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D C Old

Publications and source records attributed to D C Old.

At least 19 recordsLinked to original sources
PubMed1992

Numerical index of the discriminatory ability of biotyping and resistotyping for strains of Escherichia coli.

A discrimination index was applied to assess the value of biotyping and resistotyping, used alone or together, for the subspecific discrimination of Escherichia coli. The index was high when 599 strains from a wide variety of sources were examined by full biotyping with 10 tests. Although the discrimination achieved was lower when a sub-collection of 333 strains was examined, that finding probably indicated that many of the latter strains were of urinary origin and represented a limited number of uropathogenic clones. Combined biotyping and resistotyping provided a higher level of strain discrimination than either method used on its own. Results suggest that these typing methods may be used with confidence for the discrimination of strains of E. coli.

Bacterial Typing Techniques↗
PubMed1992

In-vitro and in-vivo characteristics of TnphoA mutant strains of Salmonella serotype Gallinarum not invasive for tissue culture cells.

Insertion mutants of a strain of Salmonella serotype Gallinarum, the cause of fowl typhoid, were produced with transposon TnphoA. Eight mutants were identified as being less invasive in cell culture than the parent strain. Neither the parent strain nor the mutants showed mannose-sensitive haemagglutination of various red blood cell species. Although two mutants gave mannose-resistant (MR) haemagglutination of red cells of different animal species these MR activities could not be correlated with other characteristics in vitro or in vivo. The mutant strains were divisible into three classes by their patterns of invasiveness and adhesiveness in vitro and by changes in membrane proteins. Strains of classes 1 and 2 had single transposon insertions, detected by Southern hybridisation, of 8.9 and 2.4 kb EcoRV-digested chromosomal-fragments, respectively, and were slightly less invasive than the parent strain. They were no less virulent for chickens by the oral route than a mutant strain shown to be as invasive in vitro as the parent strain. The class-2 mutant was also less adhesive than the other strains. The single mutant strain of class 3 which contained insertions in several chromosomal fragments, was non-invasive in Vero cells (less than log10 1.0 cfu/ml recovered compared with log10 2.88 for the parent strain) and showed reduced virulence by both oral and intramuscular routes. The mutant strains of all classes were taken up equally rapidly from the blood by the spleen. Intramuscular immunisation of chickens with the class-3 mutant strain gave complete protection against oral challenge 3 weeks later with 1000 oral LD50 doses of the virulent parent strain.

Animals↗
PubMed1992

A cost-effectiveness study of the management of intractable urinary incontinence by urinary catheterisation or incontinence pads.

STUDY OBJECTIVE: The aim was to compare the costs and effects of management of intractable urinary incontinence by urinary catheterisation or incontinence pads. DESIGN: This was a prospective, randomised study comparing catheterisation with pads, supplemented by additional data collected from patients with chronic indwelling catheters. Main outcome measures were costs of equipment, nursing time, patient preference, nursing preference, and clinical and bacteriological assessment of urinary infection. SUBJECTS: 78 intractably incontinent elderly female patients were randomly allocated to management by urinary catheter or pads and toileting. Supplementary data on equipment costs and nursing time were collected from 27 patients, of whom 22 were already catheterised at the time of the randomisation and five were catheterised by the nursing staff after the last date for entry into the randomisation. MAIN RESULTS: Of the 38 patients randomised to catheterisation, 14 refused consent so only 24 were catheterised on day 1 of the study. There was a rapid removal of catheters, especially in the first six weeks of the study and only four of the randomised catheter patients completed the full 26 weeks of the study. However, eight of the pads patients were catheterised between the 7th and 22nd week because of deteriorating general condition and all retained their catheters for the remainder of the study period. Of 35 patients who had experienced catheters and pads, 12 expressed a clear preference for catheters, 12 for pads, and 11 were undecided. Nurses were in favour of the use of pads, mainly because of concerns about urinary infection with catheters. Comparing costs for patients managed with catheters (532 patient weeks) or pads (903 patient weeks), catheter patients required less nursing time (15.4 v 29.0 h per patient per week) but equipment costs were higher (19.20-24.65 pounds v 8.79-11.35 pounds per patient per week), mainly because of the cost of catheter care (12.75 pounds per patient per week). Asymptomatic bacteriuria was prevalent in both groups but 73% of catheterised patients received treatment for clinical signs of infection compared with 40% of pads patients. Only 30% of patients who were treated had any generalised symptoms of infection. CONCLUSIONS: Use of catheters reduces nursing time but may increase weekly equipment costs depending on the cost of laundry. Despite the high dropout rate among patients randomised to catheters a minority of patients (12/35) expressed a clear preference for catheters and we believe that more patients with intractable incontinence should be given a trial of catheterisation to assess acceptability. Bacteriuria was prevalent in pads or catheter patients but no major episodes of invasive infection were noted in either group.

