[Identification of some atypical (morpho-cultural and enzymatic) characteristics of E. coli strains isolated in different clinical and epidemiological conditions]. / Identificarea unor caractere atipice (morfo-culturale si enzimatice) la tulpini de E. coli izolate în diferite conditii clinico-epidemiologice.

From among the 2813 E. coli strains isolated from various specimens (urine, feces, pharyngeal exudates, organs from fowls) in the course of two years, the authors selected and carried out a complex study on the strains exhibiting atypical features, considered to give rise to errors of diagnosis. Of the 2813 strains studied, 599 (21.29%) presented different atypical traits : 45 (1.59%) morphological and cultural (very small pulvurelent colonies or extremely mucous, oily colonies), 21 (0.74%) morphological, cultural and enzymatic atypical aspects and 533 (18.96%) only enzymatic (non-indolegenous strains, strains giving a methyl red reaction, H2S positive strains, lactose-negative and adonite or inosite-positive strains).

[Sensitivity of Serratia marcescens to chemotherapy]. / Sensibilitatea la chimioterapice a Ser. marcescens.

The sensitivity of 112 S. marcescens strains, isolated under various clinico-epidemiologic conditions, was tested by the dilution in agar method against 10 different antibiotics and sulfonamides active against Gram-negative bacteria. With the maximum concentrations used only Gentamycin and nalidixic acid were active against a high proportion of the strains tested, i.e. 96.4% and 91.1%. Kanamycin, Neomycin, Chloramphenicol, Streptomycin and Tetracyclin had an inhibitory effect against less than 25% of tested strains. One strain was resistant to all the antibiotics, 49.1% were only sensitive to 2 antibiotics and 33.9% to 3 antibiotics. Among tested strains 22 different antibiotypes were established. Evidence of 2 or more types of resistance within the same epidemic outbreaux, reduces the value of the "antibiotype" as epidemiologic indicator within this species. The readily acquired transfer factors of resistance might be responsible for the marked "mobility" of the antibiotypes, as well as for the spread of S. marcescens in hospital pathology.

[Value of some enzyme tests used in practice for identification of enterobacteria]. / Valoarea unor teste enzimatice folosite în practica de identificare a enterobacteriilor.

A restricted biochemical scheme for the identification of enterobacteria, consisting of 12 enzymatic tests, of which 7 performed on the multitest TSI and MIU media (H2S, the production of acid and gas from glucose, fermentation of lactose/saccharose, mobility, urease and indol production) and 5 additional tests performed separately : lysindecarboxylase, phenylalanindeaminase, beta galactosidase, increase on citrate media and splitting of sodium malonate is proposed. Of 7782 coprocultures, 275 were selected on TSI and MIU media as belonging to one of the groups of known pathogenic enterobacteria ; 94.87% of these cultures were correctly identified by using the 5 additional tests alone. Of the 14 cultures that could not be listed taxonomically, 10 gave atypical reactions with at least one of these tests. The current use of this restricted scheme and the use of the more extensive sets only in doubtful cases presents a real advantage by reducing the volume of work and materials under satisfactorily accurate conditions for identification.