Acquisition of trimethoprim resistance in epidemic strain of Shigella dysenteriae type 1 from Zaire.
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Biomedical subjects
Publications and source records attributed to B Rowe.
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Four hundred and fifty-eight enterotoxigenic strains of Escherichia coli (ETEC) were examined for the presence of colonisation factor antigens (CFA) I and II, and the putative colonisation factor, E8775, using an immunodiffusion technique with specific antisera. The ETEC strains had been isolated in Thailand, Bangladesh and from travellers returning to Japan from abroad. Approximately 14% of the ETEC strains possessed CFA/I and a further 13% of the strains possessed CFA/II. The E8775 antigen was found on 5% of the strains. CFA/I was found on strains of the serogroups 04, 015, 063, 078, 090, 0110, 0126, 0128, 0153, and 0? CFA/II was found on strains of the serogroups 06, 08, 09, 078, 0115, 0139, 0? and 0 rough. The E8775 antigen was found on strains of the serogroups 025, 0115, and 0167. The results of this study emphasise the need to continue the search for other mechanisms of adhesion used by ETEC strains, and in particular strains of the serogroups 027, 034, 0148 and 0166.
Hospital outbreaks of severe gastroenteritis caused by multi-resistant Salmonella typhimurium have occurred in a number of cities throughout India since 1977. The strains involved belong to phage types 66 or 122, or are untypable; the latter are derived from types 66 or 122 by acquisition of one or more of a number of temperate bacteriophages. Types 66 and 122 are closely related and react with the same phages of the S. typhimurium typing scheme. A plasmid belonging to compatibility group F1me encoding resistance to ampicillin, chloramphenicol, kanamycin, streptomycin, sulphonamides, spectinomycin, tetracyclines, gentamicin and trimethoprim (R-type ACKSSuSpTGTm) is present in all of the multi-resistant strains. Several other plasmids have been identified including an SSu resistance determinant, a group I2 transfer factor and an R factor coding for resistance to kanamycin, streptomycin and sulphonamides which is compatible with plasmids of all the standard compatibility groups. These plasmids are only present in a proportion of the strains examined. Examination of strains from other sources has identified a paediatric hospital outbreak in Saudi Arabia and a number of sporadic infections in Great Britain which have been caused by the same organisms. These studies show that, despite differences in phage type and plasmid content, this group of strains belongs to a single clone which has become widespread in India with some extension to other countries.
Of 120 specimens of garden fertilizers of animal origin purchased in retail shops, 40 (33.3%) were found to be contaminated with salmonella organisms. Untreated bone meal (53.1%) was the most heavily contaminated but 25% of specimens of this product classed as heat-treated or sterilized were positive. In all, 32 serotypes were identified.
An enterotoxigenic strain of Escherichia coli O25:H42 (strain E8775), isolated from a patient in Bangladesh with diarrhea, caused mannose-resistant hemagglutination (MRHA) of human and bovine erythrocytes. The strain did not show slide agglutination or immunodiffusion precipitin lines with antiserum specific for the colonization factor antigen CFA/I or CFA/II. A variant E. coli strain, E8775-B, did not cause MRHA or produce enterotoxin. Electron microscopy revealed the presence of fimbriae on the surface of strain E8775 but not strain E8775-B. When strain E8775 was grown at 22 degrees C, it became MRHA negative and fimbriae were absent. An antiserum prepared against strain E8775 was absorbed with strain E8775-B to make an antiserum specific for the fimbrial antigen. Using this absorbed antiserum, we found the fimbrial antigen in 48 of 742 enterotoxigenic E. coli strains. The 48 strains belonged to serogroups O25, O115, and O167. It is suggested by analogy to the properties of previously described colonization factors that these fimbriae may play a part in the colonization of the intestinal epithelium.
We examined 205 enterotoxigenic strains of Escherichia coli for colonization factor antigens (CFA) I and II, using an immunodiffusion technique with specific antisera. A total of 36 strains of serogroups O63, O78, O114, O128, and O153 and 1 rough strain possessed CFA/I and gave a single precipitin line; 47 strains of serogroups O6, O8, O80, and O115 possessed CFA/II. The latter strains gave a major precipitin line (component 3) when tested with specific antisera prepared against strain E1392 or PB-176 (both E. coli O6.H16; biotype A). However, all 16 strains of E. coli O6.H16 belonging to biotype A gave a second precipitin line (component 1) when tested with both antisera. When CFA/II-positive strains were tested with a specific antiserum prepared against E. coli O6.H16 strains of biotype B or C, all strains gave component 3, but 16 of 17 strains of E. coli O6.H16 belonging to biotype B, C, or F gave a second precipitin line (component 2) not given by strains of biotype A. CFA/II-positive strains of serogroups other than O6 gave only component 3 in tests with all specific antisera. Nine enterotoxigenic strains of serotypes O7, O15, O25, O115, and O128 gave mannose-resistant hemagglutination of human or calf erythrocytes but lacked CFA/I or CFA/II. Although mannose-resistant hemagglutination was common in non-enterotoxigenic strains of E. coli, none of the non-enterotoxigenic strains possessed CFA/I or CFA/II; these strains included fecal strains of serogroups O6, O8, O63, and O78, fecal strains of enteropathogenic serogroups, and strains from extraintestinal sources.
