[Cystocele and perineal ultrasound : Comparison of reliability and patient satisfaction]. / Zystozele und perinealer Ultraschall : Vergleich von Reliabilität und Patientenzufriedenheit.

BACKGROUND: Pelvic organ prolapse is a common medical finding. The use of perineal ultrasound for diagnosis of cystoceles is gaining in importance. OBJECTIVES: The purpose of this work was to test whether perineal ultrasound can be used to diagnose a cystocele before surgery and for follow-up examination. Furthermore, patient satisfaction during speculum examination and perineal ultrasound was compared. MATERIALS AND METHODS: 33 women with cystocele were examined before and after anterior colporrhaphy. Symptoms and satisfaction were documented with questionnaires. RESULTS: Ultrasound measurements of both examiners were correlated before and after colporrhaphy. Also, the degree of cystocele and ultrasound were correlated during Valsalva after surgery. There was no clear relation between typical symptoms of the cystocele and ultrasound measurements. The patient's comfort is higher during ultrasound than during speculum examination (r = 0.45; p = 0.04. t = 4,418; p < 0.01). CONCLUSION: The results of the perineal ultrasound are reproducible before and after colporrhaphy. Patients prefer ultrasound to the speculum examination. A sonographic scale of the cystocele would extend the use of perineal ultrasound.

La sexuación en hijos de hombres homoeróticos: análisis de un caso / Sexuation in children of a homoerotic men couple: case of study

El presente artículo es producto de una investigación de doctorado de corte cualitativo y con enfoque psicoanalítico. Se proponen cuatro momentos de la sexuación en la hija de una pareja de hombres homoeróticos y se abordan a profundidad los primeros dos momentos. La sexuación es entendida como la posibilidad de que alguien llegue a declarar un sexo y una elección de partenaire sexual. Los primeros vínculos, las asignaciones provenientes del otro y la separación-interdicción que pone límite al goce incestuoso entre padres e hijos son aspectos que juegan un papel decisivo en la sexuación. Dentro de los cuatro momentos de la sexuación se encuentran articulados tres planos de la diferencia localizables en el caso, estos son: la diferencia niño-adulto, la diferencia de género y la diferencia de los sexos. La articulación de estos tres planos de la diferencia, abre la posibilidad de pensar en posicionamientos sexuados diversos y singulares que cuestionan los esencialismos y las dicotomías tradicionales.

The present article is a qualitative research result. It proposes, from the psychoanalytic perspective, four sexuation moments for the daughter of a homoerotic men couple. Sexuation is defined as the process a person goes through to identify themselves with a sex and choosing a sexual partner. In this matter, the first relationships, the assignations of the other and the separation-interdiction that puts a limit to the incestuous pleasure between parents and children are factors that play a key role in sexuation. In the four moments of sexuation, there are articulated three difference levels: the child-adult difference, the gender difference and the difference between sexes. The configuration of these three difference levels, allows the possibility to think about diverse and unique sexual identity placements that challenge the traditional dichotomy.

Modelización de ítems de matrices figurales y pautas específicas propuestas para su construcción / Modelling figural matrix items and specification of guidelines for their construction

Este artículo da a conocer los resultados de la modelización de un Test de Analogías Figurales (TAF) utilizando los aportes conjuntos de la Teoría Clásica de Tests (TCT) y de la Teoría de Respuesta al Ítem (TRI), así como la posterior interpretación de las desventajas y posibles soluciones del diseño de dicho test. Se desarrolla el marco conceptual que dio origen al armado del TAF, así como los estudios realizados con esta prueba al administrarla a dos muestras. Una de las muestras corresponde a un estudio piloto con estudiantes de Psicología, mientras que la otra muestra consistió en estudiantes de carreras artísticas y de diseño. Los resultados principales revelan indicadores favorables de unidimensionalidad y confiabilidad, así como parámetros aceptables de discriminación (a), dificultad (b) y pseudoazar (c). Se discuten las desventajas del diseño de ítems con tres reglas y nuevas especificaciones en cuanto al armado de reactivos matriciales de 2x2

This manuscript publicizes the results that concern the modelling of a Test of Figural Analogies (TFA) using Classical Test Theory (CTT) and Item Response Theory (IRT) on a joint basis, as well as the interpretation of the disadvantages and possible solutions of the test design. The theoretical background for the TFA construction is outlined, and studies accomplished after its administration to two samples is explained. One of these samples corresponds to a pilot study with Psychology students, while the other sample consisted of Art and Design college students. Main results indicate good unidimensionality and reliability, as well as acceptable discrimination (a), difficulty (b) and guessing value (c) parameters. Design disadvantages of three-rule based items are discussed, and new specifications for the 2x2 matrix item construction are given

Evaluation of a modified EUCAST fragmented-mycelium inoculum method for in vitro susceptibility testing of dermatophytes and the activity of novel antifungal agents.

