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Biomedical subjects

R C Matthews

Publications and source records attributed to R C Matthews.

At least 37 records · Page 2Linked to original sources
PubMed1997

An epidemiological study of blood culture isolates of coagulase-negative staphylococci demonstrating hospital-acquired infection.

We applied pulsed-field gel electrophoresis (PFGE) after SmaI digestion and random amplification of polymorphic DNA (RAPD) analysis with nine oligonucleotide primers to 146 blood culture isolates of Staphylococcus epidermidis and 25 blood culture isolates of Staphylococcus haemolyticus. These were obtained over a 12-month period from patients on the neonatal and hematology units of the Central Manchester Health Care Trust. PFGE demonstrated two clusters of isolates of S. epidermidis (type A and type B) on the neonatal ward and a single cluster (type C) on the hematology unit. Type A was represented by 10 indistinguishable isolates from nine patients, type B was represented by 20 isolates from 14 patients, and type C was represented by 26 isolates from 10 patients. Type A isolates were resistant to chloramphenicol and type C isolates were resistant to ciprofloxacin, mirroring current antibiotic usage. There was no evidence of cross infection due to S. haemolyticus. RAPD analysis, on the basis of a single band difference, produced 58 types of S. epidermidis and 12 types of S. haemolyticus with primer 8 (ATG TAA GCT CCT GGG GAT TCA C; 5' to 3') and 54 types of S. epidermidis and 10 types of S. haemolyticus with primer 9 (AAG TAA GTG ACT GGG GTG AGC G; 5' to 3'). Combining the results confirmed cross infection. Types A, B, and C were concurrently isolated from the hands of the staff of the appropriate unit. Partial control was achieved by withdrawing ciprofloxacin use in the case of the hematology unit and improving hand hygiene in both units.

Coagulase↗
PubMed1996

The effect of an accelerated immunisation schedule on pertussis in England and Wales.

Notifications of pertussis in England and Wales have fallen dramatically from 65 810 during the epidemic year of 1982 to 3963 cases during the epidemic year of 1994, as vaccine coverage has risen. The incidence of pertussis has declined in all ages, including babies under 3 months of age who would have been at risk of disease from older siblings vaccinated under the accelerated schedule introduced in 1990 if immunity induced as result of this schedule had been short lived. To document the efficacy of the current whole cell vaccine under the accelerated schedule an enhanced surveillance scheme based on laboratory confirmed cases of pertussis was set up in 1994. Three deaths occurred in infants with confirmed pertussis, all of whom were under 8 weeks of age and unvaccinated. The overall vaccine efficacy for those over 6 months and under 5 years of age was 94%. This estimate may be inflated, as a number of biases could lead to the underascertainment of cases in vaccinated children, but it is similar to previous estimates obtained for children of the same age vaccinated under the 3, 5, and 10 month schedule. Vaccine efficacy was 89% for children aged over 5 and under 15 years. The enhanced surveillance scheme will enable us to monitor the duration of protection under the accelerated schedule and evaluate the continuing impact of pertussis infection.

Adolescent↗
PubMed1996

Defining antibody targets in Streptococcus oralis infection.

Immunoblotting of sera from 12 neutropenic patients with Streptococcus oralis septicemia and 18 patients with endocarditis due to viridans group streptococci revealed immunodominant S. oralis antigens at 85 and 180 kDa. The former cross-reacted with a mouse monoclonal antibody to hsp90. The latter was identified by sequencing positive clones obtained by screening a genomic expression library of S. oralis with pooled sera from patients who had been infected with S. oralis. Antibody eluted from one of these clones reacted with the 180-kDa antigen of S. oralis. Southern blotting confirmed the origin of the clone from S. oralis. The derived amino acid sequence showed 76.2% homology with the PAc protein precursor of Streptococcus mutans and 73.8% homology with the SpaA protein precursor of Streptococcus sobrinus. Epitope mapping of the derived amino acid sequence with sera from patients with viridans group streptococcal endocarditis delineated nine epitopes. Peptides 1 (TMYPNRQPGSGWDSS) and 2 (WYSLNGKIRAVDVPK), representing two of these epitopes, and peptide 3 (YEVEKPLEPAPVAPS), representing the repeat proline region, were synthesized. These three peptides were used to screen a phage antibody display library derived from a patient who had recovered from S. oralis infection. Two of the human recombinant antibodies produced (SORAL 3 and SORAL 4 against peptide 3) and a human recombinant antibody (B3.7) against the conserved epitope (LKVIRK) of hsp90 gave statistically significant protection, compared with control groups, in a mouse model of lethal S. oralis infection.

Amino Acid Sequence↗
PubMed1995

Application of pulsed field gel electrophoresis to the 1993 epidemic of whooping cough in the UK.

