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Biomedical subjects

E M Cooke

Publications and source records attributed to E M Cooke.

At least 37 records · Page 2Linked to original sources

Evaluation of electrophoretic methods for typing methicillin-resistant Staphylococcus aureus.

Three electrophoretic methods of typing methicillin-resistant Staphylococcus aureus (MRSA) strains--plasmid profiles (PP), whole-cell protein profiles (WCPP) and immunoblotting profiles (IP)--were evaluated and compared with phage typing. The results obtained with isolates from 12 outbreaks were compared both within the outbreaks, to determine the consistency of results, and between outbreaks. There was generally good agreement between the typing methods but in only six outbreaks did all four methods indicate the same relationship between isolates. WCPP comprised more than 50 bands; when differences occurred, they were seen in only a few bands. In contrast, IP comprised only one or two major bands and the differences were much easier to interpret. The PPs of many of the isolates were similar; many isolates contained a plasmid of mol. wt (18-25) x 10(6). In several outbreaks both WCPP and IP showed minor differences between isolates that were not apparent with phage typing. When comparisons were made between the 12 index strains and an isolate representing the London epidemic MRSA strain, phage typing and WCPP were the most discriminatory methods; both gave nine distinct patterns, whereas there were eight IPs and only six PPs amongst the 13 strains. It was concluded that both WCPP and IP could provide valuable epidemiological data on MRSA and that IP was the easiest of the three methods to interpret.

Bacterial Proteins↗

Comparison of faecal florae in patients with rheumatoid arthritis and controls.

The faecal flora of 25 out-patients with active rheumatoid arthritis (RA) was compared with that of 25 age- and sex-matched controls. A comprehensive survey revealed a significantly higher carriage rate of Clostridium perfringens in the RA population (88%) than controls (48%) (p less than 0.01). Coliform counts also tended to be higher, but there were no other significant differences between patients and controls. When the study was enlarged to include a further 113 RA patients with variable disease activity and a further 38 controls, clostridia were again more frequently carried by those with RA (70%) than controls (45%) (p less than 0.01) and clostridial counts were significantly higher in the patient group (p = 0.006). Moreover, counts in patients with active or moderately active disease were significantly higher than in those with inactive disease (p less than 0.001). These data are consistent with the hypothesis that Cl. perfringens plays a role in triggering or is otherwise associated with disease activity in RA. The findings may be alternatively an effect of the disease or its treatment with, for example, anti-inflammatory drugs.

Arthritis, Rheumatoid↗

Effects of sulphasalazine on faecal flora in patients with rheumatoid arthritis: a comparison with penicillamine.

Twenty-six out-patients with active rheumatoid arthritis (RA) were randomly allocated to treatment with sulphasalazine (SASP) or D-penicillamine (DPA). Faecal samples were collected from all patients at 4-weekly intervals and examined for changes in faecal flora during treatment. Both treatment groups showed substantial clinical improvement. In the SASP-treated group this was accompanied by significant falls in counts of Cl. perfringens and E. coli. No such changes were seen in the DPA-treated group. These results suggest that SASP's efficacy in RA may be related to its antibacterial properties.

Arthritis, Rheumatoid↗

Avidin-biotin-peroxidase complex immunohistochemistry to detect immunoglobulin in formalin fixed skin biopsies in canine autoimmune skin disease.

Avidin-biotin-peroxidase complex immunohistochemistry was used on formalin fixed, paraffin embedded, trypsin digested, skin biopsies to detect immunoglobulin deposition in dogs with autoimmune skin disease. Immunostaining by the avidin-biotin-peroxidase complex technique revealed intercellular and/or basement membrane immunoglobulin deposits in 27 of 28 dogs considered to have autoimmune skin disease by clinical and histological evaluation and in six of 19 dogs considered to have autoimmune skin disease by clinical evaluation but without histological confirmation. Similar immunostaining was not evident in five biopsies of normal skin or in biopsies from four dogs with noninflammatory dermatoses, but was present in biopsies from one of ten dogs considered by clinical and histological criteria to have an inflammatory dermatosis other than autoimmune skin disease. Detection of immunoglobulin deposits in skin biopsies by avidin-biotin-peroxidase complex immunohistochemistry offers numerous advantages over conventional immunofluorescence methods including the opportunity to precisely compare histological and immunological findings.

Animals↗

Antibiotic resistance monitoring, with particular reference to methicillin-resistant Staphylococcus aureus.

Two surveys of antibiotic resistance in hospital pathogens are described. The first is a long-term, multi-center, laboratory based investigation in which antibiotic resistance data from laboratories with computerized reporting is collected. The difficulties of this type of investigation are discussed and some solutions suggested. In the second investigation reports of the isolation of methicillin-resistant Staphylococcus aureus (MRSA) were collected from microbiological laboratories on a nation-wide basis. The results were useful in monitoring the spread of the organism and in its control.

Cross Infection↗

Methicillin-resistant Staphylococcus aureus in the UK and Ireland. A questionnaire survey.

The results of a questionnaire survey of the distribution of methicillin-resistant Staphylococcus aureus (MRSA) in the UK and Ireland between 1982 and 1983 are reported. Information was obtained about the geographical distribution of MRSA, the units affected, the sites of isolation and the preventive measures employed. Serious clinical problems were confined to a small number of hospitals with high isolation rates of MRSA.

Cross Infection↗

Polyagglutinating and non-typable strains of Pseudomonas aeruginosa in cystic fibrosis.

Serologically polyagglutinating (PA) and non-typable (NT) strains of Pseudomonas aeruginosa are frequently isolated from cystic fibrosis (CF) patients, but are uncommon in other patients. From serologically typical parent strains, we isolated two variants (one PA, the other NT) which differed from the parent in bacteriophage susceptibility or in sensitivity to the bactericidal action of normal human serum. The PA and NT variants (strains 7/1 and 18S respectively) reacted with antiserum to the parent strains 7 and 18R but did not absorb homologous specific O antibody from antiserum to the parent strains. In contrast the parent strains absorbed anti-PA and anti-NT antibodies from antisera to the variant strains. The yield of lipopolysaccharide (LPS) from acetone-dried cells of the parent strain 7 was similar to that of the PA derivative; but the NT strain 18S yielded only half the LPS of its parent strain. LPS of the variant 7/1 gave a banding profile by SDS-PAGE similar to that of the parent LPS 7, but lacked high-molecular-weight components. LPS of the variant 18S appeared to be grossly different in profile from LPS 18R. Of 533 isolates of P. aeruginosa that were tested with O antisera and with antisera to the two variants, 15% were O-typable and 22% were O-non-typable; 26% reacted with anti-PA serum alone, 10% with anti-NT serum alone, and 27% were agglutinated by both sera. There was a statistically significant correlation between serum sensitivity of CF isolates and their reaction with the PA or NT antisera.

Agglutination Tests↗

An investigation of the spread of gentamicin resistance in a district general hospital.

A cluster of infections caused by gentamicin-resistant gram-negative bacilli in a District General Hospital was investigated. The plasmids coding for gentamicin resistance in the infecting organisms and in isolates obtained from the ward environment and from the faeces of patients and staff were characterised. Six plasmids encoding gentamicin resistance were recognised amongst the organisms causing infection. Two of the plasmids were found in different serotypes of the same species and one plasmid was found in different genera. Three of the plasmids present in the organisms causing the infections were also present in the inanimate environment or in the bowel flora of patients and these also were found in different serotypes of the same species and in different genera.

Conjugation, Genetic↗

Adhesive tapes in the special care baby unit.

Semi-quantitative sampling of 37 taped sites and 37 matching control sites in 30 babies in a special care baby unit showed a tendency for bacterial growth under the cardiac monitors or the occlusive plastic adhesive tape to be greater than at the control site. This tendency was demonstrable even when potential pathogens were considered. During the study, an outbreak due to Candida albicans occurred. Antibiotic resistance of coagulase-negative staphylococci was marked and this, and other evidence, suggested that part of the skin flora was acquired from the unit.

Adhesives↗

Escherichia coli in retail processed food.

Four thousand two hundred and forty six samples of retail processed food were examined for the presence of Escherichia coli. Overall 12% of samples contained this organism, cakes and confectionery being more frequently contaminated (28%) than meat and meat based products (9%). Contamination was more frequent in the summer months than in the colder weather and 27% of the contaminated foods contained greater than 10(3) E. coli/g. E. coli from meat and meat based products were more commonly resistant to one or more antibiotics (14%) than were confectionery strains (1%). The significance of these findings in relation to the E. coli population of the human bowel is discussed.

Anti-Bacterial Agents↗

Attempt to modify klebsiella carriage in ankylosing spondylitic patients by diet: correlation of klebsiella carriage with disease activity.

Patients with ankylosing spondylitis were asked to follow a 'klebsiella exclusion diet' for 5 months of a 10-month study. The same percentage of faecal samples were positive for klebsiella whether the patients were on or off the experimental diet. The diet also failed to influence variability of klebsiella serotypes. We found no correlation between acquisition of klebsiella and deterioration of disease symptoms, as recorded by the patients. Furthermore, carriage of klebsiella did not correlate with any of the following parameters of disease activity measured in the outpatient clinic: morning stiffness, pain measured on a visual analogue scale, analgesic consumption, ESR, total serum IgA. We found no evidence, therefore, that faecal klebsiella is involved in disease exacerbations of ankylosing spondylitis.

Adult↗

Pathogenesis of seronegative arthritis.

The concept of seronegative spondarthritis, linking several diseases around ankylosing spondylitis, has received considerable clinical and genetic support, especially through the discovery of a high frequency of HLA-B27 in these disorders. Exogenous factors would appear to be responsible for some manifestations of the disease, but the role of Klebsiella micro-organisms is equivocal, and dietary control does not affect clinical manifestations. Increased serum and salivary IgA antibodies in active ankylosing spondylitis patients tend to suggest that IgA may act as an acute-phase reactant.

HLA Antigens↗