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11.
Nationwide surveillance program to identify diarrhea-causing Escherichia coli in children in Thailand. 总被引:2,自引:1,他引:2
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R Sunthadvanich D Chiewsilp J Seriwatana R Sakazaki P Echeverria 《Journal of clinical microbiology》1990,28(3):469-472
Escherichia coli strains isolated from children with diarrhea were collected from 16 hospitals in different districts in Thailand during 1985 and 1986 and submitted to the National Reference Laboratory. Isolates were identified by serogrouping or as enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC) adhesin factor (EAF) E. coli, or Shiga-like-toxin (SLT)-producing E. coli by DNA hybridization. EPEC strains of known serogroups were isolated from 10%, ETEC strains were isolated from 6%, EAF E. coli strains were isolated from 4%, EIEC strains were isolated from less than 1%, and SLT-producing E. coli strains were isolated from none of 393 children with diarrhea. Among 278 children whose ages were recorded, the highest rate of isolation of EAF E. coli was 11% (9 of 85) from children less than 6 months old. ETEC was isolated from 5% (4 of 85) of children less than 6 months old, from 10% (12 of 118) of children 6 to 23 months old, and from 1% (1 of 75) of children greater than 23 months old. EPEC strains of known serogroups were isolated from 18% (15 of 85) of children less than 6 months old, from 11% (13 of 118) of children 6 to 23 months old, and from 9% (7 of 75) of children greater than 23 months old. E. coli strains that hybridized with the EIEC probe were isolated from three children who were 20, 36, and 48 months old. Examining E. coli for hybridization with DNA probes for virulence determinants is a practical way of conducting nationwide surveillance of diarrhea-causing E. coli. Since only 33% (13 of 39) of EPEC serogroups hybridized with the EAF probe and none hybridized with the SLT probes, identification of EPEC by serogroups analysis, followed by serotyping, should continue to be used in the identification of EPEC. 相似文献
12.
Identification of enterotoxigenic Escherichia coli isolated from swine with diarrhea in Thailand by colony hybridization, using three enterotoxin gene probes.
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The DNA colony hybridization assay was used to identify enterotoxigenic Escherichia coli among E. coli isolated from 803 swine with diarrhea at 10 farms in Thailand. Between 5 September and 8 December 1981, enterotoxigenic E. coli were identified in 40% of 58 litters of piglets under 10 days old and 17% of 29 litters between 10 and 21 days old with diarrhea at farms at four different locations in Thailand. All E. coli that hybridized with one or more of the three enterotoxin gene probes produced heat-labile or heat-stable toxin or both, as determined by testing culture supernatants in the Y1 adrenal and suckling mouse assays. The DNA colony hybridization technique is a specific method of identifying enterotoxigenic E. coli from swine and can be used to further characterize these enteric pathogens. 相似文献
13.
Molecular characterization of Vibrio cholerae O1 strains isolated during cholera outbreaks in Guinea-Bissau.
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A Dalsgaard H F Mortensen K Mlbak F Dias O Serichantalergs P Echeverria 《Journal of clinical microbiology》1996,34(5):1189-1192
In the present study, 19 strains of Vibrio cholerae O1 biotype El Tor isolated during outbreaks of cholera in Guinea-Bissau in 1987, 1994, and 1995 were characterized to investigate a possible epidemiological relationship among the isolates. On the basis of ribotyping with the restriction enzyme BglI, 5 strains isolated in 1987 showed two closely related ribotypes, while 14 strains isolated in 1994 and 1995 showed the same ribotype that was distinct from the ribotypes of strains isolated in 1987. Southern blot hybridization of BglI-digested genomic DNA with a cholera toxin probe demonstrated that the strains isolated in 1987 showed an identical cholera toxin genotype, whereas O1 strains isolated in 1994 and 1995 showed the same genotype that was distinct from the genotype of strains isolated in 1987. These results were supported by the results of antibiotic susceptibility testing, in which strains isolated in 1987 showed resistance to polymyxin B only, while each of the strains from 1994 and 1995 showed resistance to polymyxin B, trimethoprim-sulfamethoxazole, and the vibriostatic agent O/129. Although our results are based on a limited number of V. cholerae O1 strains, they suggest that the epidemic in Guinea-Bissau in 1994 and 1995 was due to the introduction of a new strain to the country. 相似文献
14.
