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M Blanco

Publications and source records attributed to M Blanco.

At least 181 records · Page 10Linked to original sources
PubMed1993

Toxic and adhesive properties of Escherichia coli strains belonging to classic enteropathogenic serogroups.

Twenty-three strains belonging to classic enteropathogenic Escherichia coli (EPEC) serogroups were investigated for the production of heat-labile (LT) and heat-stable (STa) enterotoxins, verotoxins (VT), cytotoxic necrotizing factors CNF1 and CNF2, alpha-haemolysin (Hly), necrosis and modification of permeability in rabbit skin, lethal activity to mice, mannose-resistant (MRHA) and mannose-sensitive (MSHA) haemagglutination, relative cell surface hydrophobicity and the expression of P fimbriae. Of 23 EPEC strains, 7 (30%) belonging to serotypes O18ac: H7 (Hly+), O20: H26 (lethal), O26: H- (Hly+), O44: H18 (Hly+), O55: H- (CNF2+, necrotic and lethal), O119: H27 (VT+ and Hly+) and O142: H6 (lethal) produced toxic factors. Seven (30%) of 23 EPEC strains were MRHA+, 17 (74%) were MSHA+ and only 2 possessed high hydrophobicity. Two strains belonging to serotypes O18ac: H7 and O44: H18 that showed MRHA type IVa were fimbriated when grown on CFA medium.

Animals↗
PubMed1993

[Toxic properties of enteroinvasive Escherichia coli].

Up to now enteroinvasive Escherichia coli (EIEC) has not been extensively studied for toxin production. We have investigated 15 EIEC strains belonging to ten representative serotypes (O28ac:H-, 029:H-, O112ac:H-, O124:H-, O136:H-, O143:H-, O144:H-, O152:H-, O164:H- and O167:H-) for their ability to produce enterotoxins (LT and STa), Shiga-like toxins (SLT-I and SLT-II), cytotoxic necrotizing factors (CNF1 and CNF2) and other toxic products with necrotic or lethal activity. None of these strains were toxigenic.

Animals↗
PubMed1993

Enterotoxigenic, verotoxigenic, and necrotoxigenic Escherichia coli isolated from cattle in Spain.

To assess the role of enterotoxigenic (ETEC), verotoxigenic (VTEC), and necrotoxigenic (NTEC) Escherichia coli in cattle with diarrhea, 1,524 colonies of E coli isolated from 197 calves with diarrhea and from 112 healthy controls were investigated for production of heat-labile and heat-stable enterotoxins, verotoxins, and cytotoxic necrotizing factors (CNF1 and CNF2). The ETEC were isolated from only 2 (1%) calves with diarrhea and from 5 (4%) healthy controls. In contrast, VTEC and NTEC that produced CNF2 were frequently identified. The VTEC were isolated from 18 (9%) calves with diarrhea and from 21 (19%) healthy cattle (P < 0.05), whereas NTEC that produced CNF2 were detected in 39 (20%) ill calves and in 38 (34%) controls (P < 0.01). Therefore, VTEC and NTEC that produced CNF2 were isolated significantly more frequently from healthy than diseased calves. Serogroups to which VTEC belonged differed considerably from the O groups involved with NTEC. Although, VTEC belonged to 18 serogroups, only 4 (O26, O103, O113, and O157) accounted for 56% (25 of 45) of verotoxigenic strains. The NTEC that produced CNF2 belonged to 26 serogroups; however, 64% (69 of 108) were from 6 serogroups (O1, O3, O15, O55, O88, and O123). Our results are compatible with cattle being a reservoir of VTEC that are pathogenic for human beings and with ETEC being an unusual cause of bovine colibacillosis in Galicia (northwestern Spain). Furthermore, results of this study indicate that VTEC and NTEC that produced CNF2 may be part of the normal intestinal flora of cattle.

Animals↗
PubMed1992

Establishment of three categories of P-fimbriated Escherichia coli strains that show different toxic phenotypes and belong to particular O serogroups.

Eight hundred and nineteen strains of Escherichia coli isolated in Spain between 1986 and 1991 from extraintestinal infections and feces of healthy controls were investigated for expression of P-fimbriae using a particle agglutination test. Among strains causing urinary tract infections, sepsis and other extraintestinal infections, P-fimbriae were found in 31% (130/420) (P < 0.001), 25% (30/118) (P < 0.001) and 12% (11/92) (P < 0.5) respectively. In contrast, only 7% (14/189) of faecal isolates from healthy individuals carried P-fimbriae. According to two more common toxic markers detected in this study (alpha-haemolysin and cytotoxic necrotizing factor type 1), P-fimbriated E. coli strains were grouped into three categories: haemolysin+cytotoxic necrosing factor+ (Hly+CNF1+) (68/185; 37%), haemolysin+cytotoxic necrosing factor- (Hly+CNF1-) (61/185; 33%) and Hly-CNF1- (56/185; 30%). The 185 P-fimbriated strains belonged to 17 different O serogroups. However, 148 (80%) were of one of six serogroups (O1, O2, O4, O6, O7 and O18). The most frequent serogroups determined in the Hly+CNF1+ strains were the O4 and O6 (53/68; 78%), in the Hly+CNF1- strains it was the O18 (27/61; 44%) and in the Hly-CNF1- strains the O1, O2 and O7 (41/56; 73%). The majority (160/185; 86%) of P-fimbriated E. coli expressed the mannose-resistant haemagglutinin type IVa.