For antifungal susceptibility testing of nonsporulating or poorly sporulating dermatophytes, a fragmented-mycelium inoculum preparation method was established and compared to broth microdilution testing according to CLSI and EUCAST guidelines. Moreover, the in vitro activity of new antifungal agents against dermatophytes was evaluated. Agreement between the mycelial inoculum method and the CLSI broth microdilution method was high (93% to 100%). Echinocandins (minimal effective concentration [MEC], ≤0.5 mg/liter) and posaconazole (MIC, ≤3.00 mg/liter) showed good activity against all tested dermatophytes.

A novel cysteine cathepsin inhibitor yields macrophage cell death and mammary tumor regression.

Although cysteine cathepsins have been identified as key regulators of cancer growth, their specific role in tumor development remains unclear. Recent studies have shown that high activity levels of tumor cathepsins are primarily a result of increased cathepsin activity in cancer-promoting tumor-associated macrophages (TAMs). To further investigate the role of cysteine cathepsin activity in normal and polarized macrophages, we established in vitro and in vivo models of macrophage differentiation and polarization and used a novel cysteine cathepsin inhibitor, GB111-NH2, to block the activity of cathepsins B, L and S. Here we show that in vitro, cysteine cathepsin inhibition yields both apoptosis and proliferation of macrophages, owing to increased oxidative stress. Proteomic analysis of cathepsin- inhibited macrophages demonstrates inhibition of autophagy, suggesting a likely cause of elevated reactive oxygen species (ROS) levels. In vivo models of mammary cancer further show that cathepsin inhibition yields TAM death owing to increased ROS levels. Strikingly, apoptosis in TAMs yields a seemingly cell non-autonomous death of neighboring cancer cells, and regression of the primary growth. These results show that cysteine cathepsin inhibitors can specifically trigger macrophage cell death and may function as an effective anticancer therapy in tumors with high levels of TAMs.

Cuidar no como una buena madre: análisis de un niño de 5 años con serios problemas de conducta / Taking care not like a good mother: analysis of a five-year-old child with a serious conduct problem

Existen formas de maltrato infantil que culturalmente no se consideran como tales por ser aparentemente inofensivas, pero que Raskovsky (1975[1970]) llama formas atenuadas del filicidio. Aunque sus efectos varían de acuerdo con las circunstancias particulares, puede suponerse que para el aparato psíquico representan un exceso de Qή (Freud, 1895) que debe expulsar por cualquier medio: a menudo, conductas agresivas. Aquí se presenta el caso de un niño de 5 años sometido al enojo de la madre, quien lo dejaba inerme ante su tensión o la intensificaba con sus regaños, dejándolo así sin la posibilidad de metabolizar dicha tensión. En este trabajo se analiza la historia del niño y sus producciones en sesiones de observación y tratamiento siguiendo la línea de Bleichmar (1993, 1999).

There are forms of child mistreatment that culturally are not considered as such by being seemingly harmless, but Raskovsky (1975[1970]) called them attenuated forms of filicide. Although its effects vary according to particular circumstances, it may be supposed that it means an excess of Qή (Freud, 1895) for the psychic apparatus that must be drained out anyhow: often, through aggressive behavior. Here we report the case of a 5 years old boy exposed to the mother’s anger; she left him helpless against his tension states or intensified them through her scolding, leaving no chance to metabolize the tension. This paper analyzes the child history and his productions through observation ant treatment sessions following Bleichmar’s (1993, 1999) views.

In vitro and in vivo role of heat shock protein 90 in Amphotericin B resistance of Aspergillus terreus.

