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Biomedical subjects

A Efstratiou

Publications and source records attributed to A Efstratiou.

99 records · Page 6Linked to original sources
PubMed1987

Characterization of Streptococcus zooepidemicus (Lancefield group C) from human and selected animal infections.

We assembled an international collection of strains from sporadic and epidemic human infection with Streptococcus zooepidemicus (Lancefield group C) for laboratory study. Cultural and physiological characteristics of the isolates were determined, including biotyping with the API 20 STREP test kit and susceptibility testing with penicillin, erythromycin and tetracycline. The strains were examined for bacteriocin production and sensitivity and typed with a specially developed group-C streptococcal bacteriophage system incorporating a panel of 14 phages. Results of these tests gave useful discrimination between many of the strains: differences were shown between each of the major outbreak strains, including those complicated by post-streptococcal glomerulonephritis. Serious group C streptococcal infection may be caused by S. zooepidemicus and isolates should be identified to species level; the application of a typing scheme such as this may help to distinguish epidemiological patterns of infection.

Animals↗
PubMed1984

Experience with ciprofloxacin in vitro and in vivo.

1-Cyclopropyl-6-fluoro-1-dihydro-4-oxo-7-(1-piperazinyl)-1,4-dihydro-3- quinolinecarboxylic acid (ciprofloxacin, Bay-o 9867) a new quinoline carboxylic acid derivative, was tested in vitro against 233 various Gram-negative microorganisms, mostly resistant to nalidixic acid. Minimal inhibitory concentrations (MIC) against the Enterobacteriaceae and P. aeruginosa ranged between less than 0.003 to 1 mg/l and less than 0.003 to 8 mg/l respectively with MIC90 of 2 mg/l. However, when sensitivities were repeated with an acid broth they were increased by greater than or equal to 32 fold. This effect was more prominent when as nutrient pooled human urine was used and particularly for P. aeruginosa strains. Ciprofloxacin at a dose of 250 mg, or 500 mg, 12-hourly for 10 days was randomly given to 40 patients aged 23-76 years, suffering from upper (27) and lower (13) urinary tract infections (UTI) as proved from the "antibody coated bacteria" (ACB) test. Pathogens included E. coli (20), Proteus sp. (13), K. pneumoniae (1), C. freundii (1) and P. aeruginosa (5), with MICs between less than 0.06 to 2 mg/l. During treatment all but one of the patients responded favorably both clinically and bacteriologically, while at a six-week follow-up, nine patients with upper UTIs and underlying chronic pyelonephritis or/and structural abnormalities had relapsed, while only one became reinfected. Treatment schedule did not influence the results. No appreciable side effect or toxicity was observed. It is concluded that ciprofloxacin should have an important role to play in the treatment of UTI as well as in systemic infections whenever multiresistant pathogens are implicated.

Adult↗
PubMed1983

The serotyping of hospital strains of streptococci belonging to Lancefield group C and group G.

A collection of more than 300 strains belonging to either Lancefield group C or group G was made. The cultures had been isolated either sporadically from patients with serious disease or as apparent clusters from various nosocomial outbreaks. T-protein antigens were sought. So far, nine distinct serotypes have been found among the group G streptococci and seven serotypes amongst the Streptococcus equisimilis (group C) strains. Of the sixteen serotypes, four were the original T-types 7, 16, 20 and 21 described by Griffith (1934). Because of the similarities of representatives of the two groups to Lancefield group A streptococci (Griffith, 1934; Maxted & Potter, 1967) a few strains not unexpectedly carried T antigens usually seen in group A streptococci. Using this scheme it has been possible to serotype 76% of S. equisimilis strains of human origin and 82% of group G streptococci from human clinical material. A small collection of group C and group G streptococci of animal origin could not be serotyped with the experimental T-antisera.

Agglutination Tests↗
PubMed1979

Serological grouping of streptococci by slide agglutination.

Streptococcal grouping sera for groups A, B, C, and G prepared for conventional testing by precipitation were made specific by absorption and used to identify streptococci by slide agglutination with and without staphyloccocal coagglutination. Trypsinised suspensions of 1055 strains, identified by precipitation as belonging to group A, B, C, or G, were tested by slide agglutination. Of these, 998 were correctly identified using a streptococcal suspension and antisera alone and a further 65 were identified when a loopful of protein A-positive staphylococci was added. Suspensions of 88 strains not of groups A, B, C, or G gave no reaction in the agglutination test with or without the addition of staphylococci. Group polysaccharide extracted by conventional methods also caused agglutination of staphylococci on a slide when specific antiserum was added. Growth from primary or secondary cultures digested in streptomyces enzyme for only 15-30 minutes provided an excellent antigen for a quick and simple method of streptococcal grouping using non-sensitised staphylococcal suspension and specific antisera for coagglutination.

Agglutination Tests↗
PubMed1973

The ortho-nitrophenol (ONPG) test and acid from lactose in Gram-negative genera.

The results are given of the ortho-nitrophenol test for beta-galactosidase production (ONPG test) on 588 strains of 123 aerobic species of bacteria, representing 30 genera. Apart from some strains of Erwinia herbicola (synonym Chromobacterium typhiflavum) and of Yersinia spp, these strains were not members of the Enterobacteriaceae, in which family the ONPG test is widely used and well documented. The strains were also tested for acid production from 1, 5, and 10% lactose and the findings are discussed in relation to the ONPG test.

Bacteria↗
PubMedDate not supplied

emm typing and validation of provisional M types for group A streptococci.

This report discusses the following issues related to typing of group A streptococci (GAS): The development and use of the 5' emm variable region sequencing (emm typing) in relation to the existing serologic typing system; the designation of emm types in relation to M types; a system for validation of new emm types; criteria for validation of provisional M types to new M-types; a list of reference type cultures for each of the M-type or emm-type strains of GAS; the results of the first culture exchange program for a quality control testing system among the national and World Health Organization collaborating centers for streptococci; and dissemination of new approaches to typing of GAS to the international streptococcal community.

Antigens, Bacterial↗
PubMedDate not supplied

[Genetic structure of Corynebacterium diphtheriae strains isolated in Russia during epidemics of various intensity].

The genetic structure of C. dipthteriae toxigenic strains isolated in Russia during the period of more than 50 years was analysed. The use of the method of ribotyping made it possible to register 17 C. diphtheriae ribotypes. The study revealed that the genetic structure of C. diphtheriae population varied in the dynamics of the epidemic process: each epidemic cycle characterized by predominant spread of epidemic strains of definite biovars and ribotypes. Thus, C. diphtheriae strains of biovar gravis, ribotype M11, dominated in the 40-60 years and C. diphtheriae strains of biovar mitis, closely related ribotypes M1 and M1v, dominated in the 80 years. During the last epidemic rise of diphtheriae morbidity in the 90 s C. diphtheriae strains of biovar gravis, closely related ribotypes G1 and G4, dominated among circulating strains. The proportion of these ribotypes began to increase 3 years before the rise of morbidity. The data of microbiological monitoring are recommended for use in the prognostication of the development of the epidemic process of diphtheria infection.

Corynebacterium diphtheriae↗