Aged↗
PubMed1991

The frequency of fim genes among Salmonella serovars.

Salmonella serovars were examined for the presence of fim gene sequences using specific DNA probes. All strains, regardless of their ability to express surface-associated fimbriae, retain a considerable amount of DNA homologous to the gene probes used. The phenotypically nonfimbriae FIRN and non-FIRN strains of S. typhimurium retain detectable amounts of fim gene sequences and, therefore, may not be genotypically non-fimbriate. The MS adhesin can be expressed by type 2 fimbriate bacteria when they are transformed with discrete regions of the fim gene cluster. However, this conversion to a hemagglutinating phenotype is not associated with a small region of DNA. Therefore, the inability of type 2 fimbria-producing strains of Salmonella to mediate hemagglutination does not appear to be due to a small deletion in a single fim gene.

Adhesins, Bacterial↗
PubMed1991

Reference collection of strains of the Salmonella typhimurium complex from natural populations.

A collection of 72 reference strains of the Salmonella typhimurium complex of clones recovered from a variety of hosts and environmental sources in diverse geographic locations has been established for use in studies of variation in natural populations. Included are strains of the serovars S. typhimurium, S. saintpaul, S. heidelberg, S. paratyphi B (including variety java) and S. muenchen. The strains, which have been characterized by enzyme electrophoresis for allelic variation in 24 chromosomal structural genes and represent 48 distinctive multilocus genotypes (electrophoretic types or ETs), exemplify the full range of genotypic variation in the S. typhimurium complex. Evolutionary genetic relationships among the ETs are indicated in a phylogenetic tree generated by the neighbour-joining method from a matrix of Nei's standard genetic distance.

Alleles↗
PubMed1990

Salmonellae of serotypes gallinarum and pullorum grouped by biotyping and fimbrial-gene probing.

When salmonellae of serotypes Gallinarum (50 isolates) and Pullorum (36 isolates), that produce non-adhesive (type-2) fimbriae, were tested for their reactions in biochemical tests, 81 (94%) were found to belong to three distinct biochemical groups, I-III. Interaction of HinfI-digested DNA of both Gallinarum and Pullorum with a probe of accessory genes of type-1 fimbriation in serotype Typhimurium gave one type of Southern hybridisation pattern that was readily distinguished from that of Typhimurium strains. With a probe of the Typhimurium fimbrial subunit gene, Pullorum isolates were separated into strongly and weakly probe-reactive groups which showed restriction fragment-length polymorphism; these latter groups corresponded to biochemical groups II and III, respectively.

Bacterial Typing Techniques↗
PubMed1990

Genetic population structure, clonal phylogeny, and pathogenicity of Salmonella paratyphi B.

Genetic diversity and relationships among 123 strains of Salmonella paratyphi B (serotype 1,4,[5],12:b:[1,2]) were estimated from an assessment of electrophoretically demonstrable allelic variation at 24 chromosomal enzyme gene loci. Fourteen electrophoretic types, marking clones, were distinguished, the phylogeny of the clonal lineages was reconstructed, and biotype and other phenotypic characters were mapped onto this structure. Most d-tartrate-negative strains are members of an abundant, globally distributed clone (Pb 1) that is polymorphic for many biotype characters (including d-tartrate utilization), bacteriophage type, rRNA pattern, and colicin M and phage ES18 sensitivity. This clone is largely responsible for S. paratyphi B enteric fever in humans. In contrast, d-tartrate-positive strains (formerly known as S. java) occurred in all seven of the clonal lineages identified by population genetic analysis, although most d-tartrate-positive isolates belong to only two clones (Pb 3 and Pb 4), which vary in frequency geographically. Monophasic strains represent four closely related clones forming a distinctive phylogenetic lineage. The Kauffmann hypothesis of convergence in serotype among distantly related cell lineages through recombination (via phage transduction or other means) may account for the considerable genotypic diversity among clones of S. paratyphi B. Pb 4, Pb 6, and Pb 7 are more closely allied with clones of S. typhimurium and S. saintpaul than with other clones of S. paratyphi B. Sensitivity or resistance to colicin M and phage ES18 and the electrophoretic pattern of the rRNA, which were incorporated into a recently proposed scheme for the identification of types of S. paratyphi B, individually or in combination fail to mark clones or other meaningful phylogenetic subdivisions.