Aspergillus terreus (A. terreus) is of serious concern because of a high propensity to dissemination and in vitro and in vivo resistance to Amphotericin B (AmB). The underlying molecular mechanism of AmB is not known yet and here we want to explore whether fungal heat shock protein 90 (HSP90) is involved in polyene resistance in A. terreus. AmB-susceptible (ATS) and AmB-resistant (ATR) A. terreus and AmB-susceptible Aspergillus fumigatus (AFS) were investigated in response to AmB with a special focus on HSP90. HSP90 inhibitors resulted in significant improvement of AmB activity against ATR as minimum inhibitory concentrations (MIC) decreased from 32 to 0.38 mg/L. Gene expression profiling showed a greater basal amount of HSP90 levels in ATR and ATS when compared with AFS. HSP90 blockers in combination with AmB were evaluated in a murine model of disseminated aspergillosis. HSP90 inhibitors were not beneficial for mice infected with ATR, and neither mono- nor combination treatment with AmB yielded clinical improvement. HSP90 inhibition with 17-allylamino-17-demethoxygeldanamycin (17-AAG) was harmful. HSP90 seems to play a vital role in antifungal stress response in all aspergilli tested, whereas HSP90 does not substantiate the origin of AmB resistance in ATR.

Species and susceptibility distribution of 1062 clinical yeast isolates to azoles, echinocandins, flucytosine and amphotericin B from a multi-centre study.

Descriptive values were determined for eight antifungal agents within the course of a multi-centre study encompassing 1062 German and Austrian clinical yeast isolates. Candida albicans (54%) was the predominant species isolated followed by Candida glabrata (22%), Candida parapsilosis (6%), Candida tropicalis (5.7%), Candida krusei (4.3%), as well as eleven further candidal and four non-Candida yeast species. While 519 (48.9%) isolates were tested susceptible to all antifungals tested, no isolate was found to exhibit complete cross resistance. For C. albicans, the proportions of susceptible isolates were 93.2% (amphotericin B), 95.6% (flucytosine), 84.3% (fluconazole), 83.8% (posaconazole), 91.8% (voriconazole), 96.5% (anidulafungin), 96.2% (caspofungin) and 97.6% (micafungin). Patterns of complete parallel resistances were observed within azoles (8.8%) and echinocandins (1.7%). While a decreased susceptibility was found infrequently for echinocandins and flucytosine, it was more common for azoles with highest proportions for isolates of C. glabrata (fluconazole, 40.6%; posaconazole, 37.2%), Candida guilliermondii (fluconazole and posaconazole, each 25.0%), C. krusei (posaconazole, 28.3%; voriconazole, 60%), C. parapsilosis (fluconazole, 70.3%) and C. tropicalis (fluconazole, 62.3%). The descriptive values obtained in this study represent a valid basis for the comparison of recent and future epidemiological surveys to analyse the susceptibility of yeast isolates towards major antifungal substances.

Analogías de figuras: Teoría y construcción de ítemes / Figural analogies: Theory and construction of items

Se describen las bases conceptuales y operacionales de los tests de resolución de problemas por analogía estableciendo énfasis en las analogías de figuras. Se expone brevemente la importancia del estudio de dicho constructo hipotético para el abordaje de la capacidad intelectual. Se citan lineamientos teóricos sobre el mismo y se describen las características y mecanismos cognitivos fundamentales implicados en la resolución de matrices de figuras. En cuanto a este último punto, se aborda la comprensión de las relaciones y correlatos entre relaciones figurales tomando el modelo de proporción A:B::C:D propio de la tradición psicométrica desde principios del Siglo XX. Se establecen además vínculos conceptuales con aportes de autores pertenecientes a la vertiente cognitiva de estudio del razonamiento analógico y con escuelas de la Psicología General. Se pretende brindar un marco ideal para la creación de matrices figurales de 2 x 2 que midan el constructo. Con el objetivo de evitar sesgos en la medición, se plantean seis sugerencias básicas puestas al servicio tanto de la confección de estos reactivos, como de su administración. Dichas sugerencias son las siguientes: (1) considerar el doble camino de resolución de la matriz, (2) desarrollar una estrategia unívoca de resolución, (3) tomar en cuenta n estrategias para generar nk ítemes, (4) crear ítemes a ser resueltos únicamente por la vía del razonamiento analógico, (5) consideraciones en cuanto a las opciones de respuesta y (6) consideraciones referidas a la administración.

