| Abstract: | The aim of this study was to compare some of the properties of 28 lactose-positive and 28 lactose-negative Salmonella agona strains isolated from faeces of infants hospitalized in the same hospital. Some of biochemical properties, sensitivity to 14 antibiotics and chemotherapeutic agents and sensitivity to bacteriophages used for typing of this Salmonella genus were tested. Results of biochemical examinations revealed that lactose-fermenting strains retain the remaining of Salmonella of subspecies I. Two biochemical features are of particular importance: the ability to ferment lactose on all lactose containing media and a lack of the ability to produce H2S on Kligler medium. These two features differentiate lactose-fermenting strains of Salmonella from non-lactose fermenting ones. Antibiotic sensitivity pattern differed between lactose-positive and lactose-negative strains. Lactose-positive strains showed higher degree of resistance than lactose-negative strains. The differences in resistance were seen in the case of chloramphenicol, doxycycline, gentamicin and tetracycline. Both lactose-positive and lactose-negative strains were sensitive to colistin, neomycin, nitrofurantoin and nalidixic acid. They were resistant to ampicillin, cloxacillin, rifampicin, streptomycin, sulfatiazol and biseptol. Bacteriophage typing revealed that all lactose-negative strains isolated in this study from clinical samples belonged to the same phage pattern V. Lactose-positive strains belonged to two phage types VB and XI. Type VB prevailed. |