Colicins↗
PubMed1989

A novel fimbrial haemagglutinin produced by a strain of Salmonella of serotype Salinatis.

A strain of Salmonella of serotype Salinatis, that produced a mannose-resistant and eluting haemagglutinin (MREHA) when cultured at 37 degrees C but not at 18 degrees C, was examined by electron microscopy after negative staining. Production of this MREHA, previously described as being non-fimbrial, was correlated with the presence of thin fimbriae which had an external diameter of 3.6 nm. The purified Salinatis thin fimbriae had an estimated Mr of 19 kDa. This fimbrial MREHA was not produced by strains of the antigenically related serotypes Duisburg and Sandiego.

Fimbriae, Bacterial↗
PubMed1989

Some strains of Escherichia coli of putative enteroadherent-aggregative serotypes produce an unusual fibrillar haemagglutinin.

Two strains of Escherichia coli that formed on unusual kind of mannose-resistant and eluting haemagglutinin (MREHA) reacting with the red blood cells of rat and mouse, when cultured at 37 degrees C but not at 18 degrees C, were examined by electron microscopy. Production of this rare rodent-positive MREHA was correlated with the presence of fine fibrillae of estimated diameter 2.5 nm that were demonstrated by negative staining and immuno-gold labelling with MREHA-specific anti-serum. These two strains belonged to serotypes 078:H- and 078:H33; thus, it would be useful to know whether enteroadherent-aggregative strains of E. coli of these and other serotypes also possess this unusual MREHA.

Animals↗
PubMed1989

Persistent and transient clones of Salmonella typhimurium of phage type 141 recognized by biotyping.

Among the 81 cultures of Salmonella typhimurium of phage type 141 examined, 72 had been isolated from Sheffield incidents in 1984-5 and 9 were Scottish isolates from 1986-7. All of these cultures from diverse sources belonged to primary biotype 31; 79 were of full biotype 31beg and 2 anaerogenic cultures were of full biotype 31begj. This is the first known occasion on which an epidemic strain of S. typhimurium of phage type/biotype 141/31beg has been implicated in outbreaks of human or animal infection in the UK. Because previous epidemic strains of S. typhimurium of phage type 141 in the UK belonged to biotypes 1f and 9f which are phylogenetically unrelated to biotype 31beg, the likely origin of this most recent epidemic S. typhimurium strain of phage type/biotype 141/31beg is discussed.

Animals↗
PubMed1989

Numerical index of the discriminatory ability of biotyping for strains of Salmonella typhimurium and Salmonella paratyphi B.

An index of discrimination was used to assess the discriminatory power of biotyping for salmonellas of selected serotypes. Three collections of phage-typed strains of Salmonella typhimurium and Salmonella paratyphi B, previously tested for biotype, were examined. The results established that the discrimination index was high when full biotyping alone was used for differentiation of strains from international series. When biotyping was combined with phage typing, the discrimination achieved was greater than for either method used alone. These findings confirm that biotyping affords excellent discrimination of strains of S. typhimurium and S. paratyphi B and indicate that the results obtained from biotyping can be interpreted with confidence.

Animals↗
PubMed1989

Characterisation of a fimbrial, mannose-resistant and eluting haemagglutinin (MREHA) produced by strains of Salmonella of serotype Sendai.