Bacterial Toxins↗
PubMed1992

Tracheoesophageal fistula, gastrointestinal abnormalities, hypospadias, and prenatal growth deficiency.

We studied 2 sibs, born to consanguineous parents, who presented with an MCA pattern which includes low birthweight, tracheoesophageal fistula, duodenal atresia, extrahepatic biliary atresia, hypoplastic pancreas, and hypospadias. This constellation of congenital anomalies appears to be a previously unreported autosomal recessive syndrome. A computerized search of the data files of the Spanish Collaborative Study of Congenital Malformations (ECEMC) identified 3 other unrelated infants with intestinal atresias, hypospadias, and low birth weight. These cases may represent a milder expression of the same syndrome.

Abnormalities, Multiple↗
PubMed1992

Serogroups of Escherichia coli strains producing cytotoxic necrotizing factors CNF1 and CNF2.

The serogroups of 396 necrotizing Escherichia coli of human and bovine origin isolated in Spain between 1979 and 1991 have been determined. The 270 cytotoxic necrotizing factor strains belonged to 22 different O serogroups; however, 84% (226 of 270) were of one of seven serogroups (O2, O4, O6, O14, O22, O75 and O83). Although necrotizing E. coli producing cytotoxic necrotizing factor 2 belonged to 28 different serogroups, only six of them (O1, O3, O15, O55, O88 and O123) accounted for 60% (76 of 126) of cytotoxic necrotizing factor 2 strains. Furthermore, only 3% (4 of 126) of cytotoxic necrotizing factor 2 strains belonged to serogroups most common among strains producing cytotoxic necrotizing factor 1. The majority of necrotizing E. coli producing cytotoxic necrotizing factor 1 were obtained from human extraintestinal infections, whereas cytotoxic necrotizing factor 2 strains were isolated from stools of healthy and diarrhoeic calves.

Animals↗
PubMed1992

Bovine Escherichia coli of serotypes O55:H4 and O55:H21 which produce CNF2 express P fimbriae and Vir surface antigen, respectively.

We have characterized the toxic and adhesive properties of Escherichia coli strains producing the second type of cytotoxic necrotizing factor (CNF2) and belonging to the classic enteropathogenic serogroup O55. Bovine CNF2 strains of serotype O55:H4 express P fimbriae as do pyelonephritic Escherichia coli that cause infections in humans. In contrast, strains of serotype O55:H21 which produce CNF2 from bovine origin possess the Vir surface antigen. One human strain of serotype O55:H- was positive for production of CNF2, but was negative for the two adhesive factors and for mannose-resistant haemagglutination.

Animals↗
PubMed1992

Enterotoxigenic and necrotizing Escherichia coli in human diarrhoea in Spain.

Enterotoxigenic Escherichia coli (ETEC) strains of serotype 0153: K-:H45 CFA/I+ STa+ were associated with two outbreaks of neonatal diarrhoea that occurred in two different hospitals of Madrid, in one of which several children died. Two other outbreaks were associated with ETEC strains of serotypes 0159: K-:H21 (LT+) and 0159: K-:H4 (LT+ STa+) without CFA/I and CFA/II colonization factors. Necrotizing E. coli (NTEC) strains of serotype 06:K13, producing the cytotoxic necrotizing factor CNF1 and alpha-haemolysin, were also associated with two outbreaks of neonatal diarrhoea that occurred in a hospital in Madrid and in a hospital in Talavera de la Reina. The results of the characterization of some ETEC and NTEC strains isolated from sporadic cases of diarrhoea are also discussed.

Adult↗
PubMed1992

Carbohydrate and protein histochemistry during oogenesis in Halobatrachus didactylus (Schneider, 1801) from the Bay of Cadiz (Spain).

Histological and histochemical characteristics were studied in Halobatrachus didactylus (Schneider, 1801) during oogenesis. Three phases could be differentiated: previtellogenesis (oogonia and basophilic oocytes), vitellogenesis (yolk synthesis) and maturation-spawning. Glycogen, glycoproteins and proteins rich in certain amino acids were present in the previtellogenic as well as in the vitellogenic cytoplasm oocytes. No acid mucosubstances were detected. Three types of yolk (vesicles, vacuoles and granules) contained different types of organic reserves; granules were essentially proteic whereas globules were lipidic. Carbohydrates and proteins were present in vesicles.

