobility pattern from type A to types B and C were observed after subculturing of cloned cultures in medium of different composition or after passage in newborn mice. Type A zymodeme was observed in clones grown in blood-containing media, while types B and C were found in clones and subclones grown in media progressively less rich in nutrients (10 and 5% fetal calf serum, respectively) and containing no blood. The change in zymodeme from type A to type B or C was associated with loss of infectivity, which could be recovered by passages in newborn mice. Parasites infective for mice always showed zymodeme A. Simultaneously with zymodeme change from type A to types B and C there is a decrease in the specific activity of G6PD and 6PGD.
Asunto(s)
Isoenzimas/análisis , Trypanosoma cruzi/enzimología , Animales , Clonación Molecular , Electroforesis , Ratones , Trypanosoma cruzi/clasificación , Trypanosoma cruzi/patogenicidadRESUMEN
1. Foot-and-mouth disease virus replicase was expressed by fusing its cDNA to the OmpA signal peptide coding sequence present in the pIN-III ompA series vectors. 2. Two constructions were developed to express either a full-length or truncated enzyme lacking the 20 amino acids at the N-terminal end. Bacterial extracts expressing the recombinant proteins were submitted to SDS-PAGE and the presence of the replicase was revealed by immunoblotting. The truncated form exhibited a higher mobility and the relative positions of the proteins show that the signal peptide was removed. 3. The biological activity of these two molecules was tested using a poly(A)-dependent oligo(U)-primed poly(U)-polymerase assay. The full-length replicase is active. The aminoterminal truncated enzyme had 0.02% activity of the intact one. 4. This result indicates the importance of the twenty N-terminal amino acids for the activity of FMDV RNA-dependent RNA polymerase.
Asunto(s)
Aphthovirus/enzimología , Replicación del ADN , ADN Viral/metabolismo , ADN Polimerasa Dirigida por ADN/metabolismo , Replicación Viral , Secuencia de Aminoácidos , Aphthovirus/fisiología , Secuencia de Bases , ADN Polimerasa Dirigida por ADN/análisis , Escherichia coli/genética , Datos de Secuencia Molecular , Plásmidos , Relación Estructura-ActividadRESUMEN
1. The replicase gene of foot-and-mouth disease virus (FMDV) was expressed in Escherichia coli under the control of a tac promoter. The recombinant enzyme was purified by inclusion body precipitation, elution, and poly(U) Sepharose chromatography. 2. The enzyme exhibits poly(A)-dependent oligo(U)-primed poly(U) polymerase activity. The specific activity of the purified replicase is 1.3 x 10(5). The recombinant replicase synthesizes RNA using FMDV RNA as template, as well as heterologous RNAs, such as globin RNA and synthetic RNAs, polyadenylated or not. In all polymerization reactions, RNA products twice the size of the template are formed, both in the presence and absence of an oligo(U) primer. The enzyme is also capable of incorporating [alpha 32P]UTP in all RNAs tested except the viral template. This activity does not seem to be related to the primer independent polymerization activity. 3. The products from polymerization reactions were characterized by hybridization. In the absence of primer they consist of the template and a complementary strand covalently attached, while in the presence of primer they consist of two complementary strands synthesized de novo. 4. We propose mechanisms of RNA synthesis by the recombinant FMDV replicase in the absence and presence of primer. These mechanisms are discussed in terms of models for in vitro RNA synthesis of other picornaviruses.
