PubMed Health⌕ Search

Biomedical subjects

B Rowe

Publications and source records attributed to B Rowe.

At least 289 records · Page 16Linked to original sources
PubMed1985

Identification by DNA hybridization of enterotoxigenic Escherichia coli in a longitudinal study of villages in Thailand.

Radioactively labeled enterotoxin genes were used to study the epidemiology of enterotoxigenic Escherichia coli infections in two Thai villages. When E. coli that were isolated from 674 specimens were fixed on nitrocellulose paper and examined for hybridization with E. coli enterotoxin gene probes in Bangkok, the technique had a sensitivity of 94% (31 of 33) and a specificity of 100% (641 of 641), when compared with tests of E. coli for enterotoxin production in the Y-1-adrenal cell and suckling-mouse assays. However, when the same specimens were fixed directly onto nitrocellulose paper at a field laboratory and transported to the reference laboratory for assay with the gene probes, 27 specimens that contained enterotoxigenic E. coli did not hybridize with the E. coli gene probes. Enterotoxigenic E. coli that hybridized with the LT, ST-H, and ST-P probes were identified in 10% (17 of 177) of villagers with diarrhea, 7% (8 of 108) of contacts of individuals with diarrhea caused by enterotoxigenic E. coli, and 3% (32 of 1,199) of persons not associated with cases of diarrhea caused by enterotoxigenic E. coli. Enterotoxigenic E. coli that hybridized with the ST-II probe was not a cause of diarrhea. Alternative methods of retaining DNA on filters under field conditions are needed before this technique can be used for direct examination of specimens with enterotoxin gene probes.

Adolescent↗
PubMed1985

Enzyme-linked immunosorbent assays for the detection of adhesion factor antigens of enterotoxigenic Escherichia coli.

Two hundred forty-four specimens of Escherichia coli isolated in Bangladesh and Thailand and identified as enterotoxin producers were tested for the presence of adhesion antigens by mannose-resistant hemagglutination, immunodiffusion, and enzyme-linked immunosorbent assays (ELISAs). Specific antisera to the antigens colonization factor antigen (CFA)/I, CFA/II (consisting of coli surface antigens [CS] 1, 2, and 3), and putative colonization factor antigen (PCF) 8775 (consisting of CS4, 5, and 6) were used in immunodiffusion tests and ELISAs. The results showed that the antigens could be detected in more strains by ELISA than by immunodiffusion. Twenty-nine percent of specimens of E. coli from Thailand and 47% from Bangladesh carried an adhesion antigen. Many of the strains had lost the ability to produce enterotoxins. Forty percent of strains from Thailand and 64% from Bangladesh that were still enterotoxigenic carried adhesion factors. These antigens were found on strains with heat-stable or heat-stable and heat-labile enterotoxin but not on strains producing only heat-labile enterotoxin. PCF8775 antigens were associated mainly with strains from Bangladesh, where 10 strains that produced only CS6 were detected.

Adolescent↗
PubMed1985

Cloning of genes determining the production of vero cytotoxin by Escherichia coli.

Sequences encoding the production of a cytotoxin (VT) active on Vero cells were cloned in Escherichia coli K12 from a VT-determining phage that originated in E. coli strain H19 of serotype O26.H11. Subcloning resulted in the identification of a 2.5 kb fragment that still coded for VT production. Mutagenesis with transposon Tn1000 was used to map VT sequences and a 0.75 kb probe was developed. In colony hybridization tests with strains isolated from patients with haemolytic uraemic syndrome or diarrhoea, this probe derived from the H19 VT genes detected only some of the VT+ strains belonging to serogroup 0157. A VT+ strain, E32511, serotype 0157.H-, which was negative in colony hybridization was the source of another VT-determining phage from which VT sequences were cloned. Southern hybridization of the VT genes from E32511 with the H19 probe was negative under stringent conditions but there was weak homology under conditions of low stringency. These results indicate that there are differences in the VT genes of pathogenic E. coli.