Animals↗
PubMed1992

A microbiological, histopathological and immunohistological study of the intragastric inoculation of Listeria monocytogenes in mice.

The course of murine infection after intragastric inoculation of L. monocytogenes was investigated by immunocytochemical, histopathological and microbiological techniques. L. monocytogenes antigen was observed in epithelial cells of intestinal mucosa overlying Peyer's patches, but not in mucosa devoid of them. This suggests that penetration of L. monocytogenes into the host organism may take place through epithelium overlying Peyer's patches. The efficiency of bacterial penetration appeared to be low, as shown by the small amounts of L. monocytogenes antigen detected and the low counts of bacteria in organs. Gross or histopathological lesions in the intestinal tract were not observed. The presence of L. monocytogenes in spleen, liver and in maxillary and mesenteric lymph nodes, confirmed that the systemic course of infection by this route of inoculation is similar to that of the parenteral routes. The results emphasize the subclinical character of murine listeriosis by the oral route.

Administration, Oral↗
PubMed1992

Absorption of Intralipid and interferences from nutrients infused into the peritoneal cavity of the rat.

We studied the peritoneal absorption and elimination of Intralipid after its intraperitoneal and intravenous infusion into rats, by means of a two-compartment model. Follow-up measurements of the plasma triglyceride rate were made. The peritoneal absorption of Intralipid gives the following absorption and elimination constants: Ka (absorption constant from the peritoneal cavity) is 0.106 +/- 0.08 h-1; Ke (elimination constant from the blood stream) is 0.0440 +/- 08 h-1; and BAa (absolute bioavailability) is 84.5 +/- 0.08% 8 hours after infusion. These results show that the intraperitoneal absorption of Intralipid is high and progressive during the first 8 hours, thus supplying the daily caloric needs of the animal through the administration of a single bolus administration, and the plasma triglyceride clearance is faster than the intraperitoneal absorption after the first 6 hours, thus avoiding dangerous overloads. We also studied the behavior of different combinations of glucose, amino acids, and fats infused into the peritoneal cavity of rats in order to observe possible interferences with the absorption of these nutrients. Two microcuries of radioactive L-glucose-1-C14 with 5 mL of 5% D-glucose, with 5 mL of 3.5% amino-acid solution, or with 5 mL of 20% fat emulsion were infused intraperitoneally into three different groups of animals. Slight differences of plasma radioactivity were registered among these three groups 1 hour after infusion. Likewise, small differences of plasma radioactivity were observed between the animals receiving an infusion of 1 microCi of five L-amino-acids-U-C14 diluted with 5 mL of 3.5% amino-acid solution, with 5 mL of 5% glucose solution, or with 5 mL of 20% fat emulsion 4 and 6 hours after infusion. No differences in the plasma triglyceride rates were observed between those groups of animals infused with 5 mL of 20% Intralipid plus 5 mL of glucose solution or with 20% Intralipid plus 3.5% amino-acid solution compared with the group receiving only 5 mL of 20% Intralipid. The infusion of fats does not seem to interfere with that of other substrates, possibly because of the different absorption route (lymphatic for fats and capillary vessels for amino acids and glucose solutions), but further research is needed to reach conclusive results. Perhaps the prolonged administration of fat, together with other substrates, produces precipitates and other galenic problems that hinder absorptive mechanisms of the preparations.

Absorption↗
PubMed1992

A direct plating method for monitoring the contamination of Listeria monocytogenes in silage.

Twenty-two silage samples were analyzed for the presence of L. monocytogenes using five Listeria selective plating media, with and without previous selective enrichment step. L. monocytogenes was recovered from 3 samples by both procedures, but direct plating allowed the quantification of Listeria population. Two of these positive samples were implicated in outbreaks of listeriosis in sheep; the L. monocytogenes population in these samples was about 10(6) cells/g. The L. monocytogenes population in the other positive sample was 10(3) cells/g. Direct isolation of L. monocytogenes was only possible from LPM, PALCAM and LSAMm media. MOX and LSM media were not selective enough to allow direct Listeria isolation. In our hands, LSAMm was the most suitable plating medium for the direct isolation and specific quantification of L. monocytogenes from silage employing a red blood cells overlay technique.

Animals↗
PubMed1992

Role of potassium tellurite and brain heart infusion in expression of the hemolytic phenotype of Listeria spp. on agar plates.