Type II heat-labile enterotoxin-producing Escherichia coli isolated from animals and humans. 总被引:4,自引:2,他引:4
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J Seriwatana P Echeverria D N Taylor L Rasrinaul J E Brown J S Peiris C L Clayton 《Infection and immunity》1988,56(5):1158-1161
Heat-labile enterotoxin (LT)-producing Escherichia coli strains, as identified by the Y1 adrenal cell assay, were examined with a DNA probe coding for type I and type II LTs. Of 236 LT-producing E. coli isolates, 60% hybridized with LT-I, 17% hybridized with LT-II, and 23% did not hybridize with either probe and no longer produced LT as determined by the Y1 adrenal cell assay. These isolates presumably lost plasmids coding for LT-I during storage. A total of 75% of LT-producing E. coli isolates (27 of 36) from cows, 64% of LT-producing E. coli isolates (7 of 11) from buffalo, 31% of LT-producing E. coli isolates (4 of 13) from beef obtained in markets, and 2% of LT-producing E. coli isolates (3 of 168) from humans contained genes coding for LT-II. Genes coding for LT-II were not found in 50 LT-I-producing and heat-stable enterotoxin-producing E. coli isolates from 11 children with diarrhea and 44 LT-nonproducing and heat-stable enterotoxin-producing E. coli isolates from 12 other children with diarrhea. A total of 9% of LT-II-producing E. coli isolates (3 of 34) from cows and buffalo hybridized with DNA probes for genes coding for verocytotoxin 2 (VT2), and 18% (6 of 34) hybridized with a DNA probe coding for enterohemorrhagic E. coli (EHEC) adhesin fimbriae. E. coli SA-53, the original isolate in which LT-II was found, contained genes coding for VT2 and EHEC adhesin fimbriae. Five VT-producing, LT-II-producing E. coli isolates that hybridized with the EHEC probe did not contain DNA sequences coding for VT1 or VT2. LT-II-producing E. coli strains were frequently isolated from cattle and buffalo but were rarely isolated from humans. 相似文献
15.
The GAP-related domain of tuberin, the product of the TSC2 gene, is a target for missense mutations in tuberous sclerosis 总被引:5,自引:0,他引:5
Maheshwar MM; Cheadle JP; Jones AC; Myring J; Fryer AE; Harris PC; Sampson JR 《Human molecular genetics》1997,6(11):1991-1996
Tuberous sclerosis is an autosomal dominant trait in which the
dysregulation of cellular proliferation and differentiation results in the
development of hamartomatous growths in many organs. The TSC2 gene is one
of two genes determining tuberous sclerosis. Inactivating germline
mutations of TSC2 in patients with tuberous sclerosis and somatic loss of
heterozygosity at the TSC2 locus in the associated hamartomas indicate that
TSC2 functions as a tumour suppressor gene and that loss of function is
critical to expression of the tuberous sclerosis phenotype. The TSC2
product, tuberin, has a region of homology with the GTPase activating
protein rap1GAP and stimulates the GTPase activity of rap1a and rab5a in
vitro. Here we show that the region of homology between tuberin and human
rap1GAP and the murine GAP mSpa1 is more extensive than previously reported
and spans approximately 160 amino acid residues encoded within exons 34-38
of the TSC2 gene. Single strand conformation polymorphism analysis of these
exons in 173 unrelated patients with tuberous sclerosis and direct
sequencing of variant conformers together with study of additional family
members enabled characterisation of disease associated mutations in 14
cases. Missense mutations, which occurred in exons 36, 37 and 38 were
identified in eight cases, four of whom shared the same recurrent change
P1675L. Each of the five different missense mutations identified was shown
to occur de novo in at least one sporadic case of tuberous sclerosis. The
high proportion of missense mutations detected in the region of the TSC2
gene encoding the GAP-related domain supports its key role in the
regulation of cellular growth.
相似文献
16.
Glycoproteins present in human follicular fluid that inhibit the zona- binding capacity of spermatozoa 总被引:1,自引:0,他引:1
Previous studies have suggested that human follicular fluid contains
factors that reduce the zona-binding capacity of spermatozoa. The present
study provides further evidence of the existence of such factors. Using the
hemizona binding assay (HZA), we have shown that the inhibitory effect of
human follicular fluid on the zona-binding capacity of spermatozoa is
concentration-dependent, an inhibitory effect being detected when the
concentration of human follicular fluid was > or = 10%. A 1%
concentration of human follicular fluid did not possess this inhibitory
activity. Heating human follicular fluid at 56 degrees C for 30 min did not
affect its inhibitory properties; treatment with proteinase-K abolished
such inhibition. Human follicular fluid was fractionated sequentially by
concanavalin-A affinity chromatography, Mono Q ion-exchange chromatography
and Superose-12 gel filtration. The zona binding inhibitory activity
resided in the fraction which bound to the lectin and Mono Q column and
contained molecules with native molecular weights of 32 and 192 kDa. Sodium
dodecyl sulphate-polyacrylamide gel electrophoresis analysis suggested that
the 192 kDa glycoprotein was a tetramer, while the 32 kDa glycoprotein
remained as a single molecular species under denaturing conditions. We
conclude that two glycoproteins were responsible for the zona binding
inhibitory activity of human follicular fluid. The physiological role of
these factors remains unclear.
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17.
