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Biomedical subjects

A Efstratiou

Publications and source records attributed to A Efstratiou.

At least 91 records · Page 5Linked to original sources
PubMed1994

Biochemical differences among human and animal streptococci of Lancefield group C or group G.

Pyogenic streptococci of Lancefield group C or group G from human or animal sources were examined with a view to increasing the number of diagnostic tests useful for their differentiation. Human strains of group G produced L-prolyl-L-arginine aminopeptidase but isolates of Streptococcus equisimilis (group C) did not. Tests for alpha-L-glutamate aminopeptidase together with fermentation of glycogen or sorbitol distinguished S. dysgalactiae from strains of S. equisimilis isolated from animals. It was confirmed that fermentation tests were helpful in the study of S. equi and S. zooepidemicus and that enzyme reactions helped distinguish between S. canis and the human strains of group G.

Aminopeptidases↗
PubMed1994

Polymerase chain reaction for screening clinical isolates of corynebacteria for the production of diphtheria toxin.

AIMS: To assess the performance of the polymerase chain reaction (PCR) when used to screen rapidly large numbers of corynebacteria for toxin production; and to determine the incidence of false positive PCR results with non-toxigenic Corynebacterium diphtheriae isolates. METHODS: Eighty seven recent British isolates of corynebacteria were assayed by PCR. All isolates were assayed from both blood and tellurite agar within a five day period. Thirty three non-toxigenic isolates of C diphtheriae from six countries were also tested by PCR and by the Elek immunodiffusion assay. RESULTS: There was complete concordance between the results of PCR and traditional methods on the recent British isolates, with one exception: an Elek positive "C ulcerans" isolate, which was PCR positive from tellurite but not from blood agar. One of the thirty three (3%) non-toxigenic isolates of C diphtheriae was PCR positive. CONCLUSIONS: These results suggest that PCR compares favourably with traditional methods for the detection of toxigenic corynebacteria and that it represents a powerful new tool in the diagnosis of an old disease.

Base Sequence↗
PubMed1993

Investigation of milk-borne Streptococcus zooepidemicus infection associated with glomerulonephritis in Australia.

An outbreak of infection due to Streptococcus zooepidermicus is reported. The index case was a patient who suffered an episode of septicaemia complicated by glomerulonephritis. Two other persons in his family were found to be asymptomatic throat carriers. The source of the outbreak was unpasteurised milk from a house cow on the farm where the family lived. Molecular studies confirmed that the strains isolated from the index case, the other family members and the cow's milk were identical. Although a renal biopsy was not performed, the diagnostic criteria for poststreptococcal glomerulonephritis were satisfied. The organism is an uncommon human pathogen that sometimes causes outbreaks of severe infection which may be associated with glomerulonephritis.

Animals↗
PubMed1993

The serotypes of Streptococcus pyogenes present in Britain during 1980-1990 and their association with disease.

A total of 16,909 cultures of Streptococcus pyogenes (Lancefield group A) isolated in Britain during 1980-90 were examined for T- and M-protein antigens. One or other M antigen was detected in 92.6% of the strains. The numbers of isolates of some serotypes, such as M3 and M12, did not show great variation from year-to-year, whereas there were nationwide epidemics, extending over several years, caused by strains of serotypes M1 and M49. Isolates of serotypes M1 and M3 were associated particularly with invasive disease and fatal infections. Representatives of serotypes M80, M81 and the provisional types PT180, PT1658 and PT5757 were isolated most often from cases of pyoderma. Erythromycin resistance was detected in 30 serotypes but one half of all of the resistant isolates belonged to serotype M4.

Bacteremia↗
PubMed1992

Screening tests for pathogenic corynebacteria.

AIM: To provide simple tests that would help in the identification of corynebacteria that produce diphtheria toxin. METHODS: A collection of 99 freshly isolated corynebacteria was assembled and the cultures identified by conventional tests confirmed by an identification kit. Modifications were made to procedures for preparation of the culture medium for the Elek test and to the test for detection of pyrazinamidase (pyrazine carboxylamidase) activity. These two together with an indicator medium for cystinase activity were applied to the collection of organisms. RESULTS: Cystinase was detected in all 61 members of the toxigenic species and none produced pyrazinamidase. In contrast, all but two of the 38 representatives of non-toxigenic species yielded pyrazinamidase and none formed cystinase. Of the 61 cystinase producing cultures (which were also pyrazinamidase negative), 21 gave a positive Elek test with the modified culture medium. A total of 30 of these 61 were tested for toxigenicity in guinea pigs and the results of the animal and plate tests concorded. At least seven cultures could have been reported as non-toxigenic if Elek tests based on media prepared in the conventional way had been the only test available. CONCLUSION: The three procedures described go some way towards meeting the needs of diagnostic laboratories for efficient procedures for distinguishing pathogenic corynebacteria.

Amidohydrolases↗
PubMed1992

Screening for Corynebacterium diphtheriae.

A throat swab from a 9 year old girl with pharyngitis yielded a non-toxigenic strain of Corynebacterium diphtheriae var mitis and Streptococcus group G. C pseudodiphtheriticum was isolated from the throats of two of her four brothers. In each case the isolate was sent to the reference laboratory before full identification. The growth was found to be mixed for one brother; the other isolate being a toxin producing C diphtheriae var gravis. The child was asymptomatic and the case proves that all colonial types on the Hoyles plate should be identified.

Child↗
PubMed1989

An outbreak of puerperal fever caused by group C streptococci.

Between 19 February and 18 April 1987, 33 confirmed cases of puerperal fever caused by Streptococcus equisimilis serotype T204 occurred at three hospitals in and around Chelmsford. Most of the cases (70%) occurred on one ward, in which toilet seats and a shower are believed to have aided transmission, although insufficient data were obtained to exclude a role for person-to-person spread. Possession of M-protein antigen was demonstrated in the outbreak strain.

Adult↗
PubMed1989

The presence of M proteins in outbreak strains of Streptococcus equisimilis T-type 204.

Cultures of Streptococcus equisimilis (Lancefield group C) from three outbreaks of illness were found to carry the T-protein antigen 204. Strains of this type were not otherwise represented in a collection of 743 cultures of these 'pyogenes-like' streptococci isolated from other outbreaks of infection or as random isolates. Two of the three outbreaks were of pharyngitis. The third arose in a maternity unit where the organism was isolated from mothers with puerperal fever, from staff and also from the environment. Representative strains were found to carry M-protein antigens as judged by their ability to survive and multiply in fresh normal human blood. Comparison of absorbed rabbit antiserum to the M antigens in opsonic and precipitin tests showed that a distinct M antigen was present on isolates from one outbreak of sore throat and that all cultures from the other two incidents shared a common M antigen. Samples of serum were also available from patients in the outbreak of puerperal sepsis. Most patients developed antibodies to one or more streptococcal antigens including the M protein, streptolysin O, streptokinase and the hyaluronidase specific for strains of group C and group G streptococci.

Antigens, Bacterial↗
PubMed1989

Outbreaks of human infection caused by pyogenic streptococci of Lancefield groups C and G.

Within a collection of 749 strains of group C streptococci (Streptococcus equisimilis) and 2348 of group G, isolated over a period of 6 years, there were clusters from 63 probable outbreaks of infection. These occurred in burns and maternity units, hospital wards, outpatient clinics, army camps and religious communities. Overall, it was possible to identify T-protein antigens in 88% of the group C strains and in 82% of group G. Serotyping by the identification of T-protein antigens was a useful method for the subdivision of these strains.

Cross Infection↗