Isolation of atypical enteropathogenic Escherichia coli from chicken and chicken-derived products.

Atypical enteropathogenic Escherichia coli (EPEC) strains from chicken and chicken-derived products were isolated and characterised. The strains presented a wide variety of serotypes, some have been reported in other animal species (O2:H40, O5:H40) and in children with diarrhoea (O8:H-). Most of the strains carried intimin ß. The results indicate that chicken and chicken products are important sources of atypical EPEC strains that could be associated with human disease, and highlight the need to improve hygiene practices in chicken slaughtering and meat handling.

Short communication: characterization of Shiga toxin-producing Escherichia coli isolated from newborn, milk-fed, and growing calves in Argentina.

Shiga toxin-producing Escherichia coli (STEC) cause foodborne pathogenic disease that is shed in the feces of cattle. The aim of this study was to evaluate how early young calves are colonized by STEC strains, potentially pathogenic for humans, and the prevalence in different calf categories. From 808 rectal swabs analyzed by PCR, 38% were stx positive. The prevalence in newborn (<24 h from birth), milk-fed (<2-mo-old), and growing calves (2-8 mo old) were 25, 43, and 58%, respectively. Forty different STEC serotypes were found among isolates from newborn, milk-fed, and growing calves that shed STEC strains potentially pathogenic for humans. The STEC strains could be acquired early from mothers, enabling the infection of other animal categories and confirming the risk to public health.

Characterization of Shiga toxin-producing Escherichia coli isolated from dairy cows in Argentina.

AIMS: To feno-genotypically characterize the Shiga toxin-producing Escherichia coli (STEC) population in Argentinean dairy cows. METHODS AND RESULTS: From 540 STEC positive samples, 170 isolates were analyzed by multiplex PCR and serotyping. Of these, 11% carried stx1, 52% stx2 and 37% stx1/stx2. The ehxA, saa and eae were detected in 77%, 66% and 3%, respectively. Thirty-five per cent of strains harboured the profile stx1, stx2, saa, ehxA and 29% stx2, saa, ehxA. One hundred and fifty-six strains were associated with 29 different O serogroups, and 19 H antigens were distributed among 157 strains. STEC O113:H21, O130:H11 and O178:H19 were the most frequently found serotypes. The STEC O157:H7 were detected in low rate and corresponded to the stx2(+) , eae(+) , ehxA(+) virulence pattern. CONCLUSIONS: We detected a diversity of STEC strains in dairy cattle from Argentina, most of them carrying genes linked to human disease. SIGNIFICANCE AND IMPACT OF THE STUDY: The non-O157 STEC serotypes described in this study are associated worldwide with disease in humans and represent a risk for the public health. For this, any microbiological control in dairy farms should be targeted not only to the search of O157:H7 serotype.

Occurrence of Shiga toxin-producing E. coli (STEC) on carcasses and retail beef cuts in the marketing chain of beef in Argentina.

Argentina has the highest incidence of HUS in the world. HUS is produced by STEC O157 and non-O157. Cattle's faeces and hides are sources of STEC contamination of carcasses during slaughter. We investigated the presence of STEC in carcasses and cuts of meat in the marketing chain in an agricultural city located in Buenos Aires Province (Argentina). In this study, the detection of the stx gene was used as an indicator of carriage of meat with STEC. In carcasses, we detected 12.34% and 18.64% of STEC at the slaughter and sanitary control cabin (place where carcasses arrive from slaughters located outside the city), respectively. These percentages increased at butcheries (24.52%). The 25% of retail beef cuts were STEC-positive with significant differences among the different cuts of meat (chuck: 12.12%, rump roast: 12.12% and minced beef: 40.74%). The stx2 gene was the predominant gene detected in all samples at different levels of the commercialization meat chain.

Development of a new photoelectron spectroscopy instrument combining an electrospray ion source and photoelectron imaging.

A new apparatus has been constructed that combines electrospray ionization with a quadrupole mass filter, hexapole ion trap, and velocity-map imaging. The purpose is to record photoelectron images of isolated chromophore anions. To demonstrate the capability of our instrument we have recorded the photodetachment spectra of isolated deprotonated phenol and indole anions. To our knowledge, this is the first time that the photodetachment energy of the deprotonated indole anion has been recorded.

Complete characterization of the (D2O)2 ground state: high Ka rotation-tunneling levels.