Bacterial Toxins↗
PubMed1985

The possession of three novel coli surface antigens by enterotoxigenic Escherichia coli strains positive for the putative colonization factor PCF8775.

A possible colonization factor, E8775, has previously been described for enterotoxigenic Escherichia coli strains of serogroups O25, O115 and O167. Re-examination of these strains by immunodiffusion has revealed that the antigenic nature of this factor, renamed putative colonization factor (PCF) 8775, is more complex than was first thought. All the strains of serogroup O25 tested possessed two antigenic components, termed CS4 and CS6, and gave mannose-resistant haemagglutination (MRHA) of human and bovine erythrocytes. Spontaneous variants possessing CS6 only did not give MRHA. Strains of serogroups O115 and O167 had the antigenic components CS5 and CS6, and gave MRHA of human, bovine and guinea-pig erythrocytes. Using immune electron microscopy, the components CS4 and CS5 were identified as fimbriae. No fimbriae were associated with CS6.

Antigens, Bacterial↗
PubMed1985

Properties of wild-type strains of enterotoxigenic Escherichia coli which produce colonization factor antigen II, and belong to serogroups other than O6.

Enterotoxigenic strains of Escherichia coli, which belonged to serogroups other than O6 and produced colonization factor antigen II, usually produced only coli surface antigen 3 (CS3) and gave weak mannose-resistant haemagglutination of bovine erythrocytes. A non-autotransferring plasmid, NTP165, from a strain of E. coli O168. H16 coded for heat-stable enterotoxin, heat-labile enterotoxin and CS antigens. The CS antigens expressed after acquisition of plasmid NTP165 depended on the recipient strain: a biotype A strain of serotype O6. H16 expressed CS1 and CS3; a biotype C strain of serotype O6. H16 expressed CS2 and CS3; strain K12 and strain E19446 of serotype O139. H28 expressed only CS3. An exceptional wild-type strain, E24377, of serotype O139. H28 produced CS1 and CS3 when isolated; a variant of E24377 which had lost the plasmid coding for CS antigens produced both CS1 and CS3 after the introduction of NTP165.

Antigens, Bacterial↗
PubMed1985

Escherichia coli contains plasmids coding for heat-stable b, other enterotoxins, and antibiotic resistance.

Plasmid DNAs obtained from 18 Escherichia coli isolates that hybridized with the heat-stable b (ST-b) enterotoxin gene probe were examined by Southern blot analysis for genes coding for heat-labile, ST-a, and ST-b enterotoxins with specific radiolabeled DNA probes. Four E. coli isolates contained plasmids coding for both heat-labile and ST-b enterotoxins, and one isolate contained a plasmid coding for ST-a and ST-b. Five of 11 isolates of antibiotic-resistant enterotoxigenic E. coli isolates containing ST-b-coding DNA transferred a plasmid coding for both antibiotic resistance and ST-b to E. coli K-12, suggesting that the widespread use of antibiotics could increase the distribution of genes coding for ST-b.

Anti-Bacterial Agents↗
PubMed1985

Enterotoxigenic Escherichia coli strains belonging to a new serogroup, Escherichia coli O166.

Thirty-two strains of Escherichia coli belonging to a new O group, O166, were examined. Twenty-one strains had the flagella antigen H27, five had the H15 antigen, five had the H7 antigen, and one was nonmotile. All the H27 strains and the nonmotile strain produced heat-stable enterotoxin but not heat-labile enterotoxin. All the H7 strains produced heat-labile enterotoxin but not heat-stable enterotoxin. The remaining strains were nonenterotoxigenic. None of the strains possessed colonization factor antigens CFA/I, CFA/II, or PCF8775.

Adhesiveness↗
PubMed1984

Drug resistance in Shigella dysenteriae, S flexneri and S boydii in England and Wales: increasing incidence of resistance to trimethoprim.

