A total of 103 strains of Aeromonas spp. isolated from clinical and from environmental samples was compared by using SDS-PAGE of periplasms proteins patterns. Strains isolated from Polish children suffering from gastroenteritis did not appear similar to strains isolated from human living in Hong-Kong. Aeromonas sp. strains did not show a tendency to cluster according to their origin. Our results have demonstrated no species-specifs periplasms protein profiles. A significant protein electrophoretic heterogeneity was observed within the species A. hydrophila, A. hestiarum, A. salmonicida, A. caviae, A. media, and A. vermin biotype sobria.
Studies were conducted on the improvement of A. culicicola identification. This species is phenotypically very similar to A. veronii biotype sobria, A. sobria, and A. allosaccharophila. The sequences of 16S rDNA of A. culicicola isolates show the highest similarity with A. jandaei, A. veronii, and A. caviae. Digestion of 16S rDNA PCR product with Alul and Mbol restriction endonucleases allowed discriminating A. culicicola from all other Aeromonas species with the exception of A. jandaei. Additional digestion of 16S rDNA PCR product with BceAI showed a possibility of distinguishing A. jandaei from A. culicicola.
We examined 12 pairs of strains of Escherichia coli and Klebsiella pneumoniae isolated from mixed infections in human for the presence of the Yersinia high-pathogenicity island (HPI). In one case both isolates carried the HPI, whereas in 11 cases one strain of the pair was HPI-positive. Although there were differences in the organization of the Yersinia HPI, all HPI-positive isolates were able to produce yersiniabactin. The presence of the Yersinia HPI may enhance the capability of strains involved in mixed infections to replicate in irondeprived conditions in the host.
The aim of the work was to estimate the insecticidal activity of Bacillus thuringiensis MPU B9 spore-free preparation of crystals against Leucoma salicis caterpillars (willow and poplar pest). The results revealed a high biological activity of B. thuringiensis MPU B9 crystals towards L. salicis larvae. This may be caused by production of numerous, different crystalline proteins by the MPU B9 isolate. The high value of insecticidal activity make this strain a promising candidate for future research on a new efficient preparation against plant pests.
Staphylococcus hominis is a part of normal skin flora, but it is also a cause of nosocomial infections. The aim of this study was to investigate the genetic relatedness of 62 strains of S. hominis obtained from hospitalised patients during an 11-year period. For the discrimination of these clinical strains we used repetitive sequence-based PCR method (BOX-PCR) and multiple-locus variable-number tandem repeat analysis (MLVA). BOX-PCR analysis revealed a large genetic diversity among clinical strains and we did not find a predominant clone with the ability to persist in a hospital environment. MLVA is not as discriminatory as BOX fingerprinting and would not be a useful method for epidemiological studies.
This work aims to provide an insight into staphylococcal cassette chromosome mec elements and antibiotic resistance in clinical isolates of Staphylococcus epidermidis. The dominating type was SCCmec – IV. Fifteen isolates were assigned to SCCmec type III, two isolates to SCCmec type II. Most isolates were resistant to at least three of the non-β-lactam antibiotics tested. None of the strains exhibited resistance to new generation antibiotics, such as daptomycin and linezolid. Also, none of these strains showed resistance to tigecycline and only four strains were resistant to rifampin i.e. antibiotics which are very efficient in treating biofilm-associated infections.
By using PCR reactions we assessed the abundance of vip3A gene in the genomes of 10 Bacillus thuringiensis strains. We estimated Vip toxin activity by adding bacterial culture filtrates into the diet given to Spodoptera exigua caterpillars. Nine of ten filtrates caused death among larvae, and the mortality varied between 12 and 100%. The method used in this study allows fast identification of strains producing Vip-proteins and preliminary evaluation of their insecticidal activity.
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