Asunto(s)
Aphthovirus/genética , Replicación del ADN , ADN Viral/genética , ADN Polimerasa Dirigida por ADN/genética , Escherichia coli/genética , Regulación Bacteriana de la Expresión Génica/genética , Regulación Enzimológica de la Expresión Génica/genética , Regulación Viral de la Expresión Génica/genética , Replicación Viral , Aphthovirus/enzimología , Aphthovirus/fisiología , ADN Viral/biosíntesis , ADN Polimerasa Dirigida por ADN/análisis , ADN Polimerasa Dirigida por ADN/aislamiento & purificación , ADN Polimerasa Dirigida por ADN/metabolismo , Escherichia coli/enzimología , Regulación Bacteriana de la Expresión Génica/fisiología , Regulación Enzimológica de la Expresión Génica/fisiología , Regulación Viral de la Expresión Génica/fisiología , Plásmidos/genética , Regiones Promotoras Genéticas/genética , ARN Viral/genética , Proteínas Recombinantes/análisis , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Moldes GenéticosRESUMEN
The expression of a native form of the foot-and-mouth disease virus RNA polymerase was obtained. Two oligonucleotides of 66 base pairs were used to rebuild the 5' end of the gene and to introduce the first methionine codon. The expression of the active polymerase in E. coli was achieved by inserting the gene before the tac promoter of the pKK223-3 plasmid.
Asunto(s)
Aphthovirus/genética , ARN Polimerasas Dirigidas por ADN/genética , Escherichia coli/genética , Secuencia de Aminoácidos , Aphthovirus/enzimología , Secuencia de Bases , Clonación Molecular , Codón/genética , ARN Polimerasas Dirigidas por ADN/aislamiento & purificación , Electroforesis en Gel de Agar , Datos de Secuencia Molecular , Oligonucleótidos/química , Plásmidos , TransfecciónRESUMEN
Lactose fermenting Salmonella typhimurium are endemic in São Paulo, but not in Rio de Janeiro Two isolations are described from the latter city. These Rio de Janeiro strains have a plasmid of 7.4 megadaltons. These plasmids were not auto-transferable, were thermostable and were not eliminated by acridine orange. One of these strains arose from a plasmid that had the lactose operon repressed, leading us to speculate about the evolution of the lactose fermenting character in Brazilian Salmonella.
Asunto(s)
Factores de Lactosa/genética , Lactosa/metabolismo , Plásmidos/genética , Factores R/genética , Salmonella typhimurium/genética , Brasil , Conjugación Genética , Fermentación , Factores de Lactosa/fisiología , Factores R/fisiología , Salmonella typhimurium/metabolismoRESUMEN
A set of 25 multiple drug-resistant strains selected from Salmonellae isolated from sewage in Rio de Janeiro contained S. typhimurium (60%) and S. agona (20%) as the most frequent serotypes. There was resistance to ampicillin (Ap), 92%; chloramphenicol (Cm), 76%; gentamicin (Gm), 84%; kanamycin (Km), 84%; streptomycin (Sm), 96%; tetracycline (Tc), 76%; trimethoprim-sulfamethoxazole (SuTp), 84% and nalidixic acid (Na), 52%. The most frequent resistance patterns observed were Ap Cm Gm Km Sm Tc SuTp Na and Ap Cm Gm Km Sm Tc SuTp. Two strains, bearing the streptomycin, tetracycline double-resistance pattern were colicinogenic, producing type Ib colicin. The col+ character was cotransferable with the double-resistance; all these markers were associated with the presence of a single 60 Mdal plasmid.
Asunto(s)
Antibacterianos/farmacología , Plásmidos , Salmonella/genética , Plásmidos de Bacteriocinas/efectos de los fármacos , Farmacorresistencia Microbiana , Electroforesis en Gel de Agar , Factores R/efectos de los fármacosRESUMEN
A Salmonella agona strain has caused a hospital outbreak of gastroenteritis in a pediatric unit in Rio de Janeiro. It bears two plasmids, a small (6.5 MDa molecular weight) plasmid coding for type B colicin production and a larger one (36 MDa molecular weight) determining resistance to ampicillin, gentamicin, kanamycin and trimethoprim-sulphamethoxazole. The R-plasmid, but not the Col-plasmid, is self-transferable to a Escherichia coli recipient strain. Curing for the R-plasmid was achieved by treatment with 0.05% SDS followed by incubation at 44 degrees C. It has not been possible to cure the S. agona strain for its Col-plasmid.