A total of 2753 strains of shigella belonging to subgroups A, B, and C that were isolated from patients in England and Wales during the period from 1979 to mid-1983 were studied. Of these, 1690 (61%) were from patients recently returned from abroad or in contact with recent travellers, and 760 (45%) of these affected travellers from the Indian subcontinent. The number of strains resistant to sulphonamides and streptomycin remained at a high level throughout (average 76% and 72% respectively). Resistance to tetracyclines, ampicillin, and chloramphenicol rose, reaching 63%, 51%, and 48%, respectively, in 1982. Strains resistant to trimethoprim were seen in substantial numbers for the first time and increased from 1.3% of all strains in 1979 to 9.9% in 1982 and 16.8% in the first half of 1983. The proportion of patients with recent foreign contact was notably smaller among those with strains resistant to trimethoprim than among those with strains sensitive to trimethoprim. The increase in resistance to trimethoprim might partly result from the use in Britain of compounds containing trimethoprim for the treatment of shigellosis.

Ampicillin↗
PubMed1984

Identification by DNA hybridisation of enterotoxigenic Escherichia coli in homes of children with diarrhoea.

The DNA hybridisation technique to detect genes coding for Escherichia coli enterotoxin was used to identify enterotoxigenic E coli (ETEC) in homes of children with diarrhoea in Thailand. ETEC was found in 30 (14%) of 221 children with diarrhoea and in 9% (8/88) of their household contacts, 8% (8/101) of their neighbours, and 2% (32/1379) of inhabitants of 382 homes not associated with ETEC infections. ETEC was found significantly more often in water and food and on mothers' hands in homes of children with ETEC-associated diarrhoea and of their neighbours than in homes of children without ETEC infections (8/360 vs 3/2290; p less than 0.001). ETEC was identified in 80% (71/89) of specimens that hybridised with the enterotoxin gene probes by testing E coli isolated from the same specimen in the Y-1 adrenal and suckling-mouse assays. The DNA hybridisation assay to detect genes coding for E coli enterotoxin is an effective method of identifying ETEC in a large number of human and environmental specimens and will be a valuable tool to define further the epidemiology of this enteric pathogen.

Child, Preschool↗
PubMed1984

The use of Moore swabs for isolation of Salmonella typhi from irrigation water in Santiago, Chile.

In Chile, a country with an exceedingly high incidence of typhoid, untreated sewage is applied directly to fields where salad vegetables are cultivated. Water used for irrigation was examined for the presence of Salmonella typhi, by making use of the sewer-swab technique. S typhi was isolated in 8 (11%) of 76 irrigation samples examined from nonindustrial, polluted water. This supports the hypothesis that crops grown with water contaminated with feces are important vehicles in the transmission of S typhi in this endemic area. Since sewage treatment plants will not be available in Santiago in the near future, emphasis is being placed on devising alternative methods of irrigation and on growing vegetables that are cooked before being eaten.

Bacteriological Techniques↗
PubMed1984

Prophylactic doxycycline for travelers' diarrhea in Thailand. Further supportive evidence of Aeromonas hydrophila as an enteric pathogen.

A randomized double-blind study to determine the efficacy of a three-week course of doxycycline (100 mg daily) in preventing travelers' diarrhea was performed in 1980 among 63 United States Peace Corps volunteers during their first five weeks in Thailand, an area where doxycycline-resistant enterotoxigenic Escherichia coli are known to be common. Eight (24%) of 33 volunteers taking placebo and 3 (10%) of 30 taking doxycycline developed travelers' diarrhea for a calculated protection of 59%, but this was not statistically significant (p = 0.12). Aeromonas hydrophila was isolated from 8 to 19 volunteers with either travelers' diarrhea or mild diarrhea in the placebo group, but from only 1 of 12 in the doxycycline group (p less than or equal to 0.05). Furthermore, doxycycline significantly prevented colonization of the gastrointestinal tract with A. hydrophila while it was being taken (p less than or equal to 0.01). Enterotoxigenic E. coli was isolated from only one volunteer with travelers' diarrhea in the placebo group and from none in the doxycycline group. Doxycycline prophylaxis of travelers' diarrhea in this geographic area, though not shown to be significantly protective, further supports the role of A. hydrophila as an enteric pathogen.