This paper describes the conceptual and operational bases of analogical problem - solving tests, placing emphasis on figural analogies. The importance of the study of such a hypothetical construct to the understanding of intellectual capacity is briefly outlined. The significance of the construct in relation to mental development and individual maturation from childhood to adulthood is also explained in a concise way. Theoretical considerations about analogical reasoning are quoted and the fundamental characteristics and cognitive mechanisms involved in the resolution of figural matrix items are described. In this respect, the nature of relations and correlations between relations of figures is elucidated taking into account the A:B::C:D proportional model which has been researched by psychometrists since the beginning of the 20th Century. This model suggests the existence of two pairs of relations between elements, where element A is to element B as element C is to a missing element D (Figure 2). Items created on the basis of this structure usually contain given answers, only one of which is correct. On the other hand, linkages are established with contributions from experts defending the cognitive perspective of the study of analogical reasoning, and also with General Psychology schools like Gestalt and Gardner's theory of multiple intelligence. Finally, an ideal framework for the creation of 2 x 2 figural matrices that can measure analogical reasoning is intended to be provided. With the purpose of reducing item bias, six essential suggestions for the preparation and administration of items are offered. These suggestions are: (1) the constructor should consider the double resolution pathway of a proportional analogy (horizontal as well as vertical, i.e. A:B::C:D and A:C::B:D). In doing so, the probability of generating non-controlled rules of analogical relation to one of these pathways will be reduced. These accidental rules correspond to resolution logics different from those chosen by the designer, therefore affecting item manipulation and control. (2) Strongly related to the latter, given that each rule or combination of rules creates one different resolution strategy, each proportional analogy item should incorporate only one of these strategies to be applied horizontally as well as vertically. (3) Given that one or more rules may be used for the same item, a few rules are more than enough to prepare a large group of strategies and, therefore, a large item bank. Also, it is possible to take into account n strategies to produce nk items, being k the number of items apparently different from each other that nevertheless share the same resolution strategy. (4) Items that can be solved by applying ways of reasoning different from those of the proportional analogies should not be constructed. For instance, the designer should not allow superficial comparisons among some matching attributes of the item as a problem solving method, since this procedure does not require the consideration of the whole matrix structure (Gestalt's) which should serve as a basis for the analogical reasoning task. Therefore, pairing analogies should be rejected as they allow for this kind of resolution pathways (e.g. matching circle C with circle D2 in the 4th item of Figure 2, without taking into account the other matrix figures). (5) Alternative responses should contain one clearly correct answer to be discovered by using only analogical reasoning; wrong answers should not replace the correct one just because they are more appropriate considering alternative non-pretended ways of reasoning; all alternatives should share similarities and be distributed on a random basis. (6) The bias arising from administration conditions should be taken into account, including the possible verbal contamination during completion of this non-verbal test.

Revisión de investigaciones recientes sobre la aplicación de la Teoría de Respuesta al Ítem al Child Behavior Checklist / Revision of recent investigations about the application of Item Response Theory to the Child Behavior Checklist

El Child Behavior Checklist (CBCL) es un formulario que permite registrar problemas comportamentales y competencias sociales de niños y adolescentes. Si bien se construyó desde el enfoque clásico de la Teoría de los Test, investigaciones recientes mostraron la utilidad de aplicar la Teoría de Respuesta al Ítem (TRI) para modelizar las variables del CBCL. El desarrollo de este trabajo revisa las consideraciones que se vieron obligados a tomar los respectivos autores para cumplir con las exigencias de los modelos de la TRI. Se describe la información que brindan las Curvas Características de los Ítems y cómo su análisis podría contribuir para optimizar el tiempo de administración del CBCL. Asimismo, se sintetizan los resultados alcanzados en relación con el estudio de la invarianza de las medidas obtenidas a través de adaptaciones transculturales de este formulario.