We report the observation of extensive a- and c-type rotation-tunneling (RT) spectra of (D2O)2 for Ka = 0-4. These data allow quantification of molecular constants and tunneling splittings for a number of previously unobserved RT states of (D2O)2. The vibrational ground state has thus been characterized to energies as high as those of some of the intermolecular vibrations, and we present the first test of the VRT(ASP-W) potential at these high Ka states.

Toxigenic Escherichia coli isolated from pigs in Argentina.

The presence of porcine toxigenic E. coli (ETEC, VTEC) in 28 piggeries (5% of total) of the central and northeast region of Argentina was studied for a better understanding of the epidemiology of porcine strains. Samples were taken by rectal swabs from healthy piglets and from those with diarrhoea, in addition to their dams. Between 5-10 colonies were isolated from each one of 223 animals sampled from 1992 to 1997. By using specific primers each strain was screened by PCR for VT1, VT2all, VT2e, STIa, and LTI toxin genes. Only strains positive for any of the toxins mentioned above were screened for STb. Their O serogroups were determined by agglutination. All of the above enterotoxins and verocytotoxins were found in E. coli isolated from the animals. The STIa gene was detected in E. coli isolated from 27/127 piglets with diarrhoea, in comparison with LTI (4/127 pigs). No toxin gene was amplified from E. coli isolated from either healthy piglets or their dams. When strains isolated from 48 piglets without diarrhoea but showing delayed growth were analysed by PCR, their toxin profile was determined to be VT1 (1/48 piglets), VT2all (5/48), STIa (1/48), LTI (3/48) and VT2e (3/48). Serogroup O64 prevailed among ETEC; O138 prevailed for ETEC/VTEC strains. This is the first extensive study regarding porcine toxigenic E. coli in Argentina and constitutes an important database for the implementation of prevention measures.

Virulence genotypes and serotypes of verotoxigenic Escherichia coli isolated from cattle and foods in Argentina. Importance in public health.

Virulence factors of Verotoxin-producing Escherichia coli (VTEC) strains isolated from hamburgers and ground beef were studied in Argentina by PCR. Their virulence profiles were correlated with those corresponding to strains isolated from calves and adult cattle. Most virulent profiles (VTs+ eae+ Mp+) were present in E. coli from healthy and diarrheic calves corresponding to O5:H-, O5:H27, O20:H?, O26:H11, O38:H?, O103:H-, O103:H2, O111:H-, O118:H16, O165:H-serotypes. The presence of the eae gene was significantly more frequent among VTEC strains isolated from calves (20/26; 76%) than from adult cattle (1/39; 2.5%) (p < 0.005). VT2+ eae- E. coli was prevalent in foods and adult cattle at slaughterhouse. The prevalence of the eae gene was similar between VTEC strains isolated from meat (0/21) and adult cattle (1/39; 2.5%) which constitutes the main population processed at slaughterhouses in Argentina. Serotyping showed that VTEC strains were distributed among 31 serotypes, some of which (O20:H19, O91:H21, O113:H21, O116:H21, O117:H7, O171:H2, OX3:H21) were shared between bovine and food strains. These O serogroups have been isolated from cases of haemorrhagic colitis (HC) and haemolyticuraemic syndrome (HUS) in humans in several continental European countries. This study confirms the role of cattle as a reservoir of many VTEC serotypes other than O157:H7 and represents a base for future diagnostic, prevention and control strategies of EHEC in this country. In addition, this study affirms the advantages of PCR-based screening of E. coli isolates given the finding of so many verotoxin-producing strains.

Prevalence of bovine verotoxin-producing Escherichia coli in Argentina.

Faecal swabs obtained from 126 calves and 118 cows in Argentina were investigated for the presence of verotoxin-producing Escherichia coli (VTEC). VTEC strains were recovered from 10 (23%) of 43 calves with diarrhoea, from 24 (29%) of 83 healthy calves, from 40 (44%) of 91 healthy cows waiting at the slaughterhouse, and from 6 (22%) of 27 healthy grazing cattle. PCR showed that 21 (9%) of animals carried VT1+ strains, 49 (20%) VT2+ strains and 10 (4%) VT1+ VT2+ strains. VT1+ strains predominated among calves (16% versus 0.8%; p < 0.001). The presence of eae gene was significantly more frequent among VTEC strains isolated from calves (78%; 46/59) than from cows (2%; 1/65) (p < 0.001). Furthermore, eae gene was more prevalent in VT1+ strains (97%; 32/33) than in VT2+ strains (14%; 10/70) (p < 0.001) and in VT1+ VT2+ strains (24%; 5/21) (p < 0.001). Sorbitol negative high virulent strains serogroups O157 were not detected. This study indicates that cattle are a reservoir of VTEC strains, and that eae gene is associated with VT1+ strains that are predominating among young animals. Fortunately, only adult animals are taken to the slaughterhouse, among which VTEC strains negative for eae gene are predominating.