Adult↗
PubMed1984

Six new E. coli O groups: O165, O166, O167, O168, O169 and O170.

Six Escherichia coli strains are established as antigenic test strains for six new O groups, O165, O166, O167, O168, O169 and O170. They are isolates from diarrhoea but only O167 and O168 are enterotoxigenic (ETEC). The O170, O169 and O166 strains are the earlier provisional O group strains OX1, OX2 and OX8, respectively.

Antigens, Bacterial↗
PubMed1984

Colonization factors associated with enterotoxigenic Escherichia coli isolated in Thailand.

Eighty-six percent (72 of 84) of heat-labile and heat-stable, none of 141 heat-labile, and 24% (27 of 111) heat-stable enterotoxigenic Escherichia coli isolates from Thailand aggregated in less than 1 M (NH4)2SO4, hemagglutinated human group A and bovine erythrocytes in 1% D-mannose, and possessed either colonization factor I or colonization factor II. No other colonization factors were identified by these two methods.

Ammonium Sulfate↗
PubMed1984

Enzyme-linked immunosorbent assay for Escherichia coli heat-stable enterotoxin.

The sensitivity of an enzyme-linked immunosorbent assay (ELISA) to detect pure native Escherichia coli heat-stable toxin (ST) and to identify ST-producing strains among clinical isolates was determined. Two synthetically produced ST preparations were used to raise hyperimmune antisera in rabbits and goats: ST(S), which has the same antigenicity as native ST; and ST(C), which is 15-fold more immunogenic. These antisera were used in the double-sandwich technique as either crude double-species antisera or pure single-species antibody. The sensitivity of the assay was increased by using either a purer antibody preparation or the antiserum to the more potent immunogen; the assay in which pure antibody to ST(C) was used was 2,857-fold more sensitive in detecting ST than the assay in which crude antiserum to ST(S) was used. The minimum amount of ST detectable by the ST(C) ELISA was 140 pg/ml, which was an amount 285-fold smaller than that detectable by the suckling mouse assay. Among 50 human E. coli isolates examined by both the ST(C) ELISA and an ELISA for heat-labile toxin (LT), which had a sensitivity of 290 pg/ml for LT, the respective toxins were consistently identified in broth cultures of 10 LT+ and ST-, 15 LT+ and ST+, and 10 LT- and ST+ strains, and there were no false-positive responses. The ST(C) ELISA also detected ST in all of seven ST - producing E. coli strains tested of human origin, which had been shown elsewhere by DNA hybridization probes to have ST-coding genes of either human or porcine origin, and in all of three ST-producing E. coi strains tested of porcine origin. These results indicate that the sensitivity of the ST(C) ELISA is the same as that of previously described LT ELISAs. The concomitant use of both ST and LT ELISAs provides a rapid, simple, and sensitive method for identifying among clinical isolates enterotoxigenic strains of E. coli which produce either toxin.

Animals↗
PubMed1983

Investigation of outbreaks of salmonella in hospitals.

In a two year prospective survey of outbreaks of salmonella infection in hospitals in England and Wales 55 outbreaks were identified. Reports of investigation of these outbreaks were reviewed for evidence of food borne infection and cross infection. Food borne infection probably accounted for only six outbreaks, but these made up 40% of the 15 outbreaks in which there were more than five patients and staff with symptoms. Person to person transmission was the probable mode of spread in most outbreaks. It is recommended that in addition to bacteriological investigations clinical and epidemiological data should be collected to implicate food or other possible common vehicles of infection. Bacteriological screening of patients and staff who do not have symptoms may be unrewarding in the absence of epidemiological data to define groups at risk of infection.

Adolescent↗