The Child Behavior Checklist (CBCL) is a questionnaire that allows the assessment of behavioral problems and social competences of children and adolescents. Although it was developed on the basis of the classical approach of the Test Theory, recent investigations have revealed the usefulness of applying the Item Response Theory (IRT) to model the variables of CBCL. This paper revises the considerations made by the respective authors in order to meet the demands of the IRT models. The information provided by the Characteristic Curves of Items is described as well as the manner in which the analysis thereof might contribute to optimize the administration period of CBCL. Furthermore, the invariance of the measures obtained through transcultural adaptations of this questionnaire is analyzed and the results are summarized.

Factores de personalidad predictores de la disposición para la venta: Un estudio exploratorio con postulantes laborales / Personality factors that predict sale readiness: An exploratory study with industrial applicants

La presente investigación tuvo por objetivo detectar variables predictoras de la Disposición General para la Venta (DGV) y de los Estilos Receptivo y Agresivo de Venta partiendo del análisis de las correlaciones entre variables de personalidad del vendedor y otros factores de personalidad, factores sociodemográficos y Cociente Intelectual (CI). Se tomó una muestra de 33 postulantes a vendedor con edades entre 23 y 57, 94% hombres, a los que se administró el Inventario de Personalidad para Vendedores (IPV), el Cuestionario de 16 Factores de Personalidad (16 Personality Factor, PF) versión 5 y el Test de Factor General (G). Los resultados principales arrojan correlaciones significativas entre DGV e Independencia (r = .39, p = .02) y entre Estilo Receptivo de Venta y Dureza (r = -.48, p < .01). Tanto la DGV como los estilos de venta del IPV no varían significativamente con Edad, Nivel de Estudios o CI. Estos hallazgos son aplicables a la selección a corto plazo de personal comercial calificado.

The goal of the present research was to find predictive variables for the General Sale Readiness (GSR) and the Receptive and Aggressive Sale Styles by making correlational analysis among salesmen personality variables and other personality factors, sotiodemographic factors and Intelligence Quotient (IQ). A sample of 33 applicants for sales jobs aged 23 to 57 with 94% of men was taken and evaluated with the Salesmen Personality Inventory (SPI), the 16 Personality Factor 5th version Questionnaire and the General (G) Factor Test. Main results show significant correlations between GSR and Independence (r = .39, p = .02) and between Receptive Sale Style and Tough-Mindedness (r = -.48, p < .01). The GSR and the Sale Styles of the SPI do not vary significantly with Age, Studies Level or IQ. These findings are applicable to the short term selection of qualified commercial personnel.

A 1-year Aspergillus terreus surveillance study at the University Hospital of Innsbruck: molecular typing of environmental and clinical isolates.

Aspergillus terreus appears to have become an increasingly frequent cause of opportunistic infections in the University Hospital of Innsbruck (UHI) and is of serious concern because of in vivo and in vitro resistance to amphotericin B. In order to determine the possible relationship between environmental contamination by A. terreus and the occurrence of invasive aspergillosis, a 1-year prospective study (2004-2005) was carried out in the UHI. Isolates obtained from air samples of various high-risk settings and those from surveillance cultures of proven and probable aspergillosis (EORTC/MSG criteria) were examined by genotyping. Within 1 year, 34 and 15 A. terreus isolates were collected from the environment and from patients, respectively. Genotypic analysis with rapid amplification of polymorphic DNA (RAPD) PCR and the combination of three different primers (R108, CII, P4) revealed 46 distinct genotypic profiles (types 1-46). No strain similarity was detected among and within the patients and environmental areas, indicating a great genomic diversity in A. terreus, which is common in the environment of Innsbruck and a source of invasive infections in immunosuppressed patients. Genotypical diversity was found in clinical and environmental A. terreus isolates.

Influence of amphotericin B and amphotericin B colloidal dispersion on the functions of human phagocytes in defence against Aspergillus species.

This study investigated the in vitro effects of amphotericin B and amphotericin B colloidal dispersion (ABCD) on phagocytosis and inhibition of germination of clinical isolates of Aspergillus spp. by monocyte-derived macrophages (MDMs). Both amphotericin B and ABCD caused significant reductions in uptake of conidia of Aspergillus spp. by MDMs (p < 0.01). The inhibition of germination was superior with conidia of Aspergillus fumigatus, Aspergillus niger and Aspergillus terreus isolates. Aspergillus flavus growth was significantly less inhibited of either antimycotic as compared to A. fumigatus and A. terreus (p < 0.01).We demonstrate that amphotericin B or ABCD acts as a potent inhibitor of Aspergillus germination. By contrast, treatment of MDMs with these antimycotics diminished phagocytosis of conidia in vitro.

