[Strains of Salmonella with atypical biochemical activity found in diagnostic material]. / Paleczki Salmonella o nietypowej aktywnosci biochemicznej wystepujace w materiale diagnostycznym.

Biochemically atypical strains belonging to 11 genera of Salmonella subspecies I in the number of 200 were collected in Poland in the years 1980-1991 were tested by means of 22 biochemical tests. Atypical property stability was detected in 164 strains. Most stable properties were following: ability to ferment lactose, lack of ability of dulcitol fermentation, lack of hydrosulfide production and lack of lysine decarboxylation. Atypical properties were occurring singularly or clusters numbering two or three. Identification procedure for Salmonella accepted in this country enables proper diagnosis of an atypical strain, however it requires application of supplemental biochemical tests. These strains were tested for susceptibility of 15 antimicrobial agents and no correlation between antibiotic resistance and occurrence of one or several atypical properties has been found.

[Bacteriophage types represented by lactose-fermenting Salmonella agona strains]. / Typy bakteriofagowe reprezentowane przez szczepy Salmonella agona fermentujace laktoze.

Bacteriophage typing was performed on 1911 S. agona, lactose-fermenting strains. These strains were isolated from hospitalised newborns and neonates patients. Out of 1911 strains 98.8% were typable by means of phage set prepared for strains differentiation of Salmonella agona showing typical biochemical properties. It was shown that in 16 provinces from which the strains were obtained in 1983-1985 type V (49.5%) and type XI (25.4%) prevailed. Subtypes VA and VB were distinguished within type V. Altogether 20.3% of strains were classified as belonging to these subtypes. Their lytic reaction was weaker with phages 3, 4, and 9 with the characteristic range of phage type V strains. Among tested strains types I, XIII, and XVI were also represented composing 2, 6, 0, 9, and 0.3% of total number of strains respectively. 1.5% of strains were nontypable and 0.2% showed lytic reactions different from that included in up to now used scheme of typing. It can be concluded that lactose-fermenting S. agona strains show susceptibility to lowered number of phages than typical for Salmonella species strains. It seems that differentiation of this atypical biochemical variant of S. agona with, the use of phage set used up to now may be also usefull in practice as it is the case in respect to strains with typical biochemical properties.

[Correlations between lactose-fermenting capacity, sensitivity to antibiotics and bacteriophage types of Salmonella agona strains]. / Ocena korelacji miedzy zdolnoscia fermentowania laktozy, wrazliwoscia na antybiotyki i typem fagowym paleczek Salmonella agona.

Correlation between the ability to ferment lactose, sensitivity to chemotherapeutic agents and phage type of lactose fermenting and nonfermenting S. agona strains was shown in this study. The difference in sensitivity of two S. agona variants toward gentamicin, tobramycin and chloramphenicol was shown. Lactose fermenting S. agona strains were resistant to the above listed antibiotics. The percentage of the resistant strains was 95.3%, 96.9% and 95.3%, respectively. S. agona strains typable by biochemical tests were more often sensitive to those antibiotics. The percentage of the resistant strains of S. agona with typical biochemical properties was for gentamicin 19.4%, tobramycin 3.7% and chloramphenicol 6.7%. Moreover, the percentage of lactose fermenting S. agona strains resistant to seven other out of seventeen tested antibiotics was 83.8% on average and it was 20% higher than percentage of biochemically typical S. agona strains resistant to the same antibiotics. Lactose fermenting S. agona strains belonged almost four times more frequently to subtype VB and also more often to phage type XI; on the other hand six times rare to phage type I in comparison to biochemically typical S. agona strains.

[Selection of methods of detecting lactose-fermenting Salmonella strains and evaluating their usefulness for diagnostic studies]. / Dobór metod wykrywania fermentujacych laktoze paleczek Salmonella i ocena ich przydatnosci do badan diagnostycznych.

Salmonella rods of subspecies I, lactose-fermenting were first isolated in Poland in 1980. They were isolated from a plus sample taken from a brain abscess of a child. Next strains were isolated from faeces of newborn and hospitalized children. Growth characteristic of colonies of lactose-fermenting Salmonella strains on selective-differentiating media (Mac Conkey's Levine, SS, Soltys) recommended for inoculation of clinical material resembled Escherichia coli. So far these type of colonies were omitted in diagnostic examinations. Lactose-fermenting variants showed on Bismuth sulfate agar "Difco" (WB) typical for Salmonella growth pattern. They grew on this medium after 48 hr of incubation in a form of black, medium sized colonies, with some metallic brilliance and characteristic blackening of the medium undercolonies. Precise knowledge of biochemical properties of lactose-fermenting Salmonella allows to supplement so far used diagnostic scheme with additional tests permitting differentiation of lactose-fermenting variants of Salmonella from the other members of Enterobacteriaceae family. Taking into consideration biochemical variants in diagnostic procedure i.e. lactose-fermenting Salmonella, allowedns to isolate in the years 1983-1985 lactose-positive strains in 1305 out of 2773 (47%) individuals positive for S. agona. In 1987, 246 persons (28.3%) out of 869 with lactose-fermenting Salmonella of various serotypes were simultaneously infected with lactose-negative variant. Lactose-fermenting strains of Salmonella belonged most frequently to the following genera: S. agona, S. enteritidis, S. oranienburg, S. typhimurium, and S. goldcoast. It was found that the modified diagnostic procedure makes possible the isolation and the identification of lactose-positive varians of Salmonella.

Differential typing of Salmonella agona: type divergence in a new serotype.

An international collection of 419 isolates of Salmonella agona was phage typed, biotyped and colicine typed. Of 16 recognized phage types, 15 were represented. Three phage types (I, V and XVI) accounted for 84% of all isolates, were widely distributed and may be interconvertible. Biotyping afforded little type differentiation; thus 92.6% of the isolates belonged to biotype 1 a. A rhamnose non-fermenting variant line (of biotype 5a) became established in Zaire from 1979 to 1980. A maltose late-fermenting line of biotype 1 a, isolated in Scotland in 1974, did not thereafter become established. Two Col+ lines (producing colicine I b) accounted for 45 of 68 colicinogenic isolates. The implication of type diversification and the phylogenetic significance of these findings are discussed.