Diagnostic utility of a multiplex herpesvirus PCR assay performed with cerebrospinal fluid from human immunodeficiency virus-infected patients with neurological disorders 总被引:2,自引:0,他引:2
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Quereda C Corral I Laguna F Valencia ME Tenorio A Echeverria JE Navas E Martín-Dávila P Moreno A Moreno V Gonzalez-Lahoz JM Arribas JR Guerrero A 《Journal of clinical microbiology》2000,38(8):3061-3067
We used a multiplex nested-PCR assay for the simultaneous detection in cerebrospinal fluid (CSF) of five human herpesviruses (HVs) (cytomegalovirus [CMV], Epstein-Barr virus [EBV], varicella-zoster virus [VZV], herpes simplex virus [HSV], and human herpesvirus 6 [HHV-6]) in a clinical evaluation of human immunodeficiency virus (HIV)-infected patients with neurological disorders. This method, which has the advantages of being rapid and economical, would be of particular interest for the diagnosis of neurological syndromes caused by more than one HV. We studied 251 CSF samples from 219 patients. HV DNA was demonstrated in 93 (37%) of the CSF samples (34% of the patients). CMV was the HV most frequently detected in our patients (25%), while EBV, VZV, HSV, and HHV-6 DNAs were present in significantly fewer cases (7, 4, 3, and 1%, respectively). When results were compared with the final etiological diagnoses of the patients, the multiplex HV PCR showed high specificity for the diagnosis of CMV and VZV neurological diseases and for cerebral lymphoma (0.95, 0.97, and 0.99, respectively). The sensitivity of the assay was high for CMV disease (0.87), was low for cerebral lymphoma (0.33), and was not evaluable for VZV disease due to the small number of patients with this diagnosis. Nevertheless, detection of VZV DNA had possible diagnostic value in four of the nine cases, and EBV DNA amplification always predicted the diagnosis of cerebral lymphoma in patients with cerebral masses. Detection of HSV DNA was frequently associated with CMV amplification and fatal encephalitis. HHV-6 was not considered to have a pathogenetic role in the three cases in which it was detected. This multiplex HV PCR assay is a specific and clinically useful method for the evaluation of HIV-infected patients with neurological disorders related to HV. 相似文献
18.
K A Bettelheim J E Brown S Lolekha P Echeverria 《Journal of clinical microbiology》1990,28(2):293-295
Escherichia coli strains isolated from adults with diarrhea in Bangkok, Thailand, were examined for hybridization with DNA probes for genes that code for Shiga-like toxin (SLT)-I, SLT-II, and serogroup O157 enterhemorrhagic E. coli (EHEC) fimbriae. Seven isolates that hybridized with the SLT-I, SLT-II, and O157 EHEC fimbria probes and produced verocytotoxin (VT; group A) were isolated from two patients with diarrhea. Two strains that hybridized with only the SLT-II probe and the O157 EHEC fimbria probe and were VT+ (group B) were isolated from two patients with diarrhea, 7 strains that hybridized with only the SLT-II probe and were VT+ (group C) were isolated from two patients with diarrhea, and 26 strains that hybridized with only the O157 EHEC fimbria probe and were VT- (group D) were isolated from four patients with diarrhea. Seven strains in group A had serotypes O2:H1 (n = 1), O110:H19 (n = 1), and Ont:H8 (n = 5); 2 strains in group B were O112ab:H21 (n = 1) and O113:H21 (n = 1); 7 strains in group C were O6:H28 (n = 1), O22:H16 (n = 1), O52:H25 (n = 1), O112ab:H21 (n = 1), OR:H45 (n = 2), and OR:H11 (n = 1); and 26 strains in group D were O76:H7 (n = 18), O146:H3 (n = 2), O146:H10 (n = 1), O146:Hnt (n = 1), OR:H16 (n = 1), Ont:H2 (n = 1), Ont:H8 (n = 1) and Ont:H16 (n = 1). In Thailand, E. coli strains that hybridized with SLT-I, SLT-II, and O157 EHEC fimbria probes were of a variety of serotypes, none of which were O157:H7. 相似文献
19.
Patterns of contrast enhancement of benign and malignant hepatic neoplasms during bolus dynamic and delayed CT 总被引:7,自引:0,他引:7
Bolus dynamic and delayed computed tomographic (CT) scans of the liver were evaluated in 43 patients with 54 hepatic hemangiomas and 111 patients with primary or secondary malignant hepatic neoplasms. Twelve patterns of contrast enhancement were recognized during the bolus dynamic phase and delayed scanning. A "typical" CT pattern for hemangiomas (present in 29 of 54 hemangiomas [53.7%]) was established: (a) diminished attenuation prior to intravenous contrast medium administration (excluding lesions arising in a liver with diffuse fatty infiltration), (b) peripheral contrast enhancement during the bolus dynamic phase, and (c) complete isodense fill-in on delayed scan images. Using these criteria, we distinguished hemangiomas from malignant neoplasms in most patients. Only one of 63 (1.6%) malignant neoplasms manifested these typical CT criteria of hemangioma. There is an 86% chance that a lesion with the typical CT appearance of hemangioma is actually a hemangioma, even when found in a patient with a known nonhepatic primary neoplasm. 相似文献