Plasmids coding for colonization factor antigen I (CFA/I) and heat-stable enterotoxin (ST) were identified in 10 strains of human enterotoxigenic Escherichia coli. The strains, which belonged to serogroups O63, O114, O128, and O153, were isolated in Bangladesh, Latin America, Spain, and South Africa. Two strains produced heat-labile enterotoxin in addition to ST. CFA/I-ST plasmids were mobilized from two O128 strains into E. coli K-12 with the R factor R1-19K-. Like the prototype CFA/I-ST plasmid NTP113, mobilized previously from an E. coli O78 strain into K-12, these two plasmids were non-autotransferring. All 10 CFA/I-ST plasmids were incompatible with NTP113 and had molecular weights ranging from 59 X 10(6) to 72 X 10(6). The molecular properties of seven of these plasmids were compared with those of six CFA/I-ST plasmids previously mobilized from O78 strains from Ethiopia, South Africa, and Bangladesh and with those of one plasmid coding for CFA/I, ST and heat-labile enterotoxin from a South African strain of serogroup O63. Digestion with the restriction endonuclease HindIII showed that several plasmids had very similar fragment patterns and two were identical. Generally, a larger proportion of HindIII fragments were of common size in digests of plasmids identified in strains from related geographical areas, regardless of serogroup. However, all except one plasmid shared five or six HindIII fragments of the same size, one of which had been shown previously to be involved in CFA/I production. There was at least 90% DNA homology between CFA/I-ST plasmids with a molecular weight of about 58 X 10(6) from O78 strains from different sources. Most of the DNA sequences of these plasmids were present in a larger CFA/I-ST plasmid (72 X 10(6) from an O128 strain. The results of genetic and molecular studies suggest that CFA/I and ST production is determined by very similar plasmids in different serogroups of human enterotoxigenic E. coli from several sources.
Ammonium sulfate-precipitated supernatants of classical enteropathogenic Escherichia coli strains were negative when investigated for enterotoxin production in rabbit ligated ileal loops, rabbit skin vascular permeability factor tests, suckling mice, and Y-1 adrenal cells. They also failed to stimulate guanylate cyclase activity in homogenates of rabbit, rat, and infant mouse intestines. Furthermore, DNA from enteropathogenic E. coli lacked sequences that encode heat-labile and heat-stable enterotoxins. These studies fail to show conventional enterotoxin synthesis by classical enteropathogenic E. coli.
The non-autotransferring plasmid NTP113 codes for production of colonization factor antigen I and heat-stable enterotoxin, NTP113, which has a molecular weight of 58 X 10(6), was digested with BamHI, EcoRI, and HindIII and combinations of these restriction endonucleases, and the products of these digestions were analyzed by agarose gel electrophoresis. The results were used to construct a partial restriction map of NTP113. Transposons coding for resistance to ampicillin, kanamycin, and tetracycline were inserted into NTP113, and we obtained a series of deletion mutants, as determined by the loss of tetracycline or kanamycin resistance from strains carrying the insertion mutants. A number of plasmid mutants obtained by insertion or deletion did not code for colonization factor antigen I, but most of these mutants still coded for heat-stable enterotoxin production. The position of the inserted transposons and of the deletions were determined on the restriction map. Two regions of NTP113 were required for the expression of colonization factor antigen I, and the two sites were separated by a length of DNA corresponding to a molecular weight of about 25 X10(6).
Shigella boydii 13 strains are separable from other Shigella and Escherichia coli strains on the basis of DNA relatedness. From this observation, it was possible to confirm the existence of aerogenic S. boydii 13 strains. DNA relatedness studies also showed that strains of E. coli and strains representing all other serotypes of Shigella, including provisional strains, belong to the same genetic species.
Ten bacterial strains are described that give biochemical reactions characteristic of the genus Shigella but do not belong to any of the established or provisional serovars. The strains ferment mannitol and are antigenically indistinguishable. They do not possess any of the group antigens of Shigella flexneri, and it is therefore proposed that they be regarded as members of a new provisional serovar of Shigella boydii. Strain E16553 is designated as the test strain for the new serovar.
A hospital-based perinatal coaching program fosters communication between first-time parents and their infants. Support provided includes learning about babies' individual differences, normal responses, bonding principles, modeling techniques, early childhood development, as well as realistic expectations of new parents.
A strain of Shigella dysenteriae type 1 resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides, and tetracyclines has caused an epidemic of shiga dysentery in northeast Zaire. Since November 1979, it has caused many deaths in an extensive area which now includes neighbouring Rwanda. The strain carries a resistance plasmid of compatibility group X, indistinguishable from the plasmid previously found in strains from Somalia. This contrasts with multiply resistant strains of Sh. dystenteriae type 1 from Central America and South-East Asia in which resistance is determined by plasmids of compatibility group B.
Two thousand three hundred and seventy strains of Shigella dysenteriae, Sh flexneri, and Sh boydii isolated in England and Wales from 1974 to 1978 were tested for resistance to 12 antimicrobial drugs. Eighty per cent of strains were resistant to one or more drugs, with sulphonamide resistance occurring most frequently. Resistance to streptomycin, tetracycline, ampicillin, and chloramphenicol increased during the period, as did the incidence of multiple resistance. Most infections due to Sh dysenteriae, Sh flexneri, and Sh boydii are acquired abroad, and the increasing incidence of drug resistance among these organisms contrasts with the decreasing incidence of resistance among the indigenous Sh sonnei. These findings may indicate the need for better control of antibiotic use, particularly in developing countries.
Samples derived from farm livestock, an abattoir and a bone factory, were examined for salmonella. Twenty-seven serotypes were detected in 130 infected samples. A bone factory product was heavily infected. Salmonellosis is considered to be an important disease of dromedary calves and poultry in Ethiopia.
An antigenic scheme for Citrobacter koseri was described previously and consisted of 14 'O' antigens. Three additional antigens are now added to the scheme and type strains for these antigens are designated. Their origins and their biochemical and serological reactions are described.