Differentiation of pathogenic and non-pathogenic leptospires by means of the polymerase chain reaction.

A polymerase chain reaction was carried out to detect pathogenic leptospires isolated from animals and humans in Argentina. A double set of primers (G1/G2, B64-I/B64-II), described before, were used to amplify by PCR a DNA fragment from serogroups belonging to Leptospira interrogans but did not allow to detect saprophytic strains isolated from soil and water (L. biflexa). This fact represents an advantage since it makes possible the differentiation of pathogenic from non-pathogenic leptospires in cultures. The sensitivity of this assay has been determined, allowing to detect just only 10 leptospires in the reaction tube. Those sets of primers generated either a 285 bp or 360 bp fragment, depending on the pathogenic strain.

Variabilidad anatómica de las ramas medial y lateral de la arteria cerebelar superior / Anatomical variability of the superior cerebellar artery medial and lateral branches

Existe aún poca información cuantitativa y cualitativa disponible, de las arterias que componen el sistema vértebro-basilar, entre las cuales tenemos las cerebelares, de gran importancia en la cirugía que se realiza en la fosa posterior del cráneo. Los objetivos de nuestro estudio son analizar y suplementar la información anatómica relacionada con la arteria cerebelar superior, considerando además el lado, sexo, grupo étnico e índice cefálico de los especímenes observados. La investigación se efectuó en 70 encéfalos de individuos brasileños adultos, de ambos sexos, con registros antropológicos, colectados para investigación, inyectados con látex neopreno y fijados en formaldehido al 10 por ciento, en el Laboratorio de Anatomía de la Escola Paulista de Medicina /UNIFESP, Sao Paulo, Brasil. Las mediciones cefálicas y cálculo del índice cefálico, se efectuaron de acuerdo a normas de MARTIN SALLER (1957). Los datos estadísticos fueron procesados usando los programas computacionales EPISTAT y EPI-INFO. La rama medial derecha, se originó en el segmento pontino-anterior de la arteria cerebelar superior en el 85.7 por ciento en el sexo masculino y en el 57.9 por ciento en el femenino; 73.3 por ciento en blancos y en el 88.0 por ciento en mestizos; en el 78.1 por ciento en dólico-mesocéfalos y en el 78.9 por ciento en braquicéfalos. La rama lateral derecha, se originó en el segmento ambiens en el 85.7 por ciento en ambos sexos; en el 84.5 por ciento en blancos y en el 88.0 por ciento en mestizos; en el 87.5 por ciento en los dólico-mesocéfalos y en 84.2 por ciento en los braquicéfalos. La variabilidad de los patrones arteriales es evidente cuando su usan distintos parámetros y se consideran características antropológicas de los individuos en estudio

Detection of an antigenic protein of Leptospira interrogans which shares epitopes with the equine cornea and lens.

A protein epitope which is involved in an antigenic relationship between equine ocular tissues and Leptospira interrogans was detected in homogenates of the bacterium. The antigenic determinant was harboured on a peptide structure which was shown to be sensitive to the action of denaturing and reducing agents by means of Western blotting. The outer surface of the leptospires appeared to be free of this epitope as was proved by dot-blot and electron microscopic studies.

[Effectiveness of dermatologic minor surgery in the office of the family physician and patient satisfaction in relation with ambulatory surgery]. / Efectividad de la cirugía menor dermatológica en la consulta del médico de familia y satisfacción del paciente en relación con la cirugía ambulatoria.

BACKGROUND: The minor surgery by family physicians increase the primary care competences. The purpose of this work is to prove patients' satisfaction and minor surgery effectiveness practiced by family physicians in health centers with respect to ambulatory's general surgeon. MATERIAL AND METHODS: Case-control retrospective study, comparing dermatological surgical procedures performed by 4 family physicians and 8 3rd-year Family Physician residents with surgical procedures wade made by a surgeon over one a year period. Variables analysed include: descriptive samples homogeneity, surgery effectiveness (waiting time, esthetic results, healing time and number of visits, and histopathologic correlation) and patients' satisfaction (with the waiting time, with the results of surgery and with the physician). RESULTS: Minor surgical procedures carried out by 146 family physicians and 61 general surgeons were compared, in congruence with the analyzed descriptive homogeneity's parameters. Family physicians average waiting time was the lower, with a mean of 45 days less than the surgeon. Patient's satisfaction with the physician was higher when family physician were involved (p < 0.001); the same could be applied for the waiting time (p < 0.001). There were no significant differences over the effectiveness and patients' satisfaction. CONCLUSION: The dermatologic minor surgery by family physician is effective, satisfactory for patients, and has less waiting time. This results justify the introduction of minor surgery in the family physicians office.