Strains of Salmonella of serotype Sendai, producing a mannose-resistant and eluting haemagglutinin (MREHA) when cultured at 37 degrees C but not at 18 degrees C, were examined by electronmicroscopy after negative staining. Production of this MREHA, previously thought to be nonfimbrial, was correlated with the presence of thick fimbriae with an external diameter of 13.6 nm. These fimbriae were readily fragmented and, when purified, had an estimated Mr of 28 Kda. Production of fimbrial MREHA by Sendai strains was associated with the ability to adhere to a wide range of substrates and to form a fimbrial pellicle at the surface of liquid media incubated statically in air. The origin of this unusual Sendai fimbrial MREHA is unknown. Thin filamentous structures produced independently of fimbrial MREHA by Sendai strains were also described. Fimbrial MREHA was not produced by strains of the antigenically similar serotype Miami which, however, and unlike Sendai strains, formed mannose-sensitive haemagglutinin and type-1 fimbriae. The ability to differentiate strains of Miami and Sendai (serotype 1,9,12:a: 1,5) by means of their fimbriae is noted.

Bacterial Adhesion↗
PubMed1989

The haemagglutinins and fimbriae of Proteus penneri.

The haemagglutinins and fimbriae produced by 18 strains of Proteus penneri were studied and compared with those formed by representative strains of other species of Proteeae. After repeated subcultures at 30 degrees C, 12 P. penneri strains formed only MR/K haemagglutinins which were associated with thin, non-channelled, type-3 fimbriae. Two strains formed simultaneously both MS and MR/K haemagglutinins associated with thick, channelled, type-1 fimbriae and type-3 fimbriae, respectively. Four strains formed simultaneously both MR/K and MR/P haemagglutinins. No P. penneri strain formed either MS or MR/P haemagglutinins alone under these conditions. The type-3 fimbriae from P. penneri strain E180 were isolated, purified and found to be protein of 19 Kda. Immunoelectronmicroscopy studies with antibody to the type-3 fimbriae of strain E180 showed that P. penneri strains at least two antigenic types of type-3 fimbriae. The type-3 fimbrial antigen of the vaccine strain E180 was shared by another eight strains of P. penneri. A further eight P. penneri strains and the strains representative of other genera within Proteeae had type-3 fimbriae of a different antigenic type. The formation of these haemagglutinins and fimbriae suggests that this organism is well endowed to be a urinary-tract pathogen.

Antigens, Bacterial↗
PubMed1989

Immunological and genetical relatedness of type-1 and type-2 fimbriae in salmonellas of serotypes Gallinarum, Pullorum and Typhimurium.

The fimbriae of 50 strains of serotype Gallinarum and 35 strains of serotype Pullorum of the genus Salmonella were compared with the type-1 fimbriae of serotype Typhimurium strains by immune electron microscopy and dot blot hybridization tests with gene probes for type-1 fimbriation in Typhimurium. The fimbriae of Gallinarum and Pullorum strains were coated with Typhimurium type-1 fimbrial antiserum and probes hybridized strongly with DNA of Gallinarum and Pullorum strains under stringent conditions. Furthermore, when Typhimurium type-1 fimbrial antiserum, that had been absorbed with fimbriate Gallinarum or Pullorum bacteria, was used in immune gold labelling experiments, it was shown that residual antibody recognized sites of possible adhesin incorporation at intervals along the length of Typhimurium type-1 fimbriae. These findings suggest that the type-2 fimbriae produced by all Gallinarum and Pullorum strains are non-adhesive forms of adhesive, type-1 fimbriae. This observation is of interest because type-1 fimbriae have never been reported in naturally occurring strains of these two avian-adapted serotypes.

Agglutination Tests↗
PubMed1988

Recurrent peritonitis caused by Serratia marcescens in a diabetic patient receiving continuous ambulatory peritoneal dialysis.

A diabetic patient treated by continuous ambulatory peritoneal dialysis for end-stage renal failure had recurrent peritonitis caused by Serratia marcescens. Thirty-eight isolates of S. marcescens recovered over a 14-month period from peritoneal-dialysis effluent, catheter tips and catheter-exit sites were biotyped and serotyped. The finding that most (90%) of these isolates belonged to the same biotype and serotype suggested that the patient had relapsing infections with the same strain. Similar isolates were recovered from the peritoneal dialysates of another two patients in the same ward, neither of whom developed Serratia-associated peritonitis.

Catheters, Indwelling↗