Distribution of the synergistic haemolysin genes hld and slush with respect to agr in human staphylococci.

Several staphylococcal species express a synergistic activity which potentiates hemolysis by beta-hemolysin. In Staphylococcus aureus, this activity is mediated by the delta-hemolysin, coded by the hld gene within the agr locus. In S. lugdunensis, the equivalent activity results from the production of 3 small peptides coded by an operon named slush, distinct from hld and located outside the agr region. We examined 15 clinically relevant staphylococcal species for the presence of hld, slush and agr by specific hybridisation. All species contained a recognizable agr-related locus. Three species never produced synergistic haemolysis and contained neither hld nor slush. Of the 12 producer strains, 5 contained hld, apparently within the agr region, 4 contained slush and one (S. caprae) contained both. Two other producer species (S. hominis and S. simulans) hybridised to neither probe.

Staphylococcus pasteuri-specific oligonucleotide probes derived from a random amplified DNA fragment.

A rapid polymerase chain reaction method was developed to differentiate Staphylococcus pasteuri from other staphylococcal species, especially the phenotypically similar S. warneri. The oligonucleotide probes used as primers were designed from the sequence of a S. pasteuri random amplified polymorphic DNA fragment.

Characterization of clinically significant isolates of Staphylococcus epidermidis from patients with endocarditis.

Biotyping, slime production, bacteriophage typing, serotyping, antibiograms, and plasmid profiles were used to characterize 19 Staphylococcus epidermidis strains isolated from 12 patients with prosthetic valve endocarditis and from 7 patients with native valve endocarditis. With the API Staph battery, 12 different biocodes with, at the most, three differences were obtained. Slime production was found for 10 strains (53%). Agglutinogens investigated by agglutination with two specific sera were found for 12 strains (63.1%). Three strains were phage typable (15.2%). Against a panel of nine antimicrobial agents, 15 different profiles were found. Multiply antibiotic-resistant strains were isolated from patients with prosthetic valve endocarditis when disease onset occurred less than 18 months after heart surgery and from patients with native valve endocarditis who received antibiotics immediately prior to their illness. All of the strains were available for plasmid analysis, and all the DNA profiles were distinct. On gels run in Tris-borate buffer, 73.7% of the strains had large plasmids of more than 30 megadaltons. A small plasmid of 2.8 megadaltons was found in multiply resistant strains and in strains resistant only to tetracyclines. None of the isolates appeared to be the same strain, and the bacteriological differences between the strains were confirmed mainly by the antibiotic susceptibility profile and the plasmid pattern analysis. These bacteriological results were in agreement with the clinical data.

[Growth of Staphylococcus aureus Cowan I in the presence of subbactericidal concentrations of povidone-iodine]. / Croissance de Staphylococcus aureus Cowan I en présence de concentrations infrabactéricides de polyvinylpyrrolidone iodée.

Staphylococcus aureus, strain Cowan I, is cultivated in the presence of povidone iodine (PVP.I) at the concentration of 0, 640, 960 micrograms/ml; growth curves points are platted (OD 640 mm) at 0, 1, 2.50, 3, 4.50, 7 and 24 hours. Growth curves in the presence of povidone alone as well as in the standard without antiseptic are similar and reproducible. A bacteriostatic effect is observed with 640 micrograms/ml PVP.I concentration compared to an incomplete bactericidal effect with 960 micrograms/ml concentration. Proteinee A detected by conditioned hemagglutination method is present in the centrifugation pellet of the standard and only in the supernatant of the test samples during the early phases of the growth. Production of alpha-ribitol-teichoic acid detected by counterimmunoelectrophoresis is not significantly different in the standard and in the presence of antiseptic. Biochemical characteristics studied by Api Staph gallery are identical for the control strain and the strain grown in the presence of PVP.I. Observed by scanning and transmission electronic microscope the bacterial cells do not present structural modification during growth with PVP.I.

[Bacteriologic study of 125 cases of infectious streptococcal endocarditis]. / Etude bactériologique de cent vingt-cinq endocardites infectieuses à streptocoque.

Streptococci remain the bacterial group the most frequently associated with microbial endocarditis. This paper points out the ability of the different species to cause endocarditis. 128 streptococci are isolated from patients with microbial endocarditis (127 from blood cultures, 1 from a valve). Isolates are speciated by biochemical tests and the determination of their group antigen. The viridans streptococci most frequently isolated are S. sanguis I (27 p. cent), S. mitis (16,5 p. cent) and S. sanguis II (9,6 p cent). A comparative survey of the results is rather difficult due to the methodological and taxonomical divergences.

[Bacteriologic study of 125 cases of streptococcal infectious endocarditis]. / Etude bactériologique de cent vingt-cinq endocardites infectieuses à streptocoque.

Streptococci remain the bacterial group the most frequently associated with microbial endocarditis. This paper points out the ability of the different species to cause endocarditis. 128 streptococci are isolated from patients with microbial endocarditis (127 from blood cultures, 1 from a valve). Isolates are speciated by biochemical tests and the determination of their group antigen. The viridans streptococci most frequently isolated are S. sanguis I (27 p. cent), S. mitis (16.5 p. cent) and S. sanguis II (9.6 p cent). A comparative survey of the results is rather difficult due to the methodological and taxonomical divergences.