Distribución arterial en la fisura horizontal del cerebelo / Arterial distribution in the horizontal fissure of cerebellum

Se efectuó un estudio anatómico mesoscópico de la distribución arterial en la fisura horizontal del cerebelo, considerando el lado, sexo y otros parámetros generalmente no considerados en la literatura, como son: grupo étnico (GE) e índice cefálico-horizontal (IC). Esta investigación, se basó en la observación de 70 encéfalos de individuos brasileños, adultos, de ambos sexos provenientes del Servicio de Verificación de Obitos de la Escola Paulista de Medicina, UNIFESP, Sao Paulo, Brasil. Además, se efectuó un Registro Antropológico para cada individuo y las mediciones cefálicas fueron hechas de acuerdo a técnicas específicas, para su clasificación según el IC. Los encéfalos fueron retirados, inyectados por látex neopreno coloreado de rojo y fijados según técnicas anatómicas. En nuestras observaciones, la fisura horizontal del cerebelo, se encontraba irrigada en el 54,8 por ciento por la rama lateral (RL) de la arteria cerebelar superior (ACS) en el lado derecho, en los encéfalos de sexo masculino y en el 28,6 por ciento en el femenino; en el 48,9 por ciento en los caucásicos y en el 36.0 por ciento en los no-caucásicos; en el 50.0 por ciento en los dólico-mesocéfalos (DM) y en el 39.54 por ciento en los braquicéfalos (BH). En el lado izquierdo, la fisura horizontal cerebelar se encontraba irrigada por la RL en el 42.4 por ciento en el sexo masculino y en 57.1 por ciento en el sexo femenino; 51.1 por ciento en el grupo caucásico y en el 50.0 por ciento en los no-caucásicos; en el 50.0 por ciento en los DM y en 57.9 por ciento en los BH

Distancia desde el origen de la arteria cerebelar superior hasta la bifurcación de la arteria basilar y origen de la arteria cerebelar anterior inferior / Distance between the origin of the superior cerebellar artery to basilar artery bifurcation and anterior inferior cerebellar artery origin

En la actualidad, la literatura clínica especializada insiste en la necesidad de un conocimiento anatómico preciso, indispensable para el éxito en intervenciones neuroquirúrgicas, durante el abordaje a la fosa craneal posterior. Basados en trabajos previos, hemos realizado un estudio anatómico-menoscópico de algunas características de la arteria cerebelar superior (ACS) y de la arteria cerebelar anterior inferior (ACAI), aportando datos que contribuyen a su conocimiento, los cuales pueden ser de utilidad práctica. La investigación se realizó mediante la observación de 70 encéfalos de individuos brasileños adultos, de ambos sexos, provenientes del Servicio de Verificación de Obitos de la Escola Paulista de Medicina/UNIFESP, Sao Paulo, Brasil. Se efectuó un registro antropológico de cada indidivuo, considerando el grupo étnico (blancos o caucásicos y no-blancos o mestizos) y mediciones cefálicas según normas para su clasificación en braquicéfalos (BH) y dólico-mesocéfalos (DM). Los encéfalos fueron retirados, inyectados con látex neopreno coloreados de rojo y fijados en solución de formaldehído al 10 por ciento, de acuerdo a técnicas específicas. La disección vascular fue realizada usando microscopio quirúrgico (D. F. Vasconcelos). En el lado derecho de los encéfalos, sexo masculino, se observa, para la distancia entre el origen de las ACS y la bifurcación de la arteria basilar (AB), que el rango de 3-5 mm es el más frecuente, con el 69,0 por ciento y en el 75,0 por ciento en el sexo femenino, en el 73,3 por ciento en los blancos y en el 68,0 por ciento en los no-blancos; en el 68,4 por ciento en los BH; y en el 75,0 por ciento en los DM. En el lado izquierdo, los valores según sexo, se encuentran en el 71,4 por ciento en el masculino; y en el 64,3 por ciento, en el femenino; en el 73,3 por ciento en los blancos y en el 60,0 por ciento en los no-blancos; en el 68,4 por ciento en los BH; y en el 68,8 por ciento en los DM. La frecuencia y porcentajes que siguen corresponden al rango de 0-2 mm. Los autores insisten en la variabilidad observada en los patrones arteriales, cuando se consideran, además del lado y sexo, otros parámetros como: el grupo étnico y el índice cefálico, aquí presentados.