Substrate competitive inhibitors of IGF-1 receptor kinase.

IGF-1 and its receptor play a pivotal role in many cancers, and therefore, IGF-1R is an attractive target for the design of inhibitors. In this communication, we report on a number of lead compounds for inhibitors of the isolated IGF-1R kinase. The search for these compounds utilized two novel in vitro assays and was aided by the knowledge of the three-dimensional structure of the insulin receptor kinase domain, which is 84% homologous to the IGF-1R kinase domain. The most potent inhibitor found in these assays was tyrphostin AG 538, with an IC(50) = 400 nM. In computer modeling, AG 538 was placed in the kinase domain of the insulin receptor and was able to sit in place of tyrosines 1158 and 1162, which undergo autophosphorylation. Experimentally it is indeed found that AG 538 does not compete with ATP but competes with the IGF-1R substrate. We prepared I-OMe AG 538, which is more hydrophobic and less sensitive to oxidation than AG 538. Both AG 538 and I-OMe AG 538 inhibit IGR-1R autophosphorylation in intact cells in a dose-dependent manner but I-OMe-AG 538 is superior, probably because of its enhanced hydrophobic nature. Both compounds inhibit the activation of the downstream targets PKB and Erk2. These findings suggest that AG 538 and I-OMe-AG 538 can serve as a lead compound for the development of substrate competitive inhibitors of the IGF-1R. The possible advantage of substrate competitive inhibitors vis-à-vis ATP competitive inhibitors is discussed.

Leading ruelle resonances of chaotic maps

The leading Ruelle resonances of typical chaotic maps, the perturbed cat map and the standard map, are calculated by variation. It is found that, excluding the resonance associated with the invariant density, the next subleading resonances are, approximately, the roots of the equation z(4)=gamma, where gamma is a positive number that characterizes the amount of stochasticity of the map. The results are verified by numerical computations, and the implications to the form factor of the corresponding quantum maps are discussed.

Intraosseous is faster and easier than umbilical venous catheterization in newborn emergency vascular access models.

The purpose of this study is to compare the speed and ease of establishing newborn emergency vascular access using intraosseous (IO) versus umbilical venous catheterization (UVC). The study is an experimental design. A total of 42 medical students, without prior IO and UVC experience, were recruited as study subjects. All subjects performed the UVC procedure and were randomized (by a coin flip) to perform the IO procedure in one of two models: (1) turkey bone or (2) plastic infant leg. Each subject performed an initial trial for both the IO and UVC procedures without practice ("Inexperienced attempt") and a second trial in both procedures after practice ("Experienced attempt"), such that in total, each subject completed four attempts (two IO and two UVC). IO and UVC placement times were measured, and placement difficulty scores for IO and UVC were measured using a 10 cm visual analog scale (VAS). The averaged elapsed time to successful access was significantly shorter for the IO procedure on both the initial "inexperienced" attempt (52 versus 134 seconds, P < .001) as well as the "experienced" attempt (45 versus 95 seconds, P = .011). Procedure difficulty scores were lower in the IO procedure for both "inexperienced" and "experienced" attempts (3.5 versus 5.5, P = .001 and 2.6 versus 4.7, P < .001) as measured on a 10 cm VAS. Although UVC may be preferred by neonatologists, this model suggests that IO results in easier and more rapid vascular access in those who do not frequently perform newborn resuscitation. As such, the benefit of teaching UVC in pediatric resuscitation courses should be reconsidered. The recommended method of emergency newborn vascular access should be reconsidered pending further studies on this subject.

Characterization of Escherichia coli strains isolated from environmental water habitats and from stool samples of healthy volunteers.

This study was undertaken to determine the frequency of pathogenic Escherichia coli strains among wild-type E. coli strain isolates from the microbial flora of healthy volunteers and from natural residential water habitats of a defined geographic area. In total, 131 stool and 95 water isolates as well as 14 E.coli K12 strains were examined for DNA sequences specific for 20 different genes encoding E. coli pathogenicity factors, including adherence factors, toxins, invasins, capsules and iron uptake systems. The expression of the corresponding pathogenicity factors was also investigated. No pathogenicity factors were found to be present in the tested E. coli K12 strains. In contrast, 41.0% of the water samples and 63.4% of the stool samples contained pathogenicity factors specific for extraintestinal E. coli pathogens. While no virulence determinants specific for intestinal E. coli pathogens were found among the investigated environmental water isolates, 4.5% of the stool samples contained either only intestinal or both intestinal and extraintestinal virulence genes. Both the prevalence of the virulence genes and the expression of the corresponding pathogenicity factors were, in general, higher in stool than in water samples. These findings might indicate the prevalence of different clonal types and/or differential regulation of pathogenicity factor expression in diverse ecological niches.

Comparative methodology to investigate the presence of Escherichia coli K-12 strains in environmental and human stool samples.

This study was undertaken to evaluate the specificity and efficiency of different methods to detect Escherichia coli K-12 strains. Another aim was to determine the frequency of E. coli K-12 strains among wild-type E. coli isolates from different sources. The detection of K-12 strains was performed both genotypically by K-12 specific polymerase chain reaction (PCR) and on the basis of phenotypical tests. In addition, the genome structures of E. coli strains were characterized by pulsed-field gel electrophoresis (PFGE). The most specific results could be obtained by the genotypical tests PCR and PFGE as well as by the K-12 specific phage assay. In total, 131 stool and 95 water isolates as well as 14 K-12 derivatives were examined by the different methods. No E. coli K-12 strains were detected among the wild-type isolates.

Properties of Escherichia coli strains of serotype O6.

Escherichia coli isolates of serotype O6 show a broad spectrum of virulence: virulent strains often cause urinary tract infections; other strains are considered nonpathogenic. In order to analyze the properties of E. coli O6 strains, different phenotypic and genotypic test systems were used. Our data indicate that O6 strains represent a rather heterogenous group of bacteria, which differ in the genotypic presence as well as in the phenotypic expression of virulence factors. In contrast to the isolates 536 (O6:K15) and RZ 475 (O6:K5) the strain DSm 6601, belonging to serotype O6:K5:H1, produces neither toxins nor mannose-resistant hemagglutinating (MRHA) adhesins. However, the strain possesses chromosomally located gene clusters coding for F1C (foc) and type I fimbriae (fim). In addition, the strain secrets the iron-uptake substances aerobactin and enterobactin and produces at least one microcin. The strain is serum-sensitive and is less virulent in in vivo animal tests.

tRNA genes and pathogenicity islands: influence on virulence and metabolic properties of uropathogenic Escherichia coli.

The uropathogenic Escherichia coli strain 536 (O6:K15:H31) carries two unstable DNA regions on its chromosome which were termed pathogenicity islands (Pais). Both pathogenicity islands, Pai I and Pai II, are incorporated into tRNA specific loci: Pai I is located in the tRNA gene for selenocysteine (selC), and Pai II is integrated in the leucine-specific tRNA locus leuX. Mutant strain 536-21 has lost the two pathogenicity islands together with the intact tRNA genes. While 536 is a virulent strain, 536-21 has lost a number of properties, including in vivo virulence. In previous publications we reported that the genes coding for two haemolysins (hly I, hly II) and P-related fimbria (prf) are located on the Pais. In this paper, we demonstrate that the expression of other gene products influencing metabolic properties in addition to in vivo virulence are strongly dependent on the intact tRNA loci selC and leuX. In order to determine the influence of the two tRNAs on the expression of these properties, the genes selC and leuX were cloned from the genome of strain 536 and then introduced into the mutant 536-21. Our results clearly show that the seleno-cysteine-specific tRNA (tRNA(Sec)) directly influences the ability of the bacteria to grow under anaerobic conditions, because selenocysteine is part of the enzyme formate dehydrogenase (FDH) which is involved in mixed acid fermentation. The rare leucine-specific tRNA5(Leu), encoded by leuX, influences a number if properties including type 1 fimbria production, flagellation and motility, production of enterobactin and serum resistance, and is also necessary for full in vivo virulence. While the tRNA(Sec) is directly involved in the production of FDHs, the leuX specific tRNA5(Leu) appears to influence the expression of various factors through specific transcriptional or translational control mechanisms.