The influence of potassium tellurite (PT) and brain heart infusion agar (Difco), two components of modified Listeria selective agar medium (LSAMm), on the hemolytic phenotype of Listeria spp. was studied. L. monocytogenes and L. ivanovii displayed bigger zones of hemolysis on brain heart intusion agar compared with on Columbia agar base. The addition of PT increased the sizes of zones of hemolysis displayed by L. monocytogenes. This effect seemed to be produced by the enhancement of the cytolytic effect of listeriolysin O. PT decreased the hemolysis produced by L. ivanovii, and this effect seemed to be due to an inhibition of the sphingomyelinase C produced by this species.

Culture Media↗
PubMed1992

Epidemiologic investigation of a silage-associated epizootic of ovine listeric encephalitis, using a new Listeria-selective enumeration medium and phage typing.

The role of silage feeding in the origin of an epizootic of encephalitic listeriosis in a sheep flock was investigated by use of a new direct Listeria-selective isolation and enumeration medium, in combination with serotyping and phage typing. The silage contained high numbers (about 10(6) cells/g) of a L monocytogenes strain indistinguishable with respect to serovar and phagovar from that isolated from the brains of sick sheep. These results provided unambiguous bacteriologic evidence of the epidemiologic link between silage consumption and listeriosis in ruminants.

Animals↗
PubMed1991

Temporal distribution of human rotavirus serotypes 1,2,3, and 4 in Venezuelan children with gastroenteritis during 1979-1989.

The temporal distribution and clinical severity of rotavirus VP7 serotypes 1, 2, 3, and 4 recovered from 427 Venezuelan children with acute gastroenteritis over a period of 11 years were studied. Rotavirus VP7 serotype was established by ELISA serotyping in 298 (69.78%) of the specimens while the serotype of the remaining 129 (30.21%) samples could not be determined. Of the specimens typed, 85 (19.90% of the total) were serotype 1, 43 (10.07%) were serotype 2, 105 (24.59%) were serotype 3, and 65 (15.22%) were serotype 4. Yearly changes in the frequency of individual serotypes were observed. The predominance of a single serotype with minor contribution from others was noted every year. In this study, serotype 1 appears to induce a less severe illness in comparison with serotypes 2, 3, and 4. No apparent association between the proportion of each serotype and the children's age were found.

Antigens, Viral↗
PubMed1991

Influence of recA mutations on gyrA dependent quinolone resistance.

We examined, in Escherichia coli, the influence of recA mutant alleles on the level of quinolone resistance promoted by mutations in the gyrA gene. We found that the recA142 mutation, abolishing all the activities of RecA protein, greatly reduced the level of resistance to the quinolone ciprofloxacin, whereas the recA430 allele affecting the SOS inducing ability of RecA, reduced ciprofloxacin resistance to a lesser extent. The recA142 mutation did not cause enhancement of ciprofloxacin induced DNA breakage in gyrA mutants, indicating that the stabilization of DNA-gyrase complexes by the quinolone is not influenced by a RecA mutant protein. We suggest that RecA protein plays a role in the repair of quinolone damage, principally through a recombinational mechanism and, to a lesser degree, through the induction of the SOS response.

DNA Repair↗
PubMed1991

Biotypes, antibiotic resistance and plasmids coding for CFA/I and STa in enterotoxigenic Escherichia coli strains of serotype O153:H45 isolated in Spain.

Enterotoxigenic Escherichia coli (ETEC) strains of serotype O153:H45 have been found recently to be a frequent cause of sporadic cases and outbreaks of neonatal diarrhoea in Spain and the most important cause of infant diarrhoea in Chile. Relationships between sugar fermentation patterns, resistance to antibiotics and plasmid profiles were analysed in nine E. coli O153:H45 strains isolated in Spain that synthesised CFA/I antigen and STa enterotoxin. Derivative strains obtained by curing with acridine orange, and transconjugants rendered antibiotic resistant, were characterised phenotypically and analysed for plasmid content. Two fermentation patterns were recognised: rhamnose fermenters (four strains) and rhamnose non-fermenters (five strains). The ability to ferment rhamnose was the only differential characteristic found among 49 carbohydrate fermentation tests used to establish fermentation patterns. All nine strains possessed similar plasmid profiles of three or four plasmids of 52-87 Mda. A non-conjugative large plasmid of 82 Mda or 87 Mda, depending upon the strain, was identified as that responsible for production of both CFA/I and STa. Resistance to antibiotics was determined by plasmids other than those coding for CFA/I and STa. Two conjugative resistance factors were identified: a 52-Mda plasmid coding for resistance to ampicillin, streptomycin and sulphonamide in rhamnose-fermenting strains, and a 77-Mda plasmid coding for resistance to ampicillin, streptomycin, kanamycin, tetracycline and sulphonamide in rhamnose non-fermenting strains. Our results support the hypothesis that the prevalence and distribution of ETEC strains belonging to serotype O153:H45 in Spain and Chile could be due to the extensive cultural relations between Spain and South American from the past.

Anti-Bacterial Agents↗