[Detection of enterotoxigenic Escherichia coli adhesion antigens. Study of their expression in different culture media]. / Detección de antígenos de adhesión en Escherichia coli enterotoxigénica. Estudio de la expresión en diferentes medios de cultivo.

Polyclonal antibodies were raised in rabbits against the adherence antigens K88ab, ac, ad K99 and F41 of enterotoxigenic Escherichia coli (ETEC). Their specificity for the antigen was tested by using homologous and heterologous E. coli strains, which had been grown under permissive and nonpermissive conditions for pili expression and also confronted to a purified extract of each fimbrial adhesin. Optimal conditions for agglutinating bacterial suspensions were established for both antisera and antigens. Expression of adhesins was studied in several culture media, which are being commonly used in clinical bacteriology. K99, K88ab and K88ad were satisfactorily expressed in both Minca broth and solid media on T.S.I. Mac Conkey and E.M.B. K88ac was not expressed on G1253 strain when grown on T.S.I. or in Mac Conkey when the inoculum was obtained from E.M.B. However, Mac Conkey allowed K88ac expression when inoculum had been grown on Luria-Bertani. On the other hand, F41 was only satisfactorily expressed in Minca broth, failing in being detected by agglutination in the remaining culture media. These results allow to use alternative media, beyond the recommended Minca broth, to detect adhesins K99, K88ab, and K88ad on ETEC isolates.

Detección de antígenos de adhesión en Escherichia coli enterotoxigénica. Estudio de la expresión en diferentes medios de cultivo. / [Detection of enterotoxigenic Escherichia coli adhesion antigens. Study of their expression in different culture media]

Polyclonal antibodies were raised in rabbits against the adherence antigens K88ab, ac, ad K99 and F41 of enterotoxigenic Escherichia coli (ETEC). Their specificity for the antigen was tested by using homologous and heterologous E. coli strains, which had been grown under permissive and nonpermissive conditions for pili expression and also confronted to a purified extract of each fimbrial adhesin. Optimal conditions for agglutinating bacterial suspensions were established for both antisera and antigens. Expression of adhesins was studied in several culture media, which are being commonly used in clinical bacteriology. K99, K88ab and K88ad were satisfactorily expressed in both Minca broth and solid media on T.S.I. Mac Conkey and E.M.B. K88ac was not expressed on G1253 strain when grown on T.S.I. or in Mac Conkey when the inoculum was obtained from E.M.B. However, Mac Conkey allowed K88ac expression when inoculum had been grown on Luria-Bertani. On the other hand, F41 was only satisfactorily expressed in Minca broth, failing in being detected by agglutination in the remaining culture media. These results allow to use alternative media, beyond the recommended Minca broth, to detect adhesins K99, K88ab, and K88ad on ETEC isolates.

Detección de antígenos de adhesión en Escherichia coli enterotoxigénica. Estudio de la expresión en diferentes medios de cultivo / [Detection of enterotoxigenic Escherichia coli adhesion antigens. Study of their expression in different culture media]

Polyclonal antibodies were raised in rabbits against the adherence antigens K88ab, ac, ad K99 and F41 of enterotoxigenic Escherichia coli (ETEC). Their specificity for the antigen was tested by using homologous and heterologous E. coli strains, which had been grown under permissive and nonpermissive conditions for pili expression and also confronted to a purified extract of each fimbrial adhesin. Optimal conditions for agglutinating bacterial suspensions were established for both antisera and antigens. Expression of adhesins was studied in several culture media, which are being commonly used in clinical bacteriology. K99, K88ab and K88ad were satisfactorily expressed in both Minca broth and solid media on T.S.I. Mac Conkey and E.M.B. K88ac was not expressed on G1253 strain when grown on T.S.I. or in Mac Conkey when the inoculum was obtained from E.M.B. However, Mac Conkey allowed K88ac expression when inoculum had been grown on Luria-Bertani. On the other hand, F41 was only satisfactorily expressed in Minca broth, failing in being detected by agglutination in the remaining culture media. These results allow to use alternative media, beyond the recommended Minca broth, to detect adhesins K99, K88ab, and K88ad on ETEC isolates.