The purpose of this study was to DNA fingerprint the majority (64%) of isolates received at the Pertussis Reference Laboratory during the 1993 whooping cough epidemic by pulsed field gel electrophoresis of Xba I-generated restriction digests. Two DNA restriction patterns, types 1 and 3, predominated (40% and 23%, respectively, of 180 isolates) but type 2, identified in a previous study was notably absent. Twenty-one new DNA types occurred (24% of isolates), some being atypical as bands 155-230 kb were no longer conserved, but there was no statistically significant difference in their incidence in the upswing (June-September) compared to the downswing (October-December) phase of the epidemic. There was a relatively high proportion of new types, compared to type 1, at the peak (September). About 50% of isolates received were from the North Western Region, where 44% of isolates were DNA type 1. Whereas only 1 out of 10 isolates from Scotland were of this type, suggesting some geographic variation. Statistically significant findings included a higher proportion of isolates from female patients (P < 0.01), most marked in the 12-24 months age group (P < 0.05); a higher proportion of infants under 12 months requiring hospital admission compared to older children (P < 0.05); and a greater number of isolates from unvaccinated children (P < 0.01). Analysis of serotype according to four age groups (under 3 months, 3-12 months, 12-24 months and above 2 years) showed statistically significant differences (P < 0.05) with a noticeably lower proportion (38%) of serotype 1,3 in 3-12 months age group and higher prevalence (74%) of serotype 1,3 in the 12-24 months age group. There was no correlation between DNA type and serotype.

Age Factors↗
PubMed1995

Defining potential targets for immunotherapy in Burkholderia cepacia infection.

Burkholderia cepacia has become a serious source of infection in patients with cystic fibrosis. Antibiotic therapy is difficult as the bacteria are intrinsically resistant to most antibiotics. The present study compared the antibody response by immunoblot of 50 negative control sera, 22 patients with cystic fibrosis and no evidence of B. cepacia, 9 clinically well patients with cystic fibrosis colonised by B. cepacia and 5 patients with cystic fibrosis and deteriorating or fatal B. cepacia infection. Nineteen antigenic bands varying in apparent molecular weights from 19 to 170 kDa were identified. Two bands at 19 and 21 kDa were only present when the organism was grown in an iron-deficient medium. The band at 30 kDa was identified as a porin and the possession of IgG antibody carried a statistically significant (P = 0.00003) better prognosis. This antigen was thus a potential target for immunotherapy.

Antibodies, Bacterial↗
PubMed1994

Epitope mapping human heat shock protein 90 with sera from infected patients.

Epitope mapping with sera from a range of infected patients showed that antibodies are commonly produced which cross-react with a number of epitopes on human heat shock protein 90 (HSP 90). Such autoreactive antibodies were particularly frequent in patients suffering from systemic candidiasis (9 patients), invasive aspergillosis (6 patients), ABPA (2 patients), a patient with aspergilloma and one with malaria. The patient with malaria recognized similar epitopes to those with invasive aspergillosis and candidiasis including the highly conserved epitope LKVIRKVIRK and an epitope NNLGTI which was otherwise only recognised by patients with candidiasis. Crossreacting antibodies to relatively few epitopes occurred in patients with Enterococcus faecalis and Corynebacterium jeikeium endocarditis. This was contrasted with the results from 6 patients with systemic lupus erythematosus (SLE) who were positive on immunoblot against fungal HSP 90. These did not react with the above epitopes but reacted with other areas within human HSP 90.

Amino Acid Sequence↗
PubMed1993

A comparison of the DNA fragment patterns of the mouse-virulent challenge strains and clinical isolates of Bordetella pertussis.

The DNA fragment patterns of two mouse-virulent strains of Bordetella pertussis, commonly used in animal protection tests, were compared to those of clinical isolates. Strain W.18-323 and six variants were examined together with strain 353/Z and two variants. Chromosomal DNA was digested with the rare-cutting enzyme Xba I in order to produce relatively large fragments resolved by pulsed-field gel electrophoresis. The resulting DNA fragment patterns of strain 353/Z and those of its variants were indistinguishable from those of the commonest DNA type among clinical isolates. In contrast, strain W.18-323 and its variants showed a distinct genetic type, different from clinical isolates of B. pertussis, B. parapertussis or B. bronchiseptica. This finding, together with some phenotypic anomalies of this strain, raises doubts as to the suitability of W.18-323 as a challenge strain for assessing the efficacy of vaccines in the mouse model.

Animals↗
PubMed1993

Genetic relatedness of Bordetella species as determined by macrorestriction digests resolved by pulsed-field gel electrophoresis.

The genetic relatedness of the three medically important Bordetella species was examined by macrorestriction digestion of DNA with the rarely cutting enzyme XbaI and resolution by pulsed-field gel electrophoresis. Our data showed that Bordetella pertussis, Bordetella parapertussis, and Bordetella bronchiseptica produced species-specific macrorestriction profiles and that there was some variation between different isolates of the same species. Conserved bands at 130 and 155 kb occurred with B. pertussis (130 isolates tested), but the nine variable bands between 200 and 412 kb distinguished 21 types. The 10 isolates of B. parapertussis tested produced up to 11 bands at 118 to 375 kb, 4 of which were variable, giving three types. The eight B. bronchiseptica isolates examined produced up to 16 hands at 118 to 394 kb, 11 of which were variable, giving three types. The results of this work are compared with the results of previous DNA-DNA hybridization and multilocus enzyme electrophoresis studies which suggested that these three species are closely related and should be considered members of the same species.

Bordetella↗