Coagulase-negative staphylococci, and in particular Staphylococcus epidermidis, are now being recognized as causing human infections with increasing frequency; the absence of an internationally accepted system of phage-typing for coagulase-negative staphylococci led us to isolate new phages. Fifty strains of S. epidermidis isolated from human infections were induced with mitomycin C: eight phages (41, 63, 118-II, 138, 245, 336, 392 and 550) were isolated. These phages were propagated on five different strains of S. epidermidis. Their phages were propagated on five different strains of S. epidermidis. Their lytic activity as studied on 561 strains. Phages 336, 392 and 550 had a different host-range and different propagative strains; they typed 93% of the strains susceptible to the 8 phages. The other phages had an activity similar to that of phage 336. Twenty-one per cent of non-epidemic strains were susceptible to at least one of the three phages. The reproducibility, specificity and discriminatory power of these phages suggest they may be a useful addition to previously recognized phages.

Bacteriophage Typing↗

PubMedDate not supplied

[Serological diagnosis of Staphylococcus aureus infections using anti-A beta telchoic acid antibodies assay (author's transl)].

225 contol subjects, 12 hospitalized staphylococcus free (34 sera) and 16 S. aureus infected patients (79 sera) were tested for anti-A beta teichoic acid antibodies, using counter-immunoelectrophoresis. Anti-alpha and gamma haemolysins antibodies were dosed in parallel in 164 sera. Less than 5 per cent of control sera (3,11 per cent) have an antibody titre higher than 1/8; this titre is therefore selected as threshold level of positivity. Ten of the 12 hospitalized patients without staphylococcal infections are below this level. 31,6 per cent of staphylococcus infected patients have higher serum titers; only 3,7 per cent have no antibodies. In the others, a significant rise in titres is observed. There is no correlation between anti-alpha and gamma staphylolysin and anti-teichoic acid antibodies titres. The method suggested, both easy and rapid, could be used in association with anti-staphylolysin dosage for serological diagnosis of staphylococcal infections.

Adult↗

PubMedDate not supplied

[Prevalence of exfoliatin-producing strains in phage group II "Staphylococcus aureus" (author's transl)].

Prevalence of exfoliatin production has been investigated in 100 strains of Staphylococcus aureus, bacteriophage group II, by inoculation into newborn mice. Serotyping, detection of protein A and antibiotic susceptibility tests have also been performed. Thirty-one strains (31%) were toxin producers; they all produced a yellow pigment; there was no difference in phage attacks between toxinogenic and non-toxinogenic strains; but exfoliatin production was significantly associated to the presence of agglutinogens h2 and 263-2; rate of protein-A presence and of antibiotic susceptibility did not differ between the two groups of strains. In addition, toxin production has been investigated in 31 isolates from various skin lesions; 9 were found toxinogenic (8 amongst them had been cultivated from bullous lesions); most of them belonged to phage group II and possessed agglutinogens h2 and 263-2. So, in order to carry out the diagnosis of some bacterial skin infections, clinical symptoms, pathological and bacteriological data must be compared; the latter must include phage-typing, serotyping and exfoliatin detection.

Anti-Bacterial Agents↗

PubMedDate not supplied

[Detection of "Staphylococcus aureau" protein A on selective culture media (author's transl)].

Production of protein A by 100 various animal strains and 106 human strains of Staphylococcus aureus has been detected by conditioned haemagglutination after growth on seven different culture media: agar medium at n degrees 2 and Columbia agar with and without nalidixic acid (10.8 micrograms/ml), Baird-Parker, Chapman and tellurite-glycine-agar media. Rate of protein A-producing strains is as high on nalidixic acid media as on the same media without antibiotic. Baird-Parker, Chapman and tellurite-glycine-agar media are not convenient for protein A detection.

Culture Media↗

PubMedDate not supplied

[Sterilization by ionizing radiations (author's transl)].

The first part summarizes the general characteristics of ionizing radiations and their activity on microorganisms: lethal and mutagenic effects, sensitivity conditions. Different microbial species have different sensitivities: gram negative bacteria are more sensitive (D10 approximately 5-10 Krads), bacterial spores and viruses are more resistant (D10 approximately 1 Megarads). The second part considers the main applications of radiosterilization: some are at present in full development (medical and surgical disposable equipment); others are still at the experimental stage. Practical aspects, determination of sterilizing doses and control of radiosterilization are